JP2016156874A - Belt control apparatus and image forming apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a belt control apparatus for reducing a load applied to a belt end by preventing the increase of a contact area between a rotation support member for supporting a rotation shaft and the side plate of an apparatus housing, even when a roller is inclined.SOLUTION: A belt control apparatus 6 includes: a belt member 60; a plurality of rotary bodies 61 on which the belt member 60 is wound; a rocking support member 134 which rockably supports one of the plurality of rotary bodies as a movable rotary body 61; an immovable fixed side plate 150; a skew detection member 130 which is arranged at the end of the movable rotary body 61 and detects the movement of the belt member 60 in a rotation axis direction Y of the movable rotary body 61; an inclination member 131 which is arranged between the skew detection member 130 and the rocking support member 134 and inclines a rotation shaft 61a of the movable rotary body 61 by the movement of the belt member 60 in the rotation axis direction Y; and a plurality of projection parts 132 which are formed between the fixed side plate 150 and the rocking support member 134. The plurality of projection parts 132 come into point contact with one of the fixed side plate 150 and the rocking support member 134.SELECTED DRAWING: Figure 3

Description

  The present invention relates to a belt control device that controls movement of a belt, which is stretched around a plurality of rollers and travels along with the rotation of the rollers, in the axial direction of the roller, and an image forming apparatus having the belt control device.

In conventional image forming apparatuses, various belts are used as an intermediate transfer member, a recording medium conveyance unit, an image fixing unit, or the like. These belts are stretched over at least two rollers provided in parallel to each other, and are configured to run as the rollers rotate.
However, a plurality of rollers may not be parallel to each other due to deterioration of parts used for rotating the rollers, assembly accuracy, or the like.

  If the plurality of rollers are not parallel to each other, a so-called belt shift or belt meandering may occur in which the belt moves in the axial direction of the roller (hereinafter referred to as the rotational axis direction).

Various belt position control means have been proposed in order to keep the movement range in the rotation axis direction of the belt moved in the rotation axis direction within a certain regulation range (see Patent Documents 1 to 6).
For example, a structure in which guide ribs are provided at both ends of the belt inner circumferential surface in the belt width direction (see Patent Document 1), and a direction in which the rotation shaft of the roller that stretches the belt is tilted by a swing support member to return the belt side. There is known a structure for moving a belt (see Patent Documents 2, 3, etc.).
As one structure for tilting the rotation axis of the roller using such a swing support member, for example, the swing support member is supported by a fixed side plate such as a side plate of an apparatus housing, and the swing support member is fixed by the belt. A structure in which the rotation axis is inclined by inclining with respect to the side plate is conceivable.

  However, in the structure in which the swing support member is tilted and the rotation axis of the roller is tilted, the contact area between the swing support member and the fixed side plate is increased when the roller is tilted. There was a risk that the load on the part would increase.

  In order to solve the above-described problem, in the belt control device of the present invention, an endless belt member, a plurality of rotating bodies wound around the belt member, and one of the plurality of rotating bodies is a movable rotating body. As a swing support member that is supported so as to be swingable, an immovable fixed side plate, and an end of the movable rotating body, and detecting the shift of the belt member in the rotational axis direction of the movable rotating body An inclination member disposed between the member, the shift detection member, and the swing support member, for inclining the rotation axis of the movable rotating body by the movement of the belt member in the rotation axis direction, and the fixing A plurality of protrusions formed between the side plate and the swing support member, and each of the plurality of protrusions is in point contact with one of the fixed side plate and the swing support member. It is characterized by doing.

  According to the present invention, the load applied to the belt end portion is reduced by not increasing the contact area between the swing support member that supports the rotating shaft of the roller and the fixed side plate even when the roller is inclined.

1 is a schematic configuration diagram illustrating an example of an image forming apparatus according to an exemplary embodiment. It is the schematic which shows an example of the belt control apparatus concerning this embodiment. It is a figure showing an example of the inclination member concerning this embodiment, and a separation roller. It is a perspective view showing an example of the inclination member concerning this embodiment. It is a figure which shows an example of the operation | movement in the inclination state of the inclination member shown in FIG. It is a figure showing an example of the operation | movement in the inclination state of the belt control apparatus shown in FIG. It is a conceptual diagram showing the inclination state of the belt control apparatus concerning this embodiment. It is a figure which shows an example of the result of the durability evaluation test of the belt control apparatus concerning this embodiment. It is a figure which shows another example of the positional relationship of the projection part concerning this embodiment. It is the schematic showing an example of the positional relationship of the inclination member concerning this embodiment, and a stationary side plate.

As an example of an embodiment of the present invention, an image forming apparatus 100 configured as a printer illustrated in FIG. 1 will be described.
The image forming apparatus 100 includes a transfer belt 3 that is an intermediate transfer member for transferring an image onto a sheet P that is a recording medium, a sheet feeding device 1 that supplies the sheet P toward the transfer belt 3, and recording on the transfer belt 3. And an image forming unit 4 for forming an image using the toner as the agent.
The image forming apparatus 100 transfers an image at a secondary transfer position N2 that is a nip portion between the optical scanning device 5 serving as an optical writing unit serving as an exposure unit that emits light toward the image forming unit 4 and the transfer belt 3. And transfer transfer means 6 as secondary transfer means for transferring from 3 to paper P.
The image forming apparatus 100 remains on the transfer belt 3 after the image transferred at the secondary transfer position N2 is fixed on the paper P by heat and pressure, and after the image is transferred at the secondary transfer position N2. A belt cleaning device 8 for removing toner.
The image forming apparatus 100 includes a registration roller pair 12 that feeds the paper P toward the secondary transfer position N2.

The image forming unit 4 includes four process cartridges 4C, 4M, 4Y, and 4K corresponding to the four basic colors of cyan C, magenta M, yellow Y, and black K, respectively.
Here, in order to simplify the description, only the process cartridge 4K among the process cartridges 4C, 4M, 4Y, and 4K will be described, but the other process cartridges 4C, 4M, and 4Y have the same configuration. .

The process cartridge 4K includes a photosensitive member 40 as a rotating member that rotates in the A direction, which is an image carrier that carries a toner image, a charging unit 41 that uniformly charges the photosensitive member 40 to a negative polarity, and a static eliminating member. That is, a charge eliminating unit that initializes the potential of the surface of the photoreceptor 40.
The process cartridge 4K has a developing unit 42 that develops the electrostatic latent image written on the photoconductor 40 by the optical scanning device 5 as a toner image, and a primary transfer position N where the transfer belt 3 and the photoconductor 40 abut. And a cleaning device 43 formed downstream in the A direction.

  The optical scanning device 5 is disposed above the image forming unit 4 and irradiates the photosensitive member 40 with laser light, thereby forming an electrostatic latent image on the surface of the photosensitive member 40 according to writing information as image information. To do.

  The surface of the photoconductor 40 is initialized by the charge eliminating unit, and then uniformly charged to the negative polarity by the charging unit 41. The surface of the uniformly charged photoreceptor 40 is irradiated with laser light from the optical scanning device 5 to form an electrostatic latent image.

The developing unit 42 develops the electrostatic latent image by attaching toner to the electrostatic latent image formed on the photoconductor 40, and visualizes it as a black toner image.
A primary transfer roller 421 is provided downstream of the developing unit 42 in the A direction so as to face the photoconductor 40 at the primary transfer position N and sandwich the transfer belt 3. The primary transfer roller 421 applies a positive polarity transfer voltage that is opposite in polarity to the toner charge polarity of the toner image formed on the photoreceptor 40. As a result, a transfer electric field is formed between the photoreceptor 40 and the transfer belt 3, and the toner image on the photoreceptor 40 is electrostatically transferred onto the transfer belt 3 that is rotationally driven in synchronization with the photoreceptor 40. The
The cleaning device 43 is toner removing means provided downstream in the A direction from the primary transfer position N and upstream in the A direction from the neutralization unit, and the surface of the photoreceptor 40 after the toner image is transferred to the transfer belt 3. The transfer residual toner adhering to the toner is removed, and the surface of the photoreceptor 40 is cleaned.

The transfer belt 3 is an endless belt wound around a drive roller 31, a tension roller 32, a support roller 34 and a repulsive roller 35.
Any one of the driving roller 31, the tension roller 32, the support roller 34, and the repulsive roller 35 is referred to as a roller without being particularly distinguished. These rollers have an aluminum cylindrical core and a silicone rubber layer formed on the outer periphery of the cylinder.

  The transfer belt 3 moves in the direction indicated by the arrow B when the drive roller 31 is rotationally driven by a drive source. The transfer belt 3 may have a multilayer structure or a single layer structure, but in this embodiment, has a multilayer structure having a surface layer and a base layer. In the case of a multilayer structure, the base layer is made of, for example, a fluororesin, PVDF sheet, or polyimide resin that has little elongation, and the surface layer that is in contact with the paper P at the secondary transfer position N2 has a smooth surface such as a fluororesin as a surface layer. It is preferable to provide a good coat layer. In the case of a single layer, it is preferable to use a material such as PVDF, PC, or polyimide.

  The paper feeding device 1 includes a paper feeding roller 11 that conveys the paper P stored and held on the tray toward the registration roller pair 12.

  The registration roller pair 12 temporarily stops the paper P supplied from the paper feeding device 1 and transfers the paper P to the secondary transfer position so that the toner image formed on the transfer belt 3 is transferred to the paper P. Adjust the transfer timing to N2.

The transfer conveying means 6 separates the secondary transfer belt 60 that is an endless belt member, the secondary transfer roller 62 around which the secondary transfer belt 60 is wound, and the paper P and the secondary transfer belt 60. And a separation roller 61.
The transfer conveying means 6 has a function as a belt control device for correcting the secondary transfer belt 60 so as to return the shift.
The secondary transfer belt 60 is a belt member wound around the secondary transfer roller 62 and the separation roller 61, in other words, a stretched belt member.
Other configurations such as the material of the secondary transfer belt 60 are the same as those of the transfer belt 3, and the description thereof is omitted.

  The secondary transfer roller 62 is a driving unit that is disposed to face the repulsive roller 35 and drives the secondary transfer belt 60 to rotate in the C direction. The secondary transfer position N2 is formed by rotating with the secondary transfer belt 60 interposed therebetween.

The separation roller 61 is a roller that is a cylindrical rotating body around which the secondary transfer belt 60 is wound together with the secondary transfer roller 62, and rotates with the secondary transfer belt 60 according to the rotation of the secondary transfer roller 62.
The sheet P on which the toner image is transferred at the secondary transfer position N2 by the rotation of the secondary transfer roller 62 is transferred toward the fixing unit 7.

The fixing unit 7 is a fixing unit that fixes the toner image on the paper P by the action of heat and pressure.
The fixing unit 7 is disposed opposite to the heating roller 71 having a heat source such as a heater in order to heat the paper P, and is in contact with the heating roller 71 to form a fixing nip portion. And a pressure roller 72.
The heating roller 71 includes an aluminum cylindrical roller, a silicone rubber layer formed on the outer periphery of the cylinder, and a halogen heater as a heat generator disposed inside the cylinder.
The configuration of the pressure roller 72 is the same as that of the other rollers such as the drive roller 31, the tension roller 32, the support roller 34, and the repulsive roller 35, and thus the description thereof is omitted.

The belt cleaning device 8 removes the transfer residual toner attached on the transfer belt 3 after the toner image is transferred. The belt cleaning device 8 has a blade-shaped cleaning blade 21 made of urethane or the like, and the cleaning blade 21 is provided so as to scrape off transfer residual toner attached to the transfer belt 3.
Various types of belt cleaning devices 8 can be used as appropriate. For example, instead of the cleaning blade 21, an electrostatic cleaning method using a conductive fur brush may be used.

A method for forming an image using the image forming apparatus 100 having the above-described configuration will be described.
When image information is given from a terminal connected to the outside of the image forming apparatus 100, the optical scanning device 5 converts each color of the basic colors cyan C, magenta M, yellow Y, and black K based on the image information. An electrostatic latent image is formed on each corresponding photoreceptor 40.
The electrostatic latent image formed on the photoreceptor 40 is visualized as a toner image by attaching a corresponding basic color toner by the developing unit 42, and then the primary latent image at the primary transfer position N. The image is transferred onto the transfer belt 3 by a transfer voltage applied to the transfer roller 421.
The transfer residual toner remaining on the photoreceptor 40 after the toner image is transferred is removed by the cleaning device 43, and the surface of the photoreceptor 40 is cleaned to prepare for the next image formation.

  With this operation, the toner image corresponding to each color of cyan C, magenta M, yellow Y, and black K is transferred onto the transfer belt 3.

At this time, the image forming unit 4 operates in accordance with a mode selected from two types of modes, a full color mode using four basic colors and a black single color mode using only black K.
In the full color mode, the transfer belt 3 and the photoreceptors 40 corresponding to the respective basic colors are all in contact with each other, and toner images of all four basic colors are formed.
On the other hand, in the black monochrome mode, only the photoconductor 40 corresponding to black K is brought into contact with the transfer belt 3, and only the toner image using black toner is transferred to the transfer belt 3.

In synchronization with the image forming process, the paper P stored in the paper feed tray is conveyed to the registration roller pair 12 by the rotation of the paper feed roller 11.
The registration roller pair 12 adjusts an appropriate timing so that the toner image formed on the transfer belt 3 is transferred to a predetermined position on the paper P, and conveys the paper P to the secondary transfer position N2. .

A predetermined transfer voltage is applied to the repulsive force roller 35 at the secondary transfer position N2.
With this transfer voltage, the toner image formed on the transfer belt 3 is transferred to the paper P transported between the secondary transfer belt 60 and the transfer belt 3 and transported in the C direction.

When the sheet P is separated from the secondary transfer belt 60 by the separation roller 61, the sheet P is transported to the fixing unit 7 along the transport path.
In the fixing unit 7, the paper P is heated and pressed by the heating roller 71 and the pressure roller 72 in the fixing nip portion. The toner image held on the surface of the paper P is fixed as an image by the pressurizing / heating process.

  The sheet P on which the image is fixed is discharged to the outside of the image forming apparatus 100 by a discharge roller. Note that the image forming apparatus 100 may have a conveyance path for duplex printing in which the fixed sheet P is reversed and conveyed to the registration roller pair 12.

In a configuration in which a belt member, for example, the secondary transfer belt 60 is used for transporting the paper P as in the image forming apparatus 100, the following phenomenon may occur. That is, when the belt member rotates, the belt member may move in the width direction of the belt member, in other words, in the direction of the rotation axis of the roller that stretches the belt member, for example, the separation roller 61, in other words, the belt may be displaced. .
Although a method of restricting the belt side by pressing with a guide or the like is conceivable, if a force acts in the direction of pressing the weakest end surface of the belt member, the load on the belt member is large.

In order to suppress the belt shift, the transfer conveyance unit 6 of the present embodiment functions as a belt control device having a belt control unit as described below.
Here, only the transfer / conveying means 6 will be described. However, unless otherwise specified, the transfer / conveying means 6 may be replaced with any of the configurations including the belt member in the image forming apparatus 100 already mentioned, such as the transfer belt 3. Also good.

FIG. 2 is a schematic cross-sectional view of the transfer / conveying means 6 as seen from the axial direction of the separation roller shaft 61a which is a movable rotation shaft of the separation roller 61.
Here, the axial direction of the secondary transfer roller 62, that is, the direction perpendicular to the paper surface in FIG. 2 is defined as the Y direction, and the directions perpendicular to the Y direction are respectively perpendicular to the X direction and Z direction as shown in FIG. It is determined.
Since the secondary transfer roller 62 and the separation roller 61 are arranged in parallel in an initial state to be described later, the separation roller shaft 61a and the Y axis are parallel in the initial state.
FIG. 3 is a view of the transfer transport unit 6 as viewed from the −Z direction shown in FIG. 2, that is, from the left side of FIG.

As shown in FIG. 2, the transfer conveying means 6 is a swing support member that swingably supports the separation roller 61 as a movable rotating body among the secondary transfer roller 62 and the separation roller 61 that are a plurality of rotating bodies. A rotation support member 134 is provided. The transfer conveyance unit 6 includes a fixed stationary side plate 150 that is integrally formed with the housing of the image forming apparatus 100 on the secondary transfer belt 60 side of the rotation support member 134.
As shown in FIG. 3, the transfer conveying unit 6 is disposed at the end of the separation roller 61 so as to surround the periphery of the separation roller shaft 61 a, and is a secondary transfer belt in the Y direction that is the rotation axis direction of the separation roller 61. A deviation detecting member 130 as a belt deviation detecting member for detecting the movement of 60 is provided.
The transfer conveyance unit 6 is disposed between the shift detection member 130 and the rotation support member 134, and has an inclined member 131 for inclining the separation roller shaft 61a by the movement of the secondary transfer belt 60 in the Y direction. ing.
The transfer / conveying means 6 has a plurality of protrusions 132 that are a plurality of point contact portions formed between the fixed side plate 150 and the rotation support member 134.

  As shown in FIGS. 3 and 4, the inclined member 131 has a cylindrical main body 131b and a protrusion 131c having an inclined surface 131a inclined by an angle β on the outer peripheral surface 131d of the main body 131b. .

The fixed side plate 150 is a side plate that does not move with respect to the housing of the image forming apparatus 100, and includes a contact portion 150a that contacts the inclined surface 131a and a stopper surface 150b that contacts the outer peripheral surface 131d and functions as a stopper. Have.
The fixed side plate 150 is penetrated by the rotation support member 134 and the rotation shaft of the secondary transfer roller 62 and the separation roller shaft 61a. The fixed side plate 150 rotatably supports the rotation shaft of the secondary transfer roller 62 together with the rotation support member 134.
The fixed side plate 150 is inserted with a predetermined play with respect to the separation roller shaft 61a.

The rotation support member 134 is in contact with the plate-like roller support portion 135 that rotatably supports the separation roller shaft 61a and the side surface of the roller support portion 135, and slides the roller support portion 135 in the X direction or the Z direction. And a groove portion 136 that is movably supported in a manner.
One side of the rotation support member 134 is rotatably connected to the rotation shaft of the secondary transfer roller 62, and the other side is connected to the separation roller shaft 61 a via the roller support portion 135. The rotation support member 134 is rotatable in the XZ plane around the rotation axis of the secondary transfer roller 62 with respect to the fixed side plate 150. One end of the groove 136 on the secondary transfer roller 62 side is attached to the end of the groove 136. A tension spring 137 as a biasing member is attached.
The tension spring 137 has an end portion on the secondary transfer roller 62 side fixed to the groove portion 136, and an opposite end portion fixed to the roller support portion 135.
The roller support portion 135 is urged by the tension spring 137 in the direction opposite to the secondary transfer roller 62 side along the groove 136, that is, in the direction of separating the separation roller shaft 61a and the rotation shaft of the secondary transfer roller 62. .

A support spring 140 that connects the fixed side plate 150 and the rotation support member 134 and urges the rotation support member 134 in the −θ direction, which is an urging direction, is connected to the upper portion of the rotation support member 134.
In the initial state shown in FIG. 2 where the centers of the rotation shafts of the secondary transfer roller 62 and the separation roller 61 are aligned along the Z axis, in other words, the groove 136 is parallel to the Z axis, the outer peripheral surface of the inclined member 131 131d and the stopper surface 150b of the fixed side plate 150 are brought into contact with each other and suppressed.
Since the outer peripheral surface 131d and the stopper surface 150b come into contact with each other and press against each other, the rotational support member 134 maintains the initial state because it balances the rotational force acting in the −θ direction.

When a belt shift occurs in the secondary transfer belt 60, that is, when a force is applied that causes the end of the secondary transfer belt 60 to move in the + Y direction due to vibration or the like, the Y direction of the secondary transfer belt 60 The shift detection member 130 is pushed in the + Y direction by the movement to.
As shown in FIG. 5, the movement of the deviation detecting member 130 releases the contact between the stopper surface 150b and the outer peripheral surface 131d, and the contact position between the contact portion 150a and the inclined surface 131a is the inclined surface. It moves to the −Y direction side of 131a.

By such a change in the contact position, the separation roller shaft 61a is inclined downward from the initial position by an inclination angle α that is a belt return angle.
When the separation roller shaft 61a is inclined by the inclination angle α, the separation roller shaft 61a and the rotation shaft of the secondary transfer roller 62 are inclined to each other.
In the inclined state, as shown in FIG. 6, the separation roller shaft 61a moves outward in the radial direction perpendicular to the θ direction. As a result, the roller support 135 moves radially outward along the groove 136, and the rotation support member 134 rotates in the θ direction about the rotation axis of the secondary transfer roller 62.
At this time, the roller support portion 135 moves in the −X direction according to the rotation of the rotation support member 134. Note that the roller support 135 can move in the X direction, the Z direction, or both.

In the inclined state, as shown in FIG. 7, the secondary transfer belt 60 moves in the −Y direction by Ltanα every time the unit distance L advances in the Z direction. In other words, the secondary transfer belt 60 moves in a direction to cancel the inclination angle α. The amount of movement of the secondary transfer belt 60 is referred to as a reverse amount.
At this time, the shift back amount increases in proportion to the inclination angle α. Therefore, when the force by which the secondary transfer belt 60 pushes the shift detection member 130, that is, the original belt shift increases, the secondary transfer belt 60. The amount of return will also increase.
Due to such movement of the secondary transfer belt 60, the belt transfer that originally occurs in the secondary transfer belt 60 and the belt shift that occurs when the separation roller shaft 61a is inclined by the inclination angle α are balanced at the secondary transfer position. The position of the belt 60 converges.
In the present embodiment, the case where the secondary transfer belt 60 is inclined by the inclination angle α from the initial state has been described, but the separation is similarly performed when the secondary transfer belt 60 is further inclined from the inclination angle by the inclination angle α. The roller shaft 61a is inclined and converges at another balance position.

  With this configuration, the transfer conveyance unit 6 in the present embodiment operates as a reliable and reliable belt control device with a simple configuration and low cost.

  However, in the above-described structure in which the separation roller shaft 61a is inclined to suppress the belt shift, the interference between the rotation support member 134 and the fixed side plate 150 in the inclined state is a concern only by movably supporting the separation roller shaft 61a. Is done. That is, in the inclined state, the contact area between the rotation support member 134 and the fixed side plate 150 may increase.

  Due to such an increase in the contact area, the friction on the contact surface between the rotation support member 134 and the fixed side plate 150 becomes a resistance, and the force required to rotate the rotation support member 134 also increases. There is a concern that a large load is applied to the end.

FIG. 8 shows the result of a durability test in which the load applied to the end of the secondary transfer belt 60 due to an increase in the contact area between the rotation support member 134 and the fixed side plate 150 in the inclined state is evaluated. The durability test was performed to determine whether or not there was a crack at the end of the secondary transfer belt 60 when the secondary transfer belt 60 was idled by a distance equivalent to 1.2 million sheets (corresponding to a belt travel distance of 630 km). In the case where there is a crack, the evaluation is ×, and in the case where there is no crack, the evaluation is ○.
As is clear from FIG. 8, when the contact area between the rotation support member 134 and the fixed side plate 150 is 0.5 mm ² or less, the durability is improved.

In the present embodiment, the transfer conveyance unit 6 includes a protrusion 132 provided between the fixed side plate 150 and the rotation support member 134.
In this embodiment, the protrusion 132 is a hemispherical convex portion having a radius of 1 mm, and is provided on the surface of the rotation support member 134 facing the fixed side plate 150, and makes point contact with the fixed side plate 150.
With this configuration, the contact area between the rotation support member 134 that supports the separation roller shaft 61a and the fixed side plate 150 is not increased even when the separation roller shaft 61a is inclined, so that the load applied to the end of the secondary transfer belt 60 is reduced. Reduce.
Also, with this configuration, the protrusion 132 makes point contact with the fixed side plate 150 while maintaining the total contact area at 0.5 mm ² or less, so the load applied to the end of the secondary transfer belt 60 is reduced to 2 The durability of the next transfer belt 60 is improved.

Further, as shown in FIG. 9, simply by providing the protrusion 132 so as to make point contact between the fixed side plate 150 and the rotation support member 134, the protrusion is formed when the separation roller 61 is inclined. There is a possibility that the contact between the rotation support member 134 and the rotation support member 134 is released.
In the present embodiment, the projecting portion 132 is in point contact with the fixed side plate 150 even when the separation roller 61 is inclined, and maintains a substantially parallel space between the fixed side plate 150 and the rotation support member 134.

Specifically, when the maximum inclination angle γ of the separation roller shaft 61a and the length r of the separation roller shaft 61a are set, the protrusion 132 is within a distance of rsin γ from the center position of the separation roller shaft 61a in the initial state. Are arranged as follows.
The protrusion 132 is installed so as to be within a range determined by the maximum inclination angle γ and the length r of the separation roller shaft 61a, so that the protrusion 132 is always in point contact with the fixed side plate 150. .
With this configuration, the contact area between the rotation support member 134 that supports the separation roller shaft 61a and the fixed side plate 150 is not increased even when the separation roller shaft 61a is inclined, so that the load applied to the end of the secondary transfer belt 60 is reduced. Reduce.

The protrusion 132 may be formed on one of the fixed side plate 150 and the rotation support member 134 and may be in point contact with the other one of the fixed side plate 150 and the rotation support member 134.
In other words, in the present embodiment, the protrusion 132 is disposed on the surface of the rotation support member 134 that faces the fixed side plate 150, but may be provided on the fixed side plate 150 side. In such a configuration, the protrusion 132 is in point contact with either the fixed side plate 150 or the rotation support member 134.

The protrusions 132 are also preferably disposed on both sides across a line connecting the separation roller shaft 61a and the rotation shaft of the secondary transfer roller 62.
As described above, the distance between the fixed side plate 150 and the rotation support member 134 is kept constant by arranging the separation roller shaft 61a on both sides of the line connecting the rotation shaft of the secondary transfer roller 62. The posture of the rotation support member 134 is stabilized.
With this configuration, the protrusion 132 can stably maintain the fixed side plate 150 and the rotation support member 134 substantially in parallel while maintaining a point contact with either the fixed side plate 150 or the rotation support member 134 at all times. The load applied to the end of the secondary transfer belt 60 is reduced.

Further, it is desirable that the protrusions 132 are arranged symmetrically with respect to the separation roller shaft 61a.
With this configuration, the protrusion 132 can stably maintain the fixed side plate 150 and the rotation support member 134 substantially in parallel while maintaining a point contact with either the fixed side plate 150 or the rotation support member 134 at all times. The load applied to the end of the secondary transfer belt 60 is reduced.

In addition, as shown in FIG. 10, the inclined member 131 is disposed with its end portion separated from the fixed side plate 150 in the initial state so that it can move by Zd in the Y direction.
With such a configuration, the maximum movable distance of the inclined member 131 is suppressed to Zd, so that the maximum inclination angle γ can be determined only by the interval.

  The preferred embodiments of the present invention have been described above. However, the present invention is not limited to the specific embodiments, and the present invention described in the claims is not specifically limited by the above description. Various modifications and changes are possible within the scope of the above.

  For example, the image forming apparatus is a so-called tandem color image forming apparatus in the present embodiment, but may be a monochrome image forming apparatus.

  In the present embodiment, the protruding portion has a hemispherical shape. However, the protruding portion is not limited as long as it is a protruding and point-contacting member.

In the present embodiment, the transfer / conveyance apparatus has two protrusions, but the transfer / conveyance apparatus is not limited in number as long as it has a plurality of point-contact points.
In the above embodiment, two protrusions are provided on the rotation support member side. However, all of the protrusions may be provided on the fixed side plate side, or provided separately on the rotation support member side and the fixed side plate side. It is also good.

  The effects described in the embodiments of the present invention are only the most preferable effects resulting from the present invention, and the effects of the present invention are limited to those described in the embodiments of the present invention. is not.

DESCRIPTION OF SYMBOLS 1 Paper feeder 3 Transfer belt 6 Belt control apparatus (transfer conveyance means)
7 Fixing Unit 8 Belt Cleaning Device 12 Registration Roller Pair 60 Belt Member (Secondary Transfer Belt)
61 Movable rotating body (separation roller)
61a Rotating shaft (separation roller shaft)
62 Secondary transfer roller 100 Image forming apparatus 130 Deviation detecting member 131 Inclined member, 131a Inclined surface, 131d Outer peripheral surface 132 Protruding portion 134 Swing support member (rotation support member)
135 Roller support part 136 Groove part 137 Tension spring 150 Fixed side plate

JP 2014-095737 A JP 2012-198293 A JP 2011-186151 A Japanese Patent No. 4586595 JP 2012-103286 A JP 2010-230958 A

Claims (4)

An endless belt member;
A plurality of rotating bodies wound around the belt member;
A swing support member that swingably supports one of the plurality of rotating bodies as a movable rotating body;
Fixed stationary side plate,
A deviation detecting member that is disposed at an end of the movable rotating body and detects movement of the belt member in the rotational axis direction of the movable rotating body;
An inclination member disposed between the shift detection member and the swing support member, for inclining the rotation axis of the movable rotating body by the movement of the belt member in the rotation axis direction;
A plurality of protrusions formed between the fixed side plate and the swing support member,
Each of the plurality of protrusions is a belt control device that makes point contact with either the fixed side plate or the swing support member. The belt control device according to claim 1,
The protrusions are in point contact with either the fixed side plate or the swing support member even when the movable rotating body is tilted, and maintain substantially parallel between the fixed side plate and the swing support member. A belt control device. The belt control device according to claim 1 or 2,
The belt control device according to claim 1, wherein the protrusion is formed symmetrically with respect to the rotation axis.   An image forming apparatus comprising the belt control device according to claim 1.

Images