JP2018054731A - Belt member, fixation device and image formation device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a belt member that suppresses an elastic layer from peeling on an end face when repeatedly driven to rotate while comprising a meandering suppression member.SOLUTION: A belt member 62A has: a cylindrical base material 110A; and an elastic layer 110B which is arranged on an outer peripheral surface of the base material 110A, and satisfies a condition A and a condition B when at least one end in a belt axial direction has a range of up to 20 mm from the end to the center side sectioned into 10 regions at intervals of a width of 2 mm. The condition A is that the elastic modulus [E] of the region on the most belt axially end side among the 10 sectioned regions is higher than the elastic modulus [E] of the region on the most belt axially center side, and the difference [E-E] thereof is 0.5-3.5 MPa or less. The condition B is that a difference in elastic modulus between adjacent regions of the 10 sectioned regions is 1 MPa or less.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a belt member, 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, for example, a drum-shaped photoconductor is charged, and the photoconductor is exposed to light controlled based on image information to electrostatically form the photoconductor. A latent image is formed, and the electrostatic latent image is converted into a visible image (toner image) with toner. After the toner image is transferred from the photosensitive member to a recording medium such as paper, it is fixed on the recording medium by a fixing device. Thus, an image is formed.

  The fixing device includes, for example, a pressure member that rotates and a belt member that rotates in contact with the pressure member, and presses the belt member from the inner peripheral surface toward the pressure member to apply pressure to the belt member. And a pressing member that forms a nip portion that allows a recording medium such as paper to pass between the pressure member and a fixing device that fixes the toner image on the recording medium by passing the recording medium through the nip portion. Are known.

  For example, in Patent Document 1, “a resin layer-forming coating solution is formed on a peripheral surface of a rotating columnar core by using a relatively moving nozzle to form a resin layer-forming coating film, In the method for manufacturing a tubular product in which the resin layer forming coating film is cured to form a resin layer, and then the core metal is removed to manufacture a tubular product, the resin layer is formed at both ends in the width direction of the resin layer. “A method for producing a tubular product in which a reinforcing portion is formed by a forming coating solution” is disclosed.

  Patent Document 2 states that “an endless belt that is stretched around a plurality of rollers and circulated, an endless base layer, and an elastic layer formed in the circumferential direction on the outer peripheral surface of the base layer; And the elastic layer is formed on the elastic layer main body formed on the outer peripheral surface of the base layer other than both ends in the width direction, and on the both end portions of the outer peripheral surface of the base layer, and the elastic layer An endless belt having an elastic layer end portion having a hardness higher than the hardness of the layer body is disclosed.

  Patent Document 3 states that “in a belt member used in an image forming apparatus in which an elastic layer is laminated on a base layer, the elastic layer is coated with a coating containing at least metal on the elastic layer surface at both ends in the belt width direction. A belt member formed with a protective layer for protection is disclosed.

JP 2012-91328 A JP 2013-130634 A JP 2013-130728 A

Conventionally, a belt member that is used by being rotationally driven is provided with a meandering suppression member that comes into contact with the end surface of the belt member and suppresses further movement in the belt axis direction from the viewpoint of suppressing meandering in the belt axis direction. In this state, it is driven to rotate. However, if the rotational driving is repeated with the meandering suppression member, the elastic layer may be peeled off at the end face of the belt member.
The problem of the present invention is that the elastic modulus [E _ed ] in the region closest to the belt axial end side among the regions obtained by dividing the range of 20 mm from the end in the belt axial direction to the center side with an interval of 2 mm in width, Compared to the case where an elastic layer having the same elastic modulus [E _in ] _in the region on the center side in the belt axial direction is provided, the peeling of the elastic layer that occurs at the end face when it is repeatedly rotated and driven with the meandering suppression member is suppressed. It is to provide a belt member.

The above problem is solved by the following means. That is,
The invention according to claim 1
A cylindrical substrate;
When at least one end in the belt axis direction is arranged on the outer peripheral surface of the base material and the range from the end to 20 mm is divided into 10 regions at intervals of 2 mm in width, the following conditions A and An elastic layer satisfying the following condition B;
A belt member.
Condition A: Among the ten regions divided into the ten regions, the elastic modulus [E _ed ] in the region closest to the belt axial direction end is higher than the elastic modulus [E _in ] _in the region centrally in the belt axial direction, and The difference [E _ed -E _in ] is 0.5 MPa or more and 3.5 MPa or less.
Condition B: In each of the regions divided into ten, the difference in elastic modulus between adjacent regions is 1 MPa or less.

The invention according to claim 2
The belt member according to claim 1, wherein the elastic layer contains vinyl group-containing silicone rubber.

The invention according to claim 3
The belt member according to claim 1 or 2, further comprising at least one adhesive layer of a lower adhesive layer satisfying the following condition 1 and an upper adhesive layer satisfying the following condition 2.
Condition 1: The silane having a hydrogenorganopolysiloxane structure in which the lower adhesive layer is disposed in contact with the elastic layer between the base material and the elastic layer and has a hydrogen atom bonded to a silicon atom Contains a coupling agent.
Condition 2: a surface layer is further provided on the outer peripheral surface of the elastic layer, and the upper adhesive layer is disposed in contact with the elastic layer between the elastic layer and the surface layer, and is bonded to a silicon atom. And a silane coupling agent having a hydrogen organopolysiloxane structure having hydrogen atoms.

The invention according to claim 4
The belt member according to any one of claims 1 to 3,
A pressing member that contacts and presses the inner peripheral surface of the belt member;
A pressure member that is disposed to face the pressing member across the belt member and pressurizes the outer peripheral surface of the belt member;
A meandering suppression member that is disposed on at least one end side in the belt axis direction with respect to the belt member, and that suppresses the meandering by contacting the end surface of the belt member when the belt member meanders in the belt axis direction; ,
Have
A fixing device that fixes a toner image to the recording medium by sandwiching a recording medium having an unfixed toner image formed on the surface between the belt member and the pressure member.

The invention according to claim 5
An image carrier,
Charging means for charging the surface of the image carrier;
An electrostatic latent image forming means for forming an electrostatic latent image on the surface of the charged image carrier;
Developing means for developing the electrostatic latent image formed on the surface of the image carrier with a developer containing toner to form a toner image;
Transfer means for transferring the toner image to the surface of the recording medium;
A fixing unit comprising the fixing device according to claim 4, wherein the fixing unit fixes the toner image on the recording medium.
An image forming apparatus comprising:

According to the first, second, or third aspect of the invention, in each region obtained by dividing a range of 20 mm from the end in the belt axis direction to the center side at intervals of 2 mm in width, in the region closest to the end in the belt axis direction. end surface when the elastic modulus and [E _ed], was the most elastic modulus in the region of the belt axial center side than in the case of providing the [E _in] and is equal to the elastic layer, it is rotated repeatedly in a state having a meandering prevention member The belt member which suppressed peeling of the elastic layer which arises in is provided.

According to the invention which concerns on Claim 4 or 5, the elasticity modulus in the area | region of the belt axial direction end side most among each area | region which divided | segmented the range to 20 mm from the edge of a belt axial direction to the center side by the width | variety of 2 mm. Compared to the case where only the belt member having an elastic layer having the same elastic modulus [E _in ] _in the region at the center side in the belt axial direction [E _ed ] is the same as that of the meandering member, Provided is a fixing device or an image forming apparatus that suppresses peeling of an elastic layer that occurs on an end surface of a belt member when driven to rotate.

It is a schematic cross section which shows an example of the belt member which concerns on this embodiment. It is a schematic cross section which shows another example of the belt member which concerns on this embodiment. It is a schematic cross section which shows another example of the belt member which concerns on this embodiment. 1 is a schematic configuration diagram illustrating an example of a fixing device according to an exemplary embodiment. FIG. 5 is a schematic configuration diagram of the fixing device illustrated in FIG. 4 as viewed from a conveyance direction of a recording medium. 1 is a schematic configuration diagram illustrating an example of an image forming apparatus according to an exemplary embodiment. A graph conceptually showing the elastic modulus of each region when a belt member according to the present embodiment and a conventional belt member are divided into a range of 20 mm from the end in the belt axial direction to the center side at intervals of 2 mm in width. It is. It is a graph which shows the result of having cut | disconnected the range to 20 mm from the edge of a belt axial direction to the center side about the belt member of an Example and a comparative example by the space | interval of width 2mm, and measuring the elasticity modulus of each part.

  Hereinafter, an embodiment which is an example of the present invention will be described in detail.

[Belt member]
The belt member according to the present embodiment includes at least a cylindrical base material and an elastic layer disposed on the outer peripheral surface of the base material.
The elastic layer satisfies the following condition A and the following condition B when a range of 20 mm from the end to the center side is divided into 10 regions at intervals of 2 mm with respect to at least one end in the belt axial direction.
Condition A: Among the ten regions divided into the ten regions, the elastic modulus [E _ed ] in the region closest to the belt axial direction end is higher than the elastic modulus [E _in ] _in the region centrally in the belt axial direction, and The difference [E _ed -E _in ] is 0.5 MPa or more and 3.5 MPa or less.
Condition B: In each of the regions divided into ten, the difference in elastic modulus between adjacent regions is 1 MPa or less.

  Here, the “belt axial direction” refers to a direction orthogonal to the circumferential direction of the cylindrical belt member, that is, when the endless belt member according to the present embodiment is maintained in a cylindrical shape. Refers to the axial direction of the cylinder.

Since the belt member according to the present embodiment has the above-described configuration, when the belt member meanders in the belt axial direction, the belt member repeatedly comes into contact with the end surface of the belt member and suppresses meandering. The elastic layer is prevented from peeling off at the end face when driven to rotate.
The reason is guessed as follows.

  When the belt member is rotationally driven while being supported from the inner peripheral side by a support member (for example, a belt traveling guide or a pressure pad), a force is applied in the belt axial direction so that the belt member meanders toward the end portion so as to meander. A walk may occur. Therefore, from the viewpoint of suppressing the occurrence of the belt walk within a predetermined range, an end guide member for suppressing meandering (meandering suppressing member) for suppressing the meandering by contacting the end surface of the belt member is provided. ing.

Here, an example of the rotation driving mechanism of the belt member provided with the meandering suppression member will be described.
FIG. 4 is a schematic cross-sectional view seen from the belt axial direction side showing an example in which a belt member is used as a fixing member in a fixing device for an image forming apparatus. FIG. 5 is a schematic cross-sectional view of the fixing device shown in FIG. 4 as viewed from the side orthogonal to the belt axis direction (direction in which the recording medium is conveyed).

  As shown in FIG. 4, the fixing device 60 according to the present embodiment includes a pressure roll 61 (an example of a pressure member) that is rotationally driven, a heating belt 62 (an example of a belt member), and a heating belt 62. And a pressing pad 64 (an example of a pressing member) that presses the pressure roll 61. In addition, a belt traveling guide 63 and a belt traveling auxiliary guide 66 are provided inside the heating belt 62, and the heating belt 62 is provided on the outer peripheral surfaces of the belt traveling guide 63, the belt traveling auxiliary guide 66, and the pressing pad 64. Configured to move around. Further, as shown in FIG. 5, at both ends of the heating belt 62 in the belt axial direction, a belt running end guide 72 that is supported in contact with the inner peripheral surface of the heating belt 62 and the heating belt 62 in the belt axial direction. An end guide member 71 having a meandering suppression guide 73 (an example of a meandering suppression member) disposed at a position where it abuts against the end face of the heating belt 62 when it is shifted to one side of the heating belt 62 is provided.

  In the fixing device 60, for example, the influence of the dimensional accuracy of each component, the influence of the sheet K passing through the contact portion (nip portion) between the pressure roll 61 and the heating belt 62, and the like are received from the pressure roll 61. A difference may occur in the frictional force in the belt axis direction, and a force for moving the heating belt (belt member) 62 in the belt axis direction may act. Also, the force of moving in the belt axis direction may be affected by the influence of the dimensional accuracy of the heating belt (belt member) 62 itself, the dimensional accuracy of the pressure roll 61, and the like. Then, a so-called belt walk may occur in which the heating belt (belt member) 62 meanders toward the end in the belt axial direction due to the action of such force. For this reason, the fixing device 60 is provided with meandering suppression guides (meandering suppression members) 73 outside both ends of the heating belt (belt member) 62 in the belt axial direction, and the meandering suppression guide 73 is the heating belt (belt member). By contacting the end face of 62, the heating belt (belt member) 62 is prevented from meandering further.

  However, the more the rotation of the heating belt (belt member) 62 is repeated, the more the meandering (belt walk) occurs. When the meandering occurs, the heating belt 62 pushes against the meandering suppression guide (meandering suppression member) 73. The end face of the heating belt 62 and the meandering suppression guide 73 are rotated while being rubbed against each other. When rubbing is repeated on the end surface of the heating belt 62 in this manner, wear may occur particularly in the elastic layer having a relatively low strength against rubbing among the heating belt (belt member) 62. When this wear is further advanced, when the heating belt (belt member) 62 comes into contact with the meandering suppression guide 73, the end surface is deformed so as to open outward in the radial direction, and the elasticity at the end surface of the heating belt (belt member) 62. There was a case where the layer peeled off and was damaged.

  The occurrence of peeling of the elastic layer on the end surface of the belt member is not limited to the case where the elastic layer is used in the fixing device having the above configuration. In other words, when the belt member is meandering in a state of being provided with a meandering suppression member that suppresses meandering by contacting the end surface of the belt member when meandering in the belt axis direction, the end surface of the belt member is used. In some cases, the elastic layer is worn away by rubbing between the belt and the meandering suppression member, and further, the elastic layer peels off at the end face of the belt member.

Here, in the belt member, the elastic layer has a relatively low strength against rubbing compared to other layers from the viewpoint that the elastic layer provides elasticity against the pressure applied to the belt member from the outer peripheral side. This is probably because the elastic modulus is usually set lower than that of the other layers in the belt member. For example, when used in a fixing device as shown in FIGS. 4 and 5, the belt member forms a nip portion with the pressure member, and the surface of the belt member is a toner image on the recording medium. The role which adheres to is required. Therefore, in the elastic layer, the elastic modulus is set lower than that of the other layers from the viewpoint of taking a role of bending with respect to the pressure from the pressure member.
Furthermore, since the elastic layer is generally composed of the same material, the elastic layer has the same elastic modulus at any location in the belt axial direction. Therefore, when the elastic modulus of the elastic layer in each region is measured from the end in the axial direction of the belt member to the center side at an interval of 2 mm in width, for example, the example of “B” conceptually shown in FIG. As described above, both the central side and the end portion have the same degree of elasticity and a low elastic modulus. For this reason, the elastic layer has a relatively low strength against rubbing compared to other layers, and as a result, the elastic layer peels off at the end face when the belt member is repeatedly rotated with the meandering suppression member provided. it is conceivable that.

On the other hand, the belt member according to the present embodiment satisfies the above condition A, that is, the most belt among the respective regions obtained by dividing the range from the end in the belt axis direction to the center side by 20 mm into 10 at intervals of 2 mm in width. The elastic modulus [E _ed ] in the axial end region is higher than the elastic modulus [E _in ] in the central region in the belt axial direction, and the difference [E _ed −E _in ] is in the above range. Satisfy requirements.
For example, as in the example of “A” conceptually shown in FIG. 7, the elastic modulus is high on the end side while the elastic modulus is low on the center side, that is, the elastic layer on the end face. This indicates that the sliding resistance of the is improved. Thereby, even if the belt member is meandering and the end surface of the belt member is pressed against the meandering suppression member and the both are rubbed, the abrasion of the elastic layer on the end surface of the belt member is suppressed. Therefore, deformation that spreads radially outward at the end face of the belt member with the progress of abrasion is also suppressed, and as a result, peeling of the elastic layer at the end face of the belt member is suppressed.

  On the other hand, if the elastic modulus at the center of the elastic layer in the belt axial direction is lowered and the elastic modulus at the end is increased, the above-mentioned cracks (exfoliation of the elastic layer) due to abrasion at the end face can be suppressed. it is conceivable that. However, if the change in elastic modulus from the central portion in the belt axis direction to the end portion in the elastic layer is steep, cracks may occur in the elastic layer at locations where the elastic modulus changes locally. Peeling may occur at the interface between the elastic layer and the substrate. Note that this is, for example, a low elastic modulus at the center side and a high elastic modulus at the end portion, as in the example of “C” conceptually shown in FIG. In FIG. 7, the distance from the end of the belt member is in a range from 8 mm to 10 mm to 10 mm to 12 mm), and the elastic modulus changes sharply. As described above, if there is a portion where the change in elastic modulus is steep, stress concentration occurs in this portion when the belt member is repeatedly driven to rotate, and as a result, the change in elastic modulus occurs in the elastic layer. It is thought that cracks occur at the steep locations described above. In addition, with the concentration of the stress, a shift in the interface with the base material occurs between the central side and the end side in the belt axial direction of the portion where the change in the elastic modulus is steep, and as a result, the elastic layer and the base material It is considered that peeling occurs at the interface.

In particular, in recent years, the belt member used in the fixing device has a tendency to increase the width of the nip portion from the viewpoint of increasing the fixing efficiency. In order to increase the width of the nip portion, the curvature associated with the rotation of the belt member is increased. Changes can be set large. In this case, since the bending stress applied to the belt member as it rotates increases, cracks in the elastic layer due to the concentration of the stress described above and peeling at the interface between the elastic layer and the base material also occur. It becomes easy to do.
The belt member used in the fixing device is generally provided with a pressure member that comes into contact with the outer peripheral surface of the belt member and pressurizes from the outer peripheral surface side. When the length in the axial direction is shorter than the axial length, the central portion of the belt member in the axial direction of the belt is pressed by the pressure roll, but the portions that are not pressurized are generated at both ends. The boundary between the portion pressed by the pressure roll and the portion not pressed and the portion where the elastic modulus of the elastic layer has a sharp change are both at the end in the belt axial direction. By being present, cracks in the elastic layer due to the concentration of stress described above and peeling at the interface between the elastic layer and the substrate are more likely to occur.

On the other hand, the belt member according to the present embodiment satisfies the condition B, that is, adjacent regions in each region in which the range from the end in the belt axis direction to 20 mm is divided into 10 at intervals of 2 mm in width. Satisfies the requirement that the difference in elastic modulus is within the above range.
This is because, for example, as in the example of “A” conceptually shown in FIG. 7, the elastic modulus increases toward the end while the elastic modulus is low at the center side, that is, the belt shaft in the elastic layer. It represents that the change in the elastic modulus from the center of the direction toward the end is not steep but gradually increases. As a result, even when the belt member is repeatedly driven to rotate, the stress is suppressed from being partially concentrated in the elastic layer. As a result, the occurrence of cracks in the elastic layer due to the concentration of the stress or the elastic layer Occurrence of peeling at the interface between the substrate and the substrate is suppressed.

  As described above, according to the belt member according to the present embodiment, when the belt member meanders in the belt axial direction, the belt member repeatedly rotates in a state of being provided with the meandering suppression member that contacts the end surface of the belt member and suppresses meandering. The peeling of the elastic layer that occurs at the end face when it is applied is suppressed.

-Elastic modulus of elastic layer In this embodiment, when the belt member is divided into 10 regions at intervals of 2 mm in width from the end in the belt axis direction to 20 mm from the end in the belt axis direction, The difference [E _ed -E _in ] between the elastic modulus [E _ed ] in the region and the elastic modulus [E _in ] _in the region closest to the center in the belt axial direction is 0.5 MPa or more and 3.5 MPa or less. The difference [E _ed -E _in ] is preferably 1 MPa or more and 3 MPa or less, and more preferably 1.5 MPa or more and 2.5 MPa or less.
When the difference [E _ed -E _in ] is 0.5 MPa or more, the belt member is repeatedly rotated with a meandering suppression member while obtaining good elasticity against pressure from the outer peripheral side of the belt member. It is possible to suppress peeling of the elastic layer that occurs on the end face when driven.
On the other hand, when the difference [E _ed -E _in ] is 3.5 MPa or less, a change in the elastic modulus in the belt axis direction of the elastic layer is suppressed from becoming partly steep, and cracks in the elastic layer are suppressed. And the occurrence of peeling at the interface between the elastic layer and the substrate are suppressed.

Moreover, in this embodiment, in each area | region divided into 10 said, the difference of the elasticity modulus in an adjacent area | region is 1 Mpa or less. The difference in elastic modulus between the adjacent regions is preferably 0.7 MPa or less.
When the difference in elastic modulus between adjacent regions is 1 MPa or less, the change in elastic modulus in the belt axis direction of the elastic layer is suppressed from becoming partly steep, and cracks in the elastic layer can be generated. The occurrence of peeling at the interface between the elastic layer and the substrate is suppressed.

  The region where the elastic modulus at the end of the elastic layer in the belt axial direction is higher is a region that does not contribute to image formation (fixing) particularly when the belt member is used in a fixing device in the image forming apparatus. More preferably (so-called non-image portion).

The elastic modulus of the elastic layer at the center in the belt axis direction (that is, the elastic modulus in the region other than the end where the elastic modulus is higher) is also affected by the film thickness of the elastic layer, but 2 MPa Less than 1.5 MPa, more preferably 1.5 MPa or less.
On the other hand, in the region having the highest elastic modulus at the end in the belt axis direction, the elastic modulus is preferably 2 MPa or more, more preferably 2.5 MPa or more, further preferably 3 MPa or more, and 5 MPa or more. It may be.

Here, the measurement of the elastic modulus in the elastic layer is performed as follows.
The belt member is cut out in a ring shape in the circumferential direction for a total of 10 areas ranging from the end in the belt axis direction to 20 mm in increments of 2 mm, and then the other layers such as the base material are peeled off to widen the elastic layer. Cut into a 2 mm sheet. Thereafter, the elastic modulus at 160 ° C. is measured according to JIS K7244-4 using a dynamic viscoelasticity test apparatus (manufactured by A & D Co., Ltd., DDV-01FP).
Further, the region closer to the center than the range of 20 mm from the end in the belt axis direction can be measured by following the above method after cutting out into a sheet shape having a width of 2 mm.

-Achieving method Although it does not specifically limit as a method of obtaining the belt member which satisfy | fills the said conditions A and condition B, For example, the following method is mentioned.
First, an adhesive layer (lower adhesive layer) disposed in contact with the elastic layer is provided between the elastic layer and the substrate, or a surface layer is further provided on the outer peripheral surface of the elastic layer, and the surface layer An adhesive layer (upper adhesive layer) disposed in contact with the elastic layer is provided between the elastic layer. Note that both the lower adhesive layer and the upper adhesive layer may be provided. Then, in the vicinity of the end where the elastic modulus of the elastic layer is desired to be higher, the application density of at least one of the adhesive for the lower adhesive layer and the adhesive for the upper adhesive layer is directed toward the end in the belt axial direction. By gradually increasing it, a belt member satisfying the conditions A and B can be obtained. By gradually increasing the coating density of the adhesive toward the end, it is considered that the higher the coating density, the greater the amount of adhesive that penetrates into the elastic layer and the higher the overcrosslinking density in the elastic layer. Therefore, the higher the hypercrosslinking density of the elastic layer, the higher the elastic modulus. For example, as in the example of “A” conceptually shown in FIG. 7, the elastic modulus increases toward the end in the belt axis direction. It is considered that an inclined structure can be obtained.
It should be noted that both the lower adhesive layer and the upper adhesive layer are provided, and the application density of the adhesive in both is gradually increased toward the end, thereby controlling to satisfy the condition A and the condition B. It is more preferable from the viewpoint of reducing the difference in elastic modulus in the film thickness direction of the elastic layer.

  Next, the configuration of the belt member according to the present embodiment will be described with reference to the drawings.

FIG. 1 is a schematic cross-sectional view showing an example of a belt member according to the present embodiment. Moreover, FIG.2 and FIG.3 is a schematic sectional drawing which shows another example of the belt member which concerns on this embodiment, respectively.
In addition, the same code | symbol is provided to the member which has the substantially same function throughout all the drawings, and the overlapping description may be abbreviate | omitted suitably.

As an aspect of the belt member according to the present embodiment, for example, a base member 110A, a lower adhesive layer 112 provided on the base member 110A, and a lower adhesive layer are first used as in the belt member 62A shown in FIG. An embodiment having an elastic layer 110B provided so as to be in contact with 112 and a surface layer 110C provided without an adhesive layer between the elastic layer 110B is given.
Further, like the belt member 62B shown in FIG. 2, the base 110A, the elastic layer 110B provided on the base 110A without an adhesive layer, and the upper adhesive layer provided so as to contact the elastic layer 110B The aspect which has 114 and the surface layer 110C provided on the upper side adhesive layer 114 is mentioned.
Further, as in the belt member 62C shown in FIG. 3, the base 110A, the lower adhesive layer 112 provided on the base 110A, and the elastic layer 110B provided in contact with the lower adhesive layer 112, An embodiment having an upper adhesive layer 114 provided so as to be in contact with the elastic layer 110B and a surface layer 110C provided on the upper adhesive layer 114 may be mentioned.

  1, that is, a mode in which the lower adhesive layer 112 is provided between the base 110A and the elastic layer 110B, and no adhesive layer (upper adhesive layer) is provided on the outer peripheral side of the elastic layer 110B. In this case, the surface layer may be omitted.

  Here, the components of the belt member according to the present embodiment will be described in detail. Note that the reference numerals are omitted.

(Base material)
As a base material, the thing using a resin material and a metal material is mentioned, for example. If used as a belt member in a fixing device, a material having mechanical strength, flexibility and the like is preferable, and from this viewpoint, a resin material and a metal material are preferable.

As a resin material that can constitute the base material, a resin called engineering plastic is generally mentioned.
Engineering plastics constituting the base material include, for example, fluororesin, polyimide (PI, thermosetting polyimide, thermoplastic polyimide), fluorinated polyimide, polyamideimide (PAI), polybenzimidazole (PBI), and polyetheretherketone. (PEEK), polysulfone (PSU), polyethersulfone (PES), polyphenylene sulfide (PPS), polyetherimide (PEI), wholly aromatic polyester (liquid crystal polymer), and the like. Among these, polyimide, fluorinated polyimide, polyamideimide, polyetherimide, and the like are preferable in terms of mechanical strength, heat resistance, wear resistance, chemical resistance, and the like.

  When a resin material is used, the volume resistivity may be controlled by adding and dispersing a conductive agent (carbon black or the like) to the belt member.

As a metal material which can comprise a base material, various metals, such as SUS, nickel, copper, aluminum, are mentioned, for example.
Note that a resin material and a metal material may be laminated to form a base material.

  The thickness of the substrate is not particularly limited, but for example, when used as a fixing belt, it is preferably 20 μm or more and 200 μm or less, more preferably from the viewpoint of having mechanical strength and ensuring flexibility. They are 30 micrometers or more and 150 micrometers or less, More preferably, they are 40 micrometers or more and 130 micrometers or less.

(Elastic layer)
The elastic layer is a layer provided from the viewpoint of imparting elasticity to the pressure applied to the belt member from the outer peripheral side. For example, when used as a fixing belt in an image forming apparatus, a toner image on a recording medium is used. This is a layer that plays the role of closely contacting the toner image with the surface of the belt member following the unevenness.
In the present embodiment, the elastic layer satisfies the above-described condition A and condition B.

Although the elastic modulus of the elastic layer at the center in the belt axis direction (that is, the elastic modulus in the region other than the end where the elastic modulus is higher) is affected by the film thickness of the elastic layer, it is less than 2 MPa. Preferably, 1.5 MPa or less is more preferable.
In particular, when used as a belt member in a fixing device, the above elastic modulus is less than 2 MPa, so that followability to fine irregularities by a recording medium such as paper or toner can be obtained, and uneven glossiness in an image can be obtained. Occurrence is easily suppressed.

  On the other hand, in the region having the highest elastic modulus at the end in the belt axis direction, the elastic modulus is preferably 2 MPa or more, more preferably 2.5 MPa or more, further preferably 3 MPa or more. It may be the above.

  Examples of the material of the elastic layer include fluororesin, silicone resin, silicone rubber, fluororubber, and fluorosilicone rubber. From the viewpoint of heat resistance, thermal conductivity, insulation, etc., for example, silicone rubber is preferable. Further, by using silicone rubber for the elastic layer, it becomes easier to control the difference in elastic modulus when controlling the difference in elastic modulus in the belt axis direction in the elastic layer by the application density of the adhesive as described above.

  As the silicone rubber, those mainly having an addition reaction type as a crosslinked form are preferable. Silicone rubber is known for various types of functional groups, such as dimethyl silicone rubber having a methyl group, methyl phenyl silicone rubber having a methyl group and a phenyl group, vinyl silicone rubber having a vinyl group (vinyl group-containing silicone rubber). Etc.) are preferred. A vinyl silicone rubber having a vinyl group is more preferable, and a silicone rubber having an organopolysiloxane structure having a vinyl group and a hydrogen organopolysiloxane structure having a hydrogen atom (SiH) bonded to a silicon atom is more preferable.

  In the present embodiment, in the elastic material included in the elastic layer, it is preferable that silicone rubber is a main component (that is, 50% or more in mass ratio), and the content is 90% by mass or more. Is more preferably 99% by mass or more.

  You may mix | blend a filler with an elastic layer further. In particular, when used as a belt member in a fixing device, a filler is preferably blended from the viewpoints of reinforcement, heat resistance, heat transfer, and the like. As the inorganic filler, known ones are used, and examples thereof include fumed silica, crystalline silica, iron oxide, alumina, silicon metal, carbide (for example, carbon black, carbon fiber, carbon nanotube, etc.). .

  For example, the thickness of the elastic layer is preferably in the range of 50 μm to 600 μm, and more preferably in the range of 100 μm to 400 μm.

(Lower adhesive layer and upper adhesive layer)
An adhesive layer (a lower adhesive layer and an upper adhesive layer) may be interposed between the base material and the elastic layer and between the elastic layer and the surface layer from the viewpoint of improving the adhesion between the two layers. .

  Examples of the adhesive used for the adhesive layer (the lower adhesive layer and the upper adhesive layer) include a silane coupling agent adhesive, a silicone adhesive, an epoxy resin adhesive, and a urethane resin adhesive. It is done.

Among these, a silane coupling agent adhesive is more preferable. By using a silane coupling agent adhesive for the adhesive layer (lower adhesive layer and upper adhesive layer), the difference in elastic modulus in the belt axis direction of the elastic layer is controlled by the adhesive application density as described above. Furthermore, it becomes easier to control the difference in elastic modulus.
Examples of silane coupling agent adhesives include vinyl group silane coupling agents, epoxy group silane coupling agents, amino group silane coupling agents, methacryl group silane coupling agents, and styryl group silane coupling agents. Silane coupling agents having a hydrogenorganopolysiloxane structure having an amino group-based silane coupling agent and a hydrogen atom having a hydrogen atom bonded to a silicon atom, among which hydrogenorgano having a hydrogen atom bonded to a silicon atom A silane coupling agent-based adhesive having a polysiloxane structure is more preferable.

  The thickness of the adhesive layer (the lower adhesive layer and the upper adhesive layer) is preferably 0.1 μm or more, more preferably in the range of 0.2 μm or more and 50 μm or less at the center in the belt axis direction. More preferably, it is in the range of 3 μm or more and 30 μm or less.

(Surface layer)
In this embodiment, the belt member may have a surface layer.
The surface layer is required to have heat resistance and releasability, for example. From this viewpoint, it is preferable to use a heat-resistant release material as the material constituting the surface layer, and specific examples include fluororubber, fluororesin, silicone resin, and polyimide resin.
Among these, a fluororesin is preferable as the heat-resistant release material.
Specific examples of such a fluororesin include tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer (PFA), polytetrafluoroethylene (PTFE), tetrafluoroethylene-hexafluoropropylene copolymer (FEP), and polyethylene. -Tetrafluoroethylene copolymer (ETFE), polyvinylidene fluoride (PVDF), polychloroethylene trifluoride (PCTFE), vinyl fluoride (PVF) and the like.

  A surface treatment may be applied to the surface of the surface layer on the elastic layer side. The surface treatment may be a wet treatment or a dry treatment, and examples thereof include liquid ammonia treatment, excimer laser treatment, and plasma treatment.

  The thickness of the surface layer is preferably in the range of 20 μm to 100 μm, for example.

(Belt member manufacturing method)
Next, the manufacturing method of a belt member is demonstrated. In this example, the surface layer is further provided on the elastic layer, the lower adhesive layer is provided between the base material and the elastic layer, and the upper adhesive layer is provided between the elastic layer and the surface layer. To. Moreover, the aspect which employ | adopted the above-mentioned method is made into an example as a means to achieve the structure whose elastic layer has a higher elasticity modulus in the edge part of a belt axial direction.

-Preparation of elastic layer forming coating liquid A liquid addition-curable silicone rubber mixture will be described as an example of a coating liquid for forming an elastic layer. First, an uncrosslinked silicone rubber is obtained by mixing an organopolysiloxane having an unsaturated bond such as a vinyl group and an organopolysiloxane having a Si-H bond. In this uncrosslinked silicone rubber, crosslinking proceeds by an addition reaction of Si—H to an unsaturated bond such as a vinyl group by heating or the like. In addition, you may contain crosslinking catalysts, such as a platinum compound which accelerates | stimulates reaction, and may contain the reinforcing filler which has OH group on the surface.

-Preparation of Adhesive A known adhesive is used as the adhesive (primer). For example, a primer mixed solution containing A liquid: alkoxysilane and B liquid: Si-H polymer will be described as an example. By applying this primer mixed solution on a base material or an elastic layer, a primer layer is formed by a hydrolysis reaction or a condensation reaction.

・ Formation of each layer Density determined by the flow coat method (spiral winding application) with an adhesive (primer) for bonding the base material and the elastic layer to the surface of the base material inserted in a metal core. Apply to a distribution and dry. That is, the primer application density at the belt axial direction end is gradually increased toward the end. Next, a liquid coating solution for forming an elastic layer (addition-curable silicone rubber mixture) diluted with a solvent is applied by a flow coating method so as to have a nearly uniform film thickness, dried, and then subjected to primary vulcanization.
When an uncrosslinked addition-curing silicone rubber mixture is applied and laminated, hydrogen bonding or condensation reaction between the OH group on the filler surface and the OH group on the primer, and the vinyl group in the silicone rubber and Si in the primer An adhesion reaction occurs due to an addition reaction between the -H group. At this time, at the end portion where the application density of the primer component is further increased, a part of the primer component penetrates into the elastic layer, and the crosslink density increases and the elastic modulus increases.

Next, an adhesive (primer) for adhering the elastic layer and the surface layer is applied so as to have a density distribution determined by a flow coating method (spiral winding application), and dried. That is, the primer application density at the belt axial direction end is gradually increased toward the end.
Note that the elastic modulus of the primer for adhesion between the elastic layer and the surface layer can be increased by increasing the coating density. However, in the case of a primer for adhesion between the elastic layer and the surface layer, it is more preferable to apply the primer after diluting it with a solvent that is permeable to silicone rubber.

  Next, a releasable tube (for example, a PFA tube) serving as a surface layer is formed along the inner surface of a hollow metal tube (outer mold) having an inner diameter larger than the outer diameter of the cylindrical body coated with the elastic layer. Expand to stick by vacuum suction. And after inserting the core metal coated with the elastic layer and the primer on the inside of the mold with the releasable tube attached to the inner surface, the vacuum suction of the outer mold is released to release the mold. The tube is coated on the elastic layer. Further, the cored bar is taken out together with the laminate, and subjected to secondary vulcanization to bond the silicone rubber of the elastic layer and the release tube (PFA tube), and complete the crosslinking of the silicone rubber. Next, the belt is taken out from the mold, and both end portions are cut so as to have a predetermined length to form a belt member.

(Use of belt member)
The belt member according to this embodiment is applied to, for example, a heating belt and a pressure belt in a fixing device for an image forming apparatus. In addition, as a heat source in a heating belt, the system heated from an external heat source, an electromagnetic induction system, etc. are mentioned.

[Fixing device]
Next, the fixing device according to this embodiment will be described.
The fixing device according to the present embodiment includes a belt member according to the above-described embodiment, a pressing member that contacts and presses the inner peripheral surface of the belt member, and the pressing member that faces the pressing member. A pressure member that pressurizes the outer peripheral surface of the belt member, and is disposed on at least one end side of the belt member in the belt axial direction with respect to the belt member, and when the belt member meanders in the belt axial direction A meandering suppression member that suppresses the meandering by contacting the end surface of the member, and the toner is sandwiched between the belt member and the pressure member, and the recording medium having an unfixed toner image formed on the surface thereof A fixing device that fixes an image on the recording medium.

Hereinafter, a fixing device including a heating belt (an example of a belt member) and a pressure roll (an example of a pressure member) will be described as an example of a fixing device according to the present embodiment. In the fixing device according to one embodiment described below, the belt member according to this embodiment is applied as a heating belt.
The fixing device according to the present embodiment is not limited to one embodiment described below, and includes an aspect including a heating belt and a pressure belt, an aspect including a heating roll and a pressure belt, and the like. Good. The belt member according to the present embodiment can be applied to both a heating belt and a pressure belt.
Further, the fixing device according to the present embodiment is not limited to the following embodiment, and may be an electromagnetic induction heating type fixing device.

  FIG. 4 is a schematic cross-sectional view of an example of the fixing device according to the present embodiment as viewed from the belt axial direction side. FIG. 5 is a schematic cross-sectional view of the fixing device shown in FIG. 4 as viewed from the direction in which the recording medium is conveyed.

  As shown in FIG. 4, the fixing device 60 according to the present embodiment includes, for example, a pressure roll 61 (an example of a pressure member) that is rotationally driven, and a heating belt 62 (an example of a belt member). Further, a pressure pad 64 (pressing member) that presses the pressure roll 61 via the heating belt 62 and forms a nip portion through which the paper K (an example of a recording medium) passes between the heating belt 62 and the pressure roll 61. 1) is provided inside the heating belt 62. Further, a belt traveling guide 63 and a belt traveling auxiliary guide 66 are provided inside the heating belt 62, and the heating belt 62 extends along the outer peripheral surfaces of the belt traveling guide 63, the belt traveling auxiliary guide 66, and the pressing pad 64. Are configured to move around. The belt traveling guide 63 and the pressing pad 64 are attached to the holder 65 inside the heating belt 62. A heating element 69 is provided as a heating source for the heating belt 62 between the belt running guide 63 and the heating belt 62.

  Further, as shown in FIG. 5, end guide members 71 are provided at both ends of the heating belt 62 in the belt axial direction. The end guide member 71 includes a belt traveling end guide 72 and a meandering suppression guide 73 (an example of a meandering suppression member). The belt traveling end guide 72 is arranged in a state where it is inserted from both ends of the heating belt 62 and is fixed to both ends of the holder 65. The outer peripheral surface of the belt traveling end guide 72 and the inner peripheral surface of the heating belt 62 are in contact with each other, and the belt traveling end guide 72 supports both ends of the heating belt 62 from the inner peripheral surface side. The meandering suppression guides 73 are arranged at a distance from each other so as to abut against the end face of the heating belt 62 during the meandering (belt walk) of the heating belt 62.

  In the fixing device 60, the pressure roll 61 is rotated in the direction of arrow S by, for example, a drive motor (not shown), and the heating belt 62 is driven by this rotation in the direction of arrow R opposite to the rotation direction of the pressure roll 61. Rotate to. That is, for example, the pressure roll 61 rotates counterclockwise in FIG. 4, whereas the heating belt 62 rotates clockwise.

  Here, each member will be described in more detail.

-Pressure roll The pressure roll 61 is, for example, a solid metal core (columnar core) 61A, a heat-resistant elastic body layer 61B disposed around the core 61A, and a heat-resistant elastic body layer 61B. It is a cylindrical roll provided with the surface layer 61C arrange | positioned around. The pressure roll 61 is not limited in its shape, structure, size and the like, and a known pressure roll is used according to the purpose.

  Both end portions of the core 61A are rotatably supported by a bearing member (not shown), for example, and a predetermined pressure is applied to the fixing belt by biasing members such as coil springs disposed at both end portions of the core 61A. It is in pressure contact.

  Examples of the material of the core 61A of the pressure roll 61 include iron, aluminum (for example, A-5052 material), a metal or alloy having high thermal conductivity such as SUS and copper, ceramics, fiber reinforced metal (FRM), and the like. It is done.

  The material of the heat-resistant elastic body layer 61B of the pressure roll 61 is, for example, rubber, elastomer, or foam having a hardness (JIS-A: hardness measured by a JIS-KA type testing machine) of 15 ° to 60 °. Examples of the resin include silicone rubber, fluorine rubber, and liquid silicone rubber filled with hollow glass beads. The thickness of the heat resistant elastic layer is not particularly limited, but is preferably in the range of 2 mm to 20 mm, and more preferably in the range of 3 mm to 10 mm.

  The material of the surface layer 61C of the pressure roll 61 may be a resin or the like. Examples of the resin for forming the surface layer 61C include tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer (PFA), polytetrafluoroethylene (PTFE), tetrafluoroethylene-, from the viewpoints of heat resistance and releasability. Fluororesin such as hexafluoropropylene copolymer (FEP), silicone resin, silicone rubber, fluororubber, and fluorinated polyimide.

The surface layer 61C preferably has conductivity, and is preferably a layer having a volume resistivity of 1 × 10 ⁴ Ωcm or less. Examples of the material for forming the conductive surface layer include resins containing conductive particles such as carbon black, graphite, and metal powder. The thickness of the surface layer is not particularly limited, but for example, a range of 10 μm to 200 μm is preferable, and a range of 20 μm to 100 μm is more preferable.

-Press pad The press pad 64 is supported by the holder 65, such as metal, inside the heating belt 62, for example. The pressing pad 64 is disposed so as to face the pressure roll 61 via the heating belt 62, presses the heating belt 62 from the inner peripheral surface of the heating belt 62 to the pressure roll 61, and the heating belt 62 and the pressure roll. A nip part through which the sheet passes is formed between

  It is sufficient that the heating belt 62 and the pressure roll 61 are relatively pressurized. Therefore, the heating belt 62 may be pressurized toward the pressure roll 61 by the pressing pad 64, and the heating belt 62 may be pressurized. The pressure roll 61 may be pressurized toward the heating belt 62 side.

  The material of the pressing pad 64 is, for example, a resin such as silicone rubber, fluororubber, polyimide resin, polyamide resin, phenol resin, PES resin (polyethersulfone), PPS resin (polyphenylene sulfide), or a metal such as iron or aluminum. Etc. The resin may further contain conductive particles such as carbon black, graphite, and metal powder.

  In order to reduce the frictional resistance between the heating belt 62 and each member in contact with the inner peripheral surface of the heating belt 62 such as the pressure pad 64, a lubricant application member may be provided inside the heating belt 62. A lubricant (for example, amino-modified silicone oil) is supplied to the inner peripheral surface of the heating belt 62 by the lubricant application member.

Further, a sliding member (not shown) may be provided between the heating belt 62 and the pressing pad 64 in order to reduce sliding resistance between the inner peripheral surface of the heating belt 62 and the pressing pad 64. The sliding member may be composed of a single layer or may be composed of a plurality of layers. Examples of the material of the sliding member include sintered PTFE resin sheets, glass fiber sheets impregnated with fluororesin, and laminated sheets in which a fluororesin film sheet is heat-sealed and sandwiched between glass fibers.
Moreover, it is preferable that a lubricant permeation preventive layer that suppresses exhaustion of the lubricant is disposed on the sliding member. Examples of the material for the lubricant permeation prevention layer include heat resistant resin films and metal films that have heat resistance and do not allow lubricant to permeate.
When the sliding member is not installed, the pressing pad 64 is made of a resin or metal containing particles capable of imparting conductivity so that the surface contacting the inner peripheral surface of the heating belt 62 has conductivity. It is preferable that it is comprised.

Belt running guide and heating element The belt running guide 63 and the belt running auxiliary guide 66 are provided in an arc shape along the shape of the heating belt 62 inside the heating belt 62, and support the heating belt 62 so that it can move around. .
The material of the belt traveling guide 63 and the belt traveling auxiliary guide 66 is, for example, heat-resistant resin such as polyphenylene sulfide (PPS), polyethylene terephthalate (PET), polybutylene terephthalate (PBT), liquid crystal polymer (LCP), and further durability. And a filler for reducing the friction coefficient added to the heat-resistant resin.

A heating element 69 is provided between the belt running guide 63 and the heating belt 62 as a heating source for applying heat to the heating belt 62.
The heating element 69 has, for example, an arc shape so as to follow the shape of the heating belt 62. As the heating element, for example, a resistance heating element that generates Joule heat by supplying electric power is sandwiched between a pair of support plates, and heat generated from the resistance heating element is applied to the heating belt 62 via the support plate. The mode transmitted is mentioned. The material of the support plate is preferably a metal such as aluminum or stainless steel from the viewpoint of heat transfer. The heating source of the fixing device 60 is not limited to a heating element, and for example, a known heating source such as a halogen lamp may be used.

End guide member The end guide member 71 is provided at both ends of the heating belt 62 in the belt axial direction, is fixed to both ends of the holder 65, and is in contact with and supported by both ends of the inner peripheral surface of the heating belt 62. And a meandering suppression guide 73 (an example of a meandering suppression member) disposed at a position where it abuts against the end surface of the heating belt 62 when the heating belt 62 meanders (belt walk). Also, a holding portion 74 is provided on the opposite side of the belt running end guide 72 with respect to the meandering suppression guide 73, and the end guide member 71 is fixed by holding the holding portion 74 on the fixing device 60. Yes.
The material of the end guide member 71 (the belt travel end guide 72, the meandering suppression guide 73, and the holding portion 74) is, for example, polyphenylene sulfide (PPS), polyethylene terephthalate (PET), polybutylene terephthalate (PBT), or liquid crystal polymer. Examples thereof include a heat-resistant resin such as (LCP) and a material obtained by further adding a filler for lowering durability and a friction coefficient to the heat-resistant resin.

  Next, the operation of the fixing device 60 will be described.

  In the fixing device 60, the pressure roll 61 is rotated in the direction of arrow S by a drive motor (not shown), for example, and the heating belt 62 is rotated in the direction of arrow R opposite to the rotation direction of the pressure roll 61 following this rotation. To do. That is, for example, the pressure roll 61 rotates counterclockwise in FIG. 4, whereas the heating belt 62 rotates clockwise. The rotation speed is not particularly limited, and is set to, for example, a surface speed of 250 mm / second.

  A sheet K (an example of a recording medium) on which the unfixed toner image G is formed is guided by a fixing inlet guide 56A and conveyed to a nip portion formed by a heating belt 62 and a pressure roll 61. The When the paper K passes through the nip portion, the toner image G on the paper K is applied with pressure and heat acting on the nip portion, and is further guided and discharged by the fixing outlet guide 56B, so that the toner image G on the surface of the paper K is discharged. Image G is fixed.

Modified Example In the fixing device 60 shown in FIGS. 4 and 5, the heating belt 62 is in contact with the toner image G on the paper (recording medium) K, that is, the heating side in which the belt member is in contact with the toner image on the recording medium. The configuration in which the pressure belt 61 is used as the pressure belt 61 that is in contact with the back side of the recording medium is described. However, the belt member and the pressure member in the fixing device according to the present embodiment are not limited to these. For example, the belt member may be used as a pressure belt that is not in contact with the toner image on the recording medium, and a heating / pressure roll having a heating source (for example, a halogen heater) inside may be used as the pressure member.

[Image forming apparatus]
Next, the image forming apparatus according to the present embodiment will be described.
The image forming apparatus of this embodiment includes an image carrier, a charging unit that charges the surface of the image carrier, and an electrostatic latent image forming unit that forms an electrostatic latent image on the charged surface of the image carrier. Developing means for developing the electrostatic latent image formed on the surface of the image carrier with a developer containing toner to form a toner image; and transfer means for transferring the toner image to the surface of the recording medium; Fixing means for fixing the toner image to the recording medium. The fixing device according to this embodiment is applied as the fixing unit.

The image forming apparatus according to the present embodiment will be described below with reference to the drawings.
FIG. 6 is a schematic configuration diagram showing the configuration of the image forming apparatus according to the present embodiment.

  As shown in FIG. 6, the image forming apparatus 100 according to the present embodiment is, for example, an intermediate transfer type image forming apparatus generally called a tandem type, and a plurality of toner images of each color component are formed by an electrophotographic system. Image forming units 1Y, 1M, 1C, and 1K, and a primary transfer unit 10 that sequentially transfers (primary transfer) the color component toner images formed by the image forming units 1Y, 1M, 1C, and 1K to the intermediate transfer belt 15. The secondary transfer unit 20 that collectively transfers (secondary transfer) the superimposed toner image transferred onto the intermediate transfer belt 15 onto the paper K that is a recording medium, and the fixing that fixes the secondary transferred image onto the paper K. Device 60. Further, the image forming apparatus 100 includes a control unit 40 that controls the operation of each device (each unit).

  This fixing device 60 is the fixing device 60 according to this embodiment described above.

  Each of the image forming units 1Y, 1M, 1C, and 1K of the image forming apparatus 100 includes a photoconductor 11 that rotates in the arrow A direction as an example of an image holding body that holds a toner image formed on the surface.

  A charger 12 for charging the photosensitive member 11 is provided around the photosensitive member 11 as an example of a charging unit, and a laser exposure device for writing an electrostatic latent image on the photosensitive member 11 as an example of a latent image forming unit. 13 (the exposure beam is indicated by Bm in the figure) is provided.

  Further, around the photosensitive member 11, as an example of a developing unit, a developing device 14 that accommodates each color component toner and visualizes the electrostatic latent image on the photosensitive member 11 with the toner is provided. A primary transfer roll 16 for transferring the color component toner images formed thereon onto the intermediate transfer belt 15 by the primary transfer unit 10 is provided.

  Further, a photoconductor cleaner 17 for removing residual toner on the photoconductor 11 is provided around the photoconductor 11, and a charger 12, a laser exposure device 13, a developing device 14, a primary transfer roll 16, and a photoconductor cleaner. Seventeen electrophotographic devices are sequentially arranged along the rotation direction of the photoconductor 11. These image forming units 1Y, 1M, 1C, and 1K are arranged substantially linearly in the order of yellow (Y), magenta (M), cyan (C), and black (K) from the upstream side of the intermediate transfer belt 15. Has been.

The intermediate transfer belt 15 as an intermediate transfer member is formed of a film-like pressure belt containing a resin such as polyimide or polyamide as a base layer and containing an appropriate amount of an antistatic agent such as carbon black. The volume resistivity is 10 ⁶ Ωcm or more and 10 ¹⁴ Ωcm or less, and the thickness is, for example, about 0.1 mm.

  The intermediate transfer belt 15 is circulated and driven (rotated) at various speeds in the direction B shown in FIG. 6 by various rolls. As these various rolls, a drive roll 31 that is driven by a motor (not shown) having excellent constant speed to rotate the intermediate transfer belt 15, and the intermediate transfer belt 15 that extends substantially linearly along the arrangement direction of the respective photoreceptors 11. A support roll 32 for supporting the intermediate transfer belt 15, a tension applying roll 33 that functions as a correction roll that applies tension to the intermediate transfer belt 15 and prevents meandering of the intermediate transfer belt 15, a back roll 25 provided in the secondary transfer unit 20, an intermediate A cleaning back roll 34 is provided in a cleaning unit that scrapes off residual toner on the transfer belt 15.

The primary transfer unit 10 includes a primary transfer roll 16 that is disposed to face the photoconductor 11 with the intermediate transfer belt 15 interposed therebetween. The primary transfer roll 16 is composed of a core body and a sponge layer as an elastic layer fixed around the core body. The core is a cylindrical bar made of a metal such as iron or SUS. The sponge layer is a sponge-like cylindrical roll formed of a blend rubber of NBR, SBR, and EPDM containing a conductive agent such as carbon black and having a volume resistivity of 10 ^7.5 Ωcm or more and 10 ^8.5 Ωcm or less.

  The primary transfer roll 16 is placed in pressure contact with the photoreceptor 11 with the intermediate transfer belt 15 in between. Further, the primary transfer roll 16 has a voltage (primary polarity) opposite to the toner charging polarity (negative polarity; the same applies hereinafter). Transfer bias) is applied. As a result, the toner images on the respective photoconductors 11 are sequentially electrostatically attracted to the intermediate transfer belt 15 so that the superimposed toner images are formed on the intermediate transfer belt 15.

  The secondary transfer unit 20 includes a back roll 25 and a secondary transfer roll 22 disposed on the toner image holding surface side of the intermediate transfer belt 15.

The back roll 25 is made of a tube of EPDM and NBR blend rubber with carbon dispersed on the surface, and the inside is made of EPDM rubber. And it is formed so that the surface resistivity may be 10 ⁷ Ω / □ or more and 10 ¹⁰ Ω / □ or less, and the hardness is set to, for example, 70 ° (Asker C: manufactured by Kobunshi Keiki Co., Ltd., the same shall apply hereinafter). The 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 a metal power supply roll 26 to which a secondary transfer bias is stably applied is disposed in contact. ing.

On the other hand, the secondary transfer roll 22 is composed of a core body and a sponge layer as an elastic layer fixed around the core body. The core is a cylindrical bar made of a metal such as iron or SUS. The sponge layer is a sponge-like cylindrical roll formed of a blend rubber of NBR, SBR, and EPDM containing a conductive agent such as carbon black and having a volume resistivity of 10 ^7.5 Ωcm or more and 10 ^8.5 Ωcm or less.

  The secondary transfer roll 22 is placed in pressure contact with the back roll 25 with the intermediate transfer belt 15 interposed therebetween. Further, the secondary transfer roll 22 is grounded and a secondary transfer bias is formed between the secondary transfer roll 22 and the back roll 25, and the secondary transfer roll 22 is grounded. The toner image is secondarily transferred onto the paper K conveyed to the transfer unit 20.

  Further, on the downstream side of the secondary transfer portion 20 of the intermediate transfer belt 15, an intermediate transfer belt that removes residual toner and paper dust on the intermediate transfer belt 15 after the secondary transfer and cleans the surface of the intermediate transfer belt 15. A cleaner 35 is provided so as to be able to contact and separate.

  The intermediate transfer belt 15, the primary transfer unit 10 (primary transfer roll 16), and the secondary transfer unit 20 (secondary transfer roll 22) correspond to an example of a transfer unit.

  On the other hand, on the upstream side of the yellow image forming unit 1Y, a reference sensor (home position sensor) 42 that generates a reference signal serving as a reference for taking image forming timings in the image forming units 1Y, 1M, 1C, and 1K. It is arranged. Further, an image density sensor 43 for adjusting image quality is disposed on the downstream side of the black image forming unit 1K. The reference sensor 42 recognizes a mark provided on the back side of the intermediate transfer belt 15 and generates a reference signal. In response to an instruction from the control unit 40 based on the recognition of the reference signal, each image forming unit 1Y, 1M, 1C, and 1K are configured to start image formation.

  Further, in the image forming apparatus according to the present embodiment, as a transport unit that transports the paper K, the paper storage unit 50 that stores the paper K, and the paper K accumulated in the paper storage unit 50 is taken out at a predetermined timing. A paper feed roll 51 that transports the paper K, a transport roll 52 that transports the paper K fed by the paper feed roll 51, a transport guide 53 that feeds the paper K transported by the transport roll 52 to the secondary transfer unit 20, and a secondary transfer A conveyance belt 55 that conveys the sheet K conveyed after the secondary transfer by the roll 22 to the fixing device 60 and a fixing entrance guide 56 that guides the sheet K to the fixing device 60 are provided.

Next, a basic image forming process of the image forming apparatus according to the present embodiment will be described.
In the image forming apparatus according to the present embodiment, image data output from an image reading device (not shown) or a personal computer (PC) (not shown) is subjected to image processing by an image processing device (not shown), and then the image forming unit 1Y. , 1M, 1C, 1K, image forming work is executed.

  In the image processing apparatus, input reflectance data is subjected to image processing such as shading correction, position shift correction, brightness / color space conversion, gamma correction, frame erasing, color editing, and moving editing. Is done. The image data that has undergone image processing is converted into color material gradation data of four colors, Y, M, C, and K, and is output to the laser exposure unit 13.

  The laser exposure unit 13 irradiates each of the photoconductors 11 of the image forming units 1Y, 1M, 1C, and 1K with, for example, an exposure beam Bm emitted from a semiconductor laser in accordance with the input color material gradation data. . In each of the photoreceptors 11 of the image forming units 1Y, 1M, 1C, and 1K, the surface is charged by the charger 12, and then the surface is scanned and exposed by the laser exposure unit 13 to form an electrostatic latent image. The formed electrostatic latent images are developed as toner images of respective colors Y, M, C, and K by the respective image forming units 1Y, 1M, 1C, and 1K.

  The toner images formed on the photoconductors 11 of the image forming units 1Y, 1M, 1C, and 1K are transferred onto the intermediate transfer belt 15 in the primary transfer unit 10 where the photoconductors 11 and the intermediate transfer belt 15 are in contact with each other. The More specifically, in the primary transfer portion 10, a voltage (primary transfer bias) having a polarity opposite to the toner charging polarity (minus polarity) is applied to the base material of the intermediate transfer belt 15 by the primary transfer roll 16, and the toner image. Are sequentially superimposed on the surface of the intermediate transfer belt 15 to perform primary transfer.

  After the toner images are sequentially primary transferred onto the surface of the intermediate transfer belt 15, the intermediate transfer belt 15 moves and the toner image is conveyed to the secondary transfer unit 20. When the toner image is conveyed to the secondary transfer unit 20, the conveyance unit rotates the paper feed roll 51 in accordance with the timing at which the toner image is conveyed to the secondary transfer unit 20. A size paper K is supplied. The paper K supplied by the paper feed roll 51 is transported by the transport roll 52, and reaches the secondary transfer unit 20 through the transport guide 53. Before reaching the secondary transfer unit 20, the sheet K is temporarily stopped, and an alignment roll (not shown) rotates in accordance with the movement timing of the intermediate transfer belt 15 that holds the toner image. And the position of the toner image are aligned.

  In the secondary transfer unit 20, the secondary transfer roll 22 is pressed against the back roll 25 via the intermediate transfer belt 15. At this time, the sheet K conveyed at the same timing is sandwiched between the intermediate transfer belt 15 and the secondary transfer roll 22. At this time, when a voltage (secondary transfer bias) having the same polarity as the toner charging polarity (negative polarity) is applied from the power supply roll 26, a transfer electric field is formed between the secondary transfer roll 22 and the back roll 25. Is done. The unfixed toner image held on the intermediate transfer belt 15 is collectively electrostatically transferred onto the paper K in the secondary transfer unit 20 pressed by the secondary transfer roll 22 and the back roll 25. The

  Thereafter, the sheet K on which the toner image has been electrostatically transferred is conveyed as it is while being peeled off from the intermediate transfer belt 15 by the secondary transfer roll 22, and is conveyed downstream of the secondary transfer roll 22 in the sheet conveyance direction. It is conveyed to the belt 55. The transport belt 55 transports the paper K to the fixing device 60 in accordance with the optimal transport speed in the fixing device 60. The unfixed toner image on the paper K conveyed to the fixing device 60 is fixed on the paper K by receiving a fixing process with heat and pressure by the fixing device 60. Then, the sheet K on which the fixed image is formed is conveyed to a paper discharge container (not shown) provided in the discharge unit of the image forming apparatus.

  On the other hand, after the transfer to the paper K is completed, the residual toner remaining on the intermediate transfer belt 15 is conveyed to the cleaning unit as the intermediate transfer belt 15 rotates, and is cleaned by the cleaning back roll 34 and the intermediate transfer belt cleaner 35. It is removed from the intermediate transfer belt 15.

  Although the present embodiment has been described above, the present invention is not limited to the above-described embodiment, and various modifications, changes, and improvements can be made.

  Hereinafter, the present invention will be described more specifically with reference to examples. However, the present invention is not limited to the following examples.

<Example 1>
In this example, a fixing belt for a fixing device corresponding to A4 paper lateral feed was manufactured.

-Base material A cylindrical polyimide base material having a diameter of 30 mm, a thickness of 60 μm, and a length of 400 mm was prepared, and the surface was roughened and inserted into a stainless steel core.

-Lower primer layer Here, a silicone primer (a silane coupling agent having a hydrogenorganopolysiloxane structure having a hydrogen atom (SiH group) bonded to a silicon atom, trade name: DY35-051, Toray Dow Corning Co., Ltd.) 0.6 g of an equal amount mixed solution of A agent and B agent was applied by flow coating. In this application, the speed on both ends in the belt axis direction is slowed so that the coating film thickness in the region of the end 12 mm is controlled from the center to the end, and the belt shaft The coating amount at the endmost part was set to be 2.5 times the central part in the direction.

Elastic layer After the silicone primer is dried, a silicone rubber comprising a liquid silicone rubber (an organopolysiloxane having a vinyl group and an organohydrogenpolysiloxane having a hydrogen atom (SiH group) bonded to a silicon atom). Raw materials, trade name: DY35-1310, Toray Dow Corning Co., Ltd.) A and B were mixed in equal amounts, and further butyl acetate was added to adjust the viscosity, followed by coating by flow coating. Subsequently, after drying the solvent, primary vulcanization was performed at 150 ° C.

Upper primer layer Next, a primer for bonding a PFA tube (the ratio of hydrogenorganopolysiloxane to vinyl groups was increased (that is, liquid silicone rubber with excessive SiH groups, trade name: SE1714, Toray Dow) Corning Co., Ltd.) was diluted with heptane, and then applied by flow coating.At this time, the speed at both ends in the belt axis direction was slowed so that the coating film thickness in the region of 12 mm from the center was The thickness is controlled so as to become thicker toward the end, and the coating thickness at the center in the belt axis direction (area corresponding to paper passing) is set to 10 μm, and the coating thickness at the end is set to 15 μm, and then dried. Carried out.

-Surface layer Next, the PFA tube (inner surface activated treatment) that becomes the surface layer has an inner diameter slightly smaller than the outer diameter of the core metal on which the base material, the lower primer layer, the elastic layer, and the upper primer layer are formed. The hollow metal tube (outer mold) having a large inner diameter was expanded so as to adhere by vacuum suction along the inner surface of the hollow metal tube (outer mold).
Next, after inserting the core metal coated with the elastic layer and coated with the upper primer layer inside the outer mold with the PFA tube attached to the inner surface, the vacuum suction of the outer mold is released to A PFA tube was coated on the elastic layer. Further, the core metal was taken out together with the laminate, and heated at 200 ° C. for 4 hours to perform secondary vulcanization, thereby bonding the silicone rubber of the elastic layer and the PFA tube, and completing the crosslinking of the silicone rubber.
Next, after removing the belt from the mold, both ends were cut to a length of 366 mm to obtain a fixing belt.

  The thickness of the elastic layer of the fixing belt was 200 μm.

-Measurement of elastic modulus With respect to the fixing belt, 10 regions were cut into a ring shape at intervals of 2 mm in the range from one end in the belt axial direction to 20 mm toward the center, and the elastic modulus of each region was determined as described above. Measured by the method. The results are shown in Table 1 below and FIG.
Since the measurement of the elastic modulus is a destructive test, a fixing belt for the following evaluation test was prepared separately under the same conditions.

<Comparative Example 1>
In the production of the fixing belt of Example 1, a fixing belt was obtained in the same manner as in Example 1 except that both the lower primer layer and the upper primer layer were applied so as to be nearly uniform over the entire surface. .
The results of elastic modulus measured in the same manner as in Example 1 are shown in Table 1 below and FIG.

<Comparative example 2>
In the production of the fixing belt of Example 1, the lower primer layer and the upper primer layer were both applied in a state where the thickness was nearly uniform in the region of both end portions 12 mm in the belt axial direction, while the center portion was larger than both end portions 12 mm. A fixing belt was obtained in the same manner as in Example 1 except that it was made thin and nearly uniform in the side region. The elastic modulus of the elastic layer was divided into a high elastic modulus portion and a low elastic modulus portion at a point where the coating film thickness of the primer changed.
The results of elastic modulus measured in the same manner as in Example 1 are shown in Table 1 below and FIG.

〔Evaluation test〕
The fixing belts obtained in the examples and comparative examples were incorporated in the fixing device shown in FIGS. 4 and 5, and the test was carried out using a bench device that rotationally drives the fixing device. A pressure roll having an outer diameter of φ30 mm was used for the fixing device. The bench device includes a motor that rotationally drives a pressure roll, a power source that heats a heater inside the fixing belt (pressure belt), a temperature sensor that detects the surface temperature of the fixing belt, and a temperature control device. The fixing belt was controlled so that the surface temperature of the fixing belt was 170 ° C., and the surface speed of the fixing belt was set to 250 mm / s.
Using this apparatus, the fixing belt was continuously rotated, and the state of the end surface of the fixing belt was visually observed over time. However, in order to create a stress environment where belt walks are likely to occur, only one side of the belt in the axial direction is cooled by blowing air with a cooling fan to create a difference in belt temperature, and one side of the fixing belt runs on the belt. It was pushed against the guide etc. The load at the nip portion was 350 N, which is 1.5 times the normal load.

-Evaluation results-
In Comparative Example 1, the elastic layer began to wear out while generating abrasion powder from the start of the evaluation test, and a trumpet-shaped deformation began to occur in the substrate in 100 hours, and cracks began to occur in the belt end surface in 200 hours.
In Comparative Example 2, there was little abrasion of the elastic layer, and no deformation was seen in the base material on the belt end surface even after 200 hours had passed. However, in 300 hours, the surface layer floated due to the peeling of the elastic layer at the boundary between the high elastic modulus portion and the low elastic layer portion at the belt axial end.
In Example 1, there was little abrasion of the elastic layer, and even after a total of 500 hours, a part of the elastic layer on the belt end face was only slightly worn. Moreover, the surface layer was not lifted by cracks in the base material or peeling of the elastic layer.

1Y, 1M, 1C, 1K Image forming unit 10 Primary transfer unit 11 Photoconductor 12 Charger 13 Laser exposure unit 14 Developer 15 Intermediate transfer belt 16 Primary transfer roll 17 Photoconductor cleaner 20 Secondary transfer unit 22 Secondary transfer roll 25 Back roll 26 Power supply roll 31 Drive roll 32 Support roll 33 Tension applying roll 34 Cleaning back roll 35 Intermediate transfer belt cleaner 40 Control unit 42 Reference sensor 43 Image density sensor 50 Paper storage unit 51 Paper feed roll 52 Transport roll 53 Transport guide 55 Transport Belt 56 Fixing entrance guide 56A Fixing entrance guide 56B Fixing exit guide 60 Fixing device 61 Pressure roll 61A Core 61B Heat resistant elastic layer 61C Surface layer 62 Heating belts 62A, 62B, 62C Belt member 63 Belt running guide 64 Press pad 65 Holder 6 Belt running auxiliary guide 69 Heat generating element 71 End guide member 72 Belt running end guide 73 Meander suppression guide 74 Holding unit 100 Image forming apparatus 110A Base material 110B Elastic layer 110C Surface layer 112 Lower adhesive layer 114 Upper adhesive layer G Unfixed Toner image K paper

Claims (5)

A cylindrical substrate;
When at least one end in the belt axis direction is arranged on the outer peripheral surface of the base material and the range from the end to 20 mm is divided into 10 regions at intervals of 2 mm in width, the following conditions A and An elastic layer satisfying the following condition B;
A belt member.
Condition A: Among the ten regions divided into the ten regions, the elastic modulus [E _ed ] in the region closest to the belt axial direction end is higher than the elastic modulus [E _in ] _in the region centrally in the belt axial direction, and The difference [E _ed -E _in ] is 0.5 MPa or more and 3.5 MPa or less.
Condition B: In each of the regions divided into ten, the difference in elastic modulus between adjacent regions is 1 MPa or less.   The belt member according to claim 1, wherein the elastic layer contains vinyl group-containing silicone rubber. The belt member according to claim 1 or 2, further comprising at least one adhesive layer of a lower adhesive layer satisfying the following condition 1 and an upper adhesive layer satisfying the following condition 2.
Condition 1: The silane having a hydrogenorganopolysiloxane structure in which the lower adhesive layer is disposed in contact with the elastic layer between the base material and the elastic layer and has a hydrogen atom bonded to a silicon atom Contains a coupling agent.
Condition 2: a surface layer is further provided on the outer peripheral surface of the elastic layer, and the upper adhesive layer is disposed in contact with the elastic layer between the elastic layer and the surface layer, and is bonded to a silicon atom. And a silane coupling agent having a hydrogen organopolysiloxane structure having hydrogen atoms. The belt member according to any one of claims 1 to 3,
A pressing member that contacts and presses the inner peripheral surface of the belt member;
A pressure member that is disposed to face the pressing member across the belt member and pressurizes the outer peripheral surface of the belt member;
A meandering suppression member that is disposed on at least one end side in the belt axis direction with respect to the belt member, and that suppresses the meandering by contacting the end surface of the belt member when the belt member meanders in the belt axis direction; ,
Have
A fixing device that fixes a toner image to the recording medium by sandwiching a recording medium having an unfixed toner image formed on the surface between the belt member and the pressure member. An image carrier,
Charging means for charging the surface of the image carrier;
An electrostatic latent image forming means for forming an electrostatic latent image on the surface of the charged image carrier;
Developing means for developing the electrostatic latent image formed on the surface of the image carrier with a developer containing toner to form a toner image;
Transfer means for transferring the toner image to the surface of the recording medium;
A fixing unit comprising the fixing device according to claim 4, wherein the fixing unit fixes the toner image on the recording medium.
An image forming apparatus comprising: