JPH05193718A - Belt conveyer device - Google Patents

Abstract

PURPOSE:To realize a rotary roller expanded in the central part or both ends with a simple structure by attaching two conical tapered members onto a rotary shaft so that the inclining directions of the outer peripheral surfaces are opposite to each other. CONSTITUTION:Two tapered members 28 having one end expanded compared with the other end to form the outer conical peripheral surface respectively are attached to a rotary shaft 29 so that the inclining directions of the outer peripheral surfaces are opposite to each other. Further, key ways 31, 32 are formed respectively in the inner peripheral surface of a shaft hole 30 of the tapered member 28 and the outer peripheral surface of the rotary shaft 29. While a key 33 is engaged with these key ways 31, 32, two tapered members 28 slidably fitted on the rotary shaft 29 are fixed by a stopper 34. A crown roller having the central portion expanded and a inverted crown roller having both ends expanded can be formed by changing the direction of these tapered members 28.

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 used for a sheet conveying mechanism of an electrophotographic apparatus.

[0002]

2. Description of the Related Art In recent years, electrophotography has been developed as one of electrostatic image forming methods. In this method, an electrostatic latent image is formed on a photoconductor, which is a charged latent image carrier, by optical scanning or the like, and the electrostatic latent image is developed with charged toner and transferred to a recording paper. A belt conveying device using this electrophotographic method is provided with a printing station in which at least a charging device, an exposing device, and a developing device are arranged to face each other on the outer peripheral surface of a latent image carrier such as a photosensitive belt. The structure is such that it is arranged to face the paper transport mechanism. here,
A roller transport device, a belt transport device, and the like are used for such a sheet transport mechanism. However, a belt transport device that electrostatically adsorbs printing paper and precisely transports it is composed of a plurality of rotatably supported shafts. It has a structure in which an endless belt is rotatably stretched around a rotating roller.

Therefore, a color printer disclosed in Japanese Patent Laid-Open No. 63-301084 will be described as a conventional example of such a belt conveying device with reference to FIG. First, in this color printer 1, a drum charger (not shown) and a laser scanner 3 are provided on the outer peripheral surface of the photosensitive drum 2 which is rotatably supported.
And developing device of three with a (not shown) are sequentially arranged opposite the printing station ₄₁ to ₃ provided, these printing stations ₄₁ to ₃ of the photosensitive drum 2 on the endless belt 6 of the belt conveyor device 5 It has a structure that is arranged to face. In the belt conveying device 5, the endless belt 6 is stretched around two rotatable rollers 7 and 8 that are rotatably supported. One of the rotatable rollers 7 and 8 is a normal cylinder. Although it is a shape, the other is a crown roller in which the central portion is expanded to have a larger diameter than both end portions.

[0004] In this structure, if in the color printer 1 to print the color image, in the respective printing station ₄₁ to _3, the laser scanner on the outer peripheral surface of the photosensitive drum 2 charged by the charge applied in the drum charger An electrostatic latent image is formed by the optical scanning of 3, and the electrostatic latent image is developed into one single-color image of three primary colors by the color toner supplied from the developing device. When the printing paper 9 on the endless belt 6 which roll in synchronism with the operation of the printing station ₄₁ to ₃ is fed, the printing paper 9 is electrostatically adsorbed on the endless belt 6 because it carried by state, so that the color image is formed by three primary colors of monochromatic images from the photosensitive drum 2 of each printing station ₄₁ to ₃ on the surface of the printing paper 9 is sequentially overprint.

In the above-described belt conveying device 5, one of the two rotating rollers 7 and 8 is used as a crown roller to prevent the rolling of the rolling endless belt 6 in the axial direction, thereby preventing the color printer 1 from being displaced. It contributes to the improvement of print quality.

[0006]

In the belt transfer device 5 of the color printer 1 described above, the two rotary rollers 7 and 8 are used.
By using one of them as a crown roller, displacement of the rolling endless belt 6 in the axial direction is prevented.

However, the rotary roller 8 whose central portion is widened as compared with the both end portions is formed by, for example, cutting a cylindrical base material, and is formed exactly symmetrically. It is difficult to do so, and productivity is decreasing.

As the rotating roller for preventing the displacement of the rolling endless belt as described above, there is an anti-crown roller whose both end portions are widened compared to the central portion.
This also reduces productivity because it is difficult to accurately form a cylindrical base material symmetrically.

[0009] The present invention is to obtain a belt conveyor having good productivity.

[0010]

In a belt conveying device in which an endless belt is rotatably stretched by a plurality of rotating rollers rotatably supported, the other end of the belt conveying device is widened as compared with one end. At least one of the rotating rollers is formed by providing a taper member having a conical outer peripheral surface and mounting the two taper members on a rotating shaft so that the inclination directions of the outer peripheral surfaces are opposite to each other.

[0011]

[Function] Since the rotating roller having the shape in which the central portion and the both ends are widened can be realized by combining one kind of taper member, it is easy to accurately make the shape symmetrical and the productivity is improved. Therefore, it is possible to obtain a belt conveying device having good productivity.

[0012]

Embodiments of the present invention will be described with reference to FIGS. First, as illustrated in FIG. 3, the belt carrying device 10 of the present embodiment is also used for the paper carrying mechanism of the color printer 11. Therefore, in the color printer 11, the drum cleaner 13, the drum charger 14, the laser scanner 15, and the laser scanner 15 are provided on the outer peripheral surface of the rotatable photosensitive drum 12.
There are provided _four printing stations 17 _{1 to} 174 in which developing devices 16 respectively storing yellow, magenta, cyan, and black color toners (not shown) are sequentially opposed to each other, and these printing stations 17 ₁ are provided. The photosensitive drums 12 to 17 ₄ are arranged to face each other on the endless belt 18 of the belt conveying device 10.

Here, at a conveyance start position at one end of the endless belt 18 in the stretching direction, a paper holding roller 19 is rotatably supported on the upper surface, and a paper feeding device 20 is provided at a position communicating with the upper surface. Are arranged in close proximity to each other, and the endless belt 1 is provided behind the sheet holding roller 19 in the conveying direction.
A transfer charging device 21 is arranged at a position opposed to 8. Further, a fixing device 22 which also functions as a paper discharge mechanism is disposed opposite to one end of the endless belt 18 on the opposite side to the paper feeding device 20 and the like in the stretching direction, and is stretched substantially horizontally. At a position facing the lower surface of the endless belt 18, a belt static eliminator 23 and a belt cleaner 24 are arranged to face each other.

The endless belt 18 has a structure in which a conductive layer (both not shown) is formed under the insulating layer located on the surface, and two rotating rollers 25, 26 which are in contact with the conductive layer. A ground line (not shown) is connected to one or the like. Further, a belt supporting roller 27 is arranged at a position facing the photosensitive drums 12 of the printing stations 17 _{1 to} 17 ₄ via the endless belt 18, and a power supply circuit (below the endless belt 18 is arranged. (Not shown) and the like are arranged.

Here, in the belt conveying device 10 of this embodiment, as shown in FIG.
One of the rotating rollers 25 and 26 that rotatably supports the crown roller is a crown roller whose central portion is expanded more than both end portions, and the other is an opposite roller whose both end portions are expanded compared to the central portion. It is a crown roller. More specifically, as illustrated in FIG. 1, the rotary rollers 25 and 26 are provided with a taper member 28 having an outer peripheral surface formed in a conical shape in which the other end is expanded as compared with one end. The taper member 28 is attached to both sides of the rotary shaft 29 so that the outer peripheral surface is inclined in the opposite direction. The shaft hole 30 of the taper member 28
On the inner peripheral surface of the rotary shaft 29 and the outer peripheral surface of the rotary shaft 29.
2 is formed, and two taper members 28 slidably fitted on the rotary shaft 29 with the keys 33 engaged with the key grooves 31 and 32 are fixed by stoppers 34. Therefore, in the belt conveying device 10, the direction of the taper member 28 mounted on the rotary shaft 29 is changed as described above, so that the rotary rollers 25 and 26 can be separated from the crown roller whose central portion is widened and both ends. It is formed as an anti-crown roller with a widened portion.

With such a structure, when a color image is printed by the color printer 11, the rotating photosensitive drum 12 in each of the printing stations 17 _{1 to} 17 ₄ has a drum cleaner 13 with dust such as residual toner on the outer peripheral surface. The electrostatic latent image formed by the optical scanning of the laser scanner 15 on the outer peripheral surface of the photosensitive drum 12 is removed by the color toner supplied from the developing device 16 in a single color. The image is developed. When such a printing station 17 a printing paper from _{1-17 4} operation in synchronization with the sheet feeding apparatus 20 onto the endless belt 18 (not shown) is fed, the printing paper sheet holding roller 19 When the transfer charger 21 applies a charge while being pressed and held on the endless belt 18, the printing paper is charged together with the endless belt 18, electrostatically attracted to the endless belt 18, and a transfer voltage is provided. To be done. Therefore, printing paper that is the transport of yellow, magenta and cyan, and black monochromatic images are sequentially superimposed printing from the photosensitive drum 12 of each printing station 17 ₁ to 17 ₄ on the surface, the fixing device is peeled from the endless belt 18 After being heated and pressurized at 22, it is discharged to the outside of the device.

On the other hand, the endless belt 18 from which the printing paper has been peeled off as described above continues to roll, and its surface is neutralized by the corona discharge of the belt neutralizer 23. And
The static-removed endless belt 18 has its dust and dirt attached to its surface removed by the belt cleaner 24 and stands by for the next printing.

Here, in the belt conveying device 10, as shown in FIG. 2, one of the pair of rotating rollers 25 and 26 is a crown roller and the other is an anti-crown roller, so that the belt is rolled. The belt 18 is prevented from being displaced in the axial direction, which contributes to improving the print quality of the color printer 11. Further, the endless belt 18 stretched by the rotating roller 25 whose central portion is expanded and the rotating roller 26 whose both ends are expanded are
Durability is good because the tension acting in the tension direction is substantially uniform. Further, in the belt conveying device 10, as described above, the rotating roller 2 having a shape in which the central portion and both end portions are expanded.
Since 5 and 26 are realized by a combination of one kind of conical taper member 28, it is easy to make the shape exactly symmetrical and the productivity is also good.

In the belt conveying device 10 of this embodiment, the endless belt 18 is stretched by the rotating roller 25 whose central portion is expanded and the rotating roller 26 whose both ends are expanded. The invention is not limited to the above-described structure, and as illustrated in FIG. 4A, a belt conveying device 35 in which the endless belt 18 is stretched by two rotating rollers 25 whose central portion is expanded, and the same. As illustrated in FIG. (B), a belt conveying device 36 in which the endless belt 18 is stretched by two rotating rollers 26 whose both ends are expanded can be implemented.

Further, in the belt carrying device 10 of the present invention, the two taper members 28 mounted on the rotary shaft 29 are directly joined, but the present invention is limited to the above structure. Instead, as illustrated in FIG. 5 and FIG. 6, a belt conveying device 39 in which a cylindrical member 37 is provided between two taper members 28 and a rotating roller 38 having an expanded central portion is formed can be implemented. .. In this belt conveying device 39, the rail-shaped ribs 40 are provided on the outer peripheral surface of the cylindrical member 37 located in the central portion so as to prevent the displacement of the endless belt 18 with higher accuracy. There is.

[0021]

As described above, according to the present invention, in the belt conveying device in which the endless belt is stretchably stretched by the plurality of rotatable rollers rotatably supported, the other end portion is compared to the one end portion. Is provided with a tapered member having an outer peripheral surface formed in a conical shape, and the two tapered members are mounted on a rotating shaft so that the inclination directions of the outer peripheral surfaces are opposite to each other, and at least one of the rotating rollers is attached. By forming it, it is possible to realize a rotating roller with a shape in which the central part and both ends are expanded with a combination of one type of taper member, so it is easy to accurately make the shape symmetrical and productivity is improved. It is possible to contribute to the improvement of the above, and it is possible to obtain a belt conveying device with good productivity.

[Brief description of drawings]

FIG. 1 is an exploded perspective view showing a rotating roller according to an embodiment of the present invention.

FIG. 2 is a plan view showing a belt conveying device.

FIG. 3 is a vertical sectional side view showing a color printer.

FIG. 4 is a plan view showing a modified example of the belt transport device.

FIG. 5 is an exploded perspective view showing a modified example of a rotating roller.

FIG. 6 is a plan view showing a belt transport device.

FIG. 7 is a perspective view showing a conventional example.

[Explanation of symbols]

 10, 35, 36, 39 belt transport device 25, 26, 38 rotating roller 28 taper member 29 rotating shaft

Claims (1)

[Claims] 1. A belt conveying device in which an endless belt is rotatably stretched around a plurality of rotating rollers rotatably supported, and the outer periphery is conical with the other end being wider than the one end. A belt characterized in that a taper member having a surface is provided, and at least one of the rotary rollers is formed by mounting the two taper members on a rotary shaft such that the outer peripheral surfaces are inclined in opposite directions. Transport device.