JP2012068517A - Mold release member, fixing device, and image forming apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a mold release member having high durability in a heating condition, a fixing device, and an image forming apparatus.SOLUTION: A mold release member includes: a base layer; a mold release layer having a surface that exhibits higher mold releasability than that of the base layer does; and an adhesion layer that is interposed between the base layer and the mold release layer to adhere the base layer and the mold release layer, and contains heat resistance improving particles having average particle diameter of 10 μm or less that improves heat resistance of the adhesion layer.

Description

  The present invention relates to a release member, a fixing device, and an image forming apparatus.

  Conventionally, as an image fixing to a recording medium in an image forming apparatus, a fixing roll whose surface is elastically deformed, a pressure belt capable of running while being in contact with the fixing roll, and a pressure disposed inside the pressure belt Comprising a pad, and a pressure belt is press-contacted with the fixing roll by the pressure pad, and a belt nip is provided between the pressure belt and the fixing roll so that the recording paper can pass through, A fixing device called a belt nip system is known in which the exit side of the recording paper is locally elastically deformed on the surface of the fixing roll (see, for example, Patent Document 1).

  Further, as a fixing roll used in such a fixing device, it has an adhesive layer formed by curing the adhesive composition on the outer periphery of the roll shaft, and has a silicone rubber layer on the outer periphery of the adhesive layer. It is a fixing roll having a surface layer made of a fluororesin on the outside, and selected from fumed silica, precipitated silica, crystalline silica, diatomaceous earth, iron oxide, titanium oxide, cerium oxide, and carbon as a heat improver for the adhesive layer The thing containing 1 type, or 2 or more types is known (for example, refer patent document 2).

Japanese Patent No. 3298354 JP 2007-310212 A

  An object of the present invention is to provide a release member, a fixing device, and an image forming apparatus having high adhesion durability under heating.

The release member according to claim 1 is:
The base layer,
A release layer having a surface exhibiting higher releasability than the releasability exhibited by the surface of the base layer;
An adhesive layer that is sandwiched between the base layer and the release layer to bond the base layer and the release layer, and has an average particle diameter of 10 μm or less and improves the heat resistance of the adhesive layer. An adhesive layer formulated with
It is provided with.

The release member according to claim 2 is:
The adhesive layer is characterized in that triiron tetroxide particles are blended as the heat resistance improving particles.

The release member according to claim 3 is:
The adhesive layer is characterized in that the heat resistance-improving particles are blended and a crosslinking agent that causes three-dimensional crosslinking is blended.

The fixing device according to claim 4 is:
The base layer,
A release layer having a surface exhibiting higher releasability than the releasability exhibited by the surface of the base layer;
An adhesive layer that is sandwiched between the base layer and the release layer to bond the base layer and the release layer, and has a heat resistance improving particle that has an average particle diameter of 10 μm and improves the heat resistance of the adhesive layer. A formulated adhesive layer;
A release member comprising:
A recording medium on which an unfixed image is formed is sandwiched between the release member and the recording medium passes between the release member; and the release member and the above A heater for heating the recording medium passing between the sandwiching members;
It is provided with.

An image forming apparatus according to claim 5
An image forming device for forming an unfixed image on the surface of the recording medium;
A fixing device for fixing the unfixed image on the recording medium onto the recording medium,
The fixing device is
The base layer,
A release layer having a surface exhibiting higher releasability than the releasability exhibited by the surface of the base layer;
An adhesive layer that is sandwiched between the base layer and the release layer to bond the base layer and the release layer, and has an average particle diameter of 10 μm or less and improves the heat resistance of the adhesive layer. An adhesive layer formulated with
A release member comprising:
A recording medium on which an unfixed image is formed is sandwiched between the release member and the recording medium passes between the release member; and the release member and the above A heater for heating the recording medium passing between the sandwiching members;
It is characterized by having.

  According to the release member according to the first aspect, the adhesion durability under heating is high as compared with the case where the present configuration is not provided.

  The release member according to claim 2 has higher adhesion durability under heating than the release member according to claim 1.

  The release member according to claim 3 also has higher adhesion durability under heating than the release member according to claim 1.

  According to the fixing device of the fourth aspect, compared to the case where this configuration is not provided, the adhesion durability under heating is high.

  According to the image forming apparatus of the fifth aspect, the adhesion durability under heating is high as compared with the case where this configuration is not provided.

1 is a schematic configuration diagram illustrating an image forming apparatus according to an embodiment of the present invention. FIG. 2 is a cross-sectional view illustrating a configuration of a fixing device. FIG. 3 is a configuration diagram of a fixing roll. It is a block diagram of an endless belt.

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

[Image forming apparatus]
FIG. 1 is a schematic configuration diagram illustrating an image forming apparatus according to an embodiment of the present invention.

  An image forming apparatus 1 shown in FIG. 1 is an intermediate transfer type printer. The image forming apparatus 1 includes a plurality of image forming units 1Y, 1M, 1C, and 1K that form toner images of the respective color components by an electrophotographic method, and color component toners that are formed by the image forming units 1Y, 1M, 1C, and 1K. The primary transfer unit 10 that sequentially transfers (primary transfer) the image to the intermediate transfer belt 15 and the superimposed toner image transferred onto the intermediate transfer belt 15 are collectively transferred (secondary transfer) to a sheet P that is a recording material (recording paper). ) And a fixing device 60 for fixing the secondary transferred image on the paper P. The image forming apparatus 1 is also provided with a control unit 40 that controls the operation of each part of each device. The fixing device 60 corresponds to an embodiment of a fixing device of the present invention. A combination of the image forming units 1Y, 1M, 1C, and 1K, the primary transfer unit 10, and the secondary transfer unit 20 corresponds to an example of an image forming device according to the present invention.

  The image forming apparatus 1 is a so-called tandem type printer, and the image forming units 1Y, 1M, 1C, and 1K are arranged from the upstream side of the intermediate transfer belt 15 to yellow (Y), magenta (M), cyan (C), They are arranged in one row in the order of black (K). The image forming units 1Y, 1M, 1C, and 1K have the same configuration except that the colors of toners used are different. The image forming unit 1Y, which is responsible for yellow, will be described with reference numerals. The image forming unit 1Y is a charger 12 that charges the photosensitive drum 11 around the photosensitive drum 11 that rotates in the direction of arrow A. And a laser exposure unit 13 for irradiating the photosensitive drum 11 with an exposure beam Bm to write an electrostatic latent image, and developing for developing the electrostatic latent image on the photosensitive drum 11 with toner containing yellow toner. A primary transfer unit 10 for transferring each color component toner image formed on the photosensitive drum 11 to the intermediate transfer belt 15, and a drum cleaner 17 for removing the residual toner on the photosensitive drum 11. Has been.

The intermediate transfer belt 15 is a film-like endless belt made of a material containing an antistatic agent in a resin. As this resin, for example, polyimide or polyamide is used, and as the antistatic agent contained in such a resin, for example, carbon black is used. The volume resistivity of the intermediate transfer belt 15 is 10 ⁶ Ωcm or more and 10 ¹⁴ Ωcm or less, and the thickness thereof is, for example, about 0.1 mm. The intermediate transfer belt 15 is stretched around a plurality of rolls, and moves around in the direction B shown in FIG. The roll on which the intermediate transfer belt 15 is stretched includes a drive roll 31 that drives the intermediate transfer belt 15, a support roll 32 that supports both ends of a region where the intermediate transfer belt 15 extends along the arrangement of the photosensitive drums 11, and These are a tension roll 33 that applies a constant tension to the intermediate transfer belt 15, a backup roll 25 provided in the secondary transfer unit 20, and a cleaning backup roll 34 provided in the cleaning unit 35. The drive roll 31 is driven by a motor (not shown) to move the intermediate transfer belt 15 around at a predetermined speed. The tension roll 33 also functions as a correction roll for preventing the intermediate transfer belt 15 from meandering.

The primary transfer unit 10 includes a primary transfer roll 16 disposed to face the photosensitive drum 11 with the intermediate transfer belt 15 interposed therebetween. The primary transfer roll 16 includes a shaft and a sponge layer as an elastic layer fixed around the shaft. The shaft is a cylindrical bar made of metal, and the metal constituting the shaft is typically iron or SUS (stainless steel). The sponge layer is, for example, a blend rubber in which acrylonitrile-butadiene rubber (NBR), styrene-butadiene rubber (SBR), and ethylene-propylene-diene rubber (EPDM) are blended, and a conductive agent such as carbon black is blended. It is formed of a material having a resistivity of 10 ⁷ Ωcm to 10 ⁹ Ωcm. The intermediate transfer belt 15 is sandwiched between the primary transfer roll 16 and the photosensitive drum 11. The primary transfer roll 16 is applied with a voltage (primary transfer bias) having a polarity opposite to the charging polarity of the toner (in this example, a negative polarity; the same applies hereinafter). As a result, the toner images on the photosensitive drums 11 of the image forming units 1Y, 1M, 1C, and 1K are sequentially electrostatically attracted to the intermediate transfer belt 15 to form a superimposed toner image on the intermediate transfer belt 15. The

The secondary transfer unit 20 includes a secondary transfer roll 22 disposed on the toner image holding surface side of the intermediate transfer belt 15 and a backup roll 25. The backup roll 25 includes an inner layer made of EPDM rubber and a tubular surface layer made of EPDM and NBR blend rubber in which carbon is dispersed. The surface resistivity of the backup roll 25 is 10 ⁷ Ω / m ² or more and 10 ¹⁰ Ω / m ² or less, and the hardness is, for example, about 70 ° (Asker C). The backup roll 25 is disposed on the inner peripheral surface side of the intermediate transfer belt 15, that is, on the opposite side of the secondary transfer roll 22 across the intermediate transfer belt 15, and forms a counter electrode of the secondary transfer roll 22. Yes. The backup roll 25 is in contact with a metal power supply roll 26 to which a secondary transfer bias is applied.

On the other hand, the secondary transfer roll 22 includes a shaft and a sponge layer covering the periphery of the shaft. The shaft is a cylindrical bar made of metal, and the metal constituting the shaft is typically iron or SUS. The sponge layer has a cylindrical shape made of a material in which a conductive agent is blended with a blend rubber. This blend rubber is typically a blend of NBR, SBR, and EPDM, and is blended with the blend rubber. The conductive agent typically is carbon black. The volume resistivity of the sponge layer is 10 ⁷ Ωcm or more and 10 ⁹ Ωcm or less. The secondary transfer roll 22 is pressed against the backup roll 25 with the intermediate transfer belt 15 interposed therebetween. The secondary transfer roll 22 is grounded and forms an electric field due to the secondary transfer bias with the backup roll 25, and the toner image is secondarily transferred onto the paper P conveyed to the secondary transfer unit 20 by this electric field. To do.

  Further, on the downstream side of the secondary transfer portion 20 of the intermediate transfer belt 15, intermediate transfer that cleans the surface of the intermediate transfer belt by removing residual toner and paper dust on the intermediate transfer belt 15 after the secondary transfer. A belt cleaner 35 is provided. On the other hand, on the upstream side of the yellow image forming unit 1Y, a reference sensor (home position sensor) 42 for generating a reference signal for taking an image forming timing in each of the image forming units 1Y, 1M, 1C, 1K is disposed. Has been. The reference sensor 42 recognizes a mark provided on the back side of the intermediate transfer belt 15 and generates a reference signal. In response to an instruction from the control unit 40 based on the recognition of the reference signal, each of the image forming units 1Y and 1M. , 1C, 1K start image formation. Further, an image density sensor 43 for adjusting image quality is disposed downstream of the black image forming unit 1K.

  Further, the image forming apparatus 1 includes, as a paper transport system, a paper storage unit 50 that stores the paper P, a pickup roll 51 that feeds the paper P accumulated in the paper storage unit 50 at a predetermined timing, and a pickup roll. The secondary transfer roll 22 is secondary-transferred by a transport roll 52 that transports the paper P fed by 51, a guide member 53 that guides the paper P transported by the transport roll 52 to the secondary transfer unit 20, and the secondary transfer roll 22. A conveyance belt 55 that conveys the subsequent paper P to the fixing device 60 and a fixing entrance guide 56 that guides the paper P to the fixing device 60 are provided.

  The fixing device 60 includes a fixing roll 61 and an endless belt 62. The fixing roll 61 is heated and rotated. The endless belt 62 moves following the fixing roll 61. The fixing roll 61 and the endless belt 62 fix the unfixed toner image on the paper P by heating and pressurizing the paper P with the paper P interposed therebetween. A more detailed configuration of the fixing device 60 will be described later.

  Next, a basic image forming process of the image forming apparatus 1 will be described.

  In the image forming apparatus 1, image data output from a personal computer (PC) (not shown) is subjected to image processing by an image processing apparatus (not shown), and then image forming units 1Y, 1M, 1C, Supplied to 1K. In the image processing apparatus, various kinds of image processing such as shading correction, position shift correction, brightness / color space conversion, gamma correction, frame deletion, color editing, and movement editing are performed on the input reflectance data. The image data subjected to the image processing is converted into color material gradation data of four colors Y, M, C, and K, and supplied to the laser exposure unit 13 of the image forming units 1Y, 1M, 1C, and 1K.

  The laser exposure unit 13 irradiates, for example, an exposure beam Bm emitted from a semiconductor laser to the photosensitive drums 11 of the image forming units 1Y, 1M, 1C, and 1K according to the supplied color material gradation data. . In each of the photosensitive drums 11 of the image forming units 1Y, 1M, 1C, and 1K, the surface is charged by the charger 12, and then the surface is scanned and exposed by the laser exposure unit 13 to form an electrostatic latent image. The formed electrostatic latent images are developed as toner images of respective colors Y, M, C, and K by the developing devices 14 of the respective image forming units 1Y, 1M, 1C, and 1K. The toner images formed on the photosensitive drums 11 of the image forming units 1Y, 1M, 1C, and 1K are transferred onto the intermediate transfer belt 15 in the primary transfer unit 10 where the photosensitive drums 11 and the intermediate transfer belt 15 are in contact with each other. Is done. More specifically, in the primary transfer unit 10, a voltage (primary transfer bias) having a polarity opposite to the toner charging polarity (minus polarity) is applied to the intermediate transfer belt 15 by the primary transfer roll 16, so that the toner image is formed. The toner image is transferred onto the surface of the intermediate transfer belt 15. The toner images formed by the image forming units 1Y, 1M, 1C, and 1K are sequentially superimposed on the surface of the intermediate transfer belt 15.

  The toner images are sequentially transferred to the surface of the intermediate transfer belt 15 and then conveyed to the secondary transfer unit 20 as the intermediate transfer belt 15 moves. On the other hand, in the paper transport system, the pickup roll 51 rotates in accordance with the timing at which the toner image is transported to the secondary transfer unit 20 and feeds the paper P stored in the paper storage unit 50. The paper P fed out by the pickup roll 51 is transported by the transport roll 52 and reaches the secondary transfer unit 20 through the guide member 53. Before reaching the secondary transfer unit 20, the paper P is temporarily stopped, and the registration roller (not shown) rotates in accordance with the movement timing of the intermediate transfer belt 15 on which the toner image is held. And the position of the toner image are matched.

  In the secondary transfer unit 20, the secondary transfer roll 22 presses the intermediate transfer belt 15 against the backup roll 25. The conveyed paper P is sandwiched between the intermediate transfer belt 15 and the secondary transfer roll 22. A voltage (secondary transfer bias) having the same polarity as the toner charging polarity (minus polarity) is applied from the power supply roll 26 to the backup roll 25, and a transfer electric field is formed between the secondary transfer roll 22 and the backup roll 25. Is done. The toner image held on the intermediate transfer belt 15 is electrostatically transferred from the intermediate transfer belt 15 onto the paper P.

  Thereafter, the sheet P on which the toner image is electrostatically transferred is peeled off from the intermediate transfer belt 15 by the secondary transfer roll 22 and conveyed, and the conveyance belt 55 provided on the downstream side of the secondary transfer roll 22 in the sheet conveyance direction. It is conveyed to. The conveyance belt 55 conveys the paper P to the fixing device 60 in accordance with the conveyance speed of the fixing device 60. The toner image on the paper P conveyed to the fixing device 60 is fixed on the paper P by being subjected to a fixing process by heat and pressure by the fixing device 60. The paper P on which the fixed image is formed is conveyed to a paper discharge unit (not shown) provided in the discharge unit of the image forming apparatus.

On the other hand, the residual toner remaining on the intermediate transfer belt 15 that could not be transferred from the intermediate transfer belt 15 to the paper P in the secondary transfer unit 20 is conveyed to the cleaning unit as the intermediate transfer belt 15 moves, and the cleaning backup roll 34. The intermediate transfer belt cleaner 35 is removed from the intermediate transfer belt 15.
[Fixing device]
Here, the fixing device 60 constituting the image forming apparatus 1 shown in FIG. 1 will be described. The fixing device 60 is an embodiment of the fixing device of the present invention.

  FIG. 2 is a cross-sectional view showing the configuration of the fixing device 60.

  A fixing device 60 shown in FIG. 2 includes a fixing roll 61, an endless belt 62, and a pressure pad 64 that presses the endless belt 62 against the fixing roll 61.

  The fixing device 60 is a so-called free belt type fixing device, and is a device aiming at further miniaturization, energy saving and high speed in the roll / belt type fixing device. The fixing device 60, which is a free belt type fixing device, does not have a support roll or a pressure roller for stretching the endless belt 62, and is supported by the belt guide member 63 so as to be capable of circular movement. Further, the endless belt 62 is driven by receiving a driving force from the fixing roll 61. Such a roll / belt type fixing device is free to be distinguished from a type having a support roll and a pressure roll. This is called a belt type fixing device.

  The fixing roll 61 is a cylindrical roll in which a heat-resistant elastic body layer 612 and a release layer 613 are laminated around a metal core (cylindrical cored bar) 611, and is rotatably supported by the fixing device 60 main body. Has been. The fixing roll 61 corresponds to the first embodiment of the release member of the present invention, and also corresponds to an example of the sandwiching member according to the present invention. The fixing roll 61 is a so-called straight roll having a uniform outer diameter in a direction along the rotation axis. The outer peripheral surface 61 a of the fixing roll 61 moves around as the fixing roll 61 rotates. The moving speed of the outer peripheral surface 61a is, for example, 194 mm / sec.

  Inside the fixing roll 61, for example, a halogen heater 66 having a rating of 600 W is disposed as a heat source. The halogen heater 66 corresponds to an example of a heater according to the present invention. On the other hand, a temperature sensor 69 is provided outside the fixing roll 61, and the temperature sensor 69 is in contact with the outer peripheral surface of the fixing roll 61. The control unit 40 (see FIG. 1) of the image forming apparatus controls lighting of the halogen heater 66 based on the temperature measurement value by the temperature sensor 69, and sets the outer peripheral temperature of the fixing roll 61 to a predetermined temperature (for example, 175). ° C).

  The endless belt 62 is a belt-like belt that is endless in the direction of circular movement, and is formed seamlessly in order to prevent defects in the output image. The endless belt 62 corresponds to the second embodiment of the release member of the present invention, and also corresponds to an example of the sandwiching member according to the present invention. The endless belt 62 is supported by a pressure pad 64 and a belt guide member 63 disposed inside the endless belt 62 so as to freely move around. In the nip portion N, the endless belt 62 is in contact with the fixing roll 61 and the outer peripheral surface, and moves around as the fixing roll 61 rotates. More specifically, the endless belt 62 is disposed so as to come into contact with the fixing roll 61 under pressure, and is driven by the fixing roll 61 at a predetermined speed (for example, 194 mm / sec). Move around.

  Further, a separation assisting member 70 that completely separates the sheet P separated from the fixing roll 61 from the fixing roll 61 is disposed downstream of the nip portion N of the fixing device 60. The peeling auxiliary member 70 extends toward the fixing roll 61 in a direction (counter direction) in which the peeling baffle 71 held by the baffle holder 72 faces the moving direction of the outer peripheral surface of the fixing roll 61, and the leading end of the peeling auxiliary member 70 is the same as the fixing roll 61. It is arranged at a close position.

[Basic operation of fixing device]
Here, the basic operation of the fixing device 60 will be described before a detailed description of each member. The fixing roll 61 is connected to a drive motor (not shown) and rotates in the direction of arrow C. The endless belt 62 is driven by the fixing roll 61 and has the same direction as the outer peripheral surface of the fixing roll 61 moves at the nip portion N. Move to. The sheet P on which the toner image is electrostatically transferred in the secondary transfer unit 20 (see FIG. 1) of the image forming apparatus 1 is guided by the fixing inlet guide 56 and conveyed to the nip N. When the paper P passes through the nip portion N, the toner image on the paper P is fixed on the paper P by the heat supplied from the fixing roll 61 and the pressure sandwiched between the fixing roll 61 and the endless belt 62. The In the fixing device 60, since the pre-nip member 64a has a concave shape, the nip portion N is secured wider than in the case of a flat shape, for example, and heat and pressure are applied for a long time, so that the fixing performance is stabilized. .

  The time (nip time) for the paper P to pass through the nip portion N is desirably 0.030 seconds or more. If this nip time is smaller than 0.030 seconds, it is difficult to achieve both good fixing properties and prevention of paper wrinkles and curling. Therefore, it is necessary to raise the fixing temperature accordingly, wasting energy, It is not preferable because durability is lowered and the temperature of the apparatus is increased. The upper limit of the nip time is not particularly limited, but is preferably 0.5 seconds or less in view of the balance between the fixing processing capability and the size of the apparatus and members.

  The paper P that has passed through the nip portion N is peeled off from the fixing roll 61 and guided to the paper discharge path by the peeling auxiliary member 70.

[Configuration of Each Member in Fixing Device]
Next, each member constituting the fixing device 60 will be described.

  FIG. 3 is a configuration diagram of the fixing roll 61.

  The core 611 of the fixing roll 61 is a cylindrical body formed of a metal, an alloy, or a ceramic having high thermal conductivity, typically iron, aluminum (for example, A-5052 material), SUS, copper, or the like. Is, for example, an outer diameter of 30 mm, a wall thickness of 1.8 mm, and a length of 360 mm.

  The heat resistant elastic body layer 612 is formed of an elastic body having a high heat resistance enough to withstand the temperature at the time of fixing. As this elastic body, for example, the rubber hardness is 15 ° to 45 ° (JIS-A). The rubber or elastomer is used. For the heat-resistant elastic layer 612, it is preferable to use silicone rubber, fluorine rubber or the like excellent in heat resistance, and it is particularly preferable to use silicone rubber. Examples of the silicone rubber include RTV silicone rubber, HTV silicone rubber, and liquid silicone rubber. Specifically, polydimethyl silicone rubber (MQ), methyl vinyl silicone rubber (VMQ), methyl phenyl silicone rubber (PMQ). ), Fluorosilicone rubber (FVMQ) and the like. Various additives may be blended. Examples of additives include reinforcing agents (carbon black, etc.), fillers (calcium carbonate, etc.), softeners (paraffins, etc.), processing aids (stearic acid, etc.), anti-aging agents (amines, etc.), additives Examples include sulfurizing agents (sulfur, metal oxides, peroxides, etc.), functional fillers (alumina, etc.), and the like.

  In the fixing device 60 of the present embodiment, an HTV silicone rubber having a rubber hardness of 35 ° (JIS-A) is coated on the core 611 with a thickness of 600 μm. The thickness of the heat resistant elastic layer 612 is usually 3 mm or less, and preferably in the range of 0.1 mm or more and 1.5 mm or less. The method for forming the heat-resistant elastic layer 612 around the core 611 is not limited to a specific method, and for example, a known coating method or molding can be employed.

  A combination of the core 611 and the heat-resistant elastic body layer 612 of the fixing roll 61 corresponds to an example of the base layer referred to in the present invention.

  Since the release layer 614 is laminated on the outer peripheral surface of the heat resistant elastic layer 612 of the fixing roll 61 with the adhesive layer 613 interposed therebetween, an offset phenomenon in which the toner image adheres to the outer peripheral surface of the fixing roll 61 is avoided. Is done. The adhesive layer 613 corresponds to an example of an adhesive layer according to the present invention, and the release layer 614 corresponds to an example of a release layer according to the present invention. Although details of the adhesive layer 613 will be described later, in the adhesive layer 613, particles 613a functioning as a heat resistance improver for improving the heat resistance of the adhesive layer 613 are blended.

  The thickness of the release layer 614 is usually 10 μm or more and 50 μm or less, preferably 15 μm or more and 30 μm or less. As a material for the release layer 613, from the viewpoint of heat resistance and toner release properties, tetrafluoroethylene / perfluoroalkyl vinyl ether copolymer (PFA), polytetrafluoroethylene (PTFE), tetrafluoroethylene-hexafluoropropylene. Copolymers (FEP), polyethylene tetrafluoroethylene (ETFE), polyvinylidene fluoride (PVDF), polychlorotrifluoride ethylene (PCTFE), vinyl fluoride (PVF), etc. are used, but tetrafluoroethylene / perfluoro Any material of an alkyl vinyl ether copolymer or a tetrafluoroethylene-hexafluoropropylene copolymer is preferable.

  Next, the configuration of the endless belt 62 shown in FIG. 2 will be described. The endless belt 62 is formed seamlessly so that no defect occurs in the output image.

  FIG. 4 is a configuration diagram of the endless belt 62.

  The endless belt 62 includes a base layer 621, an elastic layer 622 provided on the outer peripheral surface side of the base layer 621, a release layer (surface layer) 624 covering the outer peripheral surface side of the elastic layer 622, a release layer The adhesive layer 623 is formed by adhering the layer 624 to the outer peripheral surface of the elastic layer 622.

  A combination of the base layer 621 and the elastic layer 622 of the endless belt 62 corresponds to an example of the base layer of the present invention. The adhesive layer 623 corresponds to an example of the adhesive layer according to the present invention, and the release layer 624 corresponds to an example of the release layer according to the present invention.

  For the base layer 621, one or a mixture selected from a thermosetting polyimide resin, a thermoplastic polyimide resin, a polyamide resin, a polyamideimide resin, a polybenzimidazole resin, and the like is preferable from the viewpoint of heat resistance and mechanical properties. Used for.

  For the elastic layer 622, it is preferable to use silicone rubber, fluorine rubber, or the like excellent in heat resistance, and it is particularly preferable to use silicone rubber. Examples of the silicone rubber include RTV silicone rubber, HTV silicone rubber, and liquid silicone rubber. Specifically, polydimethyl silicone rubber (MQ), methyl vinyl silicone rubber (VMQ), methyl phenyl silicone rubber (PMQ). ), Fluorosilicone rubber (FVMQ) and the like. Various additives may be blended. Examples of additives include reinforcing agents (carbon black, etc.), fillers (calcium carbonate, etc.), softeners (paraffins, etc.), processing aids (stearic acid, etc.), anti-aging agents (amines, etc.), additives Examples include sulfurizing agents (sulfur, metal oxides, peroxides, etc.), functional fillers (alumina, etc.), and the like.

  The thickness of the release layer 624 is usually 5 μm or more and 100 μm or less, preferably 10 μm or more and 30 μm or less. As the material of the release layer 623, like the release layer 614 of the fixing roll 61 described above, from the viewpoint of heat resistance and toner release properties, tetrafluoroethylene / perfluoroalkyl vinyl ether copolymer (PFA), poly Tetrafluoroethylene (PTFE), tetrafluoroethylene-hexafluoropropylene copolymer (FEP), polyethylene-tetrafluoroethylene (ETFE), polyvinylidene fluoride (PVDF), polychlorotrifluorinated ethylene (PCTFE), vinyl fluoride ( PVF) or the like is used, and any material of a tetrafluoroethylene / perfluoroalkyl vinyl ether copolymer or a tetrafluoroethylene-hexafluoropropylene copolymer is preferable.

  The release layer 624 is once formed as an endless belt using a mold. Then, the elastic layer 622 is covered with the above-described elastic layer 622 and bonded to the elastic layer 622 with an adhesive layer 623. At this time, it is desirable that the inner peripheral surface of the release layer 624 be subjected to a surface treatment for improving the adhesion with the adhesive layer 623.

  Details of the adhesive layer 623 will be described later together with details of the adhesive layer 613 of the fixing roll 61. In the adhesive layer 623, particles 623a functioning as a heat resistance improver for improving the heat resistance of the adhesive layer 623 are included. It is blended.

  Returning to FIG. 2, the description of each member constituting the fixing device 60 will be continued.

  The pressure pad 64 presses the endless belt 62 against the fixing roll 61 with a load of, for example, 343 N (35 kgf). For the pre-nip member 64a and the peeling nip member 64b of the pressure pad 64, a material having a JIS-A hardness of 10 ° or more and 40 ° or less is usually used, but a material having a hardness outside this range can also be used. The pre-nip member 64a is, for example, silicone rubber having a width of 5 mm, a thickness of 5 mm, and a length of 320 mm. However, as a material for the pre-nip member 64a, an elastic body such as fluoro rubber, a leaf spring, or the like can be employed in addition to the silicone rubber. The surface of the pre-nip member 64a facing the fixing roll 61 is formed in a concave shape.

  The peeling nip member 64b is formed of a heat-resistant resin such as PPS, polyimide, polyester, or polyamide, or a metal such as iron, aluminum, or SUS. A surface of the peeling nip member 64b facing the fixing roll 61 is formed as a convex curved surface having a substantially constant radius of curvature.

  The endless belt 62 pressed against the fixing roll 61 by the pressure pad 64 is wound around the fixing roll 61 at a winding angle of about 25 ° to form a nip portion N. The length of the nip portion N in the sheet conveyance direction (nip The width is about 6 mm.

[Adhesive layer]
Here, details of the adhesive layer 613 of the fixing roll 61 and the adhesive layer 623 of the endless belt 62 will be described. Here, the two adhesive layers 613 and 623 will be described without particular distinction.

Each of the adhesive layers 613 and 623 is obtained by curing an adhesive composition containing the following components (a) to (f).
(A) Organopolysiloxane containing at least two alkenyl groups directly bonded to a silicon atom in one molecule (b) Organohydrogenpolysiloxane containing at least two hydrogen atoms directly bonded to a silicon atom (c) ) Platinum or platinum-based compound (d) Adhesion imparting component (e) Heat resistance improver (particle) having an average particle size of 10 μm or less
(F) Reaction control agent The component (a) is a base polymer of an adhesive and is preferably represented by the following average composition formula (1).

R _1a SiO _{(4-a) / 2} (1)
(In the formula, R ₁ is an unsubstituted or substituted monovalent hydrocarbon group, and a is preferably in the range of 1.5 to 2.8.)
Examples of R ₁ include alkyl groups such as methyl, ethyl, propyl, isopropyl, butyl, isobutyl, pentyl, neopentyl, hexyl, cyclohexyl, octyl, nonyl, decyl, Aryl group such as phenyl group, tolyl group, xylyl group, naphthyl group, aralkyl group such as benzyl group, phenylethyl group, phenylpropyl group, vinyl group, allyl group, propenyl group, isopropenyl group, butenyl group, hexenyl group, Alkenyl groups such as cyclohexenyl group, octenyl group, etc., and those in which some or all of the hydrogen atoms are substituted with halogen atoms such as fluorine, bromine, chlorine, cyano groups, etc., such as chloromethyl group, chloropropyl group , Bromoethyl group, trifluoropropyl group, cyanoethyl group and the like. In this case, at least two of R ₁ need to be alkenyl groups. This alkenyl group may be bonded to a silicon atom at the end of the molecular chain, may be bonded to a silicon atom in the middle of the molecular chain, or may be bonded to both.

  The organohydrogenpolysiloxane containing two or more hydrogen atoms bonded to silicon atoms, which is the component (b), is a crosslinking agent for the component (a). This organohydrogenpolysiloxane is preferably one represented by the following average composition formula (2).

R _2b H _c SiO _{(4-b-c) / 2} (2)
(In the formula, R ₂ is an unsubstituted or substituted monovalent hydrocarbon group, b is 1.0 or more and 2.0 or less, c is 0.01 or more and 1.0 or less, and b + c is 1.5 or more. It is preferably in the range of 2.5 or less.)
Examples of R ₂ include those similar to R ₁ , but those having no aliphatic unsaturated bond are preferred, and alkyl groups and phenyl groups are preferred.

Specific examples of such organohydrogenpolysiloxanes include 1,1,3,3-tetramethyldisiloxane, 1,3,5,7-tetramethylcyclotetrasiloxane, methylhydrogencyclopolysiloxane, methylhydrogen. Gensiloxane / dimethylsiloxane cyclic copolymer, tris (methylhydrogensiloxy) methylsilane, tris (methylhydrogensiloxy) phenylsilane, trimethylsiloxy group-blocked methylhydrogenpolysiloxane, trimethylsiloxy group-blocked dimethylsiloxane at both ends Methylhydrogensiloxane copolymer, dimethylhydrogensiloxy group-capped dimethylpolysiloxane at both ends, dimethylhydrogensiloxy group-capped dimethylsiloxane / methylhydride at both ends Siloxane copolymers, both end trimethylsiloxy-blocked methylhydrogensiloxane-diphenylsiloxane copolymers, both end trimethylsiloxy-blocked methylhydrogensiloxane phen diphenylsiloxane-dimethylsiloxane copolymer, (CH _{3) 2} HSiO _{1 / 2} unit and SiO _4/2 unit copolymer, (CH ₃ ) ₂ HSiO _1/2 unit, SiO _4/2 unit and (C ₆ H ₅ ) ₃ SiO _3/2 unit Copolymers, copolymers comprising (CH ₃ ) ₂ HSiO _1/2 units, (CH ₃ ) ₃ SiO _1/2 units and SiO _4/2 units, and some or all of the methyl groups in these exemplary compounds Substituted with an aryl group such as phenyl group or other alkyl group or propyl group

  The component (c) is a reaction catalyst for the component (a) and the component (b). Examples of platinum or platinum-based compounds used as the component (c) include platinum black, second platinum chloride, platinum chloride. Examples thereof include acids, reaction products of chloroplatinic acid and monohydric alcohols, complexes of chloroplatinic acid and olefins, and platinum bisacetoacetate.

  As the adhesion-imparting agent for the component (d), those known for use in addition-curable silicone rubber compositions are used. Particularly, a trialkoxysilyl group, an organodialkoxysilyl group, a diorgano in one molecule. Alkoxysilyl groups such as alkoxysilyl groups, silanol groups, carbinol groups, epoxy groups, hydrogen atoms bonded to silicon atoms, alkenyl groups bonded to silicon atoms, aliphatic unsaturated groups such as alkynyl groups, amino groups, esters A silane having two or more functional groups selected from the group is used. Among these silanes, a silane having a hydrogen atom bonded to at least one of an alkoxysilyl group and a silicon atom and one or more other functional groups is preferable. For example, vinyltrimethoxysilane, vinyltriethoxysilane, allyltrimethoxysilane, allyltriethoxysilane, γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropyltriethoxysilane, aminopropyltrimethoxysilane, etc. Examples include (alkoxy) silanes, various siloxane compounds having a hydrogen atom bonded to a silicon atom, and one or more other functional groups such as an epoxy group and an alkoxysilyl group.

  The heat resistance improver for the component (e) can be selected from known materials, and organic materials such as butylated hydroxytoluene and hindered amine, fumed silica, precipitated silica, diatomaceous earth, ground quartz, There are inorganic types such as titanium oxide, diiron trioxide, triiron tetroxide, cerium oxide, zinc oxide, carbon black, etc., but inorganic types are preferred, and triiron tetroxide is particularly preferred from the viewpoint of extending the life. preferable.

  In general, it is considered that particles blended in the adhesive layer for the purpose of a heat resistance improver have a particle size larger than 10 μm, and that a larger particle size contributes to an improvement in heat resistance. However, as the heat resistance improver for the component (e), those having a small particle size having a particle size of 10 μm or less are used. Inventors have found that, by blending particles with a small particle size as a heat resistance improver, adhesion durability during heating is improved contrary to conventional prediction.

  As the reaction control agent for the component (f), triallyl isocyanurate, alkyl maleate, acetylene alcohols and their silane or siloxane modified products, 1-ethynyl-1-cyclohexanol, hydroperoxide, tetramethylethylenediamine and benzoate And triazole.

  Each of the adhesive layers 613 and 623 is a known coating method such as spraying, brushing, dipping, ring coating, blade coating, roll transfer, etc., using such an adhesive composition containing the components (a) to (f). It is formed by applying and curing. About this adhesive composition, solid content ratio and a viscosity may be adjusted with an organic solvent etc. Further, when the adhesive composition is cured, it may be dried as necessary.

Further, the adhesive composition for forming each of the adhesive layers 613 and 623 includes, as component (g), R ₃ SiO _1/2 unit (R ₃ is an unsubstituted or substituted monovalent unit price hydrogen group) and SiO _2. It is preferable to contain a resinous copolymer having a unit as a main component and a molar ratio of R ₃ SiO _1/2 units to SiO ₂ units of 0.5 to 1.5. This component (g) is a crosslinking agent that causes three-dimensional crosslinking, and corresponds to an example of the crosslinking agent referred to in the present invention. The combined use of such a crosslinking agent and the above-described heat resistance improver having a small particle diameter results in a three-dimensional reinforcing structure and improves the strength of the adhesive layer.

  In the description of the above embodiment, an example of a so-called fixing member incorporated in the fixing device is shown as an embodiment of the releasing member of the present invention. However, the releasing member of the present invention is limited to the fixing member. For example, a transfer roll or a transfer belt may be used.

  In the above description, the embodiment of the fixing device in which both the fixing roll, which is the first embodiment of the release member, and the endless belt, which is the second embodiment of the release member, is described. In the fixing device and the image forming apparatus, the embodiment of the release member may be applied to only one of the fixing roll and the endless belt.

  Further, the embodiment of the fixing device described above is a so-called free belt type fixing device, but the fixing device of the present invention may be another type of roll / belt type fixing device, or may be a roll / roll type. It may be a fixing device or a belt-belt type fixing device.

[Example]
Hereinafter, based on an Example, embodiment is described more concretely. In addition, embodiment of this invention is not limited to the Example demonstrated below.

  In comparison with an image forming apparatus (Fuji Xerox DocuCentre C6550I) having a fixing device having the same configuration as the roll / belt type fixing device 60 shown in FIG. It was prepared and a paper passing test was conducted, and the life until peeling occurred was confirmed. The paper used was J paper (manufactured by Fuji Xerox).

Example 1
An elastic layer made of silicone rubber having a hardness of A / 33 was formed on a metal core having an outer diameter of 35 mm and a length of 415 mm with a thickness of 600 μm. The adhesive layer has a side chain vinyl group-containing dimethylpolysiloxane having a main chain composed of dimethylsiloxane units and methylvinylsiloxane units, and both ends of the molecular chain blocked with trimethylsiloxy groups (polymerization degree 700, vinyl value 0). 0.025 mol / 100 g) 100 parts by mass, 20 parts by mass of ferric trioxide having an average particle diameter of 5 μm, 10 parts by mass of cerium oxide having an average particle diameter of 9 μm, 50 parts by mass of γ-glycidoxypropyltrimethoxysilane, organohydrogenpoly 80 parts by mass of siloxane, 30 parts by mass of methylhydrogenpolysiloxane having a Si—H group at both ends and side chains (polymerization degree 17, Si—H group amount 0.0030 mol / g), 0.1% by mass of ethynylcyclohexanol Part and 0.1 parts by mass of chloroplatinic acid were formed to a thickness of 10 μm. A fluororesin layer tube made of a tetrafluoroethylene / perfluoroalkyl vinyl ether copolymer having an excimer laser treatment on the back surface was prepared. A fluororesin tube was coated on the adhesive layer and baked at 200 ° C. for 4 hours in a hot air oven to obtain the fixing roll of Example 1.

(Example 2)
A fixing member of Example 2 was obtained in the same manner as Example 1 except that the average particle size of ferric trioxide was 9 μm.

(Example 3)
A fixing member of Example 3 was obtained in the same manner as in Example 1 except that triiron tetroxide having an average particle diameter of 5 μm was used as the heat resistance improver.

Example 4
A fixing member of Example 4 was obtained in the same manner as in Example 3 except that triiron tetroxide having an average particle diameter of 9 μm was used as the heat resistance improver.

(Example 5)
Furthermore, a resinous copolymer [{(CH ₃ ) ₃ SiO _1/2 unit comprising (CH ₃ ) ₃ SiO _1/2 units and CH ₂ = CH (CH ₃ ) ₂ SiO _1/2 units and SiO ₂ units] + CH ₂ = CH (CH ₃ ) ₂ SiO _1/2 unit} / SiO ₂ unit (molar ratio) = 0.8, vinyl group content = 0.0005 mol / g], except that 80 parts by mass were contained. The fixing member of Example 5 was obtained in the same manner as Example 4.

(Comparative Example 1)
A fixing member of Comparative Example 1 was obtained in the same manner as in Example 1 except that ferric trioxide and cerium oxide having an average particle diameter of 11 μm were used as the heat resistance improver.

(Comparative Example 2)
A fixing member of Comparative Example 2 was obtained in the same manner as in Example 1 except that the heat resistance improver was not included.

(Comparative Example 3)
A fixing member of Comparative Example 3 was obtained in the same manner as in Example 1 except that only ferric trioxide having an average particle diameter of 11 μm was used as the heat resistance improver.

(Comparative Example 4)
A fixing member of Comparative Example 4 was obtained in the same manner as in Example 1 except that only triiron tetroxide having an average particle diameter of 11 μm was used as the heat resistance improver.

(Comparative Example 5)
A fixing member of Comparative Example 5 was obtained in the same manner as in Example 1 except that only ferric trioxide having an average particle diameter of 15 μm was used as the heat resistance improver.

  The results of paper passing tests conducted on these examples and comparative examples are summarized in Table 1 below.

  In Example 1 and Example 2, when the number of sheets passed reached 800,000, the release layer peeled off from the adhesive layer, and a sufficient life as the fixing roll was obtained. That is, since it was confirmed that the fixing rolls of Example 1 and Example 2 have sufficiently high durability as adhesive durability under heating, the evaluation was “◯”.

  In Examples 3 and 4, the service life was longer, and the release layer peeled off from the adhesive layer when the number of sheets passed reached 1.5 million. A comparison between Examples 1 and 2 and Examples 3 and 4 shows that the use of triiron tetroxide has a longer life than that of ferric trioxide as a heat resistance improver, that is, the durability of adhesion under heating is longer. Since it was confirmed that it was further improved, the evaluation was “◎”. Generally, ferric trioxide is considered to be superior to triiron tetroxide as a heat resistance improver. However, when used with a small particle size of 10 μm or less, the tetraoxide is rather It has been found that ferrous iron is preferred.

  For Example 5, the life was longer than that of Examples 3 and 4, and even when the number of sheets passed reached 1.5 million, the release layer did not peel off from the adhesive layer. It was. A comparison between Examples 3 and 4 and Example 5 confirmed that the addition of a cross-linking agent that causes three-dimensional cross-linking increases the life, i.e., improves the durability of adhesion under heating. .

  On the other hand, in Comparative Example 1, the release layer peeled off from the adhesive layer when the number of sheets passed reached 400,000, and the life of the fixing roll was insufficient, so the evaluation was “x”. .

  Further, in Comparative Example 2, the release layer peeled off from the adhesive layer when the number of sheets passed reached 100,000, and the life of the fixing roll was completely insufficient, so the evaluation was “XX”. It was.

  Furthermore, also in Comparative Example 3 and Comparative Example 4, the release layer peeled off from the adhesive layer when the number of sheets passed reached 400,000, and the life of the fixing roll was insufficient. × ”.

  In Comparative Example 5, the release layer was peeled off from the adhesive layer when the number of sheets passed reached 300,000, and the life of the fixing roll was insufficient, so the evaluation was “x”.

  According to comparison between Comparative Examples 1, 3, 4, 5 and Examples 1 and 2, when the particle size of the heat resistance improver exceeds 10 μm, the life of the fixing roll is increased regardless of the type of the heat resistance improver. It was confirmed that it was greatly reduced. That is, it was confirmed that the basic effect (improvement of adhesion durability under heating) can be obtained when the particle size of the heat resistance improver is 10 μm or less regardless of the type of the heat resistance improver.

DESCRIPTION OF SYMBOLS 1 Image forming apparatus 60 Fixing apparatus 61 Fixing roll 611 Core 612 Heat resistant elastic body layer 613 Adhesive layer 614 Release layer 62 Endless belt 621 Base layer 622 Elastic layer 623 Adhesive layer 624 Release layer (surface layer)

Claims (5)

The base layer,
A release layer having a surface exhibiting a release property higher than the release property exhibited by the surface of the base layer;
An adhesive layer that is sandwiched between the base layer and the release layer and adheres the base layer and the release layer, and has an average particle size of 10 μm or less and improves the heat resistance of the adhesive layer. An adhesive layer formulated with
A release member characterized by comprising:   The mold release member according to claim 1, wherein the adhesive layer contains triiron tetroxide particles as the heat resistance improving particles.   3. The release member according to claim 1, wherein the adhesive layer is blended with the heat resistance improving particles and a crosslinking agent that causes three-dimensional crosslinking. 4. The base layer,
A release layer having a surface exhibiting a release property higher than the release property exhibited by the surface of the base layer;
An adhesive layer that is sandwiched between the base layer and the release layer and adheres the base layer and the release layer, and has an average particle size of 10 μm or less and improves the heat resistance of the adhesive layer. An adhesive layer formulated with
A release member comprising:
A recording medium on which a non-fixed image is formed is sandwiched between the release member and the recording medium passes between the release member; and the release member and the A heater for heating the recording medium passing between the sandwiching members;
A fixing device comprising: An image forming device for forming an unfixed image on the surface of the recording medium;
A fixing device for fixing an unfixed image on the recording medium on the recording medium,
The fixing device is
The base layer,
A release layer having a surface exhibiting a release property higher than the release property exhibited by the surface of the base layer;
An adhesive layer that is sandwiched between the base layer and the release layer and adheres the base layer and the release layer, and has an average particle size of 10 μm or less and improves the heat resistance of the adhesive layer. An adhesive layer formulated with
A release member comprising:
A recording medium on which a non-fixed image is formed is sandwiched between the release member and the recording medium passes between the release member; and the release member and the A heater for heating the recording medium passing between the sandwiching members;
An image forming apparatus comprising:

Images