JP3318943B2 - Seamless belt - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a seamless belt for a photoreceptor substrate, a seamless belt for intermediate transfer, a seamless belt for conveyance, a seamless belt for fixing, and a seamless belt for development used in electrophotographic copying machines, laser printers and the like. The present invention relates to a highly durable conductive seamless belt provided with flame retardancy, which is used for the like.

[0002]

2. Description of the Related Art Conventionally, a conductive seamless belt has been frequently used in an intermediate transfer device, a transfer separation device, a charging device and the like of an electrophotographic copying machine and the like. FIG. 1 is a plan view of the intermediate transfer device. In the figure, 1 is a photosensitive drum, and 6 is a conductive seamless belt. An electrophotographic process unit including a charging device 2, an exposure optical system 3 using a semiconductor laser or the like as a light source, a developing device 4 containing toner, and a cleaner 5 for removing residual toner. Is arranged.

[0003] The conductive seamless belt 6 is stretched over conveying rollers 7, 8, 9 and is moved in the direction of the arrow in synchronization with the photosensitive drum rotating in the direction of the arrow. Regarding this operation, first, the surface of the photosensitive drum 1 rotating in the direction of the arrow is uniformly charged by the charger 2. Next, an electrostatic latent image is formed thereon by the optical system 3, and the latent image is developed by the developing device 4. The toner image formed by this development is electrostatically transferred to the conductive seamless belt 6 by the electrostatic transfer device 10.

[0004] The toner image transferred onto the belt is conveyed by conveying rollers 7, 8 and 9, and is transferred to recording paper 11 between conveying roller 9 and pressing roller 12. By the way, electrophotographic copying machines and the like and conductive seamless belts correspond to electrical equipment and plastic materials defined by the UL standards of the United States, and therefore must fully comply with these regulations.

A conventional conductive seamless belt made of a thermoplastic resin is made of a material in which conductive particles such as flammable carbon black are added to a thermoplastic resin. Sex is significantly reduced. Therefore, in order to improve the flame retardancy, various flame retardants were added and examined.The flame-retardant conductive seamless belt composed of the resin to which the flame retardant was added was a conductive seamless belt without the addition of flame retardant. In operation, compared to a belt,
It was found that cracks were easily generated and the durability was extremely poor.

[0006]

SUMMARY OF THE INVENTION An object of the present invention is to provide a conductive seamless belt having excellent durability.

According to the present invention, as a result of diligent studies to solve the conventional problems, a resin layer containing a substance which deteriorates durability and a conductive agent, and a material containing a conductive agent but deteriorated in durability are used. By having a laminated structure of an unstretched outer resin layer that does not contain, it is found that a flame-retardant conductive seamless belt that does not easily generate cracks and has durability can be obtained.
The present invention has been made.

[0008] That is, the present invention is, your carbon black
An unstretched layer containing a material that deteriorates durability and a material that contains carbon black and deteriorates durability
A seamless belt comprising a laminate having a non-stretched and durable outer layer not having a surface conductivity of 1 × 10 ⁰ to 1 × 10 ¹³ Ω.
/ □, volume specific resistance value is 1 × 10 ⁰ to 1 × 10 ¹³ Ω · c
m, wherein a seamless belt made of a thermoplastic resin laminate is provided.

[0009]

DETAILED DESCRIPTION OF THE INVENTION (1) Resin composition The thermoplastic resin flame-retardant conductive seamless belt of the present invention comprises a resin composition comprising carbon black as a conductive filler and a thermoplastic resin. It is composed of a laminate of a stretch-resistant outer layer and an unstretched layer made of a resin composition comprising carbon black and a thermoplastic resin.

The thermoplastic resin used in the present invention includes polycarbonate, polyethylene terephthalate, polyetheretherketone, polyvinylidene fluoride, polyamide, acrylic, polypropylene, polysulfone, polyethersulfone and ethylenetetrafluoroethylene. Polymers, alkyl acrylate copolymers, polyester ester copolymers, polyether ester copolymers, polyether amide copolymers, polyurethane copolymers, etc., or a mixture thereof are used. .

[0011]Carbon black Carbon black used as a conductive filler
Acetylene black, furnace black, tea
There is tunnel black. The compounding amount is as follows.
3 to 25 parts by weight based on 00 parts by weight
Is done. The amount of this carbon black is seamless
Surface conductivity of 1 × 10⁰~ 1 × 10¹³Ω / □ range
And the volume resistivity is 1 × 10⁰~ 1 × 10¹³Ω ・ c
The amount is in the range of m. Specifically, the sheet for the photosensitive member substrate
When used for a mules belt, the surface conductivity is 1 × 1
0⁰~ 1 × 10⁶Ω / □, preferably 1 × 10⁰~ 1 ×
10^ThreeΩ / □, volume resistivity value is 1 × 10⁰~ 1 × 1
0 ⁶Ω · cm, preferably 1 × 10⁰~ 1 × 10^ThreeΩ
cm, seamless belt for intermediate transfer, transport
Seamless belt, fixing seamless belt, developing
When used for seamless belts etc., surface conductivity is 1
× 10^Five~ 1 × 10 ¹³Ω / □, preferably 1 × 10⁷~
1 × 10¹²Ω / □, volume resistivity value is 1 × 10^Five~ 1
× 10¹³Ω · cm, preferably 1 × 10⁷~ 1 × 10¹²
It is an amount that becomes Ω · cm.

If the amount is less than the above range, the conductivity is poor. If the amount exceeds the above range, the appearance of the seamless belt deteriorates and the material strength is unfavorably reduced. The surface of the seamless belt 6 is charged or charged on the surface 6b.
The operation of removing this charge by grounding from one of the rolls 8 and 9 or another roll is performed in a short time. Therefore,
Carbon black is blended in all layers, and it is necessary to maintain the volume resistivity. Carbon, copper,
A conductive filler of a metal powder such as silver may be used in combination.

Flame retardant The flame retardant used in the present invention is preferably composed of at least one selected from halogen-based or phosphorus-based compounds or a mixture thereof.

Examples of the halogen-based flame retardant include tetrachlorophthalic anhydride, tetrabromophthalic anhydride, chlorinated paraffin, chlorinated bisphenol A, brominated bisphenol A, tetrabromobenzene, tetrabromotoluene,
Hexabromobenzene, decabromodiphenyl ether, tetrabromoethane, 1,2-dichloro-3-bromopropane, 2-chloro-1,2,3,4-tetrabromobutane, 1,2-dibromo-1,1,2 , 2-tetrachloroethane and chlorinated naphthalene.

[0015] Examples of the phosphorus-based flame retardant include a phosphoric ester compound and red phosphorus. Examples of the phosphate compound include tricresyl phosphate, trioctyl phosphate, and octyl diphenyl phosphate. The compounding amount of the flame retardant is 5 to 30 parts by weight, preferably 10 to 25 parts by weight, based on 100 parts by weight of the mixed resin composition of the thermoplastic resin and the carbon black. If it is less than the above range, the flame retardancy is inferior. If it exceeds the above range, the material strength is undesirably reduced. An antimony-containing compound may be blended to enhance the flame retardant effect. A preferred compound is antimony oxide.

Additional Components The resin composition of the material forming the seamless belt may contain various additional components which are usually added to the resin composition, unless the properties aimed at by the present invention are impaired. . Such components include, for example, antioxidants, lubricants, release agents, dispersants, and ultraviolet absorbers.

Compounding method The above components can be compounded into pellets by a usual melt-kneading method, that is, using a single screw extruder, a twin screw extruder, a roll, a Banbury or the like. Desirable is a method of melt-kneading using a twin-screw extruder, extruding a strand from a die, and cooling to obtain pellets.

(2) Method for producing a seamless belt A method for producing a seamless belt includes a continuous melt extrusion method,
Known methods such as an injection molding method, a blow molding method, and a blown film molding method can be employed. A preferred production method is a continuous melt extrusion method.

As a desirable continuous melt extrusion molding method of a seamless belt, there is an internal cooling mandrel method or a vacuum sizing method of a downward extrusion method capable of controlling the inner diameter of an extruded tube with high accuracy. The extruded cylindrical film must be unstretched and have the required conductivity, uniform thickness, mechanical strength, and crack resistance. When the stretching operation is performed, the mechanical strength can be expected to be improved, but the uniformity of conductivity is impaired, and the film is easily torn in the stretching direction, so that the crack resistance is impaired. Furthermore, the stretching causes peeling at the interface between the conductive filler and the resin,
The conductive filler may fall off, resulting in uneven transfer. The tubular film is sliced in a direction perpendicular to the direction in which the film is taken into a seamless belt.

The seamless belt of the present invention comprises a thermoplastic resin composition containing carbon black and a flame retardant,
After melt-kneading the thermoplastic resin composition containing the carbon black but not containing the flame retardant with a separate extruder, the mixture is supplied to one co-extrusion circular die, and two layers or After laminating (laminating) three layers, a co-extrusion method in which the cylindrical laminated film is continuously melted from the die is preferably used to cut a two-layer or three-layer cylindrical film into slices.

(3) Seamless Belt The thickness of the obtained seamless belt is 30 μm or more and 1,000 μm or less. Preferably, it is 50 μm or more and 500 μm or less. When the thickness is less than 30 μm, the seamless belt is easily stretched, so that problems such as uneven color of an image occur, and the withstand voltage is insufficient, so that a voltage sufficient to impart a charge required for transfer cannot be applied. On the other hand, if the thickness exceeds 1,000 μm, it becomes difficult to perform flexible deformation, so that driving at a uniform speed by the small-diameter rolls 7, 8, and 9 is impaired. To provide the required charge,
A larger high-voltage power supply than necessary is required, which not only increases the cost, but also tends to cause a problem such as discharge between peripheral device parts because a high voltage is applied.

The seamless belt 6 includes a resin layer containing carbon black and a flame retardant, and an outer layer 6b of a resin containing carbon black but not containing a flame retardant. A preferred layer structure of the seamless belt 6 is a two-layer structure in which the inner layer 6a is a resin layer containing carbon black and a flame retardant, and the outer layer 6b is a resin layer containing carbon black and does not contain a flame retardant. The intermediate layer is a resin layer containing carbon black and a flame retardant, and the inner layer 6a and the outer layer 6b are three-layer products containing a carbon black but not containing a flame retardant.

In the case of a two-layer structure, the thickness ratio of the inner layer 6a and the outer layer 6b of the seamless belt is as follows: outer layer / inner layer = 2 to 1
/ 20, preferably outer layer / inner layer = 1 to 1/10. In the case of a three-layer structure, the thickness ratio of the inner layer, the intermediate layer, and the outer layer of the seamless belt is as follows: outer layer / intermediate layer / inner layer = 1/1
/ 1/1/40/1, preferably outer layer / intermediate layer / inner layer = 1/2/1 to 1/20/1. When the thickness of the outer layer is larger than this ratio, it becomes difficult to impart flame retardancy to the seamless belt. When the outer layer is smaller than this ratio, the durability when the seamless belt 6 is driven by the small-diameter rolls 7, 8, and 9 is impaired, and cracks are easily formed.

The seamless belt 6 may be used as it is as a seamless belt, or may be wound around a drum or a roll. Further, for the purpose of preventing meandering, reinforcing the end face, etc., the end face of the seamless belt having a predetermined size may be reinforced with heat-resistant tape or silicone rubber 13 or may be provided with a guide 14.

[0025]

The present invention will be further described below with reference to specific examples. (Example 1) Melt flow rate (MFR) is 5 g / 1
83 minutes by weight of a 0 minute (280 ° C.) polycarbonate resin (trade name, manufactured by Mitsubishi Gas Chemical Co., Ltd .; Iupilon E-2000); polybutylene terephthalate having an MFR of 4 g / 10 minutes (230 ° C.) [manufactured by Mitsubishi Kasei Corporation Product name: Novador 5020] 17 parts by weight and 14 parts by weight of acetylene black (product of Electrochemical Co., Ltd.) having a specific surface area of 70 m ² / g were kneaded and granulated at 270 ° C. using a vented twin-screw extruder.
A conductive polycarbonate resin (A) pellet was obtained.

A polycarbonate resin having an MFR of 5 g / 10 min (280 ° C.) [Iupilon E manufactured by Mitsubishi Gas Chemical Co., Ltd.]
-2000] 83 parts by weight, MFR 4 g / 10 min (23
0 ° C) polybutylene terephthalate [Mitsubishi Kasei Corporation
Novador 5020] 17 parts by weight and specific surface area 70
m ² / g acetylene black [product of Electrochemical Co., Ltd.]
14 parts by weight of the above mixture (100 parts by weight) and 15 parts by weight of a brominated bisphenol A-based flame retardant (trade name, manufactured by Teijin Chemicals Limited; Fireguard 7000) at 270 ° C. using a vented twin-screw extruder. The resulting mixture was kneaded and granulated to obtain a flame-retardant conductive polycarbonate resin (B).

The mixed and granulated flame-retardant conductive polycarbonate resin (B) is extruded at 265 ° C. from an extruder having a diameter of 25 mm so that the mixed and granulated conductive polycarbonate resin (A) becomes the outer layer 6b. 40 to be 6a
extruded at 270 ° C from an extruder of
A two-layer co-extrusion die having a diameter of 0 mm is extruded in the form of a molten cylindrical film below the annular die, and the extruded molten cylindrical film is mounted on a coaxial axis of the annular die through a support rod through a support rod. After contacting with the outer surface of the cooling mandrel and cooling and solidifying to form a cylindrical film, an outer layer / inner layer = 20 μm / 13 by a core installed in the cylindrical film and a roll installed outside.
A cylindrical film having a total thickness of 0 μm and a total thickness of 150 μm was taken out while holding the cylinder.

This was cut into a seamless belt having a thickness of 150 μm, a diameter of 130 mm, and a width of 200 mm. This seamless belt was measured using a resistance meter (trade name, manufactured by Mitsubishi Yuka Co., Ltd .; Hiresta IP) and electrodes (trade name, manufactured by Mitsubishi Yuka Co., Ltd .; HA) at a measurement voltage of 100 V and a measurement time of 10 seconds. However, the surface conductivity of the inner and outer surfaces is 1.1 × 10 ⁹ Ω / □, and a resistance meter (trade name of Mitsubishi Yuka Co., Ltd .; Hiresta IP) and an electrode [trade name of Mitsubishi Yuka Co., Ltd. J-BOX] and measuring voltage 100
V, the volume resistivity measured in a measurement time of 1 minute is 5.0 ×
It was 10 ⁹ Ω · cm.

The seamless belt UL-94V
The flame retardancy measured according to TM was VTM-2 class. On both inner end surfaces of the seamless belt 6, a single-sided adhesive biaxially-stretched polyethylene terephthalate 13 having a thickness of 50 μm and a width of 10 mm has a width of 5 mm and a height of 0.6.
A guide tape for reinforcing the end face treatment of the seamless belt to which a silicone rubber guide 14 having a diameter of mm was adhered was adhered (FIG. 2).

The obtained end-face treated reinforced seamless belt was rolled with a roll diameter of 25 mm and a roll speed of 100 mm /
The belt was set in the apparatus shown in FIG. 1 under the conditions of seconds, a belt tension of 10 kg / seamless belt full width, a temperature of 25 ° C., and a relative humidity of 55%, and a durability test was carried out. As a result, cracks occurred in the seamless belt for 80 hours continuously. Table 1 shows the results.

(Example 2) The conductive polycarbonate resin (A) pellets obtained by mixing and granulating in Example 1 were supplied to an annular die as an outer layer and an inner layer at 265 ° C from an extruder having a diameter of 25 mm. Pellets of the flame-retardant conductive polycarbonate resin (B) obtained by mixing and granulating in Example 1 were supplied to the above-mentioned annular die as an intermediate layer at 270 ° C. from an extruder having a diameter of 40 mm, and the temperature was set to 265 ° C.
Laminate into three layers in a co-extrusion annular die of 0 mmφ, co-extrude, cool and cool outer layer / intermediate layer / inner layer = 10 μm
A cylindrical film having a total thickness of 150 μm of / 130 μm / 10 μm was obtained.

Otherwise, a seamless belt was obtained in the same manner as in Example 1. The surface conductivity of the inner and outer surfaces of the obtained seamless belt is 1.3 × 10 ⁹ Ω / □, UL-94V
The flame retardancy measured according to TM was VTM-2.
When a durability test similar to that of Example 1 was performed using the apparatus shown in FIG. 1, cracks occurred for 90 hours in a row. Table 1 shows the results.

(Comparative Example 1) Pellets of the conductive polycarbonate resin (A) obtained by mixing and granulating in Example 1 were 25 mmφ for the outer layer and the inner layer of the seamless belt.
Kneading at 265 ° C from each extruder of 40mmφ,
A seamless belt was obtained in the same manner as in Example 1 except that the two-layer co-extrusion die having a diameter of 265 ° C. and 140 mmφ was respectively guided to a circular die and co-extruded at 265 ° C. The surface conductivity of the inner and outer surfaces of the obtained seamless belt was 1.2 × 10 ⁹ Ω / □,
The flame retardancy measured in accordance with UL-94VTM burned and showed no flame retardancy. In addition, when the same durability test as in Example 1 was performed using the apparatus shown in FIG. 1, cracks occurred for 105 hours in a row. Table 1 shows the results.

(Comparative Example 2) The flame-retardant conductive polycarbonate resin (B) pellets obtained by mixing and granulating in Example 1 were used as an outer layer and an inner layer for 25 mmφ, 40 m.
kφ from each extruder of mφ at 270 ° C.
A seamless belt was obtained in the same manner as in Example 1 except that the two layers were co-extruded into a 140 mmφ two-layer co-extrusion die at ℃ and co-extruded at 265 ° C. The surface conductivity of the inner and outer surfaces of the obtained seamless belt is 0.9 × 10 ⁹ Ω / □, UL-
The flame retardancy measured according to 94 VTM was VTM-1. When a durability test similar to that of Example 1 was performed using the apparatus shown in FIG. 1, cracks occurred for 11 hours in a row. Table 1 shows the results.

[0035]

[Table 1]

[0036]

The seamless belt of the present invention has excellent flame retardancy and durability.

[Brief description of the drawings]

FIG. 1 is a front view of an intermediate transfer device of an electrophotographic copying machine.

FIG. 2 is a perspective view of a seamless belt whose end face is reinforced.

[Explanation of symbols]

 Reference Signs List 1 photosensitive drum 2 charger 3 exposure optical system 4 developing device 5 cleaner 6 (flame-retardant) conductive seamless belt 6a inner surface 6b outer surface 7 transport roller 8 transport roller 9 transport roller 10 electrostatic transfer device 11 recording paper 12 extrusion roller 13 Reinforcing tape 14 Guide

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-63-202537 (JP, A) JP-A-64-26439 (JP, A) JP-A-63-188153 (JP, A) 89357 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) B65H 23/06 G03G 15/16 G03G 21/00

Claims (3)

(57) [Claims] 1. Carbon black and poor durability
Unstretched layer containing carbon black and carbon black
And a non-stretched durable outer layer not containing a substance deteriorating durability, comprising a laminate having a surface conductivity of 1 × 10 ⁰ to 1 × on the front and back surfaces of the seamless belt. A seamless belt made of a thermoplastic resin laminate, which has a resistivity of 10 ¹³ Ω / □ and a volume resistivity of 1 × 10 ⁰ to 1 × 10 ¹³ Ω · cm. 2. A seamless belt comprising a laminate having a layer containing carbon black and a flame retardant, and a durable outer layer containing carbon black and not containing a flame retardant. A thermoplastic resin laminate characterized in that the back surface has a surface conductivity of 1 × 10 ⁰ to 1 × 10 ¹³ Ω / □ and a volume resistivity of 1 × 10 ⁰ to 1 × 10 ¹³ Ω · cm. Seamless belt. 3. The thickness ratio of a durable outer layer to other layers.
2. The method according to claim 1, wherein the rate is 2 to 1/20.
2. The seamless belt according to 2.