JP2001097521A - Endless belt and image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an endless belt improved in a service life and an image forming device using this endless belt by a method of joining meandering preventing members for preventing the meandering of the endless belt and improved in durability. SOLUTION: In this endless belt having the meandering preventing member 110 on both sides of an endless belt base material 100 in the cross direction thereof, the meandering preventing members 110 are formed into endless by joining both ends of a long-size material with each other, and positions of each joint 120 of the meandering preventing members 110 are displaced from each other in the circumferential direction of the belt base material 100.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an endless belt that can rotate while preventing meandering, and an image forming apparatus that forms an image using the endless belt.

[0002]

2. Description of the Related Art In recent years, with the spread of electrophotographic color image forming apparatuses, there has been an increasing demand for high-speed color output in addition to the demand for recording quality of color images. In order to meet this demand, several proposals have been made for image forming methods. Among them, Y (yellow) toner, M (magenta) toner,
The respective images of the (cyan) toner and the Bk (black) toner are formed on a drum-shaped image carrier, and are sequentially transferred to a transfer material conveyed by a transfer conveyance belt constituted by an endless belt by respective transfer means. ,
Finally, there is a color image forming method in which fixing is performed.

There is also a color image forming system in which the endless belt is used as an intermediate transfer member, a color image is superimposedly transferred onto a belt member, and then the image is collectively transferred to a transfer material.

As described above, in a color image apparatus using an endless belt, each color image is superimposedly transferred while a transfer material is conveyed to each image carrier, so that a color image can be obtained in one process, so that image output time is reduced. It has the advantage of being fast.

An endless belt used as an intermediate transfer belt or the like is generally supported by two or more rollers, and is driven to rotate while applying an appropriate tension. However, there is a slight error or variation in the straightness, roundness, etc. of the rollers to be supported, the parallelism of the axis of each roller, or the roundness of the endless belt itself. Meandering from side to side is inevitable.

However, when the endless belt is used for an intermediate transfer belt or a transfer belt of a full-color electrophotographic apparatus or the like, since the belt meanders to the left and right, the image forming position of each color is shifted at the time of color superimposition on the belt. , Causing color misregistration.

In order to prevent such meandering, various proposals have been made to provide a meandering preventing member on the inner peripheral surface of the endless belt over the entire circumference. That is, using an endless belt provided with a groove that fits in the cross-sectional shape of the meandering prevention member over the entire circumference on the outer circumference, and a meandering prevention member provided over the entire circumference on the inner circumference,
A method in which the meandering preventing member is rotated while fitted in the groove of the roller. In addition, a roller having a length substantially equal to the distance between the insides of the meandering preventing members provided at both ends in the width direction of the belt is used, and the belt is suspended around this roller. A method of rotating while fitting. In addition, there is a method in which the endless belt runs smoothly without meandering by using a roller provided with a stepped portion at the axial end where the meandering prevention member of the belt fits.

By employing these methods, it is possible to prevent the endless belt from meandering and to form a good image without color shift.

[0009]

However, the conventional endless belt to which the meandering preventing member is attached has the following problems.

(1) The meandering preventing member is usually made of a string-shaped rubber or the like having a rectangular cross section with an adhesive tape attached to one side surface thereof. Adhered to the entire circumference and joined to each other at both ends. When the belt provided with the meandering prevention member is supported on a roller or the like and is continuously rotated, stress is easily applied to the seam of the meandering prevention member, and the belt tends to crack from this portion, and By setting the position of the seam of the meandering preventing member in the belt circumferential direction at the same position at both ends in the width direction of the belt, when the belt is wound around the roller, bending stress concentrates on the seam at both ends due to buckling of the belt. Further, cracks were easily generated, and sufficient durability could not be obtained.

(2) If the seam of the meandering preventing member is located at the same position at both ends in the width direction of the belt, the seam of the meandering preventing member passes through the roller and the seam portion is restored when bending of the belt is restored. There is a possibility that image stress such as color misregistration may be caused at the seam, due to the stress that has been concentrated on the surface becoming larger as vibration.

(3) Usually, the meandering preventing member is provided in an annular shape on the inner peripheral surface of the belt, and a joint portion thereof is cut at right angles to the belt circumferential direction. When the seam is perpendicular to the belt circumferential direction, when the belt is wound around the roller, bending stress is concentrated on the seam portion with respect to the belt,
Further, cracks are likely to occur, and the life of the belt may be shortened.

(4) If the seam of the meandering preventing member is perpendicular to the circumferential direction of the belt, the seam of the meandering preventing member is caught on the end surface of the roller or the concave groove on which the belt is suspended. The end of the meandering prevention member may be peeled off, and eventually the whole meandering prevention member may be peeled off. And if the meandering prevention member peels off,
As a result, the endless belt meanders, and the meandering preventing member rides on the roller, and thus cannot function as a belt.

(5) If the seam of the meandering prevention member is perpendicular to the circumferential direction of the belt, the end of the roller is caught on the end of the seam of the meandering prevention member, and the end is gradually cut off, resulting in wear. This may cause shavings to fall and contaminate the inside of an electrophotographic apparatus or the like, which has been a problem.

(6) In order to solve the problem of the occurrence of cracks at the end of the belt, for example, in Japanese Patent Application Laid-Open No. 5-345369, a reinforcing tape is attached to both ends of the belt to prevent deformation of the end of the belt. It has been proposed to prevent cracks and improve durability.

However, even when the reinforcing tape is stuck in this way, if the joint thereof and the joint of the meandering preventing member are located at the same position, stress is more likely to concentrate, and cracks tend to occur from this portion. Therefore, sufficient improvement in durability could not be achieved.

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and has as its object to realize a long life by a meandering preventing member joining method with improved durability while preventing meandering of an endless belt. And an image forming apparatus using the same.

[0018]

A typical configuration according to the present invention for achieving the above object is an endless belt having meandering preventing members on both sides in the width direction of an endless belt base. The member is formed in an endless shape by joining both ends of the long member to each other, and the seam position of each meandering preventing member is shifted in a circumferential direction of the belt base.

In the above structure, the occurrence of cracks in the belt base and the peeling of the seam preventing member at the seam are suppressed, and the durability is improved.

[0020]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, an embodiment of an endless belt according to the present invention and an image forming apparatus using the same will be described with reference to the drawings.

{Overall Configuration of Image Forming Apparatus} First, an image forming apparatus A using an endless belt as an intermediate transfer member will be briefly described. In FIG. 1, reference numeral 1 denotes a rotating drum type electrophotographic photosensitive member (hereinafter, referred to as a photosensitive drum) repeatedly used as a first image carrier, and has a predetermined peripheral speed (process speed) in a clockwise direction indicated by an arrow. Is driven to rotate.

The photosensitive drum 1 is uniformly charged to a predetermined polarity and potential by a primary charger 2 in the course of rotation, and then is subjected to image exposure by an image exposure means 3 (not shown) to form a target color image. An electrostatic latent image corresponding to a first color component image (for example, a yellow color component image) is formed and developed by the developing unit 4.

The developing means 4 has four developing devices rotatable with respect to the photosensitive drum 1, and the electrostatic latent image
(Yellow color developing device 4Y) to develop with the yellow toner Y as the first color. At this time the second to fourth
Developing devices (magenta developing device 4M, cyan developing device 4
C, each of the black color developing units 4Bk) is off and does not act on the photosensitive drum 1, and the first color yellow toner image is affected by the second to fourth developing units. I do not receive.

The intermediate transfer belt 5 as an intermediate transfer member is constituted by an endless belt described later, which is stretched over rollers 6a, 6b, 6c and rotationally driven clockwise at the same peripheral speed as the photosensitive drum 1. Have been.

Then, the first color yellow toner image formed and carried on the photosensitive drum 1 is transferred to the photosensitive drum 1.
In the process of passing through the nip portion between the intermediate transfer belt 5 and the intermediate transfer belt 5, the intermediate transfer is sequentially performed on the outer peripheral surface of the intermediate transfer belt 5 by the electric field generated by the primary transfer bias applied to the intermediate transfer belt 5 from the primary transfer roller 7. Primary transfer).

The surface of the photosensitive drum 1 after the transfer of the first color yellow toner image corresponding to the intermediate transfer belt 5 is cleaned by the cleaning device 8.

Hereinafter, similarly, the second color magenta toner image, the third color cyan toner image, and the fourth color black toner image are sequentially superimposed on the intermediate transfer belt 5 and transferred to correspond to the target color image. Thus, a combined color toner image is formed.

Reference numeral 9 denotes a secondary transfer roller, which is supported in parallel with the roller 6a and is disposed on the lower surface of the intermediate transfer belt 5 so as to be separated therefrom.

The primary transfer bias for the sequential superposition transfer of the toner images of the first to fourth colors from the photosensitive drum 1 to the intermediate transfer belt 5 has a polarity (+) opposite to that of the toner, and is applied from a bias power supply 10. You.

In the primary transfer process of the first to third color toner images from the photosensitive drum 1 to the intermediate transfer belt 5, the secondary transfer roller 9 can be separated from the intermediate transfer belt 5.

The transfer of the composite color toner image transferred onto the intermediate transfer belt 5 to the transfer material P, which is the second image carrier, is performed while the secondary transfer roller 9 is in contact with the intermediate transfer belt 5 and The transfer material P is fed from the paper feed roller 11 through the transfer material guide 12 to the contact nip between the intermediate transfer belt 5 and the secondary transfer roller 9 at a predetermined timing, and the secondary transfer bias is supplied from the power source 13. The voltage is applied to the secondary transfer roller 9.
With this secondary transfer bias, the intermediate transfer belt 5
The composite color toner image is transferred (secondarily transferred) to the transfer material P, which is the image carrier of (1). The transfer material P to which the toner image has been transferred is introduced into the fixing device 14 and is fixed by heating.

After the transfer of the image to the transfer material P, the cleaning charging member 15 is brought into contact with the intermediate transfer belt 5, and the transfer to the transfer material P is performed by applying a bias having a polarity opposite to that of the photosensitive drum 1. Instead, a charge having a polarity opposite to that of the photosensitive drum 1 is applied to the toner remaining on the intermediate transfer belt 5, and is electrostatically transferred to the photosensitive drum 1 in a nib portion with and close to the photosensitive drum 1. By doing
The intermediate transfer belt is cleaned. Reference numeral 16 denotes a bias power supply.

{Endless Belt} Next, the configuration of the endless belt used as the intermediate transfer belt 5 will be described. FIG. 2 is an explanatory view of an axial section of the endless belt.

The endless belt B according to this embodiment is
As shown in FIG. 2, a belt base made of a tubular film
Meandering prevention members 110 are provided at both ends in the width direction of the belt 100 and along the inner circumference of the belt. This prevents the belt B from meandering when the belt B is loaded into the image forming apparatus A to form an image. The meandering preventing member is formed by joining both ends of the long member to each other to form an endless shape, and 120 is a seam.

Further, reinforcing members 130 are attached along the outer circumference at both ends in the width direction of the belt base 100 to reinforce the belt members.

Here, the inventors of the present invention repeated the experiment to observe the structure of the joint of the meandering preventing member 110 in detail. As a result, the position of the seam 120 of the meandering preventing member 110 was changed in the belt rotation direction, that is, the belt circumferential direction. Direction (direction of arrow a in FIG. 2)
In the same position, the endless belt B is
a, 6b, and 6c (see FIG. 1), stress was concentrated on the seam 120 of the meandering prevention member 110 at both ends of the belt, and it was found that cracks were easily generated. By setting the position of the seam 120 of the prevention member 110 to a different position in the belt circumferential direction as shown in FIG. 2, the stress applied to the belt end can be dispersed, and the durability can be further improved. Was found.

The position of the seam 120 of each of the meandering preventing members 110 provided at both ends in the width direction of the belt base 100 is not particularly limited as long as it is different in the belt circumferential direction. Degree of shift (phase difference) from the end side is less than 15 ° (more than 345 ° including the reverse direction)
Even in the case of the above, a certain effect can be obtained, but the phase difference is preferably 15 ° or more (within 345 °), more preferably 90 ° or more (within 270 °), and still more preferably A greater effect can be obtained if the other seam is positioned 180 degrees from the seam (just opposite the one seam).

When the phase difference is out of the range of 15 ° or more and 345 ° or less, the seam of the meandering preventing member is too close at one end and the other end of the belt. For example, when the belt is wound around the roller, In some cases, the seam portions of the meandering prevention members on the left and right sides of the belt ride on the rollers at the same time. In this case, the same problem as when the seam of the meandering prevention member is present at the same position on the left and right of the belt occurs, and the bending stress on the belt concentrates on the seam, causing cracks and the like. Is caused.
Further, a shock at the time of passing the rollers at both ends of the joint causes a color shift at the joint, which may cause an image defect, which is not preferable.

Therefore, as described above, each joint
By shifting the position of 120, stress concentration on the seam portion of the meandering prevention member 110 is reduced, and the stress is dispersed.
Improves the durability of the belt and extends its life.

Further, by shifting the position of the seam 120 in the circumferential direction of the belt, the belt B is wound around the rollers 6a, 6b, 6c, thereby dispersing the vibration at the time of restoring, relieving the shock, and smoothing the belt B. Can be driven.

Further, if the seam 120 of the meandering preventing member 110 is perpendicular to the circumferential direction of the belt, when the belt B is wound around the rollers 6a, 6b, 6c, bending stress is applied to the belt at the seam portion. It was found that cracks were more likely to occur, and as a result of repeating the experiment, the seam 120 was inclined at an angle to the circumferential direction of the belt. I found to do.

Further, by making the seam 120 slanted, the belt B is wound around the rollers 6a, 6b, 6c, so that the shock at the time of restoring can be relieved and the belt can be driven more smoothly.

Further, it has been found that the seam 120 of the meandering preventing member 110 is more preferably inclined at least in one or both of the thickness direction and the width direction in a direction opposite to the rotation direction of the belt. It is preferable that the belt is inclined in the direction opposite to the rotation direction of the belt. However, this is not particularly limited, and the belt may be inclined in the opposite direction.

Further, as a method of connecting obliquely, it may be inclined in the thickness direction as shown in FIG. 3A or may be inclined in the width direction as shown in FIG. 3B. Further, as shown in FIG. 3 (c), it may be inclined in both the thickness and width directions.

It is preferable that one end face of the meandering prevention member 110 in the seam 120 and the other end face are parallel.

Further, in order to further improve the durability, the experiment was repeated, and it was found that it is preferable to provide the reinforcing members 130 at both ends of the belt over the entire circumference. But,
If the seam is located at the same position as the seam preventing member, the stress will also concentrate there, and the durability will be reduced. Therefore, the seam position of the reinforcing member 130 and the seam of the meander preventing member 110 will be reduced. It has been found that by shifting the position, the stress can be dispersed and the durability can be further improved. Further, by shifting the position of the joint of the reinforcing member 130 and the position of the joint of the meandering preventing member 110, an effect of reducing a shock at the time of passing through the roller is also produced.

The position of the joint of the reinforcing member 130 and the meandering preventing member 1
The position of the tenth seam is not particularly limited as long as the position is different in the belt circumferential direction, but the phase difference between one end and the other end of the belt B is less than 15 ° (exceeds 345 ° including the reverse direction). In this case, the effect can be obtained. However, it is preferable that the phase difference be set to 15 ° or more (within 345 °) to obtain a larger effect.

The reinforcing member 130 is provided over the entire circumference in the belt circumferential direction. If one end and the other end of the reinforcing member 130 do not engage with each other and there is a gap, a sufficient reinforcing effect cannot be obtained. And have a structure in which the ends are overlapped with each other.

Although the reinforcing member 130 is provided on the outer peripheral surface side of the tubular film in FIG. 2, it may be provided on the inner peripheral surface side, or may be provided on both surfaces.

Further, for the purpose of further reinforcing the seam 120 of the meandering preventing member 110, a reinforcing tape or the like is further stuck thereon, or a joint between one end and the other end of the long meandering preventing member 110 is formed. The contact surface may be bonded using an adhesive or the like.

The position where the meandering prevention member 110 is attached to the belt base 100 is usually at the end green portion of the belt base 100, but the meandering prevention member may be provided near the center of the belt base 100.

In FIG. 2, the meandering preventing member 110 is provided at a portion inside the end of the belt base 100. However, the meandering preventing member 110 can be provided at a surface position of the end of the belt base 100. Normally, the meandering prevention member 110 can be attached so as to protrude from the end of the belt base 100. However, in some cases, the meandering prevention member 110 is provided on the inner peripheral surface side of the belt base 100. Needless to say, it may be provided on the side.

The meandering preventing member 110 may be provided on the reinforcing member 130 or directly on the belt base 100 which is a tubular film without the reinforcing member 130.

As described above, the meandering preventing member in the present invention is provided on the edge of the belt base 100 in a ring shape.

Next, the meandering preventing member 110 will be described in detail. Examples of the material of the meandering prevention member 110 include a material having a certain degree of flexibility. If the endless belt is too hard, when the endless belt is wound around a roller on which the endless belt is stretched, the meandering prevention member 110 does not follow the bending of the endless belt, and the endless belt is not used. Hindered driving,
Not preferred. Conversely, if the endless belt is too soft, the meandering prevention member 110 easily rides on the rollers when a biasing force is applied to the endless belt, and the effect of preventing meandering is undesirably weak.

Generally, the meandering preventing member 110 is formed of synthetic rubber. Examples of the type of the synthetic rubber include, but are not limited to, ethylene propylene rubber, chloroprene rubber, urethane rubber, fluorine rubber, and silicone rubber.

The sectional shape may be any shape as long as it can prevent meandering of the endless belt, and various shapes such as a square, a rectangle, a trapezoid, a semicircle, and a triangle may be mentioned. The shape is not limited to this, and any cross-sectional shape can be selected as long as the shape can prevent meandering. Generally, a square or rectangular cross section is used for reasons such as ease of processing and cost.

As a method of manufacturing the meandering preventing member, first,
Molding synthetic rubber as a material into a sheet of a predetermined thickness,
An adhesive (including an adhesive) or the like is applied on one side, and if necessary, a release paper is further adhered thereon.

The adhesion of the meandering prevention member is performed by providing an adhesive (including an adhesive) on one surface of the meandering prevention member as described above. In consideration of the uniformity of the thickness and the like, a rubber sheet having a predetermined thickness to which a double-sided tape or the like is attached is generally used.

The types of double-sided tape include those having a substrate and those having no substrate. As the base material, specifically, metal foil (aluminum, nickel, copper, lead, etc.), polyester resin (PET, PEN, etc.), polyamide resin, polyimide resin, fluororesin, polyolefin resin (PP, PE, etc.), Examples include, but are not limited to, films or meshes made of polyetherimide resin (PEI), polycarbonate resin, vinyl chloride, polyurethane, rubber, and the like, and tapes made of glass cloth, nonwoven fabric, woven fabric, paper, and the like. Instead, two or more of the above materials and other materials may be used in combination.

As the material of the adhesive (including the adhesive),
Rubber-based (silicone-based), acrylic-based, and the like can be given.

Next, as described above, a rubber sheet provided with an adhesive (including an adhesive) or a double-sided tape on one surface is cut and processed into a strip shape so as to have a desired cross-sectional shape. Then, if necessary, it is cut to a length that matches the inner or outer peripheral length of the belt base. Thus, a meandering preventing member for an endless belt having a desired cross-sectional shape is obtained.

As another manufacturing method of the meandering preventing member, a thermoplastic resin, a thermoplastic elastomer, rubber or the like is extruded from an extruder having a die designed in advance to obtain a desired cross-sectional shape, and is continuously formed. A meandering prevention member may be formed on the surface and an adhesive (including an adhesive) or a double-sided tape provided on one surface may be used.

More specifically, the meandering preventing member has a width of 1 to 10 m.
m and a thickness of about 0.3 to 5 mm are preferred, but are not limited to this range. The above values are only specific examples, and are not limited to this range.

When the width of the meandering preventing member is too small or the thickness is small, a sufficient meandering preventing effect cannot be obtained. Conversely, if the meandering prevention member is too wide, not only does the area of the portion functioning as a belt be reduced, but also the size of the device incorporating and using the belt is increased. Also,
When the thickness of the meandering preventing member is large, the difference between the inner peripheral length of the belt base and the inner circumferential length of the meandering preventing member increases, and the endless belt is stretched when the endless belt is actually used. When the endless belt is wound around the roller, the meandering prevention member does not follow the bending of the endless belt, which hinders the running of the belt, which is not preferable.

The reinforcing member is to be adhered over the entire periphery of the end of the tubular film. As the material of the reinforcing member, a material having a certain strength for reinforcing the belt base is required. Specifically, a metal foil (aluminum, nickel, copper, lead, etc.), a polyester resin ( PET, PEN, etc.) Polyamide resin, Polyimide resin, Fluorine resin, Polyolefin resin (PP, PE, etc.), Polyphenylene sulfide resin (PPS), Polyetherimide resin (PEI) etc. film or mesh, Glass cloth Examples thereof include tapes made of nonwoven fabric, woven fabric, paper, and the like, but are not limited thereto. Further, two or more of the above materials and other materials may be used in combination.

The above-mentioned reinforcing tape is adhered by providing an adhesive (including an adhesive) on one side of the reinforcing tape. The work is simple and the thickness of the adhesive (including the adhesive) is uniform. In consideration of such factors, an adhesive (including an adhesive) must be applied to one side in advance.
It is a general practice to use a thin film tape having the following characteristics and wound in a roll shape. Examples of the material of the adhesive (including the adhesive) include rubber (silicone) and acrylic.

The thickness and width of the reinforcing tape are not particularly limited, but are preferably about 10 to 300 μm and about 3 to 30 mm in width. However, it is not particularly limited to the above range.

If the thickness is less than 10 μm, sufficient strength to reinforce the end portion of the belt base cannot be obtained, and the durability is inferior. Is not preferable because a step is generated between them.

If the width of the reinforcing tape is 3 mm or less, sufficient strength cannot be obtained, and if the width is 30 mm or more, the area of a portion functioning as an endless belt becomes narrow. It is preferable that the reinforcement of the end portion of the base is minimized within a sufficient range.

As the reinforcing tape, a tape having a function such as conductivity or light reflection, or a tape having two or more layers may be used as necessary.

Further, the belt base to which the reinforcing member is attached refers to a flexible tubular member, and a belt-shaped member such as a film-shaped member or a mesh-shaped member. It is not limited at all. It also includes seamless belts and seamless belts. Examples of the material of the belt base include, but are not limited to, those made of various materials such as thermosetting resin, thermoplastic resin, metal and rubber. Easy to mold,
From the viewpoint of cost and the like, a belt base made of a thermoplastic resin is preferable. Specifically, polyethylene (high density, medium density, low density, linear low density, etc.), polypropylene, polystyrene, ethylene-vinyl alcohol copolymer (EVO
H), polycarbonate, polyamide, polyacetal, polyarylate, polyphenylene ether, modified polyphenylene ether, polyimide, liquid crystal polymer,
Polysulfone, polyethersulfone, polyphenylene sulfite, polypisamide triazole, polyetherimide, polyamideimide, polyetheretherketone, aliphatic polyketone, polymethylpentene,
Polybutylene terephthalate, polyethylene terephthalate, polyethylene naphthalate, polyvinyl fluoride,
Polyvinylidene fluoride, chlorotrifluoroethylene,
One or two or more selected from hexafluoropropylene, perfluoroalkyl vinyl ether copolymer, methacrylic resin, and other various copolymers can be used.

Various conductive agents may be added for the purpose of imparting conductivity to these resins. For example, acetylene black, furnace black, carbon black such as channel black, titanium oxide, potassium titanate,
Examples include tin oxide, lithium salts, sodium salts, and quaternary ammonium salts.

Further, any additives may be added without any problem. Specific examples include fillers such as talc, mica, and calcium carbonate; flame retardants such as magnesium hydroxide and antimony trioxide; and antioxidants (phenol-based, sulfur-based, and the like). Of course, the additives are not limited to the above substances, and any other additives can be used.

As a method for adding the above-mentioned additives to the above-mentioned resin if desired, after pre-mixing, kneading is performed using a known kneading machine such as a single-screw extruder, a twin-screw extruder, a Banbury mixer, a roll, and a kneader. Method. Normally, each component is kneaded with an extruder or the like to form a compound in the form of pellets, and then molded.However, in special cases, each component is directly supplied to the molding machine and the composition is kneaded with the molding machine. It can also be formed while molding.

Further, as a method for producing such a belt substrate, known methods such as a centrifugal molding method, a continuous melt extrusion molding method, an injection molding method, a blow molding method, and an inflation film molding method can be employed. A desirable manufacturing method is a blown film forming method.

The belt base thus formed is
Operations such as stretching may be performed. The thickness of the belt base is 50
The thickness is preferably from 1000 to 1,000 μm, more preferably from 100 to 700 μm. When the thickness of the belt base is less than 50 μm, the belt is easily stretched, and when the thickness exceeds 1000 μm, it becomes difficult to deform flexibly. That's why.

The belt base may be composed of a single layer or a plurality of layers. When obtaining a belt base composed of a plurality of layers, a thermoplastic resin member previously formed of a plurality of layers may be obtained by extrusion from a multilayer die, or a single-layer tubular film may be formed from a single-layer thermoplastic resin member. After that, a new layer may be provided on the front or back surface of the single-layer belt substrate (for example, spraying or dipping of paint or the like) to form a belt substrate having a plurality of layers.

{Other Embodiments of Image Forming Apparatus} In the above-described embodiment, an image forming apparatus using an endless belt as an intermediate transfer member is illustrated. However, as shown in FIG. It is also preferably used in an image forming apparatus used as a transfer belt for conveyance.

The color image forming apparatus C shown in FIG. 4 is a color image forming apparatus of a color separation image superimposing transfer system, in which toner images of different colors are formed on a plurality of photoconductors, respectively. The toner image on each photoconductor is transferred by adjusting the position to one transfer material conveyed in contact, and a full-color image is obtained.

This will be briefly described below.
In the upper part of the inside, four image forming units are arranged side by side as electrophotographic process means, and each image forming unit is a photosensitive drum 21 (21Y, 21M, 21C, 21Bk) as an image carrier and a primary charger. Primary charging roller 22 (22Y, 22M, 22
C, 22Bk), exposure unit 23 (23Y, 23M, 23C, 23B)
k), a developing unit 24 (24Y, 24M, 24C, 24Bk) and a cleaner 25 (25Y, 25M, 25C, 25Bk). The developing units 24Y, 24M, 24C and 24Bk have yellow (Y), mass center (M), non-an (C),
Black (Bk) toner is stored.

A transfer device is provided below the image forming section.
The transfer device 26 includes a transfer roller 30 that is an endless belt stretched between a driving roller 27, a driven roller 28, and a tension roller 29, and a photosensitive drum 21Y of each image forming unit. It is configured to include a transfer charger 31 arranged to face each of 21M, 21C, and 21Bk.

At the bottom of the main body of the apparatus, there is provided a cassette 32 in which a plurality of transfer materials P are stacked and accommodated as a recording medium. The sheet is sent out one by one, and is conveyed to a registration roller 35 via a conveyance guide.

A separation charger 36 and a fixing device 37 are provided on the downstream side in the transport direction of the transfer material P, and a paper discharge tray 38 is mounted outside the apparatus main body.

In each image forming section, the photosensitive drum 21 is driven to rotate at a predetermined speed in the direction of the arrow shown in the figure.
These are uniformly charged by the primary charging roller 22, respectively. Each photosensitive drum thus charged
When exposure corresponding to image information is performed on the exposure unit 21 by the exposure unit 23, an electrostatic latent image is formed on each photosensitive drum 21.
Each electrostatic latent image is developed by each developing device 24 and visualized as a yellow toner image, a magenta toner image, a cyan toner image, and a black toner image.

On the other hand, as described above, the transfer material P conveyed from the cassette 32 to the registration roller 35 via the conveyance guide 34
Is transferred to the transfer device 26 at a timing adjusted by the registration roller 35, and the transfer belt 30 of the transfer device 26 is
The transfer material P is adsorbed on the transfer material P and passes through each image forming section. In the process, a yellow toner image, a magenta toner image, a cyan toner image, and a black toner image are superimposed on the transfer material P by the action of the transfer charger 31. Is transcribed.

The transfer material P to which the respective color toner images have been transferred as described above is discharged by the separation charger 36 and separated from the transfer belt 30, and then conveyed to the fixing device 37 to be transferred to the color toner image. And is finally discharged from the apparatus main body and stacked on the paper discharge tray 38.

Even in such an image forming apparatus, the meandering of the transfer belt causes an image shift, and it is preferable to use the endless belt having the meandering preventing member as described above in order to prevent this.

[0089]

Next, the present invention will be described in detail with reference to examples. The “parts” in the examples are parts by weight.

(Example 1) A compound (raw material for molding) having the following composition was prepared by a twin-screw extruder.

<Formulation>

100 parts by weight of polycarbonate resin 15 parts by weight of carbon black 0.5 parts by weight of antioxidant

The above mixture was kneaded with a biaxial extrusion kneader, and additives such as carbon black were sufficiently and uniformly dispersed in a binder to obtain a raw material for molding. In addition,
A kneaded product having a particle size of 2 mm was obtained. Next, the kneaded material was put into a hopper of a single-screw extruder, and a set temperature was adjusted in a range of 270 to 290 ° C. to extrude the mixture to obtain a melt. The melt is subsequently 150 mm in diameter and 1000 mm in die gap width.
It was led to a cylindrical single-layer extrusion die of μm.

Then, air was blown in from the air introduction passage to expand and expand, so that the final shape and dimensions were 160 mm in diameter and 150 μm in wall thickness. Further, the belt was cut at a width of 230 mm to obtain a belt base.

As a meandering preventing member, a thickness of 1.5 mm and a width of 4 mm
On one surface of urethane rubber having a rectangular cross-sectional shape, using a meandering prevention member to which a double-sided tape (thickness: 150 μm) having a nonwoven fabric as a base material and an acrylic pressure-sensitive adhesive is attached in advance, At both ends in the width direction of the belt, the position of the seam of the meandering prevention member was shifted by approximately 180 ° in the belt rotation direction, and the belt was stuck to the end of the belt. The seam of the meandering preventing member was joined by being inclined 45 ° in the width direction in the direction opposite to the belt rotation direction.

This belt was attached to the full-color electrophotographic apparatus shown in FIG. 1 as an intermediate transfer belt, and 50,000 full-color images were continuously printed. Even after printing 50,000 sheets, no cracks or chips were found at the belt end, and the belt had sufficient durability.

No peeling or the like was observed at the seam of the meandering prevention member.
It was still at a sufficiently usable level.

Example 2 A belt base was obtained in the same manner as in Example 1.

As a meandering preventing member, a thickness of 1.5 mm and a width of 4 mm
On one surface of urethane rubber having a rectangular cross-sectional shape, using a meandering prevention member to which a double-sided tape (thickness: 150 μm) having a nonwoven fabric as a base material and an acrylic pressure-sensitive adhesive is attached in advance, At both ends in the width direction of the belt, the position of the seam of the meandering prevention member was shifted by approximately 90 ° in the belt rotation direction, and the belt was stuck to the belt end. The seam of the meandering preventing member was joined by being inclined by 30 ° in the thickness direction in the direction opposite to the belt rotation direction.

This belt was actually attached to a full-color printer as an intermediate transfer belt in the same manner as in Example 1, and a durability test was performed. As a result, even if 50,000 sheets were printed, cracks or chips were found at the belt end. No such problems were confirmed, and it had sufficient durability.

(Example 3) 1
A kneaded product having a particle size of about 2 mm was obtained.

Next, the kneaded material was put into a hopper of a single-screw extruder, and extruded by adjusting a set temperature to a range of 270 to 290 ° C. to obtain a melt. The melt was subsequently led to a cylindrical monolayer extrusion die having a diameter of 200 mm and a die gap width of 1000 μm. Then, air was blown in from the gas introduction path to expand and expand to have a final shape and dimensions of 350 mm in diameter and 150 μm in wall thickness. Furthermore, belt width 310m
m to obtain a belt substrate.

As a meandering preventing member, a thickness of 1.5 mm and a width of 4 mm
On one side of a urethane rubber having a cross-sectional shape, a non-woven fabric is used in advance as a base material, and a double-sided tape (thickness: 150 μm) provided with an acrylic adhesive is attached. At both ends in the width direction, the position of the seam of the meandering prevention member was shifted by approximately 180 ° in the belt rotation direction, and the seam was attached to the belt end. The seam of the meandering preventing member was joined by being inclined 45 ° in the width direction in the direction opposite to the belt rotation direction.

Further, a reinforcing tape (total thickness: 50 μm, width: 18 mm) in which an acrylic adhesive was previously provided on a film (thickness: 25 μm) made of polyester resin as a reinforcing member was provided at both ends of the outer peripheral surface of the belt base. ). The seam of the reinforcing member was overlapped at the same position on the left and right, but at a position different from the seam of the meandering preventing member.

This belt was mounted on a full-color electrophotographic apparatus shown in FIG. 4 as a transfer belt, and 50,000 full-color images were continuously printed.

The obtained image was a beautiful image with almost no color shift. Even when 50,000 sheets were printed, no crack or chipping was observed at the end of the belt, and the belt had sufficient durability.

Comparative Example 1 A belt base was obtained in the same manner as in Example 1.

As a meandering preventing member, a thickness of 1.5 mm and a width of 4 mm
On one side of a urethane rubber having a cross-sectional shape, a non-woven fabric is used in advance as a base material, and a double-sided tape (thickness: 150 μm) provided with an acrylic adhesive is attached. At both ends, the position of the seam of the meandering prevention member was set to the same position in the belt rotation direction, and affixed to the belt end. The seam of the meandering preventing member was joined at right angles to the belt rotation direction.

This belt was mounted on the full-color electrophotographic apparatus shown in FIG. 1 as an intermediate transfer belt, and a durability test was carried out. As a result, from the time when 2,000 sheets were printed, the belt end of the seam preventing member was joined. Cracks occurred in the portion, and the cracks grew and reached the image forming area, affecting the image. In addition, a color shift caused by the seam of the meandering preventing member occurred from the beginning.

Comparative Example 2 A belt base was obtained in the same manner as in Example 3.

As a meandering preventing member, thickness 1.5 mm, width 4 mm
Using a meandering prevention member having a double-sided tape (thickness: 150 μm) having a nonwoven fabric as a base material and an acrylic pressure-sensitive adhesive in advance on one surface of urethane rubber having a cross-sectional shape of At both ends of the belt, the seam of the meandering preventing member was positioned at the same position in the belt rotation direction, and was adhered to the belt end. The seam of the meandering preventing member was joined at right angles to the belt rotation direction.

This belt was mounted on a full-color electrophotographic apparatus shown in FIG. 4 as a transfer belt, and a durability test was carried out. As a result, a color shift caused by a seam of the meandering preventing member occurred from the beginning. Also, around the time when 2,000 sheets were printed, cracks occurred at the belt end portion at the seam portion of the meandering preventing member, and the cracks grew and reached the image forming area, affecting the image.

In the above embodiment, the case where the endless belt obtained according to the present invention is mounted on a full-color electrophotographic apparatus as an intermediate transfer belt or a transfer belt and image evaluation is performed has been described. The application of the endless belt is not limited to these, and the endless belt can be used as an intermediate transfer belt for an electrophotographic apparatus having a plurality of photoconductors or a photoconductor belt for an electrophotographic apparatus. It is also suitably used for belts for transport, charging, developing, and the like.

[0114]

The present invention is constructed as described above.
The occurrence of cracks in the belt base and the separation of the seam of the meandering preventing member are suppressed, and the durability is improved.

Therefore, when the endless belt according to the present invention is used in an image forming apparatus, it is possible to provide an apparatus which is less likely to cause image shift and has excellent durability.

[Brief description of the drawings]

FIG. 1 is a schematic diagram illustrating a color image forming apparatus.

FIG. 2 is an explanatory axial sectional view of an endless belt.

FIG. 3 is an explanatory view of a seam of a meandering prevention member.

FIG. 4 is an explanatory diagram of another embodiment of the color image forming apparatus.

[Explanation of symbols]

 A: Image forming apparatus B: Endless belt P: Transfer material 1: Photoreceptor drum 2: Primary charger 3: Image exposure means 4: Developing means 4Bk: Black developing device 4C: Cyan developing device 4M: Magenta developing device 4Y: yellow developing device 5: intermediate transfer belt 6a, 6b, 6c: roller 7: primary transfer roller 8: cleaning device 9: secondary transfer roller 10: bias power supply 11: paper feed roller 12: transfer material guide 13: power supply 14 fixing device 15 charging member 16 bias power supply 21 photosensitive drum 22 primary charging roller 23 exposure unit 24 developing device 25 cleaner 26 transfer device 27 driving roller 28 driven roller 29 tension roller 30 … Transfer belt 31… Transfer charger 32… Cassette 33… Paper roller 34… Transport guide 35… Register roller 36… Separation charger 37… Fixer 38… Discharge tray 100 ... belt substrate 110 ... meandering prevention member 120 ... seam 130 ... reinforcing member

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Akira Shimada 3-30-2 Shimomaruko, Ota-ku, Tokyo Inside Canon Inc. (72) Inventor Akihiko Nakazawa 3-30-2 Shimomaruko, Ota-ku, Tokyo Inside (72) Inventor Atsushi Tanaka 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc. (72) Inventor Takashi Kusaba 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc. F Term (reference) 2H032 AA15 BA09 BA18 3F023 AA05 BA01 BA10 BB01 BC01 GA01 3F049 BA03 BB11 LA04 LB03

Claims (7)

[Claims] 1. An endless belt having meandering prevention members on both sides in the width direction of an endless belt base, wherein each of the meandering prevention members is formed in an endless shape by joining both ends of a long member to each other, An endless belt wherein the seam positions of the meandering preventing members are shifted in a circumferential direction of the belt base. 2. The endless belt according to claim 1, wherein a deviation of a seam position of each of the meandering preventing members is in a range of 15 ° or more and 345 ° or less in a circumferential direction of the belt base. 3. A seam of each of the meandering preventing members,
2. The endless belt according to claim 1, wherein the belt is joined obliquely in a circumferential direction of the belt base. 4. The seam of each meandering prevention member,
2. The endless belt according to claim 1, wherein at least one of the thickness direction and the width direction of the belt base is inclined in a direction opposite to a belt rotation direction. 3. 5. An endless reinforcing member formed by joining both ends of a long member to each other is provided on both sides in the width direction of the belt base, and a joint position of each reinforcing member is
The endless belt according to claim 1, wherein the endless belt is shifted from a seam position of the meandering prevention member. 6. An endless belt according to claim 1, wherein the image forming apparatus records on the recording medium conveyed by the conveying means by the image forming means. An image forming apparatus comprising: 7. An image forming apparatus for transferring an image to an intermediate transfer body and transferring the image transferred to the intermediate transfer body to a recording medium, wherein the intermediate transfer body is any one of claims 1 to 5. An image forming apparatus comprising the endless belt described in the above.