JP2005070445A - Pressure roller, heating device and image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To make on-demand performance compatible with low power consumption (energy saving) by making heat capacity as small as possible in an elastic pressure roller B forming a press-contact nip part N with a heating member A and holding and transporting material to be heated P by the nip part. <P>SOLUTION: By setting form where the elastic roller part 32 of the pressure roller B is made an airtight hollow body and gas is enclosed in a hollow 34 so that fixed internal pressure or more may be applied or setting form where a plurality of elastic air-sac bodies in which gas is enclosed are included, the elastic rubber amount of the elastic roller part 32 is made smaller so as to make the heat capacity smaller in the pressure roller B than the conventional pressure roller having a solid texture elastic roller part. The pressure roller B is equipped with the same function as the conventional pressure roller having the solid texture elastic roller part because the hollow elastic roller part has sufficient tensile elasticity by making the internal pressure of the hollow elastic roller part 32 higher, and maintains fixed nip width by fixed pressure force with the heating member A. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention forms a pressure nip portion with a heating member, a pressure roller for nipping and conveying the material to be heated at the pressure nip portion, and nipping and conveying the material to be heated at the pressure nip portion between the heating member and the pressure roller. And an image forming apparatus such as an electrophotographic apparatus and an electrostatic recording apparatus provided with the heating apparatus as an image heating apparatus.

  As a fixing device that heats and fixes an unfixed toner image formed and supported on a recording material by a transfer method or a direct method on a recording material in an image forming apparatus such as a copying machine or a laser beam printer, a heat roller type heating device is widely used. in use. A film heating type heating apparatus is also put into practical use.

  The heating device of the heat roller system includes a heating body (heating element) such as a halogen heater, heated by the heating body and maintained at a predetermined fixing temperature, and the heat roller (fixing roller). An elastic pressure roller that is arranged in parallel with the roller and press-contacts with the heat roller as a basic configuration. The roller pair is rotated, and an image is formed on the fixing nip portion (heating nip portion) that is the mutual press-contact portion of the roller pair. A recording material as a material to be heated on which a non-fixed toner image to be fixed is formed is carried and is nipped and conveyed, and the unfixed toner image is applied to the recording material surface by the heat of the heat roller and the pressure of the fixing nip portion. Fixing by heat and pressure.

  For example, Patent Documents 1 to 4 disclose a film heating type heating apparatus. That is, a heat-resistant film (fixing film) is generally sandwiched between a ceramic heater as a heating element and an elastic pressure roller to form a fixing nip portion (heating nip portion). A recording material that forms and supports an unfixed toner image to be fixed as an image to be heated is introduced between the pressure roller and nipped and transported together with the film. The unfixed toner image is heat-pressed and fixed on the surface of the recording material by the heat from the toner.

This film heating type heating apparatus can constitute an on-demand type heating apparatus by using a ceramic heater and a film having a low heat capacity as compared with a heating roller type heating apparatus.
JP 61-713182 A Japanese Patent Laid-Open No. 2-157878 JP-A-4-44075 JP-A-4-204980

  As described above, the film heating type heating device (fixing device) can constitute an on-demand type heating device in contrast to the heat roller type heating device. It takes a certain amount of time for the to stand up to the fixable state. That is, in order to satisfactorily fix the unfixed toner image on the recording material, an apparatus for starting the power supply to the ceramic heater as the heating body and starting the driving of the pressure roller and the film before passing the paper to the heating device. It is necessary to execute pre-driving (front multi-rotation) to bring the film surface and pressure roller surface to a temperature higher than a certain level necessary for melting the toner. take time. Further, in order to shorten the start-up time and prepare the fixing environment faster, more electric power (power supplied to the ceramic heater) is required.

  In recent years, printing (printing) speed tends to increase, and a speed of 40 sheets (40 ppm) or more per minute is required. In the above-described conventional film heating type heating apparatus, for example, at 14 ppm, the power required to rise to the temperature required for the printer main body to be fixed within 10 seconds is about 600 W, and about 350 W during continuous paper feeding. It was about. At 20 ppm, it was 800 W at the time of start-up and 380 W at the time of paper feed. Similarly, at 40 ppm, it was 900 W at the time of start-up and 400 W at the time of paper feed. As the speed increases further, more power is required.

  On the other hand, to reduce the power at the first start-up, if you start it up over time, it will be in a state where it can print with lower power, but immediately after the user issues a print operation instruction (on-demand printing) The desired output will not be obtained. It is a problem to be solved by the present invention to achieve both on-demand characteristics and low power consumption (energy saving). Further, the basic idea for realizing energy saving of the present invention is to reduce the heat capacity of the heating device component as much as possible. In particular, the conventional pressure roller is basically composed of a shaft member and a solid (solid) elastic roller portion concentrically provided around the shaft member, and the heat capacity of the pressure roller itself is high. The large size is an obstacle to further improvement of the on-demand property of the device. Therefore, the pressure roller has the same function as a pressure roller having a full-fledged elastic roller portion, and has a heat capacity reduced as much as possible. It is a problem to be solved by the present invention to achieve both compatibility and low power consumption (energy saving).

  The present invention is a pressure roller, a heating device, and an image forming apparatus having the following configuration.

  (1) A pressure roller that forms a pressure nip portion with a heating member and sandwiches and conveys a material to be heated at the pressure nip portion, and is provided with a shaft member and an elastic roller that is provided substantially concentrically around the shaft member. A pressure roller, wherein the elastic roller portion is an airtight hollow body, and a gas is sealed in the hollow so as to apply a predetermined internal pressure or more.

  (2) A pressure roller that forms a pressure nip portion with the heating member and sandwiches and conveys the material to be heated at the pressure nip portion, and is provided with a shaft member and an elastic roller provided substantially concentrically around the shaft member. The pressure roller is characterized in that the elastic roller portion is an airtight hollow body and has a valve for sealing gas so that an internal pressure of a certain level or more is applied in the hollow.

  (3) A pressure roller that forms a pressure nip portion with a heating member, and sandwiches and conveys a material to be heated at the pressure nip portion, and includes a shaft member and an elastic roller portion concentrically provided around the shaft member. The pressure roller is characterized in that the elastic roller portion is a hollow body, and a plurality of elastic air sac bodies in which gas is sealed so that an internal pressure of a certain level or more is applied in the hollow.

  (4) The pressure roller according to (1), (2) or (3), wherein the hollow elastic roller portion is composed of a composite of a plurality of materials such as resin and metal.

  (5) In a heating apparatus that includes a heating member and a pressure roller that presses against the heating member to form a heating nip portion, and heats the material to be heated by nipping and heating the heating nip portion, A heating device, wherein the pressure roller is the pressure roller according to any one of (1) to (4).

  (6) The heating device according to (5), wherein the heating member is a heating unit including a roller or a film including a heating body.

  (7) The heating apparatus according to (5) or (6), wherein the heated material is a recording material carrying an unfixed toner image.

  (8) Image forming means for forming and supporting an unfixed toner image on the recording material, and heat fixing means for fixing the unfixed toner image to the recording material. An image forming apparatus, which is the heating apparatus described above.

  That is, the elastic roller part of the pressure roller is made into an airtight hollow body and gas is sealed so that a certain amount of internal pressure is applied in the hollow, or the elastic roller part is made into a hollow body so that the inside of the hollow exceeds a certain value. By adopting a configuration in which a plurality of elastic air sac bodies enclosing gas are encapsulated so that the internal pressure is applied, the amount of elastic rubber in the elastic roller portion is reduced compared to the conventional pressure roller having a solid-walled elastic roller portion. The heat capacity of the pressure roller can be reduced. Moreover, the elastic roller part made into a hollow body encloses a gas in the hollow or encloses a plurality of elastic air sac bodies filled with gas to increase the internal pressure, so that the hollow elastic roller part has sufficient tension elasticity. The function as a pressure roller has the same function as that of a conventional pressure roller having a solid-walled elastic roller portion, and a constant nip width can be maintained by a constant pressure with the heating member.

  According to the present invention, the pressure roller rubber is reduced as much as possible, the heat capacity is reduced, the inside of the pressure roller is made hollow and gas (air) is enclosed to increase the internal pressure, and between the heating member and the pressure roller. By forming the nip with, the power can be reduced by about 15% to 20% compared to the conventional case, and on-demand performance can be achieved.

(1) Example of Image Forming Apparatus FIG. 1 is a schematic configuration model diagram of an example of an image forming apparatus provided with a heating device according to the present invention as an image heating and fixing device. The image forming apparatus of this example is a laser beam printer using a transfer type electrophotographic process.

  Reference numeral 1 denotes a rotating drum type electrophotographic photosensitive member (hereinafter referred to as a photosensitive drum) as an image carrier, which is rotationally driven in a clockwise direction indicated by an arrow a at a predetermined peripheral speed (process speed). 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 uniformly charged to a predetermined polarity and potential by a charging roller 2 as a charging means during the rotation process (in this example, charged to about −600 V). By a laser beam modulated and controlled (ON / OFF control) corresponding to the time-series electric digital pixel signal of the target image information output from the laser beam scanner 3 to the uniformly charged surface of the rotating photosensitive drum 1 By performing scanning exposure L, an electrostatic latent image of target image information is formed on the surface of the rotating photosensitive drum.

  The formed latent image is developed with toner by the developing device 4 and visualized. 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, a transfer material P as a recording material accommodated in the paper feed cassette 9 is fed to one sheet by driving the paper feed roller 8, and passes through a sheet path 12 having a pair of transport rollers 10 and a top sensor 11. 1 and a transfer nip portion Tr that is a pressure contact portion between the transfer roller 5 and a transfer bias (+1 KV to 5 KV in this example) supplied to the transfer roller 5 at a predetermined control timing, The toner image on the surface side of the photosensitive drum 1 is sequentially electrostatically transferred onto the surface.

  The transfer material P that has exited the transfer nip Tr is sequentially separated from the surface of the rotary photosensitive drum 1, guided by the transport unit 6, and introduced into the heating device 7 serving as a heat fixing device, and sandwiched and transported through the fixing nip N. Then, the toner image undergoes a heat fixing process. The heating device 7 will be described in detail in the next section (2).

  The transfer material P exiting the heating device 7 passes through a sheet path 16 having a conveying roller pair 14 and a discharge roller pair 15 and is discharged onto a discharge tray 17.

  Further, the surface of the rotating photosensitive drum after separation of the transfer material is cleaned by the cleaning device 13 to remove adhering contaminants such as transfer residual toner, and is repeatedly used for image formation.

(2) Heating device 7
A heating device 7 as an image heating and fixing device in this embodiment is basically a cylindrical heat-resistant film (fixing film) disclosed in Japanese Patent Application Laid-Open Nos. 4-44075 to 44083, 4-204980 to 204984, and the like. Is a heating device of a film heating method and a pressure roller driving method (tensionless type).

  2 is a front model view of the heating device 7 with the intermediate portion omitted, FIG. 3 is a longitudinal sectional model view with the intermediate portion omitted, and FIG. 4 is a transverse sectional model view. FIG. 5 is an enlarged cross-sectional model view of the fixing nip portion.

  A is a heating unit as a heating member, B is an elastic pressure roller as a pressure rotating member, and a fixing nip portion N is formed by the pressure contact of both A and B.

  The heating unit A includes a cylindrical heat-resistant film (fixing film, hereinafter referred to as a film) 21 as a flexible member, a ceramic heater (hereinafter referred to as a heater) 22 as a heating body, and supports the heater 22 in a heat-insulating manner. The assembly includes a holder 23 made of a heat-resistant material, a pressurizing rigid stay 24 made of a metal such as iron, and an annular flange member 25 serving as a film displacement control means.

  The film 21 has a heat resistance of PTFE, PFA, FEP having a film thickness of 100 μm or less, preferably about 10 to 50 μm, in order to increase heat transfer, reduce heat capacity, and improve quick start properties. Alternatively, a composite layer film in which PTFE, PFA, FEP and the like are mixed and coated on the outer peripheral surface of polyimide, polyamideimide, PEEK, PES, PPS or the like can be used.

The heater 22 is a horizontally long linear heating element having a low heat capacity. On the heater base a (FIG. 5), which is a ceramic base such as alumina (Al ₂ O ₃ ), as the heating resistor b, for example, Ag / Pd (silver) An electric resistance material such as palladium) is applied and fired to a thickness of 10 to 30 μm and a width of 0.8 to 3 mm by screen printing or the like, and glass or fluororesin is coated thereon as an overcoat layer (protective layer) c. It is. The heater 22 is fixedly supported by being fitted in and bonded to a groove 23a (FIG. 5) provided along the length on the outer lower surface of the holder 23. The heater 22 quickly heats up when the energized heat generating resistor b generates heat over the entire length by feeding power to the energized heat generating resistor b, and the temperature rise is detected by the temperature detecting element d, and a control system (not shown). When the image is heated, energization to the heating resistor b is controlled so that the temperature of the temperature detection element d is maintained at a predetermined set temperature.

  The holder 23 is a heat- and heat-insulating member having a substantially semicircular arc-shaped cross section whose longitudinal direction is the direction intersecting the recording material passing direction, and the cylindrical film 21 is against the holder 23 including the heater 22. It fits loosely around the circumference. The holder 23 serves to back up the film 21, pressurize the fixing nip N, support the heater 22, and transport stability when the film 21 rotates.

  The annular flange member 25 is fitted to the end portion side of the holder 23, receives the end portion of the film 21, and restricts the movement movement of the film 21.

  The pressurizing rigid stay 24 is inserted inside the holder 23, and both end portions thereof protrude outward from both end portions of the holder 23.

  The pressure roller B is a hollow type elastic pressure roller according to the present invention, and a metal shaft 31 such as iron or aluminum as a shaft member, and an elastic material such as silicon rubber provided substantially concentrically around the metal shaft 31. The pressure roller is characterized in that the elastic roller portion 32 is an airtight hollow body, and gas is sealed so that an internal pressure of a certain level or more is applied in the hollow portion. The pressure roller B will be described in detail in section (3). The pressure roller B is arranged such that both end portions of the metal shaft 31 are rotatably supported by bearings between a front side and a rear side chassis side plate (not shown) of the apparatus.

  Above the pressure roller B, the above heating unit A is disposed with the lower surface side of the holder 23 facing downward, and both ends of the pressure rigid stay 24 and the spring receiving members 26 and 26 on the apparatus chassis side plate side. A pressing force is applied to the pressurizing rigid stay 24 by contracting the pressurizing springs 27 and 27 therebetween (in this embodiment, a total pressure of 15 kgf). As a result, the lower surface portion of the holder 23 provided with the heater 22 and the pressure roller B are pressed against each other with the film 21 against the elasticity of the elastic roller portion 32 of the pressure roller B, and a fixing nip portion having a predetermined width. N is formed. The heater 22 exists in the fixing nip portion N. The film 21 is backed up by the holder 23 and the heater 22 at the fixing nip N.

  The pressure roller B is rotationally driven in the counterclockwise direction indicated by the arrow in FIG. 4 by the rotational force transmitted to the pressure roller gear G fixed to one end of the metal shaft 31 by the drive source M (FIG. 4). By the rotational driving of the pressure roller B, the rotational force acts on the film 21 by the frictional force between the pressure roller B and the outer surface of the film 21 in the fixing nip portion N. As a result, the film 21 rotates around the holder 23 in the clockwise direction indicated by an arrow while the inner surface of the film 21 slides in close contact with the lower surface of the heater 22 in the fixing nip portion N (pressure roller driving method). The film 21 is in a rotating state having a peripheral speed substantially corresponding to the rotational peripheral speed of the pressure roller B. In order to reduce the mutual sliding frictional force between the lower surface of the heater 22 and the inner surface of the film 21 in the fixing nip portion N, lubrication such as heat-resistant grease is provided between the lower surface of the heater 22 and the inner surface of the film 21 in the fixing nip portion N. The material is interposed.

  Image forming apparatus A sensor (not-on-the-fly) is arranged on the front side of the heating device 7 on the front side of the heating device 7 on the basis of a press of a copy button or a print command signal of this apparatus, or a recording material P supporting an unfixed toner image t to be fixed Based on the signal at the time of detection, the rotation of the pressure roller B is started, the power supply to the heater 22 is performed, and the temperature of the heater 22 is started to rise. An image as a material to be heated is provided between the film 21 and the pressure roller B in the fixing nip portion N in a state where the rotation peripheral speed of the film 21 by the rotation of the heating roller B becomes steady and the temperature of the heater 22 rises to a predetermined level. When the recording material P to be fixed is introduced and conveyed through the fixing nip portion N together with the film 21, the heat of the heater 22 is applied to the recording material P through the film 21, and the unfixed toner image t is changed to the recording material. It is heat-fixed on the P surface. The area of the fixing nip N is an area where pressure and temperature are applied between the pressure roller B and the heater 22.

  Before the recording material P enters the fixing nip N, the film 21 is rotated by the pressure roller B, and the film 21 is rotated by the rotation of the pressure roller B. When the recording material P is conveyed into the fixing nip N, the recording material P and the film 21 are rotated by the rotation of the pressure roller B and the recording material P is conveyed. When the recording material P is introduced into the fixing nip portion N, a rotational force indirectly acts on the film 21 through the heating material P, and the film 21 is rotationally driven while being slidably pressed against the surface of the heater 22. The The holder 23 also serving as a film inner surface guide member facilitates the rotation of the film 21. The recording material P that has passed through the fixing nip N is separated from the surface of the film 21 and conveyed.

(3) Pressure roller B
FIG. 6 is a vertical cross-sectional model view of the pressure roller B in the present embodiment. This pressure roller B is a hollow type elastic pressure roller according to the present invention, and includes a metal shaft 31 as a shaft member, and an elastic roller portion 32 such as silicon rubber provided substantially concentrically around the metal shaft 31. The elastic roller portion 32 is an airtight hollow body, and is a pressure roller characterized in that gas is sealed so that an internal pressure of a certain level or more is applied in the hollow. That is, the pressure roller B is configured such that air is press-fitted in a hollow state and pressure is applied from the inside to the surface side. The pressure roller surface is made of a flexible material and is configured to maintain a constant nip width by a constant pressure.

  The metal shaft 31 as a shaft member (core metal) is an iron round bar having an outer diameter of 10φ.

  The elastic roller portion 32 is a silicone rubber tube body having a length of 330 mm, an outer diameter of approximately 25φ, a wall thickness of 200 μm to 1000 μm, and an Asker hardness C of about 40-50. In this embodiment, the outer peripheral surface of the tube body 32 is covered with a fluororesin PFA tube having a thickness of 50 μm to provide a release layer 32a.

  33 and 33 are circular end plates constituting both end portions of the elastic roller portion 32, and are concentrically and integrally bonded to the metal shaft 31 on one end side and the other end side of the metal shaft 31 with an adhesive. . The circular end plates 33 and 33 are made of heat-resistant resin or rubber, and are made of a harder material that is more rigid than the elastic roller portion 32. The circular end plates 33 and 33 in this embodiment are made of hard silicon rubber having a thickness of 30 mm and an Asker hardness of 50 or more.

  And the metal shaft 31 which joined the circular end plates 33 * 33 in the tube 32 as an elastic roller part is inserted, and the inner peripheral part of the both ends opening part of the tube 32 is the outer peripheral part of the circular end plates 33 * 33 of each side The hollow elastic roller portion 32 is configured by integrally and airtightly bonding to each other. As the elastic roller portion, circular end plates 33 and 33 are fitted into the openings at both ends of the tube 32, respectively, and are integrally and airtightly bonded with an adhesive, and then the metal shaft 31 is inserted into the shaft holes of the circular end plates 33 and 33. The metal shaft 31 and the circular end plates 33 and 33 can be integrally and airtightly joined with an adhesive.

  Next, as indicated by a two-dot chain line in FIG. 6, the needle P for air pressure is pierced into the elastic roller portion 32 or the circular end plate 33 so that the tip of the needle is positioned in the hollow portion 34 of the elastic roller portion 32, Air is injected into the hollow portion 34 from the pneumatic input needle T to bring the internal pressure in the hollow portion of the elastic roller portion 32 to a state of about 1.5 to 3 atmospheres. Next, the pneumatic input needle T is pulled out. The needle puncture hole formed in the elastic roller portion 32 or the circular end plate 33 is small and is sufficiently crushed by the elasticity of the elastic roller portion 32 or the circular end plate 33 to self-close and press-fit in the hollow portion 34. Air does not escape from the needle puncture hole, and the internal pressure of the hollow portion 34 is kept stable for a long time. A gear G (FIGS. 2 and 3) for rotationally driving the pressure roller B is fitted and fixed to an end portion on one predetermined side of the metal shaft 31.

  Regarding the length (roller length) 300 mm of the tube 32 as the elastic roller portion, the heat generation area of the heat generation resistor (heat generation body) b of the heater 22 facing the pressure roller B is 230 mm, and both ends 50 mm are out of the heat generation area. Yes. The contact width between the circular end plates 33 and 33 constituting both ends of the elastic roller portion 32 and the metal shaft 31 is 30 mm. Therefore, the roller length is 330 mm.

  In addition, all the figures are model views showing a schematic configuration, and in the pressure roller B of FIGS. 3 to 6, the dimensional ratio relationship of members / parts constituting the pressure roller is as follows. It is not consistent with the dimensional ratio.

  As described above, the elastic roller portion 32 of the pressure roller B is formed into an airtight hollow body and gas is sealed so that an internal pressure higher than a certain level is applied to the inside of the hollow. The amount of elastic rubber in the elastic roller portion is reduced as compared with the pressure roller B ′ having the fleshy elastic roller portion 32 ′, and the heat capacity of the pressure roller can be reduced. Further, the elastic roller portion 32 made of a hollow body pressurizes gas into the hollow 34 to increase the internal pressure, so that the hollow elastic roller portion 32 has sufficient tension elasticity, and the function as a pressure roller is shown in FIG. The same function as that of the pressure roller B ′ having the conventional solid-walled elastic roller portion 32 ′ can be maintained, and a constant nip width can be maintained with the heating member by a constant pressure.

(4) Performance Test 1) Conventional Pressure Roller B ′ As shown in FIG. 7, a pressure roller B ′ having a conventional solid-walled elastic roller portion (silicon rubber material) 32 ′ is used as the pressure roller. In the heating apparatus used, a constant temperature was reached at a process speed = 150 mm / sec, a temperature control temperature = 180 ° C., an input power = 600 W, and the temperature detection element d (FIG. 5) controlled a temperature of 180 ° C. (temperature control). ) For 10 seconds.

2) In the case of the pressure roller B of Example 1 On the other hand, in the heating apparatus using the hollow type pressure roller B (internal pressure 2 atm) according to the present invention described in the above (3) as the pressure roller, the above 1 ) Under the same conditions (process speed = 150 mm / sec, temperature control temperature = 180 ° C., input power = 600 W), it took 6.5 seconds for the temperature detection element d (FIG. 5) to start the temperature control.

  That is, the rise time can be shortened by 3.5 seconds. In this embodiment, when the rise time is 10 seconds (the same rise time as in the prior art), the input power may be 485 W, and the power can be reduced by about 19%.

  This is shown in FIG. In the conventional example, it takes 10 seconds as shown by a broken line (1) in the figure until the power is first turned on and the temperature control at 180 ° C. is started, and power consumption of 430 to 450 W is consumed after the temperature control is started. doing.

  On the other hand, as shown by the solid line (2) in the power data result in this example, the temperature adjustment is started in about 6.5 seconds. Furthermore, the power at the start-up for starting up in 10 seconds with the same configuration is about 485 W as shown by the solid line (3), and there is no difference in the power after the start of temperature control, but the power at the start-up is reduced. is made of.

  Further, when the magnitude of the heat capacity is quantified for each component, the power at the start-up is as follows in this embodiment.

  The breakdown of 600W was as follows: heat release = 93W, heating unit (film unit) = 170W, pressure roller = 337W.

  More than half of the energy is consumed by the pressure roller. By making this pressure roller hollow, 115 W of the pressure roller can be reduced.

  As described above, it has become possible to contribute to energy saving by reducing the heat capacity of the pressure roller.

  FIG. 8 is a graph in which power is turned on 4 seconds after the start of measurement.

  9 and 10 are explanatory diagrams of the second embodiment. In this embodiment, the heating apparatus 7 of the first embodiment includes the pressure roller B, the shaft member 31, and the elastic roller portion 32 provided concentrically around the shaft member 31, and the elastic roller. The portion 32 is a hollow body, and is a pressure roller characterized in that a plurality of elastic air sac bodies 35 enclosing gas are contained in the hollow 34 so that an internal pressure of a certain level or more is applied. In this embodiment, the tube body constituting the elastic roller portion 32 is made of silicone rubber and has a thickness of 500 μm. The release layer 32a is a 10 μm thick coat layer of fluororesin. The plurality of elastic air sac bodies 35 are formed by a plurality of silicone rubbers forming an elastic hull like a balloon and sealed with air.

  Since the configuration of the pressure roller and the configuration of the heating device other than those described above are the same as those in the first embodiment, the description thereof is omitted.

  With the heating apparatus configuration of the second embodiment, the same conditions as in the first embodiment, that is, the process speed = 150 mm / sec, the temperature control temperature = 180 ° C., and the input power = 600 W, the rise time was about 7 seconds. It was. In addition, when the power is controlled so that the rise time is 10 seconds, the input power is 490 W, which is an 18% power reduction compared to the conventional 600 W.

  In this embodiment, filling the hollow portion 34 with the plurality of elastic air sac bodies 35 simply pushes a rubber bag such as a balloon containing a bag-like gas into the hollow portion 34. A plurality of elastic air sac bodies 35 made of silicone rubber are filled with a constant pressure gas. When the temperature in the hollow rises at the start of temperature control, the filled gas expands and the internal pressure of the hollow portion 34 is increased. Is above a certain level.

  FIG. 11A illustrates an explanatory diagram of the third embodiment. In this embodiment, in the pressure roller B of the first embodiment, the metal shaft 31 is a hollow shaft (iron pipe core), one end of the hollow shaft is closed, and the other end is generally used for bicycles. A bubble 36 for enclosing air is inserted into a tire, and a plurality of through holes 31a are provided in a portion of the hollow shaft corresponding to the hollow portion 34 of the elastic roller portion 32 so that the inside of the hollow shaft and the elastic roller portion are provided. 32 hollow portions 34 are communicated with each other. The tube body constituting the elastic roller portion 32 is made of silicone rubber and has a thickness of 500 μm. The release layer is a fluororesin coat layer. Reference numeral 36 a denotes a cap of the bubble 36.

  Since the configuration of the pressure roller and the configuration of the heating device other than those described above are the same as those in the first embodiment, the description thereof is omitted.

  In the pressure roller B of this embodiment, air is injected into the hollow portion 34 of the elastic roller portion 32 by connecting the air inlet of the air used for the bicycle to the bubble 36 and operating the air.

  With this configuration, even if air leaks and the internal pressure decreases due to durability, air can be easily sealed in a bicycle in a general household.

  In this embodiment, the air pressure valve 36 is attached to the configuration of the pressure roller of the first embodiment. The effect is the same as described above, and the power reduction rate is about 19%, which contributes to energy saving.

  FIG. 11B shows an explanatory diagram of the fourth embodiment. In this embodiment, in order to reinforce the tube body (silicone rubber) constituting the hollow elastic roller portion 32 in the pressure roller B of the third embodiment, a stainless steel metal having a thickness of about 50 to 80 μm is used in this embodiment. A mesh 37 is combined with a silicone rubber tube body.

  With the configuration of this embodiment, even if the internal air pressure is somewhat reduced, the rigidity of the tube body 32 is achieved by the stainless steel mesh 37 internally added to the tube body (silicone rubber) constituting the hollow elastic roller portion 32. Can be kept to some extent, and the applied pressure can be kept to some extent. Specifically, air was sealed so as to be a pressure corresponding to 2 atm, the applied pressure in the fixing nip N was 15 kgf in total pressure, and the fixing nip width in the paper conveyance direction was 6.5 to 7.5 mm. On the other hand, even if the air is reduced to about 1.5 atm due to durability, the configuration of this embodiment can maintain the nip width as it is, and the power consumption is equivalent to the stainless mesh without reducing the fixing ability. However, the power consumption was reduced by 15% compared with the pressure roller B ′ (FIG. 7) in which the conventional rubber was tightly packed.

  In addition to the metal mesh 37, a heat-resistant resin, for example, a polyimide film may be encapsulated in silicone rubber. In this embodiment, it is composed of a composite material of 100 μm-thick film and 500 μm-thick silicone rubber. I was able to give.

By adopting the composite material configuration of the fourth embodiment also for the tube body constituting the hollow elastic roller portion 32 of the first and second embodiments, the same effects as the fourth embodiment can be obtained in the first and second embodiments. Can do.
[Others]
1) The pressure roller B of the embodiment has a configuration in which the shaft member 31 and the hollow elastic roller portion 32 are integrally joined for driving the pressure roller, but the shaft member is a driven type pressure roller. A hollow elastic roller portion 32 may be mounted on the bearing 31 via a bearing member so that the hollow elastic roller portion 32 idles about the shaft member 31.

  2) Of course, the ceramic heater as the heating element 22 is not limited to the one having the illustrated configuration. A so-called back heating type ceramic heater in which the heating resistor b is provided on the surface of the heater base a opposite to the film sliding surface may be used. A heating element using a PTC (Positive Temperature Coefficient) heater, a nichrome wire, or the like may be used.

  The heating element 22 is not necessarily positioned at the fixing nip N. The film 21 as the flexible member can be heated from the inner surface side or the outer surface side of the film by any heating means.

  3) In the embodiment, the film 21 as the flexible member is a cylindrical member, and this is driven and driven by pressure roller driving. However, a driving roller and a tension roller are provided inside the endless film to drive the driving roller. By doing so, it is possible to use any rotation means such as rotating the film. Moreover, the film 21 as a flexible member can also be set as the apparatus structure made into the elongate end-web-shaped member wound by the roll, and letting this run and move through a heating body. The film 21 as the flexible member is not limited to the heat-resistant resin material, and can be a metal material, a composite material of a plurality of materials, or the like.

  4) The heating member is not limited to the heating unit made of the film of the embodiment, and may be any heating member such as a heating roller heated by a halogen heater or the like, a heating roller of an electromagnetic induction heating system, or a heating unit made of a film. can do.

  5) The heating device of the present invention is not limited to use as the image heating and fixing device of the embodiment, but is a hypothetical fixing device that temporarily fixes an unfixed image on a recording material, and a recording material carrying a fixed image is reheated to gloss, etc. It is also effective as an image heating apparatus such as a surface modification apparatus for modifying the image surface property.

  In addition, for example, a sheet pressing member such as a heat press device for removing wrinkles such as banknotes, a heat laminating device, a heating and drying device for evaporating water content such as paper, a heating device for drying used in an ink jet printer, etc. Of course, it is effective even if it is used as a heating device for processing.

  While various examples and embodiments of the present invention have been shown and described above, the spirit and scope of the present invention are not limited to the specific descriptions and figures in the present specification by those skilled in the art. It will be understood that various modifications and changes are fully described in the appended claims.

Schematic configuration diagram of an example of an image forming apparatus Front view of the heating device (image heating and fixing device) with the middle part omitted Longitudinal section model with intermediate part omitted Cross section model Expanded cross-sectional model view of the fixing nip Model of longitudinal section of pressure roller in Example 1 A longitudinal cross-sectional model view of a pressure roller having a conventional solid-walled elastic roller section Performance test results explanatory diagram Cross-sectional model diagram of pressure roller in Example 2 Model of longitudinal section of pressure roller in Example 2 Model of longitudinal section of pressure roller in Examples 3 and 4

Explanation of symbols

  A ... Heating member B ... Elastic pressure roller 31 ... Shaft member 32 ... Elastic roller part 33 ... Circular end plate part 34 ... Hollow part 35 ... Elastic air sac body 36 ...・ Air injection valve, 37 ・ ・ Reinforcing composite material

Claims (8)

  A pressure roller that forms a pressure nip portion with the heating member and sandwiches and conveys the material to be heated at the pressure nip portion; a shaft member; and an elastic roller portion provided substantially concentrically around the outer periphery of the shaft member; The pressure roller is characterized in that the elastic roller portion is an airtight hollow body, and a gas is sealed in the hollow so that an internal pressure of a certain level or more is applied.   A pressure roller that forms a pressure nip portion with the heating member and sandwiches and conveys the material to be heated at the pressure nip portion; a shaft member; and an elastic roller portion provided substantially concentrically around the outer periphery of the shaft member; The pressure roller is characterized in that the elastic roller portion is an airtight hollow body and has a valve for enclosing gas so that a certain internal pressure is applied to the hollow.   A pressure roller that forms a pressure nip portion with a heating member and sandwiches and conveys a material to be heated at the pressure nip portion, and includes a shaft member and an elastic roller portion concentrically provided around the shaft member. The pressure roller is characterized in that the elastic roller portion is a hollow body, and a plurality of elastic air sac bodies in which gas is sealed so that an internal pressure of a certain level or more is applied in the hollow.   The pressure roller according to claim 1, 2 or 3, wherein the hollow elastic roller portion is composed of a composite of a plurality of materials such as resin and metal.   A heating device that includes a heating member and a pressure roller that press-contacts the heating member to form a heating nip portion, and heats the material to be heated by nipping and heating the heated material in the heating nip portion. 5. A heating device, comprising the pressure roller according to claim 1.   The heating apparatus according to claim 5, wherein the heating member is a heating unit including a roller or a film including a heating body.   7. The heating apparatus according to claim 5, wherein the heated material is a recording material carrying an unfixed toner image.   7. The heating apparatus according to claim 5, further comprising: an image forming unit that forms and supports an unfixed toner image on a recording material; and a heat fixing unit that fixes the unfixed toner image on the recording material. An image forming apparatus, comprising: