JPH06202447A - Cleaning member for electrostatic charging device and process cartridge provided therewith - Google Patents

Abstract

PURPOSE:To prevent a defective image because of that unnecessary toner adheres to a photosensitive drum from an electrostatic charging roller so as to intercept exposing light for the photosensitive drum from occurring. CONSTITUTION:The electrostatic charging roller 2 is brought into contact with the photosensitive drum 1, and a cleaning member 3 is allowed to abut on the roller 2. The cleaning member 3 is constituted by sticking a sheet layer 3b to a base substance 3a such as sponge, etc., with a double-sided adhesive tape 3d. The sheet layer 3b is formed from a film-like polyethylene terephthalate, for example, and is triboelectrified to be negative when it rubs the roller 2. The toner T1 hardly adheres to the sheet layer 3b because the sheet layer 3b has the positive polarity which is the same as the toner T1 even when the negatively electrostatically charged toner T1 adheres to the roller 2 from the drum 1 and further, even if it tries to adhere to the sheet layer 3b. Thus, a situation that the toner is accumulated between the roller 2 and the sheet layer 3b and drops and adheres to the drum 1, is prevented.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a contact type charging device for contacting and charging a photoconductor such as an electrophotographic device.
Specifically, the present invention relates to a cleaning member for cleaning the charging member and a process cartridge including the cleaning member.

[0002]

2. Description of the Related Art Conventionally, in most cases, a charging process in an electrophotographic process using an electrophotographic photoconductor applies a high voltage (DC 5 to 8 kV) to a metal wire, and corona discharge generated at this time causes a surface of the photoconductor Is being charged. However, according to this method, along with the corona discharge the corona products such as ozone and NO _X occurs, or allowed to proceed deterioration and image quality blurred by alteration of the photosensitive member surface, based charging failure soil the metal wire There is a problem that the image quality is deteriorated, so-called white spots or black streaks are generated. Further, even in terms of electric power, the current effectively used to charge the photoconductor is only 5% to 30% of the whole, and most of it is in the shield plate surrounding the metal wire. It flowed, and was inefficient as a charging device.

In order to make up for such drawbacks, a contact charging method has been studied in which a charging member is brought into contact with a photosensitive member as a member to be charged, and a voltage is externally applied to the charging member to charge the photosensitive member. (For example, JP-A-57-57
178267, JP-A-56-104351, JP-A-58-40566, and JP-A-58-13.
9156, JP-A-58-150975, etc.).

As the charging member used in these contact charging methods, an elastic body such as a conductive rubber is generally used so that the contact with the photosensitive member is uniform. Further, the volume resistance of the charging member is set to about 10 ⁵ to 10 ¹⁰ Ω · cm in order to prevent charging failure when the photoconductor has a pinhole or the like.

By the way, it is known that such a conductive rubber generally undergoes large environmental fluctuations in resistance. Therefore, for example, even a material that can be normally charged in an environment of normal temperature and humidity has a possibility that the volume resistance increases and a charging failure may occur in an environment of low temperature and low humidity.

As a method of controlling the voltage applied to the charging member in order to solve such a problem, a method of controlling the alternating current component with a constant current is already known. That is, the resistance variation of the charging member due to the environment is canceled by the constant current control so that a constant voltage is always applied to the photoconductor.

However, even when such a control method is used, the following problems still remain unsolved.

The volume resistance of the charging member gradually increases as the number of printed sheets increases. Therefore, even with charging members that had no problems in all environments in the initial state,
Abnormal charging or poor charging may occur during repeated printing.In order to avoid this, it is necessary to set the volume resistance value in the initial state in anticipation of an increase in resistance due to repeated printing. The range of the resistance value of the charging member is narrowed, resulting in poor manufacturing efficiency.

One of the causes of such an increase in resistance is contamination of the charging member due to repeated printing. This is because fine powder of toner that has slipped through the cleaner adheres to the surface of the charging member, especially to the thin portion of the rubber layer due to the uneven thickness of the rubber layer in the axial direction during the manufacturing of the charging member, that is, where it floats from the surface of the photoreceptor. This is to partially increase the apparent volume resistance. Therefore, if a mechanism for cleaning the charging member is provided, dirt on the charging member can be removed and an increase in resistance can be suppressed. In fact, several such mechanisms have been devised.

[0010]

The problem to be solved by the invention will now be described with reference to FIG.
The problems of the conventional cleaning member will be described.

A charging roller (charging member) 2 is arranged in contact with a photosensitive drum 1 as a member to be charged, and a cleaning member 3 is in contact with the charging roller 2 with an appropriate pressing force. The charging roller 2 includes a cored bar 2a and a charging section 2b surrounding the cored bar 2a. The cleaning member 3 is formed of a sponge member such as urethane and is fixed to a cleaner sheet metal 5b that supports the blade tip 5a of the cleaning blade 5. The charging roller 2 is
A bias is applied by the external power supply 7 via the metal contact 6, and the photosensitive drum 1 is driven to rotate in the direction of arrow R2 as the photosensitive drum 1 rotates in the direction of arrow R1. by this,
The photosensitive drum 1 is charged to a predetermined potential.

On the charged photosensitive drum 1, an electrostatic latent image is formed by being exposed by the exposing means 9, and the electrostatic latent image is a toner image with toner attached by the developing sleeve 10a of the developing device. . The toner image on the photosensitive drum 1 is transferred onto the transfer material P by the transfer roller 11 and then fixed as a permanent image by a fixing device (not shown).

On the other hand, in the photosensitive drum 1 from which the toner image has disappeared due to the transfer, the residual toner remaining on the photosensitive drum 1 without being transferred is removed by the cleaning blade 5 and used for the next image formation.

Here, the toner that has passed through the cleaning blade 5 and further adhered to the fixing roller 2 is scraped off from the surface of the charging roller 2 by the cleaning member 3. However, in such a method in which the sponge-like cleaning member 3 is brought into contact with the charging roller 2 for cleaning, as the number of prints progresses,
Streaky toner sticking occurs in the circumferential direction on the surface of the charging roller 2.

The state is shown in FIG. The annular streak F1 formed on the surface of the charging roller 2 corresponds to the portion where the cleaning member 3 is in strong contact, and the toner sandwiched between the charging roller 2 and the cleaning member 3 is on the surface of the charging roller 2. It was made by sticking. Since the resistance of the streak F1 is higher than the resistance of other portions, for example, when a halftone image is printed in a low temperature and low humidity environment, a black streak-shaped charging failure indicated by F2 in FIG. Images may occur.

Further, when the charging roller 2 having such toner sticking is reused, the toner sticking must be completely removed, and there is a drawback that the recycling cost becomes high.

Further, since a soft sponge-like member is attached as the cleaning member 3, there is a problem that the positional accuracy is difficult to be obtained and the manufacturing yield is deteriorated.

In addition to the above-mentioned methods, proposals have been made, for example, to provide an electrode for cleaning, but all of them are not suitable for practical use because of high cost.

Further, in FIG. 6, in order to bring the cleaning member 3 into contact with the charging roller 2 in the axial direction accurately and uniformly,
An example is shown in which a nylon sheet layer 3b is provided on the surface of a conventional cleaning member (base) 3a. In addition, 3 in the figure
c and 3d are double-sided tapes for fixing the base body 3a to the cleaner sheet metal 5b, respectively, and the sheet layer 3b is the base body 3a.
It is a double-sided tape for fixing to.

When natural rubber is selected as the material of the charging roller 2 in such a structure, the following problems occur. When the charging roller 2 and the sheet layer 3b of the cleaning member 3 rub against each other, they are triboelectrically charged, but the charging polarity at this time is negative for the charging roller 2 and positive for the sheet layer 3b. As a result, the negative polarity toner T1 that has slipped through the cleaning blade 5 adheres to the charging roller 2 and then easily adheres to the opposite polarity sheet layer 3b, and a toner pool as indicated by T2 occurs.
Then, the toner T3 leaking from the toner T3 drops onto the photosensitive drum 1 and adheres to the photosensitive drum 1, blocking the laser light from reaching the surface of the photosensitive drum 1 during the exposure immediately after charging, and thus the electrostatic latent image. Was not formed well, and an abnormality occurred in the final image.

Therefore, according to the present invention, the sheet layer is formed of a member that is triboelectrically charged to the same polarity as the toner, so that the toner is prevented from adhering to the sheet layer and the image defect is prevented. An object of the present invention is to provide a cleaning member for an apparatus and a process cartridge including the cleaning member.

[0022]

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and removes charged toner adhering to the surface of a charging member by rubbing it against the surface of the charging member. In a cleaning member of a charging device, comprising: a sheet layer for supporting the sheet layer, and a base member that elastically presses the sheet layer against the surface of the charging member, the charging member and the sheet layer rub against each other. The sheet layer is formed by a member such that the triboelectrification polarity of the sheet layer at that time is the same as that of the charged toner.

In this case, the sheet layer abuts against the charging member, or the area thereof is set to be equal to or larger than the area of the portion of the base to which the sheet layer is attached, or It is preferable that the charging member is extended to the upstream side in the moving direction and the extension is fixed to a support member to which the base is fixed.

The process cartridge includes a photoconductor,
At least one of a developing device and a cleaning device, the charging member, and any one of the cleaning members described above are integrally housed in a cartridge body, and
It is characterized in that it is detachably attached to the main body of the image forming apparatus.

[0025]

According to the above construction, the sheet layer which rubs against the surface of the charging member is triboelectrically charged to the same polarity as the charged toner by this rubbing, so that the toner is prevented from adhering to the sheet layer due to the electric repulsive force. . As a result, the toner on the charging member is made uniform in thickness by the sheet layer, and when the toner exceeds a certain thickness, the toner is gradually returned to the photosensitive drum.

[0026]

Embodiments of the present invention will be described below with reference to the drawings. <Embodiment 1> FIG. 1 is a longitudinal sectional view of a part of a photosensitive drum 1 as a photoconductor, a charging roller 2 as a charging member, and a cleaning member 3 of a charging device according to the first invention. Is.

The photosensitive drum 1 is a cylindrical substrate 1a made of a conductive material such as aluminum or stainless steel.
And a photosensitive layer 1b that covers the surface of the base body 1a, and is rotationally driven in the direction of arrow R1 by a driving unit (not shown).

The charging roller 2 for charging the photosensitive drum 1 is
It is composed of a metal cored bar 2a arranged at the center, a charging part 2b made of urethane or the like for covering the periphery thereof, and a surface layer 2c made of nylon or the like for coating the surface of the charging part 2b.
The charging roller 2 is rotatably supported and is in contact with the surface of the photosensitive drum 1 with a predetermined pressing force by a biasing member (not shown). Therefore, the charging roller 2 is driven to rotate in the arrow R2 direction as the photosensitive drum 1 rotates in the arrow R1 direction. Further, as described in the related art, the charging roller 2 is applied with a predetermined bias by an external power source, and thereby charges the surface of the photosensitive drum 1 to a predetermined voltage.

The cleaning member 3 is arranged in sliding contact with the charging roller 2. The cleaning member 3 is
The base 3a and the sheet layer 3b are provided. Base 3a
Is formed of a sponge member such as urethane foam (trade name: Moltoprene: Inoac Co., Ltd.) and has an appropriate elasticity. Other than the above, for example, foaming rubber, TPE (thermoplastic elastomer), rubber, or the like can be used as the member forming the base body 3a. The base body 3a is fixed to a cleaner sheet metal 5b as a supporting member by a double-sided tape 3c. The sheet layer 3b is also fixed to the surface of the base body 3a (the lower portion in the figure) by the double-sided tape 3d. The sheet layer 3b is formed of, for example, polyethylene terephthalate (PET) or the like in a sheet shape, and has flexibility and toner is hard to adhere thereto. Other suitable materials for forming the sheet layer 3b include polyesters, polyolefins, cellulose derivatives, vinyl resins,
Examples include plastic sheets such as polycarbonate, polyimide, and polyamide-imide. Cleaning member 3
Are in contact with the charging roller 2 with an appropriate pressing force. That is, the sheet layer 3b on the surface of the cleaning member 3 causes the charging roller 2 to move due to the elastic force of the base body 3a.
The sheet layer 3b is pressed against the surface with an appropriate force, and thus the sheet layer 3b is rubbed by the surface of the charging roller 2 as the charging roller 2 is driven to rotate in the direction of arrow R2. As a result of this rubbing, the sheet layer 3b moves to the photosensitive drum 1
It is triboelectrically charged to the same polarity as the toner T1 on the surface. In this embodiment, the toner that develops the electrostatic latent image formed on the surface of the photosensitive drum 1 is charged with a negative polarity (-), and the sheet layer 3b has the same negative polarity. Sex (-). That is, when the surface layer 2c of the charging roller 2 and the sheet layer 3b of the cleaning member 3 are rubbed,
The material of the sheet layer 3b is selected so that the triboelectric charge polarity of the sheet layer 3b becomes negative.

Next, the operation of the cleaning member 3 will be described. In the present embodiment, a case will be described in which regular development is performed using toner having a negative polarity. Therefore, a (+) charging voltage is applied to the charging roller 2 in order to positively charge the surface of the photosensitive drum 1 (+).

In order to remove the unnecessary toner T1 adhering to the surface of the photosensitive drum 1, a cleaning blade as described in the prior art is brought into contact with the surface of the photosensitive drum 1. After passing through this cleaning blade, the toner T
1 reaches the charging roller 2, the negative toner T1
Adhere to the surface of the positive charging roller 2. When the toner T1 thus attached reaches the cleaning member 3, the sheet layer 3b of the cleaning member 3 comes into close contact with the surface of the charging roller 2 as shown in FIG. The toner T that has entered can be effectively removed. Note that FIG. 7B shows the sheet layer 3
In the conventional example without b, since the base body 3a is formed of a sponge member, it deforms following the toner T on the surface of the charging roller 2 and effectively removes the toner T that has entered the concave portion. I can't. By providing the sheet layer 3b, it is possible to prevent the scratches that have been apt to occur on the surface of the charging roller 2 in the past.

Further, even when the toner T cannot be removed by the sheet layer 3b, the polarity of the sheet layer 3b has the same negative polarity as the toner T1 as shown in FIG.
The toner T1 does not adhere to the sheet layer 3b.
As shown by, a toner layer having a uniform thickness is formed on the surface of the charging roller 2. As a result, the streak-shaped toner adhesion that has conventionally occurred on the surface of the charging roller 2 did not occur, and the vertical streak-shaped charging failure did not occur.

When the toner layer T2 has a certain thickness or more, the toner T4 returns to the photosensitive drum 1 little by little and flows downstream. Therefore, the toner T4 does not form a large lump, so that the toner T4 does not adhere to the surface of the photosensitive drum 1 and block the laser beam during exposure. As a result, no abnormal image is generated. <Sample 1> A cleaning member 3 for a charging member as shown in FIG. 1 was prepared. The materials used at that time are as follows.

Sheet layer (3b): polyethylene terephthalate film (manufactured by Toray, trade name: Lumirror, thickness: 3
6 μm) Substrate (3a): Foaming urethane (manufactured by INOAC, trade name: Moltoprene SM-55) This cleaning device is set in an electrophotographic process cartridge (described later) as shown in FIG.
Repeated 60 images in an environment of ℃ and humidity of 10%
Then, the occurrence of an abnormal image and the surface state of the charging roller 2 after image formation were evaluated. The results are summarized in Table 1.

As the charging member, a two-layer charging roller 2 having a conductive styrene-butadiene rubber base layer and an N-methoxymethylated nylon layer 3c containing conductive carbon dispersed therein is used. did. <Sample 2> Image formation was evaluated in the same manner as in Sample 1 except that the thickness of the sheet material was changed to 14 μm. The results are summarized in Table 1. <Sample 3> As in Example 1, a polyethylene terephthalate film having a thickness of 188 μm was attached as the sheet layer 3b, a cleaning member having the structure shown in FIG. 1 was prepared, and the same image evaluation as in Sample 1 was performed. . The results are summarized in Table 1. <Sample 4> Base 3 as a cleaning member for the charging member
Using only the foamable urethane (a, manufactured by INOAC, trade name: Moltoprene SM-50) which is a, the image formation and evaluation were performed in the same manner as in Sample 1. The results are summarized in Table 1. <Sample 5> Image formation and evaluation were performed in the same manner as in Sample 1 without using the cleaning member for the charging member. The results are summarized in Table 1.

[0036]

[Table 1] <Second Embodiment> FIG. 2 shows a second embodiment. The same members as those in the first embodiment are designated by the same reference numerals, and the description thereof will be omitted.

In this example, instead of the sheet layer 3b of Example 1, a skin layer 3e is formed on the surface of a urethane foam substrate 3a.
Is provided. Since the skin layer 3e can be formed at the same time as the urethane foam is formed, it is not necessary to attach the skin layer 3e to the base body 3a later with a double-sided tape or the like, and the workability is improved and the cost can be significantly reduced. Become. <Embodiment 3> In Embodiment 3, as shown in FIG. 8, the sheet layer 3b of the cleaning member 3 abuts against the surface of the charging roller 2. This is not a hit,
It is not preferable that the entire surface of the sheet layer 3b is in contact with the base sheet 3a, or the base layer 3a is in direct contact with the surface of the charging roller 2 because the width of the sheet layer 3b is narrow. This is because the pressure-sensitive adhesive or the adhesive that adheres the sheet layer 3b to the substrate 3a may contaminate the surface of the charging roller 2. For example, as shown in FIG. 9, when the charging roller 2 is stationary, the sheet layer 3
When the entire surface b is in close contact with the charging roller 2, when the charging roller 2 is driven, the end surface of the sheet layer 3b indicated by M1 in the figure is pulled toward the charging roller 2 side,
The adhesive surface comes into contact with the surface of the charging roller 2. Further, if the charging roller 2 and the sheet layer 3b are left for a long period of time while maintaining contact with each other, the adhesive or pressure sensitive adhesive may seep out from the end portion and contaminate the surface of the charging roller 2.

Further, when the base body 3a is made of a foam material or the like, if the foam material directly rubs the surface of the charging roller 2, the surface of the charging roller 2 is easily damaged by the toner or the like sandwiched between the two. Therefore, in the present embodiment, when the charging roller 2 is stationary, as shown in FIG. 8, the length of the sheet layer 3b supported by the base 3a in the rotating direction of the charging roller 2 is equal to the length of the charging roller 2. The length of the contact portion between the roller 2 and the sheet layer 3b should not be longer than that of the sheet layer 3
Both ends of b are separated from the surface of the roller 2, so that a so-called abdominal contact state is obtained.

In this embodiment, as shown in FIG. 10, the entire substrate 3a may be covered with the sheet layer 3b. However, in this case, as shown in FIG. 11, the cost is higher than that of manufacturing the cleaning member 3 by adhering the sheet layer 3b to only one surface of the base body 3a and cutting the sheet layer 3b. Therefore, the structure of FIG. 8 in which the sheet layer 3b is attached only to the surface of the base body 3a that abuts on the charging roller 2 and is abutted against the charging roller 2 is relatively low in cost, and the desired effect can be obtained. it can.

In the present embodiment, as shown in the figure, the base body 3a may be in the shape of a brush as long as it has flexibility. <Fourth Embodiment> A fourth embodiment will be described with reference to FIG.

In this embodiment, as shown in FIG. 13, the cleaning member 3 is adhered and fixed so as to be bent in a U shape along the protrusion 5c protruding from the cleaner sheet metal 5b.

In the third embodiment, when the hardness of the substrate 3a is lowered, it is necessary to widen the cleaning member 3 in order to surely bring the sheet layer 3b against the surface of the charging roller 2.

However, as shown in this embodiment, the cleaning member 3 is attached along the protrusion 5c, and the sheet layer 3b is formed.
If the sheet layer 3b is fixed in a protruding state, the sheet layer 3b can surely abut against the charging roller 2 and the contact area can be reduced. Therefore, the contact frictional force when the charging roller 2 rotates is reduced, and the driving torque of the charging roller 2 can be suppressed. <Fifth Embodiment> A fifth embodiment will be described with reference to FIG.

In this embodiment, the protrusion 5c used for fixing the cleaning member 3 in the above-mentioned Embodiment 4 is used.
Instead of this, an elastic body 5d having elasticity is used. This makes it possible to bring the sheet layer 3b into contact with the charging roller 2 at a lower pressure than in the fourth embodiment in which the adhesive surface of the base material 3a is fixed. <Example 6> In Example 6, as shown in FIG. 15, in the cleaning member 3 formed by adhesively fixing the sheet layer 3b to the substrate 3a with the double-sided tape 3d, the adhesive of the double-sided tape 3d leaked, and This is an embodiment in which the surface of the charging roller 2 is prevented from being contaminated to cause charging failure. FIG. 21 shows a conventional cleaning member 3. The end portion of the double-sided tape 3d protrudes from the sheet layer 3b.

In this embodiment, the double-sided tape 3d having the same width as the sheet layer 3b and the same width is used. This prevents the double-sided tape 3d from protruding and contaminating the charging roller 2. In addition, as shown in FIG. 16, if a method in which a large double-sided tape is attached in advance to an uncut large sheet layer 3b and then the sheet is cut to a required size, the width and the double-sided surface of the sheet layer 3b as described above are used. The width of the tape 3d can easily be made the same width, and at this time, the cleaning device 3 in which the double-faced tape 3d does not protrude from the sheet layer 3b can be easily manufactured. <Embodiment 7> FIG.
This is the case where the width of d is made narrower than the width of the sheet layer 3b.

As a result, the double-sided tape 3d has a sheet width 3b.
It is easier to stick the sticker so that it does not stick out, and the positioning of the sheet layer 3b is simple. <Embodiment 8> In FIG. 18, a double-sided tape 3d narrower than the width of the sheet layer 3b is provided on the upstream side of the contact position between the sheet layer 3b and the charging roller 2 in the rotation direction (arrow R2 direction) of the charging roller 2. The tape 3d is attached so as not to stick out. As a result, in addition to preventing the charging roller 2 from being contaminated,
It is possible to obtain the cleaning member 3 that is strong against peeling of the sheet layer 3d. Further, as shown in FIG. 19, by using a method in which a double-sided tape having a width equal to or smaller than the width is attached to the center of a sheet layer having a width twice the normal size and cutting is performed at the center, the cleaning member 3 described above can be easily formed. Can be manufactured. <Embodiment 9> FIG. 20 shows the sheet layer 3b on the upstream side of the rotation direction (arrow R2 direction) of the charging roller 2 in the base 3a.
Is attached directly to the same cleaner sheet metal 5b that is fixed by the double-sided tape 3d and backed up by the base material 3a from the back side of the sheet layer 3b at the contact position with the charging roller 2. Thereby, the sheet layer 3b
The adhesion position of is greatly separated from the charging roller 2, and the surface contamination of the charging roller 2 by the double-sided tape 3d is eliminated, and at the same time, the sheet is strong against peeling.

Further, since the base material 3a only plays a role of backing up the sheet layer 3b, the positioning of the cleaning member 3 is relatively easy. <Embodiment 10> In Embodiment 10 shown in FIG. 3, the cleaning member 3 according to any one of Embodiments 1 to 9 is applied to the process cartridge 12. In the figure, 1 is a photosensitive drum, 2 is a charging roller, 3 is a cleaning member of the present invention, 9 is an exposing means such as a laser beam, and 10a.
Is a developing sleeve of the developing device 10, 12a is a cartridge body, and the photosensitive drum 1 and the developing sleeve 10 are rotating in the directions of arrows R1 and R3, respectively. Reference numeral 5 is a cleaning blade for cleaning the transfer residual toner on the photosensitive drum 1, and 16 is a drum shutter for protecting the photosensitive drum. Reference numeral 13 denotes a developing blade for coating the toner on the developing sleeve 10 to a uniform thickness. T is a toner that is a developer. Reference numeral 15 denotes a cleaner toner reservoir for accumulating the toner collected by the cleaning blade 5.

Now, on the charged photosensitive drum 1, printing information is written by the modulated laser beam to form an electrostatic latent image. Then, this electrostatic latent image becomes a visible image (toner image) by the toner T being attached and developed by the developing sleeve 10. The toner image is transferred onto a transfer material by a transfer device (not shown) and then fixed by a fixing device.

Further, the cleaning member 3 housed in the process cartridge 12 has the triboelectrification polarity equal to that of the toner T and the sheet layer and opposite to that of the charging roller 2 as described in the first and second embodiments. Since the material is selected, no electrification failure or abnormal image is generated. Further, even if the substrate is made of a flexible sponge member, the sheet layer adheres to the surface of the charging roller 2 by sticking the sheet layer thereon even when the surface of the charging roller 2 has irregularities. Accordingly, it is possible to prevent the sheet layer from sticking to the concave portion on the surface of the charging roller 2 where the stain is accumulated when the sheet layer is not present and the stain is accumulated.

Further, since the sheet layer having extremely less unevenness on the surface than the sponge member is brought into contact with the charging roller 2, streak-like toner sticking does not occur.

As described above, the streak-shaped toner sticking that has occurred in the conventional example does not occur, and the vertical streak-shaped charging failure does not occur. Further, when the toner layer on the surface of the charging roller 2 has a certain thickness or more, the toner is returned to the photosensitive drum 1 little by little and is flowed downstream. Therefore, since the toner does not form a large lump, the toner does not adhere to the surface of the photosensitive drum 1 and block the exposure. As a result, it has become possible to supply a very compact process cartridge without abnormal images.

Needless to say, the first invention can be applied not only to the charging roller 2 but also to a charging member such as a transfer roller. Further, the polarity of the toner is not limited to minus and may be plus. In this case, the member for forming the sheet layer may be selected such that the triboelectric charge polarity becomes positive when the charging roller 2 is rubbed.

[0053]

As described above, according to the present invention,
By forming the sheet layer of the cleaning member by a member whose frictional charging polarity with the charging member is the same as that of the charged toner, it becomes difficult for toner to adhere to the sheet layer due to electric repulsive force. As shown in the figure, toner accumulates between the sheet layer and the charging member to form a lump, and then this lump drops and adheres to the photosensitive drum to block exposure during latent image formation, resulting in an image defect due to a latent image defect. It is possible to effectively prevent such a trouble as to occur.

[Brief description of drawings]

FIG. 1 is a vertical cross-sectional view showing the configuration and operation of a cleaning member according to a first embodiment.

FIG. 2 is a vertical cross-sectional view showing the configuration and operation of a cleaning member according to a second embodiment.

FIG. 3 is a cross-sectional view showing the structure of a process cartridge of Example 10.

FIG. 4 is a vertical sectional view showing a conventional cleaning member, a charging roller, and the like.

FIG. 5 is an explanatory view showing defects that similarly appear on the surface of the charging roller and the surface of the transfer material.

FIG. 6 is a cross-sectional view showing the structure and operation of the cleaning member.

FIG. 7A is a vertical cross-sectional view showing the operation of the cleaning member according to the first embodiment. FIG. 6B is a vertical sectional view showing the operation of the conventional cleaning member.

FIG. 8 is a vertical cross-sectional view showing the configuration and operation of the cleaning member according to the third embodiment.

FIG. 9 is a vertical cross-sectional view showing the configuration and operation of a conventional cleaning member.

FIG. 10 is a vertical cross-sectional view showing the configuration and operation of another cleaning member according to the third embodiment.

11 is a perspective view showing a method of manufacturing the cleaning member shown in FIG.

FIG. 12 is a vertical cross-sectional view showing the configuration and operation of another cleaning member according to the third embodiment.

FIG. 13 is a vertical cross-sectional view showing the configuration and operation of the cleaning member according to the fourth embodiment.

FIG. 14 is a vertical cross-sectional view showing the configuration and operation of the cleaning member according to the fifth embodiment.

FIG. 15 is a vertical sectional view showing the configuration and operation of the cleaning member according to the sixth embodiment.

16 is a perspective view showing a method of manufacturing the cleaning member shown in FIG.

FIG. 17 is a vertical cross-sectional view showing the configuration and operation of the cleaning member according to the seventh embodiment.

FIG. 18 is a vertical cross-sectional view showing the configuration and operation of the cleaning member according to the eighth embodiment.

FIG. 19 is a perspective view showing a method of manufacturing the cleaning member shown in FIG.

FIG. 20 is a vertical cross-sectional view showing the configuration and operation of the cleaning member according to the ninth embodiment.

FIG. 21 is a vertical cross-sectional view showing the configuration and operation of a conventional cleaning member.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Photoconductor (photosensitive drum) 2 Charging member (charging roller) 3 Cleaning member 3a Base (sponge member) 3b Sheet layer 5 Cleaning device (cleaning blade) 5b Supporting member (cleaner sheet metal) 10 Developing device 12 Process cartridge 12a Cartridge body T Charged toner (toner)

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Erika Asano 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc. (72) Inventor Hiroaki Ogata 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Within the corporation

Claims (5)

[Claims] 1. A sheet layer for removing charged toner adhering to the surface of a charging member by rubbing the surface of the charging member, and a sheet layer supporting the sheet layer and attaching the sheet layer to the charging member. In a cleaning member of a charging device including a base body that elastically presses the surface, a frictional charging polarity of the sheet layer when the charging member and the sheet layer rub against each other has the same polarity as that of the charged toner. A cleaning member for a charging device, characterized in that the sheet layer is formed by another member. 2. The cleaning member according to claim 1, wherein the sheet layer abuts against the charging member. 3. The cleaning member according to claim 1, wherein an area of the sheet layer is set to be equal to or larger than an area of a portion of the base to which the sheet layer is attached. 4. The sheet layer is extended to the upstream side in the moving direction of the charging member, and the extended portion is fixed to a support member to which the base body is fixed. Cleaning member. 5. The cartridge main body integrally houses at least one of a photoconductor, a developing device, and a cleaning device, the charging member, and the cleaning member according to any one of claims 1 to 4. The process cartridge is detachably attached to the main body of the image forming apparatus.