JP2002018971A - Endless belt, method for manufacturing the same, molding apparatus and image forming apparatus equipped with endless belt - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an endless belt having no stepped part due to the prevention of positional shift or the like, having uniform belt thickness as a whole and having mechanical strength generating no twist or wrinkles even if meandering or the offset of the belt is generated, a method for manufacturing the same, a molding apparatus and an image forming apparatus equipped with the endless belt. SOLUTION: The endless belt has reinforcing fibers 3 on both sides thereof and has uniform thickness as a whole and manufactured by winding the reinforcing fibers 3 preliminarily immersed in a belt raw material liquid or a solvent around the small diameter part 11b of a ring 11 and utilizing centrifugal force by rotating the ring 11 to expel the reinforcing fibers 3 from the small diameter part 11b of the ring 11 to bond them to the inner surface 12a of a mold 12.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an endless belt used for an image forming apparatus such as a copying machine, a printer, a facsimile, and the like, a method of manufacturing the endless belt, and an image forming apparatus provided with the endless belt.

[0002]

2. Description of the Related Art Conventionally, in an image forming apparatus such as a copying machine, a printer, a facsimile, etc., an endless belt having no seam is a so-called intermediate transfer roller of a transfer unit as a carrier for intermediate toner in an electrostatic copying process. Also, it is used as a fixing belt for fixing toner on recording paper. This endless belt is manufactured by centrifugal molding, dipping,
It is manufactured by various manufacturing methods such as an extrusion method. For example, in a centrifugal molding method, a fluid molding material is applied to the inner peripheral surface of a cylindrical mold (mold for belt molding) by spraying or the like, and the mold is rotated at a high speed around the cylindrical central axis. As a result, the molding material is uniformly diffused by the generated centrifugal force to form a uniform film, and thereafter, the uniform film is dried and solidified and taken out, whereby a cylindrical seamless endless belt is formed.

When a cylindrical endless belt is mounted on a transfer unit and operated, if the driving rollers and the endless belt themselves have poor dimensional variations and assembling accuracy, the rotation time caused by the irregularity is not good. Due to uneven sliding or meandering of the belt, the belt position may be shifted, and the belt may be wrinkled to distort the image or break the belt. For this reason, conventionally, for example, as shown in FIG. 9, the non-stop tape 103 for preventing displacement is attached and fixed to both sides of the belt base 105 of the endless belt 116, and the displacement using the step due to the increased wall thickness is conventionally performed. Prevention had been done. Furthermore, in order to increase the fixing strength of the tape, the tape is sewn with a thread as disclosed in JP-A-9-165120.

However, it is difficult to apply the non-stop tape 103 to the belt base 105 of the endless belt 116 having elasticity and flexibility, which has already been formed and has been removed from the mold. Jigs and mass production equipment were required.

[0005] Further, according to the method of sewing the tape with a thread, the number of steps is increased and the production efficiency is deteriorated. Moreover, the fixing by this method is effective for a belt made of a material having high elasticity such as rubber, but is not suitable for a belt made of a material having low elasticity and tear strength such as plastic. In particular, materials such as polyimide and polyamideimide have excellent properties as a belt, but have low tear strength, and are not suitable for fixing a tape by a method of sewing with a thread.

Therefore, the present inventors have already proposed a method of integrally forming the non-stop tape at the time of forming the belt and a belt formed by the method. According to this method of fixing the non-stop tape by integral molding, it is possible to obtain a tape that is suitable for a belt made of a plastic material having low elasticity and tear strength.

[0007]

However, in recent years,
By increasing the elasticity of the surface of the transfer body for higher image quality, the crush of the roller and belt nip during transfer is increased,
The contact area has been secured, and for that purpose, the belt has become the mainstream of a plurality of layers in which a highly elastic material is laminated on a base.

When a belt having such a configuration is formed, a highly elastic material such as rubber is applied to the surface of the already formed belt base 105 to form a highly elastic material layer 102 on the surface. Do. At this time, coating is performed by inserting the cylindrical support 104 into the hollow inside of the hollow cylindrical belt base 105 so that the flexible belt base 105 is not bent (see FIG. 10).

However, if there is a step due to the non-stop tape 103 on both sides of the belt base 105, there is a difference in the belt inner diameter (diameter of a circle whose inner circumferential length is a circle) between the center and both sides in the belt width direction. As a result, there is a problem that the support 104 cannot be smoothly inserted. As shown in FIG.
If the outer diameter of the support 104 is adjusted to the inner diameter of both sides including the thickness of the tape 103 on both sides, a gap is generated between the outer diameter of the support 104 and the inner diameter of the belt at the center. As a result, the central portion in the belt width direction is loosened, and the belt is bent when a highly elastic material such as rubber is applied to the belt surface, or the high elastic material layer 102 such as rubber applied to the surface is applied.
Also, when heat-cured, there is a problem that the belt is deformed into a drum shape due to the curing shrinkage.

The present invention has been made in view of the above circumstances, has no step due to misalignment prevention and the like, has a uniform belt thickness as a whole, and is capable of twisting even when meandering or belt deviation occurs. It is an object to provide an endless belt having mechanical strength that does not cause wrinkles, a method for manufacturing the same, and an image forming apparatus provided with the endless belt.

[0011]

According to a first aspect of the present invention, there is provided an endless belt having a fiber extending in a circumferential direction in which a fiber direction is orthogonal to the width direction. It is characterized by having a reinforcing fiber and having a uniform thickness from one side to the other side in the width direction including the portion having the reinforcing fiber.

According to the first aspect of the present invention, since the belt has a uniform thickness as a whole, the support is smoothly formed when a highly elastic material layer such as rubber is formed on the belt surface. Can be inserted. As a result, a highly elastic material can be applied satisfactorily, and the belt is not deformed even by its curing shrinkage, so that an accurate belt can be obtained. Further, since the reinforcing fibers extending in the circumferential direction in which the fiber direction is orthogonal to the belt width direction are provided on both side portions in the belt width direction, the mechanical strength against an external force such as tearing is strong and the fiber is hardly broken. Even if a tear or the like occurs, the reinforcing fiber extending in the circumferential direction can prevent the tear from expanding in the width direction of the belt, and even if it has meandering or leaning toward the belt, it can be twisted or wrinkled. The effect of not generating can also be obtained.

According to a second aspect of the present invention, there is provided a method for producing an endless belt, comprising a reinforcing fiber extending in a circumferential direction perpendicular to the width direction on both sides in the width direction, and a portion having the reinforcing fiber. A method for producing an endless belt having a uniform thickness from one side to the other side in the width direction, including the inner surface of a hollow cylindrical molding die, after immersing a reinforcing fiber in a belt raw material liquid. After applying along the circumferential direction perpendicular to the cylindrical central axis of the mold, the belt material liquid is applied to the mold, and the belt is formed by rotating the mold around the cylindrical central axis. I do.

According to a third aspect of the present invention, there is provided a method of manufacturing an endless belt, comprising a reinforcing fiber extending in a circumferential direction in which a fiber direction is perpendicular to the width direction, and a reinforcing fiber at both sides in the width direction. A method of manufacturing an endless belt having a uniform thickness from one side to the other side in the width direction, including a hollow cylindrical mold, wherein a reinforcing fiber is immersed in a solvent on a inner surface of a hollow cylindrical mold, and then the mold is formed. After applying along the circumferential direction orthogonal to the cylindrical central axis of the above, the belt raw material liquid is applied to the forming die, and the forming die is rotated about the cylindrical central axis to form an endless belt. .

According to the second and third aspects of the present invention, since the reinforcing fibers are immersed in a liquid such as a belt raw material liquid or a solvent and then adhered to the inner surface of the molding die, the reinforcing fibers do not drop. It is possible to easily adhere and adhere to the mold without twisting or bending. Thereby, the spacing between the fibers can be arranged in an orderly manner, and even if a tear is formed in the side of the belt, the tear can be prevented from advancing in the belt width direction.

According to a fourth aspect of the present invention, there is provided a method of manufacturing an endless belt, comprising a reinforcing fiber extending in a circumferential direction in which a fiber direction is orthogonal to the width direction, on both sides in the width direction, and a portion having the reinforcing fiber. A method for producing an endless belt having a uniform thickness from one side to the other side in the width direction including the reinforcing fiber immersed in a belt raw material liquid or a solvent on an outer peripheral surface of a cylindrical member. Winding along the circumferential direction, inserting a cylindrical member from the end into a molding die for forming an endless belt, rotating the inserted cylindrical member and using centrifugal force to form a cylindrical member It is characterized in that the wound reinforcing fiber is repelled from the cylindrical member and is attached to the inner surface of the mold.

According to the fourth aspect of the present invention, the reinforcing fiber immersed in the belt material solution or the solvent is wound around the outer peripheral surface of the cylindrical member, so that the reinforcing fiber is easily twisted or bent. Can be wound. Furthermore, by rotating the cylindrical member and using centrifugal force, the reinforcing fibers are flipped off from the cylindrical member and attached to the inner surface of the molding die, so that the state in which the reinforcing fiber is automatically and orderly wound around the cylindrical member is automatically adjusted. The reinforcing fibers can be stuck to the inner surface of the molding die while securing them.

According to a fifth aspect of the present invention, in the method of manufacturing an endless belt according to the fourth aspect, the reinforcing fiber is formed by integrally rotating the cylindrical member and the mold. It is characterized in that it is attached to the inner surface of the mold. According to the fifth aspect of the present invention, since the cylindrical member and the mold are integrally rotated, the reinforcing fibers can be smoothly adhered to the inner surface of the mold.

According to a sixth aspect of the present invention, in the method of manufacturing an endless belt according to the fourth aspect, the reinforcing fibers are rotated by rotating the cylindrical member relative to the mold. It is characterized in that it is attached to the inner surface of the mold.

According to the sixth aspect of the present invention, since the columnar member is relatively rotated with respect to the molding die, it is possible to select an optimum rotation speed for each.

According to a seventh aspect of the present invention, in the method for manufacturing an endless belt according to any one of the fourth to sixth aspects, the columnar member has a large diameter portion and a small diameter portion; It is characterized in that reinforcing fibers are wound around the small diameter portion.

According to the seventh aspect of the present invention, since the cylindrical member has the large diameter portion and the small diameter portion, and the reinforcing fiber is wound around the small diameter portion, the reinforcing fiber can be easily and reliably wound. it can.

[0023] In the method for producing an endless belt according to claim 8, the reinforcing fiber extending in the circumferential direction whose fiber direction is perpendicular to the width direction is provided on both sides in the width direction, and the reinforcing fiber is provided. A method of manufacturing an endless belt having a uniform thickness from one side to the other side in the width direction including the reinforcing fiber immersed in a belt raw material liquid or a solvent on an outer peripheral surface of a cylindrical member. A winding step of winding along the circumferential direction, an inserting step of inserting a reinforcing fiber adhering member on a side of a forming die for forming an endless belt, and rotating the inserted cylindrical member to reduce centrifugal force. A bonding step in which the reinforcing fibers wound around the cylindrical member are repelled from the cylindrical member by use and are applied to the inner surface of the forming die, a coating step of applying a belt raw material liquid to the inner surface of the forming die, and forming. The method includes a rotation step of rotating a molding die so that the belt material liquid applied to the inner surface is uniformly diffused, and a curing step of curing the belt material liquid uniformly diffused on the molding die inner surface. .

According to the eighth aspect of the present invention, since reinforcing fibers are provided on both sides, mechanical strength against external force such as tearing is high, and deformation is generated because the belt thickness is uniform as a whole. It is possible to obtain an endless belt on which a high elastic material layer can be favorably formed on the surface without performing.

According to a ninth aspect of the present invention, there is provided a molding apparatus having a hollow cylindrical shape for forming a belt, and a reinforcing fiber wound around an outer peripheral surface for attaching the reinforcing fiber to an inner surface of the mold. A cylindrical member that is inserted and rotated from the end of the mold, and a rotation driving unit that rotates the cylindrical member,
Coating means for applying the belt raw material liquid to the inner surface of the molding die.

The molding apparatus according to claim 10 is the same as the molding apparatus according to claim 9.
Wherein the columnar member has a large diameter portion and a small diameter portion.

[0027] In the image forming apparatus according to the eleventh aspect, on both sides in the width direction, there are reinforcing fibers extending in the circumferential direction in which the fiber direction is orthogonal to the width direction. An endless belt having a uniform thickness from one side to the other on both sides in the width direction is provided.

[0028]

FIG. 7 is a schematic perspective view of a digital copier 109 as an image forming apparatus provided with an endless belt according to the present invention. The digital copier 109 illuminates and scans a document image therein, reads the image information, and forms an image on a recording paper 112 based on the image data sent from the reading unit. A writing unit 111.

As shown in FIG. 8, the writing section 111 generally includes a laser section 113, a photosensitive drum 114, and a toner section 1.
15, transfer roller 119, transfer belt 1, fixing roller 1
17 and a fixing belt 118. Based on the image data sent from the reading unit 110, the laser unit 113 scans and irradiates the photosensitive drum 114 with laser, and the photosensitive drum 114 is charged corresponding to the image to be formed. Toner is supplied from a toner unit 115 to the charged portion of the photoconductor drum 114, and the toner is transferred to the transfer belt 1 via the photoconductor drum 114, and is transferred from the transfer belt 1 to the recording paper 112, and is recorded. An image is formed on the paper 112. The toner transferred from the transfer belt 1 to the recording paper 112 is heated and pressed by the fixing roller 117 and the fixing belt 118, and is fixed on the recording paper 112.

The endless belt according to the present invention is used as both the transfer belt 1 and the fixing belt 118. In this embodiment, the case where the endless belt is used as the transfer belt 1 will be described.

FIG. 1 is a schematic configuration diagram of the transfer belt 1 used in the digital copying machine 109 as the image forming apparatus. The transfer belt 1 has a highly elastic material layer 2 made of rubber or the like formed on a surface of a belt base 5 formed of a plastic material such as polyimide. The transfer belt 1 has a highly elastic material layer 2 on its surface, so that the crush during nip can be increased, and a large contact area with a recording paper or a roller can be secured, so that high-precision conveyance is possible. Therefore, it is possible to contribute to higher image quality.

The thickness of the belt base 5 is a uniform thickness t1 as a whole. The thickness t2 of the high elastic material layer 2 formed on the belt surface is also uniform as a whole, and therefore, the belt thickness is the same as that of the entire belt despite having the reinforcing fibers 3 on both sides in the width direction as described later. Has a uniform thickness t = t1 + t2. In forming the highly elastic material layer 2 on the belt surface, as shown in a schematic perspective view in FIG. 2, the inside diameter of the belt is substantially equal to the inner diameter of the belt (the diameter of a circle whose inner circumference is the circumference). After inserting the cylindrical support 4 having the same outer diameter, a highly elastic material is applied to the surface of the belt base 5 and heat-cured. Here, since the thickness t1 of the belt base 5 is a uniform thickness as a whole, the inner diameter of the belt is also a uniform size as a whole belt, and the support 4 is smoothly placed without being caught by the hollow inside of the belt base 5. Can be inserted.
Further, since there is no gap between the inner diameter of the belt base 5 and the outer diameter of the support 4, the high elastic material can be satisfactorily applied without the belt base 5 being loosened. Even when the high elastic material layer 2 applied to the surface of the belt base 5 is heat-cured, there is no gap between the outer diameter of the support 4 and the inner diameter of the belt base 5. Is not deformed (see FIG. 3).

On both sides in the width direction of the transfer belt 1, reinforcing fibers 3 are disposed. A method of manufacturing the transfer belt 1 on which the reinforcing fibers 3 are disposed will be described later. However, since the reinforcing fibers 3 are disposed on both sides, the transfer belt 1 has high mechanical strength against an external force such as tearing and is broken. In addition, it does not twist or wrinkle even when it is meandering or leaning toward the belt. Since the reinforcing fibers 3 are arranged straight without twisting or bending, and the spaces between the fibers are arranged in an orderly manner, even if a crack is formed, the crack proceeds in the belt width direction. Never.

FIGS. 4 and 5 (a) to 5 (e) show an embodiment of a method of manufacturing an endless belt according to the present invention. The endless belt manufactured by this manufacturing method has the high elastic material layer 2 formed on the surface, and is used as the transfer belt 1 in the writing unit 111 of the digital copying machine 109.

In FIG. 4, reference numeral 11 denotes a ring as a columnar member. The outer diameter of the ring 11 has a large diameter portion 11 a and a large diameter portion 11 for winding the reinforcing fiber 3.
A small-diameter portion 11b having a diameter slightly smaller than a is formed in a stepped cylindrical shape, and a hollow portion 11c for inserting a coating nozzle described later is formed in the center of the column. A predetermined number of reinforcing fibers 3 having a length corresponding to the circumferential length of the small-diameter portion 11b, for example, a length corresponding to approximately one round, are wound around the step portion 11b. Since the reinforcing fibers 3 are previously immersed in a liquid belt base material (belt raw material liquid) or a solvent, the reinforcing fibers 3 can be easily wound in close contact with the small-diameter portion 11b, and can easily slide down or peel off. There is no.
Since it is wound along the small diameter portion 11b, the reinforcing fibers 5 are not twisted or bent, and can be wound with the spacing between the fibers arranged in an orderly manner. The fiber diameter of the reinforcing fiber 3 is smaller than the thickness t1 of the belt base 5, and even when the reinforcing fiber 3 is wound around the small diameter portion 11b, the outer diameter of the wound portion is larger than the outer diameter of the large diameter portion 11a. small.

After the reinforcing fiber 5 is wound around the small diameter portion 11b, the ring 11 is inserted into a forming die 12 for forming a belt as shown in FIG. Mold 1
Reference numeral 2 denotes a substantially hollow cylindrical shape, the inner diameter of which is formed to be substantially the same as the outer diameter of the large diameter portion 11a of the ring 11;
1 are fitted. Further, since the outer diameter of the portion where the reinforcing fiber 3 is wound around the small diameter portion 11b of the ring 11 is smaller than the outer diameter of the large diameter portion 11a, the reinforcing fiber 3 does not touch the inner surface 12a of the molding die 12, Ring 1
1 can be smoothly inserted into the mold 12.

After the ring 11 is set at a predetermined position, as shown in FIG. 4B, the ring 11 is rotated at a high speed about a cylindrical central axis indicated by a two-dot chain line in the figure. As a result, the reinforcing fiber 3 wound around the small diameter portion 11b is repelled from the small diameter portion 11b by the action of centrifugal force, and the molding die 1
2 (see FIGS. 5 (c) and 6). At this time, if the small-diameter portion 11b of the ring 11 has a releasing property because the ring 11 is formed of a release material or a release layer is formed on the surface of the ring 11, the reinforcing fiber is used. 3 can be more smoothly repelled from the small diameter portion 11b. Since the reinforcing fibers 3 are automatically stuck to the inner surface 12a of the mold by the action of centrifugal force,
It is stuck to the inner surface 12a with little disturbance while maintaining the orderlyness of the state wound around the small-diameter portion 11b, and is in close contact with the inner surface 12a without twisting or bending.

At this time, the ring 11 and the molding die 12
And the rotation may be synchronized and the rotation speed may be synchronized. Alternatively, the ring 11 and the molding die 12 may be rotated at different rotation speeds by giving optimum rotation speeds.

After the reinforcing fiber 3 has been stuck to the inner surface 12a, the nozzle 14
Then, as shown in FIG. 5 (d), a liquid belt base material (belt raw material) is applied to the inner surface 12 a of the molding die 12. Since the coating is performed while rotating the molding die 12, the belt raw material liquid is uniformly diffused and has a uniform thickness t1.
Is formed. At this time, the ring 11
Functions as a damming member for preventing leakage of the belt raw material liquid from the molding die 12, so that the belt raw material liquid does not leak from the molding die 12.

Here, since the fiber diameter of the reinforcing fibers 3 is smaller than the thickness t1 of the belt base 5, the thickness of the belt base 5 must be larger in the portion having the reinforcing fibers 3 than in other portions. However, it is molded as a uniform thickness t1 as a whole.

When the molding of the belt base 5 is completed, the belt base 5 is dried and heated and hardened by heating with a heater (not shown), and thereafter, the rotation of the mold 12 and the ring 11 is stopped and the ring 11 is removed (FIG. 5 (e)),
The belt base 5 is taken out of the mold 12. The formed belt base 5 has the reinforcing fibers 3 on both sides in the belt width direction, and has a uniform thickness t1 throughout the belt.

A highly elastic material is applied to the surface of the thus formed belt base 5 and cured by heating to form a highly elastic material layer 2 having a uniform thickness t2. An endless belt having the following formula is prepared and used as the transfer belt 1.

In the above embodiment, the ring 11 is used as a damming member for preventing the belt material liquid from leaking out of the molding die 12 in the step of applying the belt material liquid. After attaching the fibers 3 to the inner surface 12a of the molding die, the ring 11 may be removed, another damming member may be newly inserted from both sides of the molding die 12, and the belt material liquid may be applied.

Example 1 PBO (polybenzobis) immersed in a solvent DMAC (dimethylacetamide) was applied to the small diameter portion of a fluororesin ring having a large diameter portion having a diameter of 60 mm and a small diameter portion having a diameter of 58 mm. Oxazole) fibers.

Although the fibers were slippery, it was slippery and it was difficult to apply them. However, the wet fibers were wound tightly. Therefore, the above two rings were set at both ends inside a cylindrical coating mold (molding mold for belt molding) made of aluminum having an inner diameter of 60 mm and rotated at a high speed of 2 G or more. When the rotation was stopped and the ring was removed, the fibers stuck to the inner surface of the coating mold, and did not drop.

Therefore, a blocking member is newly inserted at both ends of the coating mold to apply a solution of the thermoplastic resin polyamideimide (solvent DMAC 30% diluent), and then the coating film is made uniform while rotating at a high speed. Drying the solvent at 80 ° C.,
After that, the rotation was stopped, the mold was taken out, and the mold was transferred to a heating furnace for 20
The solvent was completely removed by heating at 0 ° C.

After the coating film was sufficiently cured and cooled, the belt film (belt base) was taken out from the coating mold. The fibers were embedded in the films on both sides of the belt and were completely adhered to each other. It was the same as no part.

The belt membrane thus produced is wrapped with a portion including the fibers at 50 mm in the belt circumferential direction × 20 mm in the belt width direction.
The sample was cut out to a size of 5 mm, and a 5 mm cut was made with scissors so as not to cut the fiber, and the sample was pulled in the fiber direction to measure the tear strength.

When the maximum strength of the belt substrate is exceeded, the tearing of the sample starts to expand and the tension decreases, but when the tear reaches the fiber portion, the tension increases again. When the strength exceeded the peak value, it broke at once, but the maximum strength at that time was 800 kgf / cm ² (7.85 × 10 ⁷ N /
m ² ).

Example 2 A PBO fiber immersed in a polyamic acid solution (solvent DMAC 10% diluent) was wound around the same fluororesin ring as in Example 1. The solution was so small that no droplets dripped from the fibers. The wet fibers wrapped tight.

Therefore, the two rings were set on both sides inside the same aluminum cylindrical coating mold as in Example 1 and rotated at a high speed of 2 G or more.

When the rotation was stopped and the ring was removed, it was confirmed that the fibers were stuck to the inner surface of the coating mold and did not drop.

Therefore, the ring is used as a blocking member as it is, and the polyamic acid solution (solvent DM
(AC 30% diluent), and then the coating film was made uniform while rotating at high speed. After further drying the solvent at 80 ° C,
Stop the rotation, remove the mold, transfer it to the heating furnace,
The mixture was heated at ℃ to completely remove the solvent, and then heat cured at 300 ℃.

After the coating film was sufficiently cured, it was cooled and the belt film was taken out of the mold. However, the fibers were embedded in the films on both sides of the belt and were completely adhered.

The tear strength of the belt film thus produced was measured in the same manner as in Example 1.

When the maximum strength of the belt substrate is exceeded, the tearing of the sample starts to expand and the tension decreases, but when the tear reaches the fiber portion, the tension increases again. When the intensity exceeded the peak value, it was broken at a stretch, but the maximum intensity at that time was 1000 kgf / cm ² (9.81 × 10 ⁷ N /
m ² ).

COMPARATIVE EXAMPLE 1 A polyamideimide solution having the same material as in Example 1 was centrifugally applied using the same aluminum cylindrical coating type as in Example 1 to obtain a polyamideimide having no reinforcing members on both sides. An endless resin belt was formed.

The thus formed belt film was cut out to a size of 50 mm in the belt circumferential direction × 20 mm in the belt width direction to obtain a sample, a 5 mm cut was made with scissors, and the sample was pulled in the long side direction to measure the tear strength.

When the maximum strength was exceeded, the tearing of the sample began to expand, and at the same time the tension decreased. The tension continuously decreased without increasing, and became zero at a stretch when it was broken. At that time, the difference between the maximum strength and the tensile tension until breaking was 300 kgf / cm ² (2.94 × 10 ^7).
N / m ² ).

[Comparative Example 2] A polyamic acid solution of the same material as in Example 2 was centrifugally applied using the same aluminum cylindrical coating mold as in Example 1 to obtain a polyimide resin without reinforcing members on both sides. An endless belt was formed.

The thus formed belt film was cut out in a size of 50 mm in the circumferential direction of the belt and 20 mm in the width direction of the belt to obtain a sample. A 5 mm cut was made with scissors, and the sample was pulled in the long side direction to measure the tear strength.

When the maximum strength was exceeded, the tearing of the sample began to expand, and at the same time the tension decreased. The tension continuously decreased without increasing, and became zero at a stretch when it was broken. At that time, the difference between the maximum strength and the tensile tension until breaking was 300 kgf / cm ² (2.94 × 10 ^7).
N / m ² ).

[Comparative Example 3] A polyimide precursor solution as a polyamic acid (trade name: Toraynis well 3000, manufactured by Toray Industries Co., Ltd.) and carbon black as a conductive agent in a DMAC And a solution diluted to 30% in advance, the coating film was made uniform while rotating at a high speed, and the solvent was further dried at 80 ° C. Thereafter, the rotation was stopped, the mold was taken out, transferred to a thermostat, and first heated at 100 ° C. to completely remove the solvent and perform preliminary imidization.

Then, both sides of the belt are masked with a width of 5 mm, a dam is provided, a few lines of PBO fiber are adhered to an area therebetween, a polyimide precursor solution is applied, and a 0.5 mm film is dried after heating with a solvent. Was formed, and further heated at a temperature of 300 ° C. to perform complete curing.

After the coating film was sufficiently cured and cooled, and the belt film was taken out from the mold, the stopper portions laminated on both sides of the belt were completely adhered. Even if the non-stop portion was forcibly peeled off from the belt, the belt and the non-stop portion were torn in the circumferential direction but did not crack in the axial direction.

The belt membrane thus produced is applied to a portion including the fiber at a belt circumferential direction of 50 mm × a belt width direction of 20 mm.
The sample was cut out to a size of mm, and a 5 mm cut was made with scissors so as not to cut the fiber, and the fiber was pulled in the fiber direction to measure the tear strength.

When the maximum strength of the belt substrate is exceeded, the sample
The tear begins to spread and the tension decreases, but the tear
Upon reaching the fiber portion, the tension increases again. Its strength is
If it exceeds the threshold value, it will be broken at a stretch, but the maximum
Strength is 1000kgf / cm ^Two(9.81 × 10⁷N / m
^Two)Met.

[Experiment of Using Belt] Using the belts of Examples 1 and 2 and Comparative Examples 1 to 3 as bases, each was inserted outside a support, and a silicone rubber coating solution was applied by spray coating while rotating. A fixing belt was prepared by providing a rubber elastic layer of 0.5 mm and further forming a fluororesin layer of about 1 μm.

In Examples 1 and 2 and Comparative Examples 1 and 2, there was no deformation of the belt, and a good elastic laminated belt could be produced.
In Comparative Example 3, a dent was formed in the central portion, resulting in a drum shape.

These samples were mounted on a fixing belt unit of a full-color copying machine, and a heating cycle was repeated while outputting images to evaluate the durability of the belt.

The belt of Comparative Example 3 was difficult to be attached to the unit, and if it was forcibly attached, the tension at the center was strong and the ends became loose, and when the belt was rotated, wrinkles began to be formed, and the operation was interrupted.

The belts of Comparative Examples 1 and 2 did not cause any problem for 50,000 or more belts when rotating smoothly. Even with less than one sheet, the belt was broken and could not be used.

In the belts of Examples 1 and 2, even if cracks occurred, the cracks stopped at the fiber portion, no further axial cracks proceeded, and the belt was copied even after repeating 50,000 sheets. No abnormalities occurred in quality.

[0074]

According to the present invention, the endless belt has a uniform thickness as a whole and has a fiber direction on both sides in the width direction which is a circumferential direction orthogonal to the belt width direction, and is bent or twisted. Without having to do so, it has reinforcing fibers that are arranged straight and neatly at intervals, so it is strong against external forces such as tearing and is hard to break, even if tears etc. occur on the side of the belt, The reinforcing fibers extending in the circumferential direction can prevent the tears from expanding in the belt width direction, and have mechanical strength such that twisting and wrinkling do not occur even if meandering or belt deviation occurs. The effect described above can be obtained. Further, it is possible to form a highly elastic material layer with good precision on the belt surface thereby, the image forming apparatus having the endless belt of the present invention,
High image quality can be achieved.

[Brief description of the drawings]

FIG. 1 is a schematic view of a transfer belt according to an embodiment of the present invention.

FIG. 2 is a view illustrating a step of forming a highly elastic material layer on a belt base, which is an embodiment of a manufacturing process of the transfer belt illustrated in FIG. 1; It is a schematic perspective view which shows a mode that a high elastic material is apply | coated.

3 is an axial cross-sectional view showing a state in which the step shown in FIG. 2 has been completed and a highly elastic material layer has been formed on the surface of the belt base.

4 is a schematic perspective view showing one form of a manufacturing process of the transfer belt shown in FIG. 1 and showing a winding step of winding a reinforcing fiber around a small diameter portion of a ring as a cylindrical member.

5A and 5B are diagrams illustrating one embodiment of a process of manufacturing the transfer belt illustrated in FIG. 1, wherein FIG. 5A is an axial cross-sectional view illustrating an insertion process of inserting a ring into a belt mold, and FIG. And the reinforcing fibers are flipped off from the outer peripheral surface of the ring,
Axial sectional view showing a sticking step of sticking to the inner surface of the belt forming die, (c) is an axial sectional view showing a state in which the sticking step is completed, and the reinforcing fibers are stuck to the inner surface of the belt forming die. FIG. 9 is an axial cross-sectional view showing a state in which a coating process of applying a belt material is performed while rotating a belt forming die, and FIG. 10E is an axial cross-sectional view showing a step of removing a ring after a belt base is formed. is there.

FIG. 6 is a cross-sectional view in a direction perpendicular to the axial direction showing a state in which the reinforcing fiber wound around the outer peripheral surface of the small diameter portion of the ring is repelled from the outer peripheral surface of the small diameter portion of the ring by rotational centrifugal force and sticks to the inner surface of the belt forming die. Fig. 5
FIG. 5B is a cross-sectional view of the small diameter portion of the ring in FIG.
3C shows a cross section of the small diameter portion of the ring in FIG.

FIG. 7 is a schematic perspective view of a digital copier as an image forming apparatus provided with the endless belt according to the present invention.

8 is a schematic configuration diagram showing an internal structure of the digital copier shown in FIG.

FIG. 9 is a schematic view of a conventional endless belt to which a non-stop tape is attached.

10 is an axial sectional view showing a state where a support is inserted into the conventional endless belt shown in FIG. 9 and a high elastic material layer is formed on the surface of the endless belt.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Transfer belt (endless belt) 2,102 ... High elastic material layer 3,103 ... Reinforcing fiber 4,104 ... Support 5,105 ... Belt base 11 ... Ring (cylindrical member) 11a ... Large diameter part 11b ... Small diameter part 11c ... Cavity part 12 ... Molding die (coating die) 12a ... Inner surface 14 ... Nozzle 109 ... Digital copier 110 ... Reading part 111 ... Writing part 112 ... Recording paper 113 ... Laser part 114 ... Photoconductor drum 115 ... Toner Section 116: belt (endless belt) 117: fixing roller 118: fixing belt (endless belt) 119: transfer roller

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) B29K 105: 08 B29L 29:00 B29L 29:00 B29C 67/14 F F-term (Reference) 2H032 BA09 BA18 BA23 2H033 BA11 BA12 4F205 AA40 AC05 AD16 AG16 AJ02 AJ03 AJ11 HA07 HA24 HA34 HA37 HA46 HB01 HC02 HC12 HF01 HF05 HF24 HK02 HK04 HK05 HL02 HL12 HM04 HM08 4F213 AA40 AC05 AD16 AG16 AJ02 AJ03 WF03 WF01 WF01 WF03 WF01 WF03

Claims (11)

[Claims] Claims: 1. On both sides in the width direction, there are reinforcing fibers extending in a circumferential direction in which the fiber direction is orthogonal to the width direction, and one side of the width direction both sides including the part having the reinforcing fibers. Endless belt with a uniform thickness up to. 2. On both sides in the width direction, there are reinforcing fibers extending in the circumferential direction in which the fiber direction is orthogonal to the width direction, and one side of the width direction both sides including the part having the reinforcing fibers. A method for producing an endless belt having a uniform thickness over a period of time, wherein the reinforcing fibers are immersed in a belt raw material liquid on an inner surface of a hollow cylindrical mold, and are perpendicular to a cylindrical central axis of the mold. A method for producing an endless belt, comprising applying a belt raw material liquid to the molding die after applying along a circumferential direction, and rotating the molding die around the cylindrical central axis to form a belt. Method. 3. On both sides in the width direction, there are reinforcing fibers extending in the circumferential direction in which the fiber direction is orthogonal to the width direction, and one of the two sides in the width direction including the part having the reinforcing fibers. A method for producing an endless belt having a uniform thickness up to the inner surface of a hollow cylindrical molding die, wherein the reinforcing fibers are immersed in a solvent, and then a circumference perpendicular to the cylindrical central axis of the molding die is formed. A method for producing an endless belt, comprising applying a belt raw material liquid to the mold after applying the belt in the direction, and rotating the mold around the cylindrical central axis to form an endless belt. . 4. On both sides in the width direction, there are reinforcing fibers extending in the circumferential direction in which the fiber direction is orthogonal to the width direction, and one side of the two sides in the width direction including the part having the reinforcing fibers. A method for producing an endless belt having a uniform thickness throughout the entire length of the endless belt, wherein the reinforcing fiber immersed in a belt raw material liquid or a solvent is wound around the outer peripheral surface of the cylindrical member along the circumferential direction, The reinforcing member wound around the cylindrical member by inserting the cylindrical member from an end thereof into a molding die for forming a belt and rotating the inserted cylindrical member to utilize centrifugal force. A method for producing an endless belt, wherein fibers for use are repelled from a cylindrical member and attached to an inner surface of the mold. 5. The method for producing an endless belt according to claim 4, wherein the reinforcing fibers are attached to the inner surface of the molding die by integrally rotating the cylindrical member and the molding die. . 6. The endless belt according to claim 4, wherein the reinforcing fibers are attached to the inner surface of the mold by rotating the columnar member relative to the mold. Method. 7. The endless belt according to claim 4, wherein the cylindrical member has a large-diameter portion and a small-diameter portion, and the reinforcing fiber is wound around the small-diameter portion. Production method. 8. On both sides in the width direction, there are reinforcing fibers extending in the circumferential direction in which the fiber direction is orthogonal to the width direction, and one of the two sides in the width direction including the part having the reinforcing fibers. A method of manufacturing an endless belt having a uniform thickness throughout the entire length of the cylindrical member, a winding step of winding the reinforcing fibers immersed in a belt raw material liquid or a solvent along the circumferential direction on the outer peripheral surface of the cylindrical member. An insertion step of inserting the reinforcing fiber adhering member into a side portion of a molding die for molding the endless belt; and rotating the inserted cylindrical member to utilize centrifugal force, thereby forming the column. A bonding step in which the reinforcing fibers wound around a shaped member are flipped off from the cylindrical shaped member and stuck to the inner surface of the mold, and an application step of applying a belt raw material liquid to the inner surface of the mold, A rotating step of rotating the molding die so that the belt raw material liquid applied to the inner surface of the molding die is uniformly diffused; and a curing step of adding the belt raw material liquid uniformly diffused to the inner surface of the molding die. And a process for producing an endless belt. 9. A hollow cylindrical molding die for molding a belt, and the reinforcing fiber is wound around an outer peripheral surface and is inserted from an end of the molding die in order to attach the reinforcing fiber to an inner surface of the molding die. A molding apparatus, comprising: a cylindrical member that is rotated by rotation; a rotation driving unit that rotates the cylindrical member; and an application unit that applies a belt material liquid to the inner surface of the molding die. 10. The molding apparatus according to claim 9, wherein said cylindrical member has a large diameter portion and a small diameter portion. 11. On both sides in the width direction, there are reinforcing fibers extending in the circumferential direction in which the fiber direction is orthogonal to the width direction, and one of the two sides in the width direction including the part having the reinforcing fibers. An image forming apparatus provided with an endless belt having a uniform thickness throughout.