JPH0228675A - Separating claw for copying machine - Google Patents

Abstract

PURPOSE:To obtain a separating claw for a copying machine having high heat resistance and impact strength or bending strength, etc., at a tip end of a claw, providing easily a desirable radius of curvature to the tip end part of the claw and superior smoothness to the surface of the claw prepd. by molding a specified resin compsn. to obtain the claw. CONSTITUTION:A resin compsn. consisting of 25-80wt.% polyphenylene sulfide resin, 10-65wt.% ceramic fibers having <=3mum average fiber diameter, and 10-40wt.% whisker having 0.1-1.0mum average fiber diameter and 5-200mum average fiber length, is molded. Thus, a separating claw for a copying machine having high mechanical strength and high rigidity and causing no clogging of paper nor defect of separation direction due to too small or too large radius of curvature at the tip end of the separating claw, is obtd. Moreover, unsmooth transfer of separated paper is also prevented due to the smooth surface of the claw. The claw is sufficiently durable to continuous use for a long period.

Description

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

[Conventional technology]

Conventionally, copying machines are broadly divided into two types: dry type and wet type. In dry type copying machines, electrostatic latent images formed on the surface of a photosensitive drum corresponding to characters, figures, etc. are converted into toner images. After that, this toner image is transferred to the paper surface supplied from the paper feed cassette, and the surface is heated and pressurized by a heated fixing roller to fix the transferred toner image on the paper surface, and the toner image and It has a built-in mechanism that fuses the paper fibers and prevents them from separating easily.

In order to ensure that the copy paper that has passed the fixing roller is ejected without being wrapped around the roller, a method is adopted in which a separating claw is used to scoop up the edge of the copy paper while keeping its tip in close contact with the outer peripheral surface of the roller.

Therefore, such separation claws must have low frictional resistance against the outer peripheral surface of the roller so as not to damage the surface, have sufficient mechanical strength, especially high temperature rigidity, and have sufficient precision in the shape of the tip. Furthermore, characteristics such as non-adhesion of toner are required.

In order to meet the characteristics essential to such separation claws, glass fibers are added to heat-resistant resins such as polyimide, polyamideimide, polyphenylene sulfide, polyethernitrketone, polysulfone, polyetherimide, aromatic polyamide, and aromatic polyester. , potassium titanate fibers, heat-resistant fibers such as carbon fibers, and even compositions containing fluororesins have been proposed. For example, in resins such as polyphenylene sulfide, polyether ketone, and polyamide, an average fiber length of 5 to 3
071+11, a composition containing a short fiber reinforcing agent (potassium titanate whisker, etc.) with an average fiber diameter of 0.2 to 0.5 μm (Japanese Patent Application Laid-open No. 182071/1983), a heat-resistant resin such as polyether nitrate ketone resin, etc. Compositions in which heat-resistant fibers such as potassium titanate fibers or asbestos fibers or inorganic fillers such as mica and talc are added to plastic polyether aromatic ketone (Japanese Unexamined Patent Publication No. 61-27575), polyimide 1, polyamide )' A composition containing a hard heat-resistant resin such as Imi-F, phenol, etc., an ethylene resin, and in some cases glass (Japanese Patent Laid-Open No. 56-1
No. 32368), a composition consisting of polyetherketone, potassium titanate fiber, and fluororesin (Japanese Patent Application Laid-open No. 1986-
No. 257467), a composition comprising polyetherketone, carbon fiber and fluororesin (Japanese Patent Application Laid-open No. 61 No. 5567)
No. 4) and the like are disclosed. However, separation claws using short fibers such as potassium titanate fibers as a reinforcing agent as described in JP-A-61-1.8207+, JP-A No. 27575, and JP-A No. 257467 have poor bending strength, impact strength, etc. inferior in mechanical strength,
Since the rigidity is poor at high temperatures, the tip of the separation claw may chip or bend due to the resistance of the passing fixing paper, and the separation function is no longer fulfilled.
As in No. 68 and No. 6N-182071, glass powder or glass peas cause the same problem as the short fiber reinforcement ratio mentioned above, and glass fiber or carbon fiber has a problem of surface roughness when forming separation claws. The radius of curvature of the tip becomes large and the radius of curvature becomes 0. ], mm is often exceeded, making it impossible to obtain a good tip shape and not only making it impossible to smoothly feed the fixing paper V'1, but also causing a phenomenon in which the separation direction is incorrect, resulting in 7. .

(Problems to be Solved and Attempted by the Invention) As described above, in the conventional technology, heat resistance that does not cause a decrease in rigidity at high temperatures, excellent mechanical strength such as impact strength or bending strength of the nail tip, and A score of 8 indicates that no separation claw has been obtained that has excellent moldability and smoothness of the surface of the molded product so that a desirable radius of curvature can be easily obtained.
The challenge was to solve this problem.

[Means to solve the problem]

In order to solve the above problems, this invention uses 25 to 80% by weight of polyphenylene sulfide resin and an average fiber diameter of 3.
10 to 65% by weight of ceramic fibers of p■ or less, and further an average fiber diameter of 0.1 to 1.0-1 and an average fiber length of 5 to 200.
A method is employed in which a separation claw for a copying machine is made of a resin composition comprising 10 to 40% by weight of a .mu.m voice car.

The details will be described below.

First, the polyphenylene sulfide resin of this invention is used as a matrix resin, and exhibits excellent heat resistance with a heat distortion temperature of 260°C or higher, and has a melt viscosity that is higher than that of other resins called engineering plastics. Although this resin is preferred because it has low melt viscosity and excellent moldability and filler filling properties, the melt viscosity is too low to be used as a separating claw for copying machines, so the radius of curvature at the tip of the separating claw is too smooth. It is preferable to use a material with a high melt viscosity; specifically, the melt viscosity at 300°C is 6000 voids (orifice: 1 m in diameter, 2 mm in length). , load 10 kg) or more is preferable, and 10
A melt viscosity of 0.000 poise is particularly preferred, and the upper limit of the melt viscosity is not particularly limited as long as melt molding is possible. The following are preferred.

Here, the polyphenylene sulfide resin is disclosed in, for example, Japanese Patent Publication No. 44-27671 and Japanese Patent Publication No. 45-3368.
The reaction of a halogen-substituted aromatic compound with an alkali sulfide as disclosed in Japanese Patent Publication No. 4627255, the condensation reaction of an aromatic compound with sulfur chloride in the coexistence of a Lewis acid catalyst, as disclosed in Japanese Patent Publication No. 4627255, or U.S. Patent No. 3
It is synthesized by a condensation reaction of thiophenols in the coexistence of an alkali catalyst or a copper salt as disclosed in No. 274165, but a specific method can be arbitrarily selected depending on the purpose. In addition, polyphenylene sulfide resin is an uncrosslinked product that is almost 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 used for extrusion molding, injection molding, etc. Above the melting point in air,
The molecular weight is increased through oxidative crosslinking or condensation reaction, and the solvent viscosity is changed to be suitable for extraction molding, injection molding, injection molding, etc. The melt viscosity of Rydon P-4 (manufactured by Phillips Petroleum), which is commercially available for melt molding after such treatment, is 1,500 to 5,000 boids under the above-mentioned conditions, but it is 1,000
Although there is no particular limitation to obtaining a polyphenylene sulfide resin having a melt viscosity of 0 poise or more, it can be achieved by performing a similar treatment, for example, P-4.
may be further crosslinked with oxygen. Further, such a high melt viscosity polyphenylene sulfide resin is commercially available as TXOO9 from Toblen.

The reason why the blending amount of polyphenylene sulfide resin is set to 25 to 80% by weight is that if the amount is less than 25% by weight, the moldability will be extremely poor, and if the amount is more than 80% by weight, the reinforcing agent will be reduced and the practical strength will be reduced. Therefore, it becomes impossible to put it into practical use. It is from.

Next, the ceramic fibers used in this invention are classified into glass fibers (glass fibers), ceramic fibers, rock wool, slag wool, etc. depending on the raw material. From this point of view, glass fiber is preferable.

General-purpose molding materials containing polyphenylene sulfide resin mixed with 40% or 60% by weight of glass fibers with an average fiber diameter of 13 μm are already on the market, but when the surface roughness of these molded products is measured, it is 5 to 10 u+m (R
On the other hand, the radius of curvature of the tip of the separating claw is 0.11111 or less, preferably 0.05 m.
Since precision of less than m is required, it is difficult to obtain such precision with glass fibers as described above.
It is important that the diameter of the glass fibers to be blended is 6n or less, and if such fibers are used, the surface roughness of the molded product will be 1 to 3μ or less, and the radius of curvature of the separating claws will be 0. 05m+w or less. However, it is not enough just to have a small radius of curvature. If the curvature becomes very small due to scars on the mold and sharp edges are likely to appear, 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 that the radius of curvature (0,
In order to obtain a tip with a diameter of 0.01 mm - 0.05 au*), ceramics award fibers of 3 or less, especially 3
It has been discovered that high high temperature stiffness can be achieved while maintaining high temperature stiffness by blending glass fibers with a diameter of less than m or less with a specific voice car as described below. In addition, considering the rigidity and mechanical strength of the separating claw at high temperatures, the fiber length of the ceramic fiber must be 0.05 m or more, preferably 0.1 mm or more, and the blending amount must also be 10 mm or more. It is desirable that the amount is more than 65% by weight, but if the amount exceeds 65% by weight, the fluidity during molding will be extremely deteriorated, so it is not preferable.

Furthermore, whiskers in this invention specifically include potassium titanate whiskers, silicon carbide whiskers,
Examples include silicon nitride whiskers, among which the average fiber diameter is 0.1 to 1.0 μm and the average fiber length is 5 to 200 μm.
By adding these micrometer voice cars and combining them with the above-mentioned specific ceramic fibers, the radius of curvature of the tip of the nail is neither too small nor too large, and the variation is small, making it possible to reliably use it as a separation nail for copying paper. You can scoop up the edge. If the average fiber diameter is less than 0.1 μm or the average fiber length is less than 5111, the reinforcing property is almost lost, which adversely affects the high temperature stiffness. is 200
For those exceeding μ, there are many cases in which the radius of curvature of the tip of the separation claw described above is too small, and the variation becomes large. Among these various voice cars, potassium titanate whiskers are preferred because they are less aggressive to the mating roller. The filling amount of voice cars is 10 to 40% by weight, but if the amount is less than 10% by weight, it is not possible to obtain a separating claw tip with an appropriate radius of curvature.
This is because if the amount exceeds 1.5%, the amount of ceraminox fibers filled will be reduced accordingly, resulting in a decrease in mechanical strength, especially impact strength.

In addition, it is preferable that each of the polyphenylene sulfide resin, ceramic fiber, and whisker be blended with an adhesion improver and a thixotropy imparting agent within the above-mentioned limited blending ratio, and various other fillers. may be blended. Here, the adhesion improver is added to increase the adhesion strength with the coating agent coated on the separation nail molded product in order to improve the non-adhesiveness of the separation nail to toner. Thermosetting resins having at least one group selected from epoxy groups, carboxyl groups, hydroxyl groups, phenoxy groups, methylol groups, and amino groups are preferred, and specific examples include phenol resins and epoxy resins. In addition, the thixotropic property-imparting 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 fine silica, fine talc, diatomaceous powder, etc. By adding these, the dispersion of the straightness and radius of curvature of the tip shape of the separating claw becomes even better. Furthermore, other fillers include powders of heat-resistant polymer materials such as polyamide-imide resin, polyetherimide resin, aromatic polyester resin, polyimide resin, silicone resin, and fluorine resin, short fibers such as wollastonite and asbestos, Metals such as zinc, aluminum, magnesium or their oxides, graphite, carbon,
Glass peas, silica balloons, shirasu balloons, inorganic powders such as mica, carbon fluff, iron oxide,
Examples include pigments such as titanium oxide, heat stabilizers, and the like.

The mixing means for each of the above raw materials can be either supplied individually to a melt mixer, or dry-mixed in advance with a general-purpose mixer such as a Henschel mixer, tumbler mixer, or ribbon blender, and then mixed in a melt mixer. The specific method is not particularly limited.

The molded article of the above composition may be coated with a coating material in order to increase its non-adhesion to toner or its sliding characteristics with a mating roller. Here, the coating material includes a binder resin with good heat resistance such as epoxy resin, polyimide resin, or polyimide resin, and tetrafluoroethylene resin, tetrafluoroethylene/hexafluoropropylene copolymer resin, or perfluoroalkoxy resin. Fluorine-containing polymers with fluororesins and other additives dispersed in polar solvents,
Alternatively, examples include fluorinated polyether polymers. Among these, since it is a thin film with a thickness of about 1 μm, it maintains a good radius of curvature of the separating claw obtained by molding, and even though it is thin, the film does not peel off and has excellent sliding properties. Fluorinated polyether polymers that can maintain non-adhesive properties for a long period of time are preferred, and the application of this fluorinated polyether polymer to separating nails has already been described in JP-A-60-78699. .

[Function] Ceramic fibers with an average fiber diameter of 3 pra or less are effective in increasing the rigidity and mechanical strength at high temperatures required for separation claws without impairing the radius of curvature and smoothness of the tip. , furthermore, the average fiber diameter is 0.1 to 1-0
By combining the synergistic effect with a voice car with an average fiber length of 5 to 200 μm and selecting a polyphenylene sulfide resin with a high melt viscosity as the matrix, a smooth curve can be obtained in the separating claws according to the conventional technology. Sometimes sharp edges (Paris)
Even if a good radius of curvature is obtained during mold processing, corrosive gases emitted from the resin or fillers that are compounded may cause scratches on the mold during long-term use. However, the tip shape of the separating claw deteriorated, the radius of curvature became very small, and sharp edges tended to appear, making it impossible to obtain a molded product that could maintain an appropriate radius of curvature over a long period of time. Shows a dispelling effect.

〔Example〕

The raw materials used in the Examples and Comparative Examples are shown below, and the respective abbreviations are shown in parentheses.The proportions of these raw materials are all expressed in weight%.

■ Polyphenylene sulfide resin (PPS-M) (
Made by Phillips Petroleum International, USA: Ryton P-4, melt viscosity 2000 poise), ■ Polyphenylene sulfide resin (PPS-M) (
Manufactured by Tope L/7: TXOO9, melt viscosity 13000
Glass fiber (GF-3) (manufactured by Asahi Fiberglass Co., Ltd.: chopped strand, fiber diameter 3μ, fiber length 3M)
, aminosilane coupling treated product), ■ Glass fiber (GF-'6) (manufactured by the same company: chopped strand, fiber diameter 6-1, fiber length 311 m, aminosilane coupling treated product), ■ Glass fiber (GF-13) ) (manufactured by the same company: chopped strand, fiber diameter 13-1 fiber length 3 mm, aminosilane coupling treated product), ■ Ceramic fiber (CELF) (manufactured by IBIDEN: Ibi Wool CP (fiber diameter 2 μm)), ■ Titanic acid Potassium Voice Car [PTW] (manufactured by Otsuka Chemical Co., Ltd.: Teismo DIOI (fiber diameter 0.1 to 0.3μ),
Fiber length 20-30 μm]), ■ Potassium titanate fiber (PTF) (manufactured by Kubota Tekko Co., Ltd.: Potassium titanate fiber type A, fiber diameter 10-30 μm)
30-1 fiber length 80-350 pea), ■ Silicon carbide whisker (SIC) (manufactured by Tokai Carbon Co., Ltd.: Toka Whisker, diameter 0.1-1.0 μ, length 50-20
0 μIm), Examples 1 to 8: After dry mixing in advance at the blending ratio as shown in Table 1 below,
It is supplied to a twin-screw melt extruder (manufactured by Ikegai Iron Works: PCM-30), and the cylinder temperature is 290°C and the screw rotation speed is 5.
The mixture was kneaded and extruded at 0 rpm to form granules. The obtained pellets were heated at a cylinder temperature of 315°C and an injection pressure of 800 k.
Injection molded under conditions of g/cd, mold temperature 130°C, width 12.7 mm, length 126 mm, thickness 3.2 mm, width 4-1 length 25 mm, thickness. A test piece having the same shape as a separation claw used in a NP2O15 copier manufactured by Canon Co., Ltd. was obtained. Among these test pieces, all separation nail test pieces prepared for practical functionality investigations such as quality of separation, presence of nail marks, and damage to rollers were made using fluorinated polyether polymer with isocyanate groups at the ends. Combine (
Made by Montegisson, Italy: Phone Prin Z-DISOC2
Freon 113 (000) dissolved at a concentration of 2.0% by weight
After immersing in the solution, take it out and heat it at about 200°C for 2 hours.
Time-burning treatment was applied.

The above test specimens were evaluated for impact strength, bending strength, stiffness at high temperatures (retention rate of elastic modulus), radius of curvature of the tip, surface smoothness, and practical functionality. That's right.

■) Impact strength: Notched Izot impact strength based on ASTM-0256.

2) Bending strength: Based on ASTM-0790.

3) Stiffness at high temperatures (retention rate of elastic modulus) Using a Toyo Seiki Seisakusho type dynamic viscoelasticity measurement device, the width was 4nu and the length was 25mm.
Using a test piece with a diameter of 1 rm and a thickness of 1 rm, tensile stress was applied at a frequency of 10 Hz, and changes in tensile modulus with respect to temperature changes were determined at 25°C and 260°C.

4) Radius of curvature of the tip: A projector V-16D manufactured by Nippon Kogaku Co., Ltd. was used, and the range is shown as the minimum and maximum range of the measured value at n-10.

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

6) Practical functionality: A dry copying machine (manufactured by Canon Corporation: NP2O15 model) was used to continuously pass 100,000 sheets of A4 size copy paper by attaching a test piece with the same shape as the separation claw used in the machine. I made paper.

After repeated copying, the number of copies made at the time when paper separation failure (paper jam) occurred, whether or not toner image contamination due to fingernail marks occurred,
We checked the damage of the mating roller, that is, the shape of the contact part of the separation pawl before and after operation using a surface roughness meter. It was evaluated in three stages: (marked) and those exceeding 15 μm (Δ).

The results obtained from the above tests are summarized in Table 1.

Comparative Examples 1 to 5: Completely the same as Example 1 except that the various raw materials were blended in the proportions shown in Table 2 (by performing the mixing process, cylindrical and plate-shaped molded bodies and separation claws were produced). The same properties as those in Example 1-8 were investigated.The obtained results are summarized in Table 2.

The following is clear from Tables 1 and 2 in the margin below. That is, Examples 1 to 8 have good impact strength and bending strength, and exhibit good values for tensile modulus at high temperature (rigidity at high temperature), accuracy of tip curvature radius, and surface smoothness. On the other hand, in Comparative Example 1, which uses glass fibers with a diameter of 3 [diameter 3] but does not use whiskers, the impact strength, bending strength, tensile modulus, etc. show good values equivalent to those of the example, but the tip The radius of curvature became too small, causing so-called paris, which was undesirable. In addition, Comparative Example 2 did not contain ceramic fibers, and with only potassium titanate whiskers, the fiber length was too short to produce a reinforcing effect, and both mechanical strength and tensile modulus at high temperatures were poor. Comparative Examples 3 and 4 using glass fibers with a large fiber diameter have good mechanical strength and tensile modulus at high temperatures, but Comparative Example 3 using glass fibers with a diameter of 1.6 μm still has poor tip curvature. Comparative Example 4 using glass fibers of 13 μm has a small radius that sometimes appears and causes so-called “paris”.
The dispersion in the radius of curvature of the tip was large, and the surface smoothness was also poor. Moreover, even if the same potassium titanate is used, Example 3
is a whisker with small fiber diameter and fiber length, while Comparative Example 5, which contains large fibers,
The tip radius of curvature has become too small. Next, regarding practical functionality, in Examples 1 to 8, 100,000 copies were completed without causing any separation failure, but in Comparative Examples 1 to 5,
All of them caused clogging during the process, claw marks were found in Comparative Examples 1 and 4, and Comparative Examples 1, 4, and 5 were not good in terms of damage to the mating roller.

〔effect〕

As described above, the polyphenylene sulfide resin of the present invention, ceramic fibers having an average fiber diameter of 3 or less, an average fiber diameter of 0.1 to 1.0μ, and an average fiber length of 5 to 200
The separation claw for copying machines, which consists of a μl voice car, has excellent mechanical strength and rigidity at high temperatures, 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. In addition, since the surface is smooth, the separation paper will not get caught, and if necessary, by applying a non-adhesive coating such as fluorinated polyether polymer, the separation paper will maintain its excellent non-adhesive shape. As a result, it can withstand long-term continuous use. Therefore, it can be said that the significance of this invention is extremely large.

Claims (1)

[Claims] (1) 25 to 80% by weight of polyphenylene sulfide resin and 10 to 10% of ceramic fibers with an average fiber diameter of 3 μm or less
65% by weight and further an average fiber diameter of 0.1 to 1.0 μm,
A separating claw for a copying machine, characterized in that it is a molded article of a resin composition comprising 10 to 40% by weight of whiskers having an average fiber length of 5 to 200 μm.