JP2784141B2 - Fixing roll - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fixing roll such as a pressure roll or a heating roll in a fixing section of an electrophotographic copying machine or a laser beam printer (hereinafter referred to as LBP).

[0002]

2. Description of the Related Art Conventionally, a polytetrafluoroethylene resin (hereinafter referred to as PTFE) is provided around a metal core in order to improve the releasability of a toner as a heating roll in an electrophotographic copying machine or an LBP fixing unit. ) Or a roll coated with a fluororesin such as PFA described later.

In the case of color copying, a soft heating roll using an elastic silicone rubber for the surface layer of the heating roll is widely used instead of a hard heating roll coated with a fluororesin. The reason why silicone rubber is applied to this heating roll is that, unlike in the case of ordinary black-and-white copying, in fixing a color copy, the surface of the toner fixed on a recording medium such as paper or OHP paper is finished with a high gloss. It is necessary to develop a desired color, and for this purpose, the surface of the heating roll is made a mirror surface, and the silicone rubber, which is the surface layer of the heating roll, deforms and follows the unevenness of the toner, thereby uniformly melting the toner. That's why.

[0004]

However, in order to sufficiently melt the toner, it is necessary to apply a high temperature to the toner. However, when the toner is sufficiently melted, the toner itself, called a hot offset, is broken by heat. Phenomenon occurs. In order to prevent this hot offset, it is necessary to supply silicone oil as a release agent.

However, in the case of a soft heating roll using silicone rubber for the surface layer of the heating roller, the silicone rubber swells with silicone oil, so that the life of the heating roll is short.

In order to solve this problem, Japanese Patent Laid-Open No. Sho 62
Japanese Patent Application Laid-Open No. 191871 proposes a heat-fixing roll in which the surface layer is formed of a fluorine rubber in which a heavy metal such as lead oxide is internally added, and a mercapto-modified silicone oil is closely attached to the outer periphery of the elastic layer. However,
The fixing roll having this configuration has a function as a soft roll due to the toner releasing property and rubber elasticity at the very beginning, but the rubber hardness increases as the number of copies increases, and the glossy finished image quality is reduced. There was a problem that it could not be obtained. Further, the color copy did not always have a sufficient release property.

Therefore, in order to be applied to a color copying machine, Japanese Patent Application Laid-Open No. 3-284780 proposes a roll in which an amino-modified silicone oil is chemically bonded to the surface of a fixing roll made of fluororubber. However, in order to maintain sufficient toner releasability even with a roll having this configuration, a large amount of amino-modified silicone oil must be used as a release agent, and as a result, the silicone oil adheres to the copied recording medium. In particular, this problem is remarkable in OHP paper.

SUMMARY OF THE INVENTION The present invention has been made in view of the above points, and has a good fixing property of toner, a high glossy image quality, and a very high quality black and white image and color image. The purpose is to provide a role.

[0009]

Means for Solving the Problems and Actions The present inventors have intensively studied to achieve the above object, and have found that the above problem can be solved by using a fluororubber having a perfluoroether group in the main chain. The present invention has been completed and the present invention has been completed.

That is, in the fixing roll according to the present invention, at least a surface layer of the elastic layer mainly comprises a perfluoroether group, wherein the outer periphery of the metal core is covered with an elastic layer. It is characterized by being formed of a fluoro rubber having a chain.

The perfluoroether group according to claim 1 has the following formula (1) In the polymerization of hexafluoropropylene epoxide represented
Good body .

Next, the present invention will be described in more detail.

Generally, Krytox GPL (trade name, manufactured by DuPont) is exemplified as an oil having a perfluoroether group in the main chain.

However, this Krytox GPL
Is a completely fluorinated non-functional oil, which has no cross-linking points, cannot be used as an elastic polymer, and cannot be used as a fixing member.

The composition comprising a fluororubber having a perfluoroether group in the main chain, such as hexafluoropropylene epoxide, used in the fixing roll of the present invention is disclosed in JP-A-5-339503. The composition is exemplified.

That is, the composition comprising a fluororubber having a perfluoroether group in the main chain has, as a first component, at least two alkenyl groups bonded to a silicon atom in one molecule, and Having at least one fluorinated substituent selected from the groups represented by the following formulas (2) and (3) bonded to a silicon atom and at least one fluorinated substituent represented by the following formula (4): A composition in which siloxane, an organohydrogenpolysiloxane having at least two hydrogen atoms bonded to silicon atoms in one molecule as a second component, and a platinum group metal-based catalyst as a third component at a predetermined ratio. It is an addition-reaction-type liquid fluororubber.

[0017] However, in the formulas (2) to (4), m is an integer of 1 to 4, and n is 1 to 6.
, J is an integer of 1 to 12, and k is an integer of 1 to 4.

The organopolysiloxane as the first component of the composition comprising a fluororubber having a perfluoroether group in the main chain will be further described.

Examples of the alkenyl group include a vinyl group, an allyl group and a cyclohexyl group.
From a practical point of view, a vinyl group and an allyl group are preferred.

In the organopolysiloxane, the content of the fluorine-containing substituents Rf ¹ and Rf ² is usually 5 mol% or more, especially 10 to 50 mol% of the total organic groups bonded to silicon atoms. It is preferable to set the amount as described above. When the total content of the Rf ¹ and Rf ² is less than 5 mol%, the water permeability of the obtained composition does not sufficiently decrease,
Further, the solvent resistance and the releasability may not be sufficiently exhibited.

Specific examples of the organopolysiloxane of the above formula (2) include those represented by the following formula (5).

[0022] Here, R ¹ may be the same or different, and vinyl,
R ² may be the same or different and may be an alkyl group having 1 to 8 carbon atoms such as methyl, ethyl, propyl and butyl, or an aryl group such as a phenyl group. Rf ¹ and Rf ² are each as defined above. n, w, x, y and z are each 0 ≦
n <≦ 3, w ≧ 0, x ≧ 1, y ≧ 1, z ≧ 0.

Further, among the organopolysiloxanes of the above formula (5), those having both ends terminated by a vinyl group represented by the following formula (6) are particularly useful because of their high practicability.

[0024] Here, R ² , Rf ¹ and Rf ² and w, x, y and z are each as defined above.

The organopolysiloxane of the formula (6) is
For example, an organocyclotrisiloxane having a fluorine-containing substituent represented by the following general formula (7) and the following general formula (8)
By a terminal vinyl group-terminated organopolysiloxane represented by the following general formulas (9) and (10) at an appropriate ratio depending on the purpose, respectively, if necessary, using an acid or alkali as a catalyst. It can be produced by polymerizing by the known equilibration reaction used.

[0026] Wherein R ² and Rf are as defined above, Vi is a vinyl group, and m is an integer of 1 or more.

In the polymerization reaction, a ring-opening polymerization catalyst such as a lithium catalyst or a five-coordinate silicon catalyst represented by the following formula (11) is used as a polymerization catalyst. By treating with an organosilicon compound represented by the following general formula (12), a polymer having a very low content of low molecular siloxane can be produced.

[0028] Incidentally, the organocyclotrisiloxane having a fluorine-containing substituent represented by the formula (7) used in the above-described production method,
For example, it can be synthesized by reacting a disiloxane diol represented by the following general formula (13) with a dichlorosilane represented by the following general formula (14) in the presence of a tertiary amine such as triethylamine. 3-75
No. 58).

[0029] Here, in the formula, R ² and Rf are each as defined above.

Next, the organohydrogenpolysiloxane as the second component of the composition comprising a fluororubber having a perfluoroether group in the main chain will be further described.

The organohydrogenpolysiloxane has at least two hydrogen atoms bonded to a silicon atom in one molecule.
² HSiO unit, HSiO _1.5 unit, (R ² ) ₂ SiO
Unit, R ² SiO _1.5 unit, (R ² ) ₂ HSiO _0.5 unit, (R ² ) ₃ SiO _0.5 unit, R ² RfSiO unit,
Examples of the polymer include RfSiO _1.5 units (where R ² is as defined above, and Rf is Rf ¹ or Rf ² ), and may be any of linear, branched and cyclic polymers. It may be something. Among these, those represented by the following general formula (15) or (16) are practically preferable.

[0032] However, R ³ is a hydrogen atom, an alkyl group having 1 to 8 carbon atoms or a phenyl group, and R ⁴ may be the same or different, and an alkyl group having 1 to 8 carbon atoms, a phenyl group and the above formula ( 2) It is at least one kind selected from the fluorine-containing substituents represented by (3) and (4), and p and q are integers of p ≧ 1 and q ≧ 0, respectively. Here, p is a number such that three or more hydrogen atoms are bonded to a silicon atom in one molecule.

[0033] However, R ⁴ is the same as described above, and Rf ³ is a divalent perfluoroalkylene group or a divalent perfluoropolyether group,
n is an integer of 1 to 3.

As the divalent perfluoroalkylene group or divalent perfluoropolyether group, those of the following formula groups are exemplified.

[0035] The compounding ratio of the first component and the second component in the composition made of the fluororubber having a perfluoroether group in the main chain used in the fixing member of the present invention is such that the silicon component in the first component has A ratio of at least 0.5 hydrogen atoms bonded to silicon atoms in the second component to one bonded alkenyl group, especially alkenyl groups bonded to silicon atoms in the first component to silicon atoms in the second component The ratio of hydrogen atoms bonded to the atoms is 1: 0.5 to 1:10, particularly 1: 1 to 1: 5
It is preferable that the ratio be as follows.

The composition used in the present invention contains a platinum group metal catalyst as a third component in order to cause an addition reaction between the first component and the second component. Examples of the platinum group metal-based catalyst include platinum group metals such as platinum, rhodium, and iridium, and compounds thereof.Preferably, chloroplatinic acid, complex salts of chloroplatinic acid with various olefins, vinylsiloxane, platinum black, What carried out platinum on various supports is illustrated.

The amount of the third component platinum group metal-based catalyst to be added is usually based on the amount used for the curable silicone composition utilizing the main addition reaction, that is, the total weight of the first component and the second component. 1 to 1,000 ppm as platinum
Is preferably within the range.

The composition used in the present invention comprises the above-mentioned first composition.
It can be obtained by blending each component of the third component from the component in a predetermined amount, and various organic nitrogen compounds, organic phosphorus compounds, acetylene compounds, oxime compounds for the purpose of suppressing the activity of the platinum metal catalyst of the third component. If necessary, an activity inhibitor such as an organic chloro compound may be added.

Further, the composition used in the present invention contains a heat shrinkage during curing, a decrease in the coefficient of thermal expansion of the obtained cured elastic body, heat stability, weather resistance, chemical resistance, flame retardancy, Other fillers may be added for the purpose of improving mechanical strength or lowering gas permeability. Examples of the filler include dry silica, wet silica, diatomaceous earth, quartz powder, glass fiber, magnesium silicate, aluminum silicate, clay, talc, mica powder, barium sulfate,
Metal oxides such as aluminum oxide, titanium oxide, cerium oxide, aluminum carbonate, calcium carbonate, etc.
And metal carbonates such as magnesium carbonate. Further, if necessary, an appropriate pigment, dye or antioxidant can be added.

In order to impart thermal conductivity and conductivity, alumina, red iron oxide, zinc oxide, conductive carbon black and the like may be added as needed.

The composition used in the present invention thus obtained is poured into a mold or the like, and cured at room temperature, cured by heating,
By a known technique such as ultraviolet curing, preferably, for example,
It can be cured by heat treatment at 25 ° C. for 24 hours or more or 100 ° C. for 30 seconds or more to form a rubber elastic body.

The composition of the present invention is diluted with an appropriate organic solvent such as chlorofluorocarbon, xylene hexafluoride, perfluorooctane, benzotrifluoride, methyl ethyl ketone, etc., according to the workability at the time of use. Is also good.

As a specific example of the composition used in the present invention thus obtained, SIFEL (trade name, manufactured by Shin-Etsu Chemical Co., Ltd.) is exemplified, and the physical properties of typical grades are shown in Table 1.

[0044] The fact that the composition of the present invention has rubber elasticity unlike conventional fluororesins is due to the difference in the main chain structure.

That is, PFA (copolymer of tetrafluoroethylene and perfluoroalkyl vinyl ether) which is a typical fluororesin having a perfluoroether group
Has a structure represented by the following formula (17), and an ether group (-O-) is attached to a side chain.

[0046] Here, Rf is a perfluoroalkyl group.

On the other hand, in the composition used in the present invention, as apparent from the above formula (1), an ether group is present in the main chain. Thus, when a crosslink point is formed and cured to form a network structure, a polymer having rubber elasticity is obtained. To further explain, the composition used in the present invention has an ether group in the main chain, so that epichlorohydrin rubber or silicone rubber,
It has rubber elasticity like urethane rubber, etc.
It has excellent releasability from toner like FA and the like.

FIG. 1 shows an embodiment of the fixing roll of the present invention.

The fixing roll 1 of this embodiment is formed by providing a rubber layer 3 made of a fluororubber having a perfluoroether group in the main chain on the entire outer periphery of a pipe-shaped metal core 2. ing. Thus, the fluororubber layer 3 having a perfluoroether group in the main chain is formed on the surface layer of the fixing roll 1. This fluoro rubber layer 3 has sufficient elasticity required for color copying,
It has excellent toner releasability.

The fixing roll 1 has a heater 4 inside.
Functions as a built-in heating roll, forms a fixing device with the pressure roll 5, and records the toner 7 on the recording medium 6 when the recording medium 6 passes between the two rolls 1, 5. The image is fixed on the medium 6.

At this time, since the fluororubber layer 3 of this embodiment exerts a fixing effect with sufficient elasticity and releasability from the toner 7, an image of high gloss and extremely high quality is obtained on the recording medium 6. Can be

In this embodiment, the fluororubber layer 3 is formed on the heating roll, but a similar fluororubber layer may be formed on the surface of the pressure roll 5.

Next, a method of manufacturing the fixing roll 1 of the above embodiment will be described.

As this manufacturing method, a conventional manufacturing method can be applied.

For example, the fixing roll 1 may be molded by a LIMS system as a two-liquid addition type.
The fluoro rubber layer 3 may be formed on the outer periphery of the metal core 2 using a roll coater or the like.

The thickness of the fluororubber layer 3 in the present invention is suitably 5 μm to 5 mm. 5μ of this
m or less, pinholes cannot be avoided, and
If it is more than m, the fixing property does not change, so that it is not necessary to thicken it. Particularly, for a color copying machine, high glossiness and high thermal conductivity are required, so that the range is preferably 300 μm to 2 mm.

Further, in the fixing roll 1 of the present invention, since the composition itself has rubber elasticity, it is necessary to form the elastic layer into a two-layer structure for the purpose of lowering the product hardness as in a conventional PFA-coated roll. However, for the purpose of improving thermal conductivity, countermeasures against electrostatic offset, cost reduction, etc.,
An intermediate layer made of silicone rubber, fluorine rubber, sponge rubber or the like may be formed inside the fluorine rubber layer 3.

It should be noted that the present invention is not limited to the above-described embodiment, and can be changed as needed.

[0059]

As described above, since the fixing roll according to the present invention is constituted and functions, the fixing property of the toner is good, high glossy image quality can be obtained, and extremely high quality black and white images and color images can be obtained. An effect is obtained such that an image can be obtained.

[0060]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, specific embodiments of the present invention will be described.

Example 1 A heating roll as shown in FIG.
SIFEL 200 was coated on the surface of an aluminum core metal 2 having an outer diameter of 38 mm as a fluororubber layer 3 with a doctor blade so as to have a thickness of 300 μm, and then heated at 150 ° C. for 1 hour for vulcanization. It was manufactured by secondary vulcanization at 4 ° C. for 4 hours. This fixing roll 1 is transferred to an NP60 of a copying machine.
30 (trade name, manufactured by Canon Inc.), and a solid black image was copied. As a result, a bright image with extremely high gloss was obtained. 75 ° specular gloss of this image (gloss)
Is a digital gloss meter GM based on JIS Z8741.
It was 50% or more as measured by a -26D type (trade name, manufactured by Murakami Color Research Laboratory Co., Ltd.), and it was found that the solid black image had extremely high gloss. After a continuous paper-pass test of 10,000 sheets, the gloss level did not change, and no fixing failure, paper wrinkles, or image bleeding occurred. I understood.

Example 2 A heating roll as shown in FIG.
An appropriate primer is applied to the surface of an aluminum core bar 2 having an outer diameter of 38 mm, and then SIFEL 21 is applied as a fluororubber layer 3.
0 was coated with a doctor blade so as to have a thickness of 50 μm, and then heated at 150 ° C. for 1 hour for vulcanization.
Next, secondary vulcanization was performed at 200 ° C. for 4 hours. The fixing roll 1 is transferred to the NP of the copying machine in the same manner as the first embodiment.
Attach it to the 6030 and copy the solid black image.
An extremely high gloss shiny image was obtained. When the 75 ° specular gloss (gloss) of this image was measured in the same manner as in Example 1, it was 50% or more, and it was found that the solid black image had extremely high gloss. After a continuous paper-pass test of 10,000 sheets, the gloss level did not change, and no fixing failure, paper wrinkles, or image bleeding occurred. I understood.

Comparative Example 1 As a heating roll of Comparative Example 1, a surface of an aluminum core bar having an outer diameter of 38 mm was coated with PFA of 30 μm as a fluororesin.
, And a heating roll was produced in the same manner as in Example 1 except for the above. When a solid black image was copied on the heating roll in the same manner as in Example 1,
A dull image was obtained. When the 75 ° specular gloss of this image was measured in the same manner as in Example 1, it was found to be 10% or less, indicating no gloss at all.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view showing a main part of a fixing device using a fixing roll, which is an embodiment of a fixing member of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Fixing roll 3 Fluororubber layer 5 Pressure roll 7 Toner

Claims (2)

(57) [Claims] 1. A fixing roll in which an elastic layer is coated on the outer periphery of a metal core, wherein at least a surface layer of the elastic layer is formed of fluororubber having a perfluoroether group in a main chain. And fixing roll. 2. The perfluoroether group is represented by the following formula: In the polymerization of hexafluoropropylene epoxide represented
The fixing roll according to claim 1, wherein the fixing roll is a body .