KR100358339B1 - Method for disposing a surface of a doctor blade for developing device - Google Patents

Abstract

The present invention relates to a method for surface treatment of a doctor blade for a developing device. In the present invention, first, a first machining step of processing a surface of a doctor blade base material, which is expected to be in contact with a developing roller, using, for example, a planar grinding machine, is performed. Next, a secondary processing step of blastering the surface of the base material using a specific material such as sand or alumina powder as a grit is performed, and a chemical vapor deposition process such as a plasma chemical vapor deposition process is performed on the surface of the base material. Proceeding to the third step of forming a wear-resistant layer of a conductive material on the surface of the base material. At this time, the wear resistant layer finally formed on the surface of the base material is made of, for example, tungsten carbide.

When the present invention is achieved, the doctor blade can maintain a uniform surface roughness by the blaster treatment process, as well as maintain a certain level of wear resistance by the next wear-resistant layer forming process, The doctor blade, which is finally finished, can smoothly perform the "toner amount regulation role" given to it even when it is in contact with the developing roller for a long time. As the durability of the doctor blade is improved, the image finally formed on the recording paper can maintain excellent quality.

Description

Method for disposing a surface of a doctor blade for developing device}

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a doctor blade mounted as a major component of an image forming apparatus employing an electrophotography method, for example, a developing device provided in a laser printer, a pex, a copier, and more specifically, a doctor. The present invention relates to a method of treating a doctor blade for a developing device for achieving the "secure abrasion resistance", "the uniform surface roughness", etc. of the blade at once.

In general, an image forming apparatus employing an electrophotographic method, for example, a developing device included in a laser printer, a fax, a copying machine, or the like, generally includes a structure such as a photosensitive drum and a developing roller. After generating an electrostatic latent image on its outer circumferential surface, the toner is supplied to the electrostatic latent image through a developing roller disposed adjacent to the image, thereby developing the electrostatic latent image as a visible image, and onto the recording paper. Form an image.

The general structure of a developer for an image forming apparatus according to the related art is, for example, US Patent No. 5132734 "Developing apparatus", US Patent No. 5260748 "Electrostatic image developer dispenser" , U.S. Patent 5552870, "Developing device for an image forming apparatus," U.S. Patent No. 5771426, Developing device using a toner and carrier mixture. ), US Pat. No. 5787328, "Rotary developing device for an image forming apparatus."

At this time, the above developing roller is supplied with a predetermined amount of toner from the toner cartridge, and then rotates in engagement with the photosensitive drum so that the toner can be supplied to the photosensitive drum in this case. At the top, a regulating blade is arranged for regulating the thickness of the toner supplied to the photosensitive drum to a certain height. This regulating blade is usually called "doctor blade" in the production line.

The doctor blade is made of, for example, a rubber material or a metal material. For example, when the doctor blade is made of a rubber material, in the production line, the developing roller is maintained at a constant pressure using the elastic force of the doctor blade without a separate pressing means. The pressing process is performed, and as another example, when the doctor blade is made of a metal material, it is provided with a separate pressurizing means for pressing the developing roller, and the process of pressing the developing roller at a constant pressure through the pressing means.

Such doctor blades generally have a quality that depends on "how consistently the height of the accumulated toner on the developing roller can be regulated."

The general structure of a doctor blade according to the prior art is described in, for example, US Pat. No. 5085171, "Compliant doctor blade", US Pat. No. 5,233,390, "Electronic with a position roller of a magnetic roller and a doctor blade." Electronic printer developing unit with bracket for positioning magnetic roller and doctor blade, US Patent No. 5702812 "Compliant doctor blade", US Patent No. 5853868 "Electronic for flexible doctor blade" Electrical contact material for flexible doctor blade ”, and the like.

Since the doctor blade is generally in strong contact with the developing roller surface, it is common to receive strong contact force and frictional force from the developing roller for a long time, and in the production line, no action is taken on the contact surface between the doctor blade and the developing roller. If not, the doctor blade will be greatly abraded by the action of the above-described contact and frictional forces, thereby completely losing the developer regulating function assigned to it. In this case, since the roughness of the doctor blade is caused to be uneven, the image finally formed on the recording paper has no choice but to maintain low quality.

In view of such harsh conditions, in the conventional production line, when manufacturing a doctor blade, the contact surface of the doctor blade is physically treated, for example, in advance, so that the contact surface of the doctor blade may have a certain level of durability and wear resistance. have.

For example, in a conventional production line, a method of making a surface of a doctor blade in contact with a developing roller has a constant roughness by performing a blaster process in which sand is grit on the surface of a doctor blade. .

In another example, in the conventional production line, the thermal spray coating process is performed on the surface of the doctor blade to form a "tungsten / cobalt layer in which tungsten carbide and cobalt are mixed in a proportion" on the surface of the doctor blade, A method for improving the "roughness uniformity" and "wear resistance" is devised.

Subsequently, the doctor blade having completed the surface treatment comes into contact with the outer circumferential surface of the developing roller every time the toner is supplied from the toner supply tool, thereby regulating the thickness of the toner supplied to the photosensitive drum to a specific height, thereby forming an image on the recording paper. This leads to maintaining a certain level of quality.

However, there are some significant problems in operating such a conventional doctor blade.

As described above, in the conventional production line, efforts are being made in various ways so that the contact surface of the doctor blade may have a certain level of durability and wear resistance.

By the way, as part of this effort, when the above-described "sand grit brister process" proceeds, the doctor blade can maintain a certain level of roughness at the beginning of the process, but if the use is made for a long time, the development roller The frictional force of and causes wear of the surface, which in turn leads to a problem in that it is not possible to smoothly perform the "toner amount regulating role" given to it.

In addition, in the conventional production line, when the above-mentioned "spray coating process" is performed as another part of the effort to improve durability and wear resistance, the action of the "tungsten / cobalt layer" formed by the high-pressure physical impact Because of this, the roughness of the doctor blade becomes too rough, resulting in a problem that it becomes difficult to regulate the thickness of the toner to a constant height.

Furthermore, when the toner supplied to the rotary roller is used, "pulverized one-component toner", due to the surface roughness of the toner itself, the doctor blade is subjected to a stronger surface friction, and eventually, due to friction with the developing roller The large wear of the surface leads to the problem of being unable to perform the "toner amount regulatory role" given to it smoothly.

In order to prevent such a problem in advance, a method of uniformizing the surface roughness of the doctor blade and improving the wear resistance of the doctor blade should be developed at the same time. There is no way to deal with it.

Accordingly, it is an object of the present invention to equalize the surface roughness of the doctor blade to uniformize the height of the toner accumulated on the outer circumferential surface of the developing roller in an optimal state.

Another object of the present invention is to improve the abrasion resistance of the doctor blade in a state where the surface roughness of the doctor blade is uniform, so that the doctor blade does not wear even if it is in contact with the developing roller for a long time, and smoothly performs the "toner amount regulating role" given to it. To make it work.

Another object of the present invention is to allow the contact surface of the doctor blade to have a certain level of durability and wear resistance, so that the quality of the image finally formed on the recording paper can be improved to a certain level or more.

Still other objects of the present invention will become more apparent from the following detailed description and the accompanying drawings.

1 is a flow chart sequentially showing a surface treatment method of a doctor blade for a developer according to the present invention.

Figures 2a to 2c is an illustration showing each embodiment of the surface treatment method of the doctor blade for a developer according to the present invention.

Figure 3 is an illustration showing a developing device employing a doctor blade according to the present invention.

4 is an exemplary view showing a contact structure of a doctor blade and a developing roller according to the present invention.

In order to achieve the above object, in the present invention, the surface treatment process of the doctor plate is divided into several steps. In this case, the production line first proceeds with the primary processing step of processing the surface of the doctor blade base body, which is expected to be in contact with the developing roller, for example using a planar grinding machine, and then sand or alumina powder. Using the grit, the secondary processing step of blastering the surface of the base material is carried out, and the chemical vapor deposition process, for example, the plasma chemical vapor deposition process, is performed on the surface of the base material, and the surface of the base material is made of tungsten carbide. The third processing step to form a wear-resistant layer is carried out.

By the above-described grinding | polishing process of the planar grinding machine, the doctor blade base material which is expected to contact with a developing roller is polished with surface roughness of 1 micrometer or less, for example.

Subsequently, by the blasting process of the sand or alumina powder described above, the surface of the doctor blade base material has a specific surface roughness value. At this time, in the production line, the surface roughness value of the surface of the doctor blade base material can be adjusted in the final required dimension, for example, in the range of 1 μm to 10 μm, for example, the size of the grit, the distance between the air gun and the base material, Adjust the air pressure of the air gun.

Subsequently, by the progress of the chemical vapor deposition process, for example, the plasma chemical vapor deposition process, the surface of the base material receives a wear resistant layer of a conductive material, for example, a tungsten carbide layer. The tungsten carbide layer covers the "surface of the base material whose surface roughness value is adjusted to the final required dimension in the production line" by the above-described blaster treatment process, whereby the surface of the finished base material has a predetermined level or more. To induce wear resistance.

When the present invention is achieved, the doctor blade can maintain a uniform surface roughness by the blaster treatment process, as well as maintain a certain level of wear resistance by the next wear-resistant layer forming process, The doctor blade, which is finally finished, can smoothly perform the "toner amount regulation role" given to it even when it is in contact with the developing roller for a long time. As the durability of the doctor blade is improved, the image finally formed on the recording paper can maintain excellent quality.

Hereinafter, the surface treatment method of the doctor blade for a developer according to the present invention with reference to the accompanying drawings in more detail.

As shown in Figure 1, first, in the production line proceeds to the primary processing step of processing the doctor blade base material (step S1).

In this case, first, in the production line, a doctor blade base member having a bulk type is processed by using a processing apparatus to form a doctor blade base material having, for example, a rectangular parallelepiped base frame.

At this time, as the doctor blade base material, S45C or SCM4 is preferably used.

When the base frame of the doctor blade base material is completed through the above-described process, as shown in Figure 2a, in the production line, a certain surface of the doctor blade base material 7, for example, the surface is expected to contact the developing roller to be described later By rotating the planar grinding machine 20, the surface of the doctor blade base material 7 is polished to a constant roughness. In this case, in the production line, by adjusting the grinding force of the planar grinding machine 20, for example, the rotational speed of the planar grinding machine 20, the surface of the doctor blade base material 7 can be processed, for example, with roughness of 1 μm or less. do.

On the other hand, when all of the above-described primary processing is completed, the production line uses a specific material as a grit, and proceeds to the secondary processing of blastering the surface of the doctor blade base material 7 (step S2).

In this case, as shown in FIG. 2B, in the production line, the air gun 30 with the injection hole is exposed toward the surface of the doctor blade base material 7, and then inside the air gun 30 using the compression force of the compressor 31. The grit loaded therein is strongly sprayed onto the surface of the doctor blade base material 7.

At this time, for example, sand or alumina powder is used as the grit sprayed onto the surface of the doctor blade base material 7.

When all of the grit blaster treatment process is completed, the surface of the doctor blade base material 7 is finely broken by the blasting process of strongly sprayed sand or alumina powder, thereby having a specific surface roughness value. At this time, in the production line, various factors of the grit blaster treatment process are performed so that the roughness value of the surface of the doctor blade base material 7 can be adjusted within the final required dimension, for example, 1 μm to 10 μm, in the production line. For example, the size of the grit, the distance between the air gun and the base material, the air pressure of the air gun, and the like are adjusted.

On the other hand, when all of the above-described secondary processing is completed, the production line undergoes a chemical vapor deposition process, for example, a plasma chemical vapor deposition process, on the surface of the doctor blade base material 7, and thus the surface of the doctor blade base material 7. In the third process to form a wear-resistant layer of a conductive material in progress (step S3).

In this case, as shown in Fig. 2c, in the production line, the doctor blade base material 7 whose surface roughness value is uniformly adjusted through the above-described secondary processing is moved into the vacuum chamber 41, and then the doctor blade. The base material 7 is positioned above the electrostatic chuck 44 inside the vacuum chamber 41.

In this state, the production line supplies the deposition gas through the deposition gas supply line 42 and applies a high frequency current to the electrostatic chuck 44 that supports the doctor blade base material 7.

In this case, in the production line, the temperature of the inside of the vacuum chamber 41 is maintained at a predetermined temperature, for example, 100 ° C. to 150 ° C., such that the doctor blade base material 7 carried into the vacuum chamber 41 is damaged by thermal shock. Prevent in advance.

On the other hand, the deposition gas supplied through the above-described deposition gas supply line 42 is introduced into the vacuum chamber 41 through the gas nozzle of the distribution plate 43, and then activated and transferred to the plasma particle state, the As a result, heavy molecules and ions are generated in the vacuum chamber 41. These heavy molecules and ions are rapidly deposited on the surface of the doctor blade base material 7, so that the wear resistance of a certain thickness, for example, in the range of 1 μm to 2 μm on the surface of the doctor blade base material 7 as shown in the figure. Layer 7a is formed. In this case, the wear resistant layer 7a is made of, for example, tungsten carbide material.

Usually, tungsten carbide is known as a material having a strong mechanical strength, so that when the wear-resistant layer 7a having the tungsten carbide material covers the surface of the doctor blade base material 7 to a certain thickness, the doctor is finished with the final work. The blade base material 7 may have more than a certain level of wear resistance.

In short, the doctor blade base material 7 of the present invention can be uniformly adjusted to its "surface roughness value" to the final required dimension in the production line, through the above-described secondary processing process, Through the above-described third process, the wear resistance of the doctor can be greatly enhanced. Thus, the doctor blade, which is finally finished by the practice of the present invention, can maintain a uniform surface roughness and also have a certain level of wear resistance. I can keep it.

In this case, the doctor blade that is finally finished can smoothly perform the "toner amount regulation role" given to it even when it is in contact with the developing roller for a long time, and as the durability of the doctor blade is improved, it is finally formed on the recording paper. The image can maintain excellent quality.

On the other hand, as shown in Figure 3, in the developing device employing the doctor blade of the present invention, the photosensitive drum 1 that rotates at a constant speed is provided inside the developing frame 2, the photosensitive drum 1 is charged The roller 3 meshes with the roller 3 to form a rotating structure. At this time, the charging roller 3 serves to charge the surface of the photosensitive drum 1 to a high voltage.

Here, an exposure apparatus 4 is installed at a predetermined position of the photosensitive drum 1, for example, the upper part of the photosensitive drum 1, and the exposure apparatus 4 emits a predetermined amount of light to the photosensitive drum 1 charged by the charging roller 3 described above. By irradiating, it serves to expose the electrostatic afterimage formed on the photosensitive drum 1. In addition, a transfer roller 12 is provided below the strong drum 1, and the transfer roller 12 rotates in engagement with the photosensitive drum 1, thereby transferring the final formed image toward the recording paper fed from the outside. Do this.

At this time, as shown in the figure, the toner cartridge 10 is mounted on one side of the developer frame (2). The toner cartridge 10 is provided with an agitator 9 for stirring the loaded toner 5, in which case the agitator 9 stirs the toner 5 loaded in the toner cartridge 10 and stirs it. It serves to supply the completed toner 5 to the supply roller 8.

Here, the above-described photosensitive drum 1 is engaged with the developing roller 6 to rotate, and the developing roller 6 is engaged with the feeding roller 8 which receives the toner 5 from the stirrer 9 and rotates. To achieve the structure. At this time, the developing roller 6 serves to fix the toner 5 to the photosensitive drum 1 having the electrostatic residual image after receiving the toner 5 from the supply roller 8.

Here, the doctor blade base material 7 of the present invention is mounted on the developing roller 6 to regulate the thickness of the toner supplied to the photosensitive drum to a certain height. In this case, the doctor blade base material 7 has a structure in which one end thereof is fixed to the developer frame 2 via the bracket 50, and the other end forms a structure in contact with the outer circumferential surface of the developing roller 6. .

At this time, as shown in FIG. 4, the doctor blade base material 7 has a structure that is in strong contact with the outer circumferential surface of the developing roller 6, and receives a strong contact force and friction force from the developing roller 6 for a long time. If no action is taken on the doctor blade base material 7 of this structure, the doctor blade base material 7 wears the surface due to the frictional force with the developing roller 6, and eventually, the "toner amount regulating role" given to it. This causes problems that can't be done smoothly.

In view of this, in the present invention, as described above, the surface of the doctor blade base material 7 in contact with the developing roller 6 is uniformly roughened, for example, by advancing the brister process using sand or alumina powder as a grit. To have the desired final roughness on the production line. In addition, in the present invention, by performing a chemical vapor deposition process using a plasma, as shown in the drawing, on the surface of the doctor blade base material 7 in which the roughness is uniformly adjusted in advance, the wear-resistant layer 7a is formed, Through this, the wear resistance of the doctor blade base material 7 is enhanced.

When the present invention is achieved, in the production line, it is possible to obtain the effect that the "surface roughness uniformity" and "enhanced wear resistance" of the doctor blade base material 7 are simultaneously achieved, and eventually the doctor is in contact with the developing roller 6. The blade base material 7 can uniformize the height of the toner accumulated on the outer circumferential surface of the developing roller 6 to an optimum state, and can withstand contact for a long time without any "wear phenomenon" even when contacted with the developing roller 6, This provides an effect of improving the quality of the image finally formed on the recording paper to a certain level or more.

Thereafter, the doctor blade base material 7 of the present invention comes into contact with the outer circumferential surface of the developing roller 6 whenever the toner 5 is supplied from the developing roller 6, and is supplied to the photosensitive drum 1. By regulating the thickness of the film to a specific height, an image of good quality can be formed on the recording sheet.

As described above, in the present invention, in the state where the surface roughness of the doctor blade is uniform, the wear resistance of the doctor blade is greatly improved, so that even when the doctor blade is in contact with the developing roller for a long time, it is not worn out and the " toner amount regulation given thereto is given. Role "can be induced to perform smoothly.

The present invention has an overall useful effect in various types of image forming apparatuses produced in a manufacturing line.

And while certain embodiments of the invention have been described and illustrated, it will be apparent that the invention may be embodied in various modifications by those skilled in the art.

Such modified embodiments should not be understood individually from the technical spirit or point of view of the present invention and such modified embodiments should fall within the scope of the appended claims of the present invention.

As described in detail above, in the method for surface treatment of a doctor blade for a developer according to the present invention, first, a primary processing step of processing a surface of a doctor blade base material, which is expected to be in contact with a developing roller, using, for example, a planar grinding machine, is performed. And then a secondary processing step of blastering the surface of the base material using a specific material such as sand or alumina powder as the grit, followed by a chemical vapor deposition process such as a plasma chemical vapor phase. The deposition process is performed, and a third processing step of forming a wear resistant layer of a conductive material on the surface of the base material is performed. At this time, the wear resistant layer finally formed on the surface of the base material is made of, for example, tungsten carbide.

When the present invention is achieved, the doctor blade can maintain a uniform surface roughness by the blaster treatment process, as well as maintain a certain level of wear resistance by the next wear-resistant layer forming process, The doctor blade, which is finally finished, can smoothly perform the "toner amount regulation role" given to it even when it is in contact with the developing roller for a long time. As the durability of the doctor blade is improved, the image finally formed on the recording paper can maintain excellent quality.

Claims (10)

A first processing step of processing a surface of a base body on which contact with a developing roller is expected; A secondary processing step of blastering the surface of the base material using any one of sand or alumina powder as a grit; And a tertiary processing step of performing a chemical vapor deposition process on the surface of the base material to form a conductive wear-resistant layer of tungsten carbide on the surface of the base material. The surface treatment method of a doctor blade for a developing device according to claim 1, wherein the base material is made of any one material of S45C or SCM4. The surface treatment method of a doctor blade for a developing device according to claim 2, wherein the surface of the base material is processed at roughness of 1 탆 or less when the primary processing step is performed. The method of claim 1, wherein when the secondary processing step is performed, the surface of the base material is processed to a target final surface roughness dimension. The surface treatment method of a doctor blade for a developing device according to claim 4, wherein the surface roughness of the surface of the base material has a dimension of 1 µm to 10 µm when the secondary processing step is performed. delete The method of claim 1, wherein the chemical vapor deposition process in the tertiary processing step is a plasma chemical vapor deposition process. 8. The method of claim 7, wherein the plasma chemical vapor deposition process is performed in a temperature range of 100 ° C to 150 ° C. The method of claim 1, wherein the wear-resistant layer is made of tungsten carbide. 10. The method of claim 9, wherein the wear-resistant layer is formed to a thickness of 1㎛ ~ 2㎛ Doctor treatment blades for the developer.