JP2009025609A - Belt, primary transfer belt for image forming apparatus, and image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a structure of an intermediate transfer belt that does not peel easily even if it is bent in the inside and outside directions, and an image forming apparatus having such an intermediate transfer belt. <P>SOLUTION: This image forming apparatus comprises one or more rollers for outward curve that travel along one or two or more photosensitive bodies and curve a primary transfer belt of a closed loop shape to which a toner image formed on the surface of the photosensitive body is transferred toward the outside of the closed loop, and one or more rollers for inward curve for curving the secondary transfer belt toward the inside of the closed loop. The primary transfer belt comprises a resin-made substrate layer formed inside the closed loop, and an elastic layer formed outside the substrate layer. The elastic layer is bonded to the substrate layer via an uneven boundary surface formed on the outer surface of the substrate layer. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an inner and outer two-layer belt, or an image forming apparatus using electrophotographic technology and a primary transfer belt for an image forming apparatus, and more particularly, a belt resistant to fatigue due to bending, a primary transfer belt, and the same The present invention relates to an image forming apparatus.

FIG. 4 is a front sectional view of an intermediate transfer unit B used in a conventional image forming apparatus. The intermediate transfer unit B has a closed loop shape in which a toner image formed on the surface of the photosensitive member 1 is transferred along the plurality of photosensitive members 1, 1,. A primary transfer belt 7 and a plurality of rollers R1 to R3 that stretch the closed loop primary transfer belt 7 so as to run can be provided. The rollers R1 to R3 are an example of one or more outward bending rollers that bend the primary transfer belt 7 toward the outside of the closed loop.
Four photoconductors 1 are provided corresponding to four colors, but the number of the photoconductors 1 is not particularly limited in the present invention. Corresponding to each photoreceptor 1, an exposure device 2, a developing device 3, a drum cleaning blade 4, a static eliminator 5, a charger 6, and a primary transfer roller 8 are provided.
The intermediate transfer unit B further includes a secondary transfer roller 10 that is an example of a secondary transfer unit that transfers the toner image transferred to the primary transfer belt onto the transfer material 14.
Reference numeral 9 is a registration roller, 11 is a conveyance belt for conveying a transfer material 14 onto which a toner image has been transferred, 12 is a primary transfer cleaning member for cleaning the primary transfer belt 7, and 13 is a fixing device.
In this type of image forming apparatus, when the primary transfer belt 7 is stretched by a plurality of rollers R1, R2,... (Three in FIG. 4) as shown in FIG. Since the container 13 or the primary transfer cleaning member 12 is inevitably placed outside the closed loop of the primary transfer belt 7, there is a problem that the entire intermediate transfer unit B is enlarged.
Therefore, in order to save the space of the entire intermediate transfer unit B, in Patent Document 1 and the like, as shown in FIG. 5, an inward bending roller R4 (described above) that curves the primary transfer belt 7 toward the inside of the closed loop. In Patent Document 1, the outer roller 80 corresponds to that).
As a result, a space between the triangular rollers R1 and R2 surrounded by the primary transfer belt 7 formed by the three rollers R1, R2, and R3 shown in FIG. 4 is recessed inward, and the recessed portion is formed in FIG. As shown in FIG. 4, the whole or a part of the fixing unit 13 or the primary transfer cleaning member 12 can be arranged, so that the whole intermediate transfer unit B can be downsized.
JP 2001-117374 A

On the other hand, in recent years, as the primary transfer belt 7, in order to maintain strength, as shown in FIG. 1, a high-strength resin base material layer 7a is provided in the inner layer portion, and rubber or the like is provided outside the base material layer 7a. The thing of the multilayer structure provided with the elastic layer 7b formed with this material is employ | adopted. The multilayer primary transfer belt 7 configured as described above uses a resin having a higher Young's modulus than rubber or the like for the inner layer portion, thereby increasing the rigidity of the entire belt, and the belt running speed generated by the belt expanding and contracting. Can be suppressed. In particular, a color image forming apparatus that superimposes a plurality of images in the form of a primary transfer belt can have the advantage that color misregistration can be reduced because the running speed of the primary transfer belt does not vary as described above. In addition, a coat layer that further enhances releasability may be formed on the surface.
The base material layer 7a of this laminated belt has a high hardness and a low elongation rate, and the elastic layer 7b has a relatively low hardness and a high elongation rate.
However, the laminated type primary transfer belt 7 is not only bent outwardly outside the closed loop space by the outward bending rollers R1, R2 and R3 as shown in FIG. In the configuration in which the inward bending roller R4 (outer roller 80 in Patent Document 1) is used to bend inward, the primary transfer belt 7 is repeatedly bent inward and outward.
Therefore, as shown in FIG. 2, when the bending is repeated, a stress is applied to the interface between the base material layer and the elastic layer, and the both layers are peeled off.
Such a problem is caused by the bending even when it is bent only in one direction (outward direction) by a plurality of rollers R1, R2, and R3 as shown in FIG. When the inward bending roller R4 is added to the inside and repeatedly bent inward and outward, this is a very serious problem due to the intensity of bending, and the primary transfer belt 7 causes the inner and outer layers to separate relatively early. ， There is a problem that the life is shortened.
Accordingly, the present invention has been made in view of the above circumstances, and a first object of the present invention is a closed loop that is stretched over two or more rollers including a driving roller and travels by rotating the driving roller. A belt having a shape of a belt formed of a resin base layer formed inside the closed loop and an elastic layer formed outside the base layer. The first and second objectives are to provide a belt structure that is not easily peeled even if the belt is composed of two or more layers that are repeatedly subjected to stress by bending. It is another object of the present invention to provide a multilayer primary transfer belt structure that does not easily peel off even when repeatedly bent and an image forming apparatus including such a primary transfer belt.

In order to achieve the first object, the present invention provides:
A closed loop belt that is stretched over two or more rollers including a drive roller and travels when the drive roller rotates, and a resin base layer formed inside the closed loop, and the base A belt comprising an elastic layer formed outside the layer,
The elastic layer or an adhesive layer for bonding the elastic layer to the base material layer is bonded to the base material layer through an uneven boundary surface formed on the outer surface of the base material layer. It is configured as a belt.
As a result, the contact area at the boundary between the base material layer and the elastic layer increases, and the bonding force between the base material layer and the elastic layer is strengthened even if the peeling force caused by repeatedly bending the belt acts on the boundary. As a result, both layers do not peel off, and the life of the belt can be extended.
In order to achieve the second object, the present invention provides:
One or two or more photoconductors, a closed loop primary transfer belt that runs along the photoconductor and onto which a toner image formed on the surface of the photoconductor is transferred, and a toner image transferred to the primary transfer belt Secondary transfer means for transferring onto the transfer material, one or more outward curving rollers for curving the primary transfer belt toward the outside of the closed loop, and curving the primary transfer belt toward the inside of the closed loop. An image forming apparatus including one or more inward bending rollers, wherein the primary transfer belt is formed on a resin base layer formed inside the closed loop and on the outside of the base layer. A primary transfer belt for an image forming apparatus, comprising:
The elastic layer or an adhesive layer for bonding the elastic layer to the base material layer is bonded to the base material layer through an uneven boundary surface formed on the outer surface of the base material layer. Configured as a primary transfer belt for an image forming apparatus.
As a result, the contact area at the boundary between the base material layer and the elastic layer increases, and even if the peeling force caused by repeatedly bending the primary transfer belt inward and outward acts on the boundary, the contact between the base material layer and the elastic layer. Since the bonding force is strengthened, both layers do not peel off, and the life of the primary transfer belt can be extended.
As an image forming apparatus equipped with such a long-life primary transfer belt,
One or two or more photoconductors, a closed loop primary transfer belt that runs along the photoconductor and onto which a toner image formed on the surface of the photoconductor is transferred, and a toner image transferred to the primary transfer belt Secondary transfer means for transferring onto the transfer material, one or more outward curving rollers for curving the primary transfer belt toward the outside of the closed loop, and curving the primary transfer belt toward the inside of the closed loop. An image forming apparatus including one or more inward bending rollers, wherein the primary transfer belt is formed on a resin base layer formed inside the closed loop and on the outside of the base layer. In an image forming apparatus comprising an elastic layer formed,
The elastic layer or an adhesive layer for bonding the elastic layer to the base material layer is bonded to the base material layer through an uneven boundary surface formed on the outer surface of the base material layer. An image forming apparatus is provided.

  As the shape of the unevenness, a cross-sectional shape perpendicular to the width direction of the primary transfer belt is typically provided such as a zigzag, a gear tooth shape, or a wavy shape. Further, the unevenness may be constituted by a plurality of protrusions or depressions formed by projecting or sinking in the thickness direction of the primary transfer belt 7. What is necessary is just to increase compared with the case.

According to the present invention, a closed loop belt that is stretched over two or more rollers including a drive roller and travels as the drive roller rotates, and is a resin base material formed inside the closed loop. In a belt comprising a layer and an elastic layer formed outside the base material layer, the elastic layer or an adhesive layer that joins the elastic layer to the base material layer is formed of the base material layer. A belt is provided which is bonded to the base material layer through an uneven surface formed on the outer surface.
This makes it possible to extend the life of the belt.
Also, one or more photosensitive members, a closed-loop primary transfer belt that travels along the photosensitive member and transfers a toner image formed on the surface of the photosensitive member, and toner transferred to the primary transfer belt Secondary transfer means for transferring an image onto a transfer material, one or more outward bending rollers for bending the primary transfer belt toward the outside of the closed loop, and the primary transfer belt toward the inside of the closed loop. An image forming apparatus comprising one or more inward bending rollers for bending, wherein the primary transfer belt includes a resin base layer formed inside the closed loop, and an outer side of the base layer And an elastic layer formed on the outer surface of the base material layer, wherein the elastic layer or the adhesive layer that joins the elastic layer to the base material layer is formed on the outer surface of the base material layer. The boundary of Thus, an image forming apparatus characterized by being bonded to the base material layer is provided, whereby an image forming apparatus having a primary transfer belt that is less likely to cause peeling of the inner and outer layers is provided. Is prolonged.

Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings so that the present invention can be understood. The following embodiment is an example embodying the present invention, and does not limit the technical scope of the present invention.
1 is a general cross-sectional view of the primary transfer belt, FIG. 2 is a diagram showing an outline of the primary transfer belt that is bent inward and outward, and a state in which the primary transfer belt is damaged, and FIG. FIG. 4 is a cross-sectional view of a primary transfer belt showing a comparison between a conventional primary transfer belt and a primary transfer belt according to an embodiment of the present invention, FIG. 4 is a schematic configuration diagram of a conventional intermediate transfer unit, and FIG. FIG. 6 is a conceptual diagram illustrating an example of a manufacturing procedure of the primary transfer belt according to the present embodiment.

In this embodiment, as described below, one or more photosensitive members, a closed-loop primary transfer belt that travels along the photosensitive member and onto which a toner image formed on the surface of the photosensitive member is transferred, Secondary transfer means for transferring the toner image transferred to the primary transfer belt onto a transfer material, one or more outward bending rollers for bending the primary transfer belt toward the outside of the closed loop, and the primary transfer belt Although the present invention will be described with reference to a primary transfer belt used in an image forming apparatus including one or more inwardly bending rollers that bend inward toward the inside of the closed loop, the present invention is limited to such a case. A closed-loop belt that is stretched over two or more rollers including at least a driving roller and travels by rotating the driving roller, A general belt comprising a resin base layer formed inside and an elastic layer formed outside the base layer can also be bent when two or more belts are bent. Of course, the peeling force acts on the inner and outer layers.
Hereinafter, the case of the primary transfer belt used in the image forming apparatus will be described.
As shown in FIG. 5, the intermediate transfer unit A of the image forming apparatus according to this embodiment uses a primary transfer belt 7 supported by a plurality of rollers R1, R2, R3, and R4 as an intermediate transfer member. In contact with the primary transfer belt 7, photoconductors 1, 1,... Made of amorphous silicon for yellow, magenta, cyan, and black are arranged. Around each photoconductor 1, an exposure device 2, a developing device 3, a drum cleaning blade 4, a static eliminator 5, and a charger 6 are provided. A latent image is formed by the exposure device 2 on the uniformly charged photoreceptor 1 by the charger 6, and an image visualized by each color toner is formed by the developing device 3. The formed color toner images are primarily transferred onto the primary transfer belt 7 in the order of each color. Thus, a toner image is formed on the surface of the primary transfer belt 7.

The toner remaining on the photosensitive member 1 without being primarily transferred is removed by the drum cleaning blade 4 and is neutralized by the static eliminator 5 to refresh the photosensitive member 1. The full-color image thus formed on the primary transfer belt 7 is secondarily transferred by the secondary transfer roller 10 (an example of a secondary transfer unit) onto the transfer material P sent out by the registration roller 9 in time. .
The transfer material P onto which the toner image has been secondarily transferred is conveyed to the fixing device 13 by the conveyance belt 11. The fixing device 13 is partly disposed in a space formed by the primary transfer belt 7 being curved inward by the fourth roller R4, so that the entire intermediate transfer unit A can be reduced in size. ing. Since the entire primary transfer cleaning member 12 is installed in the space created by bending the primary transfer belt 7 inwardly, the contribution to miniaturization of the entire intermediate transfer unit A is reduced. high.

However, in the intermediate transfer unit A according to this embodiment, in addition to the three rollers R1, R2, and R3 that bend the primary transfer belt 7 outward from the closed loop space as described above, the primary transfer belt 7 By providing the roller R4 that bends inward from the closed loop space, the primary transfer belt 7 is repeatedly bent inward and outward each time it rotates once. For this reason, the peeling force generated at the boundary surface between the inner layer and the outer layer of the primary transfer belt 7 shown in FIG. 2 is increased, which causes the life of the primary transfer belt 7 to be shortened.
Also in the primary transfer belt 7 according to this embodiment, as shown in FIGS. 1 and 2, an elastic layer 7b is provided outside the base material layer 7a made of resin formed inside the closed loop, thereby improving running performance and high performance. As shown in FIG. 3, a groove having a depth of 10 μm is formed in a cross section perpendicular to the width direction of the primary transfer belt 7 at the boundary surface where the base material layer 7a is in contact with the elastic layer 7b. By providing them at an interval of 10 μm, a belt of the base material layer 7 a having an uneven shape on the surface is generated. The uneven shape formed on the surface of the base material layer 7a may be an N-shaped shape (that is, a zigzag shape) as shown in FIG. 3A or a wave shape as shown in FIG. 3B. Alternatively, the shape of gear teeth may be used as shown in FIG.
Of course, other irregularities may be used. In short, the surface of the contact surface between the base material layer 7a and the outer elastic layer 7b may be larger than the conventional flat surface. ), A large number of hemispherical protrusions or depressions projecting or sinking in the belt thickness direction, or irregularities are formed when the surface is moderately roughened, increasing the area of the contact surface. It may be something like this.

As an example, the thickness of the base material layer 7a may be about 100 μm. PVDF or PI, PAI, PC, ETFE or the like can be used as the resin material constituting the base material layer 7a. A CR rubber, urethane rubber, silicon rubber, NBR rubber, EPDM, or the like is formed as an elastic layer on the resin belt of the base material layer 7a having the uneven shape as a thickness of 100 μm. Thus, by making the interface between the base material layer and the elastic layer uneven, the contact area between both layers is increased, and the binding force between the two layers is increased.
Further, the volume resistivity of the base material layer 7a and the elastic layer 7b are both substantially matched in the range of 10 ⁸ to 10 ¹² Ω · cm. This eliminates the difference in resistance between the convex and concave portions of the concavo-convex shape and concentrates the current on the low resistance portion, thereby preventing transfer unevenness and image defects. It should be noted that it is desirable to select a material having good compatibility between the base material and the elastic material and easy to bond to the base material layer 7a and the elastic layer 7b, but between the base material layer 7a and the elastic layer 7b. Another adhesive layer may be provided.

As a method for forming the elastic layer 7b or the adhesive layer outside the base material layer 7a as described above, a centrifugal force method can be used.
FIG. 6 shows a procedure for manufacturing the primary transfer belt 7 in which the elastic layer is bonded to the base material layer by such a centrifugal force method. The elastic layer may be replaced with an adhesive layer.
Prior to manufacture, the inner surface of a ring-shaped cylindrical mold 20 as shown in FIG. 6A is formed on the inner surface of the ring-shaped mold 20 as shown in FIG. ) Is formed. The unevenness may be jagged or corrugated, or a protrusion, a dent, or a rough surface.
Next, while the mold 20 is rotated about an axis perpendicular to the paper surface, the raw material of the base material layer 7a is injected into the inner surface of the mold 20 (c), and the raw material is applied to the inner surface of the mold 20 by centrifugal force. The belt 24 that forms the seamless closed-loop base material layer 7a is formed by spreading evenly and solidifying as the temperature decreases. At this time, as shown in (d), irregularities are formed on the outer surface of the belt 24 according to the irregularities formed on the inner surface of the mold 20.

When the belt 24 is solidified and completed, the belt 24 is removed from the mold 20, and a rubber material 26 is applied to form the elastic layer 7b on the surface of the belt 24 where the irregularities are formed (e). .
Subsequently, the rubber material 26 is vulcanized to complete the elastic layer 7b (f).
Finally, the material 28 which forms the release layer on the outermost layer is sprayed and cured by heating (g).
The primary transfer belt 7 having an increased contact area is produced by forming irregularities on the boundary surface between the inner and outer layers by the above-described process.

FIG. 3 is a general cross-sectional view of a primary transfer belt. The figure which shows the outline of the spanning state of the primary transfer belt which is bent in the inside and outside directions, and the state where it is damaged. FIG. 3 is a cross-sectional view of a primary transfer belt showing a comparison between a conventional primary transfer belt and a primary transfer belt according to an embodiment of the present invention. Schematic configuration diagram of a conventional intermediate transfer unit. 1 is a schematic configuration diagram of an intermediate transfer unit according to an embodiment of the present invention. The conceptual diagram which shows an example of the manufacture procedure of the primary transfer belt concerning this embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Photoconductor 2 ... Exposure device 3 ... Developer 4 ... Drum cleaning blade 5 ... Charge remover 6 ... Charger 7 ... Primary transfer belt 7a ... Base material layer 7b ... Elastic layer 8 ... Primary transfer roller 10 ... Secondary transfer roller P: Transfer material

Claims (5)

A closed loop belt that is stretched over two or more rollers including a drive roller and travels when the drive roller rotates, and a resin base layer formed inside the closed loop, and the base A belt comprising an elastic layer formed outside the layer,
The elastic layer or an adhesive layer for bonding the elastic layer to the base material layer is bonded to the base material layer through an uneven boundary surface formed on the outer surface of the base material layer. To belt. One or two or more photoconductors, a closed loop primary transfer belt that runs along the photoconductor and onto which a toner image formed on the surface of the photoconductor is transferred, and a toner image transferred to the primary transfer belt Secondary transfer means for transferring onto the transfer material, one or more outward bending rollers that curve the primary transfer belt toward the outside of the closed loop, and the primary transfer belt to curve toward the inside of the closed loop. An image forming apparatus including one or more inward bending rollers, wherein the primary transfer belt is formed on a resin base layer formed inside the closed loop and on the outside of the base layer. A primary transfer belt for an image forming apparatus, comprising:
The elastic layer or an adhesive layer for bonding the elastic layer to the base material layer is bonded to the base material layer through an uneven boundary surface formed on the outer surface of the base material layer. A primary transfer belt for an image forming apparatus. One or two or more photoconductors, a closed loop primary transfer belt that runs along the photoconductor and onto which a toner image formed on the surface of the photoconductor is transferred, and a toner image transferred to the primary transfer belt Secondary transfer means for transferring onto the transfer material, one or more outward bending rollers that curve the primary transfer belt toward the outside of the closed loop, and the primary transfer belt to curve toward the inside of the closed loop. An image forming apparatus including one or more inward bending rollers, wherein the primary transfer belt is formed on a resin base layer formed inside the closed loop and on the outside of the base layer. In an image forming apparatus comprising an elastic layer formed,
The elastic layer or an adhesive layer for bonding the elastic layer to the base material layer is bonded to the base material layer through an uneven boundary surface formed on the outer surface of the base material layer. Image forming apparatus.   The image forming apparatus according to claim 3, wherein the unevenness has a cross-sectional shape perpendicular to the width direction of the primary transfer belt that is any of a zigzag, a gear tooth shape, and a wavy shape.   The image forming apparatus according to claim 3, wherein the unevenness includes a plurality of protrusions or depressions formed in a thickness direction of the primary transfer belt.

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