JPH08267605A - Fluorine-based seamless functional belt - Google Patents

Abstract

PURPOSE: To obtain a seamless functional belt superior in resistance stability, durability to fixing of a toner, durability to repeated folding, dimensional accuracy, and fire retardancy and suitably used for an electrophotographic copying machine, a printer, and time like. CONSTITUTION: A seamless functional belt is made of a fluororesin composition containing 3-30wt.% carbon black wherein a value obtained by dividing a square root of a value of a specific surface area (m<2> /g) by a value of a primary particle diameter (nm) is 0.3 or more and is controlled to have a volume intrinsic resistivity of two digits in the range of 10<5> -10<14> Ω.cm.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a seamless functional belt used for intermediate transfer or conveyance of electrophotographic copying machines and printers.

[0002]

2. Description of the Related Art OA equipment usually comprises a skeleton section, a data processing unit, and a printing unit. The printing unit comprises a driving system, an optical system, a photosensitive system, a transfer system, a conveying system, a fixing system and the like. ing. Various seamless functional belts are used in these. That is, a conductive seamless belt for a photosensitive photoreceptor substrate, a conductive or insulating seamless belt for charging to charge a photoreceptor before writing an electrostatic latent image, and a photoreceptor after transferring a toner image. Conductive seamless belt for removing the residual potential of, a semi-conductive seamless belt for intermediate transfer used when transferring the toner image on the photoconductor to the paper, and semi-conductive for electrostatically adsorbing and transporting the paper. An insulating seamless belt or the like.

Known seamless function belts are made of rubber, polyester, and fluororesin. The required performance is, of course, within the resistance range suitable for the usage conditions, but in addition to that, durability against toner sticking, durability against repeated bending, dimensional accuracy, flame retardancy, etc. are required. It is said that The rubber material is inferior in durability against toner adhesion, dimensional accuracy and flame retardancy, and the polyester material is inferior in durability against toner adhesion and flame retardancy.
On the other hand, those made of fluororesin are excellent in terms of durability against toner adhesion, durability against repeated bending, dimensional accuracy and flame retardancy.

As a conductive filler for controlling the resistance range of the seamless function belt within the range of use conditions, carbon black is generally used because it has good dispersibility and resistance control is possible in a wide range. There is. However, the seamless function belt containing fluororesin and carbon black as main components, when the resistance range is semi-conductive,
It has been pointed out that electrical durability is insufficient when a high voltage is applied and used, resulting in a lack of electrical durability.

[0005]

SUMMARY OF THE INVENTION An object of the present invention is to provide a seamless functional belt used in electrophotographic copying machines, printers and the like. Particularly, it is an object of the present invention to provide a seamless functional belt made of a semiconductive fluororesin composition using carbon black as a conductive filler. Further, it is an object of the present invention to provide a semi-conductive seamless functional belt made of an excellent fluororesin composition with improved reduction in electric resistance during use.

[0006]

Means for Solving the Problems The present inventors have proposed a semi-conductive seamless functional belt made of a fluororesin composition containing carbon black as a conductive filler, which is used in electrophotographic copying machines and printers. Various studies have been conducted to improve the reduction in electric resistance, and it has been found that the problem can be solved by using carbon black having a performance in a specific range, and the present invention has been accomplished.

That is, the present invention has a specific surface area (m ² / g)
It consists of the square root of the fluororesin composition divided by value containing 0.3 or more of carbon black 3-30% by weight of the primary particle diameter (nm) value, the volume resistivity of 10 ⁵ to
The gist of the present invention is a seamless functional belt that is controlled in a double-digit range in the range of 10 ¹⁴ Ω · cm. Hereinafter, the present invention will be described in detail.

Various fluororesins may be used as the fluororesin used in the present invention. Specifically, tetrafluoroethylene-ethylene copolymer (hereinafter abbreviated as ETFE) and polyvinylidene fluoride (hereinafter abbreviated as PVDF). .), Tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer (hereinafter abbreviated as PFA), polychlorotrifluoroethylene (hereinafter PCT).
Abbreviated as FE. ) Or a chlorofluoroethylene-ethylene copolymer (hereinafter abbreviated as ECTFE) and the like. You may use these individually or in combination of 2 or more types. ETF is highly durable against toner sticking
E and PFA are preferable, and ETFE, PVDF, PCTFE and EC are preferable in that molding can be performed at a relatively low temperature.
TFE is preferred. Therefore, ETFE is particularly preferable from both viewpoints.

The carbon black used in the present invention has a large specific surface area, and the smaller the primary particle size, the smaller the decrease in the volume resistivity tends to be, and the specific surface area (m ² /
If the value obtained by dividing the square root of the value of g) by the value of the primary particle diameter (nm) is 0.3 or more, the decrease in volume resistivity is small,
If it is 0.4 or more, there is almost no decrease in volume resistivity. The change in volume resistivity of the present invention is 1 as in Example 1.
It is determined from the resistance change after applying 00V for 10 seconds and after applying 100V for 1 hour.

The kind of carbon black is not particularly limited as long as it satisfies the characteristics in the above range, and acetylene black, furnace black, ketjen black, thermal black and the like can be used.
These carbon blacks can be used alone or in combination of two or more. The fluororesin composition includes
In addition to the fluororesin and carbon black, other fillers, additives, etc. can be added within the range not impairing the characteristics of the present invention.

In a semi-conductive seamless functional belt made of a fluororesin composition containing carbon black as a conductive filler, a decrease in electric resistance is observed when the volume resistivity is 10 ⁵ to 10 ¹⁴ Ω · cm. It is within the range, and the degree of decrease in electrical resistance is large, 10 ⁶ to 10
It is in the range of ¹³ Ω · cm. The semi-conductive seamless function belt obtained by the present invention has a controlled electric resistance and excellent resistance stability, and has a seamless function for charging of electrophotographic copying machines, printers, etc., for intermediate transfer or for conveyance. It is advantageously provided for use as a belt.

[0012]

EXAMPLES The present invention will be specifically described below with reference to examples, but the present invention is not limited to these examples. The measuring methods are as follows. (Melting point) The melting point of fluororesin is measured by differential scanning calorimetry (DS
It was measured using C).

(Specific surface area) The specific surface area of carbon black used the catalog value. (Primary particle diameter) The catalog value was used for the primary particle diameter of carbon black. (Shape factor) A value obtained by dividing the square root of the value of the specific surface area of carbon black by the primary particle diameter. (Volume resistivity) It was measured using Hiresta and Loresta manufactured by Mitsubishi Chemical Corporation.

(Durability to Toner Fixation) The contact angle of pure water was measured. (Durability against repeated bending) Toyo Seiki Co., Ltd.
Using a MIT Folding Fatigue Testing Machine manufactured, the number of times of bending until breaking was measured. (Dimensional accuracy) The belt was cut open and the circumference was measured. (Flame retardancy) It was evaluated based on UL-94.

(Raw material) The following ETFE or the like was used because it has a relatively large contact angle with pure water and a relatively low melting point. (ETFE) Asahi Glass Co., Ltd. Aflon COP C88
A. Melting point = 260 ° C., pure water contact angle = 98 °. (PVDF) Kainer 760 manufactured by Mitsubishi Chemical Corporation.

Melting point = 170 ° C., pure water contact angle = 90 °. (PFA) Aflon PFA P-66- manufactured by Asahi Glass Co., Ltd.
P. Melting point = 306 ° C., pure water contact angle = 115 °. (PCTFE) NEOFLON CTF manufactured by Daikin Industries, Ltd.
EM-300P. Melting point = 211 ° C., pure water contact angle = 84
°.

(PBT) PBT-128 manufactured by Kanebo Co., Ltd.
Melting point = 225 ° C., pure water contact angle = 74 °. The following carbon black was used. (CB1) Carbon Black XC-7 manufactured by Cablack
2. Primary particle size = 30 nm, specific surface area = 254 m ² /
g, form factor = 0.531.

(CB2) Carbon black EC carbon manufactured by Mitsubishi Chemical Corporation. Primary particle size = 30 nm, specific surface area = 800 m ² / g, shape factor = 0.943. (CB3) Denka Black, a carbon black manufactured by Denki Kagaku. Primary particle size = 40 nm, specific surface area = 61 m ²
/ G, form factor = 0.195.

(CB4) Tokai Carbon Co., Ltd. carbon black Toka Black # 3855. Primary particle size = 2
5 nm, specific surface area = 85 m ² / g, shape factor = 0.36
9. (CB5) Tokai Carbon Co., Ltd. carbon black Toka Black # 3845. Primary particle size = 40 nm, specific surface area = 60 m ² / g, shape factor = 0.194.

(CB6) Carbon black Toka Black # 3800 manufactured by Tokai Carbon Co., Ltd. Primary particle size = 7
0 nm, specific surface area = 30 m ² / g, shape factor = 0.07
8. The resin composition was prepared by kneading each resin and carbon black using a biaxial kneader.

(Composition 1) 14 wt% of CB1 was added to ETFE
%added. (Composition 2) 6 wt% of CB2 was added to ETFE. (Composition 3) 15 wt% of CB3 was added to ETFE. (Composition 4) 14 wt% of CB4 was added to ETFE. (Composition 5) 16 wt% of CB5 was added to ETFE. (Composition 6) 22 wt% of CB6 was added to ETFE. (Composition 7) 13 wt% of CB1 was added to PVDF. (Composition 8) 15 wt% of CB5 was added to PFA. (Composition 9) 15 wt% of CB1 was added to PCTFE. (Composition 10) 16 wt% of CB5 was added to PBT.

Example 1 Composition 1 was extruded from an extruder having an annular die and cut to a constant length to give a peripheral length of 350 mm and a length of 260 m.
A seamless belt having a thickness of m and a thickness of 150 μm was obtained. 100
The volume resistivity (ρv ₀ ) after applying V for 10 seconds is 3.0 × 1.
⁰⁹ Ω · cm (hereinafter abbreviated as 3E09 Ω · cm),
The volume resistivity (ρv ₁ ) after applying 100 V for ₁ hour is 4E.
It was 09 Ω · cm. The pure water contact angle was 98 °, and the bending durability was 80000 times. Circumference is 350
It was ± 0.10 mm, and the flame retardancy was equivalent to VTM0.

Examples 2-5 The results of Table 1 were obtained in the same manner as in Example 1 except that the compositions 2, 4, 7 and 9 were used. Comparative Examples 1 to 5 The results of Table 2 were obtained in the same manner as in Example 1 using the compositions 3, 5, 6, 8 and 10.

Comparative Example 6 A rubber seamless belt obtained by using a rubber composition composed of urethane rubber and carbon black in the same manner as in Example 1 had ρv ₀ of 3E09Ω · cm and ρv ₁ of 4E09Ω.
・ It was cm. The pure water contact angle was 60 °, and the bending durability was 40,000 times. The circumference is 350 ± 1.
It was 5 mm and there was no flame retardancy.

[0025]

[Table 1]

[0026]

[Table 2]

[0027]

INDUSTRIAL APPLICABILITY According to the present invention, it is suitable for use in electrophotographic copying machines and printers having excellent resistance stability, durability against toner sticking, durability against repeated bending, dimensional accuracy and flame retardancy. A seamless functional belt can be provided.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI technical display location C08L 27:12

Claims (2)

[Claims] 1. A fluororesin composition containing 3 to 30% by weight of carbon black whose value obtained by dividing the square root of the value of specific surface area (m ² / g) by the value of primary particle diameter (nm) is 0.3 or more. And a seamless function belt whose volume resistivity is controlled within a range of 10 ⁵ to 10 ¹⁴ Ω · cm within a double digit range. 2. The fluororesin is a tetrafluoroethylene-ethylene copolymer, polyvinylidene fluoride, tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer, polychlorotrifluoroethylene or chlorofluoroethylene-ethylene copolymer. The seamless functional belt according to claim 1.