JP2002326733A - Belt conveyor device and image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the production of rib rubbing chips by preventing the rib of a belt from rubbing a drive or driven roller in simple structure. SOLUTION: The rib 37a is provided in an edge section of the transfer belt 37 in the width direction on the side of the back face of the belt 37 along the running direction, and a collar member 72 with a cutout section 72b having a shape with which the rib 37a of the transfer belt 37 engages, is arranged in the end section of the drive roller 38 in its rotary axial direction so as to be rotatable in relation to the drive roller 38.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a belt conveying device for endlessly moving a belt member such as a transfer paper conveying belt or an image carrier belt used in an image forming apparatus such as a printer, a facsimile, and a copier.

[0002]

2. Description of the Related Art Conventionally, in a color image forming apparatus provided with image forming units for four colors of cyan, magenta, yellow and black, transfer images are transferred to transfer sheets in each image forming unit. The image forming apparatus includes a belt conveying device that allows a long belt to be conveyed to the image forming unit to run endlessly. This belt is stretched around a plurality of rollers including a driving roller and a driven roller, and runs endlessly by rotation of the driving roller. Then, in order to prevent meandering during belt running, a rib or the like is provided along the running direction at the width direction end on the back side of the belt, and a cutout having a shape corresponding to the rib is formed on the driving roller and the driven roller. There has been proposed a belt transport device that has a configuration in which the belt is run in a state in which a rib is fitted in the notch.

[0003]

However, in the above belt conveying device, when the belt approaches the arc portion of the driving roller or the driven roller during belt running, the ribs of the belt are compressed and shrinkage occurs. When the belt separates from the arc portion of the driving roller or driven roller and returns to a straight line, the rib is released from compression and extends, so the moving speed of the inner surface and end surface of the rib changes, and the rib rubs against the driving roller or driven roller. I can't avoid the situation of being cut off. If the shavings of the ribs are generated, they adhere to the drive roller, driven roller, transfer roller, etc., causing problems such as poor transfer, reduced belt cleaning performance, and reduced meandering prevention effect. (So-called deterioration of the color resist) and cause contamination in the image forming apparatus.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and has a simple structure to eliminate friction between a rib of a belt and a driving roller or a driven roller, thereby reducing generation of shavings on the rib. It is an object of the present invention to provide a belt conveyance device and an image forming apparatus capable of preventing the belt conveyance.

[0005]

According to a first aspect of the present invention, there is provided an image forming apparatus, comprising: a plurality of rollers including at least a driving roller and a driven roller; And a belt that runs endlessly with the belt, and wherein a rib along the running direction is provided at a widthwise end on the back side of the belt, wherein a shaft of at least one of the plurality of rollers is provided. A collar member having a cutout portion that fits with a rib of the belt is rotatably attached to the roller at the end in the direction.

According to this structure, the belt runs while the ribs are fitted into the notches of the collar member, so that movement of the belt in the width direction is restricted, and meandering of the belt is prevented. Even when the belt moves toward the arc of the driving roller or the driven roller and the moving speed of the rib portion changes, the color member rotates independently of the roller according to the changing speed of the rib. Is absorbed, and rubbing between the rib and the collar member is prevented. The effect of the attachment of the collar member can be obtained by attaching the belt member to all the rollers around which the belt member is stretched, or attaching it to only one of the rollers.

[0007] The invention described in claim 2 is the first invention.
The diameter of the collar member is smaller than the diameter of the roller.

According to this configuration, even when the belt approaches the arc of the driving roller or the driven roller and the rib portion is compressed and bent inward of the roller, the bending of the rib is absorbed, and the rib and the collar member are connected to each other. Is prevented from rubbing.

[0009] The invention described in claim 3 is the first invention.
Alternatively, in the belt conveying device according to claim 2, the collar member is attached to the end of the roller so as not to contact a painted portion on the surface of the roller.

According to this structure, even when the color member rotates at a different speed from the roller and rubs against the roller, the coating on the roller surface does not come off due to the rubbing.

The invention described in claim 4 is the first invention.
4. The belt conveying device according to claim 3, wherein the cutout portion of the collar member is formed so as to fit in a non-contact state with a rib of the belt.

According to this structure, when the belt reaches the arc of the driving roller or the driven roller and the rib portion is compressed and bent inward of the roller, the bent portion is absorbed by the notch of the collar member. In addition, the rubbing between the rib and the collar member is more reliably prevented.

The invention described in claim 5 is the first invention.
5. The belt conveying device according to claim 4, wherein the collar member is made of a synthetic resin.

According to this structure, since the insulating property of the color member is enhanced, even when the belt is brought into contact with the photosensitive drum and the transfer roller to transfer the electric charge to the belt, the driving roller and the like are used. Can be prevented from leaking to the unit housing that supports.

According to a sixth aspect of the present invention, there is provided a belt transport apparatus according to any one of the first to fifth aspects, wherein the belt member of the transfer paper transport belt or the image carrier belt is run endlessly. An image forming apparatus comprising:

[0016]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a developing device and an image forming apparatus according to one embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a schematic configuration diagram of a color printer as an example of an image forming apparatus according to the present invention.

A schematic configuration of a color printer 1 to which the present invention is applied will be described with reference to FIG. A color printer 1 feeds a sheet member 3 as a transfer body one sheet at a time.
A conveying unit 6 for conveying the sheet member 3 sent from the sheet feeding unit 4; an image forming unit 5 for forming a toner image to be transferred to the sheet member 3; and a toner image formed by the image forming unit 5 , A fixing unit 8 for fixing the toner image of the sheet member 3 transferred by the transfer unit 7, and a sheet discharging unit 10 for receiving the sheet member 3 discharged from the fixing unit 8. And an optical unit 11 for forming an electrostatic latent image on the photosensitive drum 28 by a laser beam.

The paper feed unit 4 includes a first paper feed unit 15 that feeds the sheet members 3 stacked on the first paper feed tray 12 to the downstream side one by one with a paper feed roller 13 and a retard roller 14.
And a second paper feed unit 18 that feeds the sheet members 3 from the manual feed tray 16 to the downstream side one by one by a paper feed roller 17.

The transport section 6 includes a transport path 20 for guiding the transport of the sheet member 3 sent from the first paper feed section 15, a transport roller 21 disposed in the middle of the transport path 20, and a transport roller 21. A registration roller pair 22 for receiving the sheet member 3 from the printer, temporarily stopping the leading end of the sheet member 3, restricting (correcting) the oblique feeding, and feeding the image to the image forming unit 5 on the downstream side;
The manual feed path 23 communicates with the second paper feed unit 18.

The image forming section 5 includes a first image forming section 24 having black toner, a second image forming section 25 having cyan toner, a third image forming section 26 having magenta toner, and a fourth image forming section having yellow toner. And a unit 27. The first to fourth image forming units 24, 25, 26, and 27 have a cylindrical photosensitive drum 28 and a charging device that applies a charge to the photosensitive drum 28 to uniformly charge the surface of the photosensitive drum 28. 29
And a developing device 30 that supplies a developer to the electrostatic latent image on the surface of the photosensitive drum 28 to form a toner image, and a fur brush 31 and a cleaning blade 32 that remove residual toner on the photosensitive drum 28. And a cleaning device 33 provided therein.

The transfer section 7 includes an endless transfer belt 37 made of a fluorine resin material, a drive roller 38 for driving the transfer belt 37, and a tension roller (follower roller) 40.
And a belt conveying device having transfer rollers 41a, 41b, 41c, and 41d arranged at positions facing the respective photosensitive drums 28. In addition to an image transfer function to the sheet member 3, the sheet member 3 is moved downstream. It also has the function of transporting to The transfer belt 37 includes transfer rollers 41a and 4
1b, 41c, 41d and each photosensitive drum 28. Guide rollers 42 and 43 are provided at appropriate positions on the inner peripheral side of the transfer belt 37. When forming only a black-and-white image, the transfer unit 7 uses only the black transfer roller 41a, and the other magenta, cyan, and yellow transfer rollers 41b, 41c, and 41d are separated from the photosensitive drum 28. .

The fixing section 8 is pressed against the heating roller 44 having a built-in heater, the fixing roller 45, a metal endless belt 46 wound around the heating roller 44 and the fixing roller 45, and the fixing roller 45. Pressure roller 4
7 are provided. And an oil application roller 48 for applying silicon oil to the outer surface of the endless belt 46;
An oil supply roller 50 that supplies oil to the oil application roller 48 and a cleaning roller 51 that cleans the surface of the oil supply roller 50 are provided.

The paper discharging unit 10 receives the sheet member 3 discharged from the fixing unit 8 and discharges the sheet member 3 with the image forming surface up, and a fixing unit 8 (shown by a virtual line in FIG. 1). Part 8
The sheet member 3 discharged from the printer is guided to an upper portion of the apparatus main body 36 by a discharge path 53, and has a second paper discharge portion 54 that is discharged with the image forming surface down. The first paper discharge unit 52 is stored in the apparatus main body 36 when not in use.

The optical unit 11 includes a polygon mirror 5
5, lenses 56 and 57 and a mirror 58 are provided corresponding to each of the photosensitive drums 28, and direct laser light from the slits 61 formed in the optical unit support plate 60 toward each of the photosensitive drums 28. Irradiation.

In the color printer 1 having the above configuration, when the sheet member 3 is sent out from the first sheet supply unit 15 or the second sheet supply unit 18, the sheet member 3 is transported by the transport unit 6 to the first image forming unit 24. Is transferred between the photosensitive drum 28 and the transfer belt 37. The sheet member 3 is provided with a transfer roller 41 corresponding to the photosensitive drum 28 of each color.
a, 41 b, 41 c, 41 d
Black, cyan, magenta, and yellow photosensitive drums 28
, The toner images are sequentially transferred to the sheet member 3. The sheet member 3 on which the toner images of the respective colors are superimposed and the transfer of the color image has been completed is fed between the fixing roller 45 and the pressure roller 47 of the fixing unit 8, where the color image is fixed. After the fixing, the sheet member 3 is discharged to the first paper discharge unit 52 or the second paper discharge unit 54.

The transfer belt 37 and the drive roller 38 of the above-described belt transport device will be described. FIG. 2 shows the transfer belt 3
FIG. 3 is a side view showing a portion of the drive roller
FIG. 3 is a sectional view taken along line AA of FIG. 2. FIG. 3 shows a unit housing for clarifying the support structure of the drive roller 38.

The drive roller 38 is made of aluminum or the like, and has a surface provided with a urethane coating film 38a. By the urethane coating film 38a on the surface of the drive roller 38, the frictional resistance between the transfer belt 37 and the drive roller 38 is increased to improve the running stability of the transfer belt 37 and to transfer the image from the photosensitive drum 28 when transferring the image. Insulation (10E + 8
Ωcm or more). Urethane coating film 3
Reference numeral 8a is provided on the contact surface of the drive roller 38 with the transfer belt 37, and is also provided on a part of the side end surface of the drive roller 38 to further enhance the adhesive stability. The rotation shaft 39 of the drive roller 38 is rotatably supported by a bearing 71 provided in a unit housing 70 of the transfer unit 7.

The transfer belt 37 is made of PVDF (polyvinylidene fluoride), CR rubber, urethane rubber, or the like.
It is stretched between the driving roller 38 and the tension roller 40. The transfer belt 37 runs in synchronization with the rotation of each of the photosensitive drums 28 by the rotation of the drive roller 38. A rib 37a is provided at an end in the width direction on the back surface side of the transfer belt 37 along the belt running direction. The rib 37a has a shape protruding from the transfer belt 37 as shown in FIG.
b, it is attached to the transfer belt 37. The transfer belt 37 has a width direction end region having a rib 37a,
The roller body 38 in the rotation axis direction of the drive roller 38
It is stretched around the drive roller 38 so as to protrude from b.

A collar member 72 is attached to the rotating shaft 39 between the roller body 38a and the unit housing 70. The collar member 72 is made of a synthetic resin such as polyacetal or polycarbonate, and has a donut shape having an opening 72a through which the rotation shaft 39 passes at a substantially central portion. The diameter of the collar member 72 is set smaller than the diameter of the drive roller 37. The width of the collar member 72 in the rotation axis direction of the drive roller 38 is slightly smaller than the distance from the inner wall of the unit housing 71 to the roller body 38b so that the collar member 72 can rotate independently of the drive roller 38. It has small dimensions. The diameter of the opening 72 a is slightly larger than that of the rotating shaft 39 so that the collar member 72 rotates independently of the rotating shaft 39. With such a configuration, the collar member 72 is rotatable with respect to the drive roller 38.

The outer peripheral portion of the collar member 72 facing the rib 37a of the transfer belt 37 is provided with a rib 37
A notch 72b having a shape corresponding to a is formed, but the sizes of the notch 72b and the rib 37a are set so as not to contact with each other. Notch 7
A protrusion 72c is formed on the outer peripheral portion of the collar member 72 on the side of 2b.
By locking the side of the rib 37a to the protrusion 72c, the movement of the transfer belt 37 in the width direction is restricted, and the meandering of the transfer belt 37 is prevented.

In the collar member 72, the roller body 3
The side surface portion 72d facing 8b is formed so as to have a fixed distance from the roller body portion 38b so as not to contact the roller body portion 38b. The roller body 38
At the side end of b, the urethane coating film 38a is not provided in a portion that comes into contact with the collar member 72, and the collar member 72 and the urethane coating film 38a are kept in a non-contact state at all times. .

The drive roller 38 has a urethane coating film 38a at both ends in the rotation axis direction in the same manner as above.
And a collar member 72, and the tension roller 40 has the same configuration.

The belt running operation of the transfer belt 37, drive roller 38 and tension roller 40 having the above configuration will be described. When the driving roller 38 is driven to rotate, the urethane coating film 38 on the surface of the driving roller 38
The transfer belt 37 is conveyed by the friction between the transfer belt 37 and the transfer belt 37. Accordingly, the tension roller 40 also rotates. When the belt runs, the transfer belt 37 is driven by a driving roller 38.
Alternatively, when the transfer belt 37 reaches the tension roller 40, the transfer belt 37 travels along the circular arc shape of the outer periphery of the drive roller 38 or the tension roller 40. Bend. At this time, the rib 37a moves toward the roller center (approaches the collar member 72), but the diameter of the collar member 72 is set smaller than the diameter of the roller main body 38b. Since the portion 72b is formed, the movement of the rib 37a is notched.
b. Even when the amount of deflection of the rib 37a is large and the rib 37a comes into contact with the notch 72b, the collar member 72 rotates independently of the drive roller 38 or the tension roller 40, so that the rib 37a
Even if the running speed of the rib 37a of the transfer belt 37 changes due to the deflection of the
2 rotates, the rib 37a and the collar member 72 are rotated.
And no rubbing occurs between them.

Further, since the movement of the transfer belt 37 in the width direction is restricted by the protrusion 72c of the collar member 72 being engaged with the rib 37a of the transfer belt 37, the transfer belt 37 is prevented from meandering. Further, the roller body 38
The urethane coating film 38a is not provided on the contact portion between the color member 72 and the color member 72.
2 has an interval from the portion where the urethane coating film 38a at the end of the roller body 38b is provided, so that even when the collar member 72 is separately rotated independently of the drive roller 38 or the tension roller 40, The urethane coating film 38a does not peel off due to the rubbing of both members.

The present invention is not limited to the configuration of the above-described embodiment, but can be variously modified. For example, in the above embodiment, the diameter of the collar member 72 is smaller than the diameter of the roller body 38b, but the diameter of the collar member 72 may be substantially the same as the diameter of the roller body 38b. Good. Further, in the above embodiment, the collar member 72 is not in contact with the urethane coating film 38a of the roller main body 38b, but may be configured so that the collar member 72 is in contact with the urethane coating film 38a. Even in these cases, the effect of avoiding the rubbing between the rib 37a and the collar member 72 can be obtained.

In the above embodiment, the transfer belt 37
The rib 37a and the notch 72b of the collar member 72 are not in contact with each other, but the rib 37a and the notch 72b
However, as long as the collar member 72 rotates separately and independently of the drive roller 38 or the tension roller 40, the sliding of the rib 37a and the collar member 72 can be prevented. In the above embodiment, the color member 7
2 is made of a synthetic resin such as polyacetal or polycarbonate, but it is also possible to apply a material made of a material other than these.

Further, in the above-described embodiment, an example is shown in which the belt transport device according to the present invention is applied to the transfer belt 37 for transporting the transfer paper, but an image carrier such as a belt-shaped photoreceptor or an intermediate transfer belt. It is also possible to apply the belt transport device for running the belt endlessly.

In the above-described embodiment, an example is shown in which the belt conveying device is applied to a color printer. However, the present belt conveying device is also applied to an image forming apparatus such as a tandem recording type color copier or a facsimile. The present invention can be applied to a monochrome printing image forming apparatus as long as the transfer sheet is transported by a belt.

In the above embodiment, the collar member 72
Is attached to the drive roller 38 and the tension roller 40, but may be attached to all the rollers (the transfer rollers 41a to 41d, the guide rollers 42, 43, etc.) around which the transfer belt 37 is stretched. May be attached to only one of the rollers.

[0040]

As described above, according to the present invention, the movement of the belt in the width direction is restricted by fitting the rib of the belt and the notch of the collar member, thereby preventing the belt from meandering. In addition, even if the belt moves toward the arc of the driving roller or the driven roller, causing a change in the moving speed of the rib portion, the collar member is rotated independently from the roller in accordance with the change in the moving speed of the rib portion. By doing so, there is an effect that rubbing between the rib portion and the collar member is prevented. This makes it possible to prevent the generation of shavings in the rib portion with a simple structure, and to improve the transfer failure and the belt cleaning performance caused by the shavings of the ribs adhering to the driving roller, the driven roller, the transfer roller, or the like. It is possible to eliminate the adverse effects such as the reduction and the meandering prevention effect, further prevent the contamination in the image forming apparatus, and improve the performance stability. In particular, when the present belt conveyance device is used in a tandem recording type color image forming apparatus, good image formation can be achieved without causing misregistration of images of respective colors (without deteriorating the so-called color registration). It can be carried out.

In the case where the diameter of the collar member is smaller than the diameter of the roller, even if the belt approaches the arc of the driving roller or the driven roller and the rib portion is compressed and bent inward of the roller, the rib may be bent. Is absorbed, and sliding friction between the rib and the collar member is prevented.

If the color member is attached to the end of the roller so as not to contact the painted portion on the surface of the roller, even if the color member rotates at a different speed from the roller and rubs against the roller. The coating on the roller surface does not come off due to this rubbing.

In the case where the cutout portion of the collar member is formed so as to be fitted in a non-contact state with the rib of the belt, the belt comes into contact with the arc of the driving roller or the driven roller, and the rib portion is compressed and the roller portion is compressed. When bent inward, the amount of this bending is absorbed by the notch of the collar member,
Rubbing between the rib and the collar member is more reliably prevented.

Further, when the collar member is made of a synthetic resin, the insulation of the collar member is enhanced, so that
Even in the case where the belt is in contact with the photosensitive drum and the transfer roller and the like and the charge is transmitted to the belt, it is possible to prevent the charge from leaking to the unit housing that supports the driving roller and the like.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram of a color printer as an example of an image forming apparatus according to the present invention.

FIG. 2 is a side view showing a driving roller portion on which a transfer belt is stretched.

FIG. 3 is a sectional view taken along line AA of FIG. 2;

[Explanation of symbols]

 Reference Signs List 1 color printer (image forming apparatus) 38 drive roller 37 transfer belt 37a rib 38a urethane coating film 40 tension roller 72 color member 72b notch

Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat II (reference) G03G 15/00 518 G03G 15/00 518 3F049 15/16 15/16 21/00 350 21/00 350 F term (reference) 2H035 CA05 CB06 CF02 CG03 2H072 CA05 CB07 JA03 JC02 2H200 FA04 FA08 FA09 GA12 GA23 GA24 GA34 GA44 GA47 GA49 HA02 HB12 HB22 JA02 JB06 JB20 LA06 LA23 LA29 3F024 AA03 BA04 BA05 CA02 CA04 CB03 DA03 GA03 AGO3 GC03 DA03 LA02 LA05 LA07 LB03

Claims (6)

[Claims] 1. A vehicle comprising: a plurality of rollers including at least a driving roller and a driven roller; and a belt stretched over the rollers and running endlessly with rotation of the driving roller.
In a belt conveying device provided with a rib extending in a running direction at a width direction end of a belt rear surface side, an axial end of at least one of the plurality of rollers is fitted with a rib of the belt. A belt conveying device, wherein a collar member having a cut-out portion is rotatably attached to a roller. 2. The belt conveying device according to claim 1, wherein a diameter of the collar member is smaller than a diameter of the roller. 3. The belt conveying device according to claim 1, wherein the collar member is attached to an end of the roller so as not to contact a painted portion on the surface of the roller. 4. The belt according to claim 1, wherein the cutout portion of the collar member is formed so as to fit in a non-contact state with a rib of the belt. Belt transport device. 5. The belt conveying device according to claim 1, wherein the collar member is made of a synthetic resin. 6. An image forming apparatus comprising the belt transport device according to claim 1 for endlessly running a belt member of a transfer paper transport belt or an image carrier belt. apparatus.