JPH08129317A - Separation claw for copying machine - Google Patents

Abstract

PURPOSE: To obtain a separation claw for copying machine having injection moldability and excellent wear resistance and improved in resistance to impact and fatigue by forming the claw with the formed body of a specified resin composition. CONSTITUTION: This claw consists of the formed body of a resin composition obtained by mixing 50-80wt.% polyether imide resin having a repeating unit shown by the formula, 10-40wt.% titanium oxide whisker and 2-15wt.% aromatic polyamide resin powder. The polyether imide resin shown by the formula is a thermoplastic resin consisting of a combination of the ether linkage and imide linkage. The average fiber diameter of the titanium oxide whisker is preferably controlled to 0.05-3μm and the average fiber length to 1-100μm. The average grain diameter of the aramid resin powder is preferably controlled to 5-50μm. The zinc oxide whisker having a crystal structure of tetraaxidal radial type with each axis tapered can be used instead of the titanium oxide whisker.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a separating claw for a copying machine.

[0002]

2. Description of the Related Art Generally, in a dry copying machine or the like, an electrostatic latent image formed on the surface of a photosensitive drum corresponding to characters or figures is converted into a toner image, and then the toner image is fed from a paper feed cassette. In order to transfer to the paper surface that is supplied and to fix the transferred toner image on the paper surface, the surface is heated and pressed by the heated fixing roller, and the toner image and the paper fiber are fused and both are easily It has a built-in mechanism to prevent it from separating.

A separating claw is used so that the copy paper passing through such a fixing roller is surely discharged without being wound around the roller, and the end of the copy paper is slidably contacted with the outer peripheral surface of the roller. The method of scooping up is adopted.

Therefore, in such a separating claw for a copying machine, frictional resistance against the outer peripheral surface of the roller is small, the surface is not damaged, sufficient mechanical strength, particularly high temperature rigidity, and the cutting edge or particularly It is required that the tip shape has sufficient accuracy and that the toner is not adhered.

In recent years, as the copying speed increases, it becomes more necessary to set the heating temperature of the fixing roller to a higher temperature, and the separating claws are required to have a heat resistance of 250 ° C. or higher, and sometimes 300 ° C. or higher. Has been done.

Examples of conventional molding materials for separating nails for copying machines used under such conditions include polyamideimide, polysulfone, polyphenylene sulfide, polyether sulfone, polyether ketone, and polyether ether ketone.

Further, a polyetherimide resin is known as an engineering plastic. Since this resin has excellent heat resistance, chemical resistance, flame retardancy, electrical characteristics, rigidity, and moldability, it is commonly used for electrical and electronic parts such as automobile parts or mechanical parts, but it is ductile when used alone. It is poor and fragile, and its self-lubricating property and abrasion resistance are not sufficient as a material for separating claws.

Therefore, usually, a polyetherimide resin is added with a fibrous reinforcing agent such as glass fiber, potassium titanate fiber, carbon fiber or the like to reinforce the brittleness and abrasion resistance and, if necessary, the poly (imide) resin. A solid lubricant such as tetrafluoroethylene was added to reduce the friction coefficient before use.

[0009]

However, in the separating nail for a copying machine, which is made of the above polyetherimide resin, the filling amount of the fibrous reinforcing agent such as potassium titanate fiber in order to sufficiently improve the abrasion resistance. If you increase
There is a problem that the adverse effect that the injection moldability is deteriorated appears.

Further, the separating claw made of the reinforced polyetherimide resin is not yet sufficiently satisfactory in impact resistance under high temperature conditions and fatigue resistance under repeated load, and the separation claws of high temperature in a fixing device are not sufficiently satisfied. There are also problems that "chips" may occur due to repeated collisions with the rollers, or fatigue may occur due to repeated loading, resulting in deformation.

Therefore, an object of the present invention is to solve the above-mentioned problems and to provide a separating claw for a copying machine, which is composed of a composition having a polyetherimide resin as a matrix, and has both injection moldability and excellent abrasion resistance. In addition, the impact resistance and fatigue resistance should be improved.

[0012]

In order to solve the above problems, in the present invention, a polyetherimide resin 50 to 80 having a repeating unit represented by the following chemical formula 2 is used.
The separating claw for a copying machine comprises a molded body of a resin composition containing 10% by weight to 10% by weight of titanium oxide whiskers and 2% to 15% by weight of aromatic polyamide resin powder.

[0013]

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A separating claw for a copying machine, which comprises the resin composition further containing a solid lubricant in the range of 3 to 10% by weight, wherein the solid lubricant and the titanium oxide whiskers are used. And the aromatic polyamide resin powder are 12 to 50% by weight of the total composition, and the blending ratio of the polyetherimide resin is 50 to 88% by weight. It was a nail.

Alternatively, in the first separating claw for a copying machine, instead of the titanium oxide whiskers, 10 to 40 zinc oxide whiskers having a crystal structure of four-axis radial type and each axis taper shape are used.
The separating claw for a copying machine is composed of a molded product of a resin composition containing 100% by weight.

Further, in this case, a solid lubricant is further added to 3
A separating claw for a copying machine, which is composed of a resin composition added in a range of 10 to 10% by weight, wherein the total amount of the solid lubricant, zinc oxide whisker and aromatic polyamide resin powder is 12 to 50% by weight of the total composition. %, And the separating nail for a copying machine is made of a molded product of a resin composition in which the proportion of the polyetherimide resin is 50 to 88% by weight.

Alternatively, the separating claw for a copying machine is formed by forming a fluororesin film on the surface of the separating claw for a copying machine made of any one of the above resin compositions.

The details will be described below. As is clear from the formula, the polyetherimide (hereinafter abbreviated as PEI) resin represented by the formula (2) used in the present invention has an ether bond and an imide bond as essential bond units, and depending on the combination, This is a thermoplastic polymer that can be obtained according to the production method described in JP-B-57-9372. Examples of commercially available products of such PEI include Ultem manufactured by General Electric Company, USA.

The titanium oxide whiskers used in the present invention are
A rutile type white needle crystal represented by the chemical formula TiO ₂ ,
Average fiber diameter 0.05-3 μm, average fiber length 1-100 μ
m is preferable. The reason for this is that if the amount is out of the above-mentioned predetermined range, it is difficult to sufficiently fill the tips of the nails or the molding becomes impossible, which is not preferable. From such a tendency, more preferable titanium oxide whiskers have an average fiber diameter of 0.05 to 0.5 μm and an average fiber length of 1 to 30 μm.

In order to further improve the reinforcing effect of the titanium oxide whiskers, it is preferable to improve the wettability and the bondability between the titanium oxide whiskers and the matrix PEI resin by surface treatment with a coupling agent. . As the coupling agent used in this case,
Examples include silicon-based, titanium-based, aluminum-based, zirconium-based, zirco-aluminum-based, chromium-based, boron-based, phosphorus-based, amino acid-based and the like.

The amount of titanium oxide whiskers incorporated in the PEI resin, which is the matrix, is 10 to 40% by weight based on the total amount of the composition. This is because when the titanium oxide whiskers are in a small amount of less than 10% by weight, a sufficient reinforcing effect cannot be obtained, and in a large amount of more than 40% by weight, the mixing of the materials becomes non-uniform and the fluidity at the time of melting is lowered, and the melt molding is performed. Because it will be difficult.

The zinc oxide whiskers used in the present invention are, as shown in FIGS. 1 (a) and 1 (b), four-axis radial type, and each axis is tapered so that the diameter becomes smaller toward the tip. Examples of commercial products of such zinc oxide whiskers include Panatetra manufactured by Matsushita Amtech Co., Ltd.

It is considered that such a zinc oxide whisker exists in a state of a tapered shaft (FIG. 1 (b)) in which most of the shafts are broken during the kneading and molding of the matrix resin. It is considered that the tapered shaft is hard to come out of the resin when exposed on the sliding surface, and is easily oriented and easily enters the nail tip, that is, it efficiently reinforces the nail tip. In order to efficiently perform such an action, the zinc oxide whiskers have a shaft length of 2 to 50 μm and a shaft diameter of 0.2 to 3 μm.
Are preferred.

Examples of the coupling agent for further improving the reinforcing effect of the zinc oxide whiskers include aminosilane type and epoxysilane type.

The amount of zinc oxide whiskers added to PEI is
It is 10 to 40% by weight of the total composition amount. Because, if the amount of zinc oxide whiskers is less than 10% by weight, the sufficient reinforcing effect cannot be obtained, and if it exceeds 40% by weight, the bulk densities of the PEI and aromatic polyamide resin may be significantly different, and the mixture may be uniformly mixed. Because you can't get a good compound.

The aromatic polyamide resin (hereinafter referred to as aramid resin) powder used in the present invention comprises a resin having a general formula represented by the following chemical formula 3 as a repeating unit,
Among such resins, typical examples of aramid resins having a meta-type molecular structure include Nomex (paper-like) manufactured by DuPont, USA, and Conex manufactured by Teijin Limited, and resins having a para-type molecular structure. Typical examples of these are Kevlar (fibrous) manufactured by DuPont, USA and Technora manufactured by Teijin.

[0027]

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In the present invention, among the above-mentioned aramid resins, powdered or powdered ones are used. In the resin composition containing the fibrous aramid resin,
The fibers oriented on the sliding surface appear like a brush and the sliding mating material is easily damaged, which is not preferable.

And, such an aramid resin powder is
It is preferable to employ one having an average particle diameter of 5 to 50 μm. Because, when the average particle size is smaller than 5 μm, the resin composition cannot obtain sufficient abrasion resistance, and
This is because large particles exceeding μm may damage the sliding partner material. As a commercially available powdery aramid satisfying all of the above conditions, Asahi Kasei Corp .: Aramica A
RP-P (average particle size 20 μm) can be mentioned.

The content of aramid resin powder in the total composition is 2 to 15% by weight. Because, if the amount is less than 2% by weight, sufficient abrasion resistance cannot be imparted to the composition.
This is because if the amount is more than 10% by weight, the melt fluidity is poor and molding becomes difficult.

The solid lubricant used in the present invention can be used without limitation as long as it has heat resistance and can reduce the friction coefficient of the resin composition.
Specific examples include graphite, polytetrafluoroethylene (hereinafter abbreviated as PTFE), molybdenum disulfide, graphite fluoride, lead monoxide, and the like. Of these, particularly preferable is the case where PTFE or graphite or both are used in combination, and the frictional resistance of the separating claw to the outer peripheral surface of the roller becomes very small, and the non-aggressiveness to the roller is also improved.

The mixing ratio of the solid lubricant in the entire composition is 3 to 10% by weight. Because, if the amount is less than 3% by weight, the effect of reducing the frictional resistance and the non-aggressiveness with respect to the outer peripheral surface of the mating roller are not sufficient, and the amount is 10% by weight.
If the amount exceeds the above range, the fluidity of the composition remarkably decreases, and the heat distortion resistance of the obtained molded product also remarkably decreases, which is not preferable in any case.

The total amount of the solid lubricant, aramid resin powder and titanium oxide whisker or zinc oxide whisker is preferably 12 to 50% by weight based on the total composition. This is because if the total amount exceeds 50% by weight of the total composition, a homogeneous composition cannot be obtained, and the melt fluidity of the resin is lost, making molding difficult. If the total amount is less than 12% by weight of the total composition, the composition will not have sufficient reinforcing effect, frictional properties and abrasion resistance.

The mixing means such as PEI, titanium oxide whiskers, zinc oxide whiskers, aramid resin powder and solid lubricant may be supplied individually to a melt mixer, or they may be preliminarily supplied to a Henschel mixer or tumbler mixer. Any method may be used in which the mixture is dry-mixed with a general-purpose mixer such as a ribbon blender and then supplied to the melt mixer, and such a specific method is not limited and adopted.

It should be noted that needle-shaped fiber-based reinforcing materials other than those described above (for example, aluminum borate whiskers, glass fibers, carbon fibers, graphite fibers, ceramic fibers, rock wool, slag wool) are used within the range that does not impair the effects of the present invention. , Potassium titanate whiskers, silicon carbide whiskers, kapphire whiskers, wollastonite, steel wires, copper wires, stainless steel wires, silicon carbide fibers) may be added, and further antioxidants, heat stabilizers, and UV absorption. It goes without saying that agents, lubricants, release agents, colorants, flame retardants, antistatic agents, crystallization accelerators and the like may be added as appropriate.

The materials mixed by the above-mentioned method are heated to a temperature range of 340 to 425 ° C. to be plasticized, and then filled in a mold to be solidified and released, so that the desired separation for a copying machine is achieved. Get nails. Furthermore, by subjecting the separating claws to a predetermined heat treatment, it is possible to obtain a long-life separating claw for a copying machine which is excellent in wear resistance, heat deformation resistance and dimensional stability.

Further, in order to improve the non-tackiness of the surface of the separating claw for a copying machine of the present invention, it is preferable to coat the surface of the molded product with a fluororesin.

The fluororesin which can be used in this case is not particularly limited to a polymer in which a main chain composed of a carbon chain is bonded with fluorine, and examples thereof include polytetrafluoroethylene (PTFE) and tetrafluoroethylene. Ethylene-hexafluoropropylene copolymer (PF
EP), a fluorocarbon resin such as tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer (PFA).

As a paint containing these components, an enamel type dispersed in an organic solvent (organic solvent volatilization type) or a low molecular weight fine powder for powder coating (fusion type)
In the form of As a commercially available fluororesin coating agent, enamel type manufactured by Chukoh Chemical Industry Co., Ltd .:
Lighty SF-301, manufactured by Daikin Industries, Ltd .: Tough coat enamel TCW-8809 BK and the like. As a fusion type, Mitsui Fluoro DuPont: PFA-X
500CL, manufactured by DuPont: Vidax AR and the like. A coating agent of the type to be fused may be added with a reinforcing agent or a lubricant to improve abrasion resistance, and a conductivity imparting agent such as carbon black may be added to prevent the separation nail from being charged with static electricity. it can.

As a method for coating the surface of the resin composition with such a fluororesin, a spray coating method, a dip coating method, an electrostatic coating method, a powder coating method, etc. are applied after a predetermined primer is applied if necessary. Can be adopted.

The film thickness of the fluororesin coating formed is 5-4.
It is preferably 0 μm. This is because a thin film having a thickness of less than 5 μm is inferior in abrasion resistance, and a thick film having a thickness of more than 40 μm is difficult to form a predetermined R shape of the nail tip required for the separating nail.

[0042]

The separating claw for a copying machine according to the present invention has a matrix of a polyetherimide resin having both heat resistance and thermoplasticity, so that it can be melt-molded and the injection moldability is also satisfactory. .

The titanium oxide whiskers reinforce the separating claws to improve heat resistance and wear resistance, and the 4-axis radial zinc oxide whiskers are 40 to 60% at the time of kneading and molding the matrix resin. The thing which is broken and exists in the state of a tapered shaft, and the tapered shaft is
When exposed on the sliding surface, it is difficult to come out of the resin, and is easily oriented and easily enters the nail tip, that is, the nail tip is efficiently reinforced.

The aromatic polyamide resin powder added to the composition supplements the above-mentioned characteristics of improving the wear resistance of the titanium oxide whisker and the zinc oxide whisker, which when exposed on the sliding surface. It ’s easy to leave this surface,
For example, even if it is brought into sliding contact with a soft mating material such as a roller coated with PFA, the mating material is less likely to be damaged and the moldability of the matrix is not impaired.

Therefore, the separating claw is excellent in wear resistance, impact resistance and fatigue resistance of the nail tip portion while satisfying good injection moldability and non-damage of the mating material. . If a solid lubricant is used in combination, a separating claw with better non-adhesiveness can be obtained.

[0046]

EXAMPLES The raw materials used in Examples and Comparative Examples are collectively shown below. The blending ratios of these raw materials are all shown below by weight%.

(1) Polyetherimide resin General Electric Co., Ltd .: Ultem (2) Titanium oxide whisker Ishihara Sangyo Co., Ltd .: FTL-300 (3) Zinc oxide whisker Matsushita Amtec Co .: Panatetra, PH 7.0 (4) Aroma Group polyamide resin powder [aramid powder] Asahi Kasei Corp .: Aramica powder ARP-P, average particle size 20
(5) Potassium titanate whisker Otsuka Chemical Co., Ltd .: TISMO-N, PH 7.0 (6) Phenol resin Kanebo Co., Ltd .: Bell Pearl C-2000 (7) Polytetrafluoroethylene [PTFE] Kitamura Co., Ltd .: KTL 610 (8) Coating Primer Liquid Mitsui Fluoro DuPont: MP-902Al (9) Coating PFA Liquid Mitsui Fluoro DuPont: X500Cl [Examples 1 to 11, Comparative Examples 1 to 6] Table 1 or Table 2 After dry-mixing the respective raw materials in advance in the mixing ratio shown in, the mixture was fed to a twin-screw melt extruder (IKE-30, PCM-30), and
The mixture was kneaded and extruded under the condition of 0 to 400 ° C. to granulate. The obtained pellets were fed to an injection molding machine and the cylinder temperature was adjusted to 36
Injection molding was performed under the conditions of 0 to 400 ° C., injection pressure of 1000 kg / cm ² , and mold temperature of 190 ° C. to obtain a separated claw-shaped molded product. This molded product was subjected to heat treatment at 320 ° C. for 5 hours, further spray-coated with the coating primer solution (8) and then dried, and the PFA coating solution (9) was similarly spray-coated thereon. A test piece was obtained by heating it at 340 ° C. for 30 minutes for fusion coating.

The test pieces obtained were examined for moldability, wear resistance, impact resistance, fatigue resistance, and the amount of filling the tip of the nail, and the results are also shown in Table 1 or Table 2. The measurement and evaluation methods are as follows.

Formability For each of the 50 formed separating claws, its claw tip 1a
The shape (see FIG. 2A) was measured from the side using a projector, and the average radius of curvature R (mm) was determined.

Abrasion resistance As shown in FIGS. 2 (a) and 2 (b), the separation claw 1 is brought into sliding contact with the mating material roller 2, and the sliding condition is a temperature of 196 ± 3.
° C, roller rotation speed 148 rpm, load 20 gf, 35
As 0 hour, the difference (mm) in the distance L ′ from the center of the hole diameter to the tip of the nail before and after the test was measured.

Impact resistance The impact resistance was measured using a high impact tester (a schematic diagram is shown in FIG. 3) of the tip of the blade of the separating claw. That is, the lever (length L = 8
(5 mm) with the separation claw 1 mounted on one end and the other end of the lever rotatably supported, and when this is naturally rotated from the upright state to the horizontal state, the tip of the cutting edge of the separation claw 1 is a roller. 2, load (W) 20gf, contact angle (θ) 1
The collision was performed under the condition of 00 °, and the number of collisions until the separation claw 1 was damaged was measured. The number of collisions is 1
The upper limit was 0 times.

Fatigue resistance was measured using an impact fatigue tester (a schematic diagram is shown in FIG. 4) of the tip of the cutting edge of the separating claw. That is, the separation claw 1 is attached to one end of the lever, the other end of the lever is rotatably supported, and the rotating cam 5 is brought into contact with the lower surface of the lever to intermittently separate the separation claw from the height h = 1 mm. Then, it was allowed to fall naturally and collided with the roller 2. The measurement conditions are as follows: the roller 2 is heated by the heater 4 to a surface temperature of 200 ° C., the load (W) on the tip of the blade of the separation claw 1 is 20 gf, and the contact angle (θ) is 10.
The deformation amount t is 0 ° and the number of collisions is 100,000 (n = 10).
(Μm, see FIG. 5) was averaged.

Amount of filling the tip of the nail The side surface of the tip of the separating nail is mirror-finished using a lapping machine, and the amount of whiskers is observed with a scanning electron microscope (SEM). The evaluation was made in three grades, that is, the circles that are marked and the triangles that are hardly filled.

[0054]

[Table 1]

[0055]

[Table 2]

As is clear from the results shown in Tables 1 and 2, Comparative Examples 3, 4, and 5 in which the compounding amounts of titanium oxide whisker, zinc oxide whisker, or aramid resin powder exceeded the respective predetermined amounts, injection molding was impossible. Met. In addition, Comparative Examples 1 and 2 in which the amount of titanium oxide whiskers or zinc oxide whiskers is less than the predetermined amount, or Comparative Example 6 in which these are not added at all are test results of wear resistance, impact resistance, and fatigue resistance. However, the amount of whisker filling the tip of the nail was small.

On the other hand, Examples 1 to 11 satisfying all the conditions are in all test items such as moldability, wear resistance, impact resistance, fatigue resistance, and the amount of whisker filling the tip of the nail. Excellent results were obtained, and in particular, it was found from the viewpoint of wear resistance that the life was 3 to 4 times that of Comparative Examples 1, 2 or 6.

[0058]

As described above, the present invention uses a polyetherimide resin represented by a predetermined formula as a matrix,
Since it is a separation claw for a copying machine, which is made of a resin composition of a molded product in which a predetermined amount of titanium oxide whisker or zinc oxide whisker of a predetermined shape and aromatic polyamide resin powder are blended, the injection moldability is satisfied, and the tip of the separation claw is good. It is reinforced and has excellent wear resistance, and when it comes into contact with a soft sliding mating material such as a roller coated with PFA, it does not get damaged due to the characteristics of the powdery aromatic polyamide resin,
Moreover, there is an advantage that the impact resistance and the fatigue resistance are also excellent.

When a solid lubricant is used in combination with such a separating nail composition, not only the above-mentioned effects but also non-adhesiveness are excellent, and the surface of a molded product is coated with a fluororesin. It also has the advantage of exhibiting superior sliding characteristics and non-adhesiveness.

[Brief description of drawings]

FIG. 1A is an enlarged perspective view illustrating a crystal structure of a four-axis radial type zinc oxide whisker. FIG. 1B is an enlarged perspective view illustrating a shape of a broken axis of the zinc oxide whisker.

FIG. 2A is a side view of a separating claw for a copying machine used in an abrasion resistance test. FIG. 2B is a schematic side view illustrating a measurement state of the abrasion resistance test.

FIG. 3 is a schematic side view of an impact resistance tester.

FIG. 4 is a schematic side view of a fatigue resistance tester.

FIG. 5 is a side view of a separation claw for a copying machine showing a deformation amount t of a claw tip.

[Explanation of symbols]

 1 Separation Claw 2 Roller 3 Weight 4 Heater 5 Cam R Separation Claw Tip Angle L Lever Length L'Distance θ Contact Angle t Deformation W Load h Impact Height

Claims (5)

[Claims] 1. A polyetherimide resin having a repeating unit represented by the following chemical formula 1 in an amount of 50 to 80% by weight:
Separation claw for a copying machine, comprising a molded product of a resin composition containing 10 to 40% by weight of titanium oxide whiskers and 2 to 15% by weight of aromatic polyamide resin powder. Embedded image 2. A separating pawl for a copying machine, comprising the resin composition according to claim 1 further containing a solid lubricant in a range of 3 to 10% by weight. A copy made of a molded product of a resin composition in which the total amount of titanium oxide whiskers and aromatic polyamide resin powder is 12 to 50% by weight of the total composition, and the mixing ratio of the polyetherimide resin is 50 to 88% by weight. Separation claw for machine. 3. The separating claw for a copying machine according to claim 1, wherein the titanium oxide whisker is replaced by a resin containing 10 to 40% by weight of a zinc oxide whisker having a four-axis radial type and a crystal structure of each axis taper. Separation claw for a copying machine, comprising a molded body of the composition. 4. A separating claw for a copying machine, comprising the resin composition according to claim 3 further containing a solid lubricant in a range of 3 to 10% by weight. A copy made of a molded product of a resin composition in which the total amount of zinc oxide whiskers and aromatic polyamide resin powder is 12 to 50% by weight of the total composition, and the mixing ratio of the polyetherimide resin is 50 to 88% by weight. Separation claw for machine. 5. A separating claw for a copying machine, wherein a fluororesin film is formed on a surface of the separating claw for a copying machine, which is made of the resin composition according to claim 1.