JPH04303870A - Endless belt for intermediate transfer - Google Patents

Abstract

PURPOSE:To eliminate the distortion and dislocations of toner images by distributing numerous fine grooves inclined in the longitudinal direction of the belt on the outside surface thereof. CONSTITUTION:The endless belt 7a for intermediate transfer is constituted of thermoplastic resins, such as polycarbonate and polypropylene, and the numerous fine grooves 7b inclined in the longitudinal direction of the belt 7a are formed over the entire surface of the outside surface thereof. These fine grooves 7b are formed by assuming a lines 7c intersecting with the driving direction of the belt 7a and are so inclined that the angle theta formed by this virtual line 7c and the fine grooves 7b attains 30 deg.<=theta<=60 deg.. The depth of the fine grooves 7b is set at <=2/3 the grain size of toner, particles B. Then, the adequate contact friction of the outside surface of the endless belt 7a for intermediate transfer and a cleaning blade is obtd. and the unequal rotation and partial slack of the endless belt 7a for intermediate transfer are eliminated.

Description

[Detailed description of the invention]

0001

[Industrial Application Field] This invention relates to an intermediate transfer endless belt for transferring a toner image formed on a photoreceptor to its own outer surface and retransferring it to copy paper in an electrophotographic copying machine or the like. It is related to.

0002

[Prior Art] A full-color toner image formed on a photoreceptor is first transferred onto the outer peripheral surface of an intermediate transfer endless belt made of thermoplastic resin, and then transferred again to copy paper. A modern full-color electrophotographic copying machine is normally configured as shown in FIG. That is,
This electrophotographic copying machine includes an optical device 2 that guides light reflected from an original 1, a filter 3 that separates the reflected light from the original into three primary colors of red, green, and blue, and a belt-shaped photoreceptor 4 having photoconductivity. , a developing device 5, an intermediate transfer endless belt 7 that temporarily transfers the toner image formed on the photoreceptor 4 onto its outer peripheral surface before copying it onto copy paper 6, and a fixing device 8. More specifically, a charger 9 is provided near the starting end of the photoconductive belt-shaped photoconductor 4, and three developing sections 5a to 5a are provided in the middle of the photoconductor 4.
5c is provided. After the belt-shaped photoreceptor 4 is charged by the charger 9, it is exposed to light reflected from the original projected from the optical device 2, and an electrostatic latent image is formed thereon. In this case, the reflected light of the original is transferred to the photoreceptor 4.
As described above, the projection path of the optical device 2 is provided with a filter 3 that separates the reflected light from the original into the three primary colors of red, green, and blue. Then, the green light and so on are sequentially guided onto the belt-shaped photoreceptor 4 to form respective electrostatic latent images. The developing device 5 includes three developing sections 5a, 5b, and 5c corresponding to the above three primary colors, each containing toner of three different colors corresponding to the separated three primary colors. . The latent image formed by the color-separated light is colored and developed with toner corresponding to the color. That is, a colored toner image is formed for each color using the above-mentioned three kinds of toners, and this is sequentially transferred onto the outer surface of the intermediate transfer endless belt 7 by the action of the primary transfer roller 10. Forms a full-color toner image. In this way, the above-mentioned copying machine sequentially transfers colored toner images formed for each color onto copy paper 6, and instead of forming colored toner images on copy paper 6, it expands and contracts due to humidity, etc. A colored toner image is once formed on the intermediate transfer endless belt 7. Then, transfer the toner image to paper cassette 1.
The image is retransferred onto copy paper 6 supplied from 1 by the action of a secondary transfer roller 12. The retransferred full-color toner image is sent to a fixing device 8 as the copy paper 6 is transported and is fixed thereon, and the copy paper 6 with the toner image fixed thereon is sent out from the copying machine in the direction of the arrow. 13 is a conveyor belt.

0003

In an electrophotographic copying machine having such a structure, the full-color toner image formed on the outer peripheral surface of the endless intermediate transfer belt 7 is retransferred onto the copy paper 6. The residual toner is removed from the intermediate transfer endless belt 7.
remain on top. This residual toner is removed by the cleaning device 1
4 (see FIG. 7)
It is scraped off and removed by the scraping action of. As a result, the remaining toner is completely removed from the outer circumferential surface of the endless intermediate transfer belt 7, and the belt waits for the transfer of the next toner image. As described above, since a full-color toner image is formed on the outer surface of the intermediate transfer endless belt 7, it is desirable that the outer surface has a smooth and mirror-like finish. The outer peripheral surface of the belt 7 is finished in a mirror finish. However, in a copying machine equipped with such an endless intermediate transfer belt 7, the intermediary endless transfer belt 7 and the drive roller may slip or loosen over time, which may cause the full-color toner image transferred from the photoconductor to deteriorate. Distortion and misalignment (resulting in misalignment of the colored images constituting the full-color toner image) are occurring, and solving these problems has become an important problem.

The present invention was made in view of the above circumstances, and an object thereof is to provide an intermediate transfer endless belt that does not cause distortion or positional shift in toner images transferred from a photoreceptor. shall be.

[0005]

[Means for Solving the Problems] In order to achieve the above object, the intermediate transfer endless belt of the present invention is stretched around a plurality of rollers, and in the process of being circulated and driven, the belt transfers images onto its own outer surface. The intermediate transfer endless belt retransfers the toner image on the photoreceptor onto copy paper and removes the remaining toner particles with a cleaning blade.The outer surface of the endless belt has numerous belts that are inclined with respect to the longitudinal direction of the belt. It has a structure in which fine grooves are formed in a distributed manner.

[0006]

[Function] As a result of a series of studies to solve the major problems of toner image distortion and misalignment, the inventors found that the above-mentioned adverse phenomenon was caused by the endless intermediate transfer belt and the cleaning blade in contact with it. It was determined that this was caused by contact friction. Therefore, as a result of further research focusing on this, it was found that reducing the coefficient of friction on the surface of the endless intermediate transfer belt prevents the occurrence of the above-mentioned adverse phenomenon, and for that reason, the outer surface of the endless intermediate transfer belt is processed to have a rough surface. did. However, if the outer surface is made too rough, the quality of the toner image transferred from the photoreceptor will deteriorate. Therefore, the present inventors adjusted the quality of this toner image and the reduction of the friction coefficient,
The inventors have discovered that the best result can be achieved by forming numerous inclined fine grooves on the outer surface of the belt, and have arrived at the present invention. As a result, the intermediate transfer endless belt of the present invention does not cause distortion or positional shift in the toner image transferred from the photoreceptor, and also does not cause deterioration in image quality.

Next, an example will be explained.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows an intermediate transfer endless belt 7a according to an embodiment of the present invention. This intermediate transfer endless belt 7a
is installed in a full-color electrophotographic copying machine shown in FIG.

【Example】

The intermediate transfer endless belt 7a is made of a thermoplastic resin such as polycarbonate or polypropylene, and the entire outer surface thereof is provided with countless fine grooves 7b that are inclined with respect to the longitudinal direction of the belt 7a. It is formed. The fine groove 7b is formed by imagining a line 7c perpendicular to the driving direction of the belt 7a (the direction of the arrow in FIG. 1), and the angle θ formed by this imaginary line 7c and the fine groove 7b is 30°≦θ≦
60° (in Figure 1, θ is approximately 4
5°). The depth of the fine grooves 7b is usually set to 1/2 or less of the diameter of the toner particles B, as shown in FIG. However, when the upper edge of the groove wall of the fine groove b is chamfered in a rounded shape as shown in FIG. is possible. The average particle size of the toner particles B is usually 8
The depth of the fine grooves 7b distributed on the outer surface of the endless intermediate transfer belt is set to about μm.
It is usually 4 μm or less, and is set to 5.4 μm or less when the upper edge of the groove wall is rounded. Further, the formation interval of the fine grooves 7b is usually such that one side edge of a certain fine groove 7b and the other side edge of another fine groove 7b adjacent thereto are
The depth is set to match the depth of the fine groove 7b. However, there is no problem even if they are formed densely without any spacing. By doing this, the contact friction between the outer surface of the intermediate transfer endless belt 7a and the cleaning blade becomes appropriate, and rotational unevenness or partial sag does not occur on the intermediate transfer endless belt 7a, thereby preventing the transfer from the photoreceptor. This eliminates distortion and misalignment of full-color toner images. In addition, the cleaning performance with the cleaning blade is
Since the toner particles B are in a state of protruding from the outer surface of the endless intermediate transfer belt 7a as described above, the results are extremely good.

[0010] The intermediate transfer endless belt having the fine grooves 7b as described above is manufactured using, for example, the apparatus shown in FIG. That is, an intermediate transfer endless belt 7a extruded into a cylindrical shape using a thermoplastic resin molding material is placed approximately coaxially within a steel pipe 20 on which fine protrusions corresponding to the fine grooves 7b are distributed on the inner peripheral surface. The heat roll 21 is brought into contact with the heat roll 21, and the drive roll 22 is rotationally driven in this state.
By rotating the steel pipe 20, the belt 7a, and the heat roll 21, the outer circumferential surface of the intermediate transfer endless belt 7a is slightly melted and the minute convex stripes of the steel tube 20 are transferred, thereby forming fine lines on the outer circumferential surface of the belt 7a. Forming the groove 7b is performed. Further, it is also possible to use a normal roll instead of the heat roll 21, heat the intermediate transfer endless belt by blowing hot air, and form the fine grooves 7b in the same manner as described above.

FIG. 5 shows another form of forming the fine grooves 7b. In this embodiment, the fine grooves 7b are formed symmetrically with respect to the center line of the endless intermediate transfer belt 7a. The rest is the same as in FIG. 1. In this way, the fine groove 7b
As a result, the remaining toner is scraped off in the left and right directions by the cleaning blade, improving toner removal performance.

[0012] Next, the state of the copied image when the intermediate transfer endless belt of the above embodiment (FIG. 1) and the intermediate transfer endless belt of the comparative example are installed in the apparatus shown in FIG. 4 and copied is compared and shown. Shown in 1.

[0013]

[Table 1]

From the table above, it can be seen that the examples provide better images than the comparative examples.

[0015]

[Effects of the Invention] As described above, the intermediate transfer endless belt of the present invention has countless fine grooves distributed on the outer surface that are inclined with respect to the longitudinal direction of the belt, so that it can be used for a long period of time. However, the intermediate transfer endless belt does not loosen or rotate unevenly due to contact friction between the surface of the intermediate transfer endless belt and the cleaning blade, and therefore distortion and positional deviation occur in the toner image transferred from the photoreceptor. do not have. Moreover,
The remaining toner is also completely removed by the cleaning blade, and the image quality of the copied image does not deteriorate due to the remaining toner.

[Brief explanation of drawings]

FIG. 1 is a perspective view of an embodiment of the invention.

FIG. 2 is an explanatory diagram of a state in which toner particles are attached to the surface thereof.

FIG. 3 is an explanatory diagram of another state in which toner particles are attached.

4 is a manufacturing explanatory diagram of the intermediate transfer endless belt of FIG. 1. FIG.

FIG. 5 is a perspective view of another embodiment of the invention.

FIG. 6 is a configuration diagram of a copying machine incorporating the endless intermediate transfer belt of the present invention.

FIG. 7 is an enlarged cross-sectional view of the circled portion A in FIG. 6;

[Explanation of symbols]

7a　Intermediate transfer endless belt 7b Fine groove

Claims (3)

[Claims] Claim 1: The toner image of the photoreceptor transferred to the outer surface of the photoreceptor is retransferred onto the copy paper in the process of being stretched over a plurality of rollers and circulated, and the remaining toner particles are removed by a cleaning blade. What is claimed is: 1. An endless intermediate transfer belt, characterized in that numerous fine grooves are distributed and formed on the outer surface thereof, the grooves being inclined with respect to the longitudinal direction of the belt. 2. Claim 1, wherein the fine grooves are arranged at an angle such that 30°≦θ≦60°, and the depth of the grooves is set to 2/3 or less of the particle diameter of the toner particles. The intermediate transfer endless belt described. 3. The intermediate transfer endless belt according to claim 1, wherein the upper end edge of the groove wall of the fine groove is chamfered in a rounded shape.