JP2000075730A - Driver of endless belt for electrophotographic device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a driver for an electrophotographic device, preventing the separation of the joint of a guide rib by correcting the transverse sway of an endless belt by means of a driving roller, and capable of stably driving the belt over a long period. SOLUTION: In a driver of an endless belt 1 comprising a flexible filmlike base material formed in an annular shape and a guide rib 3 made from a flexible material and bonded along the side edge of the inner peripheral surface thereof, a driving roller 5 having a mechanism for detecting the transverse sway of the endless belt 1 and for tilting its own rotation axis is retained; that is, when the endless belt 1 is rotated and run using the driving roller 5, meandering of the endless belt 1 occurs, and in the event of the transverse sway of the endless belt 1 to the left, a roller main body 6 is also deviated to the left along with the endless belt 1. When the roller main body 6 is deviated to the left, a bearing 8a moves along a roller support shaft 7a while a bearing 8b moves along a roller support shaft 7b, causing the roller main body 6 to fall at the right side and rise at the left side. As a result, the roller main body 6 is tilted in the take-over direction of the endless belt 1 as shown by the two- dot chain line in (B).

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 the electrophotographic apparatus, an intermediate transfer belt 30 is used. As shown in FIG. 5, the intermediate transfer belt 30 temporarily transfers an image developed by the developing device 23 onto the photosensitive drum 20a onto the intermediate transfer belt 30 and transfers the image to the paper 26 again.

Thus, an endless belt-shaped electrophotographic photosensitive member 2
The zero or intermediate transfer belt 30 has a problem that a meandering is likely to occur due to the application of a lateral force during running. For this reason, as shown in FIG. 6, the endless belt-shaped photoconductor 20 and the like form a rib 31 for guiding by joining a rib material made of a rubber-like flexible material along a side edge of the back surface thereof. Rib 31
Is fitted into the groove 33 of the roller 32 to cause the roller 32 to run, thereby preventing meandering.

However, when the lateral movement of the endless belt-shaped photosensitive member 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. Since the stress is concentrated on the root portion on the side in contact with the side wall surface of the guide rib 31, there is a problem that the bonding of the guide rib 31 is separated from that portion.

[0005]

SUMMARY OF THE INVENTION According to the present invention, an endless belt is corrected by a driving roller to prevent separation of a joining portion of a guide rib, and an electronic device capable of driving stably for a long period of time. A driving device for a photographic device is provided.

[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 an inner peripheral surface thereof is formed along a side edge. An endless belt driving device in which guide ribs made of a flexible material are joined to each other, wherein a driving roller having a mechanism for detecting a lateral run-out of the endless belt and tilting its own rotation axis is held. An endless belt driving device for a device is provided.

[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 of using an electrophotographic photoreceptor as an endless belt, a conductive support is used as a flexible film-shaped substrate 2, and a photoreceptor 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. Made in. 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, any of a thermoplastic resin, a thermosetting resin, or a rubber can be used as the resin composition of the flexible film-shaped base material 2; Thermoplastic elastomers are desirable in terms of manufacturing costs because they can be continuously extruded.

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 perfluoropolymer. Alkyl vinyl ether copolymers, fluororesins such as polytetrafluoroethylene and fluororubbers are also preferred to prevent contamination from toner and the like, and polycarbonate, polybutylene terephthalate, polyethylene terephthalate, polyester ester copolymers, polyethers An ester-based thermoplastic resin or a thermoplastic elastomer such as an ester copolymer is preferable because the electric resistance value of the electric resistance is stable with little change in electric resistance.

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. The resin composition may contain various additional components to be added to a usual resin composition as long as the object of the present invention is not impaired. 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. Alternatively, 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 formed on an inner periphery of a flexible film 2 having a predetermined width in a flat state after joining the annular base material 2 or the flat base material 2 in an annular shape or before joining. As shown in FIG. 1, a narrow strip is joined to the surface along the side edge to form the guide rib 3. The material of the guide rib 3 is not particularly limited as long as it is a material having flexibility and resistance to bending.
Elastomers having a hardness of 20 to 100 degrees, preferably 30 to 85 degrees according to 7215 (A type) are preferable, and specifically, neoprene rubber, urethane rubber, butyl rubber, silicone rubber and the like are preferable.

Among them, urethane rubber or silicone rubber is preferred from the viewpoints of adhesiveness to a substrate, electric insulation, environmental resistance such as moisture resistance, solvent resistance, ozone resistance, heat resistance, and the like. 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. Or injection molding, extrusion molding,
The guide ribs 3 formed in advance by a method according to the purpose such as calendering molding and casting molding 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 by using a drive roller having a mechanism for detecting a lateral run-out of the endless belt 1 and inclining its own rotation axis.

The driving roller of the present invention means a roller having a function of rotating and driving the endless belt 1, and includes a driven roller in addition to a roller connected to a driving source. FIG.
FIG. 1A shows an example of such an endless belt, in which an endless belt 1 drives an endless belt that travels below a roller 5 from the back side of the paper surface and runs upward on the near side of the paper surface. Drive roller 5
Has roller support shafts 7a and 7b for supporting the roller body 6, the support shafts 7a and 7b are fixed to a base (not shown), and have a shape along a segment of an arc C as shown by a dashed line. ing. The arc C is an arc that bulges out on the side opposite to the direction in which the endless belt 1 is pulled. Reference numerals 8a and 8b denote bearings for supporting the roller body 6 on the roller support shafts 7a and 7b so as to be rotatable and movable in the axial direction.

The endless belt 1 is formed by using the driving roller 5.
When the endless belt 1 rotates, the meandering of the endless belt 1 occurs, and when the lateral movement occurs on the left side in the drawing, the roller body 6 also shifts to the left with the endless belt 1. When the roller body 6 shifts to the left, the bearing 8a moves along the roller support shaft 7a, and the bearing 8b moves along the roller support shaft 7b, so that the right side of the roller body 6 is lowered and the left side is raised in the figure. As a result, the roller body 6 is inclined with respect to the direction in which the endless belt 1 is taken off, as indicated by the two-dot chain line in FIG.

[0026] Therefore, the circumferential surface traveling direction of the drive roll 6 to deliver endless belt 1 is diverted e ₂ from the arrow e ₁ in the right direction. As a result, the endless belt 1 having shifted to the left moves to the right and returns to a normal position. Further, the driving roller 5 can have the structure shown in FIG.
The drive roller 5 in FIG. 3A is endless in a direction of ascending upward from the back side of the paper through the lower side of the roll body 6 to the front side of the paper as shown in the side cross section of FIG. The case where a belt runs is shown.

The roller body 5 shown in FIG. 3A has a rotating shaft 10 protruding at an end, and the rotating shaft 10 is supported by a bearing 9 of a position adjusting cam 11. The position adjusting cam 11 is a plate-like body having one side, that is, a small radius of the surface on the roller center side and a large radius of the outer surface. The outer peripheral surface is an inclined surface and is supported by the pin It is pivotally mounted on the shaft.

The support plate 13 is fixed to a frame 14 fixed to a base (not shown). In FIG. 3A,
A portion of the frame body 14 facing the roller body 6 is opened, a second bearing 16 is held via an elastic body 15, and the second bearing is displaced in a direction orthogonal to the roller rotation shaft 10. It is held so as to support the roller rotating shaft 10. The drive roller 5 shown in FIG. 3 is provided with a similar mechanism at the left end.

When the apparatus shown in FIG. 3 is used, the inner peripheral surface of the guide rib 3 of the endless belt 1 is
Preferably, an inclined surface corresponding to the inclination of the outer peripheral surface is formed. When the endless belt 1 is driven by using the apparatus shown in FIG. 3, if the endless belt 1 runs rightward in FIG. 3A, the guide ribs 3 are shifted in the large-diameter direction of the position adjustment cam 11. As a result, the tension of the endless belt 1 increases, and the contact pressure between the guide ribs 3 and the outer peripheral surface of the position adjusting cam 11 increases. As a result, the friction increases. In (B), the right part is displaced to the upper left. Due to the upward movement of the position adjusting cam 11, the rotating shaft 10 of the drive roller 5 rises, and the right side of the drive roller 5 rises upward.

On the other hand, at the left end, a similar mechanism operates in the opposite direction, and the left rotating shaft is lowered. As a result, the rotational traveling direction of the endless belt contact surface of the roll body 6 changes from e ₁ to e.
_The endless belt is converted to ₂ and sent to the left, returning to the normal position. When the endless belt 1 returns to the normal position, the guide ribs 3 move in the small-diameter direction of the position adjustment cam 11, and as a result, the friction between the guide ribs 3 and the position adjustment cam 11 decreases. The rotary shaft 10 returns to the original position by the second bearing 16.

In place of the second bearing 15 supported by the elastic body 15, a spring may be provided so that the upper part of the position adjusting cam 11 is urged rightward in FIG. 3B.

[0032]

According to the present invention, the lateral displacement of the endless belt is corrected by the inclination of the rotating shaft of the driving roller.
Since a large lateral force is not applied to the guide ribs, the guide ribs are not separated from each other, so that the driving can be stably performed for a long period of time. In addition, since the drive roller itself detects the lateral deflection of the endless belt and inclines the rotation axis, the position detection mechanism of the endless belt and the mechanism for operating the drive roll based on the mechanism are unnecessary and simplified. In addition, a practical endless belt drive roller for an electrophotographic apparatus that can be installed in a small space can be obtained.

[Brief description of the drawings]

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

2A is a longitudinal sectional view showing an example of the driving roll of the present invention, FIG. 2B is an explanatory view showing the operation thereof,

3A is a partial longitudinal sectional view showing another example of the driving roll of the present invention, FIG. 3B is a sectional view taken along line AA of FIG.

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 an example of use 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 Base material 3 Guide rib 5 Drive roller 6 Roller body 7a, 7b Roller support shaft 8a, 8b Bearing 11 Position adjustment cam 12 Pin 13 Support plate 14 Frame 15 Elastic body 16 Second bearing

Claims (4)

[Claims] An endless belt driving device in which a flexible film-shaped substrate 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 driving device for an electrophotographic apparatus, comprising: a driving roller having a mechanism for detecting a lateral runout of the image forming apparatus and tilting a rotation axis of the driving roller. 2. The endless end for an electrophotographic apparatus according to claim 1, wherein the drive roller is a roller that is loosely fitted on a roller support shaft having a shape along the arc segment so as to be displaceable in the axial direction of the roller support shaft. Belt drive. 3. A drive roller having a plate-like shape having an inclined outer peripheral surface with a large radius on one side and a small radius on the other side, and is supported by a position adjusting cam swingably supported by an eccentric shaft. A drive device for an endless belt for an electrophotographic apparatus according to claim 1. 4. The electrophotographic apparatus according to claim 3, wherein the drive roller is supported by a position adjusting cam and supported by a second bearing supported by an elastic body so as to be displaceable in a direction perpendicular to the roller axis. Endless belt drive.