JP4487606B2 - Belt conveying device and image forming apparatus - Google Patents

Description

  BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a belt conveyance device that conveys an object to be conveyed on an endless belt, and a copier and printer using the belt conveyance device that conveys an object to be conveyed such as a toner image or a recording medium on an endless belt. And the like.

  In an image forming apparatus such as a copying machine or a printer using an electrophotographic system, a toner image or a recording medium (paper, etc.) is carried by an endless belt such as a photosensitive belt, an intermediate transfer belt, a paper conveyance transfer belt, or the like. Some use a belt conveyance device for conveyance. In these belt conveying devices, each endless belt is usually stretched around a plurality of support rolls including drive rolls.

In addition, this type of belt conveyance device may be used in processes that require positional accuracy such as toner image formation and transfer. In such a case, it is necessary to suppress the so-called meandering, in which the endless belt travels in the axial direction of the roll as much as possible. As a measure for suppressing this deviation (meandering), protrusions (hereinafter referred to as “rib members”) are provided along both edges of the inner peripheral surface of the endless belt. The rib member can be formed by, for example, fixing an elongated plate-like member to the inner peripheral surface of the endless belt.
The rotation of the endless belt provided with the rib member is performed in a state where the surface of the rib member on the center side of the endless belt is in contact with the guide surfaces provided at both ends of the roll. Is suppressed.

  FIG. 7 is a schematic view showing an example of a conventional belt conveyance device using an endless belt provided with rib members along both edges of the inner peripheral surface. FIG. FIG. 7B is a schematic cross-sectional view showing a cross-sectional portion of the stretched endless belt, and FIG. 7B is a perspective view of a main part of the belt conveyance device. Here, in FIG. 7, 100 is an endless belt, 110 is a bulge of the outer peripheral surface of the endless belt 100, 120 is a rib member, 130 is a support roll, and 140 is a damaged portion.

In the belt conveyance device shown in FIG. 7, rib members 120 are provided along both edges of the inner peripheral surface of the endless belt 100 as shown in FIG. 7A, and the rib members 120 are end surfaces (guide surfaces) of the support roll 130. The endless belt 100 can be prevented from meandering.
However, this meandering prevention function is such that both the surface of the rib member 120 on the central portion side of the endless belt 100 (hereinafter sometimes referred to as “guided surface”) and the end surface of the support roll 130 are pressed. It is made to contact. For this reason, stress concentrates on the endless belt 100 located in the vicinity of the extension line of the contact surface between the guided surface of the rib member 120 and the guide surface of the support roll 130 (hereinafter, may be abbreviated as “near the contact surface”). It becomes easy to do. Further, the rib member 120 has such a force that it rides on the outer peripheral surface of the support roll 130, so that the rib member 120 is deformed to rise as indicated by reference numeral 110 on the outer peripheral surface side of the endless belt 100 in the vicinity of the contact surface.

When the endless belt 100 is run for a long time in a state where such stress concentration occurs, the endless belt 100 cannot endure the state and damage such as cracks is likely to occur in the endless belt 100 (FIG. 7B). A portion indicated by reference numeral 140 in the figure) occurs. In this case, the endless belt 100 cannot be used, and as a result, the image forming operation itself cannot be performed.
Such endless belt breakage due to stress concentration or the like is more likely to occur particularly when the mechanical strength of the endless belt itself is lowered due to long-term use.

In order to prevent the endless belt from being damaged, it has been conventionally practiced to reinforce the vicinity of a portion where the stress concentration of the endless belt is likely to occur (see, for example, Patent Document 1).
Such reinforcement is performed by sticking a tape on the outer peripheral surface or inner peripheral surface of the endless belt so as to cover a portion where stress collection is likely to occur. When such a reinforcing method is used, it is possible to suppress or prevent the endless belt from being damaged, but the endless belt reinforcing process using the tape is difficult to work and increases the cost. Since the endless belt and the tape have different coefficients of thermal expansion, problems such as sagging at the center of the endless belt may occur due to temperature changes.
JP 11-38792 A

  An object of the present invention is to solve the above problems. That is, it is an object of the present invention to provide a belt conveyance device, a belt conveyance device roll, and an image forming apparatus in which an endless belt is not damaged even when rotating for a long period of time.

The above-mentioned subject is achieved by the following present invention. That is, the present invention
<1>
An endless belt provided with rib members along both edges of the inner peripheral surface, and two or more rolls including at least a drive roll provided with guide surfaces that contact the guided surfaces of the rib members at both ends,
In the belt conveyance device in which the endless belt is stretched by the two or more rolls arranged on the inner peripheral surface thereof,
In the state where no external force is applied to the endless belt, both end portions of the endless belt are inclined in advance toward the inner peripheral surface side, and both end portions of the stretched endless belt are positioned on the inner peripheral surface side of the endless belt. inclined Tei Rukoto a belt conveying apparatus according to claim.

<2>
When the endless belt is biaxially stretched with a load of 4 kg, the angle formed by the inner peripheral surface of both ends of the endless belt and the inner peripheral surface of the endless belt central portion is 10 degrees or more <1 > Is a belt conveyance device.

<3>
The belt conveyance device according to any one of <1> and <2>, wherein a friction coefficient of the guide surface is lower than a friction coefficient of a surface of the rib member that contacts the guide surface.

<4>
<1>-<3> An image forming apparatus that includes the belt conveyance device according to any one of the above items and that forms an image according to image information on a recording medium.

  As described above, according to the present invention, it is possible to provide a belt conveyance device, a belt conveyance device roll, and an image forming apparatus in which an endless belt is not damaged even when rotating for a long period of time.

The belt conveyance device of the present invention has an endless belt provided with rib members along both edges of the inner peripheral surface, and two or more rolls including at least a drive roll provided with guide surfaces that contact the rib members at both ends. In the belt conveying apparatus in which the endless belt is stretched by the two or more rolls disposed on the inner peripheral surface thereof, both end portions of the endless belt are preliminarily connected in the state where no external force is applied. It is inclined to the peripheral surface side, and both end portions of the stretched endless belt are inclined to the inner peripheral surface side of the endless belt.

Therefore, in the belt conveying device of the present invention, both end portions of the endless belt are inclined to the inner peripheral surface side in a state where no external force is applied, and both end portions of the stretched endless belt are As described above, since the rib member is inclined toward the inner peripheral surface side, it is difficult for the rib member to ride on the outer peripheral surface of the roll provided with the guide surface, and the contact between the guided surface of the rib member and the guide surface is reduced. Stress concentration on the endless belt in the vicinity of the contact surface is alleviated, and breakage such as cracks can be prevented even if the endless belt is run for a long period of time.
In addition, the endless belt used in the belt conveyance device of the present invention does not use tape reinforcement, so it is low in cost and easy to manufacture. In addition to this, there is no problem that sagging of the central portion of the belt due to a temperature change caused by a difference in thermal expansion coefficient between the tape and the endless belt does not occur.

In the description of the present invention, the “both end portions” or “end portions” of the endless belt means the guide surfaces and ribs of the roll in the axial direction of the roll that stretches the endless belt unless otherwise specified. It means a portion of an endless belt located outside the contact surface with the guided surface of the member.
In the description of the present invention, “inner side” and “outer side” mean a positional relationship in the roll axis direction unless otherwise specified, and “inner side” is the central portion side of the endless belt, and “outer side” is It means the end side of the endless belt.

Further, in the present invention, two or more rolls are used, but at least one of these rolls needs to be a drive roll provided with guide surfaces that come into contact with the rib members at both ends. Therefore, the endless belt is prevented from meandering by at least the guide function of the guide surface of the drive roll. In addition, in order to suppress meandering more effectively, the other rolls (support rolls and the like) are also preferably rolls having a guide function in which guide surfaces that contact the rib members are provided at both ends.
In addition, the guide surface of the roll having a guide function may be constituted by both end faces of the roll body portion itself, or may be constituted by rib guide members provided at both ends of the roll body portion.

In the belt conveying device of the present invention, when the endless belt is biaxially stretched with a load of 4 kg, an angle formed between the inner peripheral surface of both ends of the endless belt and the inner peripheral surface of the endless belt central portion (hereinafter referred to as “inclination”). The angle θ1 ”may be abbreviated to 10 degrees or more, and more preferably 15 degrees or more.
When the inclination angle θ1 is less than 10 degrees, the stress concentration generated in the endless belt in the vicinity of the contact surface cannot be sufficiently relaxed, and the endless belt may be damaged when run for a long time. . From the viewpoint of preventing damage to the endless belt, it is preferable that the inclination angle θ1 is large. However, if it is too large, it may be difficult to assemble the belt conveyance device or replace the endless belt. It is preferable that it is 30 degrees or less.

  A method for calculating the inclination angle θ1 will be described with reference to the drawings. FIG. 1 is a schematic cross-sectional view for explaining a configuration example of characteristic components of the belt conveyance device of the present invention and a method for measuring the inclination angle θ1, and more specifically, stretching by a roll having a guide function. It is an enlarged view of the end part vicinity of the endless belt made. In FIG. 1, 200 is an endless belt, 200a is an end of the endless belt, 200b is a central portion of the endless belt, 201 is a rib member, 202 is a roll (or rib guide member) having a guide function, and 203 is (the rib member 201 It represents the contact surface between the guided surface and the guide surface of the roll 202.

  Θ1 represents an angle (inclination angle θ1) between the inner peripheral surface of the endless belt central portion 200b and the inner peripheral surface of the endless belt end portion 200a, and the symbol A represents the inner peripheral surface of the endless belt central portion 200b and the endless belt. A point at which the inner peripheral surface of the belt end portion 200a intersects is indicated, and a symbol A ′ is perpendicular to the inner peripheral surface (or outer peripheral surface) of the endless belt central portion 200b, passes through the point A, and is endless. A point that intersects with the outer peripheral surface of the belt 200 is indicated, X indicates an arbitrary point on the outer peripheral surface of the endless belt center portion 200b, and Y indicates an arbitrary point on the outer peripheral surface of the endless belt end portion 200a.

  Here, the inclination angle θ1 is calculated by using a CCD laser displacement sensor (manufactured by Keyence, LK-030) so that the height in the direction perpendicular to the outer peripheral surface of the endless belt central portion 200b can be measured. The distance between the belt stretched in parallel with the two axes is measured, and the step in the direction perpendicular to the outer peripheral surface of the endless belt central portion 200b between the point X and the point Y is calculated. Next, if the trigonometric function is used for this step and the value of the shortest distance from the straight line passing through the points A and A 'to the point Y, the inclination angle θ1 can be obtained.

  In measuring the inclination angle θ1, the endless belt was stretched biaxially with a load of 4 kg as shown in FIG. FIG. 2 is a schematic diagram showing a state in which an endless belt is stretched biaxially with a load of 4 kg when measuring the inclination angle θ1. In FIG. 2, 300 is an endless belt, 301 is a fixed roll, and 302 is a load. A roll that can be added, 303 is a weight suspension roll, and 304 is a weight (2 kg). The endless belt 300 is stretched biaxially by a roll having a guide function used in an actual belt conveyance device and two rolls having a guide surface at the same position in the roll axis direction. By hanging two weights 304 through the roll 303 on the other end of the two wires respectively attached, a load of 4 kg is maintained.

Note that the endless belt used in the belt conveying device of the present invention is an endless belt in which both end portions of the endless belt are inclined in advance toward the inner peripheral surface in a state where no external force is applied before being stretched on the roll (hereinafter referred to as an endless belt). , Ru Monodea using sometimes referred to as "end inclined type non end belt") (provided, however, that the the "both end portions" is the end tilt type non end belt by a roll having a guide surface to be used in combination When it is assumed that the belt is stretched, the endless belt in the outer region with respect to the contact surface between the guide surface and the guided surface is not strictly meant ).

The specific shape of the rib members such as this, and the guide surface of the rib members, in assuming a state that is in contact with the roll guide surface, is bonded to the inner peripheral surface of the endless belt of the rib member As the surface goes from the inner side to the outer side in the roll axis direction, a surface that is inclined toward the inner peripheral surface side of the endless belt can be used. Of course, the rib member having such a shape can be used even in combination with an end inclined type endless belt. The rib member may be bonded and fixed along both end edges of the inner peripheral surface of the endless belt, but may be formed as an integral part of the endless belt as part of the endless belt.

Moreover, as an end part inclination type endless belt, what was produced by the method demonstrated below can be utilized, for example.
The endless belt used in the present invention can be used as an intermediate transfer belt or the like, but this intermediate transfer belt is often made of polyimide from the viewpoint of mechanical strength. Accordingly, the end inclined type endless belt can be manufactured by using a conventional endless belt manufacturing method using polyimide resin. An endless belt using such a polyimide resin is formed by applying a polyimide precursor solution to a cylindrical or cylindrical core surface to form a polyimide precursor coating, and drying while rotating the polyimide precursor coating. And the step of heating the polyimide precursor coating film to form a polyimide resin film, and the step of peeling the polyimide resin film from the columnar or cylindrical core body or the other core body. Can do. Moreover, you may have another process as needed.
In the course of such a manufacturing process, the solvent component of the polyimide precursor solution evaporates only from the coating film surface. As a result, the amount of residual solvent differs between the front side and the back side of the coating film.If heating is performed to form a polyimide resin in this state, the end of the endless belt curls inward due to residual stress. Can be tilted. This curl amount can be adjusted by selecting the temperature and time of the drying process, the final heating process conditions, and the type of polyimide used.

As shown in FIG. 1, the belt conveyance device of the present invention is characterized in that the endless belt end portion 200 a is inclined toward the inner peripheral surface side of the endless belt 200.
Compared to the conventional belt conveyance device illustrated in FIG. 7A, in the belt conveyance device of the present invention, when the rib member comes into contact with the guide surface, the guide surface tries to ride the rib member. Since the mechanical action to be performed can be reduced, it is possible to suppress or prevent the belt from being damaged, and to suppress the end of the endless belt from traveling toward the outer peripheral surface. However, the smaller the mechanical action, the better.

In order to make this mechanical action smaller, it is necessary for the guide surface to be in a slippery state for the rib member abutting on the guide surface. Such a state can be achieved by making the friction coefficient of the guide surface lower than the friction coefficient of the surface (guided surface) in contact with the guide surface of the rib member. Adjustment of the relative relationship of the friction coefficient between such a guide surface and a guided surface can be easily achieved by selecting a material constituting each surface.
For example, when the guide surface is made of a rib guide member, urethane can be used as the rib member and POM (polyacetal) can be used in combination as the rib guide member.

The belt conveyance device of the present invention as described above can be used as a belt conveyance device of an image forming apparatus using electrophotography that forms an image according to image information on a recording medium.
Examples of the belt conveyance device used in such an image forming apparatus include an intermediate transfer belt device, a photosensitive belt device, and the like that have a toner image as a conveyance target, and a recording medium that is a conveyance target. Examples thereof include a paper conveyance transfer belt device and a normal paper conveyance belt device, and the belt conveyance device of the present invention can be used as these belt conveyance devices.

Next, a specific example of the image forming apparatus of the present invention using the belt conveying apparatus of the present invention will be described with reference to the drawings.
FIG. 3 is a schematic diagram illustrating a color image forming apparatus including a belt conveyance device according to an embodiment of the present invention. In the figure, reference numeral 10 denotes an image forming unit as an image forming apparatus capable of forming toner images of four colors of yellow (Y), magenta (M), cyan (C) and black (B), and 20 denotes an image forming unit. An intermediate transfer belt module P serving as a belt conveying device that conveys a toner image formed by the unit 10 to a predetermined position by an endless belt, P denotes a recording sheet (recording medium).

  In this color image forming apparatus, first, in the image forming unit 10, the surface of the photosensitive drum 11 as an image carrier that is rotationally driven at a predetermined speed in the direction of the arrow A is predetermined by a charging roll 12 of the charging device. The surface of the charged photosensitive drum 11 is charged uniformly, and then a laser beam Bm modulated in accordance with image information from a ROS (Raster Output Scanner) 13 as a latent image forming device is scanned and exposed to static electricity. An electrostatic latent image is formed.

Next, the electrostatic latent image is developed by the developing device 14 (Y, M, C, B) of the rotary developing device 14 in which toner corresponding to the color of the latent image is accommodated. As a result, a toner image T having a color corresponding to the electrostatic latent image is formed on the photosensitive drum 11. The toner image T formed on the photosensitive drum 11 is transferred to the outer peripheral surface of the intermediate transfer belt 21 at a primary transfer position N1 where the photosensitive drum 11 contacts the intermediate transfer belt 21.
The surface of the photosensitive drum 11 after the transfer is cleaned by a drum cleaner 15. The image information is image information obtained from a document reading device, an external connection device (such as a personal computer) or the like.

The toner image T thus formed on the photosensitive drum 11 of the image forming unit 10 is transferred to the intermediate transfer belt 21 of the intermediate transfer belt module 20.
Here, the intermediate transfer belt 21 is an endless belt made of a synthetic resin film or rubber, and a driving roll 22, a tension roll 23, a backup roll 24, and a driven roll 25 are arranged in this order on the inner peripheral surface of the intermediate transfer belt 21. It is stretched by being arranged in the clockwise direction, and is driven to rotate at a predetermined speed in the direction of arrow B. Further, a primary bias having a polarity opposite to the charged polarity of the toner on the photosensitive drum 11 is applied to the inner peripheral surface side (primary transfer position N1) of the intermediate transfer belt 21 facing the photosensitive drum 11. A transfer bias roll 26 is provided.

  In addition, a belt cleaner 27 that can contact and separate from the intermediate transfer belt 21 is disposed on the outer peripheral surface side of the intermediate transfer belt 21 that faces the driven roll 25. Further, on the outer peripheral surface side (secondary transfer position N <b> 2) facing the backup roll 24 of the intermediate transfer belt 21, a secondary transfer roll 30 that can contact and separate from the intermediate transfer belt 21 is disposed. The backup roll 24 is provided with a power supply roll 31 for applying a secondary transfer bias having the same polarity as the charging polarity of the toner on the intermediate transfer belt 21 to the roll 24.

  In such an intermediate transfer belt module 20, the toner image T on the photosensitive drum 11 is electrostatically primary transferred to the intermediate transfer belt 21 at the primary transfer position N 1, and then the intermediate transfer belt 21. Along with the rotation, the sheet is conveyed to the secondary transfer position N2. The toner image on the intermediate transfer belt 21 is secondarily transferred electrostatically to the recording paper P supplied to the secondary transfer position N2. Here, the recording paper P is stored in the paper storage cassette 35, and after being fed out of the cassette by the feed roll 36, the recording paper P is registered via a paper transport path constituted by a plurality of transport rolls 37 and the like. It is conveyed to the roll 38 and finally sent to the secondary transfer position N2 by the resist roll 38 in accordance with the secondary transfer timing. A one-dot chain line with an arrow in the figure indicates a conveyance path of the recording paper P.

  In the intermediate transfer belt module 20, when a single color image is formed, the single color toner image T primarily transferred to the intermediate transfer belt 21 is immediately secondary transferred to the recording sheet P. When a color image is formed by superimposing color toner images, the formation of each toner image on the photosensitive drum 11 and the primary transfer process of the toner image are repeated for the number of colors. It has become.

  For example, when a full color image is formed by superimposing four color toner images, yellow, magenta, cyan, and black toner images are sequentially formed on the photosensitive drum 11 and are primarily transferred to the intermediate transfer belt 21 in the order of formation. The When a color image is formed, the plurality of toner images are transferred in a superimposed manner on the intermediate transfer belt 21 as described above. Therefore, the belt cleaner 27 and the secondary transfer roll 30 are at least intermediate. The toner image previously transferred to the transfer belt 21 is brought into contact with the intermediate transfer belt 21 at a predetermined timing so as not to be disturbed when the belt cleaner 27 or the secondary transfer roll 30 touches the toner image. Alternatively, they are separated.

  Next, the recording paper P after the toner image T is secondarily transferred is sent to the fixing device 40 and subjected to a fixing process. The fixing device 40 is arranged so as to rotate in a state in which a heating roll 41 and a pressure roll (which may have a heating function) 42 are in pressure contact with each other. The recording paper P is introduced and passed through a fixing nip portion which is a pressure contact portion.

Accordingly, the recording paper P peeled off from the intermediate transfer belt 21 after the secondary transfer is sent to the fixing nip portion of the fixing device 40 and passes therethrough, so that the toner image is heated and pressurized and fixed on one side of the recording paper P. Is done. Then, after the fixing, the recording paper P is discharged from the fixing device 40 and then discharged and discharged to the outside of the apparatus or a post-processing device (or a double-sided conveyance path in the case of double-sided printing) by the discharge roll 43 or the like.
Through the above steps, the basic image forming process by the color image forming apparatus is completed.

  By the way, in this image forming apparatus, the toner image is transferred from the image forming unit 10 to the intermediate transfer belt 21 during the color image formation, or the toner image is transferred from the intermediate transfer belt 21 to the recording paper P. Since the secondary transfer is performed, if the intermediate transfer belt 21 meanders during each transfer, the multiple transfer and the secondary transfer are not normally performed, leading to a defect in image quality. For this reason, it is necessary to stably rotate the intermediate transfer belt 21 so as not to meander.

  For this reason, the intermediate transfer belt module 20 needs to have a configuration that can suppress meandering of the intermediate transfer belt 21. As a specific example of the intermediate transfer belt module 20 having such a configuration, a case where the belt conveying device of the present invention is used will be described. 4A and 4B are schematic views showing details of the intermediate transfer belt module 20 used in the image forming apparatus shown in FIG. 3, wherein FIG. 4A is a front view of the main part thereof, and FIG. 4B is a QQ line of FIG. It is principal part sectional drawing. In FIG. 4, the description of the configuration that is not related to the driving rotation of the intermediate transfer belt 21 is omitted. FIG. 5 is an enlarged view of a main part showing a contact state between the rib member of the intermediate transfer belt 21 and the rib guide member.

As shown in FIG. 4, the intermediate transfer belt 21 is stretched by four rolls 22, 23, 24, and 25, and extends along both end edges of the inner peripheral surface of the intermediate transfer belt 21 in the intermediate transfer belt module 20. A protruding rib member (protruding portion) 50 is provided.
Further, as shown in FIG. 5, among the four support rolls on which the intermediate transfer belt 21 is stretched, rolls 22 (23, 25) are provided at both ends of the drive roll 22, the tension roll 23, and the driven roll 25. A rib guide member 60 fixed to a roll shaft 22a (23a, 25a) via a bearing member 65 is provided. Here, the end portion 21 a of the intermediate transfer belt 21 is inclined toward the inner peripheral surface side of the intermediate transfer belt 21.

  As the intermediate transfer belt 21, an endless belt made of a material in which carbon black is mixed with polyimide and having a thickness of 50 to 100 μm and a width of 365 mm is used. Further, as the rib member 50, a belt-shaped member made of urethane rubber having a cross-sectional width of 5 mm and a cross-sectional height of 1 mm is attached to both ends of the inner peripheral surface of the intermediate transfer belt 21 with an adhesive or the like.

  On the other hand, as shown in FIG. 5, the rib guide member 60 is provided with rib guide members made of a structure independent of the roll body at both ends of each of the rolls 22 (23, 25). The rib guide is formed using POM (polyacetal) into a shape having a bearing hole into which the roll shaft 22a (23a, 25a) is fitted, and each rib guide is inserted through a bearing member 65 fitted into the bearing hole. The roll shaft 22a (23a, 25a) is rotatably mounted.

With such a configuration, in the intermediate transfer belt module 20, the pair of left and right rib members 50 provided at both edges of the inner peripheral surface of the intermediate transfer belt 21 are guided while being in contact with the rib guide member 60. ing. As a result, even if the intermediate transfer belt 21 attempts to meander, the meandering is suppressed by the rib member 50 being guided by the rib guide member 60. As a result, the intermediate transfer belt 21 is prevented from meandering. Rotates in a stable state.
In the configuration shown in FIG. 5, both end portions 21 a of the intermediate transfer belt 21 are formed so as to be slightly inclined toward the inner peripheral surface side of the intermediate transfer belt 21. This makes it difficult to ride on the rib guide member 60 when the rib member 50 enters the rib guide.

  As a result of the difficulty of the climbing, the deformation of the intermediate transfer belt 21 in the vicinity of the contact surface between the rib member 50 and the rib guide member 60 that causes breakage such as a crack is suppressed, so that the durability of the intermediate transfer belt 21 is improved. improves. For this reason, even when the intermediate transfer belt 21 is rotated for a long period of time, troubles such as the necessity of stopping the image forming operation due to the belt breakage are less likely to occur.

Furthermore, in the embodiment shown in FIG. 5, the rib member 50 (the guided surface 50a) is a rubber surface, whereas the rib guide member 60 (the guide surface 61) is the surface of a plastic molded product. The surface of the member 60 has a smaller friction coefficient than the surface of the rib guide member 60. For this reason, since the guide part 60 becomes slippery with respect to the rib member 50, when the rib member 50 abuts against the guide part 60, a mechanical action for trying to ride the rib member 50 by contact frictional force is exerted. Weaken. As a result, the climbing amount of the rib member 50 can be further suppressed.
By satisfying the friction coefficient relationship between the guide surface 61 of the rib guide member 60 and the guided surface 50a of the rib member 50, the deformation as described above is further suppressed, so that damage such as a crack is less likely to occur. Therefore, the durability of the intermediate transfer belt 21 is further improved.

In the embodiment shown in FIG. 5, the intermediate transfer belt module 20 is manufactured by using the intermediate transfer belt 21 having a different inclination angle θ1 when biaxially stretched in a state where a load of 4 kg is applied. FIG. 6 shows the result of evaluating the amount of climb α (mm) of the belt 21. In FIG. 6, the horizontal axis represents the inclination angle θ1 and means the intermediate transfer belt 21 having a conventional configuration (no inclination at both ends) only for θ1 = 0 degrees, and the vertical axis represents the amount of climb α (mm). means.
As can be seen from FIG. 6, the running amount α decreases as the inclination angle θ1 increases, and the intermediate transfer belt 21 in the vicinity of the contact portion between the guide surface and the guided surface increases as the inclination of both ends increases. It can be seen that deformation is less likely to occur.
The ride amount α is the difference between the height of the A ′ portion in FIG. 1 in the stationary state when the belt is stretched and the height of the A ′ portion in the driving state, and a dial gauge is set in the A ′ portion in FIG. It can be obtained by measuring the difference in height between the stationary state and the driving state.

  When the intermediate transfer belt module 20 having the configuration described above with reference to FIG. 5 is used, the intermediate transfer belt 21 is not damaged by belt deformation due to belt deformation caused by the rib member 50 riding on the rib guide member 60. There is no occurrence, and it can run stably for a long time. In addition, since the intermediate transfer belt 21 is not easily damaged, it can be stably rotated, and the primary transfer and the secondary transfer are performed well without any problems such as misalignment, and the intermediate transfer belt 21 is damaged. A good color image can be stably formed without causing trouble.

In the embodiment illustrated in FIG. 5, the rib member 50 is bonded and fixed along both edges of the inner peripheral surface of the intermediate transfer belt 21, but the rib member 50 and the intermediate transfer belt 21 are connected to the belt. It may be formed integrally in the production.
The intermediate transfer belt device has been exemplified as the belt conveying device. However, a photosensitive belt device including a belt-like image carrier such as a photosensitive belt that forms and carries a toner image, or a recording paper is carried and transferred. The present invention can also be applied to a sheet conveyance transfer belt apparatus including a sheet conveyance transfer belt that conveys a position and the like, and the same effects as those of the intermediate transfer belt apparatus described above can be obtained. Furthermore, the belt conveying apparatus having such a configuration can be applied as a belt conveying apparatus used in addition to the image forming apparatus.

  Further, as the image forming apparatus, the image forming apparatuses 10 are used for the colors of the toner images constituting the color image by each image forming apparatus 10 (in this case, the developing device in each image forming apparatus). Only one developing unit that accommodates the toner of each color), and the so-called tandem type in which the toner images of the respective colors are separately formed by the respective image forming devices and sequentially transferred onto the intermediate transfer belt 21. The image forming apparatus may be used.

Example 1
In the embodiment shown in FIG. 5, a polyimide endless belt having an inclination angle θ1 of 10 ° when biaxially stretched under a load of 4 kg is used, and the rib member is made of urethane and has a width of 5 mm and a thickness of 1 mm. The material was bonded to the inner surface of the endless belt using an adhesive.
Using this endless belt, an intermediate transfer belt module was manufactured, and an endless belt driving speed was set to 205 mm / second, and a continuous driving test was performed for 80 hours.
The amount α (mm) of the intermediate transfer belt climbed at this time was measured and found to be 0.2 mm. Further, the endless belt did not break even after 80 hours from the start of driving, and did not break even after being driven for 120 hours (200 hours in total).

(Example 2)
In the embodiment shown in FIG. 5, an endless belt made of polyimide having an inclination angle θ1 of 5 ° when biaxially stretched under a load of 4 kg is used, and the rib member is made of urethane and has a width of 5 mm and a thickness of 1 mm. These were bonded to the inner surface of the endless belt using an adhesive.
Using this endless belt, an intermediate transfer belt module was manufactured, and an endless belt driving speed was set to 205 mm / second, and a continuous driving test was performed for 80 hours.
When the amount α (mm) of the intermediate transfer belt climbed at this time was measured, it was 0.5 mm. The endless belt was not broken even after 80 hours from the start of driving.

(Comparative Example 1)
In the embodiment shown in FIG. 5, an endless belt made of polyimide having an inclination angle θ1 of 0 ° when biaxially stretched under a load of 4 kg is used, and the rib member is made of urethane with a width of 5 mm and a thickness of 1 mm. These were bonded to the inner surface of the endless belt using an adhesive.
Using this endless belt, an intermediate transfer belt module was manufactured, and an endless belt driving speed was set to 205 mm / second, and a continuous driving test was performed for 80 hours.
When the amount α (mm) of the intermediate transfer belt climbed at this time was measured, it was 0.6 mm. Further, 60 hours after the start of driving, a crack of about 5 mm occurred in the endless belt near the contact surface between the rib member and the rib guide portion. Further, when the driving was continued for 1 hour as it was, this crack was greatly spread and the endless belt was broken, and it became impossible to run.

FIG. 6 is a schematic cross-sectional view for explaining a configuration example of characteristic components of the belt conveyance device of the present invention and a method for measuring the inclination angle θ1. It is a schematic diagram which shows the state which extended the endless belt biaxially with the load of 4 kg in the case of measurement of inclination | tilt angle (theta) 1. 1 is a schematic diagram illustrating a color image forming apparatus including a belt conveyance device according to an embodiment of the present invention. 4A and 4B are schematic views showing details of an intermediate transfer belt module 20 used in the image forming apparatus shown in FIG. 3, wherein FIG. 5A is a front view of the main part thereof, and FIG. It is. 3 is an enlarged view of a main part showing a contact state between a rib member and a rib guide member of the intermediate transfer belt 21. FIG. It is a graph which shows the relationship of climbing amount (alpha) with respect to inclination-angle (theta) 1. FIG. 7A is a schematic view showing an example of a conventional belt conveyance device using an endless belt provided with rib members along both edges of the inner peripheral surface, and FIG. 7A is a support roll of the belt conveyance device and stretched. It is a schematic cross section shown about the cross-section part of an endless belt, FIG.7 (b) is a principal part perspective view of a belt conveying apparatus.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Image forming device 11 Photosensitive drum 12 Charging roll 13 ROS
14 Rotary Development Devices 14Y, 14M, 14C, 14B Developer 15 Drum Cleaner 20 Intermediate Transfer Belt Module 21 Intermediate Transfer Belt 21a Intermediate Transfer Belt End 22 Drive Roll 22a Roll Shaft 23 Tension Roll 23a Roll Shaft 24 Backup Roll 25 Followed Roll 25a Roll shaft 26 Primary transfer bias roll 27 Belt cleaner 30 Secondary transfer roll 31 Power supply roll 35 Paper storage cassette 36 Feed roll 37 Transport roll 38 Registration roll 40 Fixing device 41 Heating roll 42 Pressure roll 43 Discharge roll 50 Rib Member 50a Guided surface 60 Rib guide member 61 Guide surface 65 Bearing member T Toner image P Recording paper 100 Endless belt 110 Rise of outer peripheral surface of endless belt 100 Rib member 130 Support b Roll having a central portion 201 rib members 202 guide function of the end portion 200b endless belt Le 140 damaged portion 200 endless belt 200a endless belt (or rib guide member)
203 Contact surface 210 Belt conveyor 300 Endless belt 301 Fixed roll 302 Roll 303 capable of applying load 303 Weight suspension roll 304 Weight (2 kg)

Claims (4)

An endless belt provided with rib members along both edges of the inner peripheral surface, and two or more rolls including at least a drive roll provided with guide surfaces that contact the guided surfaces of the rib members at both ends,
In the belt conveyance device in which the endless belt is stretched by the two or more rolls arranged on the inner peripheral surface thereof,
In the state where no external force is applied to the endless belt, both end portions of the endless belt are inclined in advance toward the inner peripheral surface side, and both end portions of the stretched endless belt are positioned on the inner peripheral surface side of the endless belt. inclined belt conveyor device according to claim Tei Rukoto.   The angle between the inner peripheral surface of both ends of the endless belt and the inner peripheral surface of the central portion of the endless belt when the endless belt is biaxially stretched with a load of 4 kg is 10 degrees or more. The belt conveyance device according to 1.   The belt conveyance device according to claim 1, wherein a friction coefficient of the guide surface is lower than a friction coefficient of a surface of the rib member that abuts on the guide surface.   An image forming apparatus comprising the belt conveyance device according to claim 1, and forming an image according to image information on a recording medium.

Images