JP4740669B2 - Image forming apparatus provided with cleaning device - Google Patents

Description

The present invention relates to an image forming apparatus such as a printer, a copying machine, and a facsimile machine that includes a cleaning device .

The electrophotographic process is composed of charging, exposure, development, transfer / fixing, and cleaning processes, and it is known that a blade cleaning system is usually employed in the final cleaning process (for example, Patent Document 1). reference).
In general, in the electrophotographic process, the surface of an image carrier that can be driven to rotate is uniformly charged by a charging device. The exposure optical system irradiates a laser beam to expose the surface of the image carrier to form an electrostatic latent image on the image carrier. Thereafter, the developer in the developing unit is moved to the surface of the image carrier to form a visible image on the image carrier.
Next, at a contact portion between the intermediate transfer device and the image carrier, a transfer belt provided inside the intermediate transfer device at the contact portion transfers a visible image on the surface of the image carrier to a transfer belt in the intermediate transfer device. Transfer to the surface.
The transferred developer is transferred onto the recording paper at the secondary transfer portion, and then supplied to the fixing device to fix the toner image on the recording paper. On the other hand, the developer remaining on the surface of the image carrier is removed by a cleaning blade in the cleaning device.
FIG. 9 is a schematic diagram illustrating a first example of a conventional cleaning device. FIG. 10 is a schematic diagram illustrating a second example of a conventional cleaning device. The blade 11a of the cleaning device 11 is obtained by attaching an elastic member 11b made of a material such as a plate-like polyurethane to a support 11d, and is configured to press and contact the surface of the electrophotographic photosensitive member 1.
As shown in FIG. 9, the first example of the cleaning device 11 includes a cleaning blade 11a in a casing so that the tip of the elastic member 11b can always come into contact with the photoreceptor 1 with a certain amount of biting. It is directly fixed to 11c.
As a result, a so-called fixed contact means is used in which the restoring force generated from the elastic deformation of the elastic member 11b is used as the blade pressing force. Reference numeral 11j denotes a conveying screw that conveys the collected toner.
In the second example of the cleaning device 11, as shown in FIG. 10, a pressing member 11k including a fulcrum shaft and a spring or the like on which a cleaning blade 11a can be rotated is provided on a part of the support 11d. Movable contact means is used to contact the surface of the photoreceptor 1 with a pressing force obtained from the member 11k. Reference numeral 11j denotes a transport roller for transporting the collected toner.
As described above, the conventional cleaning apparatus is roughly divided into two systems. However, since both types always apply a pressing force to the photoconductor, if the storage state or the unused state for a long time continues, the elastic blade may be deformed and the cleaning performance may be significantly impaired.
On the other hand, in the movable blade cleaning of the second example, an external contact / separation mechanism is provided to move between the contact / separation position by the position restricting member during storage, unused, and image formation. The measures are adopted.
Japanese Patent Laid-Open No. 06-138799

However, it is easy to increase the size of the device as a measure for suppressing blade permanent distortion at the time of storage, and it is difficult to apply it to recent small printers and MFPs, including the cost. Therefore, there is also a problem that the replacement life of the blade and the photoconductor is often set to be short.
Accordingly, an object of the present invention is to provide a blade for image formation and non-image formation by manipulating the rotation direction of the photosensitive member while the blade is always in contact with the photosensitive member without providing a separate separation / contact mechanism outside. An object of the present invention is to provide an image forming apparatus provided with a cleaning device capable of changing the contact position.

In order to solve the above problems, the invention described in claim 1 is a developer that remains on the image carrier after a visible image formed on the surface of the image carrier is transferred onto a recording paper or a transfer belt. In the image forming apparatus including the cleaning device for removing the cleaning material, the cleaning device supports the cleaning blade, and a cleaning blade including an elastic blade, a blade support member that fixes the elastic blade in the longitudinal direction, and the cleaning blade. The elastic blade tip of the cleaning blade includes a cleaning housing and is pivotally locked to the locking portion of the cleaning housing by round shaft portions provided at both ends of the blade support member. The cleaning blade is always in contact with the body surface and the cleaning housing includes the cleaning blade. On the other hand, a second restricting member provided on the downstream side in the forward rotation direction of the image carrier and a first restricting member provided on the upstream side are provided, and when the image is formed on the image carrier, the blade support member is The pressing force F against the image carrier generated in contact with the second restricting member, and the blade support member when the image carrier is rotated in the opposite direction to that at the time of image formation after completion of image formation. The pressing force F ′ against the image carrier that is generated in a state where the first contact member is in contact with the first restricting member has a relationship of F> F ′.
According to a second aspect of the present invention, there is provided an image forming apparatus comprising a cleaning device for removing a developer remaining on the image carrier after the visible image formed on the surface of the image carrier is transferred onto a recording paper or a transfer belt. The cleaning device includes an elastic blade, a cleaning blade including a blade support member that fixes the elastic blade in the longitudinal direction, and a cleaning housing that supports the cleaning blade. A shaft hole having the same hole center is provided at both ends of the support member, and the cleaning blade is rotatably engaged with the cleaning housing by a shaft passing through the shaft hole, and the image When the carrier is mounted, the tip of the elastic blade of the cleaning blade Always on the surface of the image bearing member abuts, and in the cleaning housing, first to said cleaning blade, is provided on the second regulating member and upstream provided in the normal rotation direction downstream side of said image bearing member And a pressing force F against the image carrier that is generated when the blade support member is in contact with the second restriction member when an image is formed on the image carrier. When the image carrier is rotated in the direction opposite to that at the time of image formation, the pressing force F ′ against the image carrier generated when the blade support member is in contact with the first regulating member is F> F 'relationship.
The invention of claim 3 is characterized in that, in claim 1 or 2, the rubber hardness used in the elastic blade is in the range of JIS-A 60 to 80 °.
According to a fourth aspect of the present invention, in the first, second, or third aspect, the resilience of the material used for the elastic blade is in the range of 10 to 60%.
According to a fifth aspect of the present invention, in any one of the first to fourth aspects, a brush roller that contacts the image carrier is arranged upstream of the cleaning blade in the positive rotation direction of the image carrier. And
According to a sixth aspect of the present invention, in any one of the first to fourth aspects, an elastic roller contacting the image carrier is disposed upstream of the cleaning blade in the normal rotation direction of the image carrier. Features.

  According to the present invention, since the frictional force acting between the photosensitive drum and the photosensitive drum is used, the pressing force of the blade can be achieved without being provided with a separate retraction mechanism. By reducing this, stable cleaning performance can be ensured even in long-term use.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 is a schematic configuration diagram of an image forming apparatus to which the present invention is applied. In FIG. 1, an image forming apparatus A has a photoconductive layer made of an organic material such as OPC on its surface, and has a plurality of photosensitive drums 1 that can rotate in forward and reverse directions.
Around each photosensitive drum 1, there are provided a charging roller 2, an exposure device 3, a developing device 4, and a cleaning device 11 for executing an image forming process along the positive rotation direction. The units are arranged in parallel for each color of Y, M, C, and Bk (hereinafter, only the Bk unit will be described as a representative).
The charging roller 2 is a conductive roller that can rotate in contact with the photosensitive drum 1. A DC voltage or a superimposed voltage of DC and AC is applied to the photoconductive layer of the photosensitive drum 1 by a high voltage power source. It is designed to be charged uniformly.
Thereafter, an electrostatic latent image is formed on the photosensitive drum 1 by the exposure device 3. In the developing device 4, for example, a contact one-component developing device that performs development by bringing a developing roller 4 a made of an elastic body into contact is used.
The toner 5 stored in the hopper 4c is supplied and conveyed onto the developing roller 4a via the supply roller 4b. After a toner thin layer is formed on the developing roller 4a by a regulating blade (not shown) in contact with the developing roller 4a, the electrostatic latent image is formed by contacting the electrostatic latent image on the photosensitive drum 1. Perform visible image processing.
In each color unit, the visible image formed on the photosensitive drum 1 sequentially moves onto the transfer belt 8a in the primary transfer portion, and a superimposed color image is formed on the transfer belt 8a.
The transfer device 8 includes a transfer belt 8a wound around a pair of rollers 8b and 8c including a drive roller 8b, a transfer bias roller 8d provided in the transfer belt 8a and facing each color photosensitive drum 1, a transfer belt A contact / separation mechanism (not shown) that enables 8a and transfer bias roller 8d to come into contact with the photosensitive drum 1 and a transfer belt 8a cleaning device including an elastic blade (not shown) are provided.
In the transfer device 8, a visible image on the photosensitive drum 1 is transferred onto the transfer belt 8a by applying a bias voltage from a transfer bias roller 8d via a high-voltage power supply (not shown).
Thereafter, the registration timing is set by a registration roller (not shown), and then a recording sheet (not shown) fed from a paper feeding device (not shown) is pressed against the roller of the transfer unit. The color image formed on the transfer belt 8a is transferred onto the recording sheet by holding it with the secondary transfer roller 9 set to be rotatable and applying a bias voltage to the secondary transfer roller 9 from a high voltage power source.
The recording paper on which the color image has been transferred by the secondary transfer roller 9 is conveyed to the fixing device 10 and discharged to a paper discharge tray (not shown).
Of the visible image formed on the photosensitive drum 1, the untransferred toner remaining on the photosensitive drum 1 without being transferred by the primary transfer is moved by the rotation of the photosensitive drum 1, and is cleaned by the cleaning device 11. Collected.
As shown in the conventional example, the cleaning device 11 includes a cleaning blade 11a mainly composed of a strip-shaped elastic blade 11b and a support member 11d that supports the elastic blade 11b, a conveying screw 11j that conveys the collected toner, and these. And a supporting housing (cleaning housing) 11c.

FIG. 2 is a schematic perspective view showing a first embodiment of the support member in the cleaning blade of the cleaning device according to the present invention. FIG. 3 is a schematic perspective view showing a second embodiment of the support member in the cleaning blade of the cleaning device according to the present invention. FIG. 4 is a schematic view showing a cleaning device according to the present invention.
In FIG. 2, the cleaning device 11 (see FIG. 1) is configured around a cleaning blade 11a comprising an elastic blade 11b and a blade support member 11d for adhering and fixing the elastic blade 11b in the longitudinal direction.
When the photosensitive drum (image carrier) 1 (see FIG. 1) is mounted, the tip of the elastic blade 11b is always in contact with the surface of the photosensitive drum 1, and round shafts are provided at both ends of the blade support member 11d of the cleaning blade 11a. The portion 11g can be formed or mounted.
The cleaning housing 11c (see FIG. 1) is provided with a locking portion (not shown) that locks the round shaft portions 11g at both ends of the blade support member 11d, which enables the cleaning blade 11a to be positioned and rotated. .

In the second embodiment of the support member in the cleaning blade of the cleaning device according to the present invention in FIG. 3, the cleaning device 11 (see FIG. 1) is bonded and fixed to the elastic blade 11b and the elastic blade 11b in the longitudinal direction. The cleaning blade 11a is composed of a supporting member 11d.
When the photosensitive drum (image carrier) 1 (see FIG. 1) is mounted, the tip of the elastic blade 11b is always in contact with the surface of the photosensitive drum 1. Shaft holes 11f are provided at both ends of the blade support member 11d of the cleaning blade 11a so that a rotating shaft (not shown) can penetrate along with the cleaning housing 11c (see FIG. 1).
The rotating shaft 11g in FIG. 2 is locked to a predetermined portion of the cleaning housing 11c. That is, as shown in FIG. 4, both walls of the slit portion 11i of the blade support member 11h provided at an interval narrower than the outer diameter of the rotating shaft 11g are bent and enlarged. During this time, after passing the rotating shaft 11g and the blade support member 11d, the cleaning blade 11a is mounted on the housing in a state where it can rotate around the rotating shaft 11g by being locked by reaching a predetermined locking portion 11e. Is done. In other words, the blade support member 11h has two openable and closable walls having a locking portion 11e that supports the rotary shaft 11g in a rotatable manner, and rotates while pressing and expanding the two walls. The shaft 11b can be seated on the locking portion 11e by press-fitting the shaft 11b.

FIG. 5 is a schematic view showing members for regulating the cleaning blade of the cleaning device according to the present invention. In FIG. 5, the cleaning housing 11c is upstream of the rotation direction of the photosensitive drum 1 with respect to the cleaning blade so that the whole or a part of the cleaning support member 11d is sandwiched at a predetermined interval in the longitudinal direction of the photosensitive drum 1. The 1st control member 13 provided in this and the 2nd control member 12 provided in the downstream are formed.
These first and second restricting members 13 and 12 are provided at appropriate positions on the cleaning housing 11c at a predetermined interval, and restrict the rotational movement of the cleaning blade 11a.
When the photosensitive drum 1 forms an image, the cleaning blade 11a in contact therewith rotates about the round shaft portion 11g by the clockwise rotation of the photosensitive drum 1 in the direction of the charging roller 2.
The pressing force F applied to the photosensitive drum 1 generated when the blade support member 11d is in contact with the second restricting member 12, and the image carrier (photosensitive drum) 1 after the image formation is reversed. The pressing force F ′ against the image carrier 1 generated when the cleaning support member 11d is in contact with the first restricting member 13 when rotated in the direction is configured to satisfy the relationship of F> F ′. The
When the photosensitive drum 1 is mounted, the tip of the elastic blade 11b is always in contact with the photosensitive drum 1 and elastically deformed with the cleaning blade 11a. During image formation, the cleaning blade 11a rotates the photosensitive drum 1 due to the frictional force generated at the contact portion of the surface of the photosensitive drum 1 and the cleaning blade 11a (the tip of the elastic blade 11b) as the photosensitive drum 1 rotates. Rotation in the direction is started, and the second restrictor 12 and the cleaning blade support member 11d are moved to a position where they abut and are fixed.
In the present invention, without providing a separate separation / contact mechanism outside, the elastic blade 11b is always in contact with the photosensitive drum 1, but the rotational direction of the photosensitive drum 1 is operated to form an image (during normal rotation). ) And during non-image formation (reverse rotation), the contact position of the elastic blade 11b is changed to reduce the pressing force during non-image formation, thereby suppressing permanent deformation of the elastic blade 11b.
FIG. 6 is a schematic diagram showing the amount of biting into the photosensitive drum at the tip of the elastic blade. At the position determined by the second restricting portion 12, the tip of the elastic blade 11 b is set to have a desired amount of biting into the photosensitive drum 1.

5 and 6, the tip of the elastic blade 11b is further elastically deformed with the rotation by the frictional force, and the blade pressing force F from the cleaning blade 11a generated in the fixed state to the surface of the photosensitive drum 1 is the photosensitive drum 1. It is set as a blocking force sufficient to block the transfer residual toner from passing above.
Residual toner on the photosensitive drum 1 that has been blocked from passing by the cleaning blade 11a is transported and collected as a waste toner to a predetermined location in the apparatus. Further, during non-image formation, the photosensitive drum 1 is rotated reversely by a predetermined angle, whereby the cleaning blade 11a rotates about the rotation shaft (round shaft portion) 11g in the opposite direction to that during image formation. 1 Moves to a position where it comes into contact with and rests on the restricting portion 13.
Even at this position, the tip of the elastic blade 11b of the cleaning blade 11a maintains the biting amount with respect to the photosensitive drum 1, and comes into contact with the photosensitive drum 1 while maintaining a predetermined blade pressing force F ′.
Note that the photosensitive drum at the position of the first restricting portion 13 is such that the blade pressing force F ′ generated at the position of the first restricting portion 13 is smaller than the blade pressing force F generated at the position of the second restricting portion 12. The blade biting amount to 1 is set to be smaller than the blade biting amount to the photosensitive drum 1 at the second restricting portion 12 position.
Actually, it is desirable that the blade pressing force F necessary for preventing and collecting the passing of the residual toner is set in the range of 10 to 60 (N / m). In this way, by utilizing the frictional force generated between the elastic blade 11b and the photosensitive drum 1, there is no need to separately provide a conventionally used pressing member such as a spring or a blade separation mechanism, and the size and cost can be reduced. It is possible to provide a cleaning device.
In addition, since the elastic deformation is maintained in a smaller state during non-image formation, permanent distortion generated in the elastic blade 11b can be suppressed for a long time, and stable image supply is possible.

As described with reference to FIG. 4, in the cleaning device 11 of the present invention, the round shaft portions 11g are mounted (projected) at both ends of the support member 11d of the cleaning blade 11a, and the slits have end portions in the housing 11c. It has a latching part 11e that allows the rotating shaft 11g to pass through while expanding the open passing part and fixes the cleaning blade 11a to be rotatable.
Further, in this case, instead of mounting the rotating shaft (round shaft portion) 11g on both ends of the support member 11d of the cleaning blade 11a, a concentric shaft hole 11i is provided to provide the same diameter provided in the housing 11c. The shaft hole (not shown) and one rotating shaft (not shown) can be locked and held.
In addition, first and second restricting members 13 and 12 for restricting the rotational movement of the locked cleaning blade 11a are provided in the housing 11c on the upstream side and the downstream side in the rotational direction of the photosensitive drum 1. .
The cleaning blade 11a is always in contact with the photosensitive drum 1, and when the photosensitive drum 1 is driven, the cleaning blade 11a is rotated by the frictional force acting on the contact portion (elastic blade 11b), and the downstream side regulation is performed. It strikes against the member (second regulating member) 12 and stops, and the blade linear pressure generated at this time blocks the passage of residual toner.
Further, when the non-image is formed, the cleaning blade 11a is rotated in the reverse direction and brought into contact with the upstream side regulating member (first regulating member) 13 so as to be retracted to a position where the linear pressure is lower when not in operation.
The material of the elastic blade 11b used for the cleaning blade 11a is preferably 60 to 80 in hardness [JIS-A type], 10 to 60% in rebound resilience, 300 to 350% in elongation, and 1. Those having 0 to 5.0% and 300% modulus in the range of 100 to 350 kg / cm ² are used.
In the cleaning, the hardness of the elastic blade 11b is an important parameter in controlling the contact state with the photosensitive drum 1. By using one having a hardness in the range of 60 to 80 °, a stable contact angle with respect to the photosensitive drum 1 can be obtained, so that cleaning performance without residual wiping of residual toner can be obtained.
By using the elastic blade 11b having a rebound resilience of 10 to 60%, unnecessary vibration at the cleaning blade 11a contact portion (elastic blade 11b) is absorbed and stable contact is obtained. Cleaning performance without wiping off is obtained.
Conventionally, a resin conventionally used in plate blade members, for example, urethane, styrene, olefin, vinyl chloride, polyester, polyamide, fluorine resin, etc. Can do.

FIG. 7 is a schematic view showing another embodiment of the cleaning device according to the present invention. In the embodiment of FIG. 7, the brush roller 14 is disposed upstream of the cleaning blade 11 a in the positive rotation direction of the photosensitive drum 1. In the figure, 11c is a cleaning housing, 11d is a blade support member, and 11h is a second blade support part.
The residual toner is partially collected or removed before reaching the contact portion (elastic blade 11b) of the cleaning blade 11a by applying a rotational rubbing and bias voltage to the photosensitive drum 1 using the brush roller 14. Therefore, it is possible to reduce the pressing force of the cleaning blade.
As materials used for the brush, nylon, acrylic and rayon are the main materials, and the fiber thickness is 2-8 denier, the density is 50,000-300000 per inch square, and the electric resistance value is 10 8 Ω or less. be able to.
As the bias voltage applied to the photosensitive drum, a DC voltage or a DC voltage superimposed on an AC component is used. By applying the bias voltage, an effect of reducing the adhesion force of the residual toner to the photosensitive member due to electrical recovery or vibration of an alternating electric field can be obtained, and the elastic blade 11b of the cleaning blade 11a can be easily scraped off.
By providing the brush roller 14 upstream of the cleaning blade 11a, the total amount of toner entering the contact portion (elastic blade 11b) of the cleaning blade 11a can be reduced in advance, or static electricity can be reduced by applying voltage to reduce adhesion. Therefore, it is possible to reduce the pressing force of the cleaning blade, and it is possible to extend the service life.

FIG. 8 is a schematic view showing a modification of the cleaning device according to another embodiment of the present invention shown in FIG. In this modification, instead of the brush roller 14, an elastic roller 15 having NBR, EPDM, or urethane as a main component and having an electric resistance value of 10 ⁸ Ω or less is used.
In the figure, 11a is a cleaning blade, 11b is an elastic blade, 11c is a cleaning housing, 11d is a blade support member, and 11h is a second blade support portion.
By bringing the elastic roller 15 into contact with the surface of the photosensitive drum 1 while applying a bias voltage, it is possible to obtain the same effect as that of a brush roller. By applying a bias voltage to the elastic roller 15, it is possible to extend the service life by reducing the adhesive force due to the residual toner neutralizing effect.

1 is a schematic configuration diagram illustrating a configuration of an image forming apparatus to which the present invention is applied. It is a schematic perspective view which shows 1st Embodiment of the supporting member in the cleaning blade of the cleaning apparatus by this invention. It is a schematic perspective view which shows 2nd Embodiment of the supporting member in the cleaning blade of the cleaning apparatus by this invention. It is the schematic which shows the cleaning apparatus by this invention. It is the schematic which shows the member which controls the cleaning blade of the cleaning apparatus by this invention. It is the schematic which shows the biting amount with respect to the photosensitive drum of the elastic-body blade front-end | tip. It is the schematic which shows other embodiment of the cleaning apparatus by this invention. It is the schematic which shows the modification of other embodiment of the cleaning apparatus by this invention of FIG. It is the schematic explaining the 1st example of the conventional cleaning apparatus. It is the schematic explaining the 2nd example of the conventional cleaning apparatus.

Explanation of symbols

A Image forming apparatus 1 Image carrier (photosensitive drum)
2 Charging device (charging roller)
DESCRIPTION OF SYMBOLS 3 Exposure apparatus 4 Developing apparatus 5 Developer 8 Transfer apparatus 8a Transfer belt 11 Cleaning apparatus 11a Cleaning blade 11b Elastic body blade 11c Cleaning housing 11d Blade support member 11e Locking part 11f Shaft hole 11g Round shaft part (rotating shaft)
11h Second blade support member 11i Slit portion 12 Second restriction member 13 First restriction member 14 Brush roller 15 Elastic roller

Claims (6)

In an image forming apparatus comprising a cleaning device for removing a developer remaining on the image carrier after transferring a visible image formed on the surface of the image carrier on a recording paper or a transfer belt,
The cleaning device includes an elastic blade, a cleaning blade including a blade support member that fixes the elastic blade in the longitudinal direction, and a cleaning housing that supports the cleaning blade.
The tip of the elastic blade of the cleaning blade, which is pivotally locked to the locking portion of the cleaning housing by round shaft portions provided at both ends of the blade support member, always contacts the surface of the image carrier. The cleaning housing is provided with a second regulating member provided on the downstream side in the forward rotation direction of the image carrier and a first regulating member provided on the upstream side with respect to the cleaning blade,
At the time of image formation of the image carrier, the pressing force F against the image carrier generated when the blade support member is in contact with the second regulating member, and the image carrier is formed after the image formation is completed. The pressing force F ′ applied to the image carrier when the blade support member is in contact with the first restricting member when rotated in the opposite direction to the time is expressed as F> F ′. An image forming apparatus . In an image forming apparatus comprising a cleaning device for removing a developer remaining on the image carrier after transferring a visible image formed on the surface of the image carrier on a recording paper or a transfer belt,
The cleaning device includes an elastic blade, a cleaning blade including a blade support member that fixes the elastic blade in the longitudinal direction, and a cleaning housing that supports the cleaning blade.
A shaft hole having the same hole center is provided at both ends of the blade support member of the cleaning blade, and the cleaning blade is rotatably engaged with the cleaning housing by a shaft passing through the shaft hole. In addition, when the image carrier is mounted, the tip of the elastic blade of the cleaning blade is always in contact with the surface of the image carrier, and the cleaning housing holds the image with respect to the cleaning blade. A second restricting member provided on the downstream side in the forward rotation direction of the carrier and a first restricting member provided on the upstream side;
At the time of image formation of the image carrier, the pressing force F against the image carrier generated when the blade support member is in contact with the second regulating member, and the image carrier is formed after the image formation is completed. The pressing force F ′ applied to the image carrier when the blade support member is in contact with the first restricting member when rotated in the opposite direction to the time is expressed as F> F ′. An image forming apparatus . 3. The image forming apparatus according to claim 1, wherein the rubber hardness used for the elastic blade is in a range of JIS-A 60 to 80 [deg.]. The image forming apparatus according to claim 1, wherein the resilience of the material used for the elastic blade is in the range of 10 to 60%. 5. The image forming apparatus according to claim 1, wherein a brush roller that is in contact with the image carrier is disposed upstream of the cleaning blade in the positive rotation direction of the image carrier. 5. The image forming apparatus according to claim 1, wherein an elastic roller that is in contact with the image carrier is disposed upstream of the cleaning blade in the positive rotation direction of the image carrier.

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