Patent Grant
10955772
Embodiments described herein relate generally to a belt positioning structure, a belt and roller unit, and an image forming apparatus.
As an image forming apparatus, there are a multi-function peripheral (MFP) which is a multifunction machine, a printer, a copying machine, and the like. The image forming apparatus transfers a toner image to an endless transfer belt and transfers the toner image to a recording medium such as a paper sheet.
The transfer belt may include a rib on an inner peripheral surface thereof for preventing the belt from being deviated. A roller around which the transfer belt is wound may include a regulating plate on which the rib can abut. The regulating plate forms an inclined surface on which the rib can abut. The regulating plate returns the rib and the transfer belt to a normal position by the inclined surface. For that reason, skewing of the transfer belt can be suppressed.
When the transfer belt is skewed greatly, a deviating force of the belt may exceed a regulation force for returning the rib to the normal position by the inclined surface of the regulating plate. In this case, the rib rides up on the inclined surface of the regulating plate. When the rib rides over the inclined surface up to a cylindrical belt winding surface, the rib and the transfer belt may come off from their normal positions and fall off.
In general, according to one embodiment, there is provided a belt positioning structure including a belt roller, a belt, a projection, and a first rotating body. The belt roller is rotatable about a roller axis. The belt is wound around the belt roller. The projection is provided so as to protrude from an inner peripheral surface of the belt. The first rotating body regulates the projection from moving in a first direction approaching the belt roller along the roller axis. The first rotating body is rotatable around an axis. At least a portion of an outer peripheral surface of the first rotating body faces a side surface of the projection on the first direction side.
Hereinafter, a belt positioning structure, a belt and roller unit, and an image forming apparatus according to an embodiment will be described with reference to the accompanying drawings. In the respective drawings, the same components are denoted by the same reference numerals. In each drawing, the size and shape of each member may be exaggerated or simplified for easy viewing.
As illustrated in
A configuration of the image forming apparatus 1 is not particularly limited. For example, the image forming apparatus 1 includes a main body 11. On the upper part of the main body 11, a document table 12 including transparent glass is provided. An automatic document feeder (ADF) 13 is provided on the document table 12. On the upper part of the main body 11, an operation unit 14 is provided. The operation unit 14 includes an operation panel 14a including various keys and a touch panel type operation and display unit 14b.
A scanner unit 15 is provided below the ADF 13. The scanner unit 15 reads a document sent by the ADF 13 or a document placed on the document table 12. The scanner unit 15 generates image data of the document. For example, the scanner unit 15 includes an image sensor 16. For example, the image sensor 16 may be a contact type image sensor. The image sensor 16 moves along the document table 12 when reading an image of the document placed on the document table 12.
A sheet feed cassette 18A (18B) includes a sheet feed mechanism 19A (19B). The expression “The sheet feed cassette 18A (18B) includes the sheet feed mechanism 19A (19B)” means that both the sheet feed cassette 18A includes the sheet feed mechanism 19A, and the sheet feed cassette 18B includes the sheet feed mechanism 19B. The same applies to the following description.
The sheet feed mechanism 19A (19B) picks up sheets (sheet-shaped recording media such as paper sheets) P one by one from the sheet feed cassette 18A (18B) and sends the sheets to a conveyance path of the sheet P. For example, the sheet feed mechanism 19A (19B) may include a pickup roller, a separation roller, and a sheet feed roller.
A manual sheet feed unit 18C includes a manual sheet feed mechanism 19C. The manual sheet feed mechanism 19C picks up the sheets P one by one from the manual sheet feed unit 18C and sends the sheets P to the conveyance path.
A printer unit (image forming unit) 17 forms an image on the sheet P based on image data read by the scanner unit 15 or image data generated by a personal computer or the like. The printer unit 17 is, for example, a tandem-type color printer.
The printer unit 17 includes image forming parts 22Y, 22M, 22C, and 22K for colors of yellow (Y), magenta (M), cyan (C), and black (K) corresponding to color separation components of a color image, an exposure device 23, and an intermediate transfer belt 24.
A configuration of the printer unit 17 is not limited to this, and the printer unit 17 may include two or three image forming parts, or the printer unit 17 may include five or more image forming parts.
Although not illustrated, the exposure device 23 includes a light source, a polygon mirror, an f-0 lens, a reflection mirror, and the like. The exposure device 23 irradiates a surface of a photoreceptor drum of each of the image forming parts 22Y, 22M, 22C, and 22K with exposure light, based on the image data.
The configurations of the image forming parts 22Y, 22M, 22C, and 22K are the same as each other except that a color of a toner is different. As the toner, any of a normal color toner and a decolorable toner may be used. Here, the decolorable toner is a toner that becomes transparent when heated at a predetermined temperature or higher. The image forming apparatus 1 may be the image forming apparatus 1 that can use the decolorable toner, or may be the image forming apparatus 1 that cannot use the decolorable toner.
The intermediate transfer belt 24 is an endless belt. The intermediate transfer belt 24 is wound around a secondary transfer backup roller 32, a cleaning backup roller 33, and a tension roller. In the embodiment, when the secondary transfer backup roller 32 is driven to rotate, the intermediate transfer belt 24 runs around (rotates). An arrow R in the figure indicates a driving direction (rotation direction) of the secondary transfer backup roller 32.
Around the intermediate transfer belt 24, the image forming parts 22Y, 22M, 22C, and 22K, a secondary transfer roller 37, and a belt cleaning mechanism 38 are disposed. A plurality of primary transfer rollers 36 are disposed on the inner peripheral side of the intermediate transfer belt 24 so as to face the image forming parts 22Y, 22M, 22C, and 22K.
The printer unit 17 of the embodiment includes a belt and roller unit 31 that is detachable (replaceable) from the main body of the printer unit 17. The belt and roller unit 31 is configured to include the intermediate transfer belt 24, the secondary transfer backup roller 32, the cleaning backup roller 33, the tension roller 34, and the plurality of primary transfer rollers 36.
Hereinafter, a configuration common to the image forming parts 22Y, 22M, 22C, and 22K will be described using the image forming part 22K as an example.
The image forming part 22K includes a photoreceptor 26K, a charger 27K, a developing device 28K, and a cleaner 29K.
The photoreceptor 26K is formed in a drum shape. An electrostatic latent image such as a character or an image is formed on the surface of the photoreceptor 26K by exposure light LK. The charger 27K charges the surface of the photoreceptor 26K. The developing device 28K supplies a toner to the surface of the photoreceptor 26K to develop the electrostatic latent image. The cleaner 29K cleans the surface of the photoreceptor 26K.
The primary transfer roller 36 of the image forming part 22K forms a primary transfer nip by sandwiching the intermediate transfer belt 24 between the primary transfer roller 36 and the photoreceptor 26K. A power source (not illustrated) is connected to the primary transfer roller 36. At least one of a predetermined direct current (DC) voltage and a predetermined alternating current (AC) voltage is applied to the primary transfer roller 36.
The secondary transfer roller 37 forms a secondary transfer nip by sandwiching the intermediate transfer belt 24 between the secondary transfer roller 37 and the secondary transfer backup roller 32. A power source (not illustrated) is connected to the secondary transfer roller 37, similarly to the primary transfer roller 36. At least one of a predetermined DC voltage and a predetermined AC voltage is applied to the secondary transfer roller 37.
The transfer in the image forming apparatus 1 includes a first transfer step and a second transfer step. In the first transfer step, the toner images formed on the photoreceptors 26K of the image forming parts 22Y, 22M, 22C, and 22K are transferred to the intermediate transfer belt 24. In the second transfer step, the toner images transferred to the intermediate transfer belt 24 are transferred (printed) to the sheet P which is a recording medium.
The belt cleaning mechanism 38 includes a cleaning brush and a cleaning blade (reference numerals thereof are omitted) disposed so as to abut on the intermediate transfer belt 24. A waste toner transport hose (not illustrated) extends from the belt cleaning mechanism 38 and is connected to a waste toner container (not illustrated).
A supply unit 41 is disposed above the image forming parts 22Y, 22M, 22C, and 22K. The supply unit 41 supplies the toner to each of the image forming parts 22Y, 22M, 22C, and 22K. The supply unit 41 includes toner cartridges 42Y, 42M, 42C, and 42K. The toner cartridges 42Y, 42M, 42C, and 42K contain yellow, magenta, cyan, and black toners, respectively.
Each of the toner cartridges 42Y, 42M, 42C, and 42K is provided with a marking portion (not illustrated) that allows a main control unit 53, which will be described later, to detect a type of toner contained in each of the toner cartridges. The marking portion includes at least information on colors of the toners of the toner cartridges 42Y, 42M, 42C, and 42K and information for identifying whether the toner is the normal toner or the decolorable toner.
A replenishment path (not illustrated) is provided between each of the toner cartridges 42Y, 42M, 42C, and 42K and the corresponding developing device. The toner is supplied from each of the toner cartridges 42Y, 42M, 42C, and 42K to the corresponding developing device via the replenishment path.
Sheet feed rollers 45A and registration rollers 46 are provided on a conveyance path from the sheet feed cassette 18A to the secondary transfer roller 37. The sheet feed rollers 45A convey the sheet P picked up from the sheet feed cassette 18A by the sheet feed mechanism 19A. The registration rollers 46 adjust a position of a leading end of the sheet P fed from the sheet feed rollers 45A at an abutment position on each other.
The registration rollers 46 convey the sheet P to the secondary transfer nip.
Sheet feed rollers 45B are provided on a conveyance path from the sheet feed cassette 18B to the sheet feed rollers 45A. The sheet feed rollers 45B convey the sheet P picked up from the sheet feed cassette 18B by the sheet feed mechanism 19B toward the sheet feed rollers 45A.
A conveyance path is formed by a conveyance guide 48 between a manual sheet feed mechanism 19C and the registration rollers 46. The manual sheet feed mechanism 19C conveys the sheet P picked up from a manual sheet feed unit 18C toward the conveyance guide 48. The sheet P moving along the conveyance guide 48 reaches the registration rollers 46.
A fixing unit (fixing device) 56 is disposed on a downstream side (upper side in the figure) of the secondary transfer roller 37 in the conveyance direction of the sheet P.
Conveyance rollers 50 are disposed on a downstream side (upper left side in the figure) of the fixing unit 56 in the conveyance direction of the sheet P. The conveyance rollers 50 discharge the sheet P to a sheet discharge unit 51.
A reverse conveyance path 52 is disposed on an upstream side (right side in the figure) of the fixing unit 56 in the conveyance direction of the sheet P. In the reverse conveyance path 52, the sheet P is reversed and guided toward the secondary transfer roller 37. The reverse conveyance path 52 is used when performing double-sided printing.
The image forming apparatus 1 includes a main control unit 53 that controls the entire image forming apparatus 1. The main control unit 53 includes a central processing unit (CPU), a memory, and the like.
The fixing unit 56 includes a fixing belt (belt), a pressurizing roller (roller), and a heater (heating unit) (all are not illustrated). The fixing belt and the pressurizing roller are disposed side by side. The pressurizing roller is pressurized toward the fixing belt side by a pressurizing unit (not illustrated). A nip in which the sheet P is pinched is formed in a portion against where the pressurizing roller and the fixing belt are pressed.
The pressurizing roller is driven to rotate by a drive source such as a motor (not illustrated). When the pressurizing roller is driven to rotate, the driving force of the pressurizing roller is transmitted to the fixing belt through the nip, and the fixing belt is driven to rotate. The sheet P pinched in the nip is conveyed downstream side in the conveyance direction by the rotation of the pressurizing roller and the fixing belt. The fixing belt is heated by the heater, and the toner image transferred to the sheet P is fixed to the sheet P by the heat and pressure of the pressurizing roller. The sheet P after image formation is discharged to the sheet discharge unit 51.
During execution of a printing operation, the intermediate transfer belt 24 may be skewed to run obliquely with respect to a normal rotation direction, or may be deviated to one side in the axis direction of the roller. Such an event may cause excessive input or deformation of the intermediate transfer belt 24, which may lead to breakage or dropout of the intermediate transfer belt 24. For that reason, the image forming apparatus 1 includes a belt positioning structure 30 for preventing the intermediate transfer belt 24 from being deviated.
A belt positioning structure 30A, which is a first example of the belt positioning structure 30, will be described with reference to
As illustrated in
As illustrated in
For example, the positioning projection 61 is made of an elastic member such as synthetic rubber separate from the intermediate transfer belt 24. The positioning projection 61 is fixed to the inner peripheral surface 24b of the intermediate transfer belt 24 by bonding or the like, and is capable of running around the intermediate transfer belt 24 integrally. The positioning projection 61 is disposed close to a side edge 24a of the intermediate transfer belt 24.
In
As illustrated in
The first rotating body 71 is rotatably supported by a shaft member 73. The shaft member 73 includes a head portion 73a and a support shaft 73b extending from the head portion 73a. The support shaft 73b is inserted into the insertion hole 71c of the first rotating body 71. With this configuration, the first rotating body 71 is rotatable around the center axis C1. The head portion 73a is accommodated in the recess 71b. For example, the first rotating body 71 is made of an elastic member such as synthetic rubber.
The first rotating body 71 and the shaft member 73 are provided on the inner peripheral surface 24b side of the intermediate transfer belt 24. The first rotating body 71 is installed such that the end face 71a faces the inner peripheral face 24b. The end face 71a of the first rotating body 71 is preferably apart from the inner peripheral face 24b. For example, the center axis C1 of the first rotating body 71 is perpendicular to the intermediate transfer belt 24.
At least a portion of an outer peripheral surface 71d of the first rotating body 71 faces an inner side surface 61a (left surface in
When the intermediate transfer belt 24 and the positioning projection 61 move in the first direction D1, the inner side surface 61a of the positioning projection 61 abuts on the outer peripheral surface 71d of the first rotating body 71. For that reason, the movement of the intermediate transfer belt 24 in the first direction D1 is regulated. With this configuration, deviation of the intermediate transfer belt 24 can be suppressed. Therefore, the reliability of the positioning of the intermediate transfer belt 24 can be improved.
When the positioning projection 61 abuts on the outer peripheral surface 71d of the first rotating body 71, the first rotating body 71 rotates around the center axis C1 as the intermediate transfer belt 24 and the positioning projection 61 run. For that reason, the frictional resistance between the positioning projection 61 and the first rotating body 71 can be suppressed.
The second rotating body 72 is formed in a columnar shape. A reference numeral C2 is the center axis (rotating body axis) of the second rotating body 72. A direction along a center axis C2 is referred to as the axial direction. At the central part of the second rotating body 72, an insertion hole 72c penetrating the second rotating body 72 in the axial direction is formed.
The second rotating body 72 is rotatably supported by a shaft member 74. The shaft member 74 includes a head portion 74a and a support shaft 74b extending from the head portion 74a. The support shaft 74b is inserted into the insertion hole 72c of the second rotating body 72. With this configuration, the second rotating body 72 can rotate around the center axis C2. The center axis C2 of the second rotating body 72 is parallel to the center axis C (roller axis) (see
The second rotating body 72 and the shaft member 74 are provided on the outer peripheral surface 24c side of the intermediate transfer belt 24. The second rotating body 72 is installed such that at least a portion of the outer peripheral surface 72d faces the outer peripheral surface 24c of the intermediate transfer belt 24. The outer peripheral surface 72d of the second rotating body 72 is preferably separated from the outer peripheral surface 24c. At a point of the outer peripheral surface 72d closest to the outer peripheral surface 24c, a direction of a tangent line perpendicular to the center axis C2 is parallel to a running direction of the intermediate transfer belt 24.
A distance a between the outer peripheral surface 72d of the second rotating body 72 and the outer peripheral surface 24c of the intermediate transfer belt 24 is preferably smaller than a thickness A of the positioning projection 61. With this configuration, it is possible to regulate that the positioning projection 61 comes off the position where the positioning projection 61 can be made to abut on the first rotating body 71.
At least a portion of the outer peripheral surface 72d of the second rotating body 72 faces an outer peripheral surface 61c (upper surface in
When the intermediate transfer belt 24 and the positioning projection 61 move in a direction (upward in
When the intermediate transfer belt 24 abuts on the outer peripheral surface 72d of the second rotating body 72, the second rotating body 72 rotates around the center axis C2 as the intermediate transfer belt 24 runs. For that reason, the frictional resistance between the intermediate transfer belt 24 and the second rotating body 72 can be suppressed.
Next, a belt positioning structure 30B which is a second example of the belt positioning structure 30 will be described with reference to
As illustrated in
An outer peripheral surface 171d of the first rotating body 171 includes a first region 171d1 and a second region 171d2. The first region 171d1 is a region of the outer peripheral surface 171d extending from one end 171a (first end 171a) in the axial direction of the first rotating body 171 to the center in the axial direction. The first region 171d1 is tapered such that the outer diameter gradually increases from the first end 171a toward the center in the axial direction. The second region 171d2 is a region of the outer peripheral surface 171d extending from the other end 171b (second end 171b) in the axial direction of the first rotating body 171 to the center in the axial direction. The second region 171d2 is tapered such that the outer diameter gradually increases from the second end 171b toward the center in the axial direction.
An insertion hole 171c penetrating in the axial direction is formed in the first rotating body 171.
The first rotating body 171 is rotatably supported by the shaft member 73. The support shaft 73b of the shaft member 73 is inserted into the insertion hole 171c of the first rotating body 171. With this configuration, the first rotating body 171 is rotatable around a center axis C3.
The first rotating body 171 and the shaft member 73 are provided on the inner peripheral surface 24b side of the intermediate transfer belt 24.
At least a portion of the first region 171d1 of the outer peripheral surface 171d of the first rotating body 171 faces the inner side surface 61a (left side surface in
At least a portion of the second region 171d2 of the outer peripheral surface 171d of the first rotating body 171 faces the inner peripheral surface 24b. The second region 171d2 is preferably separated from the inner peripheral surface 24b. The center axis C3 of the first rotating body 171 is inclined in a direction away from the intermediate transfer belt 24 as the center axis C3 goes in the second direction D2.
When the intermediate transfer belt 24 and the positioning projection 61 move in the first direction D1, the inner side surface 61a of the positioning projection 61 abuts on the first region 171d1 of the outer peripheral surface 171d of the first rotating body 171. For that reason, the movement of the intermediate transfer belt 24 in the first direction D1 is regulated. With this configuration, the deviation of the intermediate transfer belt 24 can be suppressed. Therefore, the reliability of the positioning of the intermediate transfer belt 24 can be improved.
When the positioning projection 61 abuts on the first region 171d1 of the outer peripheral surface 171d of the first rotating body 171, the first rotating body 171 rotates around the center axis C3 as the intermediate transfer belt 24 and the positioning projection 61 run. For that reason, the frictional resistance between the positioning projection 61 and the first rotating body 171 can be suppressed.
When the intermediate transfer belt 24 moves in the direction (downward in
When the intermediate transfer belt 24 abuts on the second region 171d2 of the outer peripheral surface 171d of the first rotating body 171, the first rotating body 171 rotates around the center axis C3 as the intermediate transfer belt 24 and the positioning projection 61 run. For that reason, the frictional resistance between the intermediate transfer belt 24 and the first rotating body 171 can be suppressed.
The second rotating body 172 includes a columnar main portion 172a, and a flange part 172b provided at one end (end in the second direction D2) in the axial direction of the columnar main portion 172a. A reference symbol C4 is the center axis (rotating body axis) of the second rotating body 172. At the center of the second rotating body 172, an insertion hole 172c penetrating the second rotating body 172 in the axial direction is formed.
The second rotating body 172 is rotatably supported by the shaft member 74. The support shaft 74b of the shaft member 74 is inserted into the insertion hole 172c of the second rotating body 172. With this configuration, the second rotating body 172 is rotatable around a center axis C4. The center axis C4 of the second rotating body 172 is parallel to the center axis C (roller axis) (see
The second rotating body 172 and the shaft member 74 are provided on the outer peripheral surface 24c side of the intermediate transfer belt 24. The second rotating body 172 is installed such that at least a portion of an outer peripheral surface 172d of the columnar main portion 172a faces the outer peripheral surface 24c of the intermediate transfer belt 24. The outer peripheral surface 172d of the second rotating body 172 is preferably separated from the outer peripheral surface 24c.
At least a portion of the outer peripheral surface 172d of the second rotating body 172 faces the outer peripheral surface 61c (upper surface in
The flange part 172b is formed to protrude radially outward of the second rotating body 172 with respect to the columnar main portion 172a. At least a portion of an inner side surface 172b1 of the flange part 172b on the first direction D1 side faces an end surface 24a1 of the side edge 24a of the intermediate transfer belt 24 on the second direction D2 side. The inner side surface 172b1 is preferably separated from the end surface 24a1.
A portion of the inner side surface 172b1 may face an outer side surface 61b (right side surface in
When the intermediate transfer belt 24 and the positioning projection 61 move in a direction (upward in
When the intermediate transfer belt 24 abuts on the outer peripheral surface 172d of the second rotating body 172, the second rotating body 172 rotates around the center axis C4 as the intermediate transfer belt 24 runs. For that reason, the frictional resistance between the intermediate transfer belt 24 and the second rotating body 172 can be suppressed.
The flange part 172b can regulate the intermediate transfer belt 24 from moving to the second direction D2 side.
Next, a belt positioning structure 30C which is a third example of the belt positioning structure 30 will be described with reference to
As illustrated in
An outer peripheral surface 271d of the first rotating body 271 includes a first region 271d1 and a second region 271d2. The first region 271d1 is a tapered region in which the outer diameter gradually decreases from a position close to a first end 271a toward the center in the axial direction. The second region 271d2 is a tapered region in which the outer diameter gradually decreases from a position close to a second end 271b toward the center in the axial direction.
An insertion hole 271c penetrating in the axial direction is formed in the first rotating body 271.
The first rotating body 271 is rotatably supported by the shaft member 73. The support shaft 73b of the shaft member 73 is inserted into the insertion hole 271c of the first rotating body 271. With this configuration, the first rotating body 271 is rotatable around a center axis C5.
The first rotating body 271 and the shaft member 73 are provided on the inner peripheral surface 24b side of the intermediate transfer belt 24.
At least a portion of the first region 271d1 of the outer peripheral surface 271d of the first rotating body 271 faces the inner side surface 61a (left side surface in
At least a portion of the second region 271d2 of the outer peripheral surface 271d of the first rotating body 271 faces the inner peripheral surface 61d (lower surface in
When the intermediate transfer belt 24 and the positioning projection 61 move in the first direction D1, the inner side surface 61a of the positioning projection 61 abuts on the first region 271d1 of the outer peripheral surface 271d of the first rotating body 271. For that reason, the movement of the intermediate transfer belt 24 in the first direction D1 is regulated. With this configuration, the deviation of the intermediate transfer belt 24 can be suppressed. Therefore, the reliability of the positioning of the intermediate transfer belt 24 can be improved.
When the positioning projection 61 abuts on the first region 271d1 of the outer peripheral surface 271d of the first rotating body 271, the first rotating body 271 rotates around the center axis C5 as the intermediate transfer belt 24 and the positioning projection 61 run. For that reason, the frictional resistance between the positioning projection 61 and the first rotating body 271 can be suppressed.
When the intermediate transfer belt 24 and the positioning projection 61 move in a direction approaching the center axis C (see
When the positioning projection 61 abuts on the second region 271d2 of the outer peripheral surface 271d of the first rotating body 271, the first rotating body 271 rotates around the center axis C5 as the intermediate transfer belt 24 and the positioning projection 61 run. For that reason, the frictional resistance between the positioning projection 61 and the first rotating body 271 can be suppressed.
An outer peripheral surface 272d of the second rotating body 272 includes a third region 272d1 and a fourth region 272d2. The third region 272d1 is a tapered region in which the outer diameter gradually decreases from a position close to a first end 272a toward the center in the axial direction. The fourth region 272d2 is a tapered region in which the outer diameter gradually decreases from a position close to a second end 272b toward the center in the axial direction.
An insertion hole 272c penetrating in the axial direction is formed in the second rotating body 272.
The second rotating body 272 is rotatably supported by the shaft member 74. The support shaft 74b of the shaft member 74 is inserted into the insertion hole 272c of the second rotating body 272. With this configuration, the second rotating body 272 is rotatable around a center axis C6.
At least a portion of the third region 272d1 of the outer peripheral surface 272d of the second rotating body 272 faces the end surface 24a1 of the side edge 24a of the intermediate transfer belt 24 on the second direction D2 side. The third region 272d1 is preferably separated from the end face 24a1.
A portion of the third region 272d1 may face the outer side surface 61b (right side surface in
At least a portion of the fourth region 272d2 of the outer peripheral surface 272d of the second rotating body 272 faces the outer peripheral surface 24c of the intermediate transfer belt 24. The fourth region 272d2 of the second rotating body 272 is preferably separated from the outer peripheral surface 24c.
At least a portion of the fourth region 272d2 of the second rotating body 272 faces the outer peripheral surface 61c (upper surface in
The center axis C6 of the second rotating body 272 is parallel to the center axis C5 of the first rotating body 271.
When the intermediate transfer belt 24 and the positioning projection 61 move in a direction (upward in
When the intermediate transfer belt 24 abuts on the outer peripheral surface 272d of the second rotating body 272, the second rotating body 272 rotates around the center axis C6 as the intermediate transfer belt 24 runs. For that reason, the frictional resistance between the intermediate transfer belt 24 and the second rotating body 272 can be suppressed.
The third region 272d1 can regulate the intermediate transfer belt 24 from moving to the second direction D2 side.
Next, a belt positioning structure 30d which is a fourth example of the belt positioning structure 30 will be described with reference to
As illustrated in
The first urging mechanism 81 includes a first shaft holding portion 83 and a first urging body 84. The first shaft holding portion 83 includes a substrate 83a and a pair of side plates 83b, 83b. The side plate portions 83b, 83b hold a shaft member 273 that rotatably supports the first rotating body 271. The first urging body 84 is connected to the substrate 83a. The first urging body 84 is, for example, an elastic member such as a coil spring. The first urging body 84 urges the first rotating body 271 in a direction approaching the positioning projection 61 via the first shaft holding portion 83.
The second urging mechanism 82 includes a second shaft holding portion 85 and a second urging body 86. The second shaft holding portion 85 includes a substrate 85a and a pair of side plates 85b, 85b. The side plates 85b, 85b hold a shaft member 274 that rotatably supports the second rotating body 272. The second urging body 86 is connected to the substrate 85a. The second urging body 86 is, for example, an elastic member such as a coil spring. The second urging body 86 urges the second rotating body 272 in a direction approaching the positioning projection 61 via the second shaft holding portion 85.
In the belt positioning structure 30D, the first rotating body 271 and the second rotating body 272 are urged toward the positioning projection 61 by the first urging mechanism 81 and the second urging mechanism 82, and thus the positioning projection 61 can be stably positioned. Therefore, the reliability of the positioning of the intermediate transfer belt 24 can be improved.
In the belt positioning structure 30D, although the first rotating body 271 is provided with the first urging mechanism 81 and the second rotating body 272 is provided with the second urging mechanism 82, the urging mechanism may be provided on only one of the first rotating body and the second rotating body. That is, the urging mechanism may be provided on at least one of the first rotating body and the second rotating body.
Next, examples of installation positions of the first rotating body and the second rotating body will be described with reference to
Since the units 134 are respectively provided on the upstream sides of the rollers 132 and 133, the positioning projection 61 can be stably positioned. Therefore, the reliability of the positioning of the intermediate transfer belt 24 can be improved.
As illustrated in
Although the first rotating body and the second rotating body are included in the belt positioning structure 30, the belt positioning structure according to the embodiment may be configured without the second rotating body. In this case, instead of the second rotating body, a non-rotating type regulating member that regulates movement of the belt in the direction away from the roller axis may be provided.
Although the positioning projection 61 is formed continuously in the length direction of the intermediate transfer belt 24 in the belt positioning structure 30, the configuration of the positioning projection is not particularly limited. For example, the positioning projections may be formed discontinuously in the length direction of the intermediate transfer belt. Specifically, the positioning projection may be a projection formed intermittently along the length direction of the intermediate transfer belt.
The image forming apparatus may be a monochrome image forming apparatus. The number of image forming parts is not limited. The image forming apparatus may include a plurality of printer units.
The belt positioning structure according to the present embodiment may be applied to a transfer belt used in a direct transfer type printer unit.
According to at least one embodiment described above, by providing the first rotating body that regulates the projection from moving in the first direction approaching the belt roller along the roller axis, the reliability of belt positioning can be improved.
While certain embodiments have been described, these embodiments have been presented by way of example only, and are not intended to limit the scope of the inventions. Indeed, the novel embodiments described herein may be embodied in a variety of other forms; furthermore, various omissions, substitutions and changes in the form of the embodiments described herein may be made without departing from the spirit of the inventions. The accompanying claims and their equivalents are intended to cover such forms or modifications as would fall within the scope and spirit of the inventions.
| Number | Name | Date | Kind |
|---|---|---|---|
| 6871038 | Fujiwara | Mar 2005 | B2 |
| 20060291913 | Hiroe | Dec 2006 | A1 |
| 20150277332 | Taira | Oct 2015 | A1 |
| 20160313677 | Oyama | Oct 2016 | A1 |
| Number | Date | Country |
|---|---|---|
| 2019-053257 | Apr 2019 | JP |
