JP2008107465A - Fixing device and image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a fixing device capable of suppressing lubricant from reaching a pressure member, and to provide an image forming apparatus. <P>SOLUTION: A blocking member 32 for blocking the flow of the lubricant from the surface on the endless belt 14 side of the sheet-like member 30 toward the surface on the pressure member 16 side is disposed at least at each axial end of the endless belt 14 on the surface coming in contact with the pressure member 16 of the sheet-like member 30. Consequently, such a failure is suppressed that the lubricant comes in contact with the pressure member 16 after going round from the surface coming in contact with the endless belt 14 of the sheet-like member 30 toward the surface coming in contact with the pressure member 16 during a fixing operation. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a fixing device and an image forming apparatus, and more particularly to a fixing device and an image forming apparatus including the fixing device.

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 the pressurized area between the endless belt and the fixing roll, unfixed toner on the recording medium is fixed on the recording medium.

  In the fixing device having such a configuration, the outer peripheral surface of the endless belt is pressed against the surface of the fixing roll by pressing the endless belt toward the fixing roll by the pressure member. The inner peripheral surface of the endless belt may be worn due to sliding resistance, and if the recording medium is passed between the endless belt and the fixing roll in the worn state, the endless belt is uniform between the fixing roll and the endless belt. There is a concern that pressure is hardly applied, toner is not sufficiently fixed, and image quality is deteriorated.

  In addition, when the inner peripheral surface of the endless belt is worn, the burden on the driving unit such as a motor for transporting the endless belt becomes larger than when no wear has occurred, and there is a concern that the power consumption may increase. There was concern about the damage of the department.

  Therefore, the present applicant has already proposed the techniques described in Patent Document 2, Patent Document 3, and Patent Document 4 in order to solve the above problems.

  According to the techniques of Patent Documents 2 to 4, the surface of the pressure member is covered with a sliding sheet impregnated with polytetrafluoroethylene, and a lubricant such as silicone oil is provided between the pressure member and the endless belt. Is applied and supplied.

  The sliding sheet for protecting the surface of the pressure member used in these technologies is a glass fiber sheet impregnated with polytetrafluoroethylene (PTFE), and a glass fiber cloth composed of glass fibers is made of polytetrafluoroethylene. It was obtained by impregnating and firing ethylene. In addition, there is also a case where the PTFE-impregnated glass fiber sheet is coated with a modified PTFE film or the like, and is thickened by thermocompression bonding.

The sliding sheet has a fluororesin surface excellent in slidability. In addition, since the glass cloth as a base material has glass fiber stitches, the surface of the sheet has a certain degree of surface irregularities. When the sliding part is used in combination with a lubricant such as silicone oil, the oil in this concave part Can enter and maintain good lubrication with the sliding surface. For this reason, abrasion between the endless belt and the pressure member can be suppressed by holding the lubricant on the surface of the sliding sheet.
JP-A-8-262903 JP-A-10-213984 Japanese Patent Laid-Open No. 10-228196 Japanese Patent Laid-Open No. 11-45018 etc.

However, according to the above prior art, although the wear of the endless belt by the pressure member can be suppressed by holding the lubricant on the surface of the sliding sheet, the lubricant held on the surface of the sliding sheet is gradually increased. When the lubricant spreads and reaches the end of the sliding sheet, and the lubricant gradually wraps around the back surface of the sliding sheet and reaches the pressure member, the material constituting the pressure member changes due to the influence of the lubricant. There was a concern that the applied pressure would fluctuate.
For example, when silicone rubber is used as the material constituting the pressure member, the size and hardness of the pressure member change due to the influence of the lubricant, making it difficult to apply uniform pressure to the recording medium in the fixing device. There was concern to become.

  An object of the present invention is to provide a fixing device and an image forming apparatus capable of suppressing the lubricant from reaching the pressure member.

  In order to solve the above problems, a fixing device of the present invention includes a fixing member that is rotatably arranged, an endless belt that sandwiches and conveys a recording medium between the fixing member, and an inner periphery of the endless belt. A pressurizing unit disposed on the side and forming a pressurizing region where pressure is applied to the fixing member by applying pressure to the fixing member via the endless belt or the endless belt and the recording medium And a lubricant supplying means for supplying a lubricant to the inner peripheral surface of the endless belt, and at least a part of the region is interposed between the pressurizing means and the endless belt, and at least the lubricant is supplied to the endless belt. A sheet-like member held on the surface of the sheet-like member, and a surface of the sheet-like member on the side of the pressing means, provided at least at both axial ends of the endless belt, from the surface of the sheet-like member on the endless belt side The above Towards the surface of the unit side and a, a shielding member for shielding said lubricant flows.

  The shielding member is provided in a region continuous with the pressure region in at least both axial ends of the endless belt on the surface of the sheet-like member on the pressure means side.

  Moreover, it is preferable that the said shielding member is further provided in the conveyance direction upstream side edge part of the said endless belt of the surface at the said pressurization means side of the said sheet-like member.

  The shielding member may be provided integrally with the sheet-like member, and may be configured to include a region where an end portion of the sheet-like member is bent toward the pressurizing unit side. It may be configured to be laminated on an end portion of the surface of the shaped member on the pressing means side via an adhesive.

  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. The recording medium is sandwiched and conveyed between the developing means for forming the toner image, the transfer means for transferring the toner image on the image carrier to the recording medium, the fixing member rotatably disposed, and the fixing member. Pressure is applied between the endless belt and the fixing member by applying pressure to the fixing member via the endless belt or the endless belt and the recording medium. Pressurizing means for forming a pressurized area, lubricant supply means for supplying a lubricant to the inner peripheral surface of the endless belt, and at least a partial area interposed between the pressurizing means and the endless belt The lubricant is at least the endless base. A sheet-like member held on the surface of the sheet-like member, and a surface of the sheet-like member on the side of the pressing means, provided at least at both axial ends of the endless belt, and the surface of the sheet-like member on the endless belt side A shielding member for shielding the flow of the lubricant from the pressure means toward the surface on the pressure means side, and recording the toner image on the recording medium onto which the toner image has been transferred by the transfer means And a fixing device for fixing on the medium.

  According to the fixing device and the image forming apparatus of the present invention, it is possible to provide a fixing device and an image forming apparatus that can suppress the lubricant from reaching the pressure member.

  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. The pressed region N is formed.

  A recording medium K carrying unfixed toner T is transported to a pressure region N between the endless belt 14 and the fixing roll 12 by a transport mechanism (not shown). The toner T is fixed on the recording medium K by being nipped and conveyed.

  As shown in FIG. 2, the fixing roll 12 includes 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 the core 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 T 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 endless belt 14 that is in contact with the fixing roll 12 and sandwiches and conveys the recording medium K to and from the fixing roll 12 may be endless and in the form of a sheet, and the shape, size, and the like are not particularly limited. However, it can be used by appropriately selecting from known ones according to the purpose.

  The structure of the endless belt 14 may be a single-layer structure, but in the present embodiment, as shown in FIG. 4, a structure in which a release layer 14B is formed on the surface of a base material 14A is used.

  Examples of the material of the base material 14A include heat-resistant polymers such as thermosetting polyimide, thermoplastic polyimide, polyamide, and polyamideimide, and metals such as stainless steel, nickel, and copper. In this embodiment, the thickness is 80 μm. The case where a polyimide base material is used is demonstrated.

  The release layer 14B is preferably excellent in releasability with respect to the toner, and examples of the material include PTFE (polytetrafluoroethylene), PFA (tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer), and FEP. Examples include fluororesins such as (tetrafluoroethylene-hexafluoropropylene copolymer). In this example, a case where PFA having a thickness of 25 μm is used will be described.

  As shown in FIG. 3, the pressurizing 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 a biasing member 20 such as a coil spring is connected to the support member 16B. The other end of the urging member 20 is supported by a metal support 22. The support 22 is provided with a guide member 24 for supporting traveling of the endless belt 14 in the outer peripheral direction via a support member (not shown).

The pad 16A is urged by the urging member 20 through the support member 16B in a direction approaching the outer peripheral surface of the fixing roll 12 with a predetermined pressure (for example, 1 to ² kg / cm ² ).

  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.

  A lubricant supply member 26 for supplying a lubricant to the inner peripheral surface of the endless belt 14 is provided on the inner peripheral surface side of the endless belt 14.

  The lubricant supply member 26 includes an application member 28 disposed in contact with the inner peripheral surface of the endless belt 14 and a support member (not shown) that supports the application member 28. The application member 28 is impregnated with a lubricant in advance.

  As the application member 28, a material having a heat resistance of 130 ° C. or higher, preferably 200 ° C. or higher is used. As the application member 28, a nonwoven fabric made of polyamide, polyimide, polyamideimide or the like is suitably used. be able to. The supporting member that supports the coating member 28 is a member that does not permeate and impregnate a release agent and has a heat resistance of 130 ° C. or higher. Specifically, a metal such as aluminum, iron, stainless steel, copper, or the like Further, heat resistant resins such as polycarbonate and melamine resin can be used.

  As the lubricant, a silicone oil having a viscosity of 50 to 3000 cs at room temperature (25 ° C.) and a humidity of 50% RH can be suitably used. As such silicone oil, amino-modified silicone oil, dimethyl silicone oil, mercapto-modified silicone oil, dimethyl silicone oil, mercapto-modified silicone oil and the like can be used.

  When the viscosity of the lubricant is less than 50 cs, the function of lubricating the inner peripheral surface of the endless belt 14 is not satisfied by evaporation. When the viscosity is higher than 3000 cs, the endless belt 14 is endless by the lubricant supplied to the inner peripheral surface. There may be a problem that the frictional resistance between the belt 14 and the member provided in contact with the inner peripheral surface of the belt 14 increases.

  Here, in the amino-modified silicone oil, as shown in the following general formula (1), since the amino group shows basicity, in the presence of an acidic substance, the reaction is accelerated by the heat of the fixing roll 12, and neutralization is performed. Viscosity may increase or insoluble matter may be generated.

Therefore, by using a hindered amine oil in which about 500 ppm of an antioxidant having a structural formula as shown in the following general formula (2) is added to the amino-modified silicone oil, as shown in the following general formula (3), the amino-modified silicone is used. By trapping (resonating) H, which is an active radical when the amino group in the oil is oxidized, with the benzene ring of the amine of the antioxidant, the chain reaction due to neutralization of the amino-modified silicone oil can be suppressed, It can suppress that an amino modified silicone oil increases a viscosity by neutralization or generates insoluble matter.
For this reason, it is particularly preferable to use hindered amine oil as the lubricant.

  The application member 28 impregnated with the lubricant is provided in contact with substantially the entire area of the endless belt 14 in the axial direction. For this reason, the lubricant can be supplied to the entire inner peripheral surface of the endless belt 14 as the endless belt 14 rotates.

  Between the endless belt 14 and the pressure member 16, a sheet-like member 30 for suppressing friction between the endless belt 14 and the pressure member 16 is provided. For this reason, the pressure member 16 forms the pressure region N by pressing the endless belt 14 to the fixing roll 12 via the sheet-like member 30.

  The sheet-like member 30 only needs to be provided so as to cover at least the region including the pressure region N between the endless belt 14 and the pressure member 16, and as shown in FIG. It may be a member that is long in the axial direction, or may be a member that is long in the circumferential direction of the endless belt 14 as shown in FIG.

  For example, as shown in FIG. 6 (A), the sheet-like member 30 has an upstream end 30A in the conveying direction of the endless belt 14 (see the direction of arrow A in FIGS. 1, 5, and 6). It is fixed by being sandwiched by members constituting the support 22 and is disposed so as to cover the endless belt 14 along the downstream side in the conveying direction via the pressure region N. In addition, the conveyance direction downstream end part 30B of the endless belt 14 of the sheet-like member 30 may be left in a free state without being fixed, or may be fixed.

  As shown in FIG. 7, the sheet-like member 30 is configured by sequentially laminating a porous resin layer 34 and a film layer 36 on a lubricant permeation prevention layer 31.

  The porous resin layer 34 is formed by subjecting a fluorine-based resin to stretch molding, sintering molding, or the like, and has a large number of fine holes for holding a lubricant. The lubricant permeation preventive layer 31 is laminated on the pressure member 16 side, and is thin such as FEP (tetrafluoroethylene-hexafluoropropylene copolymer), polyimide, polyamide, polyamideimide, stainless steel, nickel, copper, aluminum, PET, or the like. Made of film. The film layer 36 is laminated on the side of the porous resin layer 34 that contacts the endless belt 14, and the lubricant permeation preventive layer 31 is laminated on the side that contacts the pressure member 16.

  The thickness of the sheet-like member 30 is 50 μm to 4 mm, preferably 80 μm to 500 μm. If the thickness of the sheet-like member 30 is less than 50 μm, sufficient strength that can withstand sliding stress such as friction in the pressurizing region N cannot be obtained, lubricant retention cannot be obtained, and the thickness is 4 mm. If the pressure exceeds N, a sufficient pressure cannot be uniformly applied to the fixing roll 12, and the contact width (so-called nip width) with the fixing roll 12 in the conveying direction of the endless belt 14 in the pressure region N is uniform. It becomes difficult to obtain.

  As the porous resin layer 34, for example, a porous resin layer made of a porous resin obtained by stretching and sintering PTFE (polytetrafluoroethylene) resin may be used. Used. The shape of the porous resin layer 34 may be selected as appropriate, such as a film shape, a woven fabric shape, and a film / woven fabric bonded shape. However, in this embodiment, fibers formed of a porous resin are used. What consists of woven fiber (porous resin fiber woven fabric) is used.

  The thickness of the porous resin layer 34 is preferably 50 μm to 1 mm, and more preferably 80 μm to 200 μm. If the thickness is less than 50 μm, sufficient strength to withstand sliding stress such as friction in the pressurizing region N cannot be obtained. If the thickness exceeds 1 mm, sufficient pressure is uniformly applied to the fixing roll 12. Further, it is difficult to obtain a uniform width in the outer circumferential direction in the pressure region N.

  The film layer 36 is not necessarily provided, but by providing the film layer 36 on the surface, the smoothness of the surface of the sheet-like member 30 can be improved, and durability and sliding resistance are further reduced. It becomes possible. However, when the film layer 36 is provided, the film layer 36 itself has a lubricant permeability, and the film layer 36 may be any film as long as it can penetrate the lubricant as a result.

  The film layer 36 is made of a fluororesin layer such as PTFE, and the thickness is preferably 10 μm to 80 μm, and more preferably 20 μm to 40 μm. When the thickness of the film layer 36 is less than 10 μm, wear of the film layer 36 occurs due to sliding stress in the pressure region N, and sufficient strength and lubricant retention cannot be obtained. On the other hand, when the thickness exceeds 80 μm, the heat conductivity of the fluororesin is low and the heat transfer in the pressure region N is hindered, and the fixability of the toner T to the recording medium K may be deteriorated.

  As shown in FIG. 8, the lubricant held on the surface of the sheet-like member 30 on the side in contact with the endless belt 14 is applied to the sheet-like member 30 through the end face of the sheet-like member 30. A shielding member 32 is provided for suppressing the flow to the side in contact with.

  The shielding member 32 is provided on at least both axial ends of the endless belt 14 on the surface of the sheet-like member 30 on the side in contact with the pressure member 16.

  As shown in FIG. 6 (A), the shielding member 32 is provided at both end portions of the surface of the sheet-like member 30 on the side in contact with the pressing member 16 in the axial direction of the endless belt 14 (in the direction of arrow C in FIG. 6). It is provided at least in a region continuous with the pressurizing region N.

  Although it is essential that the shielding member 32 is provided in such a region, as shown in FIG. 6B, the surface of the endless belt 14 on the side in contact with the pressure member of the endless belt 14 is provided. It may be provided over the entire region of both axial end portions. Further, as shown in FIG. 6 (C), a region of the surface of the sheet-like member 30 on the side in contact with the pressure member that is sandwiched by the members constituting the support 22 (the upstream end of the endless belt 14 in the conveyance direction) It may be provided at all ends other than 30A).

  When the shielding member 32 is fixed to the inner peripheral side of the endless belt 14 without the shielding member 32 being sandwiched between the members constituting the support 22 as described above, the shielding member 32 is attached to the sheet-like member 30. You may make it provide in the whole edge part except this fixed part in the surface on the side which touches the pressurization member 16.

As shown in FIG. 9A, the shielding member 32 has adhesive layers (not shown) made of an adhesive on both ends of the endless belt 14 of the sheet-like member 30 in the axial direction (the direction of arrow C in FIG. 9). It is provided so that it may adhere via.
The shielding member 32 has the lubricant held on the surface of the sheet-like member 30 on the side in contact with the endless belt 14 wraps around the end surface of the sheet-like member 30 and wraps around the surface on the side in contact with the pressure member 16. 9 (B), a region in which both end portions in the axial direction of the endless belt 14 of the sheet-like member 30 are folded back toward the side in contact with the pressing member 16 as shown in FIG. The shielding member 32 may be used. Further, in order to further improve the shielding effect, as shown in FIG. 9C, both end portions in the axial direction of the endless belt 14 of the sheet-like member 30 are mountain-folded and valley-shaped toward the side in contact with the pressing member 16. It is good also as an area | region folded so that folding might be continued.

  As shown in FIG. 9A, when the shielding member 32 is provided so as to adhere to both end portions in the axial direction of the endless belt 14 of the sheet-like member 30 via an adhesive layer made of an adhesive, the shielding member 32 is provided. Is preferably made of a material that can be impregnated with a release agent. Specific examples of such materials include, for example, sponge-like absorbents made of polypropylene, polystyrene, polyurethane, polyvinyl alcohol, polyethylene, and the like, and thin fibers such as acrylic fibers, nylon fibers, urethane fibers, and polyethylene fibers. Felt-like absorbers formed in this manner, and those having an appropriate pore structure.

  As a method for adhering the shielding member 32 to the sheet-like member 30, a known surface treatment method such as alkali etching treatment, sputter etching treatment, dry etching treatment or the like is used for both axial ends of the endless belt 14 of the sheet-like member 30. After the surface treatment, an adhesive may be applied, and the shielding member 32 may be placed on and adhered to the adhesive layer formed by the adhesive application.

  As the adhesive, an acrylic adhesive or a silicone adhesive having excellent heat resistance can be used. Moreover, you may use the double-sided tape using an acrylic adhesive, a silicone adhesive, etc. as an adhesive layer.

  In the above configuration, in the fixing device 10 according to the present embodiment, the side of the sheet-like member 30 interposed between the endless belt 14 and the pressure member 16 that contacts the endless belt 14 is as follows. It is possible to prevent the pressure member 16 from flowing to the surface on the side in contact with the pressure member 16 and reaching the pressure member 16, and the deterioration of the pressure member 16 due to the lubricant 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 the recording medium K holding the unfixed toner image T exists 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 image T is fixed on the recording medium K by heating and pressing.

  When rotation of the endless belt 14 is started, the lubricant is supplied to the inner peripheral surface of the endless belt 14 by the lubricant supply member 26. The lubricant supplied to, or applied to, the inner peripheral surface of the endless belt 14 reaches the pressure region N as the endless belt 14 rotates, and contacts the surface of the sheet-like member 30 (the endless belt 14 of the sheet-like member 30). And is gradually supplied to the inner surface of the endless belt 14.

  Since the sheet-like member 30 includes the porous resin layer 34, the lubricant held on the sheet-like member 30 is held in a state where the porous resin layer 34 is impregnated. The lubricant impregnated in the porous resin layer 34 gradually oozes out from the porous resin layer 34 onto the surface of the sheet-like member 30, and a certain amount of lubricant is always on the surface of the sheet-like member 30. Is uniformly applied.

  For this reason, since the lubricant is interposed between the endless belt 14 and the sheet-like member 30, the endless belt 14 is rotated by the endless belt 14 rotating while being pressurized by the pressure member 16. It is possible to suppress wear on the inner peripheral surface.

  Here, the lubricant that has oozed out on the surface of the sheet-like member 30 on the side of the endless belt 14 wraps around the surface of the sheet-like member 30 on the side in contact with the pressure member 16 through the end surface of the endless belt 14, When the pressure reaches 16, the pressure member 16 is deteriorated, and it may be difficult to apply a target pressure between the endless belt 14 and the fixing roll 12.

However, in the sheet-like member 30 provided in the fixing device 10 of the present embodiment, the position described with reference to FIGS. 6A to 6C at the end of the surface on the side in contact with the pressure member 16. A shielding member 32 is provided.
The surface of the sheet-like member 30 on the side in contact with the pressing member 16 through the end face of the endless belt 14 is held by the shielding member 32 on the surface of the sheet-like member 30 on the side in contact with the endless belt 14. It is possible to suppress the flow to the contact position with the pressure member 16.

  Therefore, deterioration of the pressure member 16 can be suppressed.

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

As shown in FIG. 10, 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. 10).
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. 10) 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.

As described above, according to the image forming apparatus 50 of the present embodiment, the fixing device 10 is provided, and the fixing device 10 is provided on the pressure member 16 from the surface of the sheet-like member 30 on the endless belt 14 side. A shielding member 32 is provided to shield the lubricant from flowing toward the side surface. The shielding member 32 is provided on at least both axial ends of the endless belt 14 on the surface of the sheet-like member 30 on the side in contact with the pressure member 16. For this reason, at the time of fixing, the lubricant wraps around from the surface on the side in contact with the endless belt 14 of the sheet-like member 30 to the surface on the side in contact with the pressure member 16, so that the lubricant contacts the pressure member 16. Can be suppressed.
As described above, the shielding member 32 prevents the lubricant from coming into contact with the pressure member 16 from the surface of the sheet-like member 30 on the side in contact with the endless belt 14 to the surface on the side in contact with the pressure member 16. Therefore, the pressure fluctuation applied to the recording medium K at the time of fixing can be suppressed, and the image quality deterioration due to the pressure fluctuation at the time of fixing the toner image onto the recording medium K can be suppressed.

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

(Example 1)
FIG. 6A shows a cloth made of a fluororesin-coated glass woven fabric in which a modified PTEFE film having a thickness of 25 μm is fused on both sides of a plain weave glass cloth fabric (manufactured by Chuko Kasei Kogyo Co., Ltd., trade name: FGF200-4). A sheet having a long side of 33.0 cm (maximum length in the direction of arrow C in FIG. 6) and a short side of 5.5 cm (maximum length in the direction of arrow A in FIG. 6) are punched using a sheet punching die. A shaped member was created.

  Next, the surface treatment layer is formed by etching both ends of the sheet-like member in the C direction in FIG. 6 (in a range of 5 mm from the side edge in the C direction in FIG. 6) using a dry etching apparatus. Formed.

Next, after applying one side of the double-sided pressure-sensitive adhesive tape (Dainippon Ink Chemical Co., Ltd., trade name: DAITAC # 810HD) using acrylic adhesive to each etched area, the other side is shielded. As members, heat-resistant felt sheets (trade name NOMEX FELT, thickness 3 mm, width 4 mm, length 40 mm and 330 mm, manufactured by Deyupon Co., Ltd.) were bonded to each other.
Thereby, as shown in FIG.6 (C), the heat resistant felt sheet | seat as a shielding member was provided in the edge part whole region except the conveyance direction upstream edge part.

Next, a product name: ApeosPort C4535 I manufactured by Fuji Xerox Co., Ltd. was prepared as an image forming apparatus, and the fixing device of this image forming apparatus was modified to the structure shown in FIG.
The setting of the fixing device was as follows.

-Configuration of the pad 16A of the pressure member 16: length 320 mm x width 8 mm x thickness 4.7 mm
Material: Heat-resistant silicone rubber / Pressurizing force with pressure member (pressure against endless belt fixing roll) 1.2 kg / cm ²
The width in the conveying direction of the endless belt in the contact area between the fixing roll and the endless belt (so-called nip width) 10 mm
・ Fixing roll surface temperature 185 ℃
Mold release agent: hindered amine oil (manufactured by Shin-Etsu Chemical Co., Ltd., trade name: X22-9446, viscosity at 30 ° C., humidity of 30 ° C. and humidity of 30 cs)
Application member 28 (material: heat-resistant polyamide fiber NOMWX FELT, length 312 mm × width 7 mm × thickness 5 mm) was impregnated with 4 cc of the release agent. (The 312 mm × 7 mm surface of the application member 28 was placed in contact with the inner periphery of the endless belt.)
Installation position of the sheet-like member: The sheet-like member 30 created as described above is interposed between the pressure member 16 and the endless belt 14 of the fixing device 10, and a shielding member 32 is provided on the pressure member 16 side. The sheet-like member 30 was arrange | positioned so that a surface might be located. Then, the upstream end portion 30A of the sheet-like member 30 in the conveying direction of the endless belt 14 (see the direction of arrow A in FIG. 1) is fixed by being sandwiched by the members constituting the support 22, and the pressure region The endless belt 14 is disposed so as to cover the downstream side in the transport direction via N. Further, the end portion 30B of the endless belt 14 in the conveyance direction of the endless belt 14 is not fixed and is left in a free state.

  By disposing the sheet-like member 30 in this way, the shielding member 32 provided on the sheet-like member 30 is disposed so as to be located at a position continuous to the pressurizing region N, and the sheet-like member 30 is provided. The endless belt 14 is disposed at both ends in the axial direction and at the downstream end in the conveying direction.

  For the image forming apparatus configured as described above, an image is formed by printing 100 sheets of a black image with a density of 100% on an A4 size P paper (manufactured by Fuji Xerox Co., Ltd.) at an output speed of 45 sheets / min. After the processing, a series of steps of resting for 1 hour was repeated, and 3000 image formation tests were performed.

After the image formation test, the fixing device 10 is disassembled, the sheet-like member 30 is taken out, and the surface of the sheet-like member 30 provided with the shielding member 32 is visually inspected for the presence of lubricant. No evidence of lubricant was found in the entire region other than the region where the shielding member 32 was placed on the surface on the side in contact with the pressure member 16.
For this reason, in Example 1, it can be said that the wraparound of the release agent from the surface of the endless belt 14 side of the sheet-like member 30 to the surface of the pressure member 16 side is suppressed.

(Example 2)
In the same manner as in Example 1, sputtering treatment and etching treatment were performed on the entire end portion of the sheet-like member 30 prepared in Example 1 except for the upstream end and the downstream end in the conveyance direction of the sheet-like member 30. Later, after applying one side of the double-sided adhesive tape (made by Dainippon Ink & Chemicals, Inc., trade name: DAITAC # 810HD), which uses an acrylic adhesive, to the etched area, As a shielding member, heat-resistant felt sheets (manufactured by Deyupon, trade name: NOMEX FELT, thickness: 3 mm, width: 4 mm, length: 50 mm) were bonded to each other.
Thereby, as shown in FIG. 6 (B), the heat-resistant felt sheet as the shielding member was provided in the entire end portion excluding the downstream end portion and the upstream end portion in the conveying direction of the sheet-like member 30.

The sheet-like member 30 created as described above is interposed between the pressure member 16 and the endless belt 14 of the fixing device 10, and the sheet-like member 30 is positioned so that the surface provided with the shielding member 32 on the pressure member 16 side is located. The member 30 was arranged. Then, the upstream end portion 30A of the sheet-like member 30 in the conveying direction of the endless belt 14 (see the direction of arrow A in FIG. 1) is fixed by being sandwiched by the members constituting the support 22, and the pressure region The endless belt 14 is disposed so as to cover the downstream side in the transport direction via N. Furthermore, the end 30B of the endless belt 14 in the conveyance direction of the endless belt 14 is not fixed and is left in a free state.
By arranging the sheet-like member 30 in this way, the shielding member 32 provided on the sheet-like member 30 has a part of the region located at both ends in the axial direction of the endless belt 14 of the sheet-like member 30. It was located at a position continuous to the pressurizing region N and was disposed at both axial ends of the endless belt 14.

An image forming test is performed in the same manner as in Example 1 except that the sheet-like member 30 is configured as described above. After the image-forming test, the fixing device 10 is disassembled and the sheet-like member 30 is taken out. When the presence or absence of lubricant on the surface on which 30 shielding members 32 are provided is visually inspected, all regions other than the installation region of the shielding member 32 on the surface of the sheet-like member 30 on the side in contact with the pressure member 16, There was no evidence of lubricant.
For this reason, in Example 1, it can be said that the wraparound of the release agent from the surface of the endless belt 14 side of the sheet-like member 30 to the surface of the pressure member 16 side is suppressed.

(Example 3)
When the sheet-like member 30 prepared in the first embodiment is installed in the fixing device 10 among the end portions excluding the upstream end and the downstream end in the conveying direction of the sheet-like member 30, the sheet-like member 30 continues to the pressure region N. A double-sided pressure-sensitive adhesive tape (Dainippon Ink & Chemicals, Inc.) in which an acrylic pressure-sensitive adhesive is used in the region where the etching process was performed after the sputtering process and the etching process were performed in the same manner as in Example 1 Product, product name: DAITAC # 810HD), after attaching one side, as the shielding member on the other side, heat-resistant felt sheet (product name NOMEX FELT, thickness 3mm, width 4mm, length 35mm) Were bonded to each other.
As a result, as shown in FIG. 6 (A), the heat-resistant felt sheet as the shielding member is partially in the end portion excluding the downstream end and the upstream end of the sheet-like member 30 in the conveying direction. Provided.

The sheet-like member 30 created as described above is interposed between the pressure member 16 and the endless belt 14 of the fixing device 10, and the sheet-like member 30 is positioned so that the surface provided with the shielding member 32 on the pressure member 16 side is located. The member 30 was arranged. Then, the upstream end portion 30A of the sheet-like member 30 in the conveying direction of the endless belt 14 (see the direction of arrow A in FIG. 1) is fixed by being sandwiched by the members constituting the support 22, and the pressure region The endless belt 14 is disposed so as to cover the downstream side in the transport direction via N. Furthermore, the end 30B of the endless belt 14 in the conveyance direction of the endless belt 14 is not fixed and is left in a free state.
By disposing the sheet-like member 30 in this way, the shielding member 32 provided on the sheet-like member 30 is a position that continues to the pressurizing regions N at both ends in the axial direction of the endless belt 14 of the sheet-like member 30. Arranged.

An image forming test is performed in the same manner as in Example 1 except that the sheet-like member 30 is configured as described above. After the image-forming test, the fixing device 10 is disassembled and the sheet-like member 30 is taken out. When the presence or absence of lubricant on the surface on which 30 shielding members 32 are provided is visually inspected, all regions other than the installation region of the shielding member 32 on the surface of the sheet-like member 30 on the side in contact with the pressure member 16, There was no evidence of lubricant.
For this reason, in Example 1, it can be said that the wraparound of the release agent from the surface of the endless belt 14 side of the sheet-like member 30 to the surface of the pressure member 16 side is suppressed.

(Comparative Example 1)
The sheet-like member 30 created in the first embodiment is configured not to include the shielding member 32, and the sheet-like member 30 not provided with the shielding member 32 is connected to the pressure member 16 and the endless belt 14 of the fixing device 10. The sheet-like member 30 was arranged so that the surface provided with the shielding member 32 on the pressure member 16 side was located therebetween. Then, the upstream end portion 30A of the sheet-like member 30 in the conveying direction of the endless belt 14 (see the direction of arrow A in FIG. 1) is fixed by being sandwiched by the members constituting the support 22, and the pressure region The endless belt 14 is disposed so as to cover the downstream side in the transport direction via N. Furthermore, the end 30B of the endless belt 14 in the conveyance direction of the endless belt 14 is not fixed and is left in a free state.

  An image forming test is performed in the same manner as in Example 1 except that the sheet-like member 30 is configured as described above. After the image-forming test, the fixing device 10 is disassembled and the sheet-like member 30 is taken out. When the presence or absence of the lubricant on the surface on the side in contact with the pressure member 16 was inspected, the lubricant was present up to the vicinity of the center of the sheet-like member 30 in the axial direction of the endless belt 14.

  As described above, according to the image forming apparatus including the fixing device 10 of the first to third embodiments, the shielding member 32 is provided at least at both axial ends of the endless belt 14 on the surface of the sheet-like member 30 on the pressing member 16 side. Therefore, it can be said that the lubricant can be prevented from wrapping around from the surface on the endless belt 14 side of the sheet-like member 30 to the surface on the pressing member 16 side, as compared with Comparative Example 1.

1 is a schematic configuration diagram illustrating a fixing device according to an exemplary embodiment. FIG. 3 is a schematic diagram illustrating a cross section of a fixing roll. FIG. 2 is a schematic configuration diagram illustrating a main part of a fixing device according to an exemplary embodiment. It is a schematic diagram which shows the cross section of an endless belt. FIG. 2 is a schematic configuration diagram illustrating a main part of a fixing device according to an exemplary embodiment. It is a schematic diagram which shows the shielding member provided on the sheet-like member, (A) (B) (C) shows a mutually different aspect of the area | region in which the shielding member was provided in the edge part of a sheet-like member. It is a schematic diagram. It is a schematic diagram which shows the cross section of a sheet-like member. FIG. 2 is a schematic cross-sectional view of a fixing device. It is a schematic diagram which shows the shape of the shielding member provided in the sheet-like member and the sheet-like member, (A), (B), and (C) are schematic diagrams which each show a different form. 1 is a schematic diagram illustrating an image forming apparatus according to an exemplary embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Fixing device 12 Fixing roll 14 Endless belt 16 Pressure member 28 Application member 30 Sheet-like member 32 Shielding member 50 Image forming device 52 Photoconductor 56 Exposure device 58 Developing device 60 Transfer device

Claims (2)

A fixing member disposed rotatably;
An endless belt for nipping and conveying a recording medium with the fixing member;
A pressurizing region that is disposed on the inner peripheral side of the endless belt, and pressure is applied to the fixing member by applying pressure to the fixing member via the endless belt or the endless belt and the recording medium. Pressurizing means to form,
Lubricant supply means for supplying a lubricant to the inner peripheral surface of the endless belt;
A sheet-like member that is interposed between the pressurizing means and the endless belt, and holds the lubricant on at least the surface of the endless belt;
The sheet-like member is provided on at least both end portions of the endless belt in the axial direction of the surface on the pressing means side, and from the surface on the endless belt side of the sheet-like member toward the surface on the pressing means side. A shielding member for shielding the flow of the lubricant;
A fixing device provided with 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 that is rotatably arranged, an endless belt that sandwiches and conveys the recording medium between the fixing member, and an endless belt or the endless belt that is disposed on an inner peripheral side of the endless belt, and the recording A pressure is applied to the fixing member via a medium to thereby form a pressure region where pressure is applied between the fixing member and a lubricant to the inner peripheral surface of the endless belt. Lubricant supply means, a sheet-like member having at least a partial region interposed between the pressurizing means and the endless belt, and holding the lubricant on at least the surface of the endless belt, and the sheet-like member Of the end surface of the endless belt, and the lubricant flows from the endless belt side surface of the sheet-like member toward the end surface of the endless belt. thing Anda shielding member for shielding a fixing device for fixing on the recording medium the toner image on the recording medium having the toner image transferred by said transfer means,
An image forming apparatus.

Images