JPH02247678A - Separation pawl for copying machine - Google Patents

Abstract

PURPOSE:To enhance mechanical strength and to improve moldability and smoothness by forming the pawl of a composition consisting of polyphenylene sulfide resin, heat resistant fiber having a specified mean fiber diameter and heat resistant polysulfone resin as essential component. CONSTITUTION:The pawl is formed of the composition of polyphenylene sulfide resin consisting of 100pts.wt. polyphenylene sulfide resin, 20-200pts.wt. heat resistant fiber whose mean fiber diameter is <=6mum, and 10-90pts.wt. heat resistant polysulfone resin as the essential component. By thus making the mean fiber diameter of the added heat resistant fiber <=6mum, an adverse effect on the radius of curvature and the surface smoothness of a leading edge part is prevented. Furthermore, since the heat resistant polysulfone resin is added, the proper radius of curvature is kept for a long period without ruining the heat resistance or the moldability of the polyphenylene sulfide resin.

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to a separation claw for a copying machine.

[Conventional technology]

In conventional devices such as dry copying machines, an electrostatic latent image formed on the surface of a photosensitive drum corresponding to characters or graphics is converted into a toner image, and then this toner image is supplied from a paper feed cassette. The toner image is then transferred to the paper surface, and in order to fix the transferred toner image on the paper surface, a heated fixing roller heats and presses the surface, fuses the toner image and paper fibers, and prevents them from separating easily. It has a built-in mechanism. In order to ensure that the copy paper that has passed through the fixing roller is ejected without getting wrapped around the roller, a method is adopted in which a separating claw is used to scoop up the edge of the copying machine while keeping its tip in close contact with the outer circumferential surface of the roller. . Therefore, such a separation claw has low frictional resistance against the outer circumferential surface of the roller so as not to damage the surface, has sufficient mechanical strength, especially high temperature rigidity, and has sufficient precision in the shape of its tip. In addition, properties such as non-adhesion of toner have been required.

Especially in recent years, demand has expanded from offices of large companies to offices of small and medium-sized enterprises, and even to ordinary households, and there is a strong desire for smaller sizes and lower prices. It is expected that each part of the fixing unit will also be made smaller and lower in price without losing the characteristics essential to the separation claw as described above.

Many proposals have been made to improve non-adhesiveness to toner, which is one of the essential characteristics of separation claws. Method of forming an ether polymer film on a separation nail (Japanese Patent Application Laid-Open No. 61-236577)
According to this method, by immersing it in a low-viscosity liquid, which is an inexpensive method, it is possible to easily change the size and shape of objects that have complicated shapes due to miniaturization, and because it is a thin film. A non-adhesive coating can be applied without breaking.

However, high-temperature rigidity, damage resistance to the mating roll, precision of the shape of the tip of the claw, etc. are largely affected by the type of heat-resistant resin or filler used in the separation claw material.As separation claw materials, polyimide, Examples include polyamideimide, polyphenylene sulfide, polyetherketone, polyethersulfone, polyetherimide, heat-resistant aromatic polyester, and the like. Polyimide, polyamideimide, polyetherketone, and heat-resistant aromatic polyester exhibit excellent high-temperature rigidity without or with a reinforcing agent, but they are expensive and cannot meet the demand for lower prices. Furthermore, although resins such as polyethersulfone and polyetherimide are relatively inexpensive, they have a glass transition point of around 220°C and are poor quality, so they soften at temperatures above the glass transition point. However, because its heat resistance is too low, it can only be used in limited copying machines where the heating temperature of the fixing roller is low. This method is used only for more limited applications because of the fact that the fixing temperature has become higher as the speed of copying machines has increased in recent years.

On the other hand, polyphenylene sulfide resin is inexpensive and has low melt viscosity, so it can be easily filled into thin walls or complicated areas due to miniaturization. Very advantageous.

Although the glass transition point is low at around 90°C, since it is a crystalline resin, heat-resistant fibers such as glass fiber, potassium titanate fiber, and carbon fiber, or mica,
The heat resistance is significantly improved by the reinforcing effect based on the addition of inorganic powder fillers such as talc. However, if the amount of reinforcing agent filled is large, there are problems such as damaging the mating roll and poor dispersion, which results in uneven filling of the reinforcing agent into the tip of the claw, resulting in a decrease in heat resistance or a change in the shape of the tip. On the other hand, if the amount of reinforcing agent filled is small, the melt viscosity of the polyphenylene sulfide resin is very low, so it is difficult to obtain a smooth radius of curvature at the tip of the separation claw, which sometimes results in a sharp curvature. There is the problem of becoming Etsuji (Paris). Furthermore, depending on the type of reinforcing agent, separation claws using short fibers such as potassium titanate fibers as reinforcing agents have problems in that they are inferior in mechanical strength such as bending strength and impact strength, and are also inferior in rigidity at high temperatures. With glass fiber or carbon fiber, even if there is no problem with the reinforcing effect, the surface roughness when forming the separation claw is large, the radius of curvature of the tip is too large, and a good tip shape cannot be obtained, making it difficult to fix. Not only will the paper not be scooped up smoothly, but the separation direction will also be incorrect.

(Problem to be solved by the invention) As mentioned above, in the conventional technology, high temperature rigidity,
In addition to the excellent mechanical strength such as the impact strength or bending strength of the nail tip, it also has excellent moldability that allows the desired radius of curvature of the nail tip to be easily obtained, and the smoothness of the surface of the molded product. There is a problem in that a separation claw that meets the demand for miniaturization has not been obtained, and it has been a challenge to solve this problem.

[Means to solve the problem]

In order to solve the above problems, the present invention has developed a polyphenylene sulfide resin containing 100 parts by weight of polyphenylene sulfide resin, 20 to 200 parts by weight of heat-resistant fibers with an average fiber diameter of 6 μ or less, and 10 to 90 parts by weight of heat-resistant polysulfone resin. This method employs a separation claw for a copying machine using a sulfide resin composition.

The details will be described below.

First, the polyphenylene sulfide resin of this invention is used as a matrix resin, and despite its low price, it exhibits excellent heat resistance with a heat distortion temperature of 260°C or higher, and a melt viscosity that is higher than that of other engineering resins. It is a preferable resin because it is lower than resins called plastics, so it can be easily molded into complex or thin parts, and it has excellent filling properties with fillers. However, the melt viscosity is too low to be used as a separating claw for copying machines, making it impossible to obtain a smooth radius of curvature at the tip of the separating claw, which sometimes results in sharp edges. Items with high viscosity, specifically those with a melt viscosity of 6000 poise at 300°C (orifice: 1 m in diameter,
2 length, load 10 kg) or more is preferable, and 10
A melt viscosity of 50,000 poise is particularly preferred, and the upper limit of the melt viscosity is not particularly limited as long as melt molding is possible. Boise or less is preferable.

Here, the polyphenylene sulfide resin is disclosed in, for example, Japanese Patent Publication No. 44-27671 and Japanese Patent Publication No. 45-3368.
Reaction of a halogen-substituted aromatic compound with an alkali sulfide as disclosed in Japanese Patent Publication No. 46-27255, condensation of an aromatic compound with sulfur chloride in the presence of a Lewis acid catalyst as disclosed in Japanese Patent Publication No. 46-27255 It is synthesized by a reaction, or a condensation reaction of thiophenols in the presence of an alkali catalyst or a copper salt, etc. as disclosed in U.S. Pat. No. 3,274,165, but a specific method can be arbitrarily selected depending on the purpose. You can. In addition, polyphenylene sulfide resin is an uncrosslinked product that is nearly white immediately after the above-mentioned condensation reaction, etc., and as it is, it has a low molecular weight and low viscosity, so it is suitable for use in extrusion molding, injection molding, etc. First, the molecular weight is increased by heating to below the melting point in air and crosslinking with oxygen, or through a condensation reaction process, and the solvent viscosity is changed to be suitable for extraction molding, injection molding, etc. The melt viscosity of Rydon P-4 (polyphenylene sulfide resin manufactured by Phillips Vetroleum, USA), which is commercially available for melt molding after such treatment, is 1,500 to 5,000 under the above-mentioned conditions.
000 voids, but in order to obtain a polyphenylene sulfide resin with a melt viscosity of 10,000 voids or more, the same treatment may be performed, although not particularly limited. For example, the Rydon P-4 may be further cross-linked with oxygen. Good too. In addition, such high melt viscosity polyphenylene sulfide resin is TXOO9 manufactured by Torblen.
It is commercially available as.

Next, the heat-resistant fiber in this invention refers to the molding temperature of polyphenylene sulfide resin (usually 280 to 350
°C), specifically glass fibers, carbon fibers, graphite fibers, ceramic fibers, rock wool, slag wool, potassium titanate whiskers, silicon carbide whiskers, sapphire whiskers, steel wire Examples include copper wire, stainless steel wire, silicon carbide fiber, and aromatic polyamide fiber. The shape of these fibers is such that the surface roughness of the separated claw molded product is small and smooth, and the radius of curvature of the tip of the separating claw is preferably within O, t++w+, preferably 0.
Since accuracy of 0.05w or less is required, the fiber diameter is 6μ.
It is important that the conditions are as follows.

If such fibers are used, the surface roughness of the molded product will be 1 to 3.
- or less, and the radius of curvature of the separation claw is also 0.
．． 05 ■ or less. Furthermore, considering the rigidity and mechanical strength of the separation claw at high temperatures, the fiber length is 0.05a.
m or more, especially 0.1 w or more.Also, considering the aggressiveness of the mating roller, potassium titanate whiskers with small hardness are preferable, but this alone will result in slightly inferior rigidity and mechanical strength at high temperatures. It is preferable to use together the aforementioned fibers having a fiber diameter of 6 nm or less and a fiber length of 0.1 mm or more, such as glass fiber.

The blending amount of these fibers is 20 to 200 parts by weight per 100 parts by weight of the polyphenylene sulfide resin. This is because if the amount is less than the lower limit, the rigidity and mechanical strength at high temperatures cannot be maintained, and if the amount exceeds the upper limit, the fluidity during molding will be extremely deteriorated.

As already mentioned, separation claws molded from a composition made of polyphenylene sulfide resin and heat-resistant fibers, such as glass fibers, have a large surface roughness and an excessively large radius of curvature at the tip. Molded products reinforced with short fibers such as potassium whiskers have poor rigidity and mechanical strength at high temperatures, but it is best to use fibers with a diameter of 6JNA or less, or fibers with a length of 0.1mm or more. It is possible to deal with each by using them alone or in combination. However, it is not enough just to have a small radius of curvature at the tip of the separation claw. If the curvature becomes very small and sharp edges are likely to appear due to scars on the mold, etc., the high temperature rigidity of the nail tip will decrease, causing thermal deformation or damaging the outer peripheral surface of the roller. There is a risk of

On the other hand, heat-resistant polysulfone resin is added to a mixture of polyphenylene sulfide resin and heat-resistant fiber.
The composition overcomes these drawbacks and makes it possible to obtain a separated nail molded product having a suitable radius of curvature (0.01 mg to 0.05 square meters) over a long period of time. Here, the heat-resistant polysulfone resin is a thermoplastic resin having high heat resistance, such as polyether sulfone and polysulfone, which has a sulfone bond in the main chain of the polymer.

Heat resistance here refers to the surface temperature of the fusing roller of the copier (
It is important that the glass transition point at the endothermic onset point (hereinafter abbreviated as "onset") measured with a differential scanning calorimeter (hereinafter abbreviated as DSC) is essential. is 250°C or higher. As such a heat-resistant polysulfone resin, for example, VICTRI! The amount of heat-resistant polysulfone resin added is 10% of polyphenylene sulfide resin.
It is desirable that the amount is 10 to 90 parts by weight relative to 0 parts by weight. This is because if the amount is less than 10 parts by weight, it will not be possible to obtain a separated claw molded product with an appropriate radius of curvature over a long period of time, and if the amount is more than 90 parts by weight, the compatibility with the polyphenylene sulfide resin will deteriorate. This is because it causes a decrease in mechanical strength, which is undesirable. In addition, in order to further increase the compatibility between polyphenylene sulfide resin and heat-resistant polysulfone resin, a copolymer consisting of a polyphenylene sulfide moiety and a polysulfone moiety, or a aromatic sulfide/sulfone polymer may be added to the polymer molecule. Furthermore, it is preferable to blend an adhesion improver and a thixotropy imparting agent within a range that does not impair the purpose of the present invention, and various other fillers may also be blended. The agent is added to increase the adhesion strength between the coating agent coated on the surface of the separated nail molded object and the separated nail molded object in order to improve non-adhesiveness to toner, and includes, for example, an epoxy group, A thermosetting resin having at least one group selected from a carboxyl group, a hydroxyl group, a phenoxy group, a methylol group, and an amino group is suitable, and specific examples thereof include phenol resins and epoxy resins.

In addition, the thixotropic agent refers to an agent that provides a thickening effect at a low shear rate when the composition of the present invention is melted, and specific examples thereof include finely powdered silica, finely powdered talc, and diatoms. By adding these, the straightness and the variation in the radius of curvature of the tip shape of the separation claw can be further improved. In addition, fillers other than these include antioxidants, heat stabilizers, ultraviolet absorbers, lubricants, mold release agents, colorants, I flame agents, flame retardant aids, and antistatic agents that are added to ordinary resin compositions. In addition to additives, wear resistance improvers (e.g., graphite, carborundum, silica powder, molybdenum disulfide, fluorine resins, etc.), tracking resistance improvers (e.g., silica, graphite, etc.), and other fillers (e.g., Examples include glass peas, glass balloons, calcium carbonate, alumina, talc, diatomaceous earth, clay, kaolin, gypsum, calicylum sulfite, mica, metal oxides, inorganic pigments, and other substances that are stable at temperatures above 300°C.

(Function) By setting the average fiber diameter of the heat-resistant fibers added to increase the rigidity and mechanical strength of the separation claw at high temperatures to 6μ or less, the adverse effect on the radius of curvature and surface smoothness of the tip can be avoided. Furthermore, by adding heat-resistant polysulfone resin, it is possible to prevent smooth curves or sometimes sharp edges (burrs) in separating claws using conventional technology, and even if good curvature is not achieved during mold processing. Even if a radius is obtained, the shape of the tip of the separating claw may deteriorate due to scars on the mold caused by corrosive gases emitted from the resin or fillers that are mixed during long-term use. The radius of curvature becomes very small and sharp edges tend to appear, making it impossible to obtain molded products that can maintain an appropriate radius of curvature over a long period of time. Alternatively, it can be manufactured at a low cost without impairing its excellent moldability, which allows it to be easily molded into complex or thin-walled parts.

〔Example〕

The raw materials used in the Examples and Comparative Examples are collectively shown below, and the respective abbreviations are shown in [ ]. Note that all the formulations of these raw materials are expressed in 1ltfft parts.

■ Polyphenylene sulfide NON (PPS-1
3 (manufactured by Phillips Petroleum, USA: Ryton P-4, melt viscosity 2000 poise), ■ Polyphenylene sulfide resin (PPS-2) (manufactured by Kureha Chemical Industry Co., Ltd.: KPSI214, melt viscosity 2000 poise), ■ Polyphenylene sulfide resin (PPS) -3)(
Heat-resistant polysulfone resin (HTA) (Pictrex, manufactured by ICI, UK) ITA7600G, glass transition point 260'C (DSC method, onset)) ,■
Polyether sulfone resin (PES) (manufactured by ICI UK: Pictrex PE54800P, glass transition point 220°C CD5C method, onset)), ■
Polyamideimide resin (FAI) (Torlon 40 manufactured by Amico, USA)
00T.

Glass transition point 260°C (DSC method, onset)
, ■ Glass fiber (GF-33 (manufactured by Asahi Fiberglass Co., Ltd.: chipped strand, 3 fiber diameters, 3 fiber lengths, aminosilane coupling treated product), ■ Glass fiber (GF-6) (Asahi Fiberglass) Made by Asahi Fiberglass Co., Ltd.: Chopped strand, fiber diameter 6μ, fiber length 3mm, aminosilane coupling treated product), Glass fiber (GF-13) (Made by Asahi Fiberglass Co., Ltd.: chopped strand, fiber diameter 13Q, fiber length 3m, aminosilane cup) Ring treated product), [Phase] Potassium titanate whisker (PTW) (manufactured by Otsuka Chemical Co., Ltd.: Tismo D102, fiber diameter 0.1-0.3μ
m, fiber length 20-30IllII), ■ Carbon fiber (C
F-8) (Manufactured by Toho Rayon Co., Ltd.: Besphite IITA, fiber diameter 7
．． 2μ■, fiber length 6am), among the above resin raw materials, ■heat-resistant polysulfone resin MW (
tlTA) was used by pulverizing pellets to an average particle size of 50×m using a freezing pulverizer.

Examples 1 to 8: After dry-mixing each raw material in the proportions shown in Table 1, it was supplied to a twin-screw melt extruder (P (M-30) manufactured by Munen Tekko Co., Ltd., and the cylinder temperature was 290 to 320'. C. Pelletization was performed by kneading and extrusion at a screw rotation speed of 5 Orpm+.The resulting pellets were heated at a cylinder temperature of 310 to 340.
Injection molded under the conditions of 'C1 injection pressure 800kg/cd and mold temperature 130''C, width 12.7m, length 126mm
, a test piece having a thickness of 3.2 m, a width of 41 m1, a length of 25 a, a thickness of 1, and a separation claw having the same shape as that used in a copying machine 12700 manufactured by Fuji Xerox Co., Ltd. was obtained. Among these test pieces, the separation claw test pieces prepared for practical functionality investigation of separation quality and roller damage were all made of fluorinated polyether polymer with isocyanate groups at the terminals (Italian). After immersing a Freon 113 solution (manufactured by Montageson) in a Freon 113 solution at a concentration of 2.0% by weight, the sample was taken out of the solution and baked at about 200'C for 2 hours.

The above test pieces were evaluated for bending strength, stiffness at high temperatures (retention rate of elastic modulus), radius of curvature of the tip, surface smoothness, and practical functionality. These evaluation methods are as follows.

1) Bending strength Based on ASTM-[1790.

2) Stiffness at high temperatures (retention rate of elastic modulus) Using a Toyo Seiki Seisakusho type dynamic viscoelasticity measuring device,
Using a test piece of II1 m, length 25 m, and thickness IIIl, tensile stress was applied at a frequency of 10 Hz, and the temperature change was evaluated in three stages: those with a temperature change (○ mark) and those exceeding 15 - (Δ mark).

The results obtained from the above tests are summarized in Table 2.

Table 2 Comparative Examples 1 to 7: Example 1 except that each raw material was blended in the proportions shown in Table 3.
A test piece was prepared by performing exactly the same operation as in Example 1 to
The same characteristics as in 8 were investigated.

The results obtained are summarized in Table 4.

The change in tensile modulus was determined at 25°C and 250°C.

3) Radius of curvature at the tip Using projector V-160 manufactured by Nippon Kogaku Co., Ltd., n = 100
The minimum and maximum range of measured values is shown.

However, since it is not possible to accurately measure values smaller than 5, they are marked as 1μ.

4) Surface smoothness surface roughness meter (manufactured by Nippon Shinku Co., Ltd.: Dektak II type)
was used to measure the surface roughness of the roller contact area of the separation claw.

5) Using a practical functional dry copying machine (Model 2700, manufactured by Fuji Xerox Co., Ltd.), a test piece with the same shape as the separating claw used in the machine was attached, and 50,000 sheets of 84-size copy paper were continuously passed through. .

Copying is repeated, and the number of copies and the degree of damage to the mating roller at the time when paper separation failure (jamming) occurs is measured using a surface roughness meter, and the shape of the separation pawl contact area before and after operation f! The wear depth of the roller is less than 5μ (marked with ◎).
The following can be said from Tables 2 and 4 of Tables 3 and 4 of 5-15-.

That is, Examples 1 to 8 have good bending strength, and the tensile modulus at high temperature (rigidity at high temperature), accuracy of tip curvature radius, and surface smoothness all show good values. On the other hand, even if glass fibers with a fiber diameter of 6n are used, the average fiber diameter of the heat-resistant fibers is 6n even if heat-resistant polysulfone resin is used and in Comparative Example 1 where heat-resistant polysulfone resin is not used. Comparative example 6 or 7 using something that exceeds
Although the bending strength, tensile modulus, etc. of the samples shown in Comparative Examples 6 and 7 were as good as those of the examples, the radius of curvature of the tip was too small (too large, resulting in so-called "burr"), which was undesirable. Due to the adverse effects of fibers W1, some have too large a radius of curvature, which is undesirable, and the surface smoothness is also poor.
Comparative example 2 has a glass transition point of 250°C or lower and 220°C.
However, the tensile modulus at high temperatures is extremely poor, and the glass transition point is 25.
Even at temperatures above 0°C, the bending strength and tensile modulus at high temperatures of Comparative Example 3 using polyamideimide resin, which is a resin other than heat-resistant polysulfone, were not so bad, but they were not as bad as those with paris generation. The radius of curvature of the tip varies greatly even when it is almost filled, and the surface smoothness is also poor. This is probably due to the extremely poor compatibility between the base material polyphenylene sulfide resin and polyamideimide resin. Similarly to Comparative Example 3, Comparative Example 4 in which the amount of heat-resistant polysulfone resin added was too large resulted in a decrease in compatibility.
The bending strength decreases, and the dispersion of the radius of curvature at the tip increases, resulting in cases ranging from those with cracks to those with no filling. Also, Comparative Example 5 in which the amount of heat-resistant fiber added is too small.
Because the reinforcement effect is too small, the bending strength is too small.
Some have low rigidity at high temperatures and a small radius of curvature.

In this way, Comparative Examples 1 to 7 have bending strength, rigidity at high temperature,
Since there is no product that satisfies all aspects such as tip radius of curvature and surface smoothness, there is no product that has completed copying of 50,000 sheets without causing separation defects even in terms of practical functions, and Comparative Example 2 Because the separation failure occurred too quickly, in all other comparative examples, the damage to the mating roller was also poor, except for the one in which the roller was less likely to be damaged.

〔effect〕

As described above, the separation claw for a copying machine made of a material containing polyphenylene sulfide resin, heat-resistant fibers with an average fiber diameter of 6 nm or less, and heat-resistant polysulfone resin as essential components has excellent mechanical strength and It has excellent rigidity and does not cause clogging or poor separation direction due to the radius of curvature at the tip of the separation claw being too small or large, and because the surface is smooth, the separation paper will not get caught.
If necessary, by applying a non-adhesive coating such as fluorinated polyether polymer, it is possible to achieve excellent non-adhesive properties while retaining the good separation claw shape, resulting in a film that can withstand long-term continuous use. It is. The significance of this invention is extremely great because it achieves these characteristics at a low cost while maintaining the excellent moldability of polyphenylene sulfide resin.

Claims (1)

[Claims] (1) 100 parts by weight of polyphenylene sulfide resin,
A separating claw for a copying machine, characterized in that it is a molded article of a polyphenylene sulfide resin composition containing 20 to 200 parts by weight of heat-resistant fibers with an average fiber diameter of 6 μm or less and 10 to 90 parts by weight of a heat-resistant polysulfone resin.