JPH1063029A - Seamless film belt - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a seamless film belt less liable to elongate and crack and capable of preventing the sticking of a toner to the surface of the belt by producing the seamless film belt having a laminated structure consisting of at least two layers so that it has the modulus of elasticity of the outer layer higher than that of the inner layer. SOLUTION: The seamless film belt 1 having a laminated structure consisting of at least two layers is produced so that the modulus of elasticity of the outer layer 2 is made higher than that of the inner layer 3. The outer layer 2 is formed using a resin having >=10,000kgf/cm<2> modulus of elasticity and the inner layer 3 is formed using a resin having <=10,000kgf/cm<2> modulus of elasticity. The resin having >=10,000kgf/cm<2> modulus of elasticity is less liable to elongate but is hard and brittle. The resin having <=10,000kgf/cm<2> modulus of elasticity is less liable to crack but is liable to elongate. The especially pref. modulus of elasticity of the outer layer 2 is 20,000-40,000kgf/cm<2> and that of the inner layer 3 is 400-5,000kgf/cm<2> .

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a seamless film belt used for an electrophotographic copying machine, a printer, a facsimile and the like, and more particularly to a seamless film belt which is hard to stretch and hard to break and has excellent durability.

[0002]

2. Description of the Related Art Conventionally, a seamless film belt has been frequently used in an intermediate transfer device such as an electrophotographic copying machine, a transfer separation device, and a charging device. They are,
An intermediate transfer belt, a transfer conveyance belt, a photoreceptor belt, etc., all of which are preferably seamless film belts having no joint from the viewpoint of toner cleaning necessity and uniformity of electric resistance.

For example, a seamless film belt used for an intermediate transfer belt needs to have appropriate conductivity in order to electrostatically transfer toner in addition to heat resistance. Further, in order to prevent a so-called filming phenomenon in which the toner adheres to the belt surface as the belt is used, compatibility between the surface material and the toner must be considered. As a belt material which satisfies such properties, generally, a thermoplastic resin such as polycarbonate or polyethylene terephthalate as a basic component to which conductivity is imparted is used (Japanese Patent Application Laid-Open No.
311263). However, a belt formed from such a material does not stretch during running use, but has a problem in that it is cracked due to bending fatigue and cannot be used for a long time.

In an attempt to solve this problem, a seamless tube having a soft surface and sufficient strength has been synthesized by blending thermoplastic polyalkylene terephthalate with thermoplastic aromatic polycarbonate (JP-A-4-313775). ), When this was used for a seamless film belt, the improvement in flex fatigue was insufficient. Japanese Unexamined Patent Application Publication No. 5-200904 discloses a fluorine resin having excellent flex fatigue resistance as a belt material. , Because the tensile modulus is small, the belt stretches during use,
There is a problem that image unevenness occurs.

Further, there has been proposed a seamless film belt having a two-layer structure of an inner conductor and an outer dielectric for the purpose of imparting appropriate conductivity and preventing a filming phenomenon, which compensates for the drawbacks of the single-layer belt. Kaihei 6-1308
30, JP-A-62-211678). In the former example, both the inner layer and the outer layer of the belt were made of a thermoplastic resin, so that the belt was inferior in bending resistance. In the latter example, the lamination was performed with an adhesive, so that there was a disadvantage that interfacial peeling was likely to occur.

As a further example of a multi-layer belt, PVDF
A three-layer structure of / MMA-BA copolymer / PC-PBT blend has been proposed (Japanese Patent Laid-Open No. 5-105259). In this three-layer structure, polycarbonate is used for the inner layer to suppress elongation, and the toner is used for the surface layer. Fluorine-based resin is used to prevent adhesion. However, this surface layer is excellent in the initial toner release property, but has the disadvantage that it is easily damaged due to the softness of the material, and is disadvantageous for maintaining the toner fixation resistance for a long time.

[0007]

As described above, in a seamless film belt having a single-layer structure, a method of simply blending a "hard" component and a "soft" component negates each other's characteristics, and the purpose and the purpose of the present invention are as follows. It is not possible to obtain a “belt that is difficult to stretch and break”.

In a belt having a laminated structure,
Laminating a fluorine-based soft material on a polycarbonate-based hard material significantly reduces cracks and the like due to bending.However, since the soft material is placed on the surface side, new problems such as abrasion and toner sticking due to abrasion are caused. Problems arise.

The present invention has been made in view of the above problems, and provides a durable seamless film belt which is hardly stretched, hardly cracked, and can prevent toner from sticking to the surface for a long time. With the goal.

[0010]

According to the present invention, in a seamless film belt having a laminated structure of at least two layers, an elastic modulus of an outer layer is larger than an elastic modulus of an inner layer. In the belt, preferably, the elastic modulus of the outer layer is 10,000 kgf / cm ² or more,
The elastic modulus of the inner layer is 10,000 kgf / cm ² or less.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS In the present specification, the term "outer layer" refers to a surface layer of a seamless film belt, and in the case of an intermediate transfer belt, is a side in contact with a photosensitive drum or a recording paper. Is the side in contact with the electrostatic transfer device or the transport roller.

FIG. 1 shows a partially enlarged sectional view of the seamless film belt of the present invention. In the figure, 1 indicates a seamless film belt, 2 indicates an outer layer, and 3 indicates an inner layer.

As one embodiment of the present invention, as disclosed in JP-A-5-105259, an intermediate layer is provided between an outer layer (surface layer) and an inner layer to form a three-layer seamless film belt. Is also good.

The outer layer material of the seamless film belt of the present invention is most preferably a thermoplastic resin, and particularly includes the following: polypropylene, polyethylene, propylene ethylene block or random copolymer, styrene-butadiene, styrene. Butadiene / styrene block copolymer or its hydrogenated derivative, polybutadiene, polyisobutylene, polyamide, polyacetal (POM), polyarylate, polycarbonate (P
C), polyphenylene ether (PPE), polyethylene terephthalate (PET), polysulfone, polyethersulfone, polyphenylene sulfide (PP
S), polybutylene terephthalate (PBT), polyether ether ketone (PEEK), polyvinylidene fluoride (PVDF), ethylene tetrafluoroethylene copolymer (ETFE), tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer (PFA) , Tetrafluoroethylene-hexafluoropropylene copolymer (FEP), polyvinyl fluoride, acrylic, alkyl acrylate copolymer, polyether ester copolymer, polyether amide copolymer, polyurethane copolymer and the like. In consideration of toner filming resistance, polycarbonate is preferably used. In the present invention, among the above-mentioned thermoplastic resins, only one kind or a mixture of these can be used as the outer layer material.

The inner layer material of the seamless film belt of the present invention is most preferably a thermoplastic elastomer, and particularly includes the following: polystyrene elastomer, polyolefin elastomer, polyvinyl chloride elastomer, polyurethane elastomer. , Polyamide elastomer, syndiotactic 1,2B
R, trans 1,4-IR, metal carboxylate ion cluster, crystalline polyethylene, fluororesin. In consideration of heat resistance, a polyurethane-based elastomer, a polyester-based elastomer, and a polyamide-based elastomer are preferably used. As in the case of the outer layer material, in the present invention, one of the above-mentioned thermoplastic elastomers or a mixture of these thermoplastic elastomers can be used as the inner layer material.

Each layer constituting the seamless film belt of the present invention is blended with an electric resistance adjusting agent,
Conductivity can be imparted as needed. As the electric resistance adjusting agent, carbon black such as acetylene black, Ketjen black, furnace black and channel black is preferably used. The amount of the electric resistance adjusting agent is appropriately determined according to the conductivity required for each layer.

Further, in the seamless film belt of the present invention, various additional components can be blended as long as the effect is not impaired. Such additional components include, for example, fillers, antioxidants, lubricants, antistatic agents, release agents, and the like.

Conventionally, in a seamless film belt having a laminated structure, it has been considered that it is desirable to arrange a material having a low elastic modulus in the outer layer and a material having a high elastic modulus in the inner layer. For example, Japanese Patent Laid-Open No. 5-105259 proposes to use a polycarbonate for the inner layer and a polytetrafluoroethylene-based resin for the outer layer (column 2, lines 1 to 3). On the other hand, the seamless film belt of the present invention comprises an outer layer 2 having a large elastic modulus and an inner layer 3 having a small elastic modulus.

Another feature of the present invention is that the outer layer 2 is made of a resin material having an elastic modulus of 10,000 kgf / cm ² or more and the inner layer 3 is made of a resin material.
Is formed of a resin material having an elastic modulus of 10,000 kgf / cm ² or less. It has a modulus of 10,000 kg
If it is f / cm ² or more, the resin material is hard to elongate, but it is hard and brittle. If it is 10,000 kgf / cm ² or less, it is hard to crack, but it is easy to elongate. Particularly preferably, the elastic modulus of the outer layer 2 is 20,000 to 40,000 kg.
f / cm ² , and the elastic modulus of the inner layer 2 is 400 to
It is in the range of 5,000 kgf / cm ² . According to the present invention, by combining such an outer layer material and an inner layer material, it is possible to obtain a seamless film belt which has the advantages of both materials and is hard to stretch and hard to break.

In the seamless film belt of the present invention, the ratio of the thickness of the outer layer 2 to the thickness of the inner layer 3 varies depending on the resin material used, but the elastic modulus of the molded product belt is 7,000 kgf /.
It is desirable to set it to be at least cm ² . When the elastic modulus is less than 7,000 kgf / cm ² , when used as an intermediate transfer belt, blurring and unevenness of an image due to belt elongation occur.

The thickness of the seamless film belt of the present invention is preferably in the range of 50 to 1,000 μm,
More preferably, it is in the range of 100 to 700 μm. 50μ
When the thickness is less than m, the seamless film belt is easily stretched, so that the problem such as color unevenness of the image occurs as described above. In addition, the charged voltage is insufficient, and it becomes impossible to apply a voltage sufficient to provide a charge required for transfer. On the other hand, 1,0
If the thickness exceeds 00 μm, it becomes difficult to perform flexible deformation, so that the roller cannot be driven at a constant speed by the small-diameter roll, and an image transfer shift occurs. In addition, since the capacitance is small, it is not possible to apply electric charges required for transfer unless a high voltage is applied, which not only increases the cost and size of the power supply device but also reduces the discharge between peripheral device parts. Problems also arise.

The seamless film belt of the present invention is desirably manufactured by a two-layer coextrusion method in which the outer layer material component and the inner layer material component are melt-extruded simultaneously and continuously from one die in a molten state. Injection molding and blow molding are discontinuous intermittent molding methods.Belts manufactured by these methods have non-uniform melt orientation in the longitudinal direction perpendicular to the circumferential direction, and consequently non-uniform conductivity. Problem. By a two-layer coextrusion method, a film obtained by forming a tube is continuously cut into a predetermined length to produce a seamless film belt.

The main application of the seamless film belt according to the present invention is an intermediate transfer belt for an electrophotographic apparatus, but other members in the apparatus (for example, a photoreceptor belt, a fixing belt, a transfer conveyance belt), and OA equipment. It can be widely used as a recording material belt base material for various printers.

[0024]

The present invention will be described by way of examples and comparative examples, which do not limit the scope of the present invention.

[0025] (Example 1) elastic modulus 21,300kgf / cm ² polycarbonate as the thermoplastic resin of the outer layer (Panlite K-1300, manufactured by Teijin Chemicals Ltd.), elastic modulus 580 kgf / cm ² as the thermoplastic elastomer of the inner layer
Polyester elastomer (Hytrel 4777,
Toray and DuPont) were selected. 40m each
It is melt-extruded by a twin screw extruder with a vent of mφ, led to a 170 mmφ two-layer co-extrusion annular die, laminated in the die, extruded into a tube below the annular die, and mounted coaxially with the annular die. It was brought into contact with the outer surface of the cooling mandrel, cooled, solidified, and taken off to produce a seamless tube. Next, the outer layer / inner layer is adjusted to 75/75 μm (total thickness of about 150 μm) by the core positioned in the seamless tube and the roll positioned on the outer side, and is taken out without folds while maintaining the cylindrical shape. The seamless tube was cut into a predetermined length to obtain a seamless film belt of the present invention.

(Example 2) The outer layer had an elastic modulus of 28,000
A polyethylene terephthalate of 0 kgf / cm ² (Diaalloy TW-90E, manufactured by Mitsubishi Rayon Co., Ltd.) and a polyester elastomer having an elastic modulus of 1,150 kgf / cm ² (Perprene S-2001, manufactured by Toyobo Co., Ltd.) were selected as the inner layer. The thickness of the outer layer and the inner layer is defined as outer layer / inner layer = 50/10
A seamless film belt of the present invention was manufactured in the same manner as in Example 1 except that the thickness was changed to 0 μm.

(Embodiment 3) The elastic modulus is 21, 30 as the outer layer.
0 kgf / cm ² polycarbonate (Panlite-1
300, manufactured by Teijin Chemicals Limited), elastic modulus 800 kg as inner layer
f / cm ² polyurethane elastomer (Rezamine P
-8765, manufactured by Dainichi Seika Co., Ltd.). A seamless film belt of the present invention was manufactured in the same manner as in Example 1 except that the thickness of the outer layer and the inner layer was changed to outer layer / inner layer = 70/80 μm.

(Embodiment 4) The elastic modulus is 21, 30 as the outer layer.
0 kgf / cm ² polycarbonate (Panlite-1
300, manufactured by Teijin Chemicals Limited), elastic modulus of 2,100 as inner layer
A kgf / cm ² polyamide-based elastomer (nylon 12 elastomer E62-S1, manufactured by Daicel Hulls) was selected. Outer layer / inner layer thickness: outer layer / inner layer = 60
A seamless film belt of the present invention was produced in the same manner as in Example 1 except that the thickness was changed to / 90 μm.

Comparative Example 1 The polycarbonate (Panlite K-1300, manufactured by Teijin Chemicals Ltd.) having an elastic modulus of 21,300 kgf / cm ² used for the outer layer of Example 1 was 170 mmφ.
Extruded from an extruder, and the thickness was 150
It was formed into a belt having a thickness of μm to obtain a single-layer seamless film belt.

Comparative Example 2 The procedure of Comparative Example 1 was repeated except that the outer layer of Example 2 used polyethylene terephthalate (diaalloy TW-90E, manufactured by Mitsubishi Rayon Co., Ltd.) having an elastic modulus of 28,000 kgf / cm ^2. Thus, a single-layer seamless film belt was manufactured.

(Comparative Example 3) The same procedure as in Comparative Example 1 was carried out except that a polyester elastomer having a modulus of elasticity of 580 kgf / cm ² (Hytrel 4777, manufactured by Toray Industries, manufactured by Dupont) was used for the inner layer of Example 1. To produce a single-layer seamless film belt.

Evaluation Test In order to test the durability of each seamless film belt obtained in Examples and Comparative Examples, it was mounted on an actual machine (40,000 copies using Ricoh Pretailer 550, manufactured by Ricoh) for a certain period of time. Table 1 shows the results of evaluation of the belt after use as an intermediate transfer belt, cracking, elongation, and interfacial peeling (peeling between the outer and inner layers).

[0033]

[Table 1]

All the evaluations in Table 1 were made by visually observing the belt after the test, and the results were recorded. When an abnormality was found with respect to cracking and interfacial peeling, it was evaluated as x, and when no abnormality was observed, it was evaluated as ○. The belt elongation was evaluated as x when there was a shift in the image of the printed matter, and as o when it did not. Comparative Examples 1 to
Since all of the seamless film belts of No. 3 were a single layer, there was no interfacial peeling (indicated by-).

From the test results shown in Table 1, the seamless film belt of the present invention was hardly broken and hardly stretched, but the seamless film belt of the comparative example had only one property.

[0036]

As described above, according to the present invention, the seamless film belt has a laminate structure of at least two layers in which the elastic modulus of the outer layer is larger than the elastic modulus of the inner layer. A seamless film belt that is unlikely to be obtained is obtained. Therefore, when copying and printing using the seamless film belt of the present invention as an intermediate transfer belt of an electrophotographic apparatus, image displacement due to belt elongation and generation of cracks at the end of the belt do not occur, and stable and long-lasting high image quality can be obtained. A uniform image can be obtained with high accuracy.

[Brief description of the drawings]

FIG. 1 is a partially enlarged sectional view of a seamless film belt of the present invention.

[Explanation of symbols]

 1 Seamless film belt 2 Outer layer 3 Inner layer

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁶ Identification code Agency reference number FI Technical display location G03G 15/16 G03G 15/16

Claims (2)

[Claims] 1. A seamless film belt having a laminated structure of at least two layers, wherein an elastic modulus of an outer layer is larger than an elastic modulus of an inner layer. 2. The elastic modulus of the outer layer is 10,000 kgf /
cm ² or more, and the elastic modulus of the inner layer is 10,000 kgf.
² / cm ² or less.