JP2011137857A - Cleaning device and image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a cleaning device and an image forming apparatus configured to adjust, even when an amount of toner supplied to a cleaning roller changes, the thickness of a toner layer formed on the surface of the cleaning roller, stably polish a photoreceptor drum by firmly adhering toner to the cleaning roller, and stably polish the photosensitive drum for a long time without wearing a member constituting the cleaning device. <P>SOLUTION: The cleaning device includes: a cleaning roller disposed in contact with a photoreceptor drum; and a toner layer thickness regulating member for regulating the thickness of toner adhered onto the surface of the cleaning roller. The toner layer thickness regulating member is a toner layer thickness regulating roller rotated in contact with the cleaning roller. The cleaning device is provided with a toner pressing member disposed downstream of the toner layer thickness regulating roller in the rotating direction of the cleaning roller so as to be in contact with the cleaning roller. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a cleaning device used in an image forming apparatus such as a copying machine or a printer, and an image forming apparatus including the cleaning device.

In an image forming apparatus such as a copying machine or a printer, an image forming unit is provided with a photosensitive drum. After an electrostatic latent image is formed on the surface of the photosensitive drum, toner adheres to the toner image. It is formed.
The toner image is transferred to a transfer medium such as paper, but the toner is not completely transferred and remains on the surface of the photosensitive drum, or discharge products generated when forming an electrostatic latent image are generated on the photosensitive drum. It remains attached to the drum surface. Such residual toner and discharge products hinder the formation of a new image and cause a failure to obtain a good transfer image. For this reason, the image forming apparatus is provided with a cleaning device for removing deposits (toner, discharge products, etc.) on the surface of the photosensitive drum.

FIG. 4 is a schematic sectional view of a conventional cleaning device.
The cleaning device (a) includes a cleaning blade (c) that scrapes off the deposits on the surface of the photosensitive drum (b), a cleaning roller (d) that rotates in contact with the photosensitive drum (b), and the cleaning device (a). A recovery screw (e) for recovering deposits is provided.
The cleaning roller (d) in contact with the photosensitive drum (b) holds the toner and forms a toner layer on the surface of the cleaning roller (d) in addition to the function of removing the toner. It also has a function of polishing.
However, in the conventional cleaning device (a), since the amount of toner held on the cleaning roller (d) is not constant, it is difficult to make the thickness of the toner layer formed on the surface of the cleaning roller (d) uniform. Met. Therefore, the cleaning device (a) having the above configuration cannot stably polish the photosensitive drum.

In order to solve the above problems, Patent Document 1 discloses a cleaning device that stores toner removed from a photosensitive drum by a cleaning blade in a toner receiving member provided below a cleaning roller.
In the disclosed technique of Patent Document 1, the toner remaining on the surface of the photosensitive drum is scraped off by a cleaning blade, the scraped toner is stored in a toner receiving member provided below the cleaning roller, and the stored toner is stored in the cleaning roller. The surface of the photosensitive drum is held and polished.
By providing the toner receiving member below the cleaning roller, it is possible to supply and hold a sufficient amount of toner to the cleaning roller, thereby enhancing the polishing effect.

However, if the amount of toner adhering to the surface of the photosensitive drum is excessive, the amount of toner stored in the toner receiving member will be excessive, and the amount of toner held by the cleaning roller may increase and reattach to the photosensitive drum. was there. Further, if the amount of toner is too small, sufficient polishing is not performed, so that it is necessary to supply toner.
Therefore, in the technique described in Patent Document 1, since the polishing effect changes depending on the increase or decrease in the toner amount, stable polishing is difficult.

On the other hand, Patent Document 2 discloses a cleaning device including a toner receiving member provided below a cleaning roller and a scraper for scraping off the toner held by the cleaning roller.
The technology disclosed in Japanese Patent Laid-Open No. 2004-228561 is a technique in which a toner stored in a toner receiving member is held by a cleaning roller, and a scraper is used to scrape the toner in order to adjust the toner amount.
When the disclosed technique of Patent Document 2 is used, a sufficient amount of toner can be supplied to the cleaning roller and the amount of toner can be adjusted by scraping off the toner. Therefore, the polishing effect is not easily changed.

However, in the disclosed technique of Patent Document 2, there is a possibility that the toner held on the cleaning roller is excessively removed, and the toner is fused to each member due to friction between the cleaning roller and the scraper. .
Furthermore, when used over a long period of time, there is a problem that the scraper is partially worn and uniform polishing cannot be performed. That is, when the scraper is partially worn, the amount of toner on the cleaning roller cannot be adjusted, and the toner layer thickness of the cleaning roller is increased. Therefore, the surface of the photosensitive drum is excessively polished.
In addition, the toner layer that comes into contact with other parts than the worn part of the scraper is thinner than the part corresponding to the worn part, so that the pressing force of the cleaning roller to the photosensitive drum is small and polishing cannot be performed sufficiently. there were. Therefore, even if the technique disclosed in Patent Document 2 is used, it is difficult to polish the photosensitive drum stably over a long period of time.

In addition to the problems described above, the conventional cleaning device has a toner layer uniformly formed on the surface of the cleaning roller, but if the toner does not adhere strongly to the surface of the cleaning roller, There is a problem that the toner is scattered or detached before reaching the surface, and a sufficient polishing effect cannot be obtained.
Such a problem cannot be solved by the disclosed techniques of Patent Documents 1 and 2.

JP 2007-108269 A JP 2009-104007 A

  The present invention has been made to solve the above-described problems of the prior art, and adjusts the thickness of the toner layer formed on the surface of the cleaning roller even if the amount of toner supplied to the cleaning roller changes. In addition, the photosensitive drum can be stably polished by strongly adhering the toner to the cleaning roller, and the photosensitive drum can be stably polished over a long period of time without wearing the members constituting the cleaning device. A cleaning device and an image forming apparatus are provided.

  The invention according to claim 1 is a cleaning device comprising: a cleaning roller disposed in contact with the photosensitive drum; and a toner layer thickness regulating member that regulates the thickness of the toner layer attached to the surface of the cleaning roller, The toner layer thickness regulating member is a toner layer thickness regulating roller that rotates in contact with the cleaning roller, and is in contact with the cleaning roller and disposed downstream of the toner layer thickness regulating roller in the rotation direction of the roller. The present invention relates to a cleaning device including a toner pressing member.

  The invention according to claim 2 relates to the cleaning device according to claim 1, wherein the toner pressing member is a cylindrical member that rotates in contact with the cleaning roller.

  The invention according to claim 3 relates to the cleaning device according to claim 2, wherein the rotation direction of the columnar member and the cleaning roller is the same in the contact portion.

  The invention according to claim 4 relates to the cleaning device according to claim 2 or 3, wherein the cylindrical member has an outer diameter of 6 to 10 mm.

  The invention according to claim 5 relates to the cleaning device according to any one of claims 2 to 4, wherein the columnar member is made of metal.

  The invention according to claim 6 relates to the cleaning device according to claim 1, wherein the toner pressing member is a plate-like elastic member that comes into contact with the cleaning roller by a spring property.

  The invention according to claim 7 relates to the cleaning device according to claim 6, wherein the plate-like elastic member is made of metal or resin.

  The invention according to claim 8 relates to an image forming apparatus comprising the cleaning device according to any one of claims 1 to 7.

  The invention according to claim 9 relates to the image forming apparatus according to claim 8, wherein the outermost layer of the photosensitive drum is amorphous silicon.

  A tenth aspect of the present invention relates to the image forming apparatus according to the eighth or ninth aspect, wherein the cleaning device is installed vertically above the photosensitive drum.

According to the first aspect of the present invention, there is provided a cleaning device comprising: a cleaning roller disposed in contact with the photosensitive drum; and a toner layer thickness regulating member that regulates the thickness of the toner layer attached to the surface of the cleaning roller. The toner layer thickness regulating member is a toner layer thickness regulating roller that rotates in contact with the cleaning roller, and is in contact with the cleaning roller and disposed downstream of the toner layer thickness regulating roller in the rotation direction of the roller. By providing the toner pressing member, the amount of toner held on the surface of the cleaning roller can be adjusted even if the amount of toner supplied to the cleaning roller changes, and the thickness of the formed toner layer is uniform. Toner layer that does not cause toner scattering or detachment due to strong adhesion of toner It can be formed.
Accordingly, the surface of the photosensitive drum can be uniformly and sufficiently polished. Further, the wear of each member such as the cleaning roller and the toner layer thickness regulating roller can be reduced, and the photosensitive drum can be stably polished even for a long period of use.

  According to the second aspect of the present invention, the toner pressing member is a cylindrical member that rotates in contact with the cleaning roller, so that the toner can be strongly adhered over the entire cleaning roller.

  According to the third aspect of the present invention, the rotation direction of the cylindrical member and the cleaning roller is the same in the contact portion, so that the cleaning roller is worn compared to the case where the rotation direction is the reverse direction. Can be prevented.

  According to the fourth aspect of the present invention, since the cylindrical member has an outer diameter of 6 to 10 mm, there is no possibility that the cylindrical member is bent, and the toner layer of the cleaning roller can be pressed uniformly. Since the contact area is small, the toner layer can be pressed efficiently.

  According to the fifth aspect of the present invention, since the cylindrical member is made of metal, the pressing force to the cleaning roller is increased, and the toner can be adhered more strongly. Moreover, since it is excellent in durability, the toner layer of the cleaning roller can be stably pressed even during long-term use.

  According to the sixth aspect of the invention, since the toner pressing member is a plate-like elastic member that contacts the cleaning roller due to the spring property, the spring force is used to press, so that the adhesion force of the toner layer is improved. Can be made. In addition, it is possible to press the toner layer with a simple configuration and to save space.

  According to the seventh aspect of the invention, since the plate-like elastic member is made of metal or resin, it becomes a highly rigid toner pressing member, so that the toner layer can be effectively pressed.

  According to an eighth aspect of the present invention, by providing the cleaning device according to any one of the first to seventh aspects, the surface of the photosensitive drum can be stably and evenly provided that the cleaning roller is not worn even during long-term use. Thus, an image forming apparatus can be provided in which no image defects occur.

  According to the ninth aspect of the present invention, by providing the cleaning roller with a uniform thickness and a strong toner layer, stable polishing can be performed without damaging the amorphous silicon layer, and image defects may occur. There is no.

  According to the tenth aspect of the present invention, since the cleaning device is installed vertically above the photosensitive drum, it is possible to prevent toner from dropping and prevent toner from accumulating in the cleaning device. .

FIG. 3 is a schematic cross-sectional view of the cleaning device according to the present invention, in which (a) is a schematic diagram using a cylindrical member as a toner pressing member, and (b) is a schematic diagram using a plate-like elastic member as a toner pressing member. It is. FIG. 3 is a schematic cross-sectional view when the cleaning device according to the present invention is installed on the side of the photosensitive drum. 1 is a schematic cross-sectional view showing an image forming apparatus according to the present invention. It is a schematic sectional drawing of the conventional cleaning apparatus.

Hereinafter, a cleaning device and an image forming apparatus according to the present invention will be described with reference to the drawings.
FIG. 1 is a schematic sectional view of a cleaning device according to the present invention.
The cleaning device (1) is provided so as to face the photosensitive drum (2). The cleaning roller (3) rotates in contact with the photosensitive drum (2), and rotates in contact with the cleaning roller (3). The toner layer thickness regulating roller (4), the toner pressing member (5) disposed in contact with the cleaning roller (3) separately from the toner layer thickness regulating roller (4), and the surface of the photosensitive drum (2). A cleaning blade (6) for scraping off deposits (toner, discharge products, etc.) and a recovery screw (7) for recovering deposits removed from the photosensitive drum (2) are provided.

Even if the amount of toner supplied to the cleaning roller (3) changes by rotating the toner layer thickness regulating roller (4) in contact with the cleaning roller (3), the circumferential direction and the axial direction of the cleaning roller (3) In either case, a constant amount of toner can be held and a toner layer having a uniform thickness can be formed. That is, both the cleaning roller (3) and the toner layer thickness regulating roller (4) hold the toner, and the rollers whose surface layers are covered with the toner are rubbed with each other.
Accordingly, wear of the cleaning roller (3) and the toner layer thickness regulating roller (4) is prevented, and wear deterioration of the roller can be prevented even during long-term use.

By providing the toner layer thickness regulating roller (4), a toner layer having a uniform thickness can be formed on the surface of the cleaning roller (3) as described above.
However, when an elastic body such as foamed rubber is used for the cleaning roller (3), the toner does not adhere strongly, and therefore before reaching the nip portion between the cleaning roller (3) and the photosensitive drum (2). There is a risk that the toner may be scattered or detached.
The toner pressing member (5) is provided in contact with the cleaning roller (3), and is disposed downstream of the toner layer thickness regulating roller (4) in the rotation direction of the cleaning roller (3) (see the arrow in FIG. 1). The
With such an arrangement, the toner layer having a uniform thickness can be pressed by the toner layer thickness regulating roller (4), and the toner can be strongly adhered to the cleaning roller (3). By strongly adhering the toner to the cleaning roller (3), the toner can be prevented from being scattered and detached, and the photosensitive drum (2) can be effectively polished.

The shape of the toner pressing member (5) is preferably a columnar shape or a plate shape (see FIG. 1).
FIG. 1A is a schematic sectional view of a cleaning device using a cylindrical member (51) as a toner pressing member (5).
When the cylindrical member (51) is used as the toner pressing member (5), it is brought into contact with the cleaning roller (3) and rotated. By rotating the columnar member (51), the toner can be strongly adhered over the entire cleaning roller (3).

The cylindrical member (51) preferably rotates in the same direction as the cleaning roller (3) at the contact portion with the cleaning roller (3) (see FIG. 1A). By doing so, wear of the cleaning roller (3) can be suppressed compared to the case of reverse rotation.
When rotating the columnar member (51), it may be applied only to the cleaning roller (3), but it may be rotated by biting into the cleaning roller (3). When biting in, the biting depth is preferably 0.2 mm or less. If it exceeds 0.2 mm, the cylindrical member (51) may be bent, and it will be difficult to press the toner layer uniformly.

The size of the columnar member (51) is not particularly limited, but the length in the longitudinal direction is preferably substantially the same as that of the cleaning roller (3). By doing so, the cylindrical member (51) abuts over the entire axial length of the cleaning roller (3), and the surface of the cleaning roller (3) can be efficiently rubbed.
Moreover, it is preferable that the outer diameter of a cylindrical member (51) is 6-10 mm. By doing so, the cylindrical member (51) comes into contact with the cleaning roller (3) without being bent, and the toner layer formed on the cleaning roller (3) can be pressed uniformly, and the contact area is small. Therefore, the toner layer can be pressed efficiently and the toner can be strongly adhered.
When the outer diameter of the columnar member (51) is less than 6 mm, the columnar member (51) bends and cannot sufficiently press the cleaning roller (3). On the other hand, when the outer diameter exceeds 10 mm, the cleaning roller (3 ) And the contact area becomes large, it is not possible to press efficiently, which is not preferable in either case.

The material of the columnar member (51) is not particularly limited, but metal, foamed resin, foamed rubber, etc. are used, and metal is particularly preferably used.
By using a metal, the pressing force becomes higher than when foamed resin, foamed rubber, or the like is used, and the toner can be adhered more strongly and the toner can be prevented from being detached. Moreover, since it is excellent in durability, the toner layer formed on the cleaning roller (3) can be stably pressed without causing wear deterioration even during long-term use.

FIG. 1B is a schematic cross-sectional view of a cleaning device using a plate-like elastic member (52) for the toner pressing member (5).
When the plate-like elastic member (52) is used as the toner pressing member (5), it comes into contact with the cleaning roller (3) due to its spring property and presses the surface of the cleaning roller (3) with its elastic restoring force. That is, the plate-like elastic member (52) acts like a leaf spring and presses the surface of the cleaning roller (3).

The plate-like elastic member (52) is disposed so as to bite into the cleaning roller (3), and the biting depth is desirably 0.2 mm or less. If the thickness exceeds 0.2 mm, the friction increases and the toner layer cannot be pressed sufficiently, which is not preferable.
By using the plate-like elastic member (52), it is possible to effectively press the toner layer with a simple configuration and to save space.

  In the illustrated example, the plate-like elastic member (52) is bent in a letter shape with a bent portion inner angle of 90 ° or less, and one surface sandwiching the bending point is the inner surface of the housing (8) of the cleaning device (1). The other surface is in contact with the surface of the cleaning roller (3).

The material of the plate-like elastic member (52) is not particularly limited, but when a metal or resin is used, the toner layer can be effectively pressed because of its high rigidity.
Examples of the metal include aluminum (Al) and stainless steel (SUS), and examples of the resin include high-density polyethylene (HDPE), polyethylene terephthalate (PET), and polytetrafluoroethylene (PTFE). In particular, the resin is preferably used because it can have good slidability and can prevent an increase in the coefficient of friction.
When using resin, it is good also as a plate-shaped elastic member (52) by laminating | stacking several film-like resin to make plate shape.

The size of the toner pressing member (5) using the plate-like elastic member (52) is not particularly limited, but is preferably a length that can contact the entire length of the cleaning roller (3) in the axial direction. By doing so, the toner pressing member (5) abuts over the entire axial length of the cleaning roller (3), and the surface of the cleaning roller (3) can be efficiently rubbed.
The thickness is set so as to have appropriate springiness and rigidity, for example, 0.1 to 1.0 mm.

An abrasive such as titanium oxide (TiO ₂ ) may be added to the toner.
When the abrasive is added, the toner containing the abrasive is held on the cleaning roller (3) to form a toner layer, adjusted to a uniform thickness by the toner layer thickness regulating roller (4), and further a toner pressing member ( According to 5), the toner containing the abrasive is strongly adhered. The surface of the photosensitive drum (2) is uniformly polished by the cleaning roller (3).

The material of the outermost layer of the photosensitive drum (2) with which the cleaning roller (3) contacts is not particularly limited, and amorphous silicon, an organic photosensitive member (OPC), or the like can be used.
When the cleaning device (1) according to the present invention is used, even the photosensitive drum (2) having the outermost layer made of amorphous silicon can be stably and sufficiently polished, and a defect (image) There is no risk of generating a flow or a dash mark.

The cleaning device (1) according to the present invention is preferably installed above the photosensitive drum (2) in the vertical direction, as shown in FIG. By doing so, toner drop is prevented, and toner can be prevented from accumulating in the cleaning device (1) (A portion in FIG. 1).
However, the installation position of the cleaning device (1) is not limited to the upper side in the vertical direction of the photosensitive drum (2), and can be installed on the side of the photosensitive drum (2) (see FIG. 2). Even when installed on the side of the photosensitive drum (2), the toner layer can be strongly adhered to the cleaning roller (3) by preventing scattering and detachment of the toner, and the photosensitive drum (2) can be effectively applied. ) Can be polished.

FIG. 3 is a schematic sectional view showing the image forming apparatus according to the present invention.
The image forming apparatus in the illustrated example is a printer, but may be a copying machine or a facsimile.
An image forming apparatus according to the present invention includes the above-described cleaning device (1).

  The image forming apparatus of the illustrated example includes a paper feed cassette (12) stored inside the printer main body (11) and paper (not shown) stored in a storage space (13) of the paper feed cassette (12). A paper feed unit (14) for taking out paper, a manual feed tray (15) installed in front of the printer main body (11), and a manual paper feed unit for taking out paper (not shown) set in the manual feed tray (15) ( 16), the transport path (17) through which the paper supplied from each paper feed unit (14), (16) is transported, and the paper transport direction from the junction of each paper feed unit (14), (16) The registration roller pair (18) disposed on the downstream side, the image forming unit (19) disposed on the downstream side in the paper transport direction from the registration roller pair (18), and the paper transport direction from the image forming unit (19) Fix the image (toner image) placed downstream And Chakusochi (20), and a reverse path for pulling back the sheet in the sheet conveyance direction upstream side (21), sheet discharge unit provided at the terminal end of the transport path (17) and (22).

The image forming unit (19) includes a photosensitive drum (2), a cleaning device (1) disposed around the photosensitive drum (2), a charging device (23), a transfer device (24), and a developing device (25). ) And an exposure device (26).
As a result, in the image forming section (19), the photosensitive drum (2) is rotationally driven at a predetermined process speed (circumferential speed) by a driving means (not shown), and its surface is predetermined by the charging device (23). Uniformly charged to polarity and potential.

  An electrostatic latent image is formed on the surface of the charged photosensitive drum (2) by the exposure device (26). The exposure device (26) irradiates the surface of the photosensitive drum (2) with a laser beam (not shown), removes the charge of the laser beam irradiated portion on the surface of the photosensitive drum (2), and responds to image information. An electrostatic latent image is formed.

  The electrostatic latent image formed on the surface of the photosensitive drum (2) is developed as a toner image by electrostatically adhering toner having a charge supplied from the toner container (27) by the developing device (25). The Further, the toner image is transferred onto the paper as a transfer image by the transfer device (24). At this time, the photosensitive drum (2) having the toner image transferred onto the paper is freed of residual toner, discharge products and the like by the cleaning device (1), and is further removed by a static eliminator (not shown) during the next image formation. Static elimination treatment for charging is performed.

  The image forming apparatus according to the present invention is an image forming apparatus in which image defects (image flow, dash marks, etc.) do not occur because the surface of the photosensitive drum (2) is stably polished even after long-term use.

Hereinafter, the effect of the present invention will be clarified by showing examples of the cleaning apparatus according to the present invention.
However, the present invention is not limited to the following examples.

(Example)
The cleaning device according to the present invention was mounted on an image forming apparatus (TASKalfa 500ci), and the thickness of the toner layer formed on the cleaning roller after printing was evaluated.
Urethane foam rubber (outer diameter 15.5 mm, wall thickness 1.75 mm) is used for the cleaning roller, plate-like urethane rubber (thickness 2.2 mm) is used for the cleaning blade, and the outermost layer of the photosensitive drum is made of amorphous silicon. Externally added titanium oxide (TiO ₂ ).
The linear speed of the photosensitive drum was 210 mm / sec, and the linear speed of the cleaning roller was 168 mm / sec.
Also, a sponge roller (foamed urethane, outer diameter 11 mm, wall thickness 1.5 mm) was used as the toner layer thickness regulating roller, and the rotation directions of the cleaning roller and the toner layer thickness regulating roller were the same at the contact portion. The linear velocity of the toner layer thickness regulating roller with respect to the cleaning roller was set to a constant velocity (1.0 times).
Example 1 and Example 2 were obtained by using a cylindrical member and a plate-like elastic member as the toner pressing member, respectively.
A metal (SUS304, outer diameter 8 mm) was used as the columnar member of Example 1, and a resin (PET, thickness 0.1 mm) was used as the plate-like elastic member of Example 2. In addition, the cleaning device in each example has the device configuration shown in FIGS. 1 (a) and 1 (b).
A continuous printing of 10,000 sheets was performed on A4 size paper (transfer paper) at a printing rate of 2%, and the thickness of the toner layer was evaluated. The thickness of the toner layer was measured at five locations in the axial direction of the cleaning roller, and the average and variation were obtained.
To measure the toner layer thickness, a laser outer diameter measuring device was used to measure the outer diameter of the roller with the toner attached and the outer diameter of the roller with the toner removed from the air, and the difference between them was determined. It was.
Further, Comparative Example 1 was obtained by performing the above printing operation without installing a toner pressing member.
The results are shown in Table 1.

  It was found that by bringing the toner pressing member into contact with the cleaning roller, the toner layer thickness in the cleaning roller axial direction can be made substantially uniform, and the thickness of the toner layer can be adjusted. On the other hand, it was found that when the toner pressing member is not installed, the toner layer thickness increases and the toner layer thickness in the cleaning roller axial direction cannot be made uniform.

  The present invention is preferably used for an image forming apparatus including a cleaning device such as a printer, a copying machine, and a facsimile machine.

DESCRIPTION OF SYMBOLS 1 Cleaning apparatus 2 Photosensitive drum 3 Cleaning roller 4 Toner layer thickness control roller 5 Toner pressing member 51 Columnar member 52 Plate-like elastic member

Claims (10)

A cleaning device comprising: a cleaning roller disposed in contact with the photosensitive drum; and a toner layer thickness regulating member that regulates the thickness of the toner layer attached to the surface of the cleaning roller,
A toner layer thickness regulating roller in which the toner layer thickness regulating member rotates in contact with the cleaning roller;
A cleaning device, comprising: a toner pressing member that contacts the cleaning roller and is disposed downstream of the toner layer thickness regulating roller in a rotation direction of the roller.   The cleaning device according to claim 1, wherein the toner pressing member is a cylindrical member that rotates in contact with the cleaning roller.   The cleaning device according to claim 2, wherein the rotation direction of the columnar member and the cleaning roller is the same in the contact portion.   The cleaning apparatus according to claim 2 or 3, wherein an outer diameter of the cylindrical member is 6 to 10 mm.   The cleaning apparatus according to claim 2, wherein the cylindrical member is made of metal.   The cleaning device according to claim 1, wherein the toner pressing member is a plate-like elastic member that comes into contact with the cleaning roller by a spring property.   The cleaning apparatus according to claim 6, wherein the plate-like elastic member is made of metal or resin.   An image forming apparatus comprising the cleaning device according to claim 1.   9. The image forming apparatus according to claim 8, wherein the outermost layer of the photosensitive drum is amorphous silicon.   The image forming apparatus according to claim 8, wherein the cleaning device is installed vertically above the photosensitive drum.

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