JP6540144B2 - Pressure unit for fixing device, fixing device, and image forming apparatus - Google Patents

Description

  The present invention relates to a pressure unit for a fixing device, a fixing device, and an image forming apparatus.

In an image forming apparatus such as a copying machine or a printer using an electrophotographic method, an unfixed toner image formed on a recording medium such as recording paper is fixed by a fixing device.
The fixing device has, for example, a configuration provided with a heating roller and a pressure belt disposed in contact with the heating roller, and a configuration provided with a pressure roller disposed in contact with the heating belt and the heating belt. Are known.

  For example, Patent Document 1 includes a rotating member and a roller, first biasing means for pressing the rotating member and the roller against each other, and driving means for rotating the rotating member and the roller, the rotating member And a fixing device that nips and conveys a recording member in a nip area between the rollers, and pivots the oscillating cam that receives rotational driving force from the driving means and rotates in one direction; A displacement support member that displaces the roller so as to move in and out of the rotating member, a pressure release cam sliding on the displacement support member, a one-way clutch provided on a shaft of the pressure release cam, and the one-way clutch A swing lever connected and urged to slide on the swing cam, and fluctuated according to the rotation angle of the pressure release cam so as to brake the rotation of the pressure release cam And a second biasing means for applying a biasing force to the rotary member fixed to the shaft of the pressure release cam, and when the swing cam is rotated in one direction by the rotational drive force of the drive means, The rocking lever which is in sliding contact with the rocking cam is repeatedly rocked, and the rocking of the rocking lever is transmitted to the pressure releasing cam as rotation in one direction through the one-way clutch, and the pressure releasing cam And the displacement supporting member is pushed against the biasing force of the first biasing means, the displacement supporting member and the roller are displaced, and the roller is separated from the rotating member. Is disclosed.

Patent No. 5388056

  According to the present invention, the pressure unit for the fixing device has a sliding member having a sliding surface that slides on the inner circumferential surface of the endless belt of the fixing device, and the sliding surface of the sliding member is the inner periphery of the endless belt. An object of the present invention is to provide a pressure unit for a fixing device in which generation of a sound due to sliding between a sliding member and an endless belt is suppressed as compared with the case where only a pressing member pressing on a surface is used.

The above object is solved by the following means.
The invention according to <1> is a sliding member having a sliding surface that slides on the inner circumferential surface of an endless belt of a fixing device,
A pressing member for pressing the sliding surface of the sliding member against the inner circumferential surface of the endless belt;
A vibration suppressing member which is disposed on the opposite side to the sliding member with respect to the pressing member and which suppresses the vibration generated when the sliding surface of the sliding member slides on the inner circumferential surface of the endless belt;
A pressure unit for a fixing device.

The invention according to <2> is the pressure unit for a fixing device according to <1> , wherein the pressing member has a gap.
The invention according to <3> is the pressure unit for a fixing device according to <1> or <2> , wherein the vibration suppressing member is made of an elastic material having a JISA hardness of 50 degrees or less.

The invention according to <4> is a first rotating body,
A second rotating body disposed in contact with the outer surface of the first rotating body;
Temperature raising means for raising the temperature of at least one of the first rotating body and the second rotating body;
<1> to <3> and a fixing device for pressure unit according to any one of,
And at least one of the first rotating body and the second rotating body is an endless belt, and the sliding surface of the sliding member of the fixing unit pressing unit slides on the inner circumferential surface of the endless belt. Fixing device.

The invention according to <5> is an image carrier,
Charging means for charging the surface of the image carrier;
Latent image forming means for forming a latent image on the surface of the charged image carrier;
Developing means for developing the latent image with toner to form a toner image;
A transfer unit configured to transfer the toner image to a recording medium;
A fixing unit including the fixing device according to <4> for fixing the toner image on the recording medium;
An image forming apparatus comprising:

According to the invention of <1> , the pressure unit for the fixing device includes a sliding member having a sliding surface that slides on the inner circumferential surface of the endless belt of the fixing device, and a sliding surface of the sliding member. A pressure unit for a fixing device is provided in which generation of a sound due to sliding between a sliding member and an endless belt is suppressed as compared with the case where the pressing member is configured to press the inner peripheral surface of the endless belt. .

According to the invention as set forth in <2> , a pressure unit for fixing device is provided in which the noise due to the sliding between the sliding member and the endless belt is reduced as compared with the case where the pressing member has no gap.

According to the invention which concerns on <3> , compared with the case where the said vibration suppression member is comprised with thermoplasticity or a thermosetting resin, generation | occurrence | production of the sound by sliding of a sliding member and an endless belt is suppressed A pressure unit for the fixing device.

According to the invention of <4> and <5> , a sliding member having a sliding surface that slides on the inner circumferential surface of the endless belt of the fixing device, and a sliding surface of the sliding member of the endless belt A fixing device in which the generation of sound due to the sliding between the sliding member and the endless belt is suppressed as compared to the case where the fixing unit pressure unit configured only with the pressing member pressed against the inner peripheral surface is applied, image formation An apparatus is provided.

FIG. 2 is a schematic view showing an example of the configuration of a pressure unit for a fixing device according to the present embodiment. FIG. 2 is a schematic view showing an example of the configuration of a fixing device according to the present embodiment. FIG. 6 is a schematic view showing another example of the configuration of the fixing device according to the present embodiment. FIG. 1 is a schematic view showing an example of the configuration of an image forming apparatus according to the present embodiment.

  Hereinafter, the pressure unit for fixing device, the fixing device, and the image forming apparatus according to the present embodiment will be described in detail with reference to the attached drawings. In addition, the same code | symbol may be provided to the member which has a substantially the same function through all the drawings, and the overlapping description may be abbreviate | omitted suitably.

<Pressure unit for fixing device>
The pressure unit for fixing device according to the present embodiment includes a sliding member having a sliding surface that slides on the inner circumferential surface of the endless belt of the fixing device, and a sliding surface of the sliding member inside the endless belt. A pressing member pressing against the circumferential surface, and the pressing member are disposed on the side opposite to the sliding member, and are generated when the sliding surface of the sliding member slides on the inner circumferential surface of the endless belt And a vibration suppression member that suppresses vibration.

The sliding member and the endless belt are applied by applying the pressure unit for fixing device according to the present embodiment (hereinafter sometimes referred to as “pressure unit”) to the endless belt (pressure belt or heating belt) of the fixing device. The generation of sound due to the sliding with is suppressed.
When the sliding surface of the sliding member slides on the inner circumferential surface of the endless belt (pressure belt or heating belt) in the fixing device, it is considered that vibration is caused by friction to generate a sound.
On the other hand, in the pressure unit according to the present embodiment according to the present embodiment, the vibration suppressing member is disposed on the side opposite to the sliding member with respect to the pressing member, so that the sliding member and the endless belt It is considered that the generation of sound is suppressed by suppressing the vibration due to the sliding.

FIG. 1 schematically shows an example of the configuration of a pressure unit according to the present embodiment. The pressure unit 10 shown in FIG. 1 is a sheet-like sliding member 2 (hereinafter referred to as "sliding sheet") having a sliding surface 2a that slides on the inner circumferential surface of an endless belt (not shown) of the fixing device. And the pressing member 4 for pressing the sliding surface 2a of the sliding sheet 2 against the inner peripheral surface of the endless belt, and the pressing member 4 disposed on the opposite side of the sliding sheet 2 for sliding And a sheet-like vibration suppressing member 6 (hereinafter, may be referred to as a "vibration suppressing sheet") for suppressing vibration generated when the sliding surface 2a of the sheet 2 slides with the inner circumferential surface of the endless belt. ing.
Hereinafter, each component will be described.

[Sliding member]
As a material which comprises the sliding member 2, a resin material is mentioned, for example. Specifically, for example, fluorine resin, polyimide resin, polyamide resin, polyamide imide resin, polyether ether ester resin, polyarylate resin, polyester resin and the like can be mentioned.
Among these, as a resin material which has a low coefficient of friction with respect to a member to be slid (endless belt) and is easy to control, for example, a fluorine resin can be mentioned.

Specific examples of the fluorine resin include, for example, polytetrafluoroethylene (PTFE), perfluoroalkoxyalkane (PFA), tetrafluoroethylene-hexafluoropropylene copolymer (FEP), ethylene-tetrafluoroethylene copolymer (ETFE) Or modified products thereof. It is preferable to use fully fluorinated PFA, PTFE, or FEP from the viewpoint of reducing the coefficient of friction on the sliding surface.
Moreover, as a resin material which has heat resistance and has mechanical strength, a polyimide resin is mentioned, for example.

Although the sliding member 2 may be comprised by a single | mono layer, you may be comprised by two or more layers. Specifically, for example, a sliding member of a single layer of PTFE, a sliding member of a two-layer structure composed of a layer of PTFE and a layer of polyimide resin, and a layer of PTFE being a sliding surface, etc. It can be mentioned.
In addition, the sliding member 2 may be one in which two or more layers of the same material are laminated, or one in which three or more layers are formed.

  The thickness of the sliding member 2 is selected depending on the layer configuration of the sliding member 2 and the type of the resin material, but may be, for example, 20 μm to 300 μm, and may be 50 μm to 250 μm.

The sliding member 2 may contain other additives such as a filler as needed.
Examples of the filler include fillers added for the purpose of improving conductivity, durability, and thermal conductivity.
As a specific example of a filler, a metal oxide particle, a silicate mineral, carbon black, a nitrogen compound etc. are mentioned, for example. Among these, as a filler added for the purpose of providing conductivity, for example, ketjen black, graphite, acetylene black may be mentioned. Moreover, as a filler added in order to provide thermal conductivity, graphite, copper, silver, aluminum nitride, boron nitride, and alumina are mentioned, for example. The fillers may be used alone or in combination of two or more.
As an average particle diameter of a filler, the range of 0.01 micrometer or more and 20 micrometers is mentioned, for example.
As content of a filler, the range of 0.01 mass part or more and 30 mass parts or less is mentioned with respect to 100 mass parts of resin materials which comprise a sliding member, for example.

[Pressing member]
The pressing member 4 is disposed over a region wider than the region through which the recording medium passes in the width direction of the fixing belt (heating belt or pressure belt), and the sliding member is provided over substantially the entire length of the pressing member 4 in the longitudinal direction. The sliding surface 2a of 2 is pressed against the inner peripheral surface of the fixing belt, and the fixing belt is pressed against the fixing roll (pressure roll or heating roll).
The surface of the pressing member 4 facing the fixing roll is formed on the outer peripheral surface of the fixing roll so that the nipping area N (nip portion) in which the recording medium is nipped by the fixing belt and the fixing roll is formed wide. It has a curved shape along it.

The pressing member 4 is, for example, a member made of metal, heat-resistant resin, heat-resistant rubber or the like.
Specifically, the material constituting the pressing member 4 is an elastic material such as silicone rubber or fluororubber, or heat resistance such as polyimide resin, polyphenylene sulfide (PPS), polyether sulfone (PES) or liquid crystal polymer (LCP). Resin and the like.

The pressing member 4 preferably has a void (air bubble). When the pressing member 4 has a gap, the sound generated by the sliding between the sliding member and the endless belt is absorbed by the pressing member, and the sound can be further reduced.
The voids in the pressing member 4 may have a closed cell structure or an open cell structure.

  If the porosity in the pressing member 4 (the ratio of the volume of the entire space to the pressing member) is too small, the sound absorbing effect is not sufficiently exhibited, and if the porosity is too large, the uniformity of the load on the endless belt may be reduced. . Therefore, the porosity of the pressing member 4 is preferably 10% or more and 50% or less, and more preferably 30% or more and 50% or less.

  The method for producing the pressing member having a void is not particularly limited. For example, injection molding is performed using a material obtained by blending a filler capable of forming a void such as glass beads into heat resistant resin such as polyphenylene sulfide, LCP (liquid crystal polymer), etc. It can be manufactured by carrying out.

[Vibration suppression member]
The vibration suppressing member 6 is disposed on the opposite side to the pressing member 4 with respect to the sliding member 2 (hereinafter, may be referred to as the back side), and the sliding surface 2a of the sliding member 2 is the inner periphery of the endless belt. What is necessary is to suppress the vibration generated when sliding on the surface.

The vibration suppressing member 6 is preferably disposed on the entire back surface side of the pressing member 4 from the viewpoint of effectively suppressing vibration, but may be disposed on a part of the back surface side of the pressing member 4.
In addition, another member (for example, a heat insulating member) may be disposed between the vibration suppressing member 6 and the pressing member 4 as long as the vibration suppressing effect by the vibration suppressing member 6 is obtained.

The vibration suppression member 6 is preferably made of an elastic material from the viewpoint of effectively suppressing vibration, and more preferably made of an elastic material having a JISA hardness of 50 degrees or less.
In addition, since there is a possibility that the stability of Nip will be insufficient if the JISA hardness of the elastic material constituting the vibration suppression member 6 is too low, the JISA hardness of the elastic material constituting the vibration suppression member 6 is 10 degrees or more Is preferred.

  The JISA hardness can be measured with a durometer type A hardness meter: ASKER A type manufactured by Polymer Measuring Instruments Co., Ltd. in accordance with JIS K 6253 (1997).

  As the vibration suppression member 6 has a greater thickness, a higher damping effect can be easily obtained. However, when the vibration suppression member 6 is too thick, the thickness of the entire pressure unit according to the present embodiment increases and the stability by the support member decreases. And the load uniformity on the endless belt may be reduced. Therefore, as for the thickness of a vibration suppression member, 0.1 mm or more and 2 mm or less are preferable.

  A commercially available product may be used as the vibration suppression member 6 according to the present embodiment. For example, a hypergel sheet manufactured by Excile Corporation, etc. may be mentioned.

<Fixing device>
The fixing device according to the present embodiment raises at least one of a first rotating body, a second rotating body disposed in contact with the outer surface of the first rotating body, and the first rotating body and the second rotating body. And a pressure unit for fixing device according to the present embodiment, wherein at least one of the first rotating body and the second rotating body is an endless belt, and the pressure is applied to the fixing device. The sliding surface of the sliding member of the unit slides on the inner peripheral surface of the endless belt.

  There are various configurations as a fixing device according to the present embodiment, but as a second embodiment, a fixing device provided with a heating belt and a pressure roll as the first embodiment is a heating roll, and A fixing device provided with a pressure belt will be specifically described.

[Fixing Device According to First Embodiment]
FIG. 2 is a schematic view showing an example of the configuration of the fixing device 80 according to the first embodiment.

  The fixing device 80 shown in FIG. 2 includes a pressure roller 88 (an example of a first rotating body), a heating belt 84 (an example of a second rotating body), a pressure unit, and an electromagnetic induction device 90 (a temperature raising means). And a fixing device of an electromagnetic induction heating type. The pressure unit is configured of the sliding sheet 2 (an example of the sliding member), the pressing pad 4 (an example of the pressing member), and the vibration suppression sheet 6 (an example of the vibration suppression member).

  The pressure roll 88 and the heating belt 84 are arranged such that the outer peripheral surfaces thereof are in contact with each other, and in the area where the pressure roll 88 and the heating belt 84 contact, a pinching area N (nip portion) is formed. ing.

  The pressure roll 88 has, for example, a base layer 88A, an elastic layer 88B, and a release layer 88C.

  The heating belt 84 is configured in an endless manner, for example, by laminating a base material layer, a heat generating layer that generates heat by electromagnetic induction, an elastic layer, and a release layer in order from the inner peripheral side.

  Inside the heating belt 84, a pressure unit (sliding sheet 2, pressure pad 4, vibration suppressing sheet 6) is disposed at a position facing the pressure roll 88.

  The sliding sheet 2 is formed in a sheet shape, and is disposed between the heating belt 84 and the pressing pad 4 so that the sliding surface is in contact with the inner peripheral surface of the heating belt 84 which is a slidable member. .

The pressing unit (sliding sheet 2, pressing pad 4, vibration suppression sheet 6) is supported by the support member 86, and the heating belt 84 is wound around and presses the heating belt 84 against the pressure roll 88.
For example, a lubricant supply device (not shown) which is a means for supplying a lubricant (oil) to the inner peripheral surface of the heating belt 84 may be attached upstream of the pressing pad 4.

The electromagnetic induction device 90 is disposed at a position facing the pressure roll 88 with the heating belt 84 interposed therebetween, and causes the heat generating layer of the heating belt 84 to generate heat by electromagnetic induction.
The electromagnetic induction device 90 incorporates an electromagnetic induction coil (excitation coil) 91. The electromagnetic induction device 90 applies an alternating current to the electromagnetic induction coil 91 to generate a magnetic field, changes the magnetic field in the excitation circuit, and generates an eddy current in the heat generating layer of the heating belt 84. The eddy current is converted to heat (Joule heat) by the electrical resistance of the heat generating layer, and the surface of the heating belt 84 generates heat to raise the temperature.

  When the unfixed toner image T is fixed to the sheet K (recording medium), the heating belt 84 is rotated in the direction of arrow C by a driving device (not shown), and the pressure roller 88 is heated following this rotation. It rotates in the direction opposite to the direction of rotation of the belt 84.

  The sheet K (recording medium) having the unfixed toner image T is conveyed to the nipping area N of the fixing device 80. Then, when the sheet K passes through the sandwiching area N, the toner image on the sheet K is fixed by the pressure and heat acting on the sandwiching area N.

[Fixing Device According to Second Embodiment]
FIG. 3 is a schematic view showing an example of the configuration of the fixing device 60 according to the second embodiment.

  The fixing device 60 shown in FIG. 3 includes a heating roller 61 (an example of a first rotating body), a pressure belt 62 (an example of a second rotating body), a pressure unit, and a halogen lamp 66 (an example of a temperature raising means). And. The pressure unit is configured by the sliding sheet 2 (an example of the sliding member), the pressing pads 4a and 4b (an example of the pressing member), and the vibration suppressing sheet 6 (an example of the vibration suppressing member).

  The heating roller 61 and the pressure belt 62 are disposed such that the outer circumferential surfaces are in contact with each other, and in the region where the heating roller 61 and the pressure belt 62 are in contact, a pinching region N (nip portion) where the recording medium is pinched It is formed.

The heating roll 61 is provided with a halogen lamp 66 (an example of a temperature raising means) inside. The heating source, which is the heating means, is not limited to the halogen lamp, and may be another heating member that generates heat.
A temperature sensitive element 69 is disposed in contact with the outer peripheral surface of the heating roll 61. The lighting of the halogen lamp 66 is controlled based on the temperature measurement value by the temperature sensing element 69, and the surface temperature of the heating roll 61 is maintained at the set temperature (for example, 150 ° C.).
The heating roll 61 is configured, for example, by laminating a heat resistant elastic layer 612 and a release layer 613 around a core (cylindrical core metal) 611 made of metal in this order.

  The pressure belt 62 is configured in an endless shape, and can be rotatably rotated by a pressure unit (sliding sheet 2, pressure pads 4a and 4b, vibration suppression sheet 6) and a belt travel guide 63 disposed therein. It is supported.

The pressing pad includes the front pinching member 4 a on the inlet side of the pinching area N and the peeling pinching member 4 b on the outlet side of the pinching area N.
The front sandwiching member 4a is formed in a concave shape along the outer peripheral shape of the heating roll 61, and secures the length (the distance in the sliding direction) of the sandwiching area N.
The peeling sandwiching member 4b is configured to protrude with respect to the outer peripheral surface of the heating roller 61 to cause local distortion in the heating roller 61 in the exit region of the sandwiching region N, and heat the recording medium after fixing. To facilitate peeling from the roll 61.

  The sliding sheet 2 is disposed between the pressing belt 62 and the pressing pads 4a and 4b such that the sliding surface is in contact with the inner circumferential surface of the pressing belt 62, which is a slidable member. The sliding sheet 2 is arranged to cover the front sandwiching member 4a and the peeling sandwiching member 4b in order to reduce the sliding resistance between the inner circumferential surface of the pressure belt 62 and the pressing pads 4a and 4b.

The support member 65 supports the pressure unit (the sliding sheet 2, the pressing pads 4a and 4b, and the vibration suppression sheet 6). The support member 65 is made of metal, for example.
A belt travel guide 63 is attached to the support member 65. The pressure belt 62 rotates along the belt travel guide 63.
The belt travel guide 63 may be attached with a lubricant supply device 67 which is a means for supplying a lubricant (oil) to the inner peripheral surface of the pressure belt 62.

  On the downstream side of the sandwiching area N, a peeling member 70 is provided as an auxiliary means for peeling the recording medium. The peeling member 70 includes a peeling claw 71 and a holding member 72 that holds the peeling claw 71. The peeling claw 71 is disposed in the state of coming close to the heating roll 61 in the direction (counter direction) opposite to the rotation direction of the heating roll 61.

  The heating roller 61 is rotated in the direction of arrow C by a driving device (not shown), and the pressure belt 62 is rotated in the direction opposite to the rotation direction of the heating roller 61 following the rotation.

  The sheet K (recording medium) having the unfixed toner image is guided by the fixing inlet guide 56 and conveyed to the nipping area N. Then, when the sheet K passes through the sandwiching area N, the toner image on the sheet K is fixed by the pressure and heat acting on the sandwiching area N.

<Image forming apparatus>
The image forming apparatus according to this embodiment includes an image carrier, a charging device for charging the surface of the image carrier, a latent image forming device for forming a latent image on the surface of the charged image carrier, and The developing device includes a developing device that develops a latent image with toner to form a toner image, a transfer device that transfers the toner image to a recording medium, and a fixing device according to the present embodiment that fixes the toner image to the recording medium. .

  Hereinafter, the image forming apparatus according to the present embodiment will be described using an electrophotographic image forming apparatus as an example. The image forming apparatus according to the present embodiment is not limited to the electrophotographic image forming apparatus, and is a known image forming apparatus other than the electrophotographic type (for example, an inkjet recording apparatus including an endless belt for sheet conveyance). You may

  FIG. 4 is a schematic view showing an example of the configuration of the image forming apparatus according to the present embodiment. The image forming apparatus 100 includes the fixing device 60 of the second embodiment described above. The image forming apparatus 100 may include the fixing device 80 according to the first embodiment described above, instead of the fixing device 60.

  The image forming apparatus 100 is an intermediate transfer type image forming apparatus generally called a tandem type. The image forming apparatus 100 sequentially transfers (primary transfer) image forming units 1Y, 1M, 1C, and 1K on which toner images of respective colors are formed by electrophotography and a toner image of each color on the intermediate transfer belt 15 (primary transfer). 10, a secondary transfer unit 20 for collectively transferring (secondary transfer) the superimposed toner images transferred onto the intermediate transfer belt 15 onto a sheet K serving as a recording medium, and fixing the secondary transferred image onto the sheet K And a control unit 40 that controls the operation of each device (each unit).

The image forming units 1Y, 1M, 1C and 1K are arranged in the order of 1Y (yellow unit), 1M (magenta unit), 1C (cyan unit) and 1K (black unit) from the upstream side of the intermediate transfer belt 15. , Are arranged substantially straight.
Each of the image forming units 1Y, 1M, 1C, and 1K includes a photosensitive body 11 (an example of an image carrier). The photosensitive member 11 rotates in the direction of arrow A.

  Around the photosensitive member 11, a charger 12 (an example of a charging device), a laser exposure device 13 (an example of a latent image forming device), a developing device 14 (an example of a developing device), and a primary transfer roll 16 A photosensitive body cleaner 17 is sequentially disposed along the rotational direction of the photosensitive body 11.

The charger 12 charges the surface of the photosensitive member 11.
The laser exposure unit 13 emits an exposure beam Bm to form an electrostatic latent image on the photosensitive member 11.
The developing device 14 contains toner of each color, and visualizes the electrostatic latent image on the photosensitive member 11 with the toner.
The primary transfer roll 16 transfers the toner image formed on the photosensitive member 11 to the intermediate transfer belt 15 at the primary transfer portion 10.
The photoreceptor cleaner 17 removes residual toner on the photoreceptor 11.

The intermediate transfer belt 15 is a belt made of a material obtained by adding an antistatic agent such as carbon black to a resin such as polyimide or polyamide. The intermediate transfer belt 15 has a volume resistivity of, for example, 10 ⁶ Ωcm or more and 10 ¹⁴ Ωcm or less, and a thickness of, for example, 0.1 mm.

The intermediate transfer belt 15 is supported by the drive roll 31, the support roll 32, the tension application roll 33, the back roll 25, and the cleaning back roll 34, and is circularly driven (rotated) in the direction of arrow B as the drive roll 31 rotates. .
The drive roll 31 is driven by a motor (not shown) excellent in constant speed to rotate the intermediate transfer belt 15.
The support roll 32 supports, along with the drive roll 31, the intermediate transfer belt 15 extending substantially linearly along the arrangement direction of the four photosensitive members 11.
The tension applying roll 33 functions as a correction roll that applies a constant tension to the intermediate transfer belt 15 and suppresses the meandering of the intermediate transfer belt 15.
The back roll 25 is provided in the secondary transfer unit 20, and the cleaning back roll 34 is provided in a cleaning unit that scrapes off the residual toner on the intermediate transfer belt 15.

The primary transfer roll 16 is disposed in pressure contact with the photosensitive member 11 with the intermediate transfer belt 15 interposed therebetween to form a primary transfer portion 10.
To the primary transfer roll 16, a voltage (primary transfer bias) having a polarity opposite to that of the charging polarity of the toner (minus polarity, hereinafter the same) is applied. As a result, the toner images on the respective photosensitive members 11 are electrostatically attracted to the intermediate transfer belt 15 one by one, and a toner image superimposed on the intermediate transfer belt 15 is formed.
The primary transfer roll 16 is composed of a shaft (for example, a cylindrical rod of metal such as iron or SUS) and an elastic layer (for example, a sponge layer of blend rubber compounded with a conductive agent such as carbon black) fixed around the shaft. Cylindrical roll. The primary transfer roll 16 has a volume resistivity of, for example, 10 ^7.5 Ωcm or more and 10 ^8.5 Ωcm or less.

The secondary transfer roll 22 is disposed in pressure contact with the back roll 25 with the intermediate transfer belt 15 interposed therebetween to form a secondary transfer portion 20.
The secondary transfer roll 22 forms a secondary transfer bias with the back roll 25, and secondarily transfers the toner image onto the sheet K (recording medium) conveyed to the secondary transfer unit 20.
The secondary transfer roll 22 includes a shaft (for example, a cylindrical rod of metal such as iron or SUS) and an elastic layer fixed on the periphery of the shaft (for example, a sponge layer of blend rubber compounded with a conductive agent such as carbon black) It is a constructed cylindrical roll. The secondary transfer roll 22 has a volume resistivity of, for example, 10 ^7.5 Ωcm or more and 10 ^8.5 Ωcm or less.

The back roll 25 is disposed on the back side of the intermediate transfer belt 15 to constitute a counter electrode of the secondary transfer roll 22, and forms a transfer electric field with the secondary transfer roll 22.
The back roll 25 is configured, for example, by covering a rubber substrate with a tube of blend rubber in which carbon is dispersed. The back surface roll 25 has a surface resistivity of, for example, 10 ⁷ Ω / sq or more and 10 ¹⁰ Ω / sq or less, and a hardness of, for example, 70 ° (Asker C: manufactured by Kobunshi Keiki Co., Ltd., hereinafter the same).
A metal feed roll 26 is disposed in contact with the back roll 25. The feed roll 26 applies a voltage (secondary transfer bias) having the same polarity as the charging polarity (minus polarity) of the toner, and forms a transfer electric field between the secondary transfer roll 22 and the back roll 25.

  An intermediate transfer belt cleaner 35 is provided on the downstream side of the secondary transfer portion 20 of the intermediate transfer belt 15 so as to be capable of coming into and coming out of contact with the intermediate transfer belt 15. The intermediate transfer belt cleaner 35 removes residual toner and paper dust on the intermediate transfer belt 15 after the secondary transfer.

A reference sensor (home position sensor) 42 is disposed upstream of the image forming unit 1Y. The reference sensor 42 generates a reference signal which is a reference for setting the image formation timing in each image forming unit. The reference sensor 42 recognizes a mark provided on the back side of the intermediate transfer belt 15 to generate a reference signal, and according to an instruction from the control unit 40 that recognizes the reference signal, the image forming units 1Y, 1M, 1C, 1K. Start image formation.
An image density sensor 43 for adjusting the image quality is disposed downstream of the image forming unit 1K.

The image forming apparatus 100 includes a sheet storage unit 50, a sheet supply roll 51, a conveyance roll 52, a conveyance guide 53, a conveyance belt 55, and a fixing inlet guide 56 as conveyance means for conveying the sheet K.
The sheet storage unit 50 stores the sheet K before the image formation.
The sheet feed roll 51 takes out the sheet K stored in the sheet storage unit 50.
The transport roll 52 transports the sheet K taken out by the paper feed roll 51.
The conveyance guide 53 feeds the sheet K conveyed by the conveyance roll 52 to the secondary transfer unit 20.
The conveyance belt 55 conveys the sheet K on which the image has been transferred by the secondary transfer unit 20 to the fixing device 60.
The fixing inlet guide 56 guides the sheet K to the fixing device 60.

Next, an image forming method by the image forming apparatus 100 will be described.
In the image forming apparatus 100, image data output from an image reading apparatus (not shown), a computer (not shown) or the like is subjected to image processing by an image processing apparatus (not shown) and the image forming units 1Y, 1M, 1C, 1K An imaging operation is performed.

  In the image processing apparatus, image processing such as shading correction, positional deviation correction, lightness / color space conversion, gamma correction, border elimination, color editing, movement editing and the like is performed on the inputted reflectance data. The image data subjected to the image processing is converted into color material tone data of four colors of Y, M, C, and K, and is output to the laser exposure device 13.

The laser exposure unit 13 irradiates the exposure beam Bm to each photosensitive member 11 of the image forming units 1Y, 1M, 1C, and 1K according to the input color material tone data.
The surface of each photosensitive member 11 of the image forming units 1Y, 1M, 1C, and 1K is charged by the charger 12, and then the surface is scanned and exposed by the laser exposure unit 13 to form an electrostatic latent image. The electrostatic latent image formed on each photosensitive member 11 is developed as a toner image of each color by each image forming unit.

  The toner images formed on the photosensitive members 11 of the image forming units 1Y, 1M, 1C, and 1K are transferred onto the intermediate transfer belt 15 at the primary transfer portion 10 where the photosensitive members 11 and the intermediate transfer belt 15 contact each other. Be done. In the primary transfer portion 10, a voltage (primary transfer bias) having a polarity opposite to the charging polarity (minus polarity) of the toner is applied to the intermediate transfer belt 15 by the primary transfer roll 16, and the toner images are sequentially superimposed on the intermediate transfer belt 15. Transcribed.

The toner image primarily transferred onto the intermediate transfer belt 15 is conveyed to the secondary transfer portion 20 by the movement of the intermediate transfer belt 15.
At the timing when the toner image reaches the secondary transfer unit 20, the sheet K stored in the sheet storage unit 50 is conveyed by the paper feed roll 51, the conveyance roll 52, and the conveyance guide 53, and is sent to the secondary transfer unit 20. The sheet is supplied and sandwiched between the intermediate transfer belt 15 and the secondary transfer roll 22.
Then, in the secondary transfer portion 20 in which the transfer electric field is formed, the toner image on the intermediate transfer belt 15 is electrostatically transferred (secondary transfer) onto the sheet K.

The sheet K on which the toner image has been electrostatically transferred is separated from the intermediate transfer belt 15 by the secondary transfer roll 22, and is conveyed by the conveyance belt 55 to the fixing device 60.
The sheet K conveyed to the fixing device 60 is heated and pressed by the fixing device 60, and the unfixed toner image is fixed.

  Hereinafter, the present embodiment will be specifically described by way of examples, but the present embodiment is not limited to the examples shown below.

(Production of sliding sheet A1)
Using a crosslinked PTFE sheet (manufactured by Hitachi Metals, Ltd .: Exeron XF-1B, thickness: 0.3 mm), a single-layer sliding sheet A1 was obtained.

(Preparation of pressure pad B1)
It manufactured by injection molding using heat-resistant-resin PPS (Asahi Glass RG40JA, GF40% entry) material.
(Production of pressure pad B2)
The material which mix | blended glass bead 20% per volume with heat-resistant resin PPS (Asahi Glass RG40JA, 40% of GF input) was used, and it produced by injection molding.

(Preparation of vibration suppression sheet C1)
A liquid silicone rubber material of a heat-resistant elastic body having a JISA hardness of more than 50 degrees is poured into a mold and fired at 120 ° C. for 10 minutes, and then demolded. Then, it produced by carrying out secondary vulcanization of 200 ° C 4 hours.

(Production of vibration suppression sheet C2)
A heat-resistant elastic liquid silicone rubber material having a JISA hardness of 50 ° C. or less is poured into a mold, fired at 120 ° C. for 10 minutes, and then demolded. Then, it produced by carrying out secondary vulcanization of 200 ° C 4 hours.

Example 1
The sliding sheet A1, the pressing pad B1, and the vibration suppression sheet C1 were stacked to obtain a pressing unit P1.

Example 2
The sliding sheet A1, the pressing pad B2, and the vibration suppression sheet C1 were stacked to obtain a pressing unit P2.

Example 3
The sliding sheet A1, the pressing pad B1, and the vibration suppression sheet C2 were stacked to obtain a pressing unit P3.

Comparative Example 1
(Production of pressure unit)
The sliding sheet A1 and the pressing pad B1 were stacked to obtain a pressing unit P4.

[Evaluation of sound in fixing device]
In the fixing device of A4 color printer DocuPrint C2275 manufactured by Fuji Xerox Co., Ltd., the sliding sheet of the pressure unit manufactured in each example is incorporated so as to slide on the inner peripheral surface of the fixing belt, and J paper (color copy manufactured by Fuji Xerox Paper) A3 was passed, and the sound level in the fixing device was evaluated by ear.
The loudness of the case where the pressure unit P1 of Example 1 was used was evaluated according to the following criteria.

S1: The sound is clearly smaller than in the case where the pressure unit of Example 1 is used.
S2: Similar to the sound when the pressure unit of Example 1 is used.
S3: The sound is obviously louder than the case where the pressure unit of Example 1 is used.

  The configuration and evaluation results of the pressure unit produced in each example are shown in Table 1.

1Y, 1M, 1C, 1K Image Forming Unit 2 Sliding Sheet (Example of Sliding Member)
2a Sliding surface 4 Pressing pad (an example of pressing member)
4a, 4b Pressing pad (an example of pressing member)
6 Vibration suppression sheet (an example of a vibration suppression member)
10 pressure unit 11 for fixing device photoconductor (example of image carrier)
12 Charger (example of charging device)
13 Laser exposure unit (an example of latent image forming device)
14 Developer (an example of a developing device)
15 Intermediate transfer belt (part of transfer means)
22 Secondary transfer roll (part of transfer means)
25 back roll (part of transfer means)
60 Fixing Device 61 Heating Roll (Example of First Rotatable Body)
62 Pressure belt (an example of the second rotating body)
65 Support member 66 Halogen lamp (an example of temperature raising means)
67 Lubricant Supply Device 80 Fixing Device 84 Heating Belt (Example of Second Rotator)
86 Support member 88 Pressure roll (an example of the first rotating body)
90 Electromagnetic induction device (an example of heating means)
100 Image forming apparatus K paper (an example of recording medium)

Claims (7)

A sliding member having a sliding surface that slides on the inner circumferential surface of the endless belt of the fixing device;
A pressing member having a gap and pressing the sliding surface of the sliding member against the inner circumferential surface of the endless belt;
Wherein the said slide member side of the pressing member disposed opposite, and suppresses vibration suppressing member vibrations caused when the sliding surface of the sliding member is an inner peripheral surface and the sliding of said endless belt,
A pressure unit for fixing device provided with   The pressure unit for the fixing device according to claim 1, wherein the space of the pressing member is formed of glass beads.   The pressure unit for a fixing device according to claim 1, wherein the pressing member includes an elastic material selected from the group consisting of silicone rubber and fluorine rubber.   The pressure unit for a fixing device according to any one of claims 1 to 3, wherein the vibration suppressing member is made of an elastic material having a JISA hardness of 50 degrees or less.   The pressure unit for a fixing device according to any one of claims 1 to 4, wherein the vibration suppressing member is disposed on the entire surface of the pressing member opposite to the sliding member. The first rotating body,
A second rotating body disposed in contact with the outer surface of the first rotating body;
Temperature raising means for raising the temperature of at least one of the first rotating body and the second rotating body;
A pressure unit for a fixing device according to any one of claims 1 to 5.
And at least one of the first rotating body and the second rotating body is an endless belt, and the sliding surface of the sliding member of the fixing unit pressing unit slides on the inner circumferential surface of the endless belt. Fixing device. An image carrier,
Charging means for charging the surface of the image carrier;
Latent image forming means for forming a latent image on the surface of the charged image carrier;
Developing means for developing the latent image with toner to form a toner image;
A transfer unit configured to transfer the toner image to a recording medium;
A fixing unit including the fixing device according to claim 6, which fixes the toner image on the recording medium.
An image forming apparatus comprising: