JP5266264B2 - Cleaning device and image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a cleaning device and an image forming apparatus stably polishing a photoreceptor drum even if the toner amount supplied to a cleaning roller changes. <P>SOLUTION: The cleaning device 1 includes the cleaning roller 3, a cleaning blade 5 for scratching toner adhering to a drum 2 surface on the downstream side of the cleaning roller 3 in the rotating direction of the photoreceptor drum 2, and a toner layer thickness regulating member 4 for regulating the toner layer thickness adhering to the cleaning roller 3 surface. The toner layer thickness regulating member 4 abuts on the cleaning roller 3 and rotates, and is arranged on the downstream side when viewed from the photoreceptor drum 2 in the rotating direction of the cleaning roller 3. A toner receiving member 6 capable of supplying toner removed from the photoreceptor drum 2 by the cleaning blade 5 to the cleaning roller 3 is installed under the cleaning roller 3. <P>COPYRIGHT: (C)2011,JPO&amp;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. 5 is a schematic cross-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.

  Also, when the printing rate is low or when monochrome printing with a color copying machine, if the toner on the surface of the photosensitive drum (b) is scraped off by the cleaning blade (c), the toner becomes insufficient, and the cleaning roller (d) is sufficient. There is a problem that it is difficult to form a toner layer having a sufficient thickness.

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.

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. The present invention provides a cleaning device and an image forming apparatus that can stably polish the photosensitive drum and can stably polish the photosensitive drum over a long period of time without wearing the members constituting the cleaning device. To do.

The invention according to claim 1 is provided with a cleaning roller disposed in contact with the photosensitive drum, and in contact with the photosensitive drum downstream of the cleaning roller in the rotational direction of the photosensitive drum, A cleaning device comprising a cleaning blade that scrapes off toner adhering to the drum surface, and a toner layer thickness regulating member that regulates the thickness of the toner layer adhering to the cleaning roller surface, wherein the toner layer thickness regulating member is the cleaning roller A toner layer thickness regulating roller that rotates in contact with the cleaning roller , and is disposed slightly downstream of the cleaning roller and downstream of the cleaning drum in the rotation direction of the cleaning roller. The toner removed from the photosensitive drum by a blade is removed by the cleaning. Is installed toner receiving member which can be supplied to the over La beneath the cleaning roller, the contact portion of long and the cleaning roller and the toner layer thickness regulating roller than from the cleaning blade near the center position of the cleaning roller The present invention relates to a cleaning device that extends to a distance shorter than the position .

According to a second aspect of the present invention, in the cleaning device according to the first aspect, the rotation directions of the photosensitive drum, the cleaning roller, and the toner layer thickness regulating roller are the same in the respective contact portions. About.

A third aspect of the present invention relates to the cleaning apparatus according to the first or second aspect, wherein the photosensitive drum is made of amorphous silicon.

A fourth aspect of the present invention relates to an image forming apparatus comprising the cleaning device according to any one of the first to third aspects.

According to the first aspect of the present invention, the cleaning roller disposed in contact with the photosensitive drum and the downstream side of the cleaning roller in the rotational direction of the photosensitive drum are provided in contact with the photosensitive drum. A cleaning blade that scrapes off the toner adhering to the drum surface, and a toner layer thickness regulating member that regulates the thickness of the toner layer adhering to the cleaning roller surface, wherein the toner layer thickness regulating member is the A toner layer thickness regulating roller that rotates in contact with the cleaning roller, and is disposed downstream of the photosensitive drum in the rotational direction of the cleaning roller, and is removed from the photosensitive drum by the cleaning blade; Toner receiving member capable of supplying the cleaned toner to the cleaning roller Wherein by being placed under the cleaning roller, it is possible to maintain the thickness of the toner layer on the cleaning roller may supply volume is changed in the toner from the photosensitive drum uniformly. That is, since the toner stored in the toner receiving member is supplied to the cleaning roller, a toner layer having a sufficient thickness for polishing the photosensitive drum can be formed even if the toner amount is reduced.
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 first aspect of the present invention, the toner receiving member is longer from the vicinity of the cleaning blade than the central position of the cleaning roller and shorter than the contact position of the cleaning roller and the toner layer thickness regulating roller. By extending to the distance, toner is supplied only from the toner receiving member to the cleaning roller, and a toner layer having a sufficient and uniform thickness can be formed on the cleaning roller.

According to the first aspect of the present invention, since the toner layer thickness regulating roller is provided slightly below the cleaning roller, it is possible to reduce the size of the cleaning device and save space.

According to the second aspect of the present invention, when the rotation direction of the photosensitive drum, the cleaning roller, and the toner layer thickness regulating roller is the same in each contact portion, the rotation direction is reverse. In comparison, wear of each member can be prevented.

According to the third aspect of the present invention, the cleaning roller having a uniform toner layer thickness does not damage the photosensitive layer of the amorphous silicon photoconductor that is liable to cause surface defects such as image flow due to adhesion of charged products. Thus, a cleaning device capable of positive and stable polishing can be provided.

According to the fourth aspect of the present invention, the cleaning device according to any one of the first to third aspects is provided, so that the cleaning roller is not worn even during long-term use, and the photoreceptor is stably and uniformly. An image forming apparatus in which the drum surface is polished and image defects do not occur can be obtained.

It is a schematic sectional drawing of the cleaning apparatus which concerns on this invention. It is a schematic sectional drawing which shows other embodiment of the cleaning apparatus which concerns on this invention. It is a schematic sectional drawing which shows another embodiment of the cleaning apparatus which concerns on this invention. 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). And a cleaning blade (5) for scraping off deposits (toner, discharge products, etc.) on the surface of the photosensitive drum (2). Further, below the cleaning roller (3), a toner receiving member (6) for storing the toner removed from the photosensitive drum (2), and a toner that becomes excessive and cannot be stored in the toner receiving member (6) are collected. A recovery screw (7) is provided.

The toner layer thickness regulating roller (4) is installed on the downstream side of the cleaning roller (3) as viewed from the photosensitive drum (2) (on the opposite side of the photosensitive drum (2) across the cleaning roller (3)). And rotates in contact with the cleaning roller (3).
The amount of toner on the cleaning roller (3) is determined by the amount of toner supplied from the photosensitive drum (2). Therefore, the toner amount on the cleaning roller (3) is strongly influenced by the print pattern. That is, unevenness tends to occur in the circumferential toner layer thickness in the case of a short print pattern in the circumferential direction, and unevenness tends to occur in the axial toner layer thickness in the case of a print pattern biased in the axial direction.
As described above, when the toner layer thickness regulating roller (4) is rotated in contact with the cleaning roller (3) and the toner layer formed on the surface of the cleaning roller (3) is regulated, the portion where the toner layer thickness is thick takes precedence. Therefore, the difference between the thick and thin portions of the toner layer is reduced. Therefore, even if the amount of toner supplied to the cleaning roller (3) changes, a toner layer having a uniform thickness can be formed both in the circumferential direction and in the axial direction of the cleaning roller (3).
In addition, since both the cleaning roller (3) and the toner layer thickness regulating roller (4) hold toner, the surface layer is rubbed between the rollers covered with the toner, and the cleaning roller (3) and the toner layer thickness regulating roller Wear of (4) is prevented, and wear deterioration of the roller can be prevented even during long-term use.

As described above, 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).
However, when the printing rate is low or when monochrome printing is performed with a color copying machine, the amount of toner remaining on the surface of the photosensitive drum (2) is reduced, so that when the toner is scraped off by the cleaning blade (5), The amount of toner supplied from the body drum (2) to the cleaning roller (3) is also reduced, making it difficult to form a sufficiently thick toner layer on the cleaning roller (3).

Therefore, in the present invention, the toner receiving member (6) for storing the toner removed from the photosensitive drum (2) is installed below the cleaning roller (3). By doing so, the toner removed from the photosensitive drum (2) is not directly collected by the collecting screw (7), but is temporarily stored in the toner receiving member (6).
The toner stored in the toner receiving member (6) adheres to the cleaning roller (3) to form a toner layer.

The toner receiving member (6) is not particularly limited as long as the toner can be stored therein, and can be a flat plate or a bowl.
Examples of the material of the toner receiving member (6) include resins such as polyethylene terephthalate (PET) and polytetrafluoroethylene (PTFE), and metals such as aluminum (Al) and stainless steel (SUS). .

The toner receiving member (6) is disposed below the cleaning roller (3), and from the vicinity of the cleaning blade (5) to the downstream side in the rotation direction of the cleaning roller (3) (toner layer thickness regulating roller (4) side). (See FIGS. 1 to 3).
The toner removed from the photosensitive drum (2) by the cleaning blade (5) is not collected by the collecting screw (7) but is collected by the toner receiving member (6) to form a toner reservoir (not shown). . Even if the toner supply amount from the photosensitive drum (2) to the cleaning roller (3) decreases, the toner is supplied from this toner reservoir, and a toner layer can be formed on the cleaning roller (3). Become.

  In the cleaning device shown in FIG. 1, the toner receiving member (6) is longer from the vicinity of the cleaning blade (5) than the center position (broken line in FIG. 1) of the cleaning roller (3), and the cleaning roller (3) and the toner. It extends to a distance shorter than the position of the contact portion of the layer thickness regulating roller (4).

The toner layer thickness regulating roller (4) may be installed side by side in the horizontal direction of the cleaning roller (3), but it is preferable that the toner layer thickness regulating roller (4) is installed slightly below the cleaning roller (3) as shown in FIG. Specifically, the angle formed between the line connecting the center of the cleaning roller (3) and the center of the toner layer thickness regulating roller (4) and the line extending in the horizontal direction from the center of the cleaning roller (3) is greater than the horizontal direction. It is preferable to install it below the range of 30 to 60 °.
With such a configuration, it is possible to reduce the size of the cleaning device (1) and save space.

Further, the toner receiving member (6) is longer than the contact portion position (broken line in FIG. 2) of the cleaning roller (3) and the toner layer thickness regulating roller (4), and the central position of the toner layer thickness regulating roller (4). It may be extended to a shorter distance (see FIG. 2).
By adopting such a configuration, not only the toner removed from the photosensitive drum (2) but also the toner detached from the contact portion between the cleaning roller (3) and the toner layer thickness regulating roller (4) is received by the toner. It can be stored in the member (6).
Since the toner released from the contact portion between the cleaning roller (3) and the toner layer thickness regulating roller (4) is not collected by the collecting screw (7) but is temporarily collected in the toner receiving member (6), more toner Can be stored and supplied to the cleaning roller (3). Therefore, there is no possibility of running out of toner even if the amount of toner supplied from the photosensitive drum (2) decreases.

Further, the toner receiving member (6) may be extended to a distance slightly longer than the center position (broken line in FIG. 3) of the toner layer thickness regulating roller (4) (see FIG. 3).
With such a configuration, the toner removed from the photosensitive drum (2) and the toner detached from the contact portion between the cleaning roller (3) and the toner layer thickness regulating roller (4) are removed from the toner receiving member ( 6).
Further, since the toner receiving member (6) is extended to a distance slightly longer than the center position of the toner layer thickness regulating roller (4), a toner reservoir (not shown) is also provided below the toner layer thickness regulating roller (4). ) Can be formed.
Accordingly, the toner is stably supplied to the cleaning roller (3) for a longer period of time, and a uniform and sufficient thickness of the toner layer can be stably formed.

  The toner receiving member (6) is preferably installed at a distance of 0.5 to 3.0 mm from the surface of the cleaning roller (3). The toner receiving member (6) is fixed to the unit of the cleaning device (1), whereas the position of the cleaning roller (3) is not fixed because it is pressed against the photosensitive drum (2) by a spring. Therefore, the photosensitive drum (2) is likely to be affected by shake or the like due to rotation. Therefore, by installing the toner receiving member (6) in the above range, a sufficient amount of toner can be supplied without the cleaning roller (3) directly contacting the toner receiving member (6). If it is less than 0.5 mm, the cleaning roller (3) and the toner receiving member (6) may come into contact with each other. On the other hand, if the thickness exceeds 3.0 mm, the toner is accumulated in the toner receiving member (6), and it takes time until the toner is stably supplied from the toner receiving member (6) to the cleaning roller (3). There is a possibility that it does not adhere, and it is not preferable from the viewpoint of making the cleaning device (1) compact.

  As shown in FIG. 3, when the toner receiving member (6) is extended to a distance slightly longer than the center position of the toner layer thickness regulating roller (4), the toner layer thickness regulating roller (4) It is preferable to provide a gap that does not contact 6).

  The rotating directions of the photosensitive drum (2), the cleaning roller (3), and the toner layer thickness regulating roller (4) are preferably rotated in the same direction at the respective contact portions (indicated by arrows in FIGS. 1 to 3). By doing so, wear of each roller due to rubbing can be reduced as compared with the case of reverse rotation.

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 by the cleaning roller (3) to form a toner layer, which is adjusted to a uniform thickness by the toner layer thickness regulating roller (4). The surface of the photosensitive drum (2) is uniformly polished by the cleaning roller (3).

The material of the photosensitive drum (2) with which the cleaning roller (3) contacts is not particularly limited, and amorphous silicon, organic photosensitive member (OPC), or the like can be used. Further, when amorphous silicon is used, the outermost layer may be amorphous carbon or the like.
When the cleaning device (1) according to the present invention is used, even the photosensitive drum (2) made of amorphous silicon can be stably and sufficiently polished, and defective (image flow, dash marks, etc.) during image formation. ).

FIG. 4 is a schematic sectional view showing an 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) to be taken out, a manual feed tray (15) installed in front of the printer main body (11), and a manual paper feed unit (16) to take out paper (not shown) set in the manual feed tray (15) And a transport path (17) through which the paper supplied from each of the paper feed units (14) and (16) is transported, and a downstream side in the paper transport direction from the junction of the paper feed units (14) and (16) A pair of registration rollers (18) disposed in the image forming unit, an image forming unit (19) disposed downstream of the registration roller pair (18) in the sheet conveying direction, and a downstream side of the image forming unit (19) in the sheet conveying direction. Fixing an image (toner image) placed in And location (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 by a driving means (not shown) at a predetermined process speed (circumferential speed), and the surface thereof has a predetermined polarity by the charging device (23).・ Electrically charged to 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 laser light (not shown), removes the charge on the laser light irradiation portion of the surface of the photosensitive drum (2), and responds to the 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) on which the toner image is transferred to the sheet is freed of residual toner, discharge products, and the like by the cleaning device (1), and further charged by the charge eliminating device (not shown) during the next image formation. The static elimination process for 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.

  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 Cleaning blade 6 Toner receiving member

Claims (4)

A cleaning roller disposed in contact with the photosensitive drum; and a toner that is provided in contact with the photosensitive drum downstream of the cleaning roller in the rotational direction of the photosensitive drum and adheres to the surface of the drum. A cleaning device comprising a cleaning blade that scrapes off and a toner layer thickness regulating member that regulates the thickness of the toner layer adhered 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, the roller being slightly below the cleaning roller and viewed from the photosensitive drum in the rotation direction of the cleaning roller. Arranged downstream,
A toner receiving member that can supply the toner removed from the photosensitive drum by the cleaning blade to the cleaning roller is installed below the cleaning roller, and is located near the cleaning blade from the central position of the cleaning roller. A cleaning device that is long and extends to a distance shorter than a position where the cleaning roller and the toner layer thickness regulating roller contact each other . The photosensitive drum, the cleaning roller, the cleaning apparatus of claim 1, the rotation direction of the toner layer thickness regulating roller is equal to or in the same direction at the contact portion of each. The cleaning device according to claim 1 or 2, wherein the photosensitive drum is amorphous silicon. An image forming apparatus characterized in that it comprises a cleaning device according to any of claims 1 to 3.

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