JP2009103882A - Pressure member, image heating device, and image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a pressure member which comes into contact with a heating member and forms a nip part for heating while holding and conveying recording material, moderates excessive temperature rise in an area through which the recording material does not pass, and improves durability performance and conveyance property of the recording material. <P>SOLUTION: The pressure member 24 which comes into contact with the heating member 23 and forms the nip part N for heating while holding and conveying the recording material P is equipped with filler 24f having heat conduction anisotropy in the filler between a releasing layer 24c and an elastic layer 24a. The filler is bound by an adhesive for sticking the releasing layer and the elastic layer. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a pressure member suitable for use in an image forming apparatus such as an electrophotographic copying machine or an electrophotographic printer (fixing device), an image heating apparatus having the pressure member, and the image heating apparatus. The present invention relates to an image forming apparatus.

  As a fixing device (fixing device) mounted on an electrophotographic printer or copying machine, a halogen heater, a fixing roller heated by the halogen heater, and a pressure roller that contacts the fixing roller to form a nip portion , There is a heat roller type. Further, as a fixing device (fixing device), a heater having a heating resistor on a ceramic substrate, a fixing film that moves while being in contact with the heater, and a heater and a nip portion that are formed through the fixing film are formed. There is a film heating type having a pressure roller. Both the heat roller type and film heating type fixing devices heat and fix a toner image on a recording material while nipping and conveying a recording material carrying an unfixed toner image at a nip portion.

  When a small-size recording material is continuously printed at the same print interval as a large-size recording material in a printer equipped with the above-described heat roller type fixing device, an area where the recording material does not pass on the fixing roller (non-sheet passing area) is excessive. It is known to raise the temperature. In addition, when a small-size recording material is continuously printed at the same print interval as a large-size recording material in a printer equipped with the above-described film heating type fixing device, an area where the recording material does not pass through the heater (non-sheet passing area) is excessive. It is known that the temperature rises. If the temperature of the non-sheet passing area of the fixing roller or the non-sheet passing area of the heater is excessively increased, there is a possibility that each part constituting the fixing device is damaged. Further, if printing is performed on a large-size recording material in a state where the temperature of the non-sheet passing region is excessively high, the toner is excessively melted at a portion corresponding to the non-sheet passing region in the recording material, and a high temperature offset occurs.

  In particular, in the case of a film heating type fixing device, since the heat capacity of the heater is smaller than that of a heat roller type fixing device, the temperature rise in the non-sheet passing region of the heater is also large. Therefore, the durability performance of the pressure roller is reduced, and high temperature offset is likely to occur. Further, the rotational driving of the film becomes unstable, or the film is twisted and wrinkles are easily generated on the film.

  Further, as the printer processing speed (process speed) increases, the temperature rise in the non-sheet passing area is likely to occur. This is because the time required for the recording material to pass through the nip portion is shortened as the speed is increased, and the fixing temperature necessary to heat-fix the toner image on the recording material must be increased. Also, during the continuous printing process, the time during which the recording material does not intervene in the nip portion (so-called paper interval time) decreases as the speed of the printer increases, so it becomes difficult to equalize the temperature distribution unevenness during the paper interval time. It is.

  As one of means for reducing the temperature increase of the non-sheet passing portion where the non-sheet passing region overheats as described above, a method of increasing the thermal conductivity of the pressure roller is generally known. This is because the heat transfer property of the elastic layer of the pressure roller is positively improved to reduce the temperature rise of the non-sheet passing portion, that is, the difference in the height difference in the longitudinal direction of the pressure roller. Can be obtained.

  In Patent Document 1, Patent Document 2, and Patent Document 3, high thermal conductive fillers such as alumina, zinc oxide, and silicon carbide are used as a base rubber in order to improve the thermal conductivity of the elastic layer of the fixing roller and the pressure roller. The addition is disclosed.

  Patent Document 4 discloses a method in which carbon fiber is contained in the elastic layer in order to improve the heat conduction of the rotating body (fixing belt) having the elastic layer.

  Patent Document 5 discloses an invention in which an anisotropic filler such as graphite is contained in an elastomer layer to improve the thermal conductivity in the roller thickness direction.

Patent Document 6 discloses an invention in which a fabric layer using pitch-based carbon fibers is provided in an elastic layer of a pressure roller. This pressure roller has a high heat conductive layer with excellent heat conductivity and an elastic layer. However, since it is a woven fabric or a configuration similar to it, the high thermal conductive rubber composite layer has high hardness. Therefore, when reducing the hardness of the entire pressure roller, a measure is taken to use foamed sponge rubber for the lower elastic layer. However, since the elastic layer is made of foamed sponge, the pressure roller does not have much durability. Therefore, the pressure roller is used as a pressure member of a fixing device mounted on a low-speed image forming apparatus. It was preferable.
JP-A-11-116806 Japanese Patent Laid-Open No. 11-158377 JP 2003-208052 A JP 2002-268423 A JP 2000-39789 A JP 2002-351243 A

  Even if fillers such as alumina, zinc oxide, silicon carbide, carbon fiber, and graphite as described in Patent Document 1 to Patent Document 5 are added to the elastic layer to increase thermal conductivity, a small amount is added. In this case, the desired thermal conductivity cannot be obtained. On the other hand, when the hardness of the base rubber forming the elastic layer is lowered in order to reduce the hardness of the pressure roller while adding a large amount of the above filler, the durability performance as rubber may be insufficient. is there.

  During a so-called cold start in which the printer starts printing from a state in which the fixing device is sufficiently cooled, the temperature of the pressure roller surface is too low, so that water vapor is generated when the recording material passes through the nip portion. Then, the water vapor may be condensed on the surface of the pressure roller, and the conveyance of the recording material may become unstable.

  Accordingly, an object of the present invention is a pressurizing member that forms a nip portion for heating while nipping and conveying a recording material in contact with a heating member, and can reduce overheating in an area where the recording material does not pass. Another object of the present invention is to provide a pressurizing member capable of improving durability and recording material transportability.

  Moreover, the objective of this invention is providing the image heating apparatus which has said pressurizing member.

  Another object of the present invention is to provide an image forming apparatus having the above-described image heating apparatus.

  (1) A configuration for achieving the above object is a pressurizing member that forms a nip portion that is in contact with a heating member and heats the recording material while nipping and conveying the recording material, and includes a release layer and an elastic layer. In the pressurizing member having a filler having thermal conductivity anisotropy in the filler, the filler is bound by an adhesive that bonds the release layer and the elastic layer.

  (2) Further, a configuration for achieving the above object includes a heating member and a pressure member that forms a nip portion in contact with the heating member, and sandwiches and conveys the recording material at the nip portion. However, an image heating apparatus that heats an image carried on a recording material has the pressure member described in (1) as the pressure member.

  (3) In addition, the configuration for achieving the above object includes an image carrier, transfer means for transferring and carrying an unfixed image carried by the image carrier onto a recording material, and undetermined by the recording material. An image forming apparatus having fixing means for fixing a received image to a recording material, characterized in that the image heating apparatus described in (2) is provided as the fixing means.

  According to the present invention, there is provided a pressure member that forms a nip portion that is in contact with the heating member to heat the recording material while nipping and conveying the recording material, and alleviates an excessive temperature rise in a region where the recording material does not pass through the nip portion. In addition, it is possible to provide a pressure member capable of improving durability and recording material conveyance.

  In addition, according to the present invention, an image heating apparatus having the above pressure member can be provided.

  In addition, according to the present invention, an image forming apparatus having the above-described image heating apparatus can be provided.

  The present invention will be described with reference to the drawings.

[Example 1]
(1) Example of Image Forming Apparatus FIG. 1 is a schematic configuration model diagram showing an example of an image forming apparatus in which the image heating apparatus according to the present invention can be mounted as a heat fixing apparatus (fixing means). This image forming apparatus is an electrophotographic laser beam printer.

  The printer shown in this embodiment has a rotating drum type electrophotographic photosensitive member (hereinafter referred to as a photosensitive drum) 1 as an image carrier. The photosensitive drum 1 has a configuration in which a photosensitive material layer such as OPC, amorphous Se, or amorphous Si is formed on the outer peripheral surface of a cylinder (drum) -like conductive substrate such as aluminum or nickel.

  The photosensitive drum 1 is rotationally driven in the clockwise direction indicated by an arrow a at a predetermined peripheral speed (process speed). In the rotation process, the outer peripheral surface (surface) of the photosensitive drum 1 has a predetermined polarity by a charging roller 2 as a charging unit.・ Evenly charged to the potential. Scanning exposure is performed on the uniformly charged surface of the photosensitive drum 1 with a laser beam LB output from the laser beam scanner 3 and subjected to modulation control (ON / OFF control) according to image information. As a result, an electrostatic latent image corresponding to the target image information is formed on the surface of the photosensitive drum 1.

  The latent image is developed and visualized as an unfixed toner image (unfixed image) by using the toner T by the developing device 4 as developing means. As a development method, a jumping development method, a two-component development method, a FEED development method, or the like is used, and is often used in combination with image exposure and reversal development.

  On the other hand, the recording material P stacked and stored in the feeding cassette 9 is driven one by one by driving the feeding roller 8 and conveyed to the registration roller 11 through a sheet path having the guide 10 and the registration roller 11. The registration roller 11 feeds the recording material P to the transfer nip T between the surface of the photosensitive drum 1 and the outer peripheral surface (surface) of the transfer roller 5 at a predetermined control timing. The recording material P is nipped and conveyed by the transfer nip T, and the toner image on the surface of the photosensitive drum 1 is sequentially transferred onto the surface of the recording material P by a transfer bias applied to the transfer roller 5 in the conveyance process. As a result, the recording material P carries an unfixed toner image.

  The recording material P carrying an unfixed toner image (unfixed image) is sequentially separated from the surface of the photosensitive drum 1, discharged from the transfer nip T, and introduced into the nip N of the heat fixing device 6 through the conveyance guide 12. . When the recording material P receives heat and pressure from the nip portion N of the fixing device 6, the toner image is fixed on the surface of the recording material P by heating and fixing.

  The recording material P that has exited the fixing device 6 passes through a sheet path having a conveyance roller 13, a guide 14, and a discharge roller 15, and is printed out on a discharge tray 16.

  Further, the surface of the photosensitive drum 1 after separation of the recording material is cleaned by a cleaning device 7 as a cleaning means to remove adhered contaminants such as transfer residual toner, and is repeatedly used for image formation.

  The printer of this embodiment is a printer that supports A3 size paper, and has a printing speed of 50 sheets / minute (A4 landscape). Further, as the toner, a toner having a glass transition point of 55 to 65 ° C. containing styrene acrylic resin as a main material and internally adding or externally adding a charge control agent, a magnetic material, silica or the like as necessary.

(2) Fixing device 6
In the following description, regarding the fixing device and the members constituting the fixing device, the longitudinal direction is a direction orthogonal to the recording material conveyance direction on the surface of the recording material. The short side direction is a direction parallel to the recording material conveyance direction on the surface of the recording material. The width is a dimension in the short direction.

  FIG. 2 is a schematic configuration model diagram of the fixing device 6. The fixing device 6 is a film heating type fixing device.

  Reference numeral 21 denotes a laterally long film guide member (stay) having a substantially semicircular arc shape and a saddle shape in cross section and having a longitudinal direction as a longitudinal direction in the drawing. Reference numeral 22 denotes a horizontally long heating element (heater) accommodated and held in a groove formed along the longitudinal direction at the approximate center of the lower surface of the film guide member 21. Reference numeral 23 denotes a flexible member as a heating member. The flexible member 23 is an endless belt-shaped (cylindrical) heat-resistant film (flexible sleeve) that is loosely fitted around the film guide member 21 with a heating element.

  Reference numeral 24 denotes a horizontally long elastic pressure roller as a pressure member that is pressed against the lower surface of the heating body 22 with the film 23 interposed therebetween. N is a nip portion (fixing nip portion) formed between the heating body 22 by elastic deformation of the elastic layer 24a of the pressure roller 24 and the high thermal conductive elastic layer 24b which are in contact with the heating body 22 with the film 23 interposed therebetween. It is. The pressure roller 24 is driven to rotate in the counterclockwise direction indicated by an arrow b at a predetermined peripheral speed when the driving force of the driving source M is transmitted through a power transmission mechanism such as a gear (not shown).

  The film guide member 21 is, for example, a molded product of a heat resistant resin such as PPS (polyphenylene sulfite) or a liquid crystal polymer.

  The heating element 22 is a ceramic heater having a low heat capacity as a whole. The heater 22 shown in this embodiment includes a horizontally long and thin heater substrate 22a such as alumina, and a linear or narrow strip Ag / Pd formed on the surface side (film sliding surface side) along the length. Current heating element (resistance heating element) 22b. The heater 22 has a thin surface protective layer 22c such as a glass layer that covers and protects the energization heating element 22b. A temperature measuring element 25 such as a thermistor is provided on the back side of the heater substrate 22a. The heater 22 is controlled to maintain a predetermined fixing temperature (target temperature) by a power control system (not shown) including a temperature detecting element 25 after the temperature is rapidly raised by supplying power to the energization heating element 22b.

  The film 23 is a single layer film having a total thickness of 100 μm or less, preferably 60 μm or less and 20 μm or more, or a release layer on the surface of the base film in order to reduce the heat capacity and improve the quick start property of the apparatus. It is a coated composite layer film. As a material for the single layer film, PTFE (polytetrafluoroethylene), PFA (tetrafluoroethylene-perfluoroalkyl vinyl ether), PPS, etc. having heat resistance, releasability, strength, durability and the like are used. As a material for the base film, polyimide, polyamideimide, PEEK (polyetheretherketone), PES (polyethersulfone), or the like is used. As a material for the release layer, PTFE / PFA / FEP (tetrafluoroethylene-perfluoroalkyl vinyl ether) or the like is used.

  The pressure roller 24 includes a cored bar 24d made of iron or aluminum, an elastic layer 24a obtained by a material described in detail in the next section (3), a manufacturing method, a high thermal conductive adhesive layer 24b, a mold release The layer 24c and the like are included. The surface of the pressure roller 24 is pressed with a predetermined pressure by a predetermined pressure mechanism (not shown) on the surface protective layer 22 c of the heating body 22 through the film 23. In response to the applied pressure, the elastic layer 24a of the pressure roller 24 is elastically deformed, and a nip portion N having a predetermined width necessary for heating and fixing an unfixed toner image is formed between the surface of the pressure roller 24 and the surface of the film 23. Is done.

  The film 23 is driven by the rotation of the pressure roller 24 at least when the pressure roller 24 is driven to rotate counterclockwise as indicated by the arrow b at the time of image formation. That is, when the pressure roller 24 is rotationally driven, a rotational force is applied to the film 23 by the frictional force between the outer peripheral surface (surface) of the pressure roller 24 and the outer peripheral surface (surface) of the film 23 in the nip portion N. When the film 23 is rotating, the inner peripheral surface (inner surface) of the film 23 contacts and slides on the surface protective layer 22 c of the heater 22 at the nip portion N. In this case, in order to reduce the sliding resistance between the inner surface of the film 23 and the surface protective layer 22c of the heater 22, a lubricant such as heat resistant grease may be interposed therebetween.

  Thus, in the state where the film 23 is rotated by the rotational drive of the pressure roller 24 and the heater 22 rises to a predetermined fixing temperature and the temperature is adjusted, the recording material P carrying the unfixed toner image t is transferred to the nip portion. N. The recording material P is nipped and conveyed at the nip portion N by the surface of the film 23 and the surface of the pressure roller 24. In the conveying process, the heat of the heater 22 is applied to the toner image t through the film 23 and the nip pressure of the nip portion N is applied. As a result, the toner image t is heated and fixed on the surface of the recording material P. The recording material P exiting the nip portion N is separated from the surface of the film 23 and conveyed, and is discharged from the fixing device 6.

  Since the film heating type fixing device 6 as in this embodiment uses the heater 22 having a small heat capacity and a high temperature rise, the time required for the heater 22 to reach a predetermined fixing temperature can be greatly shortened. Therefore, it can be easily raised to a high fixing temperature even from room temperature. Therefore, it is not necessary to adjust the standby temperature when the fixing device 6 is in a standby state during non-printing, and power can be saved.

  Further, a flange that only receives the end portion of the film 23 as a film displacement movement restricting means because the tension is not substantially applied to the rotating film 23 other than the nip portion N and the fixing device 6 is simplified. Only members (not shown) are provided.

(3) Pressure roller 24
About the said pressure roller 24, the material, the molding method, etc. which comprise it are demonstrated in detail below.

3-1) Layer Configuration of Pressure Roller 24 FIG. 3 is a layer configuration model diagram of the pressure roller 24.

  The pressure roller 24 shown in this embodiment has an elastic layer (heat-resistant rubber layer) 24a on the outer periphery of a round shaft metal core 24d, and a high heat conductive adhesive layer 24b as an adhesive layer on the outer periphery of the elastic layer 24a. . Further, a release layer 24c is provided on the outer periphery of the high thermal conductive adhesive layer 24b.

3-1-1) Elastic layer 24a
The thickness of the entire elastic layer 24a used for the pressure roller 24 is not particularly limited as long as it can form the nip portion N having a desired width, but is preferably 2 to 10 mm. As a material of the elastic layer 24a, general heat-resistant solid rubber such as silicone rubber, foamed sponge rubber, or the like can be used. Both materials have sufficient heat resistance and durability when used in the fixing device 6 and have favorable elasticity (softness). Therefore, general heat resistant solid rubber such as silicone rubber or foamed sponge rubber is suitable as the main material of the elastic layer 24a. Here, the thickness refers to the radial dimension of the pressure roller 24.

  A method for forming the elastic layer 24a is not particularly limited, but general mold molding can be suitably used.

3-1-2) High thermal conductive adhesive layer 24b
The high thermal conductive adhesive layer 24b is formed between the elastic layer 24a and the release layer 24c. The high thermal conductive adhesive layer 24b is required to contain the high thermal conductive needle-like filler 24f, which is a needle-like filler, as a filler having thermal conductivity anisotropy in the major and minor axes of the filler in the adhesive 24e. (See FIGS. 6A and 6B). That is, a filler having thermal conductivity anisotropy is used in the filler. Here, the heat conduction anisotropy means that, for example, the needle-like filler has high heat conduction only in the long axis direction and low heat conduction in the short axis direction. The adhesive 24e is for bonding the release layer 24c and the elastic layer 24a. The filler 24f is bound between the release layer 24c and the elastic layer 24a by the adhesive 24e.

  As the adhesive 24e, an addition-curable silicone rubber adhesive or the like can be used.

  Specifically, the addition-curable silicone rubber adhesive contains an organopolysiloxane having an unsaturated hydrocarbon group represented by a vinyl group, a hydrogenorganopolysiloxane, and a platinum compound as a crosslinking catalyst. The organopolysiloxane, hydrogen organopolysiloxane, and platinum compound are cured by an addition reaction. As such an adhesive, a known adhesive can be used.

  Examples of self-adhesive components include:

-At least one selected from the group consisting of alkenyl groups such as vinyl groups, (meth) acryloxy groups, hydrosilyl groups (SiH groups), epoxy groups, alkoxysilyl groups, carbonyl groups, and phenyl groups, preferably two or more types A silane having a functional group of
An organosilicon compound such as a cyclic or linear siloxane having 2 to 30 silicon atoms, preferably 4 to 20 silicon atoms,
-Containing at least one functional group that can contribute to hydrosilylation addition reaction, and contains 1 to 4 aromatic rings such as phenylene structure having 1 to 4 valences in one molecule. A non-silicon-based organic compound that may contain an oxygen atom in the molecule. Here, with respect to the above aromatic ring having a monovalent to tetravalent phenylene structure, an aromatic ring having a bivalent to tetravalent phenylene structure is preferred. Moreover, it is preferable that 1 or more and 2 or less aromatic rings, such as a phenylene structure, are contained in 1 molecule about said aromatic rings, such as a phenylene structure, contained in 1 molecule or more and 4 or less. Examples of functional groups that can contribute to the hydrosilylation addition reaction include alkenyl groups and (meth) acryloxy groups. Moreover, it is preferable to contain 2 or more and 4 or less functional groups that can contribute to the hydrosilylation addition reaction. In the above non-silicon-based organic compound, the non-silicon-based refers to a system that does not contain a silicon atom in the molecule.

  The above self-adhesive components can be used singly or in combination of two or more.

  Such addition-curable silicone rubber adhesives are also commercially available and can be easily obtained.

  As the filler 24f, an elongated fiber-shaped (needle-shaped) filler having a length substantially the same as the entire length of the pressure roller 24, or a fiber-shaped (needle-shaped) filler relatively shorter than the filler can be used.

  When a filler 24f having a length substantially the same as the entire length of the pressure roller 24 is used, it is difficult to knead the filler 24f with a liquid adhesive before curing. Therefore, when the adhesive layer 24b is formed, the filler 24f is arranged so that the fiber axis direction of the filler 24f is in the longitudinal direction of the adhesive layer 24b, and the filler 24f is sandwiched between the liquid adhesive in the adhesive layer 24b. Is preferred. By disposing the filler 24f in the longitudinal direction of the adhesive layer 24b in the adhesive layer 24b, the thermal conductivity in the longitudinal direction of the adhesive layer 24b can be enhanced.

  On the other hand, since the relatively short filler 24f has an elongated fiber shape, when kneaded with the liquid adhesive before curing, when the adhesive layer 24b is molded, the flow direction of the liquid adhesive before curing, that is, the adhesive layer 24b. It is easy to orient in the longitudinal direction. Therefore, after the adhesive layer 24b is cured, the filler 24f can increase the thermal conductivity in the longitudinal direction of the adhesive layer 24b.

  The thickness of the adhesive layer 24b is preferably 0.1 to 0.5 mm in terms of performance and molding. The thickness of the adhesive layer 24b is not limited to 0.1 to 0.5 mm and can be appropriately adjusted. For example, in order to increase the thickness of the adhesive layer 24b, a liquid adhesive kneaded with the filler 24f can be applied twice at the time of forming the adhesive layer 24b.

  Here, in the adhesive layer 24b as the heat conductive adhesive layer, the filler 24f, which is a filler having thermal conductivity anisotropy, is contained in an amount of 30 Vol% or more by volume with respect to the adhesive 24e. The volume fraction of the thermally conductive anisotropic filler is determined by the formula of (volume of all fillers contained in the adhesive) / (volume of adhesive + volume of all fillers) × 100 Vol%. The thermal conductivity of the filler 24f in the longitudinal direction orthogonal to the recording material conveyance direction is 100 W / (m · K) or more (measurement method: laser flash method). The thermal conductivity of the adhesive layer 24b in the longitudinal direction perpendicular to the recording material conveyance direction is 2.0 W / (m · K) or more. As a method for measuring the thermal conductivity of the adhesive layer 24b, the thermal conductivity of only the adhesive layer 24b is obtained using a hot disk method thermal property measuring device. Further, the average length of the filler 24f is 100 μm or more. For the average length of the filler 24f, the average length of the filler 24f is obtained by optical observation.

  Next, how the filler 24f is oriented in the adhesive layer 24b will be described in detail.

  4A is an overall perspective view of an elastic layer formed product obtained by molding an elastic layer 24b on the outer periphery of the elastic layer 24a on the cored bar 24d, and FIG. 4B is a right side view of the elastic layer formed product of FIG. is there. FIG. 5 is an enlarged perspective view of a cut-out sample 24b1 of the adhesive layer 24b of the elastic layer forming product of FIG. 6A is an enlarged view of a section a of the cutout sample 24b1 in FIG. 5, and FIG. 6B is an enlarged view of a section b of the cutout sample 24b1 in FIG. FIG. 7 is an explanatory view showing the fiber diameter portion D and the fiber length portion L of the filler 24f.

  As shown in FIG. 4 (a), in the elastic layer formed product in which the adhesive layer 24b is molded on the outer periphery of the elastic layer 24a on the metal core 24d, the adhesive layer 24b is arranged in the x direction (circumferential direction) and the y direction (longitudinal direction). ) And cut out. Then, in the cut sample of the adhesive layer 24b, the a cross section in the x direction and the b cross section in the y direction are observed as shown in FIG. Then, in the cross section a in the x direction, the fiber diameter portion D (see FIG. 7) of the filler 24f is mainly observed as shown in FIG. 6A, whereas in the b cross section in the y direction, the fiber length portion of the filler 24f is observed. Many Ls (see FIG. 7) are observed.

3-1-3) Release layer 24c
The release layer 24c is formed by covering the adhesive layer 24b with a PFA tube or the like. The thickness of the release layer 24c is not particularly limited as long as it can provide sufficient release properties to the pressure roller 24, but is preferably 20 to 100 μm.

3-2) Embodiment of Pressure Roller 24 FIG. 8 is an explanatory diagram illustrating a molding procedure of the pressure roller 24 according to the first embodiment. FIG. 9 is an explanatory diagram illustrating a molding procedure of the pressure roller 24 according to the second embodiment. FIG. 10 is an explanatory diagram illustrating a molding procedure of the pressure roller 24 according to the third embodiment. 8 to 10, the thickness of each layer is emphasized so that the layer configuration of each pressure roller 24 can be easily understood.

  First, the filler 24f used for each pressure roller 24 according to Example 1, Example 2, and Example 3 is shown. The following two types of pitch-based carbon fibers are used as the filler 24f.

  90-60S: pitch-based carbon fiber, trade name: XNG-90-60S, manufactured by Nippon Graphite Fiber Co., Ltd., average fiber diameter: 10 μm, average fiber length L: 320 mm, thermal conductivity 500 W / (m · K) .

  100-15M: pitch-based carbon fiber, trade name: XN-100-15M, manufactured by Nippon Graphite Fiber Co., Ltd., average fiber diameter: 9 μm, average fiber length L: 150 μm, thermal conductivity 900 W / (m · K) .

[Example 1]
In FIG. 8, first, an elastic layer 24a having a thickness of 3.5 mm is formed on the outer periphery of an aluminum core bar 24d having a thickness of 3.5 mm by a molding method using addition reaction curing type silicone rubber having a density of 1.20 g / cm ^3. An elastic layer formation having a diameter of 29 is obtained (see (a)). Here, as the temperature condition, heat curing was performed at 150 ° C. × 30 minutes.

  Next, a method for forming the adhesive layer 24b will be described.

  Addition-curing silicone rubber adhesive, trade name: SE1819CV A & B, Toray Dow Corning A and B liquids are mixed in a ratio of 1: 1 to obtain an adhesive 24e stock solution.

  This adhesive stock solution is applied to the outer periphery of the elastic layer 24a of the elastic layer formation so as to have a uniform thickness. Then, a plurality of pitch-based carbon fibers 90-60S as fillers 24f are arranged in the applied adhesive 24e stock solution in the circumferential direction of the elastic layer formation so that the fiber axis direction is the longitudinal direction of the elastic layer formation (( b)). Next, cover the pitch-based carbon fiber 90-60S with a fluororesin sheet in which the adhesive 24e stock solution has been thinly and uniformly applied so as not to peel off from the elastic layer formation, and heat cure at 150 ° C. for 30 minutes. It was. After the heat curing, the fluororesin sheet is peeled off.

  Thereafter, the stock solution of adhesive 24e was further applied to the outer periphery of the elastic layer formation from above the pitch-based carbon fiber 90-60S. Then, a PFA tube (thickness: 50 μm) is coated as a release layer 24c on the outer periphery of the elastic layer formed product coated with the adhesive 24e stock solution, and heated and cured at 200 ° C. for 10 minutes, and a longitudinal length of 320 mm is added. A pressure roller 24 was obtained (see (c)). Here, PFA is a tetrafluoroethylene / perfluoroalkyl vinyl ether copolymer. The thickness of the adhesive layer 24b is 0.5 mm.

[Example 2]
In FIG. 9, first, in the same manner as in Example 1, an elastic layer formed product having an elastic layer thickness of 3.75 mm and φ29.5 is obtained (see (a)).

  Next, a method for forming the high thermal conductive adhesive layer 24b will be described.

  To the same adhesive 24e stock solution as in Example 1, pitch-based carbon fiber 100-15M as filler 24f was uniformly blended and kneaded so as to have a volume ratio of 35% to obtain an adhesive composition. This adhesive composition was applied to the outer periphery of the elastic layer 24a of the elastic layer forming product so as to have a uniform thickness (see (b) and the enlarged detail of part A).

  Further, a PFA tube (thickness 50 μm) is coated as a release layer 24c on the outer periphery of the elastic layer formed product coated with the adhesive composition in the longitudinal direction of the elastic layer formed product, and is heated and cured at 200 ° C. for 10 minutes. A pressure roller 24 having a length of 320 mm in the longitudinal direction was obtained (see (c)). The thickness of the adhesive layer 24b is 0.25 mm.

  In Example 2, pitch-based carbon fiber 100-15M was blended with the adhesive 24e stock solution at a volume ratio of 35%. However, the adhesive 24e stock solution is not limited to this, and other adhesive stock solutions may be used. Other adhesive stock solutions include addition-curing silicone rubber adhesive, trade name: SE1816CV, manufactured by Toray Dow Corning, trade name: TSE3033, manufactured by Momentive Performance Materials Japan GK. This adhesive stock solution can be used according to the blending amount of pitch-based carbon fiber 100-15M. The adhesive stock solution can be appropriately diluted and used using a trade name: SE1700 diluent, manufactured by Toray Dow Corning Co., Ltd., and the blending amount can be increased to about 60%.

[Example 3]
In FIG. 10, first, the same elastic layer forming product as in Example 1 is obtained (see (a)).

  Next, a method for forming the high thermal conductive adhesive layer 24b will be described.

  The same adhesive composition as in Example 2 is applied to the outer periphery of the elastic layer 24a of the elastic layer formation so that the thickness is uniform (see (b)). The applied adhesive composition is denoted by reference numeral 24b-1. At this time, by applying the adhesive composition 24b-1 in the longitudinal direction of the elastic layer 24a, the pitch-based carbon fibers 100-15M are easily oriented in the longitudinal direction. Here, it was cured by heating at 150 ° C. for 30 minutes.

  Further, in order to increase the thickness of the adhesive layer 24b, the adhesive composition is applied again. The adhesive composition applied the second time is designated as 24b-2 (see (c)). That is, the heat conductive adhesive layer is formed by being applied to the elastic layer a plurality of times. A PFA tube (thickness 50 μm) is coated in the longitudinal direction of the elastic layer formation on the outer periphery of the elastic layer formation to which the adhesive composition 24b-2 is applied, and is heated and cured at 200 ° C. for 10 minutes. A pressure roller 24 having a length of 320 mm in the direction was obtained (see (d)). The thickness of the adhesive layer 24b is 0.5 mm.

3-3) Evaluation of Pressure Roller 24 As a comparative example to be compared with each pressure roller 24 in order to evaluate the performance of each pressure roller 24 according to Example 1, Example 2, and Example 3 described above. The following pressure roller 24 was produced.

  FIG. 11 is an explanatory diagram showing the layer structure of the pressure roller 24 according to the comparative example. In FIG. 11, the layer thickness is emphasized so that the layer configuration of the pressure roller 24 can be easily understood.

[Comparative example]
In FIG. 11, silicone rubber having a thermal conductivity of 0.4 W / (m · k) was formed as an elastic layer 24a on the outer periphery of an aluminum cored bar 24d having a thickness of 4 mm. The silicone rubber used in this comparative example is set to have a higher thermal conductivity by adding a little more filler than that having a general thermal conductivity of 0.2 W / (m · k) or less. . Silica, which is also used as a reinforcing agent, was used as the filler. The pressure roller 24 according to this comparative example has the same length and outer shape as the pressure roller 24 of Example 1, except that the adhesive layer 24b is not provided.

[Performance evaluation]
<Non-paper-passing area temperature rise>
For performance evaluation, four film heating type fixing devices each having the pressure roller 24 according to Example 1, Example 2, Example 3, and Comparative Example manufactured by the above method were mounted on a printer having the same configuration. . In each printer, the peripheral speed (process speed) of the pressure roller 24 of the fixing device is adjusted to 234 mm / sec, the fixing temperature is set to 220 ° C., and the temperature of the non-sheet passing area at that time is measured. did. That is, the paper that is passed (introduced) as the recording material P to the nip portion N of the fixing device is LTR horizontal size paper (75 g / m ² ). The temperature of the surface of the film 23 in the paper passing area (the area where the LTR horizontal size paper does not pass) was measured.

<Durability>
With the fixing temperature set at 220 °, 150,000 sheets of LTR horizontal size paper (75 g / mm ² ) were passed at 50 sheets / minute to overheat the non-passing area. The rubber state was evaluated.

<Transportability>
LTR horizontal size paper (75 g / mm ² ) that has been sufficiently left in a high-temperature and high-humidity environment (32 ° C./80%) to print from a state in which the fixing device is sufficiently cooled, fixing from a so-called cold start The transportability was evaluated when 20 sheets were continuously passed at a temperature of 220 °. Here, the state in which the fixing device is sufficiently cooled is a room temperature (about 25 ° C.) state.

<Result of evaluation>
In the fixing device including the pressure roller 24 according to the comparative example, sufficient fixing ability can be secured without causing trouble in the nip formation necessary for heating and fixing an unfixed toner image, and durability and transportability are also good. It was. However, since the temperature rise in the non-sheet passing region is as high as 310 ° C., problems such as damage to each part in the fixing device occur.

  In the fixing device including the pressure roller 24 according to the first embodiment, the carbon fiber 24f having a longer fiber length than the carbon fiber 24f in the adhesive layer 24b of the pressure roller 24 according to the second embodiment is used. 24b. Accordingly, since the thermal conductivity in the longitudinal direction of the adhesive layer 24b is 10.7 W / (m · K) and the non-sheet passing region temperature is 272 ° C., a sufficient temperature rise suppressing effect is obtained in the non-sheet passing region. It was seen. At this time, the temperature of the surface of the film 23 in the sheet passing area (area through which LTR horizontal size paper passes) was 205 ° C. Since the temperature of the surface of the film 23 in the sheet passing area is the same in all the fixing devices incorporating the pressure rollers 24 of the first embodiment, the second embodiment, and the third embodiment, the description thereof will be omitted.

  On the other hand, sufficient fixability can be secured without hindering the nip formation necessary for heat fixing of an unfixed toner image. Also, durability and transportability were good.

  In the fixing device including the pressure roller 24 according to the second embodiment, the carbon fiber 24f having a relatively shorter fiber length than the carbon fiber 24f in the adhesive layer 24b of the pressure roller 24 according to the first embodiment is used. It is contained in the adhesive layer 24b. Accordingly, since the thermal conductivity in the longitudinal direction of the adhesive layer 24b is 9.8 W / (m · K) and the non-sheet passing region temperature is 271 ° C., the temperature rise suppressing effect is seen in the non-sheet passing region. .

  On the other hand, sufficient fixability can be secured without hindering the nip formation necessary for heat fixing of an unfixed toner image. Also, durability and transportability were good.

  In the fixing device including the pressure roller 24 according to the third embodiment, the carbon fiber 24f having a relatively short fiber length than the carbon fiber 24f in the adhesive layer 24b of the pressure roller 24 according to the first embodiment is used. It is contained in the adhesive layer 24b. Further, the thickness of the adhesive layer 24b is increased. Therefore, since the thermal conductivity in the longitudinal direction of the adhesive layer 24b is 19.6 W / (m · K) and the non-sheet passing region temperature is 267 ° C., the temperature rise suppressing effect is seen in the non-sheet passing region. .

  On the other hand, sufficient fixability can be secured without hindering the nip formation necessary for heat fixing of an unfixed toner image. Also, durability and transportability were good.

  As described above, by using the filler 24f having thermal conductivity and making the thermal conductivity λy in the longitudinal direction of the adhesive layer 24b higher than the thermal conductivity in the recording material conveyance direction, an effect of suppressing the temperature rise was observed. . In addition, while achieving λy ≧ 2.0 W / (m · K), sufficient fixability can be secured at the same time without hindering the nip formation as the pressure roller 24. Therefore, by using the pressure rollers 24 of the first, second, and third embodiments for the fixing device 6, it is possible to alleviate the excessive temperature rise in the area where the recording material P does not pass in the nip portion N. Further, it is possible to improve the durability performance of the pressure roller 24 and the transportability of the recording material P.

(4) Others 4-1) In the heating and fixing apparatus 6 of the film heating system in the above embodiment, the heating body 22 is not limited to a ceramic heater. For example, a contact heating body using a nichrome wire or the like, or an electromagnetic induction exothermic member such as an iron plate piece may be used. The heating element 22 does not necessarily have to be located in the fixing nip portion (pressure nip portion).

  An electromagnetic induction heating type heat fixing device in which the film 23 itself is an electromagnetic induction heat-generating metal film can also be used.

  The film 23 may be constructed as a device configuration in which the film 23 is stretched between a plurality of suspension members and rotated by a drive roller. Moreover, the film 23 can also be made into the apparatus structure which makes it run to the winding axis | shaft side by making it into the end | end long member roll-rolled around the delivery axis | shaft.

  4-2) The heat fixing device is not limited to the film heating method, and may be a heat roller method.

  4-3) The heat-fixing device is not limited to the heat-fixing device of the embodiment, but also an image heating device that presupposes an unfixed image and a surface property such as gloss by reheating the recording medium carrying the image. It may be an image heating device.

Schematic model diagram of an example of an image forming apparatus Schematic model diagram of fixing device Model diagram of layer structure of pressure roller (A) is the whole perspective view of the elastic layer formation which shape | molded the elastic layer on the outer periphery of the elastic layer on a metal core, (b) is a right view of the elastic layer formation of (a) FIG. 4A is an enlarged perspective view of a cut-out sample of the adhesive layer of the elastic layer formation product in FIG. (A) is an enlarged view of the a section of the cutout sample of FIG. 5, (b) is an enlarged view of the b section of the cutout sample of FIG. Explanatory drawing showing the fiber diameter part and fiber length part of a high thermal conductive needle filler Explanatory drawing showing the molding procedure of the pressure roller concerning Example 1 Explanatory drawing showing the molding procedure of the pressure roller concerning Example 2 Explanatory drawing showing the molding procedure of the pressure roller concerning Example 3 Explanatory drawing showing the layer constitution of the pressure roller according to the comparative example

Explanation of symbols

23. Heat-resistant film, 24 Pressure roller, 24a Elastic layer, 24b Adhesive layer, 24c Release layer, 24e Adhesive, 24f High heat conductive needle filler, P Recording material, N Nip , T ... Unfixed toner image (unfixed image)

Claims (12)

A pressurizing member that forms a nip for heating while nipping and conveying a recording material in contact with a heating member, and having a thermal conductivity anisotropy in a filler between a release layer and an elastic layer In a pressure member comprising:
The pressure member, wherein the filler is bound by an adhesive that bonds the release layer and the elastic layer.   The pressure member according to claim 1, further comprising an adhesive layer containing the filler and the adhesive between the release layer and the elastic layer.   The pressure member according to claim 2, wherein the adhesive layer contains the filler in a volume ratio of 30 Vol% or more with respect to the adhesive.   The pressure member according to claim 2, wherein the filler is provided between the release layer and the elastic layer by applying the adhesive of the adhesive layer to the elastic layer. .   The pressure member according to claim 2, wherein the filler is provided between the release layer and the elastic layer by applying the adhesive layer to the elastic layer.   The pressure member according to claim 2, wherein the filler is provided between the release layer and the elastic layer by applying the adhesive layer to the elastic layer a plurality of times.   The pressure member according to any one of claims 1 to 6, wherein a thermal conductivity of the filler in a longitudinal direction orthogonal to a recording material conveyance direction is 100 W / (m · K) or more.   The pressurization according to any one of claims 2 to 6, wherein the thermal conductivity of the adhesive layer in the longitudinal direction perpendicular to the recording material conveyance direction is 2.0 W / (m · K) or more. Element.   The pressure member according to any one of claims 1 to 8, wherein the filler having thermal conductivity anisotropy is a needle-like filler.   The pressure member according to claim 9, wherein an average length of the needle-like filler is 100 μm or more. An image heating apparatus comprising: a heating member; and a pressure member that forms a nip portion in contact with the heating member, and heats an image carried by the recording material while nipping and conveying the recording material at the nip portion In
An image heating apparatus comprising the pressure member according to claim 1 as the pressure member. Image formation comprising: an image carrier; transfer means for transferring and carrying an unfixed image carried by the image carrier on a recording material; and fixing means for fixing an unfixed image carried by the recording material to the recording material In the device
An image forming apparatus comprising the image heating apparatus according to claim 11 as the fixing unit.