JP2020118957A - Belt device, transfer device, and image forming apparatus - Google Patents

Abstract

To provide a belt device that can reduce scraping of a belt end face and a belt skew detection member.SOLUTION: A belt device comprises: an endless belt member 3; a plurality of support rollers 5 that stretch and support the belt member 3; and a shaft displacement mechanism that displaces a position of a rotation shaft of any one of the plurality of support rollers 5. The shaft displacement mechanism includes: a rotatable butting rotating body 44 that can move in an axial direction of the support rollers 5 when the belt member 3 moves in the axial direction, and against which a belt end is butted; a belt skew detection member 30 that can move and rotate with respect to the roller rotation shafts by being pushed by the belt butting rotating body 44; and a shaft inclination member 31 that can move with respect to the roller shafts by being pushed by the belt skew detection member 30, and has an inclined surface inclined with respect to a belt surface.SELECTED DRAWING: Figure 4

Description

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

Conventionally, there is known a belt device including an endless belt member, a plurality of support rollers that stretches and supports the belt member, and an axial displacement mechanism that displaces a position of a rotation shaft of any one of the plurality of support rollers. Has been.
For example, in Patent Document 1, the shaft displacement mechanism is pushed by a belt deviation detection member that is axially movable and rotatable when the belt moves in the axial direction of the support roller, and a belt deviation detection member. Thus, there is disclosed a belt device including a non-rotatable shaft inclination member that is movable with respect to the roller shaft and has an inclined surface that is inclined with respect to the belt surface.

However, in the belt device of Patent Document 1, there is a fear that abrasion may occur due to contact between the belt end surface and the belt deviation detection member, and the abrasion powder may adhere to the peripheral surface of the belt.

In order to solve the above-mentioned problems, a belt device according to a first aspect of the invention provides an endless belt member, a plurality of support rollers that stretch and support the belt member, and a position of a rotary shaft of any one of the plurality of support rollers. An axial displacement mechanism for displacing the axial displacement mechanism, wherein the axial displacement mechanism is movable in the axial direction when the belt member is moved in the axial direction of the support roller, and a rotatable butting rotary member with which a belt end portion abuts. And a belt deviation detection member that can be moved and rotated with respect to the roller rotation axis by being pushed by the belt abutment rotating body, and can be moved with respect to the roller axis by being pushed by the belt deviation detection member, and the belt surface And a non-rotatable shaft tilting member having a tilted surface that is tilted with respect to.

According to the invention of claim 1, it is possible to reduce the abrasion and the adhesion of the abrasion powder to the peripheral surface of the belt.

FIG. 1 is a schematic configuration diagram showing an example of an image forming apparatus. FIG. 3 is a schematic diagram of the configuration of an axis tilting mechanism of the intermediate transfer belt device immediately after assembly. FIG. 3 is a schematic view of the coaxial tilting mechanism in a state where a belt shift is generated. FIG. 3 is a sectional view taken along line AA in FIG. 2. FIG. 4 is a sectional view taken along line AA in FIG. 3. 6A is a perspective view of the shaft tilting member 31, and FIG. 6B is a view seen from the axial direction. FIG. 5 is an explanatory diagram of a belt deviation of the intermediate transfer belt. (A) is sectional drawing of a belt deviation detection member, (b) is a front view of a belt abutment rotary body. (A) is a front view of a belt butting rotary body of a modification, (b) is a right side view, (c) is a rear view.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a schematic configuration diagram showing an example of an image forming apparatus configured as a printer. The image forming apparatus shown here is composed of a plurality of photoconductors arranged in a main body casing thereof. Four fourth photoconductors 1a, 1b, 1c, 1d are provided. Toner images of different colors are formed on the respective photoconductors, and in the example shown in FIG. 1, a black toner image, a magenta toner image, and a cyan toner image are formed on these photoconductors 1a, 1b, 1c, and 1d. And a yellow toner image are respectively formed.

Each of the photoconductors 1a, 1b, 1c, 1d shown in FIG. 1 is formed in a drum shape, but an endless belt-shaped photoconductor wound around a plurality of rollers and driven to rotate can also be used. ..

An intermediate transfer belt 3 configured as an intermediate transfer member is arranged so as to face the first to fourth photoconductors 1a, 1b, 1c, and 1d, and each of the photoconductors 1a, 1b, 1c, and 1d is of the intermediate transfer belt 3. It is in contact with the surface. The intermediate transfer belt 3 shown here is wound around a driving roller 4, a tension roller 5, and an inlet roller 7, and one of these supporting rollers, for example, the supporting roller 4 is a driving roller driven by a driving source. The intermediate transfer belt 3 is rotationally driven in the arrow A direction by driving the roller.

The intermediate transfer belt 3 may have a multi-layer structure or a single-layer structure, but if it has a multi-layer structure, the base layer is made of, for example, a fluororesin, a PVDF sheet, or a polyimide-based resin having a low elongation, and the surface thereof is smooth such as a fluororesin. Those coated with a good coat layer are preferable. If it is a single layer, it is preferable to use a material such as PVDF, PC, or polyimide.

The configuration for forming a toner image on the photoconductors 1a, 1b, 1c, 1d and the configuration for transferring each toner image onto the intermediate transfer belt 3 are substantially the same, and the color of each toner image formed is the same. Is only different. Therefore, only the configuration and action of forming a black toner image on the first photoconductor 1a and transferring the toner image onto the intermediate transfer belt 3 will be described.

The photoconductor 1a is rotationally driven counterclockwise as shown by the arrow in FIG. 1, and at this time, the surface of the photoconductor is irradiated with light from the charge eliminating device to initialize the surface potential of the photoconductor 1a. The initialized surface of the photoconductor is uniformly charged by the charging device 8 to a predetermined polarity, in this example, a negative polarity. This charged surface is irradiated with the light-modulated laser beam emitted from the exposure device 9, and an electrostatic latent image corresponding to the writing information is formed on the surface of the photoconductor 1a.

In the image forming apparatus shown in FIG. 1, the exposure device 9 including a laser writing device that emits a laser beam is used, but it is also possible to use an exposure device having an LED array and an image forming unit.

The electrostatic latent image formed on the photoconductor 1 a is visualized as a black toner image as it passes through the developing device 10. On the other hand, inside the intermediate transfer belt 3, a transfer roller 11 is arranged facing the photoconductor 1a with the belt interposed therebetween. The transfer roller 11 contacts the back surface of the intermediate transfer belt 3, and an appropriate transfer nip between the photoconductor 1 a and the intermediate transfer belt 3 is secured.

A transfer voltage having a polarity opposite to the toner charging polarity of the toner image formed on the photoconductor 1a, that is, a positive polarity in this example, is applied to the transfer roller 11. As a result, a transfer electric field is formed between the photoconductor 1a and the intermediate transfer belt 3, and the toner image on the photoconductor 1a is electrostatically transferred onto the intermediate transfer belt 3 which is rotationally driven in synchronization with the photoconductor 1a. Be transcribed. The transfer residual toner attached to the surface of the photoconductor 1a after the toner image is transferred to the intermediate transfer belt 3 is removed by the cleaning device 12, and the surface of the photoconductor 1a is cleaned.

In the same manner, magenta toner images, cyan toner images, and yellow toner images are formed on the second to fourth photoconductors 1b, 1c, and 1d, respectively, and the toner images of the respective colors are transferred as black toner images. Electrostatic transfer is sequentially performed on the transferred intermediate transfer belt 3.

At this time, there are two types of modes, that is, a full color mode in which toner images of four colors are used and a black monochrome mode in which only black monochrome is used. In the full color mode, the intermediate transfer belt 3 and the four-color photoconductors come into contact with each other, and the toners of all four colors are transferred onto the intermediate transfer belt. On the other hand, in the black monochromatic mode, only the black photoconductor contacts the intermediate transfer belt, and only the black toner is transferred to the intermediate transfer belt. At this time, the intermediate transfer belt is not in contact with the magenta, cyan, and yellow photoconductors 1b, 1c, and 1d, and the primary transfer rollers 11b, 11c, and 11d are separated from the photoconductor by the contact/separation mechanism.

On the other hand, as shown in FIG. 1, a paper feeding device 14 is arranged in the lower part of the apparatus main body, and the paper feeding device 14 rotates a paper feeding roller 15 so that a recording medium P made of, for example, transfer paper is moved in the direction of arrow B. Sent out. The recording medium P sent out is a portion of the intermediate transfer belt 3 wound around the support roller 4 by the registration roller pair 16 at a predetermined timing, and a secondary transfer roller 17 which is an example of a transfer device which is opposed to the portion of the intermediate transfer belt 3. Delivered between and. At this time, a predetermined transfer voltage is applied to the secondary transfer roller 17, whereby the synthetic toner image on the intermediate transfer belt 3 is secondarily transferred to the recording medium P.

The recording medium P to which the synthetic toner image has been secondarily transferred is further conveyed upward and passes through the fixing device 18. At this time, the toner image on the recording medium P is fixed by the action of heat and pressure. The recording medium P that has passed through the fixing device 18 is ejected to the outside of the image forming apparatus via a paper ejection roller pair 19 provided in the paper ejection unit. The transfer residual toner adhering to the intermediate transfer belt 3 after the toner image transfer is removed from the intermediate transfer belt 3 by the cleaning blade 21, and is conveyed to the waste toner container.

Next, a belt deviation control mechanism in an intermediate transfer belt device (unit) including the intermediate transfer belt 3 in this image forming apparatus will be described.
2. Description of the Related Art Conventionally, various endless belts have been used in image forming apparatuses as a latent image carrier, an intermediate transfer member, a recording medium conveying member, an image fixing member, and the like. This type of endless belt is configured to run in a certain direction while being stretched over at least two rollers. However, there are problems such as material, accuracy of related parts, and deterioration of related parts over time. As a result, a so-called belt deviation occurs in which the belt moves in a direction orthogonal to the traveling direction of the belt. When this belt deviation occurs, a transfer image on a recording medium such as a recording sheet may be misaligned, or a problem such as a belt breakage due to the belt being disengaged from the tension roller may occur. Therefore, it is necessary to prevent or correct the belt deviation.

Therefore, conventionally, a method has been proposed in which the movement of the belt toward the belt is detected by a detection member, and the roller on which the belt is stretched is displaced by a roller displacement member based on the detection result to correct or prevent the movement of the belt. ing. For example, in Patent Document 1, at least one end portion of the tension roll has a meandering correction roll that movably holds the belt in a direction orthogonal to the pressing direction of the belt and corrects the belt meandering. An outer circumference of the rotator having a surface movably arranged along the axial direction and having a surface in contact with the end portion of the transfer belt and an inclined surface whose outer diameter changes along the axial direction of the meandering correction roll. A belt meandering correction device having a fixed guide member arranged so as to abut the surface has been proposed. In this belt meandering correction device, the meandering belt ends are brought into contact with the rotating body, and the meandering correction roll is inclined by the movement of the rotating body due to the meandering of the belt, whereby the meandering is corrected.

The belt deviation control mechanism of the intermediate transfer belt device according to the present embodiment basically employs the belt meandering correction device described in Patent Document 1. This is an axial tilting method, and by tilting the rotation axis of the tension roller 5 which is one of the supporting rollers that stretches the intermediate transfer belt 3, the belt shift range of the intermediate transfer belt 3 can be regulated within a predetermined regulation range. Is configured.

FIG. 2 is a schematic view of the configuration of the shaft tilting mechanism of the intermediate transfer belt device immediately after assembly, as viewed from the axial direction of the tension roller 5. FIG. 3 is a schematic view of the shaft inclining mechanism in a state where the belt is biased, as viewed from the axial direction of the tension roller 5.

The tension roller 5 of the present embodiment is supported on both ends of the rotary shaft 5a by the rotation support portions 29 that displace the tension rollers 5 respectively. The rotation support portion 29 may be provided only on one end side instead of both ends. The rotation support portion 29 supports the tension roller 5 and applies tension to the tension roller bearing member 33, a tension spring 32 that applies tension to the tension roller bearing member 33, and a frame 37 that is rotatably supported by a rotation shaft 36. The member 34 is provided. In addition, a support spring 40 that supports the rotation support member 34 is also provided, and is urged clockwise by the support spring 40 in FIG.

FIG. 4 is a sectional view taken along line AA in FIG. FIG. 5 is a sectional view taken along line AA in FIG. The following structure is employed to incline the tension roller 6 supported so as to be inclined by using the offset force of the intermediate transfer belt 3 by utilizing the offset force of the intermediate transfer belt 3. A belt deviation detection member 30 that comes into contact with the end surface of the tension roller 5 and a shaft inclination member 31 on the outer side of the rotation shaft 5a of the tension roller 5 having a diameter smaller than that of the tension roller 5 are axially movable. It is provided.

The frame 37 is provided with a shaft guide member 35, and when the shaft tilting member 31 and the shaft guide member 35 contact each other, the rotational position of the rotation support member 34 is held against the biasing force of the support spring 40. In these figures, what is interposed between the end surface of the intermediate transfer belt 3 and the belt deviation detection member 30 is a belt abutting rotary member 44 that is a feature of this embodiment. This will be described later in detail. The alternate long and short dash line in FIG. 4 indicates the YZ plane, and the alternate long and two short dashes line indicates the center line of the tension roller 5. Immediately after the assembling shown in FIG. 4, the right side in the figure is inclined so as to face upward. This is a state in which the intermediate transfer belt 3 first intentionally generates a deviation toward the right and converges the deviation.

As shown in FIGS. 2 and 3, the rotation shaft 36 that pivotally supports the rotation support member 34 sandwiches the bisector L of the angle formed by the intermediate transfer belt 3 and contacts the shaft inclination member 31 and the shaft guide member 35. It is located on the opposite side of the section. By doing so, a force acts on the shaft tilting member 31 so as to move toward the shaft guide member 35, and the shaft tilting member 31 and the shaft guide member 35 can be brought into contact with each other. If the rotary shaft 36 is positioned such that the shaft tilting member 31 and the shaft guide member 35 are always in contact with each other, it is possible to eliminate the support spring 40 from the viewpoint of ensuring contact between the two.

FIG. 6A is a perspective view of the shaft tilting member 31, and FIG. 6B is a view seen from the axial direction. The shaft tilting member 31 has a contact portion 31a, a tilting portion 31b, and a stopper portion 31c. The contact portion 31a has a cylindrical shape, the inclined portion 31b has a conical curved surface, and the stopper portion 31c has a cylindrical shape. The inclined portion 31b has a conical curved surface for the following two reasons. One is to prevent the position of the tension roller 5 from changing even when the shaft tilting member partially rotates. The second is to make the contact with the shaft guide member 35 point contact.

By making the point contact with the shaft guide member 35, the frictional force between the inclined portion 31b of the shaft tilt member 31 and the shaft guide member 35 decreases. Therefore, the shaft inclination member 31 and the belt deviation detection member 30 move smoothly, and the force acting between the intermediate transfer belt 3 and the belt deviation detection member 30 can be reduced. Therefore, the life of the belt against cracks is extended. The shaft inclination angle α (see FIG. 4) is 30°, and the material of the shaft inclination member is POM. Further, the shaft tilting member 31 has a flat rotation stopping portion 31d on both side faces, for example, a rotation stopping portion integrally provided on the tension roller bearing member 33 is brought into contact with the tension roller 5 for rotatably supporting the shaft tilting member 31. The non-rotating posture is set on the rotating shaft 5a.

The shaft guide member 35 has linear corners, and the corners have a curved shape, here, an R shape. By having the linear corners, the shaft tilting member 31 can maintain point contact at the same height as the guide portion even if the belt circumference changes due to environmental changes and the tension roller moves in the belt traveling direction. ..

Next, the operation of the above belt deviation control mechanism will be described.
In FIG. 4, when the drive roller 4 starts to rotate, the tension roller 5, which is a driven roller around which the intermediate transfer belt 3 is wound, also starts to rotate. At the same time, the belt abutting rotary member 44, which is in contact with the end portion of the intermediate transfer belt 3, and the belt deviation detection member 30 also start to rotate.

In this state, when the deviation of the intermediate transfer belt 3 toward the right direction in FIG. 4 occurs due to the influence of the parallelism between the members, the belt abutting rotary member 44 and the belt deviation detection member 30 also move toward the intermediate transfer belt 3. Move in the same direction in sync with the leaning. Since the shaft tilting member 31 is also in contact with the belt deviation detection member 30 at the contact portion 31a, it moves in the same direction.

At this time, since the inclined portion 31b of the shaft inclination member 31 is in contact with the shaft guide member 35, the tension roller 5 is inclined downward in FIG. 4 with the other end of the rotary shaft 5a of the tension roller 5 as a fulcrum. It becomes the state of 5. The inclination of the tension roller 5 causes the intermediate transfer belt 3 to move toward the left in the drawing, and the belt deviation can be reduced and converged. Even if the intermediate transfer belt 3 deviates in the opposite direction, each member moves in the opposite direction from the state shown in FIG. 5 to the state shown in FIG.

The principle of the belt deviation due to the tilting of the tension roller shaft is as follows. Assuming that the intermediate transfer belt 3 is a rigid body, and focusing on an arbitrary point on the intermediate transfer belt 3 before entering the tension roller 5, the intermediate transfer belt 3 wound around a plurality of rollers is completely In a horizontal or parallel state, the one point rotates on the tension roller without moving in the axial direction of the tension roller as the tension roller 5 rotates, so that the belt does not lean.

On the other hand, when one tension roller shaft is tilted with respect to the other roller shaft, assuming that the inclination angle is β, the one point on the intermediate transfer belt 3 corresponds to tan β with the rotation of the tension roller 5. Therefore, the intermediate transfer belt moves to a position axially moved with respect to the entering direction of the intermediate transfer belt. FIG. 7 is an explanatory diagram of the belt deviation of the intermediate transfer belt 3. In FIG. 7, when the tension roller 5 is tilted downward by an inclination angle β with respect to the drive roller 4 arranged on the upstream side when viewed in the direction in which the intermediate transfer belt 3 enters the tension roller 5, the intermediate transfer belt 3 is moved. It is possible to shift the tension roller 5 leftward in the drawing by tan β in accordance with the rotation of the tension roller 5.

Since this action is a physical action, when the rotating shaft 5a of the tension roller 5 is tilted upward from the horizontal direction, the intermediate transfer belt 3 is moved to the right in the figure in accordance with the rotation of the tension roller 5. It becomes possible to make it close.

Further, the deviation amount of the intermediate transfer belt is proportional to the inclination angle α. That is, the greater the inclination angle α, the greater the deviation amount of the intermediate transfer belt, and the smaller the inclination angle α, the smaller the deviation amount of the belt. Therefore, for example, when the intermediate transfer belt 3 acts to move to the right in FIG. 7 and the shaft tilting member 31 moves to tilt the rotary shaft 5a of the tension roller 5 downward, the intermediate transfer belt 3 The rotation shaft 5a of the tension roller 5 is inclined due to or proportional to the deviation. For this reason, the deviation of the intermediate transfer belt 3 and the action of correcting the intermediate transfer belt 3 in the opposite direction, which occurs due to the inclination of the rotary shaft 5a of the tension roller 5, are converged at the position where they are balanced. Can be done.

Even if the intermediate transfer belt 3 further moves to the left or right at this balanced position, the axial tilting member 31 similarly moves due to the belt deviation or in proportion to the rotation of the tension roller 5. The inclination of the shaft 5a changes, and the deviation of the intermediate transfer belt 3 can be converged again. That is, by giving the rotation shaft 5a of the tension roller 5 an inclination according to the amount of movement of the intermediate transfer belt 3, the deviation of the intermediate transfer belt 3 can be converged. As described above, according to the present embodiment, it is possible to achieve the belt deviation prevention which is highly reliable and reliable and has a low cost even though it has a simple structure.

Next, the belt abutting rotary member 44, which is a characteristic part of the present embodiment, will be described.
In the conventional configuration that does not use the belt abutting rotating body 44, the belt deviation detection member 30 is in direct contact with the end surface of the intermediate transfer belt 3 and is pressed, so that stress is always applied. The end surface of the belt is the weakest part of the belt, and in actual observation, it was observed that the end portion of the belt was occasionally broken. If there is a linear velocity difference between the member abutting the end of the intermediate transfer belt and the end of the intermediate transfer belt, they may be damaged and scraped. This is because the belt deviation detection member 30 is in contact with the non-rotating shaft tilting member 31, so that the shaft tilting member 31 serves as a brake for rotation, and a linear velocity difference with the intermediate transfer belt 3 is likely to occur. There is also a problem that the belt deviation detection member 30 is scraped off, and scraped powder adheres to the surroundings to cause scratches.

Therefore, in the present embodiment, the belt meandering correction mechanism performs the meandering correction (belt deviation regulation control) without being scraped by the belt, thereby achieving a long life of the belt device without adhering shavings to the surroundings. Provided are a low-cost, compact belt driving device and an image forming apparatus using the belt driving device. Specifically, in order to reduce the linear velocity difference between the intermediate transfer belt 3 and a member that directly contacts the intermediate transfer belt 3, as a member that the end surface of the intermediate transfer belt 3 directly contacts, a relative belt deviation detection member 30 is provided. A belt abutting rotary member 44 is provided so that the belt can be freely rotated. The belt abutment rotating body 44 is not fixed to the belt deviation detecting member 30, but is rotatably attached to the belt deviation detecting member. The belt abutting rotary member 44 abuts on the end portion of the intermediate transfer belt 3 and rotates together with the intermediate transfer belt 3 due to the frictional force from the end portion of the belt. On the other hand, the belt deviation detection member 30 generates a rotational force that rotates with the belt abutting rotary member 44 due to the frictional force with the belt abutting rotary member 44. However, since the non-rotating shaft inclination member 31 is in contact with the belt deviation detection member 30, a braking force is generated in the rotation of the belt deviation detection member 30. Therefore, the belt abutting rotary member 44 rotates relative to the belt deviation detection member 30.

Specifically, as shown in the sectional view of FIG. 8A, the belt deviation detection member 30 includes a small-diameter shaft portion 30a slightly smaller than the diameter of the roller portion of the tension roller 5, and a large-diameter collar. It has a portion 30b and a through hole 30c. The collar portion 30b includes a circular end surface portion 30d that stands upright from the small diameter shaft portion 30a, and a taper surface portion 30f that connects the outer peripheral edge of the end surface portion 30d and the maximum diameter portion 30e of the collar portion. In FIG. 8A, the belt abutting rotating body 44 is also shown by an imaginary line (two-dot chain line).

As shown in the front view of FIG. 8B, the belt abutting rotary body 44 has a central hole portion 44a having a diameter D1 slightly larger than the outer diameter of the small diameter shaft portion 30a. The diameter D2 of the circular outer edge is set to be larger than the sum of the outer diameter of the roller portion of the tension roller 5 and the thickness of the intermediate transfer belt 3. The small-diameter shaft portion 30a of the belt deviation detection member 30 is inserted into the center hole 44a and held by the belt deviation detection member 30. In other words, a state in which the upper region in the gravity direction on the inner peripheral surface of the center hole portion 44a of the belt abutting rotary member 44 is held in contact with the region in the gravity direction upper direction of the small diameter shaft portion 30a of the belt deviation detection member 30 is held. Become. Further, the belt abutment rotating body 44 is in non-fixed contact with the end surface portion 30d of the belt deviation detection member 30. As shown in FIG. 4, the belt abutting rotary member 44 is sandwiched between the end surface of the intermediate transfer belt 3 and the end surface portion of the belt deviation detection member 30.

When the belt abutting rotary member 44 is not provided, the linear speed difference between the intermediate transfer belt and the belt deviation detection member is 0.7 in terms of ratio (belt deviation detection member linear speed/intermediate transfer belt linear speed), whereas the intermediate transfer belt is When the belt abutting rotary member 44 is arranged between the belt deviation detecting members, the linear velocity difference between the intermediate transfer belt and the belt abutting rotating member 44 is improved to about 0.9 in terms of ratio (belt deviation detecting member/intermediate transfer belt). did. The linear velocity difference can be improved in any case, although it varies depending on the force toward the belt, the surface roughness of the belt end portion, and the cut step that is inevitably generated by cutting the intermediate transfer belt to a predetermined width.

By providing the configuration in which the belt abutting rotating body 44 is provided between the intermediate transfer belt 3 and the belt deviation detection member 30, the linear velocity difference between the intermediate transferring belt 3 and the belt abutting rotating body 44 becomes small, and the intermediate transfer Damage to the belt 3 and the belt abutting rotary member 44 is reduced. The reason is as follows.

With the conventional configuration, since the belt deviation detection member 30 is in contact with the non-rotating shaft tilt member 31 and the intermediate transfer belt 3, it is likely to receive resistance, and there is a gap between the intermediate transfer belt 3 and the belt deviation detection member 30. It is easy to get a difference in linear velocity. Therefore, the intermediate transfer belt 3 and the belt deviation detection member 30 are easily damaged.

On the other hand, in the configuration of the present embodiment, since the belt abutment rotating body 44 is in contact with the rotating belt deviation detection member 30 and the intermediate transfer belt 3, the intermediate transfer belt 3 and the belt abutting rotating body 44. It is hard to get a linear velocity difference between and. Therefore, the intermediate transfer belt 3 and the belt butting rotary member 44 are not easily damaged. As a result, in the configuration of this embodiment, shavings are less likely to be generated between the intermediate transfer belt 3 and the belt abutting rotary member 44.

The shape of the belt abutting rotary member 44 may be a hollow cylindrical shape as shown in FIG. 8B. However, in the case of a thin plate, since it is created by punching, burrs at the time of molding will have burrs. The burr side (that is, the side having a rough surface) may be opposite to the contact side with the intermediate transfer belt 3 so as not to contact the intermediate transfer belt 3 and damage the intermediate transfer belt 3. That is, the belt abutting rotary body 44 is installed such that the surface of the belt abutting rotary body 44 opposite to the surface in contact with the intermediate transfer belt 3 has a rough surface. In order to distinguish which side is the burr side, it is desirable to make the front and back sides asymmetrical as shown in FIG. 9, for example. According to this, the front side and the back side can be easily distinguished, and the burr side can be easily assembled with the side opposite to the contact side with the intermediate transfer belt 3.

9A is a front view showing the front surface 44b, FIG. 9B is a right side view, and FIG. 9C is a rear view showing the back surface 44c. The portion indicated by reference numeral 44d in (b) is a burr (burr by punching) schematically shown. The assembler views the surface 44b having the shape shown in FIG. 9(a) with respect to the end surface portion 30d of the belt deviation detection member 30 before being attached to the rotary shaft 5a of the tension roller 5, and the belt in the center hole portion 44a. The small-diameter shaft portion 30a of the deviation detecting member 30 is attached while being inserted.

As a specific example, with respect to a hollow cylindrical thin plate having an outer diameter D2 of φ22.6, an inner diameter D1 of φ19.8, and a thickness of 0.2, as shown in FIG. A cutout having an arc shape (the cut line corresponds to a chord) is formed by the arcs 44e and 44f. The lengths of the cut lines 44c and 44d are 5 mm and 7.5 mm, which are different from each other and have different bow shapes. As a result, unlike the case where the lengths are the same, the front and back have an asymmetrical shape. When the cut lines 44c and 44d have the same length, for example, when the cut lines 44c and 44d are rotated counterclockwise by 45 degrees around the center of the central hole 44a from the state of (c), they are completely at the surface shown in FIG. 9A. It will have the same shape.

In the illustrated example, when the small diameter shaft portion 30a of the belt deviation detection member 30 is inserted into the center hole 44a while being attached to the end surface portion 30d of the belt deviation detection member 30, as shown in FIG. The shorter cut line 44c of the two cut lines 44c and 44d having different lengths is made horizontal at the upper part, and the portion 44g remaining in an arc shape between the two is set to the upper left position. Such a posture is possible only on the surface. This surface shape can be used as a guide for mounting. Further, the amount of contact with the end surface of the intermediate transfer belt 3 can be reduced by the amount of the arc-shaped notch. Further, since the portion of the cut line (the chord portion) hits the end surface of the intermediate transfer belt 3 and becomes a resistance, the linear velocity difference between the intermediate transfer belt 3 and the belt abutting rotary member 44 can be further reduced.

Of course, the front-back asymmetrical shape is not limited to this shape. The outer diameter of the belt abutting rotary member 44 is larger than the value obtained by adding the outer diameter of the tension roller and the thickness of the belt. However, if the outer diameter is too large, the intermediate transfer belt may be damaged too much. It is preferable that the value obtained by adding the thickness of the intermediate transfer belt 3 to about +3 mm. PET was used as the material of the butting rotor.

Since the belt deviation detection member 30 does not come into contact with the sharp thin film belt, the amount of wear is small, but the belt abutting rotary member 44 that comes into contact with the intermediate transfer belt 3 comes into contact with the sharp thin film belt, and the amount of wear increases. Therefore, the belt deviation detection member 30 may be an inexpensive resin member, but it is preferable that the hardness of the belt abutting rotary member 44 (Rockwell hardness: R125) is harder than that of the belt deviation detection member 30. It is desirable that the hardness of the belt abutting rotary member 44 is not harder than that of the intermediate transfer belt 3 in order to suppress damage to the intermediate transfer belt 3.

If the hardness of the belt abutting rotary member 44 is too hard, the intermediate transfer belt 3 will be greatly damaged and the intermediate transfer belt 3 will be damaged. Further, the material of the belt deviation detection member 30 does not need to be harder than necessary, and it is desirable to set the hardness lower than that of the belt abutting rotary member 44. This is because if the hardness of the belt deviation detection member 30 is increased, the shaft tilting member 31 will be scraped or the cost will be increased. The specific material of the belt deviation detection member 30 is POM (Rockwell hardness: R119), but the hardness of the belt abutting rotary member 44 is harder.

An example of a specific configuration of the tension roller 5 and the intermediate transfer belt of this embodiment will be shown below.
Outside diameter of tension roller: φ20
Tension roller material: Aluminum intermediate transfer belt material: Polyimide intermediate transfer belt Young's modulus: 3400 MPa
Intermediate transfer belt MIT Number of folding endurance tests by rubbing: 500 times Intermediate transfer belt thickness: 60 μm
Intermediate transfer belt linear velocity: 256 mm/s
Belt tension: 1.3N/cm
The method for measuring the folding endurance by the MIT rubbing resistance test is based on JIS-P8115. As a measurement condition, 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/min.

As described above, according to the present embodiment, the belt abutting rotating body is provided between the belt deviation detecting member of the belt meandering correcting mechanism and the belt member, and the linear velocity difference between the belt and the belt abutting rotating body is reduced, Also, by reducing the damage to the belt abutting rotary member, shavings are less likely to be generated between the belt and the belt abutting member. Therefore, the belt meandering correction that suppresses the shavings between the belt and the belt abutting member and prevents the shavings from adhering to the surroundings makes it possible to realize a belt device having a low cost and a long life.

Although the above embodiment is the control for correcting the deviation of the intermediate transfer belt, the mechanism for correcting the belt deviation is a belt other than the intermediate transfer belt, for example, a secondary transfer belt, a paper conveyance belt for secondary transfer. Also, the same effect can be obtained for correction of deviation of the paper transport belt in the direct transfer system, the photoconductor belt when the photoconductor is composed of a belt member, and the like.

1a Bk Photoreceptor 3 Intermediate Transfer Belt 5 Tension Roller 11a Bk Primary Transfer Roller 21 Cleaning Blade 29 Rotation Support Part 30 Belt Deviation Detection Member (Belt Abutment Member)
31 Shaft Inclination Member 32 Tension Spring 33 Tension Roller Support Member 34 Rotation Support Member 35 Guide Member 40 Support Spring 44 Belt Abutment Rotating Body

JP, 2014-95737, A

Claims (6)

An endless belt member,
A plurality of support rollers for stretching and supporting the belt member,
And a shaft displacement mechanism for displacing the position of the rotation shaft of one of the plurality of support rollers,
The axial displacement mechanism,
When the belt member moves in the axial direction of the supporting roller, the rotatable butting rotary body is movable in the axial direction, and the belt end portion abuts.
A belt deviation detection member that can be moved and rotated with respect to the roller rotation axis by being pushed by the belt abutting rotating body,
A belt device comprising: a non-rotatable shaft tilting member that is movable with respect to the roller shaft when pushed by the belt deviation detection member and that has a non-rotatable shaft tilting surface that is tilted with respect to the belt surface. .. The belt device according to claim 1, wherein the belt abutting rotary member has a burr, and the belt abutting side is not the burr side. The belt device according to claim 2, wherein the belt abutting rotating body is asymmetrical on the front and back sides. The belt device according to any one of claims 1 to 3, wherein the hardness of the belt abutting rotary member is higher than the hardness of the belt deviation detection member. A transfer device using the belt device according to claim 1. An image forming apparatus using the belt device according to claim 1 or the transfer device according to claim 5.

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