JP2016200766A - Belt device, transfer device, and image forming apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a belt device that comprises belt skew regulation means which hardly interfere with surrounding components and can control belt skew of a belt member over time, and to provide a transfer device and an image forming apparatus.SOLUTION: A belt device 60 comprises: a belt member 61 that runs while stretched by a plurality of support rotating bodies 62 and 63; and belt skew regulation means 70 that regulates a range of belt skew. The belt skew regulation means includes an axis displacement part that displaces a position at one end of the axis of rotation of the support rotating body 63 by a movement of the belt in a belt width direction; an axis holding part 64 that tiltably holds the axis of rotation; and an axis displacement returning part 66 that is provided in the axis holding part and returns the position of one end of the axis of rotation displaced by the axis displacement part to the position before the displacement. The axis displacement returning part is located in a projection area of the belt device with vertical light when viewed from an axial direction of the support rotating bodies.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a belt device, a transfer device, and an image forming apparatus.

Conventionally, a belt stretched between a plurality of support rollers in a secondary transfer device or the like that primarily transfers a toner image of each color formed on a latent image carrier to an intermediate transfer member and then performs secondary transfer onto a recording material. There is known a belt device using a belt-like member. This type of belt device has a phenomenon in which the belt member approaches one end side in the belt width direction (belt side), or belt meandering in which the belt side toward each end in the belt width direction is repeated occurs. obtain.
As a belt device that keeps the range in which the belt member moves in the belt width direction due to this belt shift (belt shift range) within a certain regulation range, for example, Patent Document 1 describes the following belt device. Yes.

The belt device disclosed in Patent Document 1 includes an intermediate transfer belt that runs while being stretched around a plurality of support rotating bodies including a belt meandering correction roll, and a belt meander that keeps a range of the intermediate transfer belt close to the belt within a predetermined regulation range. And a correction mechanism (belt deviation regulating means).
The belt meandering correction mechanism includes a belt meandering correction member and a roll shaft support portion at an end of a rotation shaft (hereinafter simply referred to as “roll shaft”) of a belt meandering correction roll. The belt meandering correction member is an axial displacement portion that displaces the position of one end of the roll shaft by moving the intermediate transfer belt in the belt width direction, and has an inclined surface that approaches the center of the roll shaft as it goes outward in the roll axis direction. And installed so as to be movable along the roll axis. The roll shaft support portion is a shaft holding portion that supports the roll rotation shaft in a tiltable manner, and includes a tension spring having one end fixed to the frame of the belt device. The tension spring is an axial displacement return portion that returns the position of one end of the roll shaft displaced by the belt meandering correction member to the position before the displacement.

The belt meandering correction mechanism disclosed in Patent Document 1 can keep the belt shift within a certain range as follows. That is, when the end portion of the intermediate transfer belt approaches the one end side of the roll shaft, the belt meandering correction member that has received the pressing force due to the meandering of the intermediate transfer belt moves along the roll shaft, and the inclined surface of the belt meandering correction member Contact with part of belt device frame. Along with the movement of the belt meandering correction member, the contact position on the inclined surface of the belt meandering correction member is displaced, so that the position of the end portion of the roll shaft is displaced in a direction perpendicular to the roll axis and the roll axis is inclined. . With this inclination, it is possible to move the end of the intermediate transfer belt, which is close to one end of the belt meandering correction roll, in a direction to return the belt closer.
Further, the position of the roll shaft displaced by the belt meandering correction member can be corrected by the tension spring.

  However, other parts are often close to the periphery of the belt device such as the secondary transfer device, and a space for providing a member for regulating the belt deviation is limited. For this reason, when the belt meandering correction mechanism of Patent Document 1 is used in a belt device in which other components are close to each other, the following problems may occur. That is, there is a problem in that a member for regulating belt deviation, such as a tension spring, interferes with nearby components when correcting the belt deviation or correcting the roll axis position after the belt deviation correction.

In order to achieve the above-described problems, the present invention provides a belt member that travels while being stretched around a plurality of support rotating bodies, and a belt shift regulating means that regulates a range of the belt shift in which the belt member moves in the belt width direction. And the belt displacement restricting means displaces the position of at least one end of the rotation shaft of at least one of the plurality of support rotating bodies by moving the belt in the belt width direction. A shaft holding portion that holds the rotation shaft in a tiltable manner, and a shaft that is provided in the shaft holding portion and returns the position of one end of the rotation shaft displaced by the shaft displacement portion to a position before the displacement. In the belt device provided with the displacement return portion,
The axial displacement return portion is located in a projection region of the belt device by vertical light viewed from the axial direction of the support rotating body.

  According to the present invention, in the belt device provided with the belt deviation regulating means, the belt deviation regulating means hardly interferes with nearby components, and the belt deviation of the belt member can be controlled over time.

1 is a schematic configuration diagram illustrating an example of a printer according to an embodiment. FIG. 3 is a schematic diagram of the configuration of the shaft tilting mechanism immediately after assembly of the secondary transfer device provided in the printer when viewed from the axial direction of the separation roller. The schematic diagram when the structure of the coaxial tilting mechanism after deviation control is seen from the axial direction of the separation roller. 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. The schematic diagram which showed the structure of the coaxial tilting mechanism after belt deviation control with the cut surface cut | disconnected along the rotating shaft of the separation roller. FIG. 3 is an explanatory diagram of a belt shift in a secondary transfer belt. The perspective view of the shaft inclination member in a coaxial inclination mechanism. The schematic diagram when the positional relationship of a coaxial tilting mechanism and the nearby member is seen from the axial direction of the separation roller. FIG. 5 is a schematic diagram when another configuration of the secondary transfer device provided in the printer is viewed from the axial direction of the separation roller. FIG. 4 is a schematic diagram when the configuration in the vicinity of the cleaning blade included in the secondary transfer device illustrated in FIG. 2 is viewed from a direction perpendicular to the axial direction of the separation roller 64. The schematic diagram when the positional relationship of the conventional shaft inclination mechanism and the nearby member is seen from the axial direction of the separation roller.

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 an example of a printer according to the present embodiment.
The printer is provided with four photoconductors 1a, 1b, 1c and 1d which are latent image carriers 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, which is one of these support rollers, is rotationally driven by a driving source, and the intermediate transfer belt 51 travels in the direction of arrow A in the drawing by the rotational driving of the driving roller 53.

  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 photosensitive member 1a is initialized by irradiating the outer peripheral surface of the photosensitive member 1a with light from the static eliminator. 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 charged in this way is irradiated with a light-modulated laser beam L emitted from an exposure apparatus which is a latent image forming unit, whereby an electrostatic latent image is formed on the outer peripheral surface of the photosensitive member 1a. Is formed. 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 as developing means.

  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 single color mode, the primary transfer rollers 11b, 11c, and 11d are separated from the photoreceptors 1b, 1c, and 1d by the contact / separation mechanism, thereby causing the photoreceptors 1b, 1c, and 1d for magenta, cyan, and yellow to be separated. 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 a transfer sheet P as a sheet material, which is a transfer body, in the direction of 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 is stretched between a secondary transfer roller 62 and a separation roller 63. In the present embodiment, the secondary transfer roller 62 is driven to rotate as a drive roller, so that the secondary transfer belt 61 travels in a direction indicated by an arrow C in the drawing. 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 and a driven roller 17B as a driven rotating body. 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. For example, EPDM (ethylene-propylene-diene rubber) can be used as the material of the conveyance belt 17 of the present embodiment, and the belt thickness is, for example, 1 mm.

  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 intermediate transfer cleaning blade 21 formed of urethane or the like is used, and the intermediate transfer cleaning blade 21 is contacted from the counter direction with respect to the traveling direction of the intermediate transfer belt 51. Touching. 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 shaft tilting mechanism 70 that is a belt shift regulating means in the secondary transfer device 60 including the secondary transfer belt 61 will be described.
FIG. 2 is a schematic diagram of the configuration of the shaft tilt mechanism 70 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 view of the configuration of the shaft tilting mechanism 70 after the belt shift restriction is viewed from the axial direction of the separation roller 63.
The belt deviation restricting means of the secondary transfer device 60 in this embodiment is an axis inclination method, and the rotation axis of the separation roller 63, which is one of the support rollers that stretch the secondary transfer belt 61, is inclined. The shaft transfer mechanism 61 includes a shaft tilting mechanism 70 that restricts the belt shift range of the next transfer belt 61 within a predetermined restriction range.

In the separation roller 63 of this embodiment, both ends of the rotating shaft 63a are supported by rotating shaft support arms 64 that are separate shaft holding portions. 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 having one end fixed to the frame 68 of the secondary transfer device 60. The spring 66 is urged clockwise in FIG.
The arm spring 66 is a shaft displacement return portion that returns the position of one end portion of the separation roller 63 that has been displaced by a shaft tilting member 72 that is a shaft displacement portion described later to a position before the displacement. The installation position of the arm spring 66 in the secondary transfer device 60 will be described in detail later.
When the secondary transfer belt 61 is in the state immediately after the belt is not assembled, the rotation shaft support arm 64 is rotated at the position where the rotation shaft support arm 64 abuts the frame 68 by the urging force of the arm spring 66. Is held (FIG. 2).

  Further, as shown in FIGS. 2 and 3, each rotation shaft support arm 64 is capable of sliding a bearing portion 65 that receives the rotation shaft 63 a of the separation roller 63 in the radial direction from the rotation center of the rotation shaft support arm 64. I support it. The 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 applies a predetermined tension to the secondary transfer belt 61 stretched between the separation roller 63 and the secondary transfer roller 62. can do.

FIG. 4 is a schematic view showing the configuration of the coaxial 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.
FIG. 5 is a schematic diagram showing a configuration of the coaxial tilt mechanism 70 after the belt shift restriction is shown by a cut surface cut along the rotation axis of the separation roller.
As shown in FIG. 4, the separation roller 63 is provided with a belt shift detection member 71 and a shaft inclination member 72 constituting an axial displacement member on a rotation shaft 63 a between the separation roller 63 and the bearing portion 65. ing. 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 inclination 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 provided on the frame 68 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 biased by the arm spring 66 via the 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 contact position between the inclined surface 72a of the shaft inclined member 72 and the contact portion 68a of the frame 68 is restricted at a position where the stopper surface 68b of the frame 68 contacts the stopper surface 72b. 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.

  From this state, when the secondary transfer belt 61 receives a force of moving in the belt width direction, and the belt shift detecting member 71 and the shaft tilting member 72 move outward in the axial direction along the rotation shaft 63a, the shaft tilting member 72 The contact 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, the end of the rotating 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. Therefore, as shown in FIG. 4, the contact portion 68 a of the frame 68 is held in a state of being in contact with the lower end portion of the inclined surface 72 a of the shaft inclined member 72. Therefore, the end of the rotation shaft 63a of the separation roller 63 on the opposite side to the direction in which the secondary transfer belt 61 moves is pressed down relative to the other end side, and the rotation shaft 63a is inclined. It will be.

  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. This is the same even when the belt of the secondary transfer belt 61 is generated in the reverse direction.

Here, the principle that 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.
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, the separation roller 63 is displaced in the direction of the rotation axis by approximately tanα as shown in FIG. 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. Therefore, for example, as shown in FIG. 5, when the secondary transfer belt 61 is shifted toward the right side in FIG. 5, the shaft inclined member 72 moves in the direction of the separation roller rotation axis due to this belt shift. As a result, the rotation shaft 63a of the separation roller 63 is lowered to the lower side in the drawing, so that it is possible to cause a belt shift to return the secondary transfer belt 61 to the left side in FIG. 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 tilt member 72 in the coaxial tilt mechanism 70.
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.

When the rotation axis of the separation roller 63 is not inclined and the belt deviation range is not restricted, the end surface of the secondary transfer belt 61 is directly pressed by the belt deviation detection member 71 provided at the end of the separation roller 63. Always stressed. The end surface of the belt member is the weakest part of the belt, and if the secondary transfer belt 61 is run while the end surface of the secondary transfer belt 61 is always stressed, the end portion of the secondary transfer belt 61 sometimes breaks. Was observed.
According to the belt deviation regulating means of this embodiment, the load on the end face of the secondary transfer belt 61 can be reduced and the belt deviation can be controlled by inclining the separation roller 63.

  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. Therefore, a reinforcing tape may be attached to the end of 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
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 arm spring 66 that is the shaft inclination returning member will be described in detail. Generally, a large number of parts are close to each other around the secondary transfer device, and the space for arranging the belt deviation regulating means is narrowed. Yes. For this reason, the secondary transfer apparatus having the belt deviation regulating means has the following problems depending on the arrangement of the axial displacement return portion such as a tension spring provided in the belt deviation regulating means. That is, when correcting the belt shift or correcting the roller shaft position after the belt shift correction, the tension spring comes into contact with the surrounding parts, and the belt shift cannot be converged.

FIG. 11 is a schematic diagram of the positional relationship between the conventional shaft tilt mechanism 270 and nearby members when viewed from the axial direction of the separation roller.
The secondary transfer device 260 shown in FIG. 11 has the same configuration as the secondary transfer device 60 described with reference to FIG. 2 except that the arrangement of the arm springs 266 provided in the shaft tilt mechanism 270 is different. For this reason, parts similar to those of the secondary transfer device 60 of FIG.

For example, as shown in FIG. 11, when components such as the conveyance belt 17, the intermediate transfer belt 51, and the belt cleaning device 20 are present in the vicinity of the secondary transfer device 260, the following problems occur. . In other words, the arm spring 266 comes into contact with the peripheral components of the secondary transfer device 260 when correcting the belt deviation or correcting the roller shaft position after the belt deviation correction, and the belt deviation cannot be converged. End up.
Therefore, in the secondary transfer device 60 of this embodiment, the position of the arm spring 66 with respect to the secondary transfer device 60 is set as follows.

FIG. 8 is a schematic view of the positional relationship between the shaft tilting mechanism shown in FIG. 2 and nearby members when viewed from the axial direction of the separation roller 63.
Around the secondary transfer device 60 of the present embodiment, the conveyance belt 17 is disposed on the downstream side of the secondary transfer device 60 in the conveyance direction of the transfer paper, and the intermediate transfer belt 51 and the belt cleaning are disposed above the secondary transfer device 60. A device 20 is arranged.
Also, below the secondary transfer device 60, from the viewpoint of paper jam processing between the intermediate transfer belt 51 and the secondary transfer belt 61, secondary transfer about the contact / separation shaft 90 with respect to the intermediate transfer belt 51 is performed. A contact / separation mechanism for separating the secondary transfer belt 61 from the intermediate transfer belt 51 by rotating the device 60 is disposed.
Further, around the shaft tilting mechanism 70, a secondary transfer cleaning blade 81 for removing transfer residual toner adhering to the outer peripheral surface of the secondary transfer belt 61 after secondary transfer of the toner image onto the transfer, and waste And a toner transport mechanism. This waste toner transport mechanism includes a waste toner coil 82 that is transmitted from a drive source 83 through a plurality of gears 84, and the toner collected by the secondary transfer cleaning blade 81 is sent by the waste toner coil 82. It is transported to the waste toner transport path.

In the secondary transfer device 60 of the present embodiment, the entire arm spring 66 is within the projection area (hereinafter simply referred to as “projection area”) of the secondary transfer apparatus 60 by vertical light viewed from the axial direction of the secondary transfer roller 62. Arranged to position. Note that the projection area in the present embodiment is the projection area of the shaft tilting mechanism 70 and the frame 68 excluding the arm spring 66 by vertical light viewed from the axial direction of the secondary transfer roller 62.
As a result, the main movable range of the arm spring at the time of correcting the belt shift or correcting the roller shaft position after the belt shift correction is inside the projection area of the secondary transfer device 60. Therefore, even when other components are close to the secondary transfer device 60 and a space for providing a member for regulating the belt deviation is limited, the arm spring 66 and the adjacent components do not interfere with each other, and the belt over time. The belt deviation of the member can be controlled.

Further, in the secondary transfer device 60 of the present embodiment, the arm spring 66 is disposed inside the projection area of the secondary transfer device 60 when viewed from the axial direction of the secondary transfer roller 62, thereby performing the secondary transfer. The device 60 can be miniaturized.
Specifically, in the secondary transfer device 60 of the present embodiment, the upstream side of the rotation axis of the secondary transfer roller 62 located on the most upstream side in the paper conveyance direction among the support rollers of the secondary transfer device 60 is upstream of the paper conveyance direction. An arm spring 66 is disposed on the side.
In the secondary transfer device, there is a relatively large space on the upstream side in the sheet passing direction. For this reason, in the secondary transfer device 60 of the present embodiment, a wide space for disposing the belt deviation restricting means to prevent interference between the parts near the secondary transfer device and the arm spring 66 is ensured. The arm spring 66 and nearby components can suppress interference. Therefore, it is possible to reduce the size of the belt device having the belt deviation regulating means.

FIG. 9 is a schematic diagram when another configuration of the secondary transfer device provided in the printer is viewed from the axial direction of the separation roller 63.
The secondary transfer device 160 shown in FIG. 9 has the same configuration as the secondary transfer device 60 described with reference to FIG. 2 except that the secondary transfer device 60 is provided with a lubricant application brush roller 85. For this reason, parts similar to those of the secondary transfer device 60 of FIG.
In a general secondary transfer apparatus, a lubricant may be applied to the belt in order to prevent filming on the belt or to prevent blade entrainment. For this reason, as shown in FIG. 9, the lubricant application brush roller 85 may be brought into contact with the secondary transfer belt 61 in order to apply the lubricant to the belt.

However, when the lubricant application brush roller 85 is provided in the secondary transfer device, the lubricant application brush roller 85 is rotated when the lubricant is applied to the secondary transfer belt 61, and therefore the gear 86 is provided in the secondary transfer device. Need to be placed. For this reason, the space for disposing the arm spring 66 is limited, and the space for disposing the belt deviation restricting means must be widened so that the arm spring 66 does not interfere with the gear 86 of the lubricant application brush roller 85. The secondary transfer device becomes large.
For this reason, in the secondary transfer device 60 of the present embodiment, as shown in FIG. 8, the lubricant application member is not mounted. That is, in the secondary transfer device 60 of the present embodiment, the member that comes into contact with the portion of the outer peripheral surface of the secondary transfer belt 61 that is wound around the secondary transfer roller 62 is the secondary transfer cleaning blade 81, and toner leakage described later. Only the toner leakage prevention seal member 87 and the intermediate transfer belt 51 which are prevention means are provided.
Thereby, it is possible to secure a space for arranging the components of the belt deviation regulating means, and it is possible to suppress an increase in the size of the secondary transfer device.

FIG. 10 is a schematic view of the configuration in the vicinity of the secondary transfer cleaning blade 81 included in the secondary transfer device 60 shown in FIG. 8 when viewed from the direction perpendicular to the axial direction of the separation roller 64.
In the axial direction of the secondary transfer roller 62, toner leakage prevention seal members 87 are disposed at both ends of the secondary transfer cleaning blade 81, respectively. The toner leakage prevention seal member 87 is for preventing the toner cleaned by the secondary transfer cleaning blade 150 from scattering around.

In this embodiment, the material of the secondary transfer cleaning blade 81 is urethane rubber, and a material having a rubber hardness (Shore A) of 90 in contact with the secondary transfer belt 61 is used. The hardness of the cleaning blade 81 is not limited to this.
The rubber hardness of the secondary transfer cleaning blade 81 is preferably higher because the blade is less likely to be caught in the secondary transfer belt. However, if the rubber hardness is too high, the secondary transfer cleaning blade 81 cannot follow the minute irregularities of the secondary transfer belt, so that a cleaning failure occurs or the secondary transfer cleaning blade 81 tends to be chipped. Therefore, it is preferable to set the rubber hardness suitable for the system each time.

What was demonstrated above is an example, and there exists an effect peculiar for every following aspect.
(Aspect A)
The belt member such as the secondary transfer belt 61 that travels while being stretched around a plurality of supporting rotating bodies such as the secondary transfer roller 62 and the separation roller 63, and the belt-closed range in which the belt member moves in the belt width direction are regulated. A belt deviation regulating means such as a shaft tilting mechanism 70, and the belt deviation regulating means is a position of at least one end portion of a rotating shaft of a supporting rotating body such as at least one separation roller 63 among the plurality of supporting rotating bodies. A shaft displacement portion such as a shaft tilting member 72 that displaces the belt by movement in the belt width direction, a shaft holding portion such as a rotation shaft support arm 64 that tiltably holds the rotation shaft, and a shaft holding portion. A secondary transfer device 60 or the like provided with an axial displacement return portion such as an arm spring 66 that is provided and returns the position of one end of the rotating shaft displaced by the shaft displacement portion to the position before the displacement. In winding device, wherein the axis displacement return portion, characterized in that located in the projection area of the belt device according to a vertical light as viewed from the axial direction of the supporting rotator.

  In this aspect, as described in the above embodiment, at least a part of the movable range of the arm spring when correcting the belt shift or correcting the roller shaft position after the belt shift correction is projected by the secondary transfer device. Inside the area. Therefore, even when other parts are close to the secondary transfer apparatus and a space for providing a member for regulating the belt deviation is limited, the arm spring 66 and the nearby parts are unlikely to interfere with each other, and the belt member is kept over time. It is possible to control the belt deviation.

(Aspect B)
In the aspect A, the shaft includes a shaft holding member such as a frame 68 that indirectly or directly holds the rotation shafts of the plurality of supporting rotating bodies such as the secondary transfer roller 62 and the separation roller 63, and the shaft such as the arm spring 66. A displacement return part is located in the projection area | region of the belt deviation | shift control means except the said shaft displacement return part by the perpendicular light seen from the axial direction of the said support rotary body, and the said shaft holding member.
As a result, the main movable range of the arm spring when correcting the belt deviation or correcting the roller shaft position after the belt deviation correction is inside the projection area of the secondary transfer device. Therefore, even when other parts are close to the secondary transfer apparatus and a space for providing a member for regulating the belt deviation is limited, the arm spring 66 and the adjacent parts do not interfere with each other, and the belt member over time. It is possible to control the belt deviation.

(Aspect C)
A belt device including a belt member such as a secondary transfer belt 61 that travels while being stretched around a plurality of support rotating bodies such as a secondary transfer roller 62 and a separation roller 63, and is carried on the outer peripheral surface of the belt member In the transfer device such as the secondary transfer device 60 that transfers the toner image formed on the image carrier such as the intermediate transfer belt 51 onto the transfer member such as the transfer paper P that is being conveyed, Using the belt device of aspect B, a supporting rotating body such as a separation roller 63 whose position of the rotating shaft can be displaced by the shaft displacement portion such as the shaft tilting member 72 is the outermost of the plurality of supporting rotating bodies. The shaft inclined return portion such as the arm spring 66 is located downstream, and the transport is more than the rotation shaft of the support rotator such as the secondary transfer roller 62 positioned at the most upstream in the transport direction among the plurality of support rotators. Direction Characterized in that located on the side.

  Generally, the transfer device has a relatively large space on the upstream side in the sheet passing direction. For this reason, in this aspect, the arm spring 66 and the vicinity thereof are not secured without securing a wide space for disposing the belt deviation regulating means in order to prevent interference between the parts near the secondary transfer device and the arm spring 66. The component can suppress interference. Therefore, it is possible to reduce the size of the belt device having the belt deviation regulating means.

(Aspect D)
In aspect C, a portion of the outer peripheral surface of the belt member such as the secondary transfer belt 61 that is wound around a support rotating body such as the secondary transfer roller 62 that is positioned at the most upstream in the transport direction is on the surface of the belt member. Only the cleaning blade such as the secondary transfer cleaning blade 81 for removing the toner, the image carrier such as the intermediate transfer belt 51, and the toner leakage prevention means such as the toner leakage prevention seal member 87 are in contact with each other. .

When the lubricant transfer brush roller 85 is provided in the secondary transfer device 60, the gear 86 is disposed in the secondary transfer device to rotate the lubricant application brush roller 85 when applying the lubricant to the secondary transfer belt 61. There is a need to. For this reason, the space for disposing the arm spring 66 is limited, and the space for disposing the belt deviation restricting means must be widened so that the arm spring 66 does not interfere with the gear 86 of the lubricant application brush roller 85. The secondary transfer device becomes large.
In this aspect, it is possible to secure a space for arranging the components of the belt deviation regulating means, and it is possible to suppress an increase in the size of the secondary transfer device.

(Aspect E)
Development processing such as a latent image carrier such as the photoreceptor 1a, a latent image forming unit that forms a latent image on the latent image carrier, and a developing device 10a that attaches toner to the latent image on the latent image carrier And a recording material conveying means for conveying the recording material, and the toner image formed on the latent image carrier by the development processing is finally transferred to the recording material, thereby recording material In the image forming apparatus for forming an image thereon, the belt device according to aspect A or aspect B is used as the recording material conveying unit.

(Aspect F)
A latent image carrier such as the photosensitive member 1a, a latent image forming unit that forms a latent image on the latent image carrier, and a developing device 10a that performs development processing for attaching toner to the latent image on the latent image carrier. Developing means, an intermediate transfer member such as an intermediate transfer belt 51 that transfers and carries a toner image formed on the latent image carrier, and a transfer member such as transfer paper P that transfers the toner image on the intermediate transfer member. In an image forming apparatus provided with a transfer unit such as a secondary transfer unit 60 that transfers the image on the upper side, the transfer unit of mode C or mode D is used as the transfer unit.

DESCRIPTION OF SYMBOLS 1 Photoconductor 8 Charging device 10 Developing device 11 Primary transfer roller 14 Paper feeding device 17 Conveying belt 18 Fixing device 20 Belt cleaning device 21 Intermediate transfer cleaning blade 51 Intermediate transfer belt 60 Secondary transfer device 61 Secondary transfer belt 62 Secondary transfer Roller 63 Separation roller 64 Rotating shaft support arm 66 Arm spring 70 Shaft tilting mechanism 72 Shaft tilting member 81 Secondary transfer cleaning blade 82 Waste toner coil 85 Lubricant application brush roller 87 Toner leakage prevention seal member P Transfer paper

JP 2010-230958 A

Claims (6)

  A belt member that is stretched around a plurality of support rotating bodies, and belt deviation regulating means that regulates a belt deviation range in which the belt member moves in the belt width direction. A shaft displacement portion for displacing the position of at least one end of the rotation shaft of at least one of the support rotation bodies by movement of the belt in the belt width direction, and shaft holding for holding the rotation shaft in a tiltable manner And a shaft displacement return unit that is provided in the shaft holding unit and returns a position of one end of the rotary shaft that has been displaced by the shaft displacement unit to a position before the displacement. The belt device, wherein the displacement return portion is located in a projection region of the belt device by vertical light viewed from the axial direction of the support rotating body.   2. The belt device according to claim 1, further comprising: a shaft holding member that indirectly or directly holds the rotation shafts of the plurality of supporting rotating bodies, wherein the shaft displacement return portion is perpendicular to the axial direction of the supporting rotating body. A belt device, wherein the belt device is located within a projection region of the belt holding regulating means and the shaft holding member excluding the shaft displacement return portion by light.   A toner image formed on an image carrier on a transfer member having a belt device including a belt member that is stretched around a plurality of support rotating members and carried on the outer peripheral surface of the belt member In the transfer device for transferring the image, the belt device according to claim 1 or 2 is used as the belt device, and a support rotating body whose position of a rotation shaft is displaced by the shaft displacement portion is a transfer body among the plurality of support rotating bodies. The shaft tilt return portion is located on the most downstream side in the transport direction, and the shaft inclined return portion is located on the upstream side in the transport direction with respect to the rotation axis of the support rotator located on the most upstream side in the transport direction among the plurality of support rotators. The transfer device.   4. The transfer device according to claim 3, wherein a portion of the outer peripheral surface of the belt member that is wound around a support rotating body that is positioned at the most upstream in the transport direction is a cleaning blade that removes toner on the surface of the belt member, and the image. A transfer device, wherein only the carrier and the toner leakage prevention means are in contact with each other.   A latent image bearing member; a latent image forming unit that forms a latent image on the latent image bearing member; a developing unit that performs a developing process for attaching toner to the latent image on the latent image bearing member; And an image forming apparatus for forming an image on the recording material by finally transferring the toner image formed on the latent image carrier by the development processing to the recording material. An image forming apparatus using the belt device according to claim 1 or 2 as the recording material conveying means.   A latent image carrier, a latent image forming unit that forms a latent image on the latent image carrier, a developing unit that performs a developing process for attaching toner to the latent image on the latent image carrier, and a latent image carrier An image forming apparatus comprising: an intermediate transfer member that transfers and carries a toner image formed thereon; and a transfer unit that transfers the toner image on the intermediate transfer member onto the transfer member. An image forming apparatus using 3 or 4 transfer device.

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