JP2000075729A - Endless belt drive for electrophotographic equipment - Google Patents

Abstract

(57) [Problem] To prevent the separation of guide ribs by correcting the run-out of an endless belt by a driving roller,
Provided is a driving device for an electrophotographic apparatus which can be stably driven for a long period of time. SOLUTION: In a drive device of an endless belt in which a flexible film-shaped base material is formed in a ring shape and guide ribs made of a flexible material are joined to the inner peripheral surface thereof along side edges, guides are provided at both ends. An endless belt for an electrophotographic apparatus, comprising: a driving roller having a small-diameter portion for receiving a rib for use therein, the driving roller being inclined so that the peripheral surface of the small-diameter portion has a small diameter in an end direction. apparatus.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an endless belt drive for an electrophotographic apparatus. More specifically, the present invention relates to a driving device for an endless belt for an electrophotographic apparatus, which can stably drive an endless belt having a guide rib on an inner peripheral surface for a long period of time.

[0002]

2. Description of the Related Art In recent years, electrophotographic image forming methods have been widely used in copiers, printers and the like, since high quality images can be obtained immediately. As the core photoreceptor, an endless belt-shaped electrophotographic photoreceptor is widely used because it has a flexible property and a high degree of freedom in arrangement in an apparatus. The endless belt-shaped photoreceptor 20 is formed by laminating a metal layer on a synthetic resin film, and cutting a photoreceptor sheet on which a photoreceptor layer such as a charge generation layer and a charge transport layer is formed into predetermined dimensions. As shown in FIG. 4, both ends are fused and formed into an annular shape using an ultrasonic sealing machine or the like, and are used as an image forming mechanism.
21 is a charger, 22 is an exposure optical system, 23 is a developing device, 2
4 is a cleaner, 25 is a transfer charger, and 26 is a sheet for transfer.

In an electrophotographic apparatus, an intermediate transfer belt 30 is used. As shown in FIG.
As shown in FIG. 5, the image developed by the developing device 23 on the photosensitive drum 20a is temporarily transferred onto the intermediate transfer belt 30, and the image is transferred to the paper 26 again. Thus, there is a problem that the endless belt-shaped electrophotographic photosensitive member 20 or the intermediate transfer belt 30 is apt to meander due to a lateral force applied during running.

For this reason, as shown in FIG. 6, the endless belt-shaped photoreceptor 20 and the like are joined along a side edge on the back surface thereof with a rib material made of a rubber-like flexible material to form a rib 31 for guiding. Then, the rib 31 is fitted into the groove 33 of the roller 32 and run to prevent meandering. However, when the lateral movement of the endless belt-shaped photoreceptor 20 or the like is regulated by the groove 33 of the roller 32, the guide rib 31 is pressed against the side wall surface of the groove 33 and receives a pressing force. In order to concentrate on the root portion on the side in contact with the side wall surface of the guiding rib 31, the guiding rib 3
There is a problem that the bonding of No. 1 peels off.

[0005]

SUMMARY OF THE INVENTION The present invention reduces the lateral load applied to the guide ribs by suppressing the meandering of the endless belt during traveling by the structure of the drive roller. An object of the present invention is to provide a driving apparatus for an electrophotographic apparatus which can be stably driven for a long time by preventing abrasion.

[0006]

SUMMARY OF THE INVENTION The present invention has been made as a result of intensive studies from such a viewpoint. A flexible film-like base material is formed in an annular shape and the inner peripheral surface thereof is formed along a side edge. In an endless belt driving device in which guide ribs made of a flexible material are joined, a small-diameter portion for receiving the guide rib is provided at both ends so that the peripheral surface of the small-diameter portion has a small diameter in the end direction. It is an object of the present invention to provide an endless belt driving device for an electrophotographic apparatus, wherein the driving device is provided with an inclined driving roller.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Endless belt 1 used in the present invention
As shown in FIG. 1, a flexible film-shaped substrate 2 is formed in an annular shape and a rib 3 is joined thereto. Note that, in the present invention, a sheet and a film are used as synonyms, and identification by a film thickness is not performed. In the case where the electrophotographic photosensitive member is used as the endless belt 1, a conductive support is used as the flexible film-shaped substrate 2, and a photosensitive layer is formed on the conductive support.

The conductive support is preferably a laminate of a biaxially stretched film and a metal layer. Examples of the material of the biaxially stretched film include linear polyester resins such as polyethylene terephthalate and polybutylene terephthalate, polyethylene, polypropylene and the like. Polyolefin resin, polyvinyl chloride resin, etc., but a linear polyester resin, particularly polyethylene terephthalate, is preferable in terms of mechanical strength, dimensional stability and the like. The thickness of the resin film is usually about 50 to 150 μm.

Further, a metal deposited layer can be used as the metal layer constituting the conductive support. Examples of the metal of the metal deposited layer include copper, nickel, zinc, and aluminum, with aluminum being preferred. . The thickness of the metal vapor deposition layer is usually about 400 to 1000 °, and the metal is vapor-deposited on the resin film by a known vapor deposition method such as an electrothermal melting deposition method, an ion beam deposition method, or an ion plating method. You. In addition, as the metal layer, a metal foil such as an aluminum foil and a nickel foil, or a laminated film in which these metals are laminated can be used. In this case, the metal foil is preferably 5 μm or less.

A known barrier layer, which is usually used, can be provided between the conductive support and the photosensitive layer.
As the barrier layer, for example, polyvinyl alcohol,
An organic layer such as casein, polyvinylpyrrolidone, polyacrylic acid, celluloses, gelatin, starch, polyurethane, polyimide and polyamide is used, and if necessary, inorganic particles such as titanium oxide and aluminum oxide may be added.

The photoreceptor layer may be a single layer containing a charge generating substance and a charge transporting substance, or may be a function separating type in which a charge generating layer and a charge transporting layer are laminated. Regarding the function-separated type photoreceptor, as the charge generating substance used for the charge generating layer, any of known charge generating substances can be used, and phthalocyanine, azo dye, quinacridone, polycyclic quinone, pyrylium salt, thiapyrylium salt, indigo , Thioindigo, anthantrone, pyranthrone,
Examples include various organic pigments such as cyanine, dyes, and the like. Among them, metals such as metal-free phthalocyanine, copper indium chloride, gallium chloride, tin, oxytitanium, zinc, and vanadium, oxides thereof, and phthalocyanines to which a chloride is coordinated are preferable.

As the binder for the charge generation layer, resins such as polyacetal such as polyvinyl butyral, polyvinyl acetate, and phenoxy resin can be used. The thickness of the charge generation layer is usually 0.1 μm to 1 μm, preferably 0.15 μm to 0.6 μm. The content of the charge generating substance used here is in the range of 20 to 300 parts by weight, preferably 50 to 200 parts by weight, based on 100 parts by weight of the binder resin.

As the charge transporting material in the charge transporting layer, various low molecular compounds such as pyrazoline derivatives, oxazole derivatives, hydrazone derivatives, stilbene derivatives, and arylamines can be used. A binder resin is blended with these charge transport materials. Preferred binder resins include, for example, polymethyl methacrylate, polystyrene, vinyl polymers such as polyvinyl chloride, and copolymers thereof, polycarbonate, polyester, polysulfone, polyether, polyketone, phenoxy, epoxy, silicone resin, and the like. These partially crosslinked cured products are also used.

Further, the charge transport layer may contain various additives such as an antioxidant and a sensitizer. The thickness of the charge transport layer is 10 to 40 μm, preferably 10 to 30 μm. The photoreceptor sheet thus obtained is cut into a predetermined size and then joined at both ends. The joining method may be joining with an adhesive or fusion with a heat sealing bar or a fusion device with ultrasonic waves.

As will be described later, the guide ribs 3 can be joined before joining both ends of the base material 2.
When the intermediate transfer belt is used as an endless belt, the resin composition of the flexible film-shaped substrate 1 may be any of a thermoplastic resin, a thermosetting resin, or rubber.
A thermoplastic resin or a thermoplastic elastomer is desirable in terms of manufacturing cost because continuous extrusion molding is possible.

As the thermoplastic resin, polyethylene (high density, medium density, low density, linear low density), propylene ethylene block or random copolymer, rubber or latex component such as ethylene / propylene copolymer rubber, styrene -Butadiene rubber, styrene-butadiene-styrene block copolymer or its hydrogenated derivative, polybutadiene, polyisobutylene, polyamide,
Polyamide imide, polyacetal, polyarylate,
Polycarbonate, polyphenylene ether, modified polyphenylene ether, polyimide, liquid crystalline polyester, polyethylene terephthalate, polysulfone, polyethersulfone, polyphenylene sulfide,
Polybisamide triazole, polybutylene terephthalate, polyetherimide, polyetheretherketone, acryl, polyvinylidene fluoride, polyvinyl fluoride, ethylene tetrafluoroethylene copolymer, polychlorotrifluoroethylene, tetrafluoroethylene hexafluoropropylene copolymer , Tetrafluoroethylene perfluoroalkyl vinyl ether copolymer, polytetrafluoroethylene, fluororubber, alkyl acrylate copolymer, polyester ester copolymer, polyether ester copolymer, polyether amide copolymer, olefin copolymer Polymers, polyurethane copolymers, or a mixture thereof are used.

Particularly preferred resins for the intermediate transfer belt are polyvinylidene fluoride, polyvinyl fluoride, ethylene tetrafluoroethylene copolymer, polychlorotrifluoroethylene, tetrafluoroethylene hexafluoropropylene copolymer, and tetrafluoroethylene perfluoroalkyl. Fluororesins such as vinyl ether copolymers and polytetrafluoroethylene and fluororubbers are also preferred to prevent contamination from toners and the like.Also, polycarbonate, polybutylene terephthalate, polyethylene terephthalate, polyester ester copolymers, polyether esters Ester-based thermoplastic resins or thermoplastic elastomers such as copolymers are preferable because of little change in electric resistance in terms of electric resistance and stability.

Further, a conductive filler may be added to these materials to adjust the electric resistance. As the conductive filler, at least one selected from carbon black, graphite, carbon fiber, metal powder, conductive metal oxide, organic metal oxide, organic metal compound, organic metal salt, conductive polymer, or the like, or a number thereof. Those consisting of a mixture of species are preferred. Among them, carbon black is particularly preferred. As carbon black, acetylene black,
There are carbon blacks such as furnace black and channel black. It is preferable to use acetylene black having excellent dispersibility so as not to impair the appearance of the film.

The amount of carbon black varies depending on the type of carbon black. In the case of acetylene black, it is preferably 3 to 25 parts by weight based on 100 parts by weight of the thermoplastic resin, and in the case of Ketjen black, it is 1 to 10 parts by weight. Parts by weight are preferred. If it is less than the above range, the conductivity is poor, and if it is more than the above range, the appearance of the product is deteriorated and the material strength is unfavorably reduced.

[0020] The resin composition may contain various additional components to be added to the usual resin composition, as long as the object of the present invention is not hindered. Such components include antioxidants, lubricants, release agents, and the like. These intermediate transfer belt materials can be obtained by forming a flat sheet using a T-die or an annular die, cutting the flat sheet into predetermined dimensions, and joining both ends. For the joining, the means described for the endless belt-shaped photoconductor can be used.

Further, a seamless tube can be formed by forming a cylindrical shape by an internal mandrel method using an annular die and cutting the cylindrical shape into a predetermined length. The endless belt 1 is made of a flexible film-like base material 2 having a predetermined width after the annular base material 2 or the flat base material 2 is joined in an annular shape or in a flat state before joining. As shown in FIG. 1, the narrow strip is joined to the peripheral surface along the side edge to form the guide rib 3.

The material of the guide rib 3 is flexible,
There is no particular limitation as long as the material has bending resistance.
Elastomers having a hardness of 20 to 100 degrees, preferably 30 to 85 degrees according to K7215 (A type) are preferable, and specifically, neoprene rubber, urethane rubber, butyl rubber,
Silicone rubber and the like are preferred. Above all, adhesion to substrate,
Urethane rubber or silicone rubber is preferred because of its electrical insulation, environmental resistance such as moisture resistance, solvent resistance, ozone resistance and heat resistance. The silicone rubber is not particularly limited, and may be a heat vulcanization type or a low temperature curing type. The molding method may be any molding method, such as a direct casting molding method in which a mold plate having a mold cavity penetrating from front to back is applied to the back surface of the base material 2 and a material is injected into the mold cavity and molded. Alternatively, the guide ribs 3 formed in advance by a method according to the purpose such as injection molding, extrusion molding, calender molding, cast molding, or the like may be joined.

As a bonding method, a method of bonding with an adhesive, a method of bonding with a double-sided pressure-sensitive adhesive tape, or a method of fusing with an ultrasonic sealing machine or the like can be used. The endless belt 1 having the guide ribs 3 thus obtained is driven using a driving roller having a function of suppressing meandering of the endless belt 1. In the present invention, the drive roller means a roller used for rotating the endless belt, and includes not only a roller connected to a drive source but also a driven roller not connected to a drive source.

FIG. 2A shows an example of this. The driving roller 5 has a small diameter portion 7 for receiving the guide rib 3 of the endless belt 1 at both ends of a roller body 6. In the small diameter portion, a step 8 is formed at the center of the roller, and a guide wall surface 9 of the endless belt 1 is formed. Also,
The peripheral surface 10 of the small diameter portion 7, that is, the bottom surface of the rib receiving portion is formed so as to be inclined so as to have a small diameter toward the end. Preferably, as shown in FIG. 2A, the curved surface is bulged outward of the drive roller 5, that is, in the outer peripheral direction with respect to the rotation axis.

Small-diameter portion 7 for receiving guide rib 3
2A may be provided at both ends of the driving roller 5 as shown in FIG. 2A, or may be formed in a groove shape near both ends of the driving roller 5 as shown in FIG. Further, the roller main body 6 may have the same diameter as the whole as shown in FIG. 2A, or may have a curved surface whose central portion swells as shown in FIG.

Endless belt 1 using drive roller 5 of the present invention
When the endless belt 1 is shifted laterally, for example, when the endless belt 1 is shifted to the left in FIG. 2A, the guide rib 3a on the right side moves to the side of the small-diameter portion 7 where the diameter is large. The rib 3a has an increased tension, so that
A force acts in a direction of a smaller diameter, that is, a direction moving to the right in the figure.

For this reason, the pressing force between the guide rib 3 and the guide wall 9 of the roller 5 is reduced. As a result, peeling of the joint portion of the guide rib 3 is prevented, and wear is prevented. In addition, one of the plurality of driving rollers used in the driving device can be used as the driving roller of the present invention,
Further, all the rollers can be the driving rollers of the present invention.

[0028]

According to the present invention, since a driving roller having a function of suppressing the lateral displacement of the endless belt is used, a large pressing force does not act on the guide rib, and therefore, the wear of the guide rib is small, and In addition, the separation of the joining portion of the guide ribs is prevented, and the endless belt can be stably rotated for a long period of time.

[Brief description of the drawings]

FIG. 1 is a partially cutaway perspective view showing an endless belt.

FIGS. 2A and 2B are side views each showing an example of a drive roller of the present invention.

FIG. 3 is a side view showing another example of the driving roller of the present invention.

FIG. 4 is a side view showing an example of use of an endless belt-shaped electrophotographic photosensitive member.

FIG. 5 is a side view showing a usage example of the intermediate transfer belt.

FIG. 6 is a partially cutaway perspective view showing a conventional endless belt with guide ribs.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Endless belt 2 Substrate 3 Guide rib 5 Drive roller 6 Roller body 7 Small diameter part 8 Step 9 Guide wall 10 Peripheral surface of small diameter part

Claims (2)

[Claims] An endless belt driving device in which a flexible film-shaped base material is formed in an annular shape and a guide rib made of a flexible material is joined to an inner peripheral surface thereof along a side edge. An endless belt for an electrophotographic apparatus, characterized in that the endless belt for an electrophotographic apparatus has a small-diameter portion for receiving a guide rib, and is provided with a drive roller inclined so that a peripheral surface of the small-diameter portion has a small diameter in an end direction. Drive. 2. The endless belt driving device for an electrophotographic apparatus according to claim 1, wherein a peripheral surface of the small diameter portion is a curved surface bulging in an outer peripheral direction.