JPH0463862A - Resin composition for roller for holding magnet roll gap of developer - Google Patents

Abstract

PURPOSE:To form an inexpensive resin composition of excellent durability for a roller for holding a gap which is excellent in abrasion resistance, can smoothly roll and does not damage a photoreceptor drum by mixing a polyamide resin with an organic or inorganic reinforcement and a lubricant. CONSTITUTION:45-90wt.% polyamide resin is mixed with 5-35wt.% at least either an organic reinforcement such as aramid fiber or an inorganic reinforcement such as mica or potassium titanate fiber and 5-20wt.% lubricant such as polytetrafluoroethylene or ultrahigh-molecular-weight polyethylene.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a resin composition, and particularly to a roller that maintains a gap between a photosensitive drum and a magnet roll of a developing device of an electronic copying machine (hereinafter referred to as a gap retaining roller). ).

[Prior art and background]

First, the copying mechanism of the electronic copying machine will be explained based on the drawings.

In FIG. 1, reference numeral 1 denotes a paper feed cassette, and the copy paper 2 in this paper feed cassette l reaches the lower surface of the photosensitive drum 6 via a paper feed roller 3 and a transfer roller 4.5.

On the other hand, the light emitted from the light source (not shown) is the original (not shown).
The reflected light reaches the surface of the photoreceptor drum 6. The surface of the photoreceptor drum 6 other than the portion receiving the reflected light is charged to a predetermined potential by the charging charger 7.

Then, the magnet roll 9 is removed by the toner supply roll 8.
Of the toner supplied to the circumferential surface of the photosensitive drum 6, only the charged portion of the circumferential surface of the photosensitive drum 6 attracts the toner, and the toner is transferred onto the copy paper on the lower surface of the photosensitive drum 6. After that, the conveyor 10
The image is then transported to a fixing unit (not shown) and subjected to predetermined processing, completing a series of copies.

As is clear from the above description, the distance between the photoreceptor drum roll and the magnet roll 9 is an important factor that directly affects the clarity of the copied image, so it is required to strictly control it to keep it within a predetermined range. has been done. Gap retaining rollers are used to maintain this gap at a predetermined value. These gap retaining rollers are coaxially fitted with the magnet roll 9 and fitted onto both ends thereof, and while in contact with the photoreceptor drum 6, the gap retaining rollers 9, and in order to fulfill the role of maintaining the gap described above, it is necessary to have the following functions.

That is, regarding the inner peripheral part, [(a) rotate the shaft slightly. (b) Less wear. (C) No load fluctuations due to invading toner. ", and the outer periphery has the following functions: (a) less wear; (b)
) It is necessary to have functions such as "not damaging the other party's photoreceptor drum."

The specific dimensional accuracy required for the gap holding roller is that the inner diameter/outer diameter dimension intersection is 0.01 to 0.03 mm, and the runout accuracy is 0.02 na or less. As shown in FIG. 2, a roller-like roller having a two-layer structure is often used, which has a bearing 12 on the inside and a resin layer 13 made of ultra-high molecular weight polyethylene or polyacetal on the outside.

[Problem to be solved by the invention]

Although the conventional gap holding roller satisfies most of the above-mentioned required functions, it is expensive to manufacture because it has a two-layer structure of an inner hair ring and an outer resin.

The present invention has been made in view of the above-mentioned problems of the conventional technology, and its purpose is to provide excellent wear resistance, smooth rotation, no damage to the photoreceptor drum, and to prevent intruding toner from entering the drum. An object of the present invention is to provide an inexpensive and highly durable resin composition for a gear pump holding roller that is less susceptible to load fluctuations due to

[Means to solve the problem]

In order to achieve the above object, the gist of the present invention is that the polyamide resin is 45 to 90% by weight, and either or both of an organic reinforcing agent such as aramid fiber or an inorganic reinforcing agent such as mica or potassium titanate fiber is used. A resin composition for a magnetorol gap holding roller of a developing device includes 5 to 35% by weight of a lubricant such as polytetrafluoroethylene (hereinafter referred to as PTFE) or ultra-high molecular weight polyethylene.

Polyamide resins include 12 nylon, 6 nylon,
Examples include 46 nylon and 66 nylon.

Calcium sulfate or the like can also be used as the inorganic reinforcing agent.

Lubricants include molybdenum sulfide, tetrafluoroethylene,
Graphite etc. can also be used.

[Effect]

Polyamide resin has a small coefficient of friction and excellent wear resistance.
Moreover, since it has excellent self-lubricating properties, it does not damage the photoreceptor drum and rotates smoothly.

In addition, by incorporating a reinforcing agent within the scope of the present invention,
- Resistant to layer deformation, reduces molding shrinkage and improves dimensional accuracy.

By blending the lubricant within the scope of the present invention, the friction and wear characteristics can be further improved and sliding noise can be reduced.

〔Example〕

Examples and comparative examples of the present invention will be described below.

As shown in Table 1 on page 8, the resin composition according to this example, in which appropriate amounts of reinforcing agent and lubricant were blended with polyamide resin, polyphenylene sulfide resin (hereinafter referred to as PP)
Test pieces of predetermined shapes were prepared for the resin composition of Comparative Example 1 in which glass fiber and PTFE were blended with S and the comparative example 2 of polyacetal resin alone, and the specific gravity (ASTMD792) and tensile strength (ASTMD63
8), bending strength (ASTMD790), bending modulus (
ASTM D 790), coefficient of linear expansion (ASTMD
696), heat distortion temperature (ASTMD648), coefficient of friction, and amount of wear were measured. The results are also listed in Table 1.

The friction coefficient and the amount of wear were measured using a precious wood type friction and wear tester, and the test conditions were a load of 2 kg/cm'', a speed of 20 m/min, a mating material A of 9.5056, and a running time of 48 hours.

In addition, motor load fluctuations were investigated using a precious wood type friction and wear tester under the conditions shown below in the presence of -component toner.

The results are shown in FIG.

The horizontal axis in FIG. 3 shows running time, and the vertical axis shows motor current.

In FIG. 3, curves A, B, C, D, E, and F show the changes in motor current for Examples 1.2.3.4 and Comparative Example 1.2, respectively.

[Motor load fluctuation test conditions]

Load = 1 kg/c+w”, speed -20m/min
, mating material-A15056, running time = 20 hours From Table 1, the following points are clear.

(2) It can be seen that the material according to this example has a smaller friction coefficient and less wear than Comparative Example 1.2, and has excellent friction and wear characteristics.

(2) Although the material according to Comparative Example 1 has high strength and flexural modulus and excellent heat resistance, it has a large coefficient of friction and a large amount of wear, so it is not suitable as a material for gap holding rollers.

(2) The material according to Comparative Example 2 has low strength and flexural modulus because it does not contain any reinforcing material, and has a large coefficient of friction and a large amount of wear because it does not contain a lubricant. Therefore, it cannot be used as a material for gap holding rollers.

As is clear from FIG. 3, in Comparative Example 1.2 (curves E and F), the motor current rapidly increased about 4 to 10 hours after the start of the test, and the motor torque limit was reached, causing the motor to has stopped. However, in all of Examples 1 to 4 (curves A, B, C, and D), the motor current remained stable and the test could be conducted without any problems.

〔Effect of the invention〕

(1) The resin composition according to the present invention has excellent N friction and wear characteristics and self-lubricating properties, so it can be used very suitably as a material for gear pump holding rollers.

(2) Moreover, since the gap retaining roller can be made from a single resin composition, it is possible to reduce costs, and unlike in the case of a two-layer structure, it is necessary to consider the adhesive force between the hair ring and the resin. Nor.

[Brief explanation of the drawing]

Fig. 1 is a partially cutaway perspective view showing an example of the schematic configuration of an electronic copying machine, Fig. 2 is an enlarged sectional view showing the arrangement of the photoreceptor drum, magnet roll, and gap holding roller, and Fig. 3 is a toner-interposed state. FIG. 3 is a diagram showing the transition of motor load current in a friction and wear test. 6... Photosensitive drum, 9... Magnet roll, 11... Gap holding roller

Claims (1)

[Claims] 45 to 90% by weight of polyamide resin, 5 to 35% by weight of either or both of organic reinforcing agents such as aramid fibers or inorganic reinforcing agents such as mica and potassium titanate fibers, and polytetrafluoroethylene, A resin composition for a magnetic roll gap holding roller in a developing device, comprising 5 to 20% by weight of a lubricant such as high molecular weight polyethylene.