Endless belt and image forming apparatus

Abstract

To provide an endless belt that can prevent damage to a belt member that is provided with projection members with ends for regulating belt skew.SOLUTION: An endless belt to which a toner image formed on an image carrier is transferred, has: an endless belt member 1a; reinforcement members 3 that are provided at the ends in the width direction of the belt member along an outer peripheral surface of the belt member; and projection members 2 with ends that are provided at the ends in the width direction of the belt member along an inner peripheral surface of the belt member. An opening is formed between both ends of the projection member with ends, and the reinforcement member is formed with an overlapping part where a one end area and the other end area of the reinforcement member overlap in the circumferential direction of the belt member. When the length of the opening in the circumferential direction is defined as L1, and the length of the overlapping part as L2, the relationship of L2>L1 is established. The position of the opening in the circumferential direction is located in the area of the overlapping part.SELECTED DRAWING: Figure 5

Description

[Technical Field]

[0001] The present invention relates to an endless belt used in copying machines, printers, etc. that use an electrophotographic system or an electrostatic recording system, and to an image forming apparatus that uses the same. [Background technology]

[0002] Conventionally, image forming apparatuses have been widely used in which a toner image formed on an image carrier is transferred to an intermediate transfer belt that passes through a primary transfer section, then conveyed to a secondary transfer section, and the toner image is then secondary-transferred all at once to a sheet fed to the secondary transfer section. This intermediate transfer belt is usually formed endlessly and is supported under tension by being stretched over one or more tension rollers (drive roller, tension roller, support roller, etc.).

[0003] When an intermediate transfer belt is transported (driven in a circular motion) while being stretched across multiple tension rollers, a phenomenon known as "belt deviation" may occur, in which the intermediate transfer belt moves in the width direction (a direction substantially perpendicular to the transport direction). Belt deviation can cause problems, such as the widthwise edge of the intermediate transfer belt coming into contact with other components. To address this issue, a rib regulation system is known that provides ribs, which are protruding members, on the inner circumferential surface of the widthwise edge of the intermediate transfer belt, and provides regulation members, which can come into contact with the ribs, on the rotational axis-direction edges of the tension rollers to regulate belt deviation.

[0004] When the rib is provided on the intermediate transfer belt, the rib is adhered from one end along the inner circumferential surface of the intermediate transfer belt. However, due to variations in the components of the intermediate transfer belt and the rib and variations in adhesion, it is difficult to provide the rib continuously along the entire length of the intermediate transfer belt. This results in the formation of openings where the rib is not continuously provided along the length of the rib.

[0005] When the rib ends have openings as described above, if the belt area corresponding to the openings wraps around the outer surface of the tension roller while the intermediate transfer belt is rotating, a large load acts on the intermediate transfer belt due to bending, which may result in damage to the belt due to the load acting on the belt each time it wraps around the tension roller.

[0006] Therefore, an image forming device has been proposed in which the end of the end rib is made thinner and tapered than the other parts, thereby increasing the flexibility of the intermediate transfer belt corresponding to the opening of the rib, thereby alleviating the load acting on the belt and preventing damage to the intermediate transfer belt (Patent Document 1). [Prior art documents] [Patent documents]

[0007] [Patent Document 1] Patent Publication No. 2002-278361 Summary of the Invention [Problem to be solved by the invention]

[0008] However, as mentioned above, when the rib end portion is thinned, the opening of the rib becomes longer in part, and the area where the rib abuts against the belt deviation prevention member becomes smaller. As a result, the belt deviation increases when the opening of the rib passes through the belt deviation prevention member, causing the belt to bend and locally increasing the stress on the belt.

[0009] Furthermore, when the rib ends are not tapered, the belt shift is smaller than when the rib ends are tapered, but the stress on the belt increases locally when the rib openings pass through the belt shift control section. If the belt is repeatedly subjected to high local stress during belt conveyance, the belt may be damaged by fatigue.

[0010] The present invention has been made in view of the problems existing in such conventional technologies, and its object is to provide an endless belt capable of suppressing damage to a belt member provided with an end-shaped protruding member for regulating the belt's approaching, and an image forming apparatus using the same.

Means for Solving the Problems

[0011] A typical configuration according to the present invention for achieving the above object is an endless belt that transfers a toner image formed on an image carrier, and includes an endless belt member, an end-shaped reinforcing member provided along the outer peripheral surface at a widthwise end of the belt member, and an end-shaped protruding member provided along the inner peripheral surface at a widthwise end of the belt member. The protruding member has an opening formed between both end-shaped ends, and the reinforcing member has an overlapping portion where one end region and the other end region overlap in the circumferential direction of the belt member. When the distance of the opening in the circumferential direction is L1 and the distance of the overlapping portion is L2, they are in the relationship of L1 < L2, and in the circumferential direction, The one end region and the other end region of the reinforcing member both overlap the entire area of the opening. the position of the opening but is located within the region of the overlapping portion.

Effects of the Invention

[0012] According to the present invention, by arranging the opening of the rib between the overlapping portions of the reinforcing tape, the stress applied to the belt can be reduced.

Brief Description of the Drawings

[0013] [Figure 1] Cross-sectional view of an image forming apparatus [Figure 2] Enlarged perspective view of an end of a tension roller [Figure 3] Schematic diagram showing a cross-section of an intermediate transfer belt [Figure 4] Cross-sectional view showing belt approaching regulation [Figure 5] Perspective view of an intermediate transfer belt [Figure 6] Graph showing the stress applied to the belt by the layer of the reinforcing tape [Figure 7] A perspective view of an intermediate belt of a reference example. DETAILED DESCRIPTION OF THE INVENTION

[0014] Next, an endless belt according to a preferred embodiment of the present invention and an image forming apparatus using the same will be described with reference to the drawings.

[0015] [First embodiment] <Image forming device> Fig. 1 is an explanatory diagram of the configuration of an image forming apparatus according to this embodiment. As shown in Fig. 1, image forming apparatus 100 has image forming units 101Y, 101M, 101C, and 101K for yellow (Y), magenta (M), cyan (C), and black (K) arranged along an intermediate transfer belt 1. In other words, the image forming apparatus according to this embodiment is a full-color printer of a so-called tandem intermediate transfer type.

[0016] The image forming units 101Y, 101M, 101C, and 101K have different toner colors but are substantially the same in configuration. For example, in the yellow image forming unit 101Y, the peripheral surface of the rotating photosensitive drum 102 is charged by a charging roller 103, and an electrostatic latent image is formed by image exposure by an exposure device 104. This electrostatic latent image is developed with toner by a developing device 105 to form a yellow toner image, and the toner image is primarily transferred to the rotating intermediate transfer belt 1 by applying a bias to a primary transfer roller 106.

[0017] Similarly, a magenta toner image is transferred onto the intermediate transfer belt 1 in the image forming unit 101M, a cyan toner image is transferred onto the intermediate transfer belt 1 in the image forming unit 101C, and a black toner image is transferred onto the intermediate transfer belt 1 in the image forming unit 101K, so that a color image is formed.

[0018] In synchronization with the formation of the toner image, sheet S is transported from sheet cassette 107 to the secondary transfer section by transport rollers 108. Then, the toner image transferred onto intermediate transfer belt 1 is secondarily transferred onto sheet S by applying a bias to secondary transfer roller 109 in the secondary transfer section, and sheet S is heated and pressurized as it passes through fixing section 110, and is discharged to discharge section 111 in the state in which the toner image is fixed.

[0019] <Intermediate transfer unit> As shown in FIG. 1, the intermediate transfer belt 1 is stretched over a drive roller 201, a tension roller 202, support rollers 203 and 204, and a primary transfer roller 106, which are configured as an intermediate transfer unit 200 that is detachable from the image forming apparatus main body.

[0020] The drive roller 201 forms a secondary transfer portion by sandwiching the intermediate transfer belt 1 between it and the secondary transfer roller 109. The drive roller 201 also functions as an inner secondary transfer roller, which is an opposing roller that faces the secondary transfer roller 109 with the intermediate transfer belt 1 interposed therebetween.

[0021] The support roller 204 has a crown shape in which the outer diameter is greatest at approximately the center in the axial direction and gradually decreases toward both ends. This is to prevent the support roller 114 from bending at the center due to the tension of the intermediate transfer belt 1, causing wrinkles in the center of the intermediate transfer belt 1.

[0022] As shown in FIG. 2, the tension roller 202 is rotatably supported by bearing members 205 at both ends in the direction of its rotation axis. The bearing members 205 are attached to a frame 206 so as to be movable (slidable). Both bearing members 205 are biased by the compressive force of tension springs 207, which are compression springs serving as biasing means. The bearing members 205 are moved (slid) from the inner circumferential surface of the intermediate transfer belt 1 toward the outer circumferential surface thereof along the biasing direction of the tension springs 207. As a result, the tension roller 202 biases the intermediate transfer belt 1 from the inner circumferential surface toward the outer circumferential surface thereof, thereby applying tension to the intermediate transfer belt 1. In addition, a regulating collar 208 is provided at each end in the direction of the rotation axis of the tension roller 202 to regulate the deviation of the intermediate transfer belt 1.

[0023] <Endless belt> Next, the intermediate transfer belt will be described. The intermediate transfer belt 1 is an endless belt that is stretched around the drive roller 201, tension roller 202, etc. as described above and rotates in response to the image forming operation. The intermediate transfer belt 1 of this embodiment is provided with reinforcing members on the outer peripheral surfaces of both ends in the width direction of the belt member (a direction substantially perpendicular to the belt conveyance direction), and with protruding members with ends along the inner peripheral surfaces of both ends.

[0024] Here, the protruding member and the reinforcing member will be specifically described. Fig. 3 is a schematic perspective view showing a cross section of the end of the intermediate transfer belt 1 on the rear side as viewed from the front of the image forming apparatus main body. Note that Fig. 3 shows only the end of the intermediate transfer belt 1 on the rear side of the main body, but in this embodiment, the end on the front side of the main body has the same configuration (symmetrical with respect to the center in the width direction of the intermediate transfer belt 1).

[0025] As shown in Fig. 3, the intermediate transfer belt 1 of this embodiment has ribs 2, which are protruding members, on both widthwise ends of the inner peripheral surface 1b of the endless belt member 1a. The ribs 2 of this embodiment have a rectangular cross section protruding from the inner peripheral surface 1b and are adhered along the inner peripheral surface 1b. As shown in the cross-sectional view of the vicinity of the end of the tension roller in Fig. 4, when the intermediate transfer belt 1 rotates, the ribs 2 come into contact with the end 208a of a regulating collar 208 provided at the end of the tension roller 202 in the rotational axis direction, thereby regulating belt deviation.

[0026] Further, a reinforcing tape 3 serving as a reinforcing member is provided on the outer peripheral surface 1c at both ends in the width direction of the intermediate transfer belt 1. In this embodiment, the reinforcing tape 3 is adhered along the outer peripheral surface 1c of the intermediate transfer belt 1.

[0027] 4, the rib 2 and the reinforcing tape 3 in this embodiment are respectively positioned slightly inward from the edges of both ends in the width direction of the intermediate transfer belt 1. The rib 2 and the reinforcing tape 3 are positioned so as to at least partially overlap each other in the width direction of the intermediate transfer belt 1, and in this embodiment, the area of the rib 2 is positioned within the area of the reinforcing tape 3 in the width direction.

[0028] The belt member 1a of this embodiment is a resin belt with a polyimide (PI) base layer, a tensile modulus of elasticity E of 18,000 N / cm2, and a thickness of 0.08 mm. The thickness of the belt member 1a is preferably in the range of 0.02 mm to 0.50 mm. If the belt member 1a is too thin, it will not have sufficient durability against wear, and if it is too thick, it will be difficult to bend between the drive roller 201, tension roller 202, and support rollers 203 and 204, resulting in deformation or breakage.

[0029] In this embodiment, the rib 2 is made of a material mainly composed of urethane rubber. The reinforcing tape 3 is made of the same material as the belt member 1a. The materials of the intermediate transfer belt 1, the rib 2, and the reinforcing tape 3 are not particularly limited.

[0030] <Relationship between rib and reinforcing tape> Next, a description will be given of the relationship between the rib 2 and the reinforcing tape 3. Fig. 5 is a perspective view of the intermediate transfer belt 1 showing the relationship between the rib 2 and the reinforcing tape 3.

[0031] As described above, the ribs 2 are bonded to the ends of the inner peripheral surface 1b of the intermediate transfer belt 1. Because the ribs 2 are end-shaped members, they are bonded from one end and then along the inner peripheral surface 1b of the belt member 1a. However, due to variations in the components of the belt member 1a and the ribs 2 and variations in bonding, it is difficult to provide the ribs 2 continuously along the entire length of the belt member 1a. As a result, openings W are formed along the length of the ribs 2 where the ribs 2 are not continuously provided. Here, the openings W also include a state in which the ends of the ribs 2 are in contact with each other with no gaps between them.

[0032] Furthermore, the reinforcing tape 3 adhered to the end of the outer peripheral surface 1c of the belt member 1a is adhered by providing an overlapping portion X where the tape ends overlap, thereby ensuring reliable adhesion of the tape ends.

[0033] 6 is a graph showing the stress applied to the belt member 1a depending on the thickness of the reinforcing tape 3 of this embodiment. As can be seen from this graph, the thickness of the reinforcing tape 3 in the overlapping portion is twice as thick as that in the non-overlapping portion, increasing the rigidity. Therefore, by providing the overlapping portion X, it is possible to suppress deformation of the belt member 1a in that portion.

[0034] In this embodiment, the opening W in the circumferential direction of the intermediate transfer belt 1 is arranged so as to be located within the region of the overlapping portion X. Further, the length L1 of the opening W of the rib 2 in the circumferential direction of the intermediate transfer belt 1 and the length L2 of the overlapping portion X of the reinforcing tape 3 are configured to have a relationship of L1 < L2. That is, the length L1 of the region where the ribs from one end to the other end of the end-shaped rib 2 are not adhered in the circumferential direction of the intermediate transfer belt 1 is set shorter than the length L2 of the region where two reinforcing tapes 3 are overlapped and adhered, and the opening W is arranged so as to be within the region of the overlapping portion X.

[0035] As described above, the portion where the reinforcing tapes 3 are overlapped has higher rigidity than the non-overlapped portion. Therefore, when the opening W of the rib 2 is located in this region, local deformation of the intermediate transfer belt 1 is suppressed when the opening W passes through the regulating collar 208, and the stress applied to the intermediate transfer belt 1 is reduced.

[0036] Here, if the length of the overlapping portion X of the reinforcing tape 3 is set longer than the length of the opening W of the rib 2, local deformation of the intermediate transfer belt 1 can be suppressed. Therefore, it is not necessary to set the length of the overlapping portion X of the reinforcing tape 3 long. Therefore, it is desirable that the length of the overlapping portion X of the reinforcing tape 3 is set to be 1 / 4 or less of the circumferential length of the intermediate transfer belt 1.

[0037] As described above, by arranging the opening W of the rib 2 between the overlapping portions X of the reinforcing tapes 3, the stress applied to the intermediate transfer belt 1 can be reduced. That is, it becomes possible to provide an image forming apparatus that can suppress breakage of the intermediate transfer belt 1.

[0038] 〔 Reference example 〕 Next Reference example the intermediate transfer belt according to will be described. FIG. 7 is Reference example a perspective view of the intermediate transfer belt according to.

[0039] 7, a rib 2 having an end is adhered to both widthwise ends of the inner peripheral surface 1b of the belt member 1a, and an opening W is formed between the both ends. In addition, end tapes 4 serving as belt reinforcing means are adhered to both widthwise ends of the outer peripheral surface 1c of the intermediate transfer belt 1 at positions facing the opening W of the rib 2.

[0040] Book Reference example The reinforcing tape 3 is adhered to the entire circumferential circumference of the belt member 1a, but no overlapping portion is formed by the reinforcing tape 3 as in the previously described embodiment. On the other hand, on the outer peripheral surface corresponding to the region where the opening W is provided in the circumferential direction, the end tape 4 is adhered to the belt member 1a and the reinforcing tape 3 so as to overlap the reinforcing tape 3, thereby forming the overlapping portion X. Therefore, in the region of the opening W, the reinforcing tape 3 and the end tape 4 overlap, increasing the thickness and rigidity of that portion, thereby suppressing deformation of the intermediate transfer belt 1 at the rib opening W. This suppresses deformation of the intermediate transfer belt 1 when the opening W of the rib 2 passes through the regulating collar 208, thereby reducing the stress applied to the intermediate transfer belt 1.

[0041] Book Reference example In this case, As mentioned above Compared to the previous embodiment, the ease of assembly is improved because there is no need to worry about the position where the long reinforcing tape starts to be attached. [Explanation of symbols]

[0042] S...Seat W...Opening X: overlapping part 1...Intermediate transfer belt 1a ... Belt member 1b…Inner peripheral surface 1c...Outer surface 2. Ribs 3...Reinforcing tape 4...Edge tape 100...Image forming device 101Y,101M,101C,101K...Image forming section 102...Photosensitive drum 103...Charging roller 104... exposure equipment 105...Developing device 106...Primary transfer roller 107 ... Sheet cassette 108...Transport roller 109...Secondary transfer roller 110...fixing part 111...Discharge section 200...Intermediate transfer unit 201...Drive roller 202...tension roller 203, 204 ... Support rollers 205...Bearing member 206...frame 207...tension spring 208...Regulation color

Claims

1. In an endless belt that transfers a toner image formed on an image carrier, an endless belt member; a reinforcing member having an end and provided along an outer peripheral surface at an end in the width direction of the belt member; a protruding member having an end and provided along an inner peripheral surface of the belt member at an end in the width direction; and The protruding member has an opening formed between both ends thereof, the reinforcing member has an overlapping portion where one end region and the other end region overlap in the circumferential direction of the belt member; When the distance between the openings in the circumferential direction is L1 and the distance between the overlapping portions is L2, a relationship of L1<L2 is satisfied, One end region and the other end region of the reinforcing member in the circumferential direction both overlap the entire area of the opening, so that the position of the opening is located within the area of the overlapping portion. An endless belt characterized by:

2. An image forming apparatus that forms an image by primarily transferring a toner image formed on an image carrier onto an endless belt, and then secondarily transferring the toner image transferred onto the endless belt onto a sheet, The endless belt is an endless belt member; a reinforcing member having an end and provided along an outer peripheral surface at an end in the width direction of the belt member; a protruding member having an end and provided along an inner peripheral surface of the belt member at an end in the width direction; and The protruding member has an opening formed between both ends thereof, the reinforcing member has an overlapping portion where one end region and the other end region overlap in the circumferential direction of the belt member; When the distance between the openings in the circumferential direction is L1 and the distance between the overlapping portions is L2, a relationship of L1<L2 is satisfied, One end region and the other end region of the reinforcing member in the circumferential direction both overlap the entire area of the opening, so that the position of the opening is located within the area of the overlapping portion. An image forming apparatus characterized by:

Images