JP2003005599A - Cleaning device, process cartridge and image forming apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To surely improve cleaning performance without using a cleaning blade easily influenced by the change of operational environment and easily damaging an image carrier. SOLUTION: The cleaning roller 31 of a cleaning device 14 is arranged at an upstream position and also the cleaning brush 32 of the device 14 is arranged on a downstream position in the moving direction of a photoreceptor (image carrier) 10. The brush 32 comes into contact with the roller 31. Voltage having different polarities from each other is applied to the roller 31 and the brush 32. Thus, toner left after transfer T remaining on the photoreceptor 10 after transferring an image is mainly removed by the roller 31 and then removed by the brush 32 as an auxiliary.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image forming apparatus such as a copying machine, a printer, a facsimile, or a composite machine thereof. Of these, for example, charging, writing, development, transfer, cleaning, etc. are repeated to sequentially form toner images on the image carrier, the toner images are sequentially transferred, and the image is transferred to a transfer material such as a sheet or an intermediate transfer member. The present invention relates to an image forming apparatus to be formed. And, in such an electrophotographic recording type or electrostatic recording type image forming apparatus, the present invention relates to a process cartridge in which some of devices relating to charging, writing, developing, transferring, cleaning and the like are integrated with an image carrier. And in such an image forming apparatus,
The present invention relates to a cleaning device that removes transfer residual toner remaining on an image carrier after image transfer with a cleaning member.

[0002]

2. Description of the Related Art Conventionally, in an electrophotographic recording type image forming apparatus, generally, with rotation of an image carrier, a charging device is uniformly charged and then a laser beam is irradiated to perform writing with an exposure device. An electrostatic latent image is formed on the carrier. This latent image is visualized as a toner image by adhering toner and reversal developing it by a developing device arranged facing the image carrier.

This visible image is electrostatically transferred by a transfer device to form an image on a transfer material. The transfer material after the image transfer is placed in, for example, a heat fixing device, and by applying predetermined heat and pressure, the transfer image is fixed. On the other hand, the untransferred toner remaining on the image carrier without being transferred after the image transfer is removed by a cleaning device to prepare for the next image formation.

Since this cleaning device has a good cleaning performance, many elastic cleaning blades made of polyurethane or the like have been conventionally used as the cleaning member, and the tip thereof is pressed against the image carrier to be used.

The physical properties of the cleaning blade and the manner of contact with the image carrier greatly differ depending on the degree of adhesion of the transfer residual toner to the image carrier, the surface property of the image carrier, and the toner shape, particle size, material, etc. It also varies greatly. Therefore, it is necessary to select a blade suitable for each model and set an appropriate angle and an appropriate contact load with respect to the image carrier. In reality, the trial and error process is repeated to select and install the optimum cleaning blade.

By the way, in recent years, in the image forming apparatus using the electrophotographic method of this kind, the demand for the image quality is increasing. In order to improve the image quality, it has been found that it is effective to reduce the toner particle size and make the toner spherical. It has also been found that in a full-color image forming apparatus, the gloss of an image greatly contributes to the image quality.

In order to satisfy these requirements, there is a toner which uses a fine particle toner having a nearly spherical shape by a polymerization method or the like in consideration of good transferability. With the polymerized toner, it is possible to efficiently produce a small particle size toner having a narrow particle size distribution and a spherical toner. In particular, by using a dry spherical toner containing a modified polyester having a urea bond as at least a toner binder and containing a wax, heat-resistant storage stability, low-temperature fixing property, and hot offset resistance are excellent. When used in a full-color copying machine, an image having excellent color reproducibility, transparency, and gloss stability can be obtained.

However, it is known that the small particle diameter spherical toner produced by the polymerization method has some problems. The most important problem is that it is difficult to completely remove the transfer residual toner on the surface of the image bearing member by a cleaning unit, and defective cleaning occurs. In particular,
In the blade cleaning method, the toner is close to the closest packed state between the contact portion between the image carrier and the cleaning blade during cleaning, and the first layer toner having a strong adhesive force to the image carrier and the following two toners. The toner slips with the toner of the first layer, and the toner of the first layer remains on the image carrier due to poor cleaning.

As described above, when the transfer residual toner is strongly adhered to the image carrier, the cleaning blade easily slips through, so that it is effective to provide a cleaning brush as a cleaning auxiliary member. Usually, this cleaning brush is arranged on the upstream side of the cleaning blade in the rotation direction of the image carrier, and has the purpose of scraping off the transfer residual toner on the image carrier after transfer and facilitating the cleaning of the cleaning blade. ing.

[0010]

However, the cleaning brush has a drawback that it cannot be cleaned when the input toner becomes large. That is, since the cleaning brush is fibrous, if the amount of input toner is large, there is toner that cannot be brought into contact with the cleaning brush, and electrostatic attraction does not occur, resulting in poor cleaning. Since the toner that has passed through the cleaning brush is spherical, the blade cannot be cleaned for the above reason.

Japanese Unexamined Patent Publication (Kokai) No. 5-27651 describes that a plurality of brush rollers are provided to increase the probability of toner contact with the cleaning brush to improve the cleaning performance, but it has not been sufficient.

On the other hand, the cleaning blade has a problem that it is easily affected by changes in the operating environment, particularly changes in temperature and humidity, and damages the image carrier.

Therefore, a first object of the present invention is to reliably improve the cleaning performance without using a cleaning blade that is easily affected by changes in the operating environment and that easily damages the image carrier. .

A second object of the present invention is to reduce the number of parts, downsize the cleaning device, and reduce the cost.

Here, in the transfer device, since a high voltage is applied for discharging, positive and negative transfer residual toners are mixed on the image carrier. Further, also in the charging device, since a high voltage is applied to discharge, a discharge product is generated. In the conventional cleaning devices, the cleaning blade was strongly pressed against the image bearing member, so that the discharge product could be removed by scraping off the surface layer of the image bearing member. However, if a cleaning blade is not used, such discharge products will remain on the image carrier.

Therefore, a third object of the present invention is to make it possible to completely remove the positive and negative transfer residual toners and discharge products.

When a cleaning brush is used, the toner gradually accumulates in the cleaning brush while being scraped off and the toner is clogged, and eventually becomes a toner roll to reduce the outer diameter of the cleaning brush. was there. In such a state of the toner roll, the cleaning brush loses the effect of static elimination for weakening the adhesion of the transfer residual toner to the image carrier and the scraping performance, and thus cannot function as a cleaning assisting member.

Further, when the toner roll is in the state, the toner conveying function of the cleaning brush is lost, so that the scraped toner is accumulated between the cleaning brush and the cleaning blade, and finally, a so-called puncture is caused. However, there is a problem in that the image quality deteriorates due to poor cleaning.

In order to solve such a problem, Japanese Patent Laid-Open No. 200-200200
Japanese Patent Laid-Open No. 0-75745 discloses a technique of scraping off toner in a cleaning brush with a scraper. However, in this conventional technique, since the scraper penetrates into the cleaning brush, the durability of the cleaning brush itself is poor due to brush collapse or the like.

Another conventional example discloses a technique for sucking toner in a cleaning brush with air. However, in this conventional technique, there is a problem that the device becomes large and the noise at the time of suction is large, which causes an environmental problem.

Therefore, a fourth object of the present invention is to prevent the cleaning brush from being rolled and to improve the cleaning performance without deteriorating the durability, increasing the size of the apparatus, and increasing the noise. The object of the present invention is to surely improve the cleaning performance of the image carrier without being affected by the environmental change and damaging the image carrier.

A fifth object of the present invention is to clean the surface of the image bearing member by electrostatically removing the residual toner.

A sixth object of the present invention is to further prevent the cleaning brush from being rolled and further improve the cleaning performance.

A seventh object of the present invention is to efficiently remove the toner on the cleaning brush to further improve the cleaning performance.

An eighth object of the present invention is to provide a process cartridge which achieves the above object.

A ninth object of the present invention is to provide an image forming apparatus which achieves the above object.

[0027]

Therefore, in order to achieve the above-mentioned first object, the invention according to claim 1 removes the transfer residual toner remaining on the image carrier after the image transfer by a cleaning member. In the cleaning device of the image forming apparatus, as a cleaning member, a cleaning roller is arranged at an upstream position in the moving direction of the image carrier, and a cleaning brush is arranged at a downstream position.

According to a second aspect of the invention, in order to achieve the above-mentioned second object, the cleaning device according to the first aspect is characterized in that a cleaning brush is brought into contact with a cleaning roller.

According to a third aspect of the present invention, in order to achieve the third object described above, in the cleaning device according to the first or second aspect, voltages of different polarities are applied to the cleaning roller and the cleaning brush. It is characterized by

In order to achieve the above-mentioned fourth object, the invention according to claim 4 is a cleaning device of an image forming apparatus, wherein a transfer residual toner remaining on an image carrier after image transfer is removed by a cleaning member. A cleaning brush is provided as a cleaning member, and a cleaning roller for removing toner attached to the cleaning brush is provided, and the friction coefficient μ1 of the cleaning roller is smaller than the friction coefficient μ2 of the image carrier. .

According to a fifth aspect of the present invention, in order to achieve the fifth object described above, in the cleaning device according to the fourth aspect, the surface of the cleaning roller is coated with a conductive member, and the friction coefficient μ1 ≦ 0. 4, and a voltage is applied to the cleaning roller.

According to a sixth aspect of the present invention, in order to achieve the sixth object described above, in the cleaning device according to the fourth aspect, the surface of the cleaning roller is covered with a non-conductive member, and the friction coefficient μ1 ≦ 0. .4, and a voltage is applied to the cleaning brush.

According to a seventh aspect of the present invention, in order to achieve the seventh object described above, in the cleaning device according to the fourth, fifth and sixth aspects, a cleaning member for removing toner on the cleaning roller is provided. It is characterized by

According to an eighth aspect of the present invention, in order to achieve the above-mentioned eighth object, the process cartridge of the image forming apparatus comprises the cleaning device according to any one of the first to seventh aspects. Is characterized by.

According to a ninth aspect of the present invention, in order to achieve the ninth object, the image forming apparatus includes the cleaning device according to any one of the first to seventh aspects. To do.

[0036]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows a schematic configuration of an image forming apparatus using a cleaning device according to the present invention. The illustrated image forming apparatus is an electrophotographic recording type printer, and forms an image on a sheet S which is a transfer material according to an image signal from a computer or the like (not shown).

In the figure, reference numeral 10 is a drum-shaped photosensitive member which is an image bearing member. The photoconductor 10 is formed by coating a photosensitive material such as OPC on the outer peripheral surface of a cylindrical base body such as aluminum, and is rotated clockwise in the drawing at a peripheral speed of 200 mm / sec.

Around the photosensitive member 10, a charging device 1
1, developing device 12, transfer device 13, cleaning device 1
4 and so on. An exposure device 15 is provided on the charging device 11.
To place. Further, at the lower part of the image forming apparatus, a sheet accommodating cassette 16 is detachably provided, and a pickup roller 17 for feeding out the sheet S in the sheet accommodating cassette 16 is provided.

In the transport path 18 for transporting the sheet S fed by the pickup roller 17, the separation roller 19 and the separation roller 19 are provided on the upstream side of the transfer position a between the photoconductor 10 and the transfer device 13.
A conveyance roller 20 and a registration roller 21 are provided, and a fixing device 22 and a discharge roller 23 are provided in this order on the downstream side of the transfer position a.
Distribute.

During printing, the surface of the photoconductor 10 is uniformly charged by the charging device 11 to about -600V as the photoconductor 10 rotates. Next, in the exposure device 15,
A laser beam L controlled to be ON / OFF in accordance with image information is irradiated to perform scanning exposure, and about -200 is applied on the photoconductor 10.
An electrostatic latent image of V is formed. The electrostatic latent image formed in this manner is developed and visualized by the developing device 12 by adhering toner as a developer.

On the other hand, the pickup roller 17 is rotated at a proper timing together with the photoconductor 10 to separate the sheets S stacked therein from the sheet accommodating cassette 16.
The sheet is separated and fed one by one at 9, and is conveyed by the conveying roller 20 through the conveying path 18, and the leading end is abutted between the pair of registration rollers 21 to correct the skew, and then, on the above-described photoconductor 10. The image is sent to the transfer position a in time.

The transfer device 13 located at the transfer position a includes the transfer belt 2 between the bias roller 25 and the tension roller 26.
7 is applied to the bias roller 25, and a voltage having a polarity opposite to the charging polarity of the toner is applied to the bias roller 25 by a high voltage power source.

Then, the toner images on the photoconductor 10 are collectively transferred onto the surface of the sheet S conveyed to the transfer position a at a predetermined timing, and then sent to the fixing device 22 to apply heat and pressure to fix the transferred image. After that, the sheet is discharged by the discharge roller 23 to the outside of the image forming apparatus. The transfer residual toner remaining on the surface of the photoconductor 10 after the image transfer is removed by the cleaning device 14, the charge is removed by the charge removing device (not shown), and the next image formation starts again from the charging device 11.

By the way, in the illustrated example, as the photoconductor 10, specifically, an undercoat layer is provided on a core metal made of aluminum having an outer diameter of about 90 mm, and a thickness of 0.1 μm is provided thereon.
A so-called organic photoreceptor is used in which a charge generation layer made of a phthalocyanine compound is formed to some extent, and a charge transport layer in which a hydrazone compound is dispersed in polycarbonate as a binder having a thickness of 25 μm is further formed thereon.

FIG. 2 shows an enlarged structure of the cleaning device 14 used in the image forming apparatus of FIG.

As can be seen from FIG. 2, in the cleaning device 14, the cleaning roller 31 is disposed in the cleaning case 30 at the upstream position in the rotation direction of the photoconductor 10 as the cleaning member, and the cleaning brush 32 is disposed at the downstream position. Deploy. Then, the cleaning roller 31 is pressed against the photoconductor 10 with a force of, for example, 500 gf, and the cleaning brush 32 is provided so as to bite into it by, for example, about 1 mm. Also, the cleaning brush 32
Is also provided so as to bite into the cleaning roller 31 by about 1 mm.

The cleaning roller 31 rotates counterclockwise as opposed to the photoconductor 10 and rotates in the same direction as the photoconductor 10 at the contact position. On the other hand, the cleaning brush 32
Is, for example, 30 rpm clockwise like the photoconductor 10.
At the contact position, it rotates in the opposite direction to the photoconductor 10.

Such a cleaning brush 32 has
The bias roller 33 is provided so as to be in contact with the bias roller 33, and the cleaning blade 34 is provided so as to rotate clockwise and the tip of the bias roller 33 is brought into contact with the outer periphery of the bias roller 33. The cleaning blade 34 is supported by a blade holder 35 made of sheet metal. A recovery roller 36 is provided in the cleaning case 30.

Further, for example, the cleaning roller 31
A positive voltage is applied to the bias roller 33 by a power source 37, and a negative voltage is applied to the bias roller 33 by a power source 38. Then, voltages having different polarities are applied to the cleaning roller 31 and the cleaning brush 32.

As a result, the cleaning roller 31
The transfer residual toner T on the photoconductor 10 is mechanically scraped, and the negatively charged transfer residual toner is electrostatically removed by suction. The cleaning brush 32 scrapes off the transfer residual toner on the photoconductor 10 and electrostatically removes the positively charged transfer residual toner. At this time, discharge products (NH ₄ ⁺ etc.) on the photoconductor, which contain a large amount of positive ionic substances, are also removed by suction at the same time. Further, the cleaning brush 32 scrapes off the toner adhering to the cleaning roller 31 in a direction in which the toner does not redeposit on the photoconductor 10.

The toner attached to the cleaning brush 32 is removed by the bias roller 33. Bias roller 3
The toner adhering to 3 is scraped off by the cleaning blade 34. Then, the toner removed from the photoconductor 10, the cleaning roller 31, the cleaning brush 32, and the bias roller 33 is collected in the lower part of the case 30 and collected by the collecting roller 3.
6 is transported to the outside of the cleaning device 14 and collected in a waste toner container (not shown) without scattering, or returned to the developing device 12 for recycling.

By the way, FIG. 3 shows the structure of the above-mentioned cleaning brush 32. Specifically, as shown in FIG. 3, the cleaning brush 32 of the illustrated example has conductive and ion-adsorptive fibers 40 planted on a base cloth 41 and wound around a core metal 42 of φ8 to form a brush shape of φ16. It was done.

In the illustrated example, as the conductive fiber 40, a carbon-containing cellulose fiber having a thickness of 300D / 48 or a celluya fiber is used, and W is woven into the base fabric 41 so that the fiber density becomes 50K / inch ^2. The core metal 4 is formed into a sheet shape so as to ensure continuity with the core metal 42.
It is wound around 2 in a spiral shape.

FIG. 4 shows the cleaning performance of roller cleaning and brush cleaning.

As can be seen from the figure, it is difficult to perform 100% cleaning with roller cleaning, but a cleaning rate of 90 to 95% is obtained regardless of the residual toner input amount (transfer residual toner amount). Here, the “cleaning rate” is the weight ratio of the toner on the photoconductor 10 before and after passing through the cleaning device 14 in the rotation direction of the photoconductor 10.

On the other hand, in the brush cleaning, if the residual toner input amount is 0.1 mg / cm ² or less, 10
A cleaning performance of 0% can be obtained, but if the cleaning performance is further increased, it gradually decreases. This is because, as described above, in the brush cleaning, cleaning is performed by bringing the brush into contact with each other, and therefore, when the amount of toner increases, the brush cannot contact the brush completely.

Therefore, as in the illustrated example, the photoconductor 10
If the cleaning roller 31 is arranged at the upstream position in the moving direction of the cleaning roller, the cleaning brush 32 is arranged at the downstream position, and the cleaning roller 31 is used for the final cleaning, the cleaning performance of the photoconductor 10 is ensured. Can be improved.

Generally, a conductive material is desirable as the cleaning material. However, when the resistance is low, when a voltage is applied, a current flows through another member that comes into contact with the member, and a high electric field cannot be obtained at the position where the transfer residual toner T exists. On the other hand, when the resistance is high and the material is an insulator, a high electric field is obtained when a high voltage is applied, and the transfer force by electrostatic force increases. However, it becomes difficult to clean the roller itself.
Therefore, as a result of an experiment, the resistance value is 10 ⁵ to 10
It was found that ¹³ Ωcm is desirable.

Further, in FIG. 5, the cleaning roller 31
Alternatively, the linear velocity ratio (Vr / V), which is the ratio of the linear velocity (Vr) of the cleaning brush 32 to the linear velocity (Vo) of the photoconductor 10.
The relationship of the cleaning rate to o) is shown.

As can be seen from FIG. 5, in the roller cleaning, the cleaning rate is high when the linear velocity ratio (Vr / Vo) is 0.7 to 1.3. However, if the linear velocity ratio is higher than that, the cleaning rate decreases. This is because the toner has a spherical shape and slippage increases.

On the other hand, in brush cleaning, if the linear velocity ratio (Vr / Vo) is increased as described above, the probability of contact between the toner and the brush is increased, and the cleaning rate is improved as the linear velocity ratio is increased. However, in the case of a brush, as the linear velocity ratio is increased, the tip of the brush is split into split ends, which causes a change in brush resistance. Therefore, unnecessarily increasing the linear velocity ratio causes an adverse effect. Then, as a result of the experiment, it was found that the linear velocity ratio of 1 to 2 is suitable.

In the image forming apparatus of the illustrated example, the toner contains modified polyester having a urea bond as at least a toner binder and has a gloss of 5 to 5.
A dry spherical toner is used which has a temperature width of 50 deg or more on the surface of the fixing member in contact with a fixed image of 30%, contains wax finely dispersed therein, and has a particle size of 5 to 8 μm, which is substantially spherical.

The toner of this illustrated example is manufactured by a polymerization method, but since it has a substantially spherical shape, it has good transferability. Then, silica or the like is externally added in order to stabilize the charged performance against environmental changes.

In the illustrated example, the toner is manufactured by a polymerization method, but the method is not limited to the polymerization method, and other methods may be used. For example, a toner prepared by a conventional mechanical pulverizing and classifying method may be thermally or mechanically processed. You may make it into a round shape by subjecting it to a post-treatment. When the toner has a spherical shape, the adhesion to the image carrier is reduced and the cleaning performance can be improved.

The toner may be a one-component toner, a two-component toner or a magnetic toner.

In the example described above, cleaning of the transfer residual toner is mainly performed by the cleaning roller 31. The cleaning brush 32 is provided auxiliary. Therefore, cleaning with the cleaning brush 32 has a margin, and the brush itself is not completely covered with toner.

Therefore, it is possible to give the cleaning brush 32 another function. For example, if the brush material is made of an ion-adsorptive member, an image can be formed by adhering to the photoconductor 10 by the charging process. Disturb, causative agent NH ₄
It can also function to adsorb discharge products such as ⁺ . Examples of the ion-adsorptive material include those typified by activated carbon, Celgaia, and cellulose. Although the brush fibers may be made of these materials, the form of coating the brush may be used.

By the way, in the above-mentioned example, the photoconductor 10,
The charging device 11, the developing device 12, and the cleaning device 14 are individually provided in the image forming apparatus. However, for example, as shown in FIG.
Alternatively, the process cartridges 45 may be housed together and integrated as a process cartridge 45.

As described above, if the process cartridge 45 is integrally attached to and detachable from the image forming apparatus, the photoconductor 10, the charging device 11, the developing device 12, etc., which are difficult for the user to replace, can be individually mounted. The maintenance work can be facilitated by eliminating the trouble of replacing.

When the process cartridge system is adopted in this manner, the photoconductor 10 is selected according to the life of the process cartridge 45, and in order to maintain the surface property of the photoconductor 10 to the end of its life, the cleaning brush 32 and the cleaning brush 32 are used. It is necessary to optimize the contact conditions of the roller 31 and the like, and select the materials and design the structure so that the rollers 31 have almost the same life.

FIG. 7 shows a schematic structure of another cleaning device 14 used in the image forming apparatus as shown in FIG.

In the cleaning device 14 shown in FIG. 7, a cleaning brush 52 for removing the toner on the photoconductor 10 is provided as a cleaning member in the cleaning case 50, and the cleaning brush 5 is provided.
A cleaning roller 53 for removing the toner attached to
A cleaning blade (cleaning member) 54 for removing the toner on the cleaning roller 53 is supported by a blade holder 55. A recovery roller 56 is provided in the cleaning case 50.

As the cleaning brush 52, one having the same structure as the cleaning brush 32 of FIG. 2 described above is similarly provided. Then, the cleaning brush 52
Then, a bias voltage is applied to the cleaning roller 53.

As a result, the cleaning brush 52
The transfer residual toner T on the photoconductor 10 is mechanically scraped off, and electrostatically attracted and removed by applying a bias voltage to clean the surface of the photoconductor 10. Cleaning brush 5
The toner attached to 2 is removed by the cleaning roller 53. The toner attached to the cleaning roller 53 is scraped off by the cleaning blade 54. Then, the cleaning case 50 is removed.
The toner dropped inside is conveyed to the outside of the cleaning device 14 by the collection roller 56.

The surface static friction coefficient of the photoconductor 10 used in the illustrated example was measured and found to be 0.40.
The coefficient of static friction referred to here is measured by the Euler belt method. Paper is wound around the photoconductor 10 and a weight is attached to one end of the paper to wind the paper at a constant speed. It is calculated by.

If the cleaning operation is repeated, the cleaning brush 52 becomes clogged with the brush fibers to form a toner roll, and the cleaning performance deteriorates. This is because the toner that is not removed from the cleaning brush 52 is rubbed against the photoconductor 10 to cause the resin component to adhere to the surface of the photoconductor 10, so-called filming phenomenon, and the friction coefficient of the photoconductor 10 is increased.

FIG. 8 shows the relationship between the friction coefficient of the photoconductor 10 and the cleaning rate. As you can see from the figure,
When the friction coefficient μ2 of 0 increases, the cleaning rate decreases. In particular, the cleaning rate extremely decreases when the friction coefficient μ2 of the photoconductor 10 is around 0.4. Therefore, in the illustrated example, in order to prevent this, the cleaning roller 53 is provided to remove the toner accumulated in the brush fiber. In the illustrated example, the cleaning roller 53 is formed by coating the outermost surface of a stainless roller with a low friction coefficient member.

FIG. 9 shows the friction coefficient μ1 of the cleaning roller 53.
5 shows the relationship between the cleaning rate and the ratio μ1 / μ2 of the friction coefficient μ2 of the photoconductor 10 to the friction coefficient μ2.

As can be seen from the figure, the smaller the ratio of μ1 to μ2, the higher the cleaning performance for the cleaning brush 52 and the better the cleaning performance for the photoconductor 10. Then, when μ1 / μ2 exceeds 1, the cleaning rate starts to decrease. Therefore, it is preferable that μ1 ≦ μ2.

In FIG. 10, the surface of the cleaning roller 53 is covered with a conductive member 57 so that the friction coefficient μ1 is 0.4 or less.
An example in which a voltage is applied to the cleaning roller 53 is shown.

In this example, electroless nickel and PTFE were co-deposited in the treatment liquid to uniformly contain PTFE in the coating in an amount of 10 to 30% of the volume ratio, and heat treatment was performed after film formation to obtain electroless nickel. And PTFE are firmly adhered to each other. The film thickness is set to about 20 microns, aiming for longer life. By increasing the content of PTFE, the friction coefficient μ1 becomes smaller, and it becomes easier to remove the adhered toner from the cleaning roller 53, but there is a problem that the surface is soft and is easily scraped.

Then, in the example shown in FIG. 10, by applying the voltage V1 to the cleaning roller 53, a voltage is applied to the brush tip portion of the cleaning brush 52, and the photosensitive member 1 is electrostatically charged.
The toner above 0 adheres to the cleaning brush 52. The toner attached to the cleaning brush 52 is transferred to the surface of the cleaning roller 53 having a high electric potential.

The transferred toner is collected by the cleaning blade 54.
Is scraped off by. At this time, by setting the friction coefficient μ1 ≦ 0.4 of the surface of the cleaning roller 53 as described above,
The transferred toner is scraped off the surface of the cleaning roller 53 without slipping between the first layer and the second layer.

In the example of FIG. 10, the electro-deposition without electric field was carried out, but there is no problem even if the film is formed with an electric field. But,
When the electric field method is used, it is difficult to keep the film thickness uniform due to the concentration of the electric field strength at the end portion.

FIG. 11 shows an example in which the surface of the cleaning roller 53 is covered with a non-conductive member 58 so that the friction coefficient μ1 is 0.4 or less, and a voltage is applied to the cleaning brush 52.

In this example, the cleaning roller 53 covers the metal roller with a tube of low surface energy such as fluororesin,
It is made by a simple method that shrinks by heating and adheres closely. Then, V1 is applied to the shaft of the cleaning roller 53, and V2 is applied to the cleaning brush 52. However, V
The relation of 1 ≧ V2 is satisfied. As a result, the photoconductor 1
The toner on 0 is electrostatically attracted to the cleaning brush 52. The toner on the cleaning brush 52 is electrostatically attracted to the cleaning roller 53 having a higher electric potential, and is scraped off by the cleaning blade 54 as described above.

Incidentally, the cleaning blade 54 which is a cleaning member.
Is a polyurethane rubber adhered to the tip of the blade holder 55, which comes into contact with the photoconductor 10 under the conditions of a predetermined penetration amount d and a set angle θ as shown in FIG. In the illustrated example, as a result of finding optimum conditions by repeating trial and error, a rubber hardness of 68 ° (JIS A) is used, and θ = 20.
With the setting of ° and d = 1.5, the contact thickness to the photoconductor 10 is about 2
It is set to 0 g / cm.

Now, also in the case of the example shown in FIG.
For example, as shown in FIG. 12, a photoconductor 10 and a charging device 1
It is also possible to store the developing device 12, the developing device 12 and the cleaning device 14 in the cartridge case 44 together and integrate them into the process cartridge 45.

Similarly, the process cartridge 4
In the fifth embodiment, the image forming apparatus is detachably attached to the image forming apparatus, so that it is difficult for the user to replace the photosensitive member 1.
It is possible to eliminate the trouble of individually replacing the charging device 11, the charging device 11, the developing device 12, and the like, and facilitate maintenance.

[0090]

As described above, according to the first aspect of the invention, as the cleaning member, the cleaning roller is arranged at the upstream position in the moving direction of the image carrier, and the cleaning brush is arranged at the downstream position. After cleaning with the cleaning roller, final cleaning with a cleaning brush is possible, and the cleaning performance of the image carrier is surely improved without being significantly affected by changes in the operating environment and without damaging the image carrier. be able to.

According to the second aspect of the present invention, since the cleaning brush is brought into contact with the cleaning roller, it is possible to clean the cleaning brush with a cleaning brush having a sufficient cleaning ability, and a cleaning member for the cleaning roller is separately provided. It is possible to reduce the number of parts by eliminating the need to provide the cleaning device, downsize the cleaning device, and reduce the cost.

According to the third aspect of the invention, since voltages having polarities different from each other are applied to the cleaning roller and the cleaning brush, of the toner remaining on the image carrier after image transfer, for example, negatively charged toner is used. The cleaning roller can be electrostatically sucked and removed, and the positively charged toner can be electrostatically sucked and removed by the cleaning brush. A cleaning brush can also remove discharge products containing a large amount of positive ionic substances.

According to the invention of claim 4, a cleaning brush is provided as a cleaning member, and a cleaning roller for removing the toner adhering to the cleaning brush is provided, and the friction coefficient μ1 of the cleaning roller is the friction of the image carrier. Since the coefficient is smaller than μ2, the toner on the cleaning brush is removed by the cleaning roller, the cleaning brush is prevented from being rolled, the cleaning performance is improved, and the image bearing member is not affected by the change in the operating environment. Therefore, the cleaning performance of the image carrier can be reliably improved.

According to the fifth aspect of the present invention, the surface of the cleaning roller is covered with a conductive member so that the friction coefficient is μ1 ≦ 0.4, and a voltage is applied to the cleaning roller. Therefore, cleaning is performed via the cleaning roller. The surface of the image carrier can be cleaned by applying a voltage to the brush to electrostatically remove the residual toner.

According to the invention of claim 6, the surface of the cleaning roller is covered with a non-conductive member, and the friction coefficient μ1 ≦ 0.4.
Since the voltage is applied to the cleaning brush, the toner adhering to the cleaning brush can be surely adhered to the cleaning roller to prevent the cleaning brush from rolling and improve the cleaning performance.

According to the invention of claim 7, since the cleaning member for removing the toner on the cleaning roller is provided, the toner on the cleaning member is removed by the cleaning roller, and the toner on the cleaning brush is efficiently removed by the cleaning roller. Can be removed.

According to the invention of claim 8, since the cleaning device according to any one of claims 1 to 7 is provided, a process cartridge provided with the cleaning device having the above-mentioned effect is obtained, and the maintainability is improved. can do.

According to the ninth aspect of the present invention, since the cleaning device according to any one of the first to seventh aspects is provided, it is possible to provide the image forming apparatus including the cleaning device having the above effects. .

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram of an image forming apparatus using a cleaning device according to the present invention.

FIG. 2 is an enlarged configuration diagram of a cleaning device portion thereof.

FIG. 3 is an explanatory diagram of a configuration of a cleaning brush used in the cleaning device.

FIG. 4 is a diagram showing cleaning performance of roller cleaning and brush cleaning.

FIG. 5 is a diagram showing a change in cleaning rate with respect to a linear velocity ratio between a cleaning roller or a cleaning brush and a photoconductor.

FIG. 6 is a configuration diagram of a process cartridge in which a cleaning device is integrated with another device.

FIG. 7 is a schematic configuration diagram of another cleaning device used in the image forming apparatus as shown in FIG.

FIG. 8 is a diagram showing a relationship between a friction coefficient of the photoconductor and a cleaning rate.

FIG. 9 is a diagram showing a relationship between a cleaning rate and a ratio of a friction coefficient between a cleaning roller and a photoconductor.

FIG. 10 is a partial configuration diagram of a cleaning device using a cleaning roller covered with a conductive member.

FIG. 11 is a partial configuration diagram of a cleaning device using a cleaning roller covered with a non-conductive member.

12 is a structural explanatory view of a process cartridge in which the cleaning device shown in FIG. 7 is integrated with another device.

[Explanation of symbols]

10 Photoconductor (image carrier) 14 Cleaning device 31 Cleaning roller (cleaning member) 32 Cleaning brush (cleaning member) 37 power supply 38 power 44 cartridge case 45 process cartridge 52 cleaning brush 53 Cleaning roller 54 Cleaning blade (cleaning member) 57 Conductive member 58 Non-conductive member

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Naomi Sugimoto             1-3-3 Nakamagome, Ota-ku, Tokyo Stocks             Company Ricoh (72) Inventor Yasushi Nakazato             1-3-3 Nakamagome, Ota-ku, Tokyo Stocks             Company Ricoh F-term (reference) 2H134 GA01 GB02 HA12 HB12 HB15                       KH03 KH04 KH09

Claims (9)

[Claims] 1. A cleaning device of an image forming apparatus, wherein a cleaning member removes transfer residual toner remaining on an image bearing member after image transfer, as a cleaning member, a cleaning roller is provided at a position upstream of a moving direction of the image bearing member. And a cleaning brush at the downstream position. 2. The cleaning device according to claim 1, wherein the cleaning brush is in contact with the cleaning roller. 3. A voltage having different polarities is applied to the cleaning roller and the cleaning brush.
The cleaning device according to claim 1 or 2. 4. A cleaning device for an image forming apparatus, wherein a cleaning member removes transfer residual toner remaining on an image bearing member after image transfer, and a cleaning brush is provided as the cleaning member, and toner adhered to the cleaning brush. A cleaning device including a cleaning roller that removes the friction coefficient μ1 of the cleaning roller smaller than the friction coefficient μ2 of the image carrier. 5. The cleaning device according to claim 4, wherein the surface of the cleaning roller is covered with a conductive member so that the friction coefficient is μ1 ≦ 0.4, and a voltage is applied to the cleaning roller. 6. The cleaning device according to claim 4, wherein the surface of the cleaning roller is covered with a non-conductive member so that the friction coefficient is μ1 ≦ 0.4, and a voltage is applied to the cleaning brush. 7. The cleaning device according to claim 4, wherein a cleaning member for removing toner on the cleaning roller is provided. 8. A process cartridge of an image forming apparatus, comprising the cleaning device according to claim 1. 9. An image forming apparatus comprising the cleaning device according to claim 1.