JP6998702B2 - Silicone coated sponge roller and image forming equipment using it - Google Patents

Description

The present invention relates to a silicone-coated sponge roller having excellent transport capacity for a material to be recorded and having less wear.

Conventionally, for example, a thermal roller fixing method has been adopted as a fixing means in an image forming apparatus such as a printer, a copying machine, a facsimile, and a compound machine thereof. In the thermal roller fixing method, a heating roller (fixing roller) and a pressure roller are used as a pair of basic configurations, and a recorded material (transfer material sheet, fax paper, printing) on which a toner image is carried on a pressure contact nip portion of the roller pair is used. It is common to heat-press fix the toner image on the material to be recorded by introducing paper, etc.).

As such a pressure roller, for example, Patent Document 1 discloses a pressure roller in which a fluororesin tube having a thickness of 0.1 mm or less is coated on the outer periphery of an elastic layer formed on the outer surface of a shaft body. ing.

Japanese Unexamined Patent Publication No. 08-267614

Here, in the pressure roller of Patent Document 1, since the outer periphery of the elastic layer is covered with a fluororesin tube, the toner releasability is excellent, but the friction coefficient of the surface of the pressure roller is not sufficient. It has been pointed out that the transport capacity of the recorded material decreases with the passage of time. On the other hand, it has been pointed out that when a material having a large friction coefficient is used for the surface of the pressure roller, the amount of wear increases due to the increase in the friction coefficient. Therefore, the present invention has been made in view of the above problems, and an object of the present invention is to provide a sponge roller having excellent transport capacity of a recorded material and less wear.

In view of the above problems, the inventors of the present invention have conducted diligent research. As a result, the above-mentioned problem can be solved by the silicone-coated sponge roller having a coating layer formed from a cured product of a silicone resin on the outer peripheral surface of the elastic layer and in which phenol resin particles having a predetermined average particle size are dispersed. The present invention was completed. Specifically, the present invention provides the following.

(1) It has an elastic layer formed on the outer peripheral surface of the shaft body and a coating layer formed on the outer peripheral surface of the elastic layer, and the coating layer is formed from a cured product of a silicone resin. A silicone-coated sponge roller in which phenol resin particles having an average particle diameter of 6 μm or more and 60 μm or less are dispersed in the coating layer.

(2) The silicone-coated sponge roller according to (1), wherein the average particle size of the phenolic resin particles is 6 μm or more and 15 μm or less.

(3) The silicone-coated sponge roller according to (1) or (2), wherein the thickness of the coating layer is 20 μm or more and 100 μm or less.

(4) The coating layer is formed of two silicone resin layers, and phenol resin particles having an average particle diameter of 6 μm or more and 15 μm or less are dispersed in at least the outermost silicone resin layer. The silicone-coated sponge roller according to any one of 1) to (3).

(5) The silicone-coated sponge roller according to any one of (1) to (4), wherein the average cell diameter of the elastic layer is 50 μm or more and 150 μm or less.

(6) An image forming apparatus using the silicone-coated sponge roller according to any one of (1) to (5) for a pressurizing / fixing unit.

In the silicone-coated sponge roller of the present invention, a coating layer is formed on the outer peripheral surface of the elastic layer, and the coating layer is formed from a cured product of silicone resin, so that the friction coefficient with the material to be recorded is fluorine. It is larger than a roller coated with a resin tube and has excellent transport capacity for the material to be recorded. Further, the silicone-coated sponge roller of the present invention has a smaller coefficient of friction with the recorded material than the sponge roller before silicone coating, and is excellent in peelability from the recorded material. Further, in the silicone-coated sponge roller of the present invention, phenol resin particles having a predetermined average particle size are dispersed in the coating layer, so that the coating layer is effectively suppressed from being worn even when used for a long period of time. be able to.

It is a perspective view of the silicone-coated sponge roller of this invention.

Hereinafter, the present invention will be described in detail with reference to the drawings.

<Silicone coated sponge roller>
The silicone-coated sponge roller 1 of the present invention has an elastic layer 3 formed on the outer peripheral surface of the shaft body 2 and a coating layer 4 formed on the outer peripheral surface of the elastic layer 3.

[Axis body]
As the shaft body 2, preferably, a shaft body having a conductive property and used for a conventionally known sponge roller can be used. The shaft body 2 is preferably made of at least one metal selected from the group consisting of, for example, iron, aluminum, stainless steel, and brass. It should be noted that such a shaft body 2 is also generally known by the name of "core metal".

The shaft body 2 may contain an insulating resin. The insulating resin may be, for example, a thermoplastic resin or a thermosetting resin. The shaft body 2 may include, for example, a core body made of an insulating resin and a plating layer provided on the core body. Such a shaft body 2 can be obtained, for example, by plating a core body made of an insulating resin to make it conductive.

The shaft body 2 is preferably a core metal in order to obtain good conductive properties.

The shape of the shaft body 2 is preferably, for example, a rod shape, a tubular shape, or the like. The cross-sectional shape of the shaft body 2 may be, for example, a circular shape, an elliptical shape, or a non-circular shape such as a polygon. The outer peripheral surface of the shaft body 2 may be subjected to a treatment such as a cleaning treatment, a degreasing treatment, and a primer treatment.

The length of the shaft body 2 in the axial direction is not particularly limited, and may be appropriately adjusted according to the form of the image forming apparatus to be installed. Further, the diameter of the shaft body 2 (diameter of the circumscribed circle) is not particularly limited, and may be appropriately adjusted according to the form of the image forming apparatus to be installed.

[Elastic layer]
The elastic layer 3 is formed on the outer peripheral surface of the shaft body 2 as an elastic layer having cells inside thereof. Since the elastic layer 3 has a cell, the hardness of the elastic layer 3 can be reduced. Here, the cell included in the elastic layer 3 refers to a hollow region generated by foaming or decomposition of a foaming agent contained in the foamed silicone rubber composition capable of forming the elastic layer 3. The plurality of cells of the elastic layer 3 are in a state where they do not touch or communicate with other cells (independent cell state), a state in which they communicate with other cells (communication cell state), or an independent cell. Any state in which the state and the communication cell state coexist may be used.

(Average cell diameter)
The cell existing in the elastic layer 3 preferably has an average cell diameter of 50 μm or more and 150 μm or less, and more preferably 60 μm or more and 120 μm or less. Since the average cell diameter of the elastic layer 3 is within the above range, when the silicone resin forming the coating layer 4 is applied to the outer peripheral surface of the elastic layer 3, a non-uniform surface uneven state due to the opening cell is relatively present. A uniform surface shape, preferably a substantially uniform surface unevenness state having shallow recesses is obtained, and as a result, the formed coating layer 4 has a surface state having a substantially uniform surface unevenness with a small degree of surface unevenness.

The average cell diameter of the elastic layer 3 is about 20 mm ² on the cut surface when the elastic layer 3 is cut on an arbitrary surface by observing with an electron microscope or the like, and the maximum opening in each cell existing in the observation field. The length can be measured and the maximum measured length can be calculated as the average length obtained by arithmetically averaging. The average cell diameter of the cell is the type and content of the foaming agent contained in the foamed silicone rubber composition described later forming the elastic layer 3, the content of the reaction control agent contained in the foamed silicone rubber composition, or the foamed silicone. It can be adjusted depending on the curing conditions of the rubber composition and the like.

(Form of elastic layer)
The form of the elastic layer 3 is not particularly limited, and may be, for example, a straight shape adjusted to a uniform outer diameter along the axial direction, and the outer diameter at the central portion may be larger than the outer diameter at both ends thereof. It may be a crown shape adjusted to, or an inverted crown shape adjusted so that the outer diameter at the central portion is smaller than the outer diameter at both ends thereof.

The thickness of the elastic layer 3 is not particularly limited, but is usually adjusted to 2 mm or more and 20 mm or less.

The elastic layer 3 is a tubular body formed of "sponge-like" silicone rubber on the outer peripheral surface of the shaft body 2. The elastic layer 3 is basically formed of a foamed silicone rubber composition containing a mirrorable silicone rubber, a cross-linking agent, an unexpanded microballoon, and a chemical foaming agent.

(Mirable silicone rubber)
Mirable type silicone rubber is similar to natural rubber and unvulcanized compound rubber of ordinary synthetic rubber in the state before curing, and can be plasticized and mixed with a kneading roll machine or a closed type mixer or the like. Silicone rubber compound.

A suitable mirabable silicone rubber contains the following components (A) to (E).

(A) Organopolysiloxane R ¹ _a SiO _{(4-a) / 2} (I) having a degree of polymerization of 100 or more represented by the following average composition formula (I)
(In the formula, R ¹ represents the same or different unsubstituted or substituted monovalent hydrocarbon group, and a is a positive number from 1.95 to 2.05.)
(B) Reinforcing silica having a specific surface area of 50 m ² / g or more by the BET adsorption method (C) Alkoxysilane represented by the following general formula (II) ^R2 _m Si (OR ³ ) _4-m (II)
(In the formula, R ² is an independently hydrogen atom or an unsubstituted or substituted monovalent hydrocarbon group, R ³ is the same or different unsubstituted or substituted alkyl group, and m is 0, 1, 2 or 3)
(D) Water (E) Hexaorganodisilazane represented by the following general formula (III) R ⁴ ₃ SiNHSiR ⁴ ₃ (III)
(In the formula, ^R4 represents the same or different monovalent hydrocarbon group.)

(Crosslinking agent)
As the cross-linking agent, an addition reaction cross-linking agent and / or an organic peroxide type cross-linking agent can be used.

As the addition reaction cross-linking agent, for example, organohydrogenpolysiloxane known as an addition reaction type cross-linking agent having two or more SiH groups (SiH bonds) in one molecule can be preferably mentioned. The addition reaction cross-linking agent may be used alone or in combination of two or more.

The organic peroxide cross-linking agent can be used alone to cross-link the mirable type silicone rubber, but when used in combination as an auxiliary cross-linking agent for the addition reaction cross-linking agent, the physical properties such as strength and strain of the obtained sponge roller are further improved. Can be improved. Examples of the organic peroxide cross-linking agent include benzoyl peroxide, bis-2,4-dichlorobenzoyl peroxide, dicumyl peroxide, di-t-butyl peroxide, and 2,5-dimethyl-2,5-bis. (T-Butylperoxy) Hexane and the like can be mentioned. The organic peroxide cross-linking agent may be used alone or in combination of two or more.

When an addition reaction cross-linking agent is used, it is preferable to use an addition reaction catalyst in combination. Examples of the addition reaction catalyst include platinum black, second platinum chloride, platinum chloride acid, a reaction product of platinum chloride acid and a monohydric alcohol, a complex of platinum chloride acid and olefins, platinum bisacetoacetate, a palladium-based catalyst, and rhodium. A system catalyst and the like can be mentioned. The blending amount of this addition reaction catalyst may be the amount of the catalyst.

(Uninflated microballoon)
An unexpanded microballoon can be used to form the elastic layer 3. The unexpanded microballoon may be a non-inflated resin microballoon.

As the resin microballoon, one using a thermoplastic resin for the outer shell is preferably used. Examples of the thermoplastic resin constituting the outer shell include vinylidene chloride / acrylonitrile copolymer, methyl methacrylate / acrylonitrile copolymer, and metaacrylonitrile / acrylonitrile copolymer. It is preferable to use a resin microballoon in which the softening temperature of the resin to be the outer shell is within an appropriate range according to the curing temperature of the silicone rubber. Further, examples of the contained evaporative substance include hydrocarbons such as butane and isobutane.

In the present invention, in order to obtain the elastic layer 3 having a predetermined average cell diameter, it is preferable to use the resin microballoon alone as the foaming agent without using the chemical foaming agent described later.

(Chemical foaming agent)
A chemical foaming agent can also be used to form the elastic layer 3. The chemical foaming agent in the present invention may be any foaming agent conventionally used for forming the elastic layer 3. Examples of the inorganic foaming agent include sodium bicarbonate, ammonium carbonate and the like, and organic foaming. Examples of the agent include organic azo compounds such as a diazoamino derivative, an azonitrile derivative, and an azodicarboxylic acid derivative. Among the organic azo compounds, it is preferable to use azodicarboxylic acid amide, azobis-isobutyronitrile and the like.

[Coating layer]
The coating layer 4 is formed on the outer peripheral surface of the elastic layer 3 and is formed of a cured product of a silicone resin. Phenol having an average particle diameter of 6 μm or more and 60 μm or less in the coating layer 4 is formed. Resin particles are dispersed.

(Thickness of coating layer)
The thickness of the coating layer 4 thus formed is preferably 20 μm or more and 100 μm or less, and more preferably 30 μm or more and 70 μm or less. When the thickness of the coating layer 4 is within the above range, the elastic layer 3 can be sufficiently coated to maintain good toner releasability, and the cost of the silicone-coated sponge roller 1 can be increased. do not have.

Here, since the composition containing the silicone resin for forming the coating layer 4 has high fluidity, in order to form the coating layer 4 having the above-mentioned thickness, the coating layer 4 is divided into two silicone resin layers. It is preferable to form from. In this case, it is preferable that the phenol resin particles described later are dispersed in at least the outermost silicone resin layer, and the average particle size of the phenol resin particles dispersed in the outermost silicone resin layer is 6 μm or more and 15 μm. The following is preferable.

The thickness of the coating layer 4 is obtained from the outer diameter of the elastic layer 3 and the outer diameter of the silicone-coated sponge roller 1. Specifically, for example, the laser scan meter "LSM-6000" is used for a total of three points (measurement points) of the elastic layer 3 at the central portion in the axial direction and near the ends 10 mm from both ends in the axial direction to the central portion side. The outer diameter (arithmetic average value) of the elastic layer 3 measured using (Mitutoyo Co., Ltd.) and the silicone-coated sponge roller measured at three points corresponding to the measurement points in the same manner as the outer diameter of the elastic layer 3. The thickness of the coating layer 4 can be measured by dividing the difference from the outer diameter (arithmetic average value) of 1 by 2. The outer diameter of the elastic layer 3 may be measured before forming the coating layer 4 or after removing the coating layer 4 from the silicone-coated sponge roller 1 by polishing or the like.

(Composition containing silicone resin)
The coating layer 4 is formed from a silicone rubber composition excluding the foaming agent from the foamed silicone rubber composition used for forming the elastic layer 3, and in the present specification, this is referred to as "a composition containing a silicone resin". ". The composition containing this silicone resin is basically the same as the foamed silicone rubber composition for forming the elastic layer 3 except that it does not contain a chemical foaming agent which is a foaming agent and an unexpanded microballoon. It basically contains a silicone rubber and a cross-linking agent. For details on these, refer to the description in the elastic layer 3 described above. The coating layer 4 and the elastic layer are formed from a composition having the same composition as the elastic layer 3 except that the coating layer 4 does not contain a foaming agent and contains phenol resin particles described later. Adhesion with 3 is good.

(Phenol resin particles)
In the present invention, phenol resin particles having an average particle diameter of 6 μm or more and 15 μm or less are dispersed in the coating layer 4. By dispersing the phenol resin particles, the wear resistance of the coating layer 4 can be improved, and as a result, the long-term stain resistance of the silicone-coated sponge roller 1 can be realized.

(Sphericity)
As the phenol resin particles, those having a sphericity of 0.7 or more may be used, those having a sphericity of 0.8 or more and 1 or less, and those having a sphericality of 0.85 or more and 1 or less may be used. By using a material having a higher degree of sphericity, the uniformity and strength of the phenol resin particles become excellent.

Here, the degree of sphere is a value obtained by "the diameter of a circle equal to the projected area of the particle" / "the diameter of the smallest circle circumscribing the projected image of the particle", and the closer this value is to 1, the more true it is. Indicates that the particles are close to a sphere. "Diameter of a circle equal to the projected area of a particle" and "Diameter of the smallest circle circumscribing a projected image of a particle" are defined by a microscope and image analysis software (for example, Microscope VH-5000 manufactured by Keyence Co., Ltd. and VH-5000 manufactured by the same company, respectively. It can be obtained by soft VH-H1A5).

When the phenolic resin particles used in the present invention have a predetermined sphericity, the sphericality of commercially available phenolic resin particles may be measured and the desired sphericality may be selected and used, or commercially available ones may be used. The sphericity of the particles may be adjusted to a desired value before use. The sphericity can be adjusted by polishing, and a commercially available polishing machine (KM polisher manufactured by Kansai Matek Co., Ltd., etc.), a commercially available rice milling machine, or the like can be used depending on the hardness of the particles.

(Average particle size)
The average particle size of the phenolic resin particles is 6 μm or more and 60 μm or less, and preferably 6 μm or more and 15 μm or less. In another aspect of the present invention, as the phenol resin particles, phenol resin particles of 6 μm or more and 15 μm or less and phenol resin particles of 30 μm or more and 60 μm or less may be used in combination. In this case, phenol resin particles having different average particle diameters may be used for the outermost layer and the innermost layer of the two silicone resin layers of the coating layer 4 described above, but as described above, the silicone resin of the outermost layer may be used. It is preferable to use phenol resin particles of 6 μm or more and 15 μm or less for the layer. Here, when phenol resin particles of 6 μm or more and 15 μm or less are used for the outermost silicone resin layer, the friction coefficient of the coating layer 4 becomes larger than when phenol resin particles of 30 μm or more and 60 μm or less are used. ..

In the present invention, the average particle size of the phenol resin particles indicates the biaxial average unfolded diameter. The biaxial average unfolded diameter is the major axis diameter (μm) and minor axis diameter (μm) for any 100 particles, respectively, with a microscope and image analysis software (for example, Keyence Microscope VH-5000 and the same company). It is obtained by measuring with the software VH-H1A5), obtaining a value of (major axis diameter + minor axis diameter) / 2, and averaging the obtained values. The average particle size can be adjusted by a known method such as sieving with a commercially available vibrating sieve.

The phenol resin particles are preferably produced from a conventionally known phenol resin as a thermosetting resin. Here, in the present invention, two or more kinds of phenol resins produced from different kinds of phenol resins may be used in combination as the phenol resin particles.

(Content)
The content of the phenol resin particles in the composition containing the silicone resin is preferably 4% by mass or more and 8% by mass or less, and more preferably 5% by mass or more and 7% by mass or less. When the content of the phenol resin is within the above range, the silicone-coated sponge roller 1 has sufficient wear resistance and a high coefficient of friction.

[Asker C hardness]
The silicone-coated sponge roller 1 of the present invention preferably has an asker C hardness of 40 or more and 75 or less, and more preferably 50 or more and 70 or less. In the present invention, by containing the phenol resin particles in the coating layer 4, the Asker C hardness of the silicone-coated sponge roller 1 becomes higher. As a result, the wear resistance of the silicone-coated sponge roller 1 is improved, and the long-term stain resistance of the silicone-coated sponge roller is guaranteed.

The Asker C hardness conforms to SRIS (Japan Rubber Association standard) 0101 and may be measured using an Asker C hardness tester (manufactured by Polymer Meter Co., Ltd.). More specifically, the hardness measured by abutting the push needle of the Asker C hardness tester on the surface of the silicone-coated sponge roller 1 and applying a constant pressure load (9.8 N) may be defined as the Asker C hardness.

The silicone-coated sponge roller 1 of the present invention has an excellent toner releasability and stain resistance because a coating layer 4 in which a phenol resin powder having a predetermined average particle size is dispersed is formed on the surface thereof. The coefficient of friction with the material to be recorded is large, and the transfer capacity of the material to be recorded is excellent. Further, the silicone-coated sponge roller 1 of the present invention can effectively suppress the wear of the coating layer even when used for a long period of time.

<Image forming device>
In the image forming apparatus of the present invention, the above-mentioned silicone-coated sponge roller 1 is used for the pressurizing / fixing unit. Here, in the image forming apparatus of the present invention, the above-mentioned silicone-coated sponge roller 1 may be used as a pressure roller or a fixing roller. The components other than the pressurizing roller and the fixing roller in the image forming apparatus may be the same as those of known image forming apparatus.

Hereinafter, the present invention will be described in detail with reference to examples. The present invention is not limited to the examples shown below.

<Example 1>
[Preparation of shaft body]
The shaft body (diameter 10 mm × length 250 mm, SUM22) subjected to the electroless nickel plating treatment was washed with toluene and coated with a primer. The primer-treated shaft was fired at a temperature of 180 ° C. for 30 minutes using a gear oven, and then cooled at room temperature for 30 minutes or more to form a primer layer.

[Preparation of foamed silicone rubber composition]
100 parts by mass of a silicone rubber composition containing a vinyl group-containing silicone raw rubber and a silica-based filler, 1 part by mass of an unexpanded microballoon having an average particle diameter of 15 μm, 2 parts by mass of an addition reaction cross-linking agent, and as an addition reaction catalyst. An appropriate amount of the platinum catalyst, 0.5 parts by mass of the reaction control agent, and 2 parts by mass of the organic peroxide cross-linking agent were sufficiently kneaded with two rolls to prepare a foamed silicone rubber composition.

[Preparation of Composition 1 Containing Silicone Resin]
The above except that it does not contain unexpanded microballoons, which are foaming agents, and contains 0.5 parts by mass of phenolic resin particles having an average particle diameter of 8 μm and a sphericality of 0.9 with respect to 10 parts by mass of the silicone rubber composition. A composition containing a silicone resin was prepared in the same manner as the foamed silicone rubber composition of.

[Preparation of Composition 2 Containing Silicone Resin]
The above except that it does not contain unexpanded microballoons, which are foaming agents, and contains 0.5 parts by mass of phenolic resin particles having an average particle diameter of 8 μm and a sphericality of 0.9 with respect to 10 parts by mass of the silicone rubber composition. A composition containing a silicone resin was prepared in the same manner as the foamed silicone rubber composition of.

[Formation of silicone-coated sponge roller]
Next, the shaft body on which the primer layer was formed and the foamed silicone rubber composition were integrally separated by an extrusion molding machine, and the foamed silicone rubber composition was heated at 250 ° C. for 15 minutes using an infrared heating furnace (IR furnace). It was foam-crosslinked. Then, the foamed silicone rubber composition after foaming and cross-linking was secondarily heated at 225 ° C. for 7 hours using a gear oven, left at room temperature for 1 hour or more, and then to an outer diameter of 16.0 mm with a cylindrical grinder. Grinded to form an elastic layer.

Next, the composition 1 containing the silicone resin was applied to the outer peripheral surface of the elastic layer by a roll coater method so that the thickness after curing was 30 μm or more and 60 μm or less, and heat-cured at 150 ° C. for 30 minutes, and then heat-cured. The composition 2 containing the silicone resin was applied by a roll coater method so that the thickness after curing was 30 μm or more and 60 μm or less, and was heat-cured at 150 ° C. for 30 minutes. Finally, it was dried at 200 ° C. for 4 hours to form a coating layer.

<Example 2>
Examples except that the amount of the phenol resin particles added to the composition 1 containing the silicone resin and the composition 2 containing the silicone resin was 1.0 parts by mass with respect to 10 parts by mass of the silicone rubber composition. A silicone-coated sponge roller was produced in the same manner as in 1.

<Example 3>
A silicone-coated sponge roller was produced in the same manner as in Example 1 except that the average particle size of the phenol resin particles added to the composition 2 containing the silicone resin was 50 μm.

<Example 4>
A silicone-coated sponge roller was produced in the same manner as in Example 1 except that the average particle diameter of the phenol resin particles added to the composition 1 containing the silicone resin and the composition 2 containing the silicone resin was 50 μm.

<Example 5>
A silicone-coated sponge roller was produced in the same manner as in Example 1 except that the average particle size of the phenol resin particles added to the composition 1 containing the silicone resin was 50 μm.

<Comparative Example 1>
A silicone-coated sponge roller was produced in the same manner as in Example 1 except that phenol resin particles were not added to the composition 1 containing the silicone resin and the composition 2 containing the silicone resin.

<Comparative Example 2>
A fluororesin tube-coated sponge roller was produced in the same manner as in Comparative Example 1 except that the outer periphery of the elastic layer was covered with a fluororesin tube without applying the composition containing the silicone resin to the outer periphery of the elastic layer.

<Comparative Example 3>
A sponge roller without a coating layer was produced without applying a composition containing a silicone resin to the outer periphery of the elastic layer.

<Evaluation>
[Coefficient of friction]
A silicone-coated sponge roller was set in a reciprocating HEIDO friction coefficient measuring machine, and the friction coefficient with respect to woodfree paper was measured under a constant environment of 20 ° C. and 50% RH. The coefficient of friction is determined by fixing the silicone-coated sponge roller to a special jig and setting it, then setting the high-quality paper on the lower reciprocating table, and placing the silicone-coated sponge roller on the reciprocating table with a load of 290 grams. The reciprocating table was operated at a constant speed for 30 seconds, and the frictional force at that time was read.

[Abrasion outer diameter value]
For the obtained silicone-coated sponge roller, use a polishing mirror film (trade name "MCF40", manufactured by Sankyo Rikagaku Co., Ltd.) with a film-based polishing machine (trade name "Super Finisher SFC050TNd", manufactured by Matsuda Seiki Co., Ltd.). , Film polishing was performed. At this time, the load amount was 500 g, the rotation speed of the spindle was 1000 rpm, and polishing was performed for 1 minute. The outer diameters of the silicone-coated sponge roller before polishing and the silicone-coated sponge roller after polishing were measured, and the difference between the outer diameters was taken as the wear outer diameter value.

[Asker C hardness]
Asker C hardness of the silicone coated sponge roller was measured according to the method described herein.

The above results are shown in Table 1.
Table 1

As is clear from Table 1, by adding phenol resin particles to the composition containing the silicone resin to form a coating layer, the wear resistance characteristics of the silicone-coated sponge roller can be maintained while maintaining the coefficient of friction within a certain range. I was able to make it good. As the phenol resin particles, it was found that the coefficient of friction was better maintained when the phenol resin particles having an average particle diameter of 8 μm were used for the outermost layer of the coating layer.

1 Silicone coated sponge roller 2 Shaft body 3 Elastic layer 4 Coating layer

Claims (5)

It has an elastic layer formed on the outer peripheral surface of the shaft body and a coating layer formed on the outer peripheral surface of the elastic layer.
The coating layer is formed of a cured product of a silicone resin.
Phenol resin particles having an average particle diameter of 6 μm or more and 60 μm or less are dispersed in the coating layer.
A silicone-coated sponge roller having an average cell diameter of 50 μm or more and 150 μm or less of the elastic layer . The silicone-coated sponge roller according to claim 1, wherein the phenol resin particles have an average particle diameter of 6 μm or more and 15 μm or less. The silicone-coated sponge roller according to claim 1 or 2, wherein the coating layer has a thickness of 20 μm or more and 100 μm or less. The coating layer is formed of two silicone resin layers, and phenol resin particles having an average particle diameter of 6 μm or more and 15 μm or less are dispersed in at least the outermost silicone resin layer, according to claim 1. The silicone-coated sponge roller according to any one of 3. An image forming apparatus using the silicone-coated sponge roller according to any one of claims 1 to 4 for a pressurizing / fixing unit.

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