JPH08165037A - Recording material conveying device and image forming apparatus using the same - Google Patents

Abstract

(57) [Summary] [Purpose] In the recording material conveying device in the image forming apparatus,
To prevent deviation of the annular belt that conveys the recording material without complicating the apparatus. In a recording material conveying device in an image forming apparatus for forming a monochrome image or a color image, a substantially cylindrical roller (2) serving as a supporting means of an annular belt body (3) for conveying the recording material, or a substantially half roller. At least one of the cylindrical guides is provided with an abutment member (16) with which the annular belt body is abutted, and a tapered member (17) for holding the abutment of the annular belt body to the abutting member is provided. , The guide is provided on the side opposite to the contact member with the annular belt body sandwiched, the diameter of the tapered member on the small diameter side is smaller than the diameter of the guide, and the diameter on the large diameter side is smaller than the diameter of the guide. With a large structure, the annular belt body is brought into contact with the abutting member, the deviation of the annular belt body is prevented, and the recording material is stably conveyed with high accuracy.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a recording material conveying device in an image forming apparatus for forming a monochrome or color image.

[0002]

2. Description of the Related Art Image forming apparatuses frequently used in offices and the like, especially copying machines and printers, are required to have high image quality, and high accuracy is required for conveying recording materials in the image forming apparatus. .

An apparatus using an annular belt body is well known as a conveying means of a recording material conveying device for conveying a recording material while stably maintaining high position accuracy. This annular belt is supported by a plurality of rollers, semi-cylindrical guides, or a combination thereof, and is driven by a drive roller, etc. Unstable lateral shift due to error
When the "deviation" becomes large, the annular belt body is bent and distorted, which leads to defective conveyance of the recording material.
Therefore, as shown in JP-A-6-87566, etc., the inclination of one of the rollers supporting the annular belt body is controlled,
A recording material conveying device has been proposed which prevents an unstable “shift” of the annular belt body.

[0004]

However, according to the recording material conveying apparatus described above, a sensor for measuring the "deviation" of the annular belt body, an actuator for inclining the roller, etc. are required, and the apparatus is large in size. Complexity,
This leads to higher costs. Further, basically, the movement of the annular belt member in the roller longitudinal direction is not eliminated, and if there is such movement during the conveyance of the recording material, it also contributes to defective conveyance.

Therefore, the present invention does not increase the size, complexity, and cost of the recording material conveying device, and further prevents lateral movement of the annular belt member to stably convey the recording material with high accuracy. The purpose is to do.

[0006]

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and in a recording material conveying device in an image forming apparatus for forming a monochrome image or a color image, the recording material conveying member has an annular shape. A belt member is provided, and at least one of a substantially cylindrical roller or a substantially semi-cylindrical guide that is a supporting means of the annular belt member is provided with a contact member with which the annular belt member is in contact. A tapered member for holding the contact of the annular belt body with the contact member,
The substantially cylindrical roller or the semi-cylindrical guide is provided on the opposite side of the contact member from the contact member, and the diameter of the tapered member on the small diameter side is the substantially cylindrical roller or the substantially cylindrical roller. The diameter is smaller than the diameter of the semi-cylindrical guide, and the diameter on the large diameter side is larger than the diameter of the substantially cylindrical roller or the substantially semi-cylindrical guide.

Further, the belt contact member may be biased by the elastic member to the side plate holding the substantially cylindrical roller or the substantially semi-cylindrical guide.

Further, at least two of the plurality of substantially cylindrical rollers or the substantially semi-cylindrical guides are provided with the belt contact member and the tapered member, respectively, and the elastic member serves to support the belt. The side plate biased by the contact member may be common, and the belt contact member may also serve as the side plate holding the substantially cylindrical roller or the substantially semi-cylindrical guide.

Further, among the plurality of substantially cylindrical rollers or the substantially semi-cylindrical guides, at least two of them are respectively provided with the tapered members, and the belt abutting member also serving as the side plate is common. The contact portion with which the annular belt member contacts may be only near the substantially cylindrical roller or the substantially semicylindrical guide.

Further, the tapered member and the belt contact member may be made of a material having a high slidability, and at least one of the supporting means for supporting the annular belt body is a rubber roller for driving the annular belt body. Can also be

Further, a charge applying means for electrostatically attracting the recording material to the belt-shaped body may be provided, the image forming means in the image forming apparatus is an electrophotographic system, and the annular belt body also serves as a transfer belt. May be.

A flange-shaped rib may be provided on the large diameter side of the tapered member.

[0013]

According to the above construction, the recording material is formed in a state in which the annular belt material which is the conveying means is brought into contact with the belt contact member by the taper member without causing the size, complexity and cost of the recording material. Since it is driven, it is transported without any lateral displacement.

[0014]

Embodiments of the present invention will be described below with reference to the drawings.

<Embodiment 1> FIG. 1 is an overall structural view of a recording material conveying apparatus of a first embodiment of the present invention, and FIG. 2 is a sectional view of the vicinity of a belt driving roller of the first embodiment.

The present embodiment is a recording material conveying apparatus in a four-color (for example, four colors of yellow, magenta, cyan, and black) color image forming apparatus provided with four electrophotographic image forming means. As shown in FIG. 1, reference numeral 1 is a recording material conveying means, which is a supporting roller for supporting an annular belt body 3 also serving as a transfer belt, and 2 is a drive for driving the annular belt body 3 by frictional resistance of a rubber layer formed on the surface thereof. Roller 4 is recording material P
A cassette for storing the recording material P, a feeding roller for feeding the recording material P, a feeding guide 6, a photosensitive drum 7a, 7b, 7c, 7d, and photosensitive drums 7a, 7d 8a, 8b, 8c, 8d.
b, 7c and 7d are exposed to light according to image information to form an electrostatic latent image, and 9a, 9b, 9c and 9d are developing units for adhering toner to the electrostatic latent image to develop as a toner image, 1
The toner images of 0a, 10b, 10c, and 10d are the recording materials P.
A cleaner for removing residual toner remaining after being transferred by the transfer means 11a, 11b, 11c, 11d,
Reference numeral 12 is a separation corona for separating the recording material P from the annular belt body 3, 13 is a pre-fixing guide, 14 is a fixing device for permanently fixing the toner transferred onto the recording material onto the recording material by heat or the like, 15
Is a paper ejection tray.

In FIG. 2, 16 is a belt contact member made of a slidable material, 17 is a tapered member made of a slidable material having a flange-shaped rib 17 ', 18 and 19 are bearings, and 20 and 21 are shown. Is a bearing cover, and 22 and 23 are side plates for holding the support roller 1 and the drive roller 2. Note that FIG.
Shows a cross section in the vicinity of the driving roller 2, but the vicinity of the supporting roller 1 has the same structure.

The operation of this embodiment will be described below.

First, the recording material P is guided from the cassette 4 by the feeding roller 5 to the feeding guide 6 and fed one by one to the vicinity of the support roller 1 of the annular belt body 3, and the transfer means 11a, 11 are provided.
It is electrostatically adsorbed on the annular belt body 3 to which a charge is given by any or all of b, 11c and 11d. In parallel with this process, image formation is performed by the electrophotographic image forming means. Since the four-color image forming means all perform the same operation, description will be made using common symbols with the subscripts (a, b, c, d) omitted. The photosensitive drum 7 is exposed by the exposure unit 8 in accordance with each color information, an electrostatic latent image is formed, and a toner image is developed on the electrostatic latent image by the developing device 9. When the recording material P reaches the transfer means 11, the toner image starting portion also reaches that position by the rotation of the photosensitive drum 7, and the transfer means 11 transfers the toner image onto the recording material P. This image forming process is repeated four times by the four image forming means, and when the recording material P reaches the drive roller 2, it is separated from the annular belt body 3 by the separation corona 12 and the fixing device 14 via the pre-fixing guide 13. After the toner image is permanently fixed on the recording material P by the heat, the recording material P is ejected to the paper ejection tray 15.

Here, the operation of the tapered member and the like will be described with reference to FIG. Bearings 18, 19, bearing covers 20, 21
When the drive roller 2 rotatably held by the side plates 22 and 23 is rotated by a belt drive motor (not shown), the diameter of the large diameter portion of the tapered member 17 of the annular belt body 3 is larger than that of the drive roller 2. Since the diameter of the small-diameter portion is smaller than the diameter of the drive roller, the taper member 17 has a shape that is slightly concavely curved on the slope, and the taper member 17 is a slidable material and slides on the slope. A force that moves toward the middle B direction, that is, toward the contact member 16 side acts. The annular belt body 3 that has been moved in the B direction hits the belt contact member 16 and the position in the B direction becomes stable there. After that, the force in the B direction on the annular belt body 3 constantly acts on the inclined surface of the tapered member 17, so that the position of the annular belt body 3 in the B direction is completely determined.

A flange-shaped rib 17 'is provided on the large-diameter side of the tapered member 17 so that the annular belt does not come off from the drive roller 2 even if the annular belt approaches the side opposite to the B direction due to impact or the like. Has become.

Further, the supporting roller 1 side has the same structure and operates in the same manner. Further, there is a rib 17 'on the flange on the large diameter side of the tapered member 17, so that even if the annular belt body approaches the side opposite to the B direction due to impact or the like, the driving roller 2
It does not come off.

As described above, in the present embodiment, the annular belt member is simply positioned in the roller axis direction to stably convey the recording material, and the relative displacement of the images by the four image forming means does not occur. .

<Embodiment 2> FIG. 3 is a sectional view showing the vicinity of a belt driving roller according to a second embodiment of the present invention.

The structure of this embodiment is the same as that of the first embodiment except for the vicinity of the belt driving roller and the supporting roller, and the description of the image forming means will be omitted. As shown in FIG.
Is a driving roller, 103 is an annular belt member, 116 is a belt contact member, 117 is a taper member having a flange-shaped rib 117 ′, 118 and 119 are bearings, 120 and 121 are bearing covers, and 122 and 123 are roller shafts. Side plate to hold,
Reference numeral 124 is a washer that engages with the shoulder portion 102a, and 125 is a spring. Similar to the first embodiment, the support roller side has the same structure as the drive roller 102 side, and further, the belt contact member 1
The supporting roller and the driving roller 102 are commonly supported by the side plate 122 on the 16 side.

Next, the operation of this embodiment will be described. As in the first embodiment, as the drive roller 102 rotates, the annular belt body 103 is brought into contact with the belt contact member 116 by the action of the tapered member 117, and the positioning is performed. Here, the roller 102 and the belt contact member 116 are brought into contact with the bearing 119 attached to the side plate 122 that holds the support roller and the drive roller 102 in common by the force of the spring 125 via the washer 124. As a result, the play between the belt contact member 116 and the side plate 122 is eliminated on both the support roller side and the drive roller side, and the relative position difference between the support roller side and drive roller side contact portions of the annular belt body 103 decreases. Further, the position of the annular belt body 103 in the B direction becomes stable.

As described above, in this embodiment, as compared with the first embodiment, the position of the annular belt member is more stable, and accordingly, the recording material P can be conveyed with higher accuracy.

<Embodiment 3> FIG. 4 is a diagram for explaining a recording material conveying apparatus according to a third embodiment of the present invention.

The construction of this embodiment is the same as that of the first embodiment except for the contact portion of the belt annular body, and the other description will be omitted.

In the present embodiment, the side plate on which the belt contact member, the supporting roller and the driving roller are held in common is integrated to make the structure simpler. As shown in FIG. 4, 201 is a supporting roller for supporting the annular belt body 203, 202 is a driving roller for driving the annular belt body 203, 222 is a side plate 217 having a supporting roller holding portion 222a and a driving roller holding portion 222b, Reference numeral 224 is a tapered member similar to the above embodiment.

Like the first and second embodiments, the drive roller 20 is used.
When the annular belt body 203 is driven by 2, the annular belt body 203 is gradually moved toward the opposite side of the tapered members 217 and 224 in the axial direction of the roller by the tapered members 217 and 224, and each roller of the side plate 222 is held. Part 222
It abuts around a and 222b. In addition, the side plate 222 includes the annular belt body 2 except for the roller holding portions 222a and 222b.
03 has a notched shape so as not to abut, so that a large frictional load is not applied to the annular belt body 203.

As described above, in this embodiment, the annular belt body is positioned with a simpler structure than that of the first embodiment, and the recording material conveying accuracy is improved.

Further, in the above-mentioned embodiments, the image formation is explained by the example of the color image formation and the example of the cylindrical roller as the supporting means of the belt is explained. Of course, it can be applied to a cylindrical guide.

[0034]

As described above, according to the present invention,
It is possible to prevent the unstable "close-up" of the annular belt body and to stably convey the recording material with high accuracy without increasing the size, complexity, and cost.

[Brief description of drawings]

FIG. 1 is a diagram illustrating a recording material conveying device according to a first embodiment of the present invention.

FIG. 2 is a cross-sectional view of the vicinity of a belt driving roller according to the first embodiment of this invention.

FIG. 3 is a sectional view around a belt drive roller according to a second embodiment of the present invention.

FIG. 4 is a diagram illustrating a recording material conveying device according to a third embodiment of the present invention.

[Explanation of symbols]

1,201 ... Support rollers 2,102,2
02 ... Driving roller 3, 103, 203 ... Annular belt body 16, 116 ...
Belt contact member 17, 117, 217, 224 ... Tapered member 22, 23, 122, 123, 222 ... Side plate 125 ... Spring P ... Recording material

Claims (11)

[Claims] 1. A recording material conveying device in an image forming apparatus for forming a monochrome image or a color image, wherein the recording material conveying member comprises an annular belt member, and a substantially cylindrical roller as a supporting means of the annular belt member. Alternatively, at least one of the substantially semi-cylindrical guides is provided with an abutting member with which the annular belt body is abutted, and a tapered member for holding the abutting of the annular belt body to the corresponding abutting member, The substantially cylindrical roller or the semi-cylindrical guide is provided on the opposite side of the contact member from the contact member, and the diameter of the tapered member on the small diameter side is the substantially cylindrical roller or the substantially cylindrical roller. A recording material conveying device, which is smaller than the diameter of the semi-cylindrical guide and whose diameter on the large diameter side is larger than the diameter of the substantially cylindrical roller or the substantially semi-cylindrical guide. 2. The recording material conveying apparatus according to claim 1, wherein the tapered member is urged by an elastic member toward a side plate holding the substantially cylindrical roller or the substantially semicylindrical guide. . 3. A belt contact member and a taper member are respectively provided on at least two of a plurality of substantially cylindrical rollers or substantially semi-cylindrical guides, and the belt contact member is provided by the elastic member. 3. The recording material conveying device according to claim 2, wherein the side plate on which the contact member is biased is common. 4. The belt contact member is the substantially cylindrical roller,
2. The recording material conveying device according to claim 1, which also functions as a side plate for holding the substantially semi-cylindrical guide. 5. A plurality of substantially cylindrical rollers or substantially semi-cylindrical guides, at least two of which are respectively provided with the tapered members, and which have a common belt contact member which also functions as the side plate. 5. The recording material conveying device according to claim 4, wherein the abutting portion with which the annular belt member abuts is only near the substantially cylindrical roller or the substantially semicylindrical guide. 6. The taper member and the belt contact member are made of a material having high slidability.
The recording material conveying device described. 7. The recording material conveying apparatus according to claim 1, wherein at least one of the supporting means for supporting the annular belt body is a rubber roller for driving the annular belt body. 8. The recording material conveying apparatus according to claim 1, wherein a flange-shaped rib is provided on the large diameter side of the tapered member. 9. The recording material conveying apparatus according to claim 2, wherein the elastic member for urging the belt contact member is a spring. 10. An image forming apparatus using the recording material conveying device according to claim 1, further comprising a charge applying means for electrostatically adsorbing the recording material to the belt-shaped body. 11. The image forming apparatus according to claim 10, wherein the image forming means in the image forming apparatus is an electrophotographic system, and the annular belt body also serves as a transfer belt.