JP2922560B2 - Separation claw for copier - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an extremely reliable separation claw for a copying machine, which is excellent in heat resistance, heat resistance and heat resistance, and is excellent in the shape of the tip (edge) of the separation claw. It is.

[Conventional technology]

In a conventional apparatus such as a dry copying machine, an electrostatic latent image formed on the surface of a photosensitive drum corresponding to a character or a figure is converted into a toner image, and the toner image is supplied from a paper cassette. The toner image is transferred to the paper surface, and the surface is heated and pressed by a heated fixing roller to fix the transferred toner image to the paper surface, so that the toner image and the paper fibers are fused so that they do not easily separate from each other. The mechanism to do it is incorporated. Then, in order to ensure that the copy paper that has passed through the fixing roller is discharged without being wrapped around the roller, a method of scooping up the end of the copy paper using a separation claw while keeping the leading end thereof in close contact with the outer peripheral surface of the roller is adopted. . Therefore, such a separation claw has a small frictional resistance to the outer peripheral surface of the roller, does not damage the surface, has sufficient mechanical strength, particularly high-temperature rigidity, and has sufficient accuracy in the shape of the tip. In addition, characteristics such as not adhering the toner have been required.

In recent years, especially in recent years, digitalization has led to the so-called intelligent copying, which has not only simple copying functions but also unprecedented high-resolution image processing and editing functions, as well as facsimile functions and input / output devices for other OA equipment. Copiers have been developed, and in such multifunctional, complex, and systemized copiers, demands for higher speed, higher reliability, and longer life have been stronger than ever before.
Now, with regard to the separation claw, the heating speed of the fixing roller is often set to a higher temperature due to the high speed, so that even higher heat resistance is required, and as a part of the system, copying is always possible. Because it will be exposed to high temperatures for an extremely long time, it must have excellent thermal fatigue resistance, and be able to properly follow various conditions due to multi-functionality. Because the connection can be considered, in order to demonstrate the separation function more reliably, the excellent nail tip that can guarantee the heat load resistance of the nail tip that can withstand an accident such as a paper jam and the reliable separation function of repetition Shape is required.

Among the various properties required for such a separation claw, many proposals have been made for improving the non-adhesiveness to toner, for example, by forming a film of a fluororesin or a fluorinated polyether polymer on the separation claw. And a method of kneading a non-adhesion improver such as a fluororesin into the material of the separation nail. However, high-temperature stiffness, thermal fatigue resistance, thermal load resistance, thermal shock resistance, non-aggressiveness of the mating roll, etc. are greatly affected by the type of heat-resistant resin or filler used in the separation nail material, and are satisfactory strategies. Is not widely adopted. That is, as the conventionally used separation claw material, polyimide, polyamide imide, polyphenylene sulfide, polyether ketone, polyether sulfone, polyether imide, aromatic polyester and the like can be mentioned. In order to function as a separation nail material at the above high temperature, resins such as ordinary heat-resistant polyethersulfone and polyetherimide have a glass transition point of around 220 ° C. and are amorphous, so If the temperature is higher than the temperature, the resin softens and the heat resistance is too low to satisfy the demand for the improvement in heat resistance accompanying the speeding up of the copying machine. There are also polyether sulfones and polyether imides having a glass transition point of 250 ° C. or higher, but are inferior in lubricity and abrasion resistance, and occasionally cause an increase in the torque of the roller drive unit and poor separation. Even if a coating such as a fluororesin is applied, the sliding contact surface with the roller wears out during long-term use, and the separation claw base material and the roller slide. Therefore, poor lubricity and abrasion resistance of the base material are unsatisfactory in terms of extending the life and improving the reliability. In addition, among polyphenylene sulfide or polyimide resin, a thermosetting polyimide resin that forms a three-dimensional network is fragile, so that glass fibers, potassium titanate fibers, heat-resistant fibers such as carbon fibers, or these. Due to the reinforcing effect based on the addition of inorganic powdered fillers such as mica and talc to the fiber, the heat resistance is greatly improved, but there is a problem of damaging the mating roller and the filling of the claw tip with these reinforcing agents is poor. In addition, there is a problem that the heat deformation resistance is remarkably deteriorated, and a problem that it is difficult to prolong the service life, that is, it becomes brittle when exposed to a high temperature for a long time to be gradually oxidized and crosslinked. Further, the polyamideimide resin has a heat resistance of 250 ° C. or more as a separating claw material without adding a reinforcing agent, but has a disadvantage that the heat resistance is reduced when water is absorbed (or absorbed moisture). When a large amount of water is absorbed, the heat resistance becomes very poor. Specifically, when the molded article is rapidly heated at the time of absorbing water, the moisture inside the molded article becomes high-pressure steam, so that the molded article becomes a certain amount or more, for example, 5 × (1/2).
× (1/8) cubic inch sheet specimen, (1/8) inch thick surface causes a dimensional change of 2.5μm or more, the minimum temperature at which phenomena such as swelling or foaming ( It is well known that the heat shock temperature is remarkably reduced, and there is a problem that a material having heat resistance of about 280 ° C. at the time of absolute drying can be lowered to about 210 ° C. by a large amount of water absorption. Among polyimide resins, there is a polyimide resin made of a polymer having a very large molecular weight called a thermoplastic polyimide, for example, polyimide "Vespel" manufactured by DuPont of the United States. Since molding is not possible, it is excellent in terms of heat resistance, but is not suitable for practical use.

In contrast to these resins, aromatic polyester resins, especially thermotropic liquid crystal polymers that can be melt-molded and show anisotropy when melted, show a liquid crystal-specific orientation, which results in self-reinforcement, Although it improves its own heat-deformation resistance, there is a large variation in the manifestation of self-strengthening due to this orientation, and if this is small, the thermal deformation temperature as a separation nail material is also lowered, resulting in poor reliability and repeated fatigue. Since it is weak, there is a problem that it is inferior in long-term heat load resistance. On the other hand, the polyether ketone resin has a glass transition point of less than 250 ° C. as in the case of the polyphenylene sulfide resin, but is a crystalline resin, and thus has the same heat-resistant fiber or inorganic powder filling as in the case of the polyphenylene sulfide resin. The heat resistance is improved by reinforcing hardening based on the addition of an agent, but unlike polyphenylene sulfide resin, the resin itself has toughness, so the amount of reinforcing agent can be reduced, and the reinforcing effect like potassium titanate fiber However, since it can be reinforced only with fibers having little damage to the mating material, the aggressiveness of the mating roll is low, and there is almost no development of brittleness (fragility) due to oxygen cross-linking property, and the heat aging resistance is excellent. Further, since a phenomenon such as a decrease in thermal shock temperature due to water absorption such as polyamide-imide resin does not occur, as a separation nail material in polyetherketone resin, JP-A-60-257467 and JP-A-61-27575. A fiber reinforced with a potassium titanate fiber as disclosed in the official gazette is used, but it cannot satisfy the requirements for improved reliability and longer life. That is, as described above, the heat aging resistance is excellent, but the glass transition point is 250 ° C. or less, specifically, the temperature is higher than 140 ° C. to 170 ° C., and at a temperature higher than this, the decrease in the elastic modulus is large. By reducing the degree of reduction, the heat-resistant deformation resistance is maintained. On the other hand, since the surface temperature of the fixing roller of a copying machine is generally 150 ° C. or higher, especially in the range of 170 to 250 ° C., there is a problem of nail tip deformation under a high-temperature load, and paper jams and the like are larger than usual. There is a problem of creep deformation when a force is applied to the tip of the claw, that is, heat resistance load resistance.
In addition, since it has been exposed to a temperature higher than the glass transition point for a long period of time, physical properties such as elasticity tend to decrease rapidly,
There is also a problem that the so-called thermal fatigue resistance is not good. Furthermore, the radius of curvature at the tip of the nail is too small as compared with the polyamide-imide resin, resulting in a sharp edge of less than 10 μm.
Even if a 50μm) product is obtained, if the mold makes it easy for sharp edges to appear due to scars, etc., due to the filler, etc., the high-temperature rigidity of the nail tip becomes small, causing thermal deformation, resulting in poor separation. Or the outer peripheral surface of the roller may be damaged.

[Problems to be solved by the invention]

As described above, in the conventional technology, heat deformation resistance, heat aging resistance, heat shock resistance, heat fatigue resistance, heat load resistance, non-attack to the mating roll and high reliability with excellent tip shape, There has been a problem that a separation claw for a copying machine having a long life has not been obtained, and it has been a problem to solve this problem.

[Means for solving the problem]

In order to solve the above problems, in the present invention,
A means for forming a composite material (composition) containing 100 parts by weight of a polyether ketone resin and 20 to 150 parts by weight of aluminum borate fiber as essential components to form a separating claw for a copying machine is employed. The details are described below.

First, the polyether ketone resin used in the present invention has a general formula -CO-Ar ₁ -CO-Ar _2- (wherein, Ar ₁ and Ar ₂ have at least a diaryl ether bond forming a part of a polymer main chain. One of which is an aromatic residue, Ar ₁ and Ar ₂ are covalently bonded to a carbonyl group through an aromatic carbon atom.) Is a polymer which coexists in an amount of less than 50 monomer%, within a range in which the inherent characteristics of the polyetherketone resin are not lost. And
Suitable polyetherketone resins include: And those having a repeating unit such as
These are available, for example, from ICI of the United Kingdom from VICTREX-PEEK or VICTREX (V
ICTREX) -commercially available as PEK. The method for producing polyetherketone is disclosed in, for example, JP-A-54-90296.

Next, aluminum borate fibers used in this invention, among those represented by the general formula _{nAl 2 O 3 · mB 2 O} 3, refers to a single crystal fiber shown particularly in _{9Al 2 O 3 · 2B 2 O} 3. The shape of the fiber is such that the surface roughness of the separation claw molded product is small and smooth, and the preferable range of the radius of curvature of the separation claw tip is 0.
Since an accuracy of 1 mm or less, preferably 0.05 mm or less is required, it is important that the fiber diameter is 6 μm or less.
If such fibers are used, the surface roughness of the molded product is 1 to 3
μm or less, and the radius of curvature of the separation claw is also
It becomes 0.05mm or less. However, if the radius of curvature of the tip of the separation claw is small, it is not sufficient. Even if the edge is too small and a sharp edge (burr) is obtained, and a good radius of curvature is obtained during mold processing, If the curvature becomes very small due to the scar etc. attached to the mold due to the filler etc. and it becomes easy for sharp edges to appear,
The high-temperature stiffness of the tip of the nail becomes low, causing thermal deformation,
There is a risk of damaging the outer peripheral surface of the roller.

On the other hand, a composition in which 20 to 150 parts by weight of aluminum borate fiber is added to 100 parts by weight of a polyether ketone resin solves the above-mentioned disadvantages, and has an appropriate radius of curvature (0.01 to 0.05) over a long period of time. mm) can be obtained.

Further, by adding the aluminum borate fiber, the glass transition point (140 to 170) of the polyetherketone resin is obtained.
C)), and the deformation of the tip of the nail under a high-temperature load, particularly under a high load such as a paper jam, is prevented.

This aluminum borate fiber form has an average fiber diameter of 1.
Those having an average fiber length of 5 to 150 μm, an average fiber length of 5 to 100 μm, and an average fiber length / average fiber diameter (aspect ratio) of 5 to 150 are preferred. Aluminum borate fibers can be used without any treatment, but those treated with a silane-based or titanate-based coupling agent or a binder such as epoxy resin or polyimide resin have improved mechanical properties. Is preferred.

It is preferable to add an adhesiveness improver and a thixotropic agent within a range that does not impair the object of the present invention, and other various fillers may be added. Here, the adhesiveness improver is added to increase the adhesion strength between the coating agent to be coated on the surface of the separation claw molded body and the separation claw molded body for improving the non-adhesion of the separation claw to the toner. For example, a thermosetting resin having at least one group of an epoxy group, a carboxyl group, a hydroxyl group, a phenoxy group, a methylol group, and an amino group is preferable, and specifically, a phenol resin or an epoxy resin. Can be mentioned. The thixotropy-imparting agent, when the composition of the present invention is melted, refers to those that provide a thickening effect at a low shear rate, and specifically include fine powder silica, fine talc, diatomaceous earth, and the like. And
By adding these, the straightness of the tip of the separation claw and the variation of the radius of curvature are further improved. Other fillers include antioxidants, heat stabilizers, ultraviolet absorbers, lubricants, mold release agents, coloring agents, flame retardants, flame retardant assistants, antistatic agents which are added to ordinary resin compositions. Abrasion resistance improver (eg, graphite, carborundum, silica powder, molybdenum disulfide, fluororesin, etc.), tracking resistance improver (eg, silica, graphite, etc.), and other fillers (eg, ,
Glass beads, glass balloons, calcium carbonate, alumina, talc, diatomaceous earth, clay, kaolin, gypsum, calcium sulfite, mica, metal oxides, inorganic pigments, etc.
Substances stable at 300 ° C. or higher).

[Action]

By combining the polyetherketone resin and the magnesium borate fiber, not only the radius of curvature of the tip and the adverse effect on the surface smoothness are prevented, but also in the conventional separation nail, a smooth curve cannot be obtained,
Occasionally, sharp edges (burrs) are formed, or even if a good radius of curvature is obtained during mold processing, corrosive gas coming out of the resin during the long-term use process or a compounded filler, etc. Molding that can maintain the appropriate radius of curvature for a long period of time due to the bad shape of the tip of the separation claw due to scars on the mold, the very small radius of curvature, and the easy appearance of sharp edges By eliminating the drawback that the product could not be obtained, and without impairing the excellent thermal shock resistance and flame retardancy of the polyetherketone resin, by suppressing the remarkable decrease in the elastic modulus at temperatures above the glass transition point, It has the effect of further increasing the heat load resistance and the heat fatigue resistance underneath.

〔Example〕

The raw materials used in Examples and Comparative Examples are collectively shown as follows, and the respective abbreviations are shown in []. The mixing ratios of these raw materials were all expressed in parts by weight.

Polyetherketone resin [PEEK] UK ICI: Victrex PEEK450
P, polyetherketone resin [PEK] manufactured by ICI of the UK: Victrex PEK220
G, Liquid crystal polymer [LCP] Dartco USA: Aromatic polyester resin XYDAR-SR
T300, polyphenylene sulfide resin [PPS] manufactured by Toprene: T-4, aluminum borate whisker [BALW] manufactured by Shikoku Chemicals: Albolex, average fiber diameter 0.5
~ 1.0μm, average fiber length 10 ~ 30μm, potassium titanate whisker [PTW] manufactured by Otsuka Chemical Co .: Teismo D102, fiber diameter 0.1 ~ 0.3μm,
Fiber length 20-30 μm, epoxy silane treated product, glass fiber [GF-6] manufactured by Asahi Fiberglass Co .: chopped strand, fiber diameter 6 μm, fiber length 3 mm, amino silane coupling treated product, graphite [GRP] Nippon Graphite: ACP. Among the above-mentioned raw materials, the liquid crystal polymer [LCP] was used by crushing the pellets to an average particle size of 50 μm using a freezing crusher.

Examples 1 to 5: After the respective raw materials were dry-mixed in advance at the mixing ratios shown in Table 1, the mixture was supplied to a twin-screw extruder (PCM-30, manufactured by Ikegai Iron Works, Ltd.). The mixture was melt-kneaded and granulated at 50 rpm. The obtained pellets were injection-molded under the conditions of a cylinder temperature of 350 ° C, an injection pressure of 800 kg / cm ² , and a mold temperature of 210 ° C. The width was 12.7 mm, the length was 126 mm, and the thickness was
A 3.2 mm plate material and a test piece having the same shape as the separating claw used in the Fuji Xerox Copier Model 2700 were obtained. Among these test pieces, the separated nail piece test pieces prepared for investigating the practical functionality of the damage of the roller were all fluorinated polyether polymers having an isocyanate group at the terminal (manufactured by Italy Montedison: Fomblin Z-DISOC 200
0) was immersed in a Freon 113 solution having a concentration of 2.0% by weight, taken out of the solution, and baked at about 200 ° C. for 2 hours.

The bending strength, the radius of curvature of the tip, the surface smoothness, the thermal fatigue resistance, the thermal load resistance, and the practical functionality of the above test pieces were evaluated. The results obtained are summarized in Table 2.

In addition, each of these evaluation methods is as follows.

1) Flexural strength Based on ASTM-D790.

2) Radius of curvature at the tip Using a projector V-16D manufactured by Nippon Kogaku Co., Ltd., the values are shown in the minimum and maximum ranges of the measured values at n = 100. However, 5
If it is smaller than 1 μm, it cannot be measured with high accuracy.
m.

3) Surface smoothness Using a surface roughness meter (Dektak II type, manufactured by Nihon Vacuum Co.)
The surface roughness of the roller contact portion of the separation claw was measured.

4) Thermal fatigue resistance due to nail shape Using a nail tip thermal deformation tester (schematic diagram shown in Fig. 1), the surface temperature of the heat roller 2 is 250 ° C, and the tip load of the separation nail 1 is 3
Under the conditions of 20 g, contact angle (θ) of 100 °, contact time of 1 minute, 1 hour and 12 hours, the deformation t (see FIG. 2) when the test (n = 10) was performed was measured, and the average value was measured. And expressed.

5) Heat load resistance due to claw shape Roller surface temperature using the same testing machine as heat fatigue resistance
The deformation amount t (see FIG. 2) was measured when the test (n = 10) was performed under the conditions of 250 ° C., a contact angle (θ) of 100 °, a contact time of 1 minute, and a nail tip load of 20 g, 40 g, and 100 g. The average was calculated and expressed.

6) Using a non-aggressive dry copier (Fuji Xerox: 2700)
Attach a test piece of the same shape as the separation claw used for it, pass 99 sheets of B5 size separation paper continuously, 50,000 sheets in total, and measure the degree of scratches on the surface of the fixing roll and a surface roughness meter. Confirm the shape before and after the operation of the sliding part of the separation claw by using the roller. The roller has a wear depth of less than 10 μm (marked with ◎), 10 to 15 μm
(O) and those exceeding 15 μm (△) were evaluated in three grades.

Comparative Examples 1 to 6: Except that each raw material was blended in the proportions shown in Table 3, exactly the same operation as in Example 1 was performed to produce a plate-shaped test piece and further a separation claw. The same characteristics were investigated. Table 4 summarizes the obtained results.

The following can be said from Tables 2 and 4. That is, in Examples 1 to 5, the bending strength is good, and the accuracy of the radius of curvature of the tip and the surface smoothness all show good values.
Also, it has excellent heat fatigue resistance and heat load resistance. On the other hand, even if aluminum borate fiber is used,
Comparative Example 1 with less than 20% is excellent in surface smoothness, but the tip R is too small to cause so-called burrs, which is not preferable, and as a result, damage to the mating roller is also poor. Also,
Poor heat resistance and heat load resistance. Conversely, Comparative Example 2 in which more than 150 parts by weight was added was thought to be due to poor dispersibility of the additive. However, the dispersion of the radius of curvature at the tip was large and the surface smoothness was poor. The nature is also large. Further, in Comparative Examples 3 and 4 in which a liquid crystal polymer, a polyphenylene sulfide resin, and aluminum borate fiber were blended as heat-resistant resins other than the polyetherketone resin used in the present invention, respectively, all were heat-resistant fatigue resistance and heat-resistant load resistance. Although the amount of deformation in a short time and in a low load range is small, the nail tip is greatly deformed in a long time or when the load is large, and the separation claw is not used. Furthermore, even if a polyetherketone resin is used,
In Comparative Example 5 using potassium titanate fiber, which is a fiber other than aluminum borate fiber, the heat resistance and heat load resistance for a long time were poor. In Comparative Example 6 using glass fiber, the radius of curvature from the tip radius of curvature was too small to too large, the dispersion was large, the surface smoothness was poor, and the thermal fatigue resistance and thermal load resistance were not good.

〔effect〕

As described above, the separation claw for a copying machine of the present invention comprising a composition containing a polyether ketone resin and an aluminum borate fiber as essential components provides the flame retardancy and thermal shock inherent to the polyether ketone resin. In addition to heat resistance, it has excellent heat fatigue resistance and heat load resistance, and also has excellent aggressiveness to the counterpart roll and excellent shape retention at the tip, making it extremely reliable, especially in continuous high-temperature use. Ideal for applications that require a long life. Therefore, it is not only a device having a copying function, but also a so-called intelligent copying machine equipped with an unprecedented high-resolution image processing, editing function, facsimile function or input / output device of other OA equipment due to digitization etc. It can be fully utilized. Therefore, it can be said that the significance of the present invention is extremely large.

[Brief description of the drawings]

FIG. 1 is a schematic diagram of a nail tip thermal deformation tester, and FIG. 2 is a diagram showing the amount of nail tip deformation. 1 ... separation claw, 2 ... heat roller, 3 ... load, θ ... contact angle, t ... deformation amount.

Claims (1)

(57) [Claims] 1. A separating claw for a copying machine comprising a composite material comprising 100 parts by weight of a polyether ketone resin and 20 to 150 parts by weight of aluminum borate fiber as essential components.