JPH09114201A - Image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an image forming device constituted so that the electrostatic charge means can be effectively cleaned. SOLUTION: This image forming device is constituted so that a first cleaning means 6 is disposed to abut on the electrostatic charge means 2 and a voltage whose polarity is identical to a DC voltage impressed on the charge means 2 and whose absolute value is larger than the DC voltage impressed on the charge means 2 is impressed on the cleaning means 6. OR a second cleaning means 6 is disposed to abut on the charge means 2 and constituted of a brush so that the biting depth D thereof with respect to the charge means 2 is set to be >=0.1mm and <=1.2mm.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrophotographic image forming apparatus such as a copying machine or a laser printer, and more particularly to charging an image carrier or a toner image formed on the image carrier. The present invention relates to an improvement of an image forming apparatus having a charging unit used when transferring or the like.

Conventionally, this type of electrophotographic image forming apparatus is arranged, for example, in contact with an image bearing member such as a photosensitive drum, and the charging voltage is applied between the image bearing member. A charging roll for uniform charging that is applied, an exposing unit that exposes the image bearing member to form a latent image, a developing unit that develops the latent image to form a toner image, and abutting against the image bearing member. The transfer charging roller is arranged and a transfer voltage is applied to the image carrier. In the image forming apparatus, first, the charging roller for uniform charging charges the image carrier to a uniform charging potential, the exposing unit forms a latent image on the image carrier, and the developing unit develops the latent image. Is developed to form a toner image on the image carrier, and then the toner image is transferred onto a transfer material such as a recording sheet by a transfer charging roll to form an image on the transfer material. It is a thing.

However, in the charging means such as the charging roller for uniform charging and the charging roller for transfer, as the image formation is repeated, dirt such as toner adheres to the surface. Since the charging means realizes the above-mentioned function by adhering discharge-generated ions, electrons, etc. to the image bearing member or the transferred material in accordance with the applied voltage, the stains cause an electric resistance such as a resistance value. Characteristics change. As a result, in the image forming apparatus, the charge amount that can be attached to the image bearing member or the transferred member is changed by the charging unit, the charging potential of the image bearing member and the transfer efficiency are changed, and the image density is increased. Image quality defects such as fluctuations occur.

Particularly, in the charging means in which only the DC voltage is applied as the applied voltage, the dirt is not only attached by the physical adhesive force but also by the electrostatic adhesive force. As compared with the charging means applied with the above-mentioned applied voltage, a large amount of dirt adheres strongly, and the life of the charging means becomes 1/10 or less.

[0005]

2. Description of the Related Art A technique for removing dirt from the surface of the charging means by bringing a cleaning means having a felt or web into a pad shape into contact with the surface of the charging means is known.
It is disclosed in JP-A-301777, JP-A-2-301779, JP-A-6-202447 and the like.

However, in the technique of the above publication, since the dirt is removed by the mechanical rubbing force obtained by simply bringing the cleaning means into contact with the surface of the charging means, the cleaning ability of the cleaning means is low. However, it was not possible to sufficiently remove a large amount of dirt that strongly adhered electrostatically to the charging means to which only the DC voltage was applied.

Further, since the cleaning means of the above-mentioned publication has a low cleaning ability, it is deformed before removing the dirt, and thus the dirt is deformed to form a film-like film on the surface of the charging means. Resulting in. Note that this phenomenon is generally called filming. Then, the filmed stain cannot be removed by the cleaning means.

[0008]

SUMMARY OF THE INVENTION Therefore, it is an object of the present invention to provide an image forming apparatus capable of effectively cleaning the charging means.

[0009]

That is, the first invention of the present application is to provide an image carrier on which a toner image is formed, and a charging device which is arranged in contact with or close to the image carrier and to which a DC voltage is applied. An image forming apparatus for forming an image on a recording medium by means of an electrophotographic method, the cleaning means is provided in contact with the charging means, and the cleaning means is applied to the charging means. The image forming apparatus applies a voltage having the same polarity as the DC voltage and an absolute value larger than that of the DC voltage applied to the charging unit. In the following description, the cleaning means will be referred to as the first cleaning means.

The second invention of the present application has an image carrier on which a toner image is formed, and a charging means which is disposed in contact with or close to the image carrier and to which a voltage is applied. In an image forming apparatus that forms an image on a recording medium by a photographic method, a cleaning unit is provided in contact with a charging unit, and
The cleaning unit is an image forming apparatus that is composed of a brush and has a depth of biting into the charging unit of 0.1 mm or more and 1.2 mm or less. In the following description, the cleaning means will be referred to as the second cleaning means.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION In the present invention, the charging means is arranged in contact with or in close proximity to the image bearing member, and a voltage is applied to discharge the discharge-generated ions or electrons from the image bearing member or the transferred object. Any material that can be attached to the body may be used, and examples thereof include a uniform charging roller and a transfer charging roller.

The first cleaning means is capable of rubbing the charging means when it is placed in contact with the charging means and forming an electric field between the charging means and the charging means when a voltage is applied. It may be any structure, for example, a contact member arranged in contact with the charging means and a conductive base material supporting the contact member. The shape of the first cleaning means may be, for example, a pad shape, a roll shape, or a blade shape. Furthermore, in order to maintain the cleaning ability, the first cleaning means is, for example, formed in a roll shape and rotatably arranged, or for winding a long web between a pair of winding rolls. Alternatively, the portions contacting the charging means may be replaced with each other.

The abutting member may be any member as long as it can rub against the charging means when it is provided in contact with the charging means.
Examples include brushes, webs, felts and the like. Further, the contact member may be conductive or insulative.

The first cleaning means of the first invention applies a mechanical rubbing force and an electrostatic attraction force to dirt adhering to the charging means to which a DC voltage is applied. You can

By the way, in the above-mentioned first invention, when the first cleaning means is entirely made of a conductive material, an electric current flows in a contact portion between the first cleaning means and the charging means. Since the electric field may not be formed between the first cleaning unit and the charging unit in some cases, it is necessary to adjust the contact area between the first cleaning unit and the charging unit. For example, when the first cleaning means is made of a conductive brush, the depth of biting of the brush into the charging means is 1.4 m.
It may be adjusted so as to be m or less. The bite depth is, for example, when the first cleaning means is made of a conductive brush roll and the charging means is made of a charging roll, the radius of the brush roll before contact and the radius before contact It is a value obtained by subtracting the distance between the center of the brush roll and the center of the contact charging roll from the sum of the radius of the charging roll, and the contact area between the first cleaning means and the charging means becomes deeper as the biting depth becomes deeper. There is a growing relationship.

Further, in the above-mentioned first invention, the voltage applied to the first cleaning means has the same polarity as the DC voltage applied to the charging means, and is more absolute than the DC voltage applied to the charging means. Is a large voltage, but preferably,
The difference in absolute value from the DC voltage applied to the charging means is 200V
It is better to set the voltage to 3000 V or less. Because, if the potential difference is less than 200V,
The effect of improving the cleaning ability due to the electrostatic attraction does not significantly appear, and when the potential difference exceeds 3000 V, spark discharge occurs between the first cleaning means and the charging means, and This is because the first cleaning means will melt.

Further, in the above-mentioned first invention, when the potential difference between the voltage applied to the first cleaning means and the DC voltage applied to the charging means is increased, the first cleaning means flows to the charging means. Since the current increases, it becomes impossible to ignore the effect on the image due to the electric charges that the first cleaning unit attaches to the image carrier or the transfer target through the charging unit. In that case, a voltage may be applied to the first cleaning unit when the charging unit is not performing the image forming operation. Further, when the image forming operation by the charging means is not performed, for example, in the case of the uniform charging means, the image area of the image carrier on which the toner image is formed is not charged by the charging means. The time means, for example, the period from when the inter-image area of the image bearing member faces the charging unit to when the image forming operation is started after the image forming operation is instructed. ,
Immediately after the image forming operation is finished, immediately after turning on the power of the apparatus, when the door of the apparatus is opened / closed to replenish toner or remove jammed paper, the power of the apparatus is temporarily turned off (so-called interlock (When releasing) etc.

The second cleaning means may be formed in a brush shape, and the length of each brush fiber may exceed 1.2 mm. For example, a conductive brush roll may be used.
Further, the second cleaning means may be conductive or insulative.

The second cleaning means is arranged in contact with the charging means so that the depth of the bite into the charging means is 0.1 mm or more and 1.2 mm or less.

The second cleaning means of the second invention is
A high rubbing force can be applied to the dirt attached to the charging means.

In the second aspect of the invention, when the second cleaning means and the charging means are rotatable, the sliding friction force becomes too large when the speed difference between the moving speeds of their surfaces becomes large. On the contrary, filming may occur on the charging means. In such a case, the moving speed of the surface of the second cleaning means at the position where the second cleaning means and the charging means contact each other is V _1, and the moving speed of the surface of the charging means at the contact position is V ₂ If you do, V ₁
It is preferable to adjust / V _{2 to} be 1 or more and 2 or less.
For example, when the second cleaning unit is a brush roll and the charging unit is a charging roll, the linear velocity of the peripheral surface of the brush roll is V ₁ and the linear velocity of the peripheral surface of the charging roll is V _2.
Then, V ₁ / V ₂ may be adjusted to 1 or more and 2 or less.

In the second aspect of the present invention, the weft density of the second cleaning means is preferably 30,000 or more / inch ^{2 and not} more than 130,000 / inch ² . If the weaving density is less than 30,000 filaments / inch ² , the cleaning ability of the entire brush will be low even if the cleaning ability of each brush fiber is present.

Next, in the second aspect of the present invention, the length of each brush fiber may be more than 1.2 mm, preferably 2.0 mm or more and 15 mm or less. When the length exceeds 15 mm, a part of the dirt remains on the charging means even if there is a rubbing force, and the dirt is repeatedly pressed against the photoconductor and the charging means. Mingling cannot be prevented. If the length is less than 2.0 mm, the rubbing force on the charging means becomes too large, and filming may occur.

Further, in the second invention, the diameter of each brush fiber may be at least 10 μm or more and 60 μm or less.

In the first and second aspects of the invention, if dirt is accumulated on the cleaning means itself, the dirt will be reattached to the charging means, so that the dirt is collected from the cleaning means. It is advisable to provide a dirt collecting unit for maintaining the cleaning ability of the cleaning unit. The dirt collecting means may be any one that can remove dirt adhering to the cleaning means. For example, when the cleaning means is a brush roll, a flicker bar or the like arranged so as to contact brush fibers is used. it can.

[0026]

Embodiments of the present invention will be described below with reference to the accompanying drawings.

Embodiment 1 FIG. 1 shows an electrophotographic image forming apparatus according to Embodiment 1 of the present invention. This image forming apparatus includes a photosensitive drum 1,
It has a charging means 2 arranged around it, an exposing means (not shown), a developing means 3, a transfer means 4, and a photoconductor cleaning means 5.

The photosensitive drum 1 is an organic photosensitive member having an outer diameter of 84 mm and an axial length of 350 mm, and has a circumferential surface of 30 mm.
It is rotated so as to move at a linear velocity of 0 mm / s.

The charging means 2 comprises a contact charging roll formed by disposing an elastic body 2b around a stainless steel shaft 2a having a diameter of 8 mm and having an outer diameter of 14 mm and an axial length of 330 mm. When a charging voltage of -1350V (DC) is applied between the shaft 2a and the photoconductor 1, a minute gap discharge is performed between the shaft 2a and the photoconductor 1 to make the photoconductor 1 uniform at -750V. It is one that is charged. Further, the contact charging roll 2 is arranged in contact with the photoconductor 1 so as to rotate following the rotation of the photoconductor 1.

The exposing means comprises, for example, a laser light emitting element which emits light according to image information and a polygon mirror which reflects the laser light, and exposes the photosensitive body 1 charged to a uniform potential to expose the photosensitive body. An electrostatic latent image is formed on the surface 1.

The developing means 3 has a developing roll 3a arranged so as to face the photoconductor 1, and a developing voltage of -600V (DC) is applied between the developing roll 3a and the photoconductor 1. As a result, the electrostatic latent image is developed with negatively charged toner to form a toner image on the photoconductor 1.

The transfer means 4 comprises a contact transfer roll arranged in contact with the photoconductor 1, and transfers a toner image by passing a transfer current of +25 μA from the transfer roll 4 toward the photoconductor 1. Is.

The photoconductor cleaning means 5 has a blade arranged in contact with the photoconductor 1, and the blade cleans the peripheral surface of the photoconductor 1 by removing residual toner on the photoconductor 1. Is.

Then, the image forming apparatus forms an image on the recording sheet by electrophotography. Specifically, in the image forming apparatus, first, the charging unit 2 charges the photosensitive member 1 to a uniform potential, the exposing unit forms an electrostatic latent image on the photosensitive member 1, and the developing unit 3 causes the electrostatic latent image to be formed. The latent image is developed to form a toner image on the photoconductor 1. Next, in the image forming apparatus, the photoconductor 1
By supplying a recording sheet between the photoconductor 1 and the transfer unit 4 and flowing the transfer current at the timing when the toner image rotates between the transfer unit 4 and the transfer unit 4,
The toner image on the photoconductor 1 is attracted to the recording sheet side to form an image on the recording sheet.

In this embodiment, as shown in FIG. 2, the charging roll cleaning means 6 for cleaning the contact charging roll 2 is provided in the image forming apparatus.

The charging roll cleaning means 6 is a conductive brush roll 6a in which a brush is wound around a conductive shaft. The above-mentioned brush is formed by knitting a large number of conductive brush fibers made of polypropylene having a length of 6.5 mm and a diameter of 25 μm at a weave density of 60,000 / inch ² .

In this embodiment, the conductive brush roll 6a is arranged in contact with the contact charging roll 2 so that the bite depth of the contact charging roll 2 is 0.4 mm. The bite depth is a value obtained by subtracting the distance between the center of the brush roll 6a and the center of the contact charging roll 2 from the sum of the radius of the brush roll 6a before contact and the radius of the charging roll 2 before contact. Is. Further, in this embodiment, when the linear velocity of the peripheral surface of the brush roll 6a is V ₁ and the linear velocity of the peripheral surface of the charging roll 2 is V ₂ , V ₁ / V ₂ is 1.6. The brush roll 6a was rotated. Further, in this embodiment, as shown in FIG. 3, after the blind switch is pressed A, when the inter-image portion when images are continuously formed faces the contact charging member B, When a series of image forming operations by the switch is completed, the shaft of the conductive brush roll 6a is set to -3000V (D
The cleaning voltage of C) was applied.

When a black band image having a width of 1 cm was formed continuously on the image forming apparatus once every 6 seconds for 1 hour, a large amount of dirt adhered to the conductive brush roll 6a. It was found that the surface of the contact charging roll 2 was not contaminated and the conductive brush roll 6a had a high cleaning ability. Further, after the above experiment, when the surface of the contact charging roll 2 was examined in detail, no filmed stain was attached to the surface of the contact charging roll 2. Further, after the above experiment, when the dirt attached to the conductive brush roll 6a was examined, it was found that electrostatically adhered to the conductive brush roll 6a and mechanically adhered to the brush roll 6a. there were.

As can be seen from FIG. 3, when the cleaning voltage is applied, the surface potential of the contact charging roll 2 and thus the charging potential of the photoreceptor 1 becomes higher than desired. Therefore, as described above, the cleaning potential may be applied when the contact charging roll 2 does not charge the area on the photoconductor 1 for forming the toner image.

Further, in the present embodiment, the present invention is applied to the image forming apparatus in which the charging means 2 has one contact charging roll. However, as shown in FIG. 4, the charging means 2 has two contact charging rolls 7a. , 7b may be applied to the present invention. Further, in this embodiment, the conductive brush roll 6 is used.
Although the charging roll cleaning means 6 made of a is arranged so as to contact the contact charging roll 2, as shown in FIG. 5, the charging roll cleaning means 6c made of a take-up web and a conductive roll is used as the charging roll cleaning means 6c. Even if the contact charging roll 2 is arranged so as to come into contact with the web via the web, as shown in FIG.
Even if the charging roll cleaning means composed of the conductive pad 6d is arranged so as to contact the contact charging roll 2, as shown in FIG. 7, the charging roll cleaning means composed of the conductive roller 6e contacts the contact charging roll 2. Even if it is arranged as described above, as shown in FIG. 8, the same result can be obtained even if the charging roll cleaning means composed of the conductive blade 6f is arranged so as to contact the contact charging roll 2.

Embodiment 2 In this embodiment, the cleaning voltage is from -500V to -4350V.
The same experiment as in Example 1 was performed by changing the above.

As a result, as shown in FIG. 9, there is a potential difference between the charging voltage applied to the contact charging roll 2 and the voltage of 200V.
When a cleaning voltage of 1550 V or higher was applied, sufficient cleaning ability of grade 2 or higher was obtained. When a cleaning voltage of −4350V, which is a potential difference of 3000V from the charging voltage applied to the contact charging roll 2, is applied, spark discharge occurs between the conductive brush roll 6a and the contact charging roll 2. The conductive brush roll 6a and the contact charging roll 2 have melted. From the above, it was found that if the potential difference between the cleaning voltage and the charging voltage is 200 V or more and 3000 V or less, sufficient cleaning ability can be obtained without causing secondary problems.

Example 3 In this example, the same experiment as in Example 1 was conducted by changing the depth of penetration of the conductive brush roll 6a into the contact charging roll 2 from 0 mm to 1.6 mm.

As a result, as shown in FIG. 10, unless the biting depth is 1.4 mm or less, the potential difference between the potential of the conductive brush roll 6a and the potential of the contact charging roll 2 is 20.
It could not be maintained at 0 V or higher, that is, an appropriate electric field could not be formed between the conductive brush roll 6a and the contact charging roll 2, and sufficient cleaning ability of grade 2 or higher could not be obtained. From the above, the conductive brush roll 6
It was found that a sufficient cleaning ability can be obtained by setting the depth of the bit a into the contact charging roll 2 to 1.4 mm or less.

Example 4 In this example, the same experiment as in Example 1 was carried out by changing the depth of penetration of the conductive brush roll 6a into the contact charging roll 2 from 0 mm to 1.4 mm.

As a result, as shown in Table 1, when the bite depth was 0.1 mm or more and 1.2 mm or less, sufficient cleaning ability was obtained and filming could be prevented. From the above, the depth of penetration of the conductive brush into the contact charging roll is 0.1 mm or more and 1.2 mm.
It was found that sufficient cleaning ability can be obtained while preventing filming if the following is done.

[0047]

[Table 1]

Example 5 In this example, when the linear velocity of the peripheral surface of the conductive brush roll 6a is V ₁ and the linear velocity of the peripheral surface of the contact charging roll 2 is V ₂ , V ₁ / V ₂ Was changed from 0.8 to 2.0 and the same experiment as in Example 1 was performed.

As a result, as shown in Table 2, the speed ratio V ₁
When / V ₂ was 0.8, filming occurred. From the above, the speed ratio V ₁ / V ₂ is at least 2.0 or less, 1.
It was found that if it is 0 or more, sufficient cleaning ability can be obtained while preventing the occurrence of filming.

[0050]

[Table 2]

Example 6 In this example, the weave density of the conductive brush roll 6a was set to 1
The same experiment as in Example 1 was conducted by changing the number from 30,000 to 130,000 / inch ² .

As a result, as shown in Table 3, in all cases, the cleaning ability could be improved while preventing the occurrence of filming. From the above, the bristle density of the conductive brush roll 6a is at least 10,000 /
It has been found that if it is not less than ² inch and not more than 130,000 / inch ² , then sufficient cleaning ability can be obtained while preventing the occurrence of filming.

[0053]

[Table 3]

Example 7 In this example, the same experiment as in Example 1 was conducted by changing the length of each brush fiber of the conductive brush roll 6a from 2.0 to 20 mm.

As a result, as shown in Table 4, filming occurred at a length of 20 mm. From the above, it was found that if the length of each brush fiber of the conductive brush roll 6a is at least 2.0 mm or more and 15 mm or less, sufficient cleaning ability can be obtained while preventing the occurrence of filming.

[0056]

[Table 4]

Example 7 In this example, the same experiment as in Example 1 was conducted by changing the diameter of each brush fiber of the conductive brush roll 6a to 10 to 60 μm.

As a result, as shown in Table 5, in all cases, the cleaning ability could be improved while preventing the occurrence of filming. From the above, the diameter of each brush fiber of the conductive brush roll 6a is at least 10 μm.
It has been found that if it is m or more and 60 μm or less, sufficient cleaning ability can be obtained while preventing the occurrence of filming.

[0059]

[Table 5]

Embodiment 8 The image forming apparatus of this embodiment is different from Embodiment 1 except that dirt collecting means for collecting dirt from the conductive brush roll 6a is provided.
This is the same configuration as. As shown in FIG. 11, the dirt collecting means is a flicker bar 8 arranged so as to be located between the brush fibers of the conductive brush roll 6a.

When a black band image having a width of 1 cm was formed continuously on the image forming apparatus once every 6 seconds for 1 hour, the conductive brush roll 6a and the contact charging roll 2 were contaminated. It was confirmed that the flicker bar 8 can maintain the cleaning ability of the conductive brush roll 6a.

[0062]

In the image forming apparatus according to the first invention of the present application, not only the cleaning means is disposed in contact with the charging means, but also the cleaning means has the same DC voltage applied to the charging means. By applying a voltage having a polarity and a larger absolute value than the DC voltage applied to the charging means, a mechanical rubbing force is applied to the dirt attached to the charging means to which the DC voltage is applied. Since the electrostatic attraction force can be applied, the cleaning ability is high, and a large amount of dirt strongly adhered electrostatically to the charging means can be effectively cleaned.

In the second invention of the present application, not only the cleaning means is disposed in contact with the charging means, but also the cleaning means is formed in a brush shape, and the depth of the cleaning means biting into the charging means is further increased. Is set to 0.1 mm or more and 1.2 mm or less, so that the cleaning ability is high and the cleaning can be effectively performed before the dirt on the surface of the charging unit is deformed.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of an image forming apparatus according to a first embodiment of the invention.

FIG. 2 is a front view of a main part of the image forming apparatus of FIG.

FIG. 3 is a sealing chart of the image forming apparatus of FIG.

FIG. 4 is a modification (1) of the cleaning means of the present invention.

FIG. 5 is a modification example (2) of the cleaning means of the present invention.

FIG. 6 is a modified example (3) of the cleaning means of the present invention.

FIG. 7 is a modified example (4) of the cleaning means of the present invention.

FIG. 8 is a modified example (5) of the cleaning means of the present invention.

FIG. 9 is a relationship diagram between the cleaning voltage and the cleaning capacity in the second embodiment of the present invention.

FIG. 10 is a diagram showing the relationship between the bite depth of a conductive brush roll into a contact charging roll and the potential difference between the potential of the conductive brush roll and the potential of the contact charging roll in Example 3 of the present invention.

FIG. 11 is a front view of a main part of an image forming apparatus according to an eighth embodiment of the present invention.

[Explanation of symbols]

1: Photosensitive drum (image bearing member), 2: Contact charging roll (charging means), 6: Cleaning means.

Claims (10)

[Claims] 1. An image bearing member on which a toner image is formed, and a charging unit which is placed in contact with or close to the image bearing member and to which a DC voltage is applied. In an image forming apparatus for forming an image on a sheet, a cleaning unit is provided in contact with the charging unit, and the cleaning unit has the same polarity as the DC voltage applied to the charging unit and is applied to the charging unit. An image forming apparatus characterized in that a voltage having an absolute value larger than a direct current voltage is applied. 2. The cleaning means is a conductive brush, and the depth of penetration of the brush into the charging means is 1.4 m.
The image forming apparatus according to claim 1, wherein the image forming apparatus is m or less. 3. The absolute value difference between the voltage applied to the cleaning means and the DC voltage applied to the charging means is 200 V or more and 300.
The image forming apparatus according to claim 1, wherein the image forming apparatus has a voltage of 0 V or less. 4. The image forming apparatus according to claim 1, wherein a voltage is applied to the cleaning unit when the charging unit is not performing an image forming operation. 5. An electrophotographic method comprising: an image carrier on which a toner image is formed; and a charging unit arranged in contact with or close to the image carrier to which a voltage is applied. In an image forming apparatus for forming an image, a cleaning unit is provided in contact with a charging unit, and the cleaning unit is a brush and has a bite depth of 0.1 mm.
As described above, the image forming apparatus is 1.2 mm or less. 6. The cleaning unit and the charging unit are rotatable, and the moving speed of the surface of the cleaning unit at the position where the cleaning unit and the charging unit contact each other is V _1, and the surface of the charging unit at the contact position is set to V ₁ . When the moving speed is V ₂ ,
The image forming apparatus according to claim 5, wherein V ₁ / V ₂ is 1 or more and 2 or less. 7. The weave density of the brush used for the cleaning means is
30,000 / inch ² or more, 130,000 /
Inch ² or less, characterized in that 5 or 6
An image forming apparatus according to claim 1. 8. The image forming apparatus according to claim 5, wherein the length of each brush fiber used for the cleaning means is 2.0 mm or more and 15 mm or less. 9. The image forming apparatus according to claim 5, wherein each brush fiber used for the cleaning means has a diameter of 10 μm or more and 60 μm or less. 10. The image forming apparatus according to claim 2, further comprising a dirt collecting unit that is arranged in contact with the brush and collects dirt from the brush.