JP2021033050A - Cleaning blade and image forming apparatus - Google Patents

Abstract

To provide a cleaning blade that removes a foreign substance, such as toner remaining on a belt-like image carrier, and an image forming apparatus.SOLUTION: A cleaning blade 24 is brought into contact with a belt-like image carrier 17 to clean a surface of the belt-like image carrier 17, and the cleaning blade 24 is formed of a conductive thin plate. A leading end 24d brought into contact with the belt-like image carrier 17 has a plurality of projections (24a, 24b, 24c), and of the plurality of projections, one projection 24a projects beyond the other projections 24b and 24c.SELECTED DRAWING: Figure 3

Description

The present invention relates to a cleaning blade and an image forming apparatus.

The electrostatic image formed on the surface of the photoconductor drum is developed with toner to form a toner image, and the toner image is transferred to a belt-shaped image carrier (also called an intermediate transfer belt) and placed on the intermediate transfer belt. An image forming apparatus for transferring the formed toner image to paper is known. Such an image forming apparatus is provided with a cleaning apparatus for cleaning the toner remaining on the intermediate transfer belt.
As a cleaning device, for example, Patent Document 1 discloses a device including a rigid blade made of metal. The rigid blade described in Patent Document 1 has a rounded shape with a radius of curvature smaller than the average particle size of the toner particles upstream of the moving direction of the image carrier on a metal base material.

JP-A-2017-203828

In recent years, improving the performance of a cleaning blade that cleans foreign matter such as toner remaining on a belt-shaped image carrier is important for forming a high-quality image.
The present invention has been made in view of the above circumstances, and provides a cleaning blade that satisfactorily removes foreign substances such as toner remaining on a belt-shaped image carrier, and an image forming apparatus capable of providing a high-quality image. The purpose is to do.

As a result of diligent studies, the present inventor has found that the above problems can be solved by shaping the tip of the blade into a specific shape, and has arrived at the present invention.
That is, the present invention is a cleaning blade that is in contact with the belt-shaped image carrier and cleans the surface of the belt-shaped image carrier, and is made of a conductive thin plate and has a tip portion that is in contact with the belt-shaped image carrier. A cleaning blade having a plurality of convex portions, of which one convex portion protrudes from the other convex portions.

The number of convex portions is preferably three.

It is preferable that one convex portion is located in the center.

The height difference between the tip of one convex portion and the tip of the other convex portion is preferably 5 μm or more and 15 μm or less.

The cleaning blade is preferably made of stainless steel, hardened steel or flat steel.

The distance between the plurality of protrusions is preferably 5 μm or more and 25 μm or less.

The thickness of the cleaning blade is preferably 70 μm or more and 120 μm or less.

The cleaning blade may be one that charges the surface of the belt-shaped image carrier by applying a voltage.

The image forming apparatus of the present invention includes the cleaning blade of the present invention.

According to the cleaning blade of the present invention, foreign matter such as toner remaining on the belt-shaped image carrier can be satisfactorily removed.
Further, according to the image forming apparatus of the present invention, a high quality image can be obtained.

It is the schematic sectional drawing which shows one Embodiment of the image forming apparatus of this invention. It is a top view of the cleaning blade. It is the schematic cross-sectional view which shows the contact state between a cleaning blade and a belt-shaped image carrier. It is sectional drawing of the tip part of a cleaning blade.

Hereinafter, the present invention will be described with reference to the drawings.
[Image forming device]
An embodiment of the electrophotographic image forming apparatus of the present invention will be described. The image forming apparatus of the present embodiment includes the cleaning blade of the present invention.
The image forming apparatus 10 mounts a plurality of photoconductor drums 12B, 12C, 12M and 12Y mounted on the developing units 11B, 11C, 11M and 11Y of each color (black, cyan, magenta, yellow) on the belt-shaped image carrier 17. It is a tandem type color image forming apparatus arranged in series with.
Each developing unit 11B, 11C, 11M and 11Y contains a one-component non-magnetic black developing agent, a cyan developing agent, a magenta developing agent and a yellow developing agent, respectively.

Electrostatic latent images on the surfaces of the photoconductor drums 12B, 12C, 12M and 12Y charged by the charging means 14B, 14C, 14M and 14Y in the developing units 11B, 11C, 11M and 11Y Is formed, and a black electrostatic latent image is developed with the toner supplied by the toner supply rollers 16B, 16C, 16M and 16Y. The developed black toner image, cyan toner image, magenta toner image, and yellow toner image are sequentially transferred onto the belt-shaped image carrier 17 by the primary transfer rollers 15B, 15C, 15M, and 15Y, and the color toner is transferred. An image is formed.

The color toner image formed on the belt-shaped image carrier 17 is applied with a voltage by the secondary transfer rollers 18 and 19 and transferred to the paper 27 delivered from the paper feed unit 26. After that, the color toner image transferred to the paper 27 is melted by the pressure roller 21 and the fixing roller 22 in the fixing means 20 and fixed on the paper 27.

The belt-shaped image carrier 17 is an endless belt made of polyimide, polyamide-imide, polycarbonate, polyamide, acrylonitrile-butadiene copolymer (NBR), chloroprene rubber (CR), etc., and circulates in the direction of the arrow in FIG. To do.
After the color toner image on the belt-shaped image carrier 17 is transferred to the paper 27, foreign substances such as toner remaining on the belt-shaped image carrier 17 are removed by the cleaning blade 24 of the cleaning device 23.
Since the image forming apparatus of the present invention includes the cleaning blade 24 of the present invention, the toner remaining on the surface of the belt-shaped image carrier 17 is satisfactorily removed, so that a high-quality image can be obtained.

[Cleaning blade]
Next, the cleaning blade 24 of the cleaning device 23 in this embodiment will be described.
As shown in FIGS. 2 and 3, the cleaning device 23 supports the cleaning blade 24 and the cleaning blade 24, which are made of a conductive thin plate that is brought into contact with the belt-shaped image carrier 17 and cleans the belt-shaped image carrier 17. Has a body 25 and. The cleaning blade 24 is arranged so that its tip portion 24d is in contact with the belt-shaped image carrier 17 in a range of an angle (θ) of 10 ° or more and 90 ° or less.

As shown in FIG. 3, the cleaning blade 24 is arranged in the longitudinal direction at right angles to the circumferential direction of the belt-shaped image carrier 17. Further, as shown in FIGS. 3 and 4, the cleaning blade 24 of the present embodiment has three convex portions 24a, 24b and 24c at the tip portion 24d that abuts on the belt-shaped image carrier 17. Of the three convex portions, the convex portion 24a located at the center protrudes from any of the convex portions 24b and 24c at both ends. Since the cleaning blade 24 is provided on the belt-shaped image carrier 17 at an angle, at least two points, the most protruding convex portion 24a and the downstream convex portion 24c, come into contact with the belt-shaped image carrier 17. ing.
The pressure at which the cleaning blade 24 comes into contact with the belt-shaped image carrier 17 is preferably adjusted appropriately depending on the material of the belt-shaped image carrier 17, the number of convex portions at the tip of the cleaning blade 24, and the contact angle.

The cleaning blade 24 of the present invention has a higher effect of removing foreign substances such as toner than the conventional cleaning blade having a rectangular tip portion without a convex portion. Although the details are unknown, it is presumed that the protruding thin convex portion of the cleaning blade 24 allows the toner to be satisfactorily removed between the belt-shaped image carrier 17 and the tip of the cleaning blade 24 without being crushed.
Further, depending on the contact angle and pressure of the cleaning blade 24, at least two convex portions (24a and 24c) are in contact with the surface of the belt-shaped image carrier 17, and thus cannot be completely removed by the first convex portion 24a. It is also presumed that foreign matter such as toner is removed by the convex portion 24c on the downstream side.

_{As shown in FIG. 4, the difference h 24} between the tip of the convex portion 24a in the center and the tips of the convex portions 24b and 24c on both sides is 5 μm or more from the viewpoint of removability of foreign matter such as toner and workability of the convex portion. It is preferably 15 μm or less, and more preferably 6 μm or more and 10 μm or less.
Here, when there are two or more convex portions other than the most protruding convex portion, the difference h ₂₄ indicates the difference between the other convex portion and the most protruding convex portion, and the respective differences are different. Both indicate that they are within the above numerical range.

The thickness T ₂₄ (see FIG. 4) of the cleaning blade 24 is preferably 70 μm or more and 120 μm or less. When it is 70 μm or more, sufficient strength as a cleaning blade can be obtained, and the convex portion can be easily processed. Further, when the thickness is 120 μm or less, the plurality of convex portions are likely to come into contact with the belt-shaped image carrier 17, and the belt-shaped image carrier 17 can be prevented from being damaged.

_{The distance P 24} between the convex portions is preferably 10 μm or more and 30 μm or less from the viewpoint of the material of the cleaning blade and the workability of the convex portions.
Further, the distance P ₂₄ between the convex portions is preferably larger than the average particle size of the toner constituting the toner image. Usually, the average particle size of the toner used in the electrophotographic image forming apparatus is in the range of about 2 μm or more and 10 μm or less. Since the distance P ₂₄ between the convex portions is larger than the average particle size of the toner constituting the toner image, foreign matter such as toner removed by the most protruding convex portions 24a enters the concave portions between the convex portions. It is presumed that it is possible to prevent the tip portion 24d from being crushed at another portion and adhering to the surface of the belt-shaped image carrier 17 or the tip portion 24d.
Further, when the cleaning blade 24 is provided with the voltage applying means described later and a potential opposite to that of the toner is applied, the toner is accommodated in the recess and does not adhere to the belt-shaped image carrier 17 again. , The removal effect is expected to be improved.

In the above embodiment, the case where the convex portion is three is described, but it may be two or four or more. From the viewpoint of foreign matter removability and workability of the convex portion, two and three are preferable, and three are most preferable. Further, in the above embodiment, the most protruding convex portion is arranged in the center, but the present invention is not limited to the center and may be an end. When there are four or more protrusions, it may be other than the center and the edges.

The convex portion of the cleaning blade 24 can be formed by deep digging RIE (reactive ion etching) by providing a mask at a position corresponding to the convex portion. Deep-drilled RIE includes etching using high-density plasma (ICP-RIE) and etching using microwaves (ECR-RIE).

The length _{L 24} of the cleaning blade 24 (see FIG. 2) is, depending on the width of the belt-shaped image carrier 17 is preferably 20cm or 40cm or less.

The cleaning blade 24 is preferably made of a metal such as SUS (stainless steel rigid), hardened steel, or flat steel with high hardness from the viewpoint of durability and workability.

The cleaning blade 24 may include a voltage applying means (not shown). By applying a potential opposite to that of the toner to the cleaning blade 24 by the voltage applying means, the surface of the belt-shaped image carrier 17 is charged with the opposite charge to the toner. As a result, the remaining foreign matter such as toner can be electrically attracted to the cleaning blade 24, so that the foreign matter removability is further improved.

As described above, the cleaning blade of the present invention has a plurality of convex portions at the tip, and one of the plurality of convex portions protrudes from the other convex portion, so that the cleaning blade can be used as a belt-shaped image carrier. Foreign matter such as toner can be satisfactorily removed when used in contact with each other.
Further, in the image forming apparatus provided with such a cleaning blade, foreign matter such as toner is satisfactorily removed from the belt-shaped image carrier, so that a high-quality image can be obtained.

10 Image forming apparatus 11B, 11C, 11M, 11Y Development unit 12B, 12C, 12M, 12Y Photoreceptor drum 13B, 13C, 13M, 13Y Exposure means 14B, 14C, 14M, 14Y Charging means 15B, 15C, 15M, 15Y Primary transfer Rollers 16B, 16C, 16M, 16Y Toner supply rollers 17 Belt-shaped image carriers 18, 19 Secondary transfer rollers 20 Fixing means 21 Pressurizing rollers 22 Fixing rollers 23 Cleaning equipment 24 Cleaning blades 25 Supports 24a, 24b, 24c Convex parts 24d Tip 25 Support 26 Feeder 27 Paper

Claims (9)

A cleaning blade that comes into contact with the belt-shaped image carrier and cleans the surface of the belt-shaped image carrier.
Consists of conductive sheet steel
A cleaning blade in which a tip portion abutting on the belt-shaped image carrier has a plurality of convex portions, and one of the plurality of convex portions protrudes from the other convex portion. The cleaning blade according to claim 1, wherein the convex portion has three. The cleaning blade according to claim 2, wherein the one convex portion is located at the center. The cleaning blade according to claim 1 to 3, wherein the difference in height between the tip of the one convex portion and the tip of the other convex portion is 5 μm or more and 15 μm or less. The cleaning blade according to any one of claims 1 to 4, wherein the cleaning blade is made of stainless rigid, hardened steel or flat steel. The cleaning blade according to any one of claims 1 to 5, wherein the distance between the plurality of convex portions is 5 μm or more and 25 μm or less. The cleaning blade according to any one of claims 1 to 6, wherein the thickness of the cleaning blade is 70 μm or more and 120 μm or less. The cleaning blade according to any one of claims 1 to 7, wherein the cleaning blade charges the surface of the belt-shaped image carrier by applying a voltage. An image forming apparatus including the cleaning blade according to any one of claims 1 to 8.

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