JP6292474B2 - Belt device and image forming apparatus having the same - Google Patents

Description

  The present invention relates to a belt device including an endless belt member that is stretched around a plurality of support rotating bodies, and an image forming apparatus such as a copying machine, a printer, and a facsimile including the belt device.

  As an image forming apparatus using an electrophotographic process, a color image forming apparatus is known in which a toner image of each color formed on a latent image carrier is primarily transferred to an intermediate transfer member and then secondarily transferred to a sheet material. ing. Secondary transfer devices in this type of image forming apparatus include a roller transfer method and a belt transfer method. The roller transfer method is a method in which secondary transfer is performed while a sheet material is sandwiched and conveyed between an intermediate transfer member and a transfer roller. On the other hand, in the belt transfer system, the secondary transfer is performed while the sheet material is sandwiched and conveyed between an endless conveyance belt and an intermediate transfer member that are stretched between support rollers including the secondary transfer roller of the secondary transfer device. It is a method to perform. In the belt transfer method, the sheet material is held and conveyed by at least one secondary transfer belt portion on the upstream side and the downstream side in the sheet material conveyance direction where the sheet material is sandwiched between the intermediate transfer member. For this reason, the sheet material can be held and imparted with conveying force not only at the location where the sheet material is sandwiched between the intermediate transfer member but also at the upstream side and downstream side in the sheet material conveying direction. Therefore, the belt transfer method is generally preferable to the roller transfer method with respect to the stable conveyance of the sheet material.

  In this belt transfer system, as in a general belt device, the secondary transfer belt moves toward one end in the belt width direction (belt shift), or the belt meandering is repeated such that the belt shift toward each end in the belt width direction is repeated. A phenomenon that occurs may occur. Near the belt (including belt meandering) is an assembly size tolerance of the structure constituting the secondary transfer device, for example, the parallelism of the rotation shafts of the plurality of support rollers that support the secondary transfer belt and the outer diameter of the rollers. This is caused by unevenness in tension, non-uniform tension due to a change in peripheral length of the secondary transfer belt itself, and the like. Due to these causes, the secondary transfer belt travels in a state of being displaced in the belt width direction without traveling in a straight line, so that the belt is displaced in the displaced direction.

Conventionally, various belt deviation regulating means have been proposed in order to keep the movement range of the belt in the width direction due to the belt deviation within a certain regulation range.
For example, in Patent Document 1, if at least one of a plurality of support rollers that stretch an intermediate transfer belt or a secondary transfer belt is used as a tilting rotating body that can tilt, and the occurrence of belt deviation is detected. An axis inclination type belt deviation regulating means for moving the belt in a direction in which the steering roller is inclined to return the belt deviation is disclosed. The belt deviation regulating means disclosed in Patent Document 1 is provided with a detection means for detecting the occurrence of belt deviation, and controls the amount of inclination of the steering roller based on the detection result of the detection means.

  The above-mentioned Patent Document 1 does not mention cleaning of the surfaces of the intermediate transfer belt and the secondary transfer belt after transfer, but if necessary, a cleaning blade as a contact member for removing transfer residual toner. Further, it is conceivable to provide a seal member as a contact member for preventing leakage of waste toner. The cleaning blade comes into contact with the surface of the intermediate transfer belt or the secondary transfer belt so as to bite, and the seal member is also upstream of the intermediate belt or secondary transfer belt in the belt running direction of the cleaning portion by the cleaning blade. It is arranged so as to abut on the surface of the surface. However, in the belt device of Patent Document 1, the position of the belt member in the width direction orthogonal to the moving direction of the belt member is adjusted by inclining the steering roller. For this reason, for example, when one end side of the steering roller is excessively pushed up with respect to the other end side, the intermediate transfer belt and the secondary transfer belt are displaced upward with respect to the seal member, for example. As a result, the tip of the seal member is separated from the surface of the intermediate transfer belt or the secondary transfer belt, and a gap is generated between the tip of the seal member and the surface of the intermediate transfer belt or the secondary transfer belt. Then, there may be a problem that the removed waste toner is scattered from the gap to the outside of the seal member. Conversely, when the one end side is excessively pressed down relative to the other end side, the tip of the seal member is excessively pressed against the surface of the intermediate transfer belt or the secondary transfer belt, and the cleaning blade or seal member There is also a problem that the tip part of the metal wears unnecessarily, resulting in insufficient cleaning and sealing.

  The present invention has been made in view of the above-described problems, and an object of the present invention is to appropriately press the contact member against the surface of the belt member and to form a gap at the contact portion of the contact member with the belt member. It is an object of the present invention to provide a belt device capable of suppressing the occurrence of the above and an image forming apparatus including the belt device.

In order to achieve the above object, the invention of claim 1 includes an endless belt member that is stretched around a plurality of supporting rotating bodies, and one end side of at least one rotating shaft of the plurality of supporting rotating bodies. Displacement and tilting of at least one of the other end side allows the belt member to be moved in the belt width direction to correct the belt shift, and the upstream of the belt member in the running direction of the belt member. Excluding a winding region in a running direction of the belt member that is stretched between at least one of the support rotating body on the side and the downstream side and the tilting rotating body and wound around the support rotating body and the tilting rotating body. abuts against the surface of the tension portion of the belt member, the belt device including an abutment member fixed to the apparatus main body side, supporting rotator times without tilting of the plurality of supporting rotating bodies In the cross section orthogonal to the axis, the front end of the contact member on the belt side in a state where the belt member is assumed to be absent from the surface position taken by the surface of the belt member in the state where the contact member is not present. Winding of the belt member wound in the running direction from the contact portion of the contact member with the belt member according to the amount of biting of the contact member, which is an amount protruding toward the back side of the belt The fixing position of the abutting member is set so that the length of the tension portion to the end of the region changes, and the maximum value of the length is the length of the radius of the support rotating body. Is.

  According to the present invention, there is provided a belt device capable of appropriately pressing the contact member against the surface of the belt member and suppressing the occurrence of a gap at the contact portion between the contact member and the belt member, and the belt device. An image forming apparatus is provided.

1 is a schematic configuration diagram illustrating a printer according to an embodiment. It is a schematic diagram when the structure of the shaft inclination mechanism of the secondary transfer apparatus immediately after the assembly is viewed from the axial direction of the separation roller. It is a schematic diagram when the structure of the coaxial inclination mechanism after belt deviation regulation is seen from the axial direction of the separation roller. It is the schematic diagram which showed the structure of the coaxial tilting mechanism immediately after an assembly | attachment with the cut surface cut | disconnected along the rotating shaft of the separation roller. It is the schematic diagram which showed the structure of the coaxial tilting mechanism after belt deviation regulation with the cut surface cut | disconnected along the rotating shaft of the separation roller. FIG. 6 is an explanatory diagram of a belt shift in a secondary transfer belt. It is a perspective view of the shaft inclination member in a coaxial inclination mechanism. FIG. 3 is a perspective view of the secondary transfer device in a state where the secondary transfer belt is stretched with a predetermined tension. It is a schematic diagram explaining the structure of the secondary transfer apparatus seen from the axial direction. FIG. 6 is a schematic diagram for explaining the amount of biting of the inlet seal member into the surface of the secondary transfer belt. (A) is a schematic diagram for explaining the relationship between the amount of displacement of the separation roller and the amount of biting of the inlet seal member as viewed from the axial direction, and (b) is the secondary transfer at the contact point where the separation roller is tilted downward to the maximum. It is a schematic diagram explaining the relationship with the displacement amount of a belt. It is a perspective view of the modification of a secondary transfer apparatus. It is a schematic diagram which shows the structure of the secondary transfer apparatus seen from the axial direction.

Hereinafter, an embodiment in which the present invention is applied to a printer which is an electrophotographic image forming apparatus will be described with reference to the drawings.
FIG. 1 is a schematic configuration diagram illustrating a printer according to the present embodiment.
The printer is provided with four photoconductors 1a, 1b, 1c, and 1d arranged in the main body casing. Different color toner images are formed on the respective photoreceptors. Specifically, a black toner image, a magenta toner image, a cyan toner image, and a yellow toner image are formed on these photoreceptors 1a, 1b, 1c, and 1d, respectively. Note that each of the photoreceptors 1a, 1b, 1c, and 1d in the present embodiment is formed in a drum shape, but an endless belt-like photoreceptor that is wound around a plurality of rollers and driven to rotate can also be used.

  An intermediate transfer belt 51, which is an endless belt-like member, is disposed as an intermediate transfer member that is an image carrier, facing the four photosensitive members 1a, 1b, 1c, and 1d. The outer peripheral surfaces of the photoreceptors 1a, 1b, 1c, and 1d are in contact with the outer peripheral surface of the intermediate transfer belt 51, respectively. The intermediate transfer belt 51 according to the present embodiment is wound and stretched around a support roller (support rotary body) such as a tension roller 52, a drive roller 53, a repulsive roller 54, and an entrance roller 55. A driving roller 53 that is one of these support rollers is rotationally driven by a driving source (not shown), and the intermediate transfer belt 51 travels in the direction of arrow A in FIG.

  The intermediate transfer belt 51 may have a multilayer structure or a single layer structure. When the belt is composed of a multilayer structure, for example, a base layer is formed of a less stretched fluororesin, PVDF sheet, or polyimide resin, and the belt outer peripheral surface is composed of a smooth coat layer such as a fluororesin. preferable. On the other hand, when a belt having a single layer structure is used, a material such as PVDF, PC, or polyimide is preferably used.

  The configuration and operation for forming each color toner image on each photoconductor 1a, 1b, 1c, 1d and the configuration and operation for primary transfer of each color toner image onto the intermediate transfer belt 51 are substantially the same and formed. Only the color of each color toner image is different. Therefore, hereinafter, a configuration and operation for forming a black toner image on the black photoconductor 1a and primarily transferring the toner image onto the intermediate transfer belt 51 will be described, and description of other colors will be omitted.

  The black photoconductor 1a is driven to rotate counterclockwise in FIG. The surface potential of the photoconductor 1a is initialized by irradiating the outer peripheral surface of the photoconductor 1a with light from a static eliminator (not shown). The initialized outer peripheral surface of the photoconductor is uniformly charged to a predetermined polarity (in this embodiment, a negative polarity) by the charging device 8a. The photosensitive member outer peripheral surface thus charged is irradiated with a light-modulated laser beam L emitted from an exposure device (not shown), whereby an electrostatic latent image is formed on the outer peripheral surface of the photosensitive member 1a. . In the present embodiment, the exposure apparatus that emits the laser beam L is configured by a laser writing apparatus. However, for example, an exposure apparatus having an LED array and an image forming unit may be used. The electrostatic latent image formed on the photoconductor 1a is visualized as a black toner image when passing through a developing area facing the developing device 10a.

  On the inner peripheral surface side of the intermediate transfer belt 51, a primary transfer roller 11a is disposed at a position facing the photoreceptor 1a. When the primary transfer roller 11 a contacts the inner peripheral surface of the intermediate transfer belt 51, an appropriate primary transfer nip is ensured between the photoreceptor 1 a and the intermediate transfer belt 51. The primary transfer roller 11a is applied with a primary transfer voltage having a polarity opposite to the toner charging polarity of the toner image formed on the photoreceptor 1a (plus polarity in the present embodiment). As a result, a primary transfer electric field is formed between the photoreceptor 1a and the intermediate transfer belt 51, and the toner image on the photoreceptor 1a is statically transferred onto the intermediate transfer belt 51 that is driven to rotate in synchronization with the photoreceptor 1a. Electrically primary transferred. The transfer residual toner adhering to the outer peripheral surface of the photoconductor 1a after the toner image is primarily transferred to the intermediate transfer belt 51 is removed by the cleaning device 12a, and the outer peripheral surface of the photoconductor 1a is cleaned.

  In the full color mode using all four color toner images, magenta toner images, cyan toner images, and yellow toner images are similarly formed on the photoconductors 1b, 1c, and 1d of other colors. These color toner images are sequentially primary-transferred so as to be superimposed on the black toner image primarily transferred onto the intermediate transfer belt 51.

  On the other hand, in the black monochromatic mode, the primary transfer rollers 11b, 11c, and 11d are separated from the photoreceptors 1b, 1c, and 1d by a contact / separation mechanism (not shown) to thereby provide the photoreceptors 1b, 1c, magenta, cyan, and yellow. 1 d is separated from the intermediate transfer belt 51. Only the black toner image is primarily transferred to the intermediate transfer belt 51 while only the black photosensitive member 1 a is in contact with the intermediate transfer belt 51.

  As shown in FIG. 1, a paper feeding device 14 is disposed at the lower part of the printer body. The sheet feeding device 14 feeds the transfer sheet P as a sheet material in the direction of the arrow B in the drawing by the rotation of the sheet feeding roller 15. The transferred transfer paper P is subjected to a contact between the intermediate transfer belt 51 wound around the repulsive roller 54 at a predetermined timing by the registration roller pair 16 and the secondary transfer belt 61 disposed opposite thereto. It is fed to the secondary transfer nip that is in contact. At this time, a predetermined secondary transfer voltage is applied to the repulsive roller 54, whereby the toner image on the intermediate transfer belt 51 is secondarily transferred to the transfer paper P.

  The secondary transfer belt 61 as an endless belt member is stretched and supported by a separation roller 63 that is an inclined rotator as a second support rotator and a secondary transfer roller 62 as a second support rotator. Yes. In the present embodiment, the secondary transfer roller 62 is driven to rotate as a driving roller, so that the secondary transfer belt 61 travels in the direction of arrow C in FIG. The transfer paper P onto which the toner image has been secondarily transferred is conveyed as the secondary transfer belt 61 travels while being electrostatically attracted to the outer peripheral surface of the secondary transfer belt 61. The transfer paper P is separated from the outer peripheral surface of the secondary transfer belt 61 by the curvature of the portion of the secondary transfer belt 61 wound around the separation roller 63, and is disposed downstream of the secondary transfer belt 61 in the transfer paper transport direction. It is further conveyed downstream in the transfer sheet conveying direction by the conveying belt 17. The conveyor belt 17 is stretched between an inlet roller 17A as a driving roller as an inlet rotator and a driven roller 17B as a driven rotator. When the transfer paper P passes through the fixing device 18, the toner image on the transfer paper P is fixed to the transfer paper P by the action of heat and pressure. The transfer paper P that has passed through the fixing device 18 is discharged out of the apparatus through a pair of paper discharge rollers 19 provided in the paper discharge unit.

  Further, the transfer residual toner adhering to the intermediate transfer belt 51 after the toner image is secondarily transferred is removed by the belt cleaning device 20. In the belt cleaning device 20 according to the present embodiment, a blade-shaped cleaning blade 21 made of urethane or the like is used, and the cleaning blade 21 is brought into contact with the traveling direction of the intermediate transfer belt 51 from the counter direction. . Various types of belt cleaning device 20 can be used as appropriate, and for example, the cleaning device may be an electrostatic type.

Next, the configuration and operation of the belt deviation regulating means in the secondary transfer device 60 including the secondary transfer belt 61 will be described.
The belt shift restricting means of the secondary transfer device 60 in this embodiment is an axis inclination method, and the rotation shaft 63a of the separation roller 63, which is one of the support rollers that stretch the secondary transfer belt 61, is inclined. It is configured by a shaft tilt mechanism 70 that regulates the belt shift range of the secondary transfer belt 61 within a predetermined regulation range.

  FIG. 2 is a schematic diagram of the configuration of the shaft tilting mechanism of the secondary transfer device 60 immediately after assembly when viewed from the axial direction of the separation roller 63. FIG. 3 is a schematic diagram of the configuration of the shaft tilt mechanism after the belt shift restriction is viewed from the axial direction of the separation roller 63.

  A bearing member (not shown) is attached to each end of the rotary shaft of the secondary transfer roller 62 of the present embodiment. Each bearing member is held by two frames (shaft end holding members) 68 of the secondary transfer device 60 positioned on both ends of the secondary transfer roller 62 in the axial direction. As a result, the secondary transfer roller 62 is rotatably supported with respect to the frame 68.

  Further, each end portion of the rotation shaft of the separation roller 63 of this embodiment is attached to a slide bearing portion 65 respectively held by two rotation shaft support arms 64 disposed further outside in the axial direction than the frame 68. Thereby, the separation roller 63 is rotatably supported with respect to the rotating shaft support arm 64.

  Each rotary shaft support arm 64 is rotatably attached to each end portion of the rotary shaft 62a of the secondary transfer roller 62, and an arm spring 66 having one end fixed to the frame 68 of the secondary transfer device 60. Is urged clockwise in FIG. When the secondary transfer belt 61 is not belt-developed and immediately after assembly, the end of the rotary shaft support arm 64 abuts the end (not shown) of the frame 68 by the urging force of the arm spring 66, The rotational position of the rotary shaft support arm 64 is held at the abutting position (FIG. 2).

  As shown in FIGS. 2 and 3, each rotary shaft support arm 64 holds a slide bearing portion 65 that supports the separation roller 63 so as to be slidable in the radial direction from the rotation center of the rotary shaft support arm 64. Yes. The slide bearing portion 65 is urged toward the radially outer side in the radial direction from the rotation center of the rotary shaft support arm 64 by a tension spring 67 with respect to the rotary shaft support arm 64. As a result, the separation roller 63 always receives a biasing force in a direction away from the secondary transfer roller 62, and a predetermined tension (tension) is applied to the secondary transfer belt 61 stretched between the separation roller 63 and the secondary transfer roller 62. ).

FIG. 4 is a schematic diagram showing the configuration of the shaft tilt mechanism 70 of the secondary transfer device 60 with a cut surface cut along the rotation shaft 63 a of the separation roller 63.
The separation roller 63 is provided with a belt shift detection member 71 and a shaft inclination member 72 that constitute an axial displacement member on a rotation shaft 63 a between the separation roller 63 and the slide bearing portion 65. The belt shift detection member 71 includes a flange portion 71 a that contacts the end portion of the secondary transfer belt 61. When the secondary transfer belt 61 moves in the belt width direction and the end of the secondary transfer belt 61 comes into contact with the flange portion 71a, the belt deviation detecting member 71 receives the force to the rotation shaft 63a of the separation roller 63. And move outward in the axial direction. When the belt shift detection member 71 moves axially outward along the rotation shaft 63a, the shaft tilt member 72 disposed further outside the rotation shaft 63a with respect to the belt shift detection member 71 also moves along the rotation shaft 63a. Move axially outward.

  Further, a contact portion 68a of a frame 68 that is a fixed member is in contact with the inclined surface 72a of the shaft inclined member 72 from the outside in the axial direction of the rotating shaft 63a. At this time, the end portion of the rotation shaft 63a of the separation roller 63 provided with the shaft inclination member 72 is supported by the rotation shaft support arm 64 urged by the arm spring 66 via the slide bearing portion 65. Therefore, the urging force toward the upper side in FIG. 4 is received. Therefore, if the end portion of the secondary transfer belt 61 is not in contact with the flange portion 71 a of the belt deviation detecting member 71, the biasing force of the arm spring 66 continues to the lower end of the inclined surface 72 a of the shaft inclined member 72. The stopper surface 68b of the frame 68 is in contact with the stopper surface 72b. At this contact position, the contact position between the inclined surface 72a of the shaft inclined member 72 and the contact portion 68a of the frame 68 is regulated. That is, the abutting portion 68 a of the frame 68 is held in a state where it abuts on the lower end portion of the inclined surface 72 a of the shaft inclined member 72. The contact position between the shaft inclined member 72 and the frame 68 is regulated at the position where the stopper surface 68c of the frame 68 contacts the stopper surface 72c.

  From this state, when the secondary transfer belt 61 receives a force that moves outward in the belt width direction, and the belt shift detection member 71 and the shaft tilt member 72 move outward along the rotation shaft 63a, the shaft tilt member 72 is moved. The abutting portion 68a of the frame 68 relatively moves along the inclined surface 72a. Thereby, the contact position between the inclined surface 72a of the shaft inclined member 72 and the contact portion 68a of the frame 68 is displaced to the upper side of the inclined surface 72a. As a result, one end portion of the rotation shaft 63a of the separation roller 63 on the axial end side in the direction in which the secondary transfer belt 61 moves is pushed down against the urging force of the arm spring 66 as shown in FIG. . At this time, the end portion of the rotation shaft 63a of the separation roller 63 opposite to the direction in which the secondary transfer belt 61 moves is such that the end portion of the secondary transfer belt 61 contacts the flange portion 71a of the belt shift detection member 71. Not. For this reason, as shown in FIG. 4, the abutting portion 68 a of the frame 68 is held in a state where it abuts on the lower end portion of the inclined surface 72 a of the shaft inclined member 72. Thereby, the other end side of the rotating shaft 63a of the separation roller 63 is positioned relatively higher than the one end side of the rotating shaft 63a in a pressed state with respect to the moving direction of the secondary transfer belt 61. It becomes. Therefore, the rotation shaft 63a of the separation roller 63 is inclined.

  In this way, as the rotation shaft 63a of the separation roller 63 is inclined, the moving speed of the secondary transfer belt 61 in the belt width direction gradually decreases, and finally the secondary transfer belt 61 is reverse in the belt width direction. To move on. As a result, the position in the width direction of the secondary transfer belt 61 is gradually returned, and the secondary transfer belt 61 can travel stably at the position in the width direction where the belt shift converges. When the belt transfer of the secondary transfer belt 61 occurs in the opposite direction, the rotation shaft 63a is inclined by the shaft inclination member 72 on the belt moving direction side.

Here, the principle by which the belt can be returned by tilting the rotation shaft 63a of the separation roller 63 will be described.
FIG. 6 is an explanatory diagram of the belt shift in the secondary transfer belt. The secondary transfer belt 61 is moved in the direction of arrow A in FIG. 6 by the rotation of the rotation shaft 63a of the separation roller 63.
Assuming that the secondary transfer belt 61 is a rigid body, attention is paid to an arbitrary point on the secondary transfer belt 61 before entering the separation roller 63 (here, a point E on the belt end). If the secondary transfer belt 61 stretched between the two rollers 62 and 63 is in a completely horizontal or parallel state, the point E on the secondary transfer belt 61 immediately before entering the separation roller 63 and the separation are separated. There is no deviation in the position of the separation roller 63 in the rotational axis direction with respect to the point E ′ corresponding to the point E on the secondary transfer belt 61 immediately after the roller 63 is removed. In this case, no belt shift occurs in the secondary transfer belt 61.

  On the other hand, when the rotation shaft 63a of the separation roller 63 is inclined with respect to the rotation shaft 62a of the secondary transfer roller 62, if the inclination angle is α, the point E on the secondary transfer belt 61 is the separation roller 63. 6, as shown in FIG. 6, it is displaced by about tan α to a point E ′ corresponding to the point E in the + Z direction in FIG. 6 in the rotation axis direction of the separation roller 63. Therefore, if the rotation shaft 63 a of the separation roller 63 is inclined by the inclination angle α with respect to the rotation shaft 62 a of the secondary transfer roller 62, the secondary transfer belt 61 is rotated in accordance with the rotation of the separation roller 63. The position of 61 in the belt width direction can be moved by approximately tanα.

  The shift amount (moving speed in the belt width direction) of the secondary transfer belt 61 is proportional to the inclination angle α. That is, the larger the inclination angle α, the larger the amount of deviation of the secondary transfer belt 61, and the smaller the angle, the smaller the amount of deviation of the belt. By inclining the rotation shaft 63a of the separation roller 63 using the principle of belt deviation as described above, it is possible to generate a belt deviation to return the belt deviation. Then, the secondary transfer belt 61 is located at a position where the belt shift originally generated in the secondary transfer belt 61 and the reverse belt shift of the secondary transfer belt 61 generated by the rotation of the rotation shaft 63a of the separation roller 63 are balanced. The belt side of the belt 61 can be converged. Even if a belt shift to either one of the secondary transfer belt 61 running at the balance position occurs, the rotation shaft 63a of the separation roller 63 is inclined according to the belt shift, so that again, The belt shift of the secondary transfer belt 61 converges at another balance position.

  As described above, according to the shaft tilting mechanism 70 of the secondary transfer device 60 in the present embodiment, a tilt corresponding to the amount of movement of the secondary transfer belt 61 in the belt width direction is given to the rotation shaft 63a of the separation roller 63. Thus, the belt shift of the secondary transfer belt 61 can be converged at an early stage. In addition, the driving force for tilting the rotating shaft 63a of the separation roller 63 uses a force that moves the secondary transfer belt 61 in the belt width direction, and thus has a simple configuration that does not require a driving source such as a motor. realizable.

Next, the configuration of the shaft inclined member 72 will be described.
FIG. 7 is a perspective view of the shaft inclined member 72 in the present embodiment.
The shaft inclined member 72 of the present embodiment has a configuration in which a protrusion having an inclined surface 72a is formed on the outer peripheral surface of the cylindrical main body. The inclined surface 72a is formed of a curved surface formed so as to form a part of a conical circumferential surface centering on the central axis of the cylindrical main body. There are two reasons why the inclined surface 72a is formed of a curved surface. The first reason is to prevent the tilt angle of the separation roller 63 from changing even if the shaft tilting member 72 slightly rotates around the rotation shaft 63a of the separation roller 63. The second reason is that the contact with the contact portion 68a of the frame 68 is made close to point contact, and friction at the contact point is reduced, so that the end portion of the secondary transfer belt 61 and the belt deviation detecting member 71 are not affected. This is because the contact pressure is reduced, the deterioration of the end of the secondary transfer belt 61 is suppressed, and the life of the secondary transfer belt 61 is extended. In the present embodiment, the inclination angle β of the inclined surface 72a with respect to the rotation shaft 63a is 30 °, and the material of the shaft inclined member 72 is POM (polyacetal), but is not limited thereto.

  Further, since bending stress repeatedly acts on the end portion of the secondary transfer belt 61 due to contact with the belt deviation detecting member 71, breakage such as a crack is likely to occur. For this reason, it is preferable to apply a reinforcing tape to the outer peripheral surface or inner peripheral surface of the secondary transfer belt 61 over the entire belt.

An example of specific configurations of the separation roller 63 and the secondary transfer belt 61 of the present embodiment will be shown below.
Separation roller outer diameter: φ15 [mm]
Material of separation roller: Aluminum Material of secondary transfer belt: Polyimide Young's modulus of secondary transfer belt: 3000 [MPa]
Folding resistance of secondary transfer belt by MIT weather resistance test: 6000 [times]
Secondary transfer belt thickness: 80 [μm]
Secondary transfer belt linear velocity: 352 [mm / s]
Belt tension: 0.9 [N / cm]
In addition, it is based on JIS-P8115 as a folding-resistant frequency measurement method by a MIT weather resistance test. As measurement conditions, a sample having a width of 15 [mm] was measured under the conditions of a load of 1 [kgf], a bending angle of 135 [degrees], and a bending speed of 175 [times / minute].

Next, the configuration of the secondary transfer apparatus that is a characteristic part of the present invention will be described.
FIG. 8 is a perspective view of the secondary transfer device 60 in a state where the secondary transfer belt 61 is stretched with a predetermined tension. As shown in FIG. 8, the secondary transfer belt 61 receives a biasing force in a direction in which the separation roller 63 separates from the secondary transfer roller 62 due to the biasing force of the tension spring 67 of the rotary shaft support arm 64. For this reason, it is stretched with a predetermined tension. The frame 68 is provided with a notch (not shown) as a second holding part for detachably holding a bearing member (not shown) attached to the end of the rotary shaft 62a of the secondary transfer roller 62. Yes. Further, the end of the rotating shaft 63a of the separation roller 63 is detachably held by the frame 68. A bearing member (not shown) provided at each end of the rotating shaft of the secondary transfer roller 62 and a shaft inclined member (not shown) provided at each end of the rotating shaft of the separation roller 63 are held by the frame 68, respectively. Is done.

  FIG. 9 is a schematic diagram illustrating the configuration of the secondary transfer device 60 as viewed from the axial direction. As shown in FIG. 9, a cleaning device 80 is disposed below the secondary transfer device 60. The cleaning blade 81 is in contact with the traveling direction of the secondary transfer belt 61 in the direction indicated by the arrow A in FIG. Thereby, the transfer residual toner on the surface of the secondary transfer belt 61 is removed. The removed toner falls by its own weight and is stored in the toner storage unit. In order to prevent the toner dropped from the secondary transfer belt 61 from scattering, an inlet seal member 82 as a seal member is disposed on the upstream side in the running direction from the portion where the secondary transfer belt 61 is attached to the secondary transfer roller 62. Yes. The inlet seal member 82 is fixed to a predetermined portion of the housing 83 constituting the entire secondary transfer device 60 so that the state of contact with the surface of the secondary transfer belt 61 can be maintained in the tilting range of the separation roller 63. ing. In addition, although the material of the inlet seal member 82 usually uses a sheet material such as polyurethane, it is not limited to this.

  When a belt shift occurs in the secondary transfer belt 61, an inclination corresponding to the amount of movement of the secondary transfer belt 61 in the belt width direction is given to the rotating shaft 63a of the separation roller 63 as described above, and the secondary transfer belt 61 Converge the belt. At this time, the rotation shaft 63a of the separation roller 63 is displaced downward in FIG. 9, and the secondary transfer belt 61 suspended on the separation roller 63 is displaced downward along with the displacement. In this embodiment, the amount of biting when the rotation shaft 62a of the secondary transfer roller 62 and the rotation shaft 63a of the separation roller 63 are substantially parallel to each other, that is, when the separation roller 63 is not tilted, is the initial biting amount. That's it. The amount of biting is the secondary transfer relative to the surface position taken by the surface of the secondary transfer belt 61 on the assumption that the inlet seal member 82 does not exist in the cross section orthogonal to the rotation shaft 62a of the secondary transfer roller 62. It is defined as the amount by which the belt-side tip of the inlet seal member 82 protrudes toward the back side of the belt under the assumption that the belt 61 does not exist. Then, it was found that when the initial biting amount was less than 1 [mm], the sealing property of the inlet seal member 82 was insufficient and the waste toner leaked. When the initial bite amount becomes negative, a gap is generated between the surface on one end side of the secondary transfer belt 61 and the front end of the inlet seal member 82, and waste toner leaks from the gap to the outside of the inlet seal member 82. Will be scattered and contaminated in the plane. Therefore, the fixing position of the inlet seal member 82 is set so that the initial bite amount D is 1 [mm] or more.

  When the belt shift occurs in the secondary transfer belt 61, when the rotation shaft 63a of the separation roller 63 on the side where the secondary transfer belt 61 is displaced is displaced downward, the secondary transfer belt 61 wound around the rotation shaft 63a is moved. Displaces downward. If the amount of downward displacement of the rotation shaft 63a of the separation roller 63 is excessively inclined, the amount of biting of the inlet seal member 82 into the surface of the secondary transfer belt 61 increases excessively, and the secondary transfer belt at the inlet seal member 82 increases. The waste toner on 61 is scraped off. As a result, the waste toner is dropped from the upstream side in the belt traveling direction from the contact position of the inlet seal member 82 with the secondary transfer belt 61. In the long term, waste toner accumulates, causing toner scattering from the secondary transfer device 60 into the image forming apparatus. In order to prevent this, as shown in FIG. 10, it has also been found that the amount D of the entrance seal member 82 biting into the surface of the secondary transfer belt 61 needs to be 2 [mm] or less. Therefore, the entrance seal is set so that the amount of biting D between the surface of the secondary transfer belt 61 and the belt side tip of the entrance seal member 82 is 2 [mm] or less within the displacement range of the rotation shaft 63a of the separation roller 63. The fixed position of the member 82 was set.

  FIG. 11A shows the amount of downward displacement of one end side of the rotation shaft 63a of the separation roller 63 and the surface position on one end side of the secondary transfer belt 61 at the contact point on one end side of the inlet seal member 82. It is a schematic diagram explaining the relationship with a displacement amount. FIG. 11B is a schematic diagram for explaining the relationship between the downward tilt amount of one end side of the rotating shaft 63a of the separation roller 63 and the displacement amount of the surface position on the one end side of the secondary transfer belt at the contact portion. FIG. The broken line in FIG. 11B shows the cross section of the secondary transfer belt 61 at the contact point 82a when the rotary shaft 63a of the separation roller 63 is not displaced in the cross section orthogonal to the rotary shaft 62a of the secondary transfer roller 62. The surface position on one end side is shown, and the solid line in FIG. 11B shows the surface position on one end side of the secondary transfer belt 61 at the contact portion 82a when the one end side of the rotating shaft 63a of the separation roller 63 is displaced downward. Indicates.

  As shown in FIGS. 11A and 11B, one end of the winding area of the secondary transfer roller 62 around the secondary transfer belt 61 and one end of the winding area of the separation roller 63 around the secondary transfer belt 61. Let A be the interval. The length from the contact portion 82a of the inlet seal member 82 to the secondary transfer belt 61 to one end of the winding region of the secondary transfer roller 62 around the secondary transfer belt 61 is defined as B. From the surface position of the secondary transfer belt 61 in the cross section orthogonal to the rotation shaft 62a of the secondary transfer roller 62 when the rotation shaft 62a of the secondary transfer roller 62 and the rotation shaft 63a of the separation roller 63 are substantially parallel to each other. The amount of displacement of the separation roller 63 in the downward direction of the rotation shaft 63a is X. The displacement amount of the surface position on one end side at the contact portion 82a of the secondary transfer belt 61, which becomes a length B from one end portion of the winding area of the secondary transfer roller 62 with the secondary transfer belt 61, is W. The displacement amount W is obtained by X · B / A. When the rotary shaft 63a of the separation roller 63 is displaced downward by the above-mentioned displacement amount X, the amount of biting D at the front end of the inlet seal member 82 to the one end side surface at the contact portion 82a of the secondary transfer belt 61 is The initial amount of biting is obtained by adding the amount of displacement W of the surface position on one end side at the contact portion 82a of the secondary transfer belt 61 obtained by X · B / A. Therefore, the fixing position of the inlet seal member 82 is set so that the amount of biting D when the rotation shaft 63a of the separation roller 63 is displaced downward by the displacement amount X is equal to or less than 2 [mm] described above.

(Modification)
Next, a modification of the secondary transfer device in the above embodiment (hereinafter, this modification is referred to as “modification”) will be described.
FIG. 12 is a perspective view of a modification of the secondary transfer device. FIG. 13 is a schematic diagram showing the configuration of the secondary transfer apparatus viewed from the axial direction. As shown in FIG. 12, the inventors observed changes in the surface of the secondary transfer belt 61 when using the secondary transfer device 60. As a result, the inventors observed that the secondary transfer belt 61 was inclined with respect to the traveling direction of the secondary transfer belt 61. It was confirmed that a wave 91 was generated. When this undulation 91 occurs at the contact position of the inlet seal member 82 with the secondary transfer belt 61, the end of the inlet seal member 82 is separated from the surface of the secondary transfer belt 61. In this case, a gap is generated between the surface of the secondary transfer belt 61 and the toner leaks out of the entrance seal member 82 from the gap and is scattered in the apparatus. Further, a change in the surface of the secondary transfer belt 61 in the region (L ₂ ) away from both sides of the winding region (L ₁ ) where the secondary transfer belt 61 is wound around the secondary transfer roller 62 was observed. Observation was performed using a plurality of secondary transfer rollers 62 with increased and decreased radii. As a result of these observations, the region (L ₂ ) in which no undulation has occurred changes according to the radius of the secondary transfer roller 62, and the region (L ₂ ) becomes the radius of the secondary transfer roller 62. It was confirmed that they were almost the same.

As shown in FIG. 13, the contact position of the inlet seal member 82 is disposed in the region (L ₂ ) having a predetermined length from both sides of the winding region (L ₁ ). Further, the length of the region (L ₂ ) is defined as the radius of the secondary transfer roller 62. As a result, the generation of a gap between the surface of the secondary transfer belt 61 and the inlet seal member 82 due to the undulation of the secondary transfer belt 61 can be suppressed, and the waste toner leaks from the cleaning device 80 and scatters in the machine. This can be suppressed. The inlet seal member 82 is attached to the secondary transfer device 60 so that the maximum value of the length B of the secondary transfer roller 62 to the end of the contact portion with the secondary transfer belt 61 is equal to the radius of the secondary transfer roller 62. Secure to the chassis. As a result, toner scattering from the secondary transfer device 60 to the image forming apparatus can be stably suppressed.

  In this embodiment, the belt device is applied to the secondary transfer device 60. However, another endless belt member such as the intermediate transfer belt 51 is used and a tilting roller for correcting the belt shift is provided. The same can be applied to the belt device.

What has been described above is merely an example, and the present invention has a specific effect for each of the following modes.
(Aspect A)
A belt member such as an endless secondary transfer belt 61 that runs while being stretched around a plurality of support rotating bodies such as the secondary transfer roller 62 and the separation roller 63, and one end of at least one rotating shaft of the plurality of support rotating bodies. A tilting rotator such as a separation roller 63 that corrects a belt shift in which the belt member moves in the belt width direction by displacing and tilting at least one of the side and the other end side, and a belt member with respect to the tilting rotator The cleaning blade 81, the inlet seal member 82, and the like fixed to the apparatus main body are in contact with the surface of the belt member between at least one of the upstream and downstream support rotators and the tilting rotator in the traveling direction. In the belt device provided with the contact member, the cleaning blade 81 and the inlet seal member 82 contact the surface of the secondary transfer belt 61 in the tilting range of the separation roller 63. Fixing the cleaning blade 81 and the inlet seal member 82 at a position capable of maintaining the state of.
According to this, as described in the above embodiment, the cleaning blade 81 and the inlet seal member 82 are maintained in a state where the cleaning blade 81 and the inlet seal member 82 are in contact with the surface of the secondary transfer belt 61. The front end of the belt is not separated from the surface of the secondary transfer belt 61, and the cleaning performance and sealing performance can be maintained. Further, since the belt-side tips of the cleaning blade 81 and the inlet seal member 82 do not excessively bite into the surface of the secondary transfer belt 61, unnecessary wear on the belt-side tips of the cleaning blade 81 and the inlet seal member 82 can be suppressed, Cleaning property and sealing property can be stably maintained. As a result, the state where the cleaning blade 81 and the entrance seal member 82 are in contact with the surface of the secondary transfer belt 61 is appropriately maintained. Therefore, the contact member can be appropriately pressed against the surface of the belt member, and the generation of a gap at the contact portion between the contact member and the belt member can be suppressed.

(Aspect B)
In (Aspect A), it is assumed that the cleaning blade 81 and the inlet seal member 82 do not exist in a cross section orthogonal to the rotation axis of the supporting rotating body such as the secondary transfer roller 62 that does not tilt among the plurality of supporting rotating bodies. The amount of the front end of the cleaning blade 81 and the inlet seal member 82 projecting toward the back side of the belt with the assumption that the secondary transfer belt 61 does not exist with respect to the surface position taken by the surface of the secondary transfer belt 61. The fixing position of the cleaning blade 81 and the inlet seal member 82 was set so that the amount of biting of the cleaning blade 81 and the inlet seal member 82 was 1 [mm] or more within the tilting range of the separation roller 63. According to this, as described in the above-described embodiment, it is possible to prevent the distal end portions of the cleaning blade 81 and the inlet seal member 82 from being separated from the surface of the secondary transfer belt 61. Thereby, the cleaning performance by the cleaning blade 81 and the sealing performance by the inlet seal member 82 can be maintained.

(Aspect C)
In (Aspect A) or (Aspect B), the cleaning blade 81 and the inlet seal member are adjusted so that the amount of biting of the cleaning blade 81 and the inlet seal member 82 is 2 mm or less within the tilting range of the separation roller 63. 82 fixed positions were set. According to this, as described in the above embodiment, the belt-side tips of the cleaning blade 81 and the inlet seal member 82 do not excessively bite into the surface of the secondary transfer belt 61, so the cleaning blade 81 and the inlet seal member 82. Unnecessary wear at the belt end can be suppressed, and the cleaning performance and sealing performance can be stably maintained.

(Aspect D)
(Embodiment A) ~ (embodiment C) in the secondary transfer roller 62 or the separation roller 63 and the secondary transfer from both sides of the winding can with regions in the running direction of which the secondary transfer belt 61 wound around the roller 62 or the separation roller 63 The fixing positions of the cleaning blade 81 and the inlet seal member 82 are set so as to contact the secondary transfer belt 61 in the contact region up to the place separated by the length of the radius of the contact. According to this, as described in the above embodiment, the belt device is used that stretches the endless secondary transfer belt 61 by the two rotating bodies of the secondary transfer roller 62 and the separation roller 63 and moves the endless endlessly. The change in the surface of the secondary transfer belt 61 was observed. As a result, no change in the surface of the secondary transfer belt 61 was observed in the contact area. A cleaning blade 81 and an inlet seal member 82 are provided so as to contact the secondary transfer belt 61 in the contact area. As a result, generation of a gap between the surface of the secondary transfer belt 61 and the tip of the cleaning blade 81 or the inlet seal member 82 and unnecessary wear on the belt side tip of the cleaning blade 81 or the inlet seal member 82 can be suppressed. . Thereby, the state which contact | abutted on the surface of the belt member of a contact member is maintained.
it can.

(Aspect E)
In an image forming apparatus that forms an image on the sheet material by using a belt device including an endless belt member that supports an image or a sheet material on which an image is recorded on an outer peripheral surface, The belt device according to any one of Aspects A) to (Aspect D) is used. According to this, as described in the above embodiment, it is possible to realize an image forming apparatus in which image disturbance and jamming are suppressed.

(Aspect F)
In (Embodiment E), primary transfer rollers 11a, 11b, 11c, and 11d that primarily transfer an image formed on a latent image carrier such as the photoreceptors 1a, 1b, 1c, and 1d to an intermediate transfer member such as the intermediate transfer belt 51. Primary transfer means and the like, and secondary transfer means such as a secondary transfer device 60 that secondary-transfers the image primarily transferred onto the intermediate transfer member onto the sheet material P. The secondary transfer means The image on the intermediate transfer member is secondarily transferred onto the sheet material carried and conveyed on the outer peripheral surface of the transfer belt 61. According to this, as described in the above embodiment, it is possible to suppress image disturbance and jamming in an image forming apparatus that employs an intermediate transfer method.

DESCRIPTION OF SYMBOLS 1 Photoconductor 11 Primary transfer roller 51 Intermediate transfer belt 60 Secondary transfer device 61 Secondary transfer belt 62 Secondary transfer roller 62a Rotating shaft 62b Bearing member 63 Separating roller 63a Rotating shaft 64 Rotating shaft support arm 65 Slide bearing portion 66 Arm spring 67 Tension spring 68 Frame 68a Abutting portion 68b Stopper surface 68c Stopper surface 70 Axis tilting mechanism 71 Belt deviation detecting member 71a Flange 72 Axis tilting member 72a Inclined surface 72b Stopped surface 72c Stopped surface 80 Cleaning device 81 Cleaning blade 82 Inlet Seal member 83 housing

JP 2012-103286 A

Claims (5)

An endless belt member that runs while being stretched around a plurality of support rotating bodies, and at least one of one end side and the other end side of at least one rotating shaft of the plurality of support rotating bodies is displaced and tilted. A tilting rotator that corrects a belt shift in which the belt member moves in the belt width direction, and at least one of the upstream and downstream support rotators in the running direction of the belt member with respect to the tilting rotator and the tilting rotation On the side of the apparatus main body, which is in contact with the surface of the tension portion of the belt member excluding the winding region in the running direction of the belt member that is stretched between the body and wound around the support rotating body and the tilting rotating body In a belt device provided with a fixed contact member,
The belt member is present with respect to the surface position taken by the surface of the belt member on the assumption that the contact member does not exist in a cross section orthogonal to the rotation axis of the support rotating body that does not tilt among the plurality of supporting rotating bodies. In the state where it is assumed that the contact member is not supported, the support member is supported from the contact portion of the contact member with the belt member in accordance with the amount of biting of the contact member, which is an amount by which the belt-side tip of the contact member protrudes to the belt back surface side. The length of the tension portion to the end of the winding region in the traveling direction of the belt member wound around the rotating body is changed, and the maximum value of the length is the length of the radius of the supporting rotating body. A belt device characterized in that a fixed position of a contact member is set . The belt device according to claim 1, wherein
Biting amount of pre Symbol abutment member, in the tilting range of the tilting rotary body, 1 so that the [mm] or more, the belt apparatus characterized by setting the fixing position of the abutment member. The belt device according to claim 1 or 2,
The belt device according to claim 1, wherein a fixed position of the contact member is set so that a biting amount of the contact member is 2 [mm] or less within a tilting range of the tilting rotating body . Using a belt device including an endless belt member supported on the outer peripheral surface of the sheet material images or image is recorded, the image in an image forming apparatus which forms on the sheet material,
Examples belt device, an image forming apparatus which comprises using a belt device according to any one of claims 1-3. The image forming apparatus according to claim 4 .
Primary transfer means for primarily transferring an image formed on the latent image carrier to an intermediate transfer member;
Secondary transfer means for secondary transfer of the image primarily transferred onto the intermediate transfer member to the sheet material;
The image forming apparatus, wherein the secondary transfer unit secondarily transfers an image on the intermediate transfer member onto a sheet material carried on an outer peripheral surface of the belt member.

Images