JPS61230182A - Cleaning blade for electrophotographic copying machine - Google Patents

Abstract

PURPOSE:To easily clean a photosensitive body for a long period by making one of two thickness-directional layers of a cleaning blade smaller in hardness than the other and using the low-hardness layer for the side of a photosensitive body. CONSTITUTION:The cleaning blade 1a is formed of two layers in its thickness direction; one layer 3 is formed of a material having smaller hardness than the other and the other layer 4 is formed of a material with larger hardness. Then, the layer 3 is used for the side of the photosensitive body 2 to remove toner from the surface of a photosensitive drum by the layer 3, so that the photosensitive body 2 is never damaged. The layer 4 adjoining to the layer 3 backs up the layer 3 and prevented the wear of the photosensitive body 2 from being accelerated. Consequently, the blade 1a neither curves nor deforms permanently and is pressed against the photosensitive body 2 with constant pressure, thereby cleaning the photosensitive body easily for a long period.

Description

DETAILED DESCRIPTION OF THE INVENTION [Background and Objects of the Invention] The present invention relates to a cleaning blade for an electrophotographic copying machine.

FIG. 1 shows a conventional example of a cleaning blade for an electrophotographic copying machine. As shown in FIG. 2, the conventional cleaning blade 1 is made of a single material (mainly urethane rubber) and is formed into a plate shape. drum) 2,
It is used to remove residual toner remaining on the photoreceptor 2.

That is, the cleaning blade 1 remains on the photoreceptor 2,
In order to remove toner from the photoreceptor 2 that causes stains, ghosts, etc. during the next copying, a precisely cut edge portion is brought into contact with the photoreceptor 2 while applying weak pressure. If a portion of the cleaning blade 1 becomes unable to remove toner from the surface of the photoconductor 2, problems such as the above-mentioned stains and ghosts will occur, and the so-called poor cleaning, in which the cleaning blade of the photoconductor 2 is not performed sufficiently, may occur. become. There are two reasons why the cleaning blade 1 is unable to remove toner from the surface of the photoreceptor 2, as described below. One of the problems is that the edge portion of the cleaning blade 1 that comes into contact with the photoreceptor 2 is chipped by foreign matter, paper dust, etc., and toner is allowed to pass through the chipped portion. Another problem is that since pressure is applied to the photoconductor 2, the strain applied to the cleaning blade 1 causes stress relaxation due to the effects of heat, etc., and pressure can no longer be applied to the photoconductor 2. .

Various attempts have been made to counter these problems, but with regard to the effects of paper dust, foreign matter, etc., if a material that is resistant to foreign matter, paper dust, etc., for example has a high hardness, is used, it may damage the photoreceptor 2 itself, making it more fatal. Therefore, using a material with high hardness is not an effective means. In addition, countermeasures have been taken to relieve the stress of the strain applied to the cleaning blade 1, such as applying a metal plate as a backup, but if the backup is too strong, it may accelerate wear of the photoreceptor 2 or damage the crystal structure of the photoreceptor 2. Using a metal plate as a backup is not an effective method. Also, a mechanism has been put into practical use in which the cleaning blade 1 is separated from the surface of the photoreceptor 2 when the machine is stopped under constant pressure, but the device is complicated and the cost increases significantly.

The present invention has been made in view of the above points, and an object of the present invention is to provide a cleaning blade for an electrophotographic copying machine that makes it possible to easily clean a photoreceptor over a long period of time.

[Summary of the Invention] That is, the present invention presses the edge portion of a photoreceptor of an electrophotographic copying machine, and removes residual toner on the photoreceptor.

In the cleaning blade of an electrophotographic copying machine, the cleaning blade has two layers in the thickness direction, one side of which is formed of a low hardness layer made of a material with a lower hardness than the other side. , the other side is formed of a high hardness layer made of a material having a harder hardness than that of the one side, and the layer of the low hardness portion is used with the layer facing the photoreceptor. As a result, the cleaning blade is formed with two layers, a low hardness layer and a high hardness layer, and is used with the low hardness layer facing the photoreceptor. It becomes like this.

[Example] The present invention will be described below based on the illustrated example. FIG. 3 shows an embodiment of the invention. Note that parts that are the same as those in the conventional system are given the same reference numerals, and therefore their explanations will be omitted. In this embodiment, the cleaning blade 1a has two layers in the thickness direction, one side of which is formed of a layer 3 of a low hardness portion made of a material with a lower hardness than the other side, and the other side of the cleaning blade 1a. It is formed with a layer 4 of a high hardness portion made of a material with a higher hardness. This was then used with the low hardness layer 3 facing the photoreceptor 2 as shown in FIGS. 4 and 5. By doing so, the cleaning blade 1a is formed with two layers, the layer 3 of the low hardness portion and the layer 4 of the high hardness portion, and is used with the layer 3 of the low hardness portion facing the photoreceptor 2. As a result, it is possible to obtain a cleaning blade 1a for an electrophotographic copying machine that makes it possible to easily clean the photoreceptor 2 over a long period of time.

That is, although the cleaning blade 1a is formed with the layer 3 of the low hardness portion and the layer 4 of the high hardness portion, the layer 4 of the high hardness portion
uses relatively high hardness (90 to 95 hardness) urethane rubber that is resistant to heat and moist heat deterioration.
has relatively low hardness with little wear (hardness is 70 to 7
5) Urethane rubber was used. By doing this, the residual toner on the surface of the photosensitive drum, which is the surface of the photoconductor 2, is removed by the layer 3 of the low hardness part, but since the part from which the residual toner is removed is the layer 3 of the low hardness part, Even if this is pressed against the photoreceptor 2, the photoreceptor 2 will not be damaged. Incidentally, the photoreceptor 2 is generally made of selenium, cadmium sulfide coated with a resin on the surface, or an organic photoreceptor that has a low surface hardness and is soft, but the layer 3 in the low hardness part is made of urethane rubber with a low hardness as described above. Since the photoreceptor 2 is used, the photoreceptor 2 will not be damaged even if the layer 3 of the low hardness portion is pressed against the layer 3. Since the layer 4 of the high hardness part is provided adjacent to the layer 3 of the low hardness part, the layer 3 of the low hardness part is backed up by the layer 4 of the high hardness part. layer 4
As mentioned above, since it is made of high hardness urethane rubber, it does not accelerate the wear of the photoreceptor 2 unlike when it is backed up with a metal plate. In this way, according to this embodiment, the cleaning blade 1a is no longer warped or permanently deformed, and is always pressed against the photoreceptor 2 with a constant pressure.
It is possible to clean the photoreceptor 2 over a long period of time. Also, since it can be made into a two-layer structure like this,
Cleaning blade 1 always at a constant pressure when the machine is stopped
There is no need to provide a mechanism for separating a from the photoreceptor surface, and the cleaning blade of the photoreceptor 2 can be easily cleaned over a long period of time.

As shown in FIG. 4, the leaning blade 1a is often installed facing the rotational direction of the photoreceptor 2 (photosensitive drum) indicated by the arrow in the figure. As shown in FIG. 5, it is often attached along the rotational direction of the photosensitive member 2 (photosensitive drum) indicated by the arrow in the figure. In this case, it is necessary that the pressing force on the photoreceptor 2 does not particularly decrease compared to the case shown in FIG. 4, but according to this embodiment, the pressing force of the cleaning blade 1a on the photoreceptor 2 can be maintained well for a long period of time. Therefore, the pressing force does not decrease.

Furthermore, in this example, the layer 3 of the low hardness part and the layer 4 of the high hardness part are formed of liquid urethane rubber that has good wear resistance and is made by a casting method. It is also possible to bond them together to form one body, or to mold them into one body by centrifugal molding.

In addition to urethane, resin materials with appropriate hardness, such as thermoplastic urethane and nylon, are used as materials.
Also used are fluororubber and silicone rubber, which have excellent heat resistance, or heat-effect resins, which are resistant to deformation due to heat or wet heat. Depending on the bonding method, it is also possible to use the two different materials mentioned above depending on the characteristics of the materials.

[Effect of R-light] As described above, the present invention provides a cleaning blade for an electrophotographic copying machine that makes it possible to easily clean a photoreceptor over a long period of time. Obtainable.

[Brief explanation of drawings]

FIG. 1 is a perspective view of a cleaning blade of a conventional electrophotographic copying machine, FIG. 2 is a side view showing how the cleaning blade of a conventional electrophotographic copying machine is used, and FIG. 3 is a perspective view of a cleaning blade of a conventional electrophotographic copying machine. A perspective view of one embodiment of the cleaning blade, and FIGS. 4 and 5 are side views showing different usage states of the cleaning blade of the electrophotographic copying machine of the present invention. 1a...Cleaning blade, 2...Photoreceptor, 3...Low hardness layer, 4...High hardness layer.

Claims (2)

[Claims] (1) In a cleaning blade for an electrophotographic copying machine that presses its edge against a photoconductor of the electrophotographic copying machine to remove residual toner on the photoconductor, the cleaning blade has two layers in the thickness direction. , one side of which is formed of a layer of a low hardness part made of a material with a harder hardness than that of the other side, and the other side is formed of a layer of a high hardness part made of a material with a harderness than that of the one side. A cleaning blade for an electrophotographic copying machine, characterized in that the cleaning blade is used with the layer of the low hardness portion facing the photoreceptor. (2) The cleaning blade for an electrophotographic copying machine according to claim 1, wherein the material with low hardness and the material with high hardness are urethane rubber.