JP3087723B2 - 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 which can be suitably used for an electroconductive substrate or the like used in an electrophotographic apparatus.

[0002]

2. Description of the Related Art Electrophotographic photoreceptors can be classified into drum-shaped and belt-shaped electrophotographic photosensitive members. The present invention relates to a seamless belt applicable to a belt-shaped photoconductor conductive substrate. Conventionally, a belt-shaped photoconductor conductive substrate is made of, for example, a polyethylene terephthalate film on which aluminum is vapor-deposited, and a photoconductor made of these is formed by forming a photoconductive layer on the film, and then bonding both ends of the film to form a belt. Was produced.

[0003]

However, in the photoreceptor manufactured in this way, the seam (joint) portion at the time of lamination does not show photoconductivity, so that no image signal is applied to the seam portion. As described above, it is necessary to control the driving of the photoconductor belt, and therefore, the driving portion of the photoconductor belt is complicated, the use position of the photoconductor is fixed, and the life of the photoconductor is shortened. There is.
In addition, in order to solve the above problems, a seamless conductive substrate using electroformed nickel has been proposed. However, since the substrate is a metal, the shapeability and flexibility are poor and practicality is poor. There's a problem. SUMMARY OF THE INVENTION The present invention is to solve the problems of the conventional conductive belt at once.

[0004]

The present invention has succeeded in producing a seam-free belt by an inflation molding method by using a specific thermoplastic composition as a material of the belt. That is, the gist of the present invention is to provide a resin composition 1 comprising 60 to 98% by weight of a polycarbonate resin and 40 to 2% by weight of a polyester resin.
3 to 2 parts of conductive carbon black per 100 parts by weight
0 parts by weight, water content is 0.5% or less
Strength obtained by molding the resin composition according to the inflation molding method at a tensile strength of 6 kg / mm ² or more and a tensile elongation of 0 kg / mm ² or more.
20% to 20% of the seamless belt ( excluding the electrophotographic photosensitive member conductive substrate) used in the electrophotographic apparatus.

[0005]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Constituent Components The present invention is to form a resin composition comprising a thermoplastic resin, a polyester resin having compatibility with the thermoplastic resin and conductive carbon black by a specific molding method. . Thermoplastic resin As the thermoplastic resin used in the present invention, known resins can be used, and preferably, the tensile strength is 6 kg / mm ^2.
Above, preferably 7 to 9 kg / mm ² , tensile elongation of 1 to 1
It is 150%, preferably 1 to 100%. This tensile elongation varies depending on the blending of other components, especially carbon black, and the stretching state during molding, and does not necessarily indicate the numerical value of the product substrate of the present invention.

More specifically, acrylic resins such as polycarbonate resin and polymethyl methacrylate, styrene resins such as polystyrene and styrene / maleic anhydride copolymer, polypropylene and poly (4-methylpentene-1)
And polyolefin resins, such as polyvinylidene fluoride, polyester resins such as polyethylene terephthalate (PET) and polybutylene terephthalate (PBT), and liquid crystal polyester resins such as a copolymer of parahydroxybenzoic acid and PET. . These may satisfy the mechanical properties of the present invention by post-treatment such as crosslinking after molding. Particularly preferred thermoplastics are polycarbonates (especially aromatic polycarbonates), polymethyl methacrylate, and polyvinylidene fluoride.

Thermoplastic Polymer The thermoplastic polymer blended with the above-mentioned thermoplastic resin in the present invention is one having a degree of compatibility that is not completely compatible with the thermoplastic resin but does not cause delamination. Is done. As a measure of the compatibility, there is one having a similar molecular structure or one having a similar structural unit in the molecular structure. Further, those having relatively similar solubility parameter values may be selected.

Specifically, for example, for polycarbonate, polyalkylene terephthalate such as PET or PBT, those having an ester bond in the main chain such as polyester elastomer, polymethyl methacrylate or ethylene / ethyl acrylate copolymer ( (E.g., ethyl acrylate content of 20% or more) having an ester bond in the side chain. A small amount of a compatibilizer may be used to improve compatibility and prevent delamination. The thermoplastic polymer blended in the thermoplastic resin is not completely compatible with each other and shows a dispersed state such as a network structure or a sea-island structure.

In the dispersed state where the matrix and the dispersed phase are formed, the particle size of the dispersed phase in the matrix is not particularly limited in the case of a sea-island structure, but is preferably 10 μm or less, particularly preferably 5 μm or less from the viewpoint of delamination. . However, from the viewpoint of conductivity, a network structure is more preferable. Note that the dispersed state need not be formed by only two kinds of polymers, but may be formed in a state where carbon black is added. The compounded carbon black has a higher affinity for the polymer forming the dispersed phase than the matrix, and the dispersed state is significantly involved in the formation of the conductive path by the carbon black particles. The compatibility of the polymer is important.

Conductive carbon black The carbon black used in the present invention has a BET specific surface area of at least 500 m ² / g, particularly 600 m ² by N ₂ adsorption.
^A compound having a content of ² / g or more is preferred because a small amount of the additive can impart necessary conductivity to the composition. In particular, furnace black XCF (Extra Conductive F)
urnace), SCF (Super Conductor)
live Furnace), CF (Conductive)
e Furance) and SAF (Super Abr)
Asion Furnace is particularly preferred. XC
Examples of F include Ketjen Black International's “Ketjen Black EC” and Cabot's “Vulcan XC-72”, etc., and examples of SCF's are Cabot's “Vulcan SC”, “Vulcan P” and Degussa.
"Colax L" etc. and CF as Cab
There are "Vulcan C" of "ot", "Conductex SC" of "Columbian" and the like. As SAF, "Asahi # 90" of Asahi Carbon Co., "Diablack A" of Mitsubishi Chemical Industry Co., Ltd. and "Cabot" Balkan 9 "
Etc. These may be used in combination. Further, other carbon black such as acetylene black can be used as long as it does not exceed half the amount and the BET specific surface area by N ₂ adsorption after blending is 500 m ² / g or more.

Auxiliary Materials The resin composition of the present invention can contain various other auxiliary materials that can be contained in the thermoplastic resin composition unless the object of the present invention is particularly hindered. Specifically, for example, there are an antioxidant, a lubricant, a release agent and the like. Composition The composition of the resin composition is polycarbonate resin 60 to 9
The conductive carbon black is used in an amount of 3 to 20 parts by weight, preferably in an amount of 100 to 100 parts by weight of 8% by weight, preferably 70 to 97% by weight and 40 to 2% by weight, preferably 30 to 3% by weight of the polyester resin. 3.5 to 18 parts by weight are blended.

With respect to the above mixing ratio, when the mixing ratio of the resin composition is out of the above range, the dispersion of the carbon black particles becomes poor and the conductivity of the resin composition becomes low. Can no longer be used. On the other hand, with respect to carbon black, if it is less than the above range, the conductivity will be low, and it will not be possible to use it as a photoconductor conductive substrate. On the other hand, when the amount is more than the above range, the moldability of the resin composition deteriorates, and inflation molding becomes impossible.

The blending method The thermoplastic resin, thermoplastic polymer, conductive carbon black and the like to be blended may be molded as they are by dry blending, but are usually melt-kneaded, that is, a single screw extruder,
Pellets can be formed by applying a twin-screw extruder, a roll, a Banbury or the like. At the time of this production, it is necessary to sufficiently control the water content of each component. The water content of each component is 0.5% by weight or less, preferably 0.2% by weight or less, and particularly preferably 1000 ppm or less. Exceeding this range may adversely affect the appearance of the film.
In addition, it is necessary to pay attention to moisture when storing the composition after production, and it is preferable to control the moisture content of the composition itself to 0.5% by weight or less. Therefore, means such as hot-air drying or reduced-pressure drying is employed as necessary.

Resin Composition The resin composition obtained by the present invention has molding processability suitable for inflation molding. For use as a photoreceptor substrate in the present invention, the blown film has a tensile strength of 6 kg / mm ² or more, preferably 7 kg / mm ² or more, and a tensile elongation of 0 to 20%, preferably 1 to 10%. It is particularly preferably 2 to 5%, and when used as a substrate for a photoreceptor, has a volume resistivity of 10 ³ Ω.
It is necessary to have a high conductivity of less than .cm, preferably less than 10 ² Ω · cm.

Molding method The present invention relates to a method for producing the above resin composition by a method for producing a tubular film, specifically, an inflation molding method.
It is formed into a seamless belt with a uniform diameter and thickness. The seamless belt of the present invention preferably does not generate folds during molding, and a particularly preferred molding method therefor is described in Japanese Patent Application No. 63-55445. That is, the tubular resin film extruded from the annular die mounted on the extruder is cooled and solidified by contacting the cooling mandrel while continuously supplying and removing a gas whose supply pressure and supply amount are controlled inside thereof. , By the method of continuous withdrawal while maintaining the tube state,
A seamless belt having no folds and a uniform diameter and thickness can be obtained.

In the embodiments of the present invention, the electrophotographic photosensitive member is of a function-separated type, but the present invention is not limited to these photosensitive layers, and a seamless belt can be used regardless of the presence or absence of the photosensitive layer. It also encompasses any use that is effective as a conductive substrate in the shape of a circle.

[0017]

EXAMPLES In the following Examples and Comparative Examples, various evaluations were made by the following methods. Method for Evaluating Moldability The evaluation of moldability of the conductive thermoplastic resin composition is based on the evaluation of flowability, which is one index of moldability, according to M.P. F. R.
Was measured. The measurement was performed under the condition of a load of 2.16 kg at an appropriate measurement temperature for each of the thermoplastic resins used in the conductive thermoplastic resin composition.

Method for Evaluating Mechanical Strength The mechanical strength of the obtained conductive thermoplastic resin composition was measured according to JIS K-6758 by measuring the tensile strength and elongation at the yield point. Preparation of Electrophotographic Photoreceptor In the examples of the present invention, a function-separated type electrophotographic photoreceptor was used. Metal-free phthalocyanine treated by an acid-based method was used as the charge generator, and p-diethylaminobenzaldehyde- (diphenylhydrazone) was used as the charge transfer agent.

Polycarbonate (Iupilon E-2000 manufactured by Mitsubishi Gas Chemical Co., Ltd.) was used as a film-forming resin in a ratio of charge generating agent / polycarbonate of 1: 1. In the photoreceptor, a charge generation layer is formed to a thickness of 1 μm on a conductive belt made of the conductive thermoplastic resin composition by a seamless belt molding machine, and a charge transfer layer is further formed thereon to a thickness of 30 μm. Obtained by filming.

Electrophotographic Characteristics Measurement Method The electrophotographic characteristics of the obtained electrophotographic photosensitive member were measured by the following method. After being corona-charged at a voltage of -6 kV by a static method and held in a dark place for 10 seconds to measure an initial surface potential using a surface potentiometer (trade name, model 362A), the xenon lamp light was passed through a monochromator. The photosensitive member was irradiated with monochromatic light having a wavelength of 780 nm. Then, the time (second) required for the surface potential to decay to １ ／ was obtained, and the light sensitivity (cm ² / mJ) was calculated.

Example 1 Melt flow rate was 4.6 g / 10 min (280 ° C.,
2.16 kg) of 94% by weight of polycarbonate and a melt flow rate of 4.32 g / 10 min (230 ° C, 2.
11 parts by weight of Ketjen black having a specific surface area of 800 m ² / g were fed to a twin-screw extruder per 100 parts by weight of a resin composition (16 kg) of 6% by weight of polybutylene terephthalate (no layer separation was observed in this composition) And kneaded and granulated.

For forming the obtained pellets into a tube, an apparatus described in Japanese Patent Application No. 63-55445 was used. That is, a support pipe rod is fixed on the same axis on the annular die mounted on the extruder, and a cooling mandrel is fixed concentrically to this support pipe rod, and the support rod controls the internal pressure of the extrusion tube. A continuous gas supply / discharge pipe and a heat medium circulation pipe in the cooling mandrel are provided. In addition, a cooling ring that cools the extrusion tube with cold air from the outside is disposed concentrically between the annular die and the cooling mandrel.

The tube-shaped conductive resin film extruded downward at 280 ° C. from the annular die is cooled by the cool air blown from the cooling ring on the outer periphery, and the inside of which is controlled by the supply pressure and supply air. Continuous supply
By keeping the internal pressure constant by removing it, it contacts the cooling mandrel and cools and solidifies, and is continuously taken off while maintaining the tube state by the nip rolls arranged inside and outside the tube below the cooling mandrel, seamless Molded into belt. The conductive performance of the obtained seamless belt was measured. Further, a photosensitive layer was formed on the obtained seamless belt, and the electrophotographic characteristics were evaluated. Further, as a result of performing image output evaluation of the obtained photoreceptor, a clear image was obtained.

Comparative Example 1 A seamless belt was produced in exactly the same manner as in Example 1 except that the same amount of carbon black having a specific surface area of 240 m ² / g was used instead of using Ketjen black. The same evaluation as in Example 1 was performed. Comparative Example 2 A seamless belt was prepared in the same manner as in Example 1 except that the amount of Ketjen Black was changed to 25 parts by weight, and the same evaluation as in Example 1 was performed.

Comparative Example 3 In Example 1, the blending amount of polycarbonate was 65% by weight, and the blending amount of polybutylene terephthalate was 35% by weight.
A seamless belt was prepared in exactly the same manner as in Example 1 except that the evaluation was made, and the same evaluation as in Example 1 was performed. Results The results obtained are shown in Table 1 for both Examples and Comparative Examples.

[0026]

[Table 1]

[0027]

The seamless belt of the present invention comprises a composition in which conductive carbon black is blended in a specific resin blend,
It is obtained by inflation molding, and when used as a photoreceptor substrate, it is possible to increase the durability of the photoreceptor and increase the image output speed. Further, by adjusting the conductivity, it can be used as another functional component used in an electrophotographic apparatus.

────────────────────────────────────────────────── ─── Continued on the front page (51) Int.Cl. ⁷ Identification code FI G03G 15/00 G03G 15/00 // (C08L 69/00 67:02) B29K 69:00 B29L 29:00 (72) Inventor Shinji Horie 1 Toho-cho, Yokkaichi-shi, Mie Pref. In the Yokkaichi office of Mitsubishi Chemical Co., Ltd. 188153 (JP, A) JP-A-2-233765 (JP, A) Japanese Utility Model Application Laid-Open No. 61-24749 (JP, U)

Claims (1)

(57) [Claims] 1. 60% to 98% by weight of a polycarbonate resin
And 100 to 100 parts by weight of a resin composition consisting of 40 to 2% by weight of a polyester resin,
20 parts by weight, water content is 0.5% or less
Tensile strength 6 kg / mm ² or more, tensile elongation 0 or more obtained by molding a certain resin composition by an inflation molding method.
Seamless belt used in 20% electrophotographic apparatus (excluding electrophotographic photosensitive member conductive substrate) .