JP2001005358A - Cleaning device for wet electrophotographic device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a cleaning device by which the wear on the surface of a photoreceptor can be decreased and whose manufacturing cost is low in a wet electrophotographic device, using a fine toner. SOLUTION: The surface of a cleaning roller 51 is electrified by a charge having the different polarity from the electrified polarity of toner, and a residual toner 103a is separated from the surface of the photoreceptor drum 1 by an electrically attracting force. At the same time, cleaning liquid is supplied to the contact surface of the drum 1 and the roller 51 from a cleaning liquid supplying path 53, so that the toner 103a can be separated easily from the surface of the drum 1.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cleaning apparatus for removing toner remaining on the surface of a photoreceptor used in a wet electrophotographic apparatus such as an electrophotographic copying machine or an electrophotographic printer.

[0002]

2. Description of the Related Art In a wet-type electrophotographic apparatus, when transferring image toner visualized on the surface of a photoreceptor to printing paper, dry toner is used as a method of removing toner remaining on the surface of the photoreceptor without being transferred to printing paper. A cleaning device using a cleaning blade and a cleaning roller, which are widely used in an electrophotographic apparatus, is generally well known.

In this cleaning blade, a ridge line having a high degree of straightness is formed on an elastic body such as urethane rubber, and this ridge line is pressed against the surface of the photoreceptor at a predetermined contact angle and a predetermined pressing force. The toner remaining on the photoreceptor surface is scraped and removed. Further, the cleaning roller collects the toner scraped by the cleaning blade, and stores and collects the toner in the cleaning device.

[0004]

However, in recent years, high resolution image quality has been demanded of electrophotographic apparatuses, so that the particle size of toner used in the electrophotographic process tends to be finer. In particular, in a wet electrophotographic apparatus, the toner is dispersed in a highly insulating solvent and used, so that a fine toner can be easily used. At present, a toner having a toner particle diameter of 1 to 2 μm has been put to practical use.

However, when the toner is miniaturized, a new problem occurs in the conventional cleaning device. For example, in order to completely remove fine toner adhering to the surface of the photoconductor, the pressing force of the cleaning blade in contact with the surface of the photoconductor must be increased as compared with the conventional case. Is promoted, and the life of the photoconductor is shortened.

Further, unless the straightness of the ridgeline at which the cleaning blade contacts the photoreceptor is reduced to about 10 μm or less, good cleaning performance cannot be obtained, so that more precise processing is required. At the same time, it is necessary to more strictly control the properties of the cleaning blade, such as the material and the rebound resilience, and to suppress the quality of the cleaning blade within a certain limited range.

Furthermore, the range of assembly adjustment, such as the angle at which the cleaning blade is brought into contact with the surface of the photoreceptor, the free length of the cleaning blade, and the pressing force of the cleaning blade is limited to a narrower range. Requires more advanced assembly and adjustment work, and the cost of the entire apparatus is high.

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a cleaning device which reduces the wear applied to the surface of the photoreceptor by the cleaning device to prolong the life of the photoreceptor, and which can be easily assembled and adjusted at a low cost.

[0009]

In order to solve the above-mentioned problem, the present invention is directed to a cleaning apparatus for removing residual toner on the surface of a photoreceptor used in a wet electrophotographic apparatus utilizing a reversal development process. And a rotatable cleaning roller disposed in contact with or slightly spaced from the photoreceptor surface, and liquid supply means for supplying an insulating liquid to an outer peripheral surface of the cleaning roller. In a state where the insulating liquid is supplied from the liquid supply means, the outer peripheral surface of the cleaning roller has a potential different from the polarity of the charged polarity of the toner in the developer.

The invention according to claim 2 is the cleaning device according to claim 1, wherein the insulating liquid supplied from the liquid supply means is a carrier.

According to a third aspect of the present invention, there is provided the cleaning device according to the first or second aspect, wherein a squeeze means for contacting the surface of the photosensitive member is provided downstream of the cleaning roller in the moving direction of the photosensitive member. It is characterized by the following.

According to a fourth aspect of the present invention, there is provided the cleaning apparatus according to any one of the first to third aspects, wherein the residual toner on the surface of the photoreceptor has the same polarity as the charge polarity of the toner in the developer. And a charging unit for providing the electric charge of the photoconductor is provided upstream of the cleaning roller in the moving direction of the photoconductor.

According to a fifth aspect of the present invention, there is provided the cleaning apparatus according to any one of the first to fourth aspects, further comprising an electrode disposed at a small gap from an outer peripheral surface of the cleaning roller. In the step, in a state where the insulating liquid is filled between the electrode and the outer peripheral surface of the cleaning roller, the electrode has the same polarity and an absolute value as compared with a potential applied to the outer peripheral surface of the cleaning roller. Has a high potential.

According to a sixth aspect of the present invention, there is provided the cleaning apparatus according to any one of the first to fourth aspects, wherein the cleaning device is provided at any time when the cleaning step is not performed.
The outer peripheral surface of the cleaning roller has a potential or an alternating potential that is the same as the polarity of the charged toner in the developer.

According to a seventh aspect of the present invention, in the cleaning device according to the fifth aspect, the outer peripheral surface of the cleaning roller and the electrode are immersed in the developing solution at any time when the cleaning step is not performed. And has an electric potential or an alternating electric potential which is the same as the charging polarity of the toner.

[0016]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a schematic configuration diagram of a wet electrophotographic apparatus to which the present invention is applied. In this wet electrophotographic apparatus, a toner having a toner particle diameter of 1-2 in a highly insulating solvent (hereinafter, referred to as a carrier) as a developer (hereinafter, referred to as a developer).
The photosensitive drum 1, the charging unit 2, the exposing unit 3, the developing unit 4, the transfer unit 6,
A fixing unit 8, a pre-cleaning exposure unit 9, a pre-cleaning charging unit 10, a cleaning unit 11, and a charge removing unit 13 are provided.

The photoreceptor drum 1 has a photoconductive layer formed on the outer periphery thereof. The charging section 2 uniformly positively charges the outer peripheral surface of the photosensitive drum 1 in a dark place by a corona discharger. The exposure unit 3 irradiates light to an area to be visualized according to image data supplied from an image data supply unit (not shown) to eliminate the positive charges in that area.
On the other hand, since light is not irradiated to a region which is not visualized, a positive charge remains. Thus, an electrostatic latent image is formed on the outer peripheral surface of the photosensitive drum 1 due to the difference in charged potential.

The developing unit 4 has a developing roller 5 whose lower part is immersed in a developing solution. The developing solution adheres to the outer circumferential surface of the developing roller 5 by rotation of the developing roller 5, and the developing solution is applied to the outer circumferential surface of the photosensitive drum 1. Supply. The toner in the developer has a positive charge.

The toner supplied to the outer peripheral surface of the photosensitive drum 1 adheres to a visualized area having a relatively low positive potential in the electrostatic latent image due to an electric attraction force. Are visualized as toner images. This is called a reversal development process.

The transfer section 6 transfers the toner image formed on the outer peripheral surface of the photosensitive drum 1 to the printing paper P conveyed from a printing paper supply section (not shown) to the transfer drum 7 (hereinafter, referred to as a transfer step). ). The fixing unit 8 heats the toner image transferred to the printing paper P.

The pre-cleaning exposure unit 9 is an exposure device that irradiates the entire outer peripheral surface of the photosensitive drum 1 with uniform light. The pre-cleaning charging unit 10 charges the toner remaining on the outer peripheral surface of the photosensitive drum 1 with electric charge. Is a corona discharger. The cleaning unit 10 collects toner remaining on the outer peripheral surface of the photosensitive drum 1 (hereinafter, referred to as a cleaning step). The charge removing section 13 is an AC corona discharger, and removes positive charges remaining on the outer peripheral surface of the photosensitive drum 1 by corona ions.

When the photosensitive drum 1 rotates at a constant speed in the direction of arrow A, the charging unit 2, the exposing unit 3, the developing unit 4, the transfer unit 6, the pre-cleaning exposing unit 9, the pre-cleaning charging unit 10, the cleaning unit 11 and the process of the charge removing unit 13 are continuously performed, and a predetermined toner image is formed on the printing paper P. Thereafter, the toner image on the printing paper P is heated by the fixing unit 8 and is permanently fixed on the printing paper P.

Next, based on FIG. 2, the pre-cleaning exposure section 9 and the pre-cleaning charging section 1 according to the embodiment of the present invention will be described.
0 and the cleaning unit 11 will be described in detail. FIG. 2 is a cross-sectional view illustrating a schematic configuration of the pre-cleaning exposure unit 9, the pre-cleaning charging unit 10, and the cleaning unit 11.

The pre-cleaning exposure unit 9 irradiates light onto the entire outer peripheral surface of the photosensitive drum 1 after the transfer process,
Of the positive charges charged on the outer peripheral surface of the photoreceptor drum 1 in the charging unit 2, the exposure unit 3
Erases the positive charges remaining in the region where the light was not irradiated.

The pre-cleaning charging section 10 has the same polarity as the charge polarity of the toner in the developer with respect to the toner remaining on the outer peripheral surface of the photoreceptor drum 1 (hereinafter referred to as residual toner) without being transferred to the printing paper in the transfer step. A positive charge (hereinafter, referred to as the same polarity as the toner) is applied by a corona discharger and forcedly charged. This is because, among the residual toner, the residual toner that has adhered particularly to the invisible image area has a relatively small charge amount and weak electric attraction in the cleaning process. Efficiency is reduced. In order to improve the collection efficiency by forcibly charging the residual toner with a positive charge, this is provided.

In the embodiment of the present invention, a corona discharger is used as the charging means. However, a roller charger or a brush charger may be used as long as it provides a charge to the residual toner. However, a charger that contacts the residual toner and gives an electric charge, because the residual toner adheres to the charger itself and becomes contaminated, is preferably a non-contact charger.

The pre-cleaning charging section 10 also applies a positive charge to the outer peripheral surface of the photoreceptor 1 to charge it.
The positive charge charged on the outer peripheral surface of the photoconductor 1
3 so that it does not adversely affect the electrophotographic process.

The cleaning unit 11 includes a cleaning roller 51, a squeeze roller 52, and a cleaning liquid supply path 5.
3, an electrode 54, a scraper 55, a discharge path 56, and a cleaning case 57.

The cleaning roller 51 is a roller having sufficient cleaning performance and having a material, hardness, and structure that minimizes adverse effects such as abrasion on the surface of the photoreceptor 1. Has characteristic characteristics.
For example, a conductive rubber layer having an electric resistance of about 10 ^{4 to 8} Ω · cm is formed on the outer periphery of a metal shaft core, and the outer periphery thereof is further coated with an insulating protective layer. There is an outer periphery coated with an elastic body, a conductive thin film, and an insulating protective layer in this order, but in the embodiment of the present invention, the outer periphery of the conductive rubber layer having the former form is provided with an insulating protective layer. A fluorine-based coating is applied as a layer.

In the cleaning step, the cleaning roller 51 is supplied with a voltage which is a negative polarity of a polarity opposite to the charge polarity of the toner in the developer (hereinafter referred to as a toner and a different polarity) and whose potential is variable. Further, at any time other than the cleaning step, it is possible to apply a voltage whose potential is variable with a positive pole having the same polarity as that of the toner or an alternating voltage whose polarity is periodically changed and whose potential is variable. By changing the applied voltage and polarity, the outer peripheral surface of the cleaning roller 51 is controlled to an arbitrary potential and polarity.

Since the cleaning roller 51 is provided so as to be in contact with the outer peripheral surface of the photosensitive drum 1, it does not have its own driving means, but the rotation of the photosensitive drum 1 is caused by the contact resistance with the photosensitive drum 1. Rotates dependently. In the embodiment of the present invention, the cleaning roller 51 is used.
Is provided in contact with the outer peripheral surface of the photosensitive drum 1, but may be provided in a non-contact manner with a slight gap. In this case,
Since a sufficient cleaning liquid can be supplied to the surface of the photosensitive drum 1 and the opposite portion of the cleaning roller 51 by a cleaning liquid supply path 53 described later, the toner adhering to the surface of the photosensitive drum 1 is electrophoretically transferred to the roller. It can be moved. However, since there is no contact resistance, a unique means for rotationally driving the cleaning roller 51 is required.

The squeeze roller 52 is formed by covering an iron core with urethane foam, and is provided so as to be in contact with the outer peripheral surface of the photosensitive drum 1. The squeeze roller 52 does not have its own driving means. The rotation of the photosensitive drum 1 depends on the contact resistance with the rotation of the photosensitive drum 1. In addition, after being provided so as to be in contact with the outer peripheral surface of the photosensitive drum 1, the photosensitive drum 1 may be rotationally driven in an arbitrary direction by a unique rotational driving unit.
The squeeze roller 52 collects the carrier that is not removed by the cleaning roller 51 and the residual toner slightly remaining on the outer peripheral surface of the photosensitive drum 1 while squeezing.

In the embodiment of the present invention, a squeeze roller is used as the squeeze means. However, a cleaning blade may be used in contact with the surface of the photoreceptor.
In this case, the pressing force of the cleaning blade in contact with the photoreceptor surface is sufficient to be equal to or less than the pressing force of the conventional cleaning device, and does not need to be increased. In addition, the range of assembly adjustment when the cleaning blade is brought into contact with the surface of the photoconductor can be widened.

The cleaning liquid supply path 53 supplies the cleaning liquid from the cleaning liquid tank (not shown) to the outer peripheral surface over the entire length of the cleaning roller 51 in the axial center direction. The cleaning liquid is applied to the cleaning roller 5 to which a voltage has been applied in the cleaning process.
An insulating liquid is used so as not to weaken the electric attraction between the toner 1 and the toner, and is always supplied during the cleaning process. By the way, the carrier is an insulating liquid designed to efficiently charge the toner in the developing solution. Therefore, in the embodiment of the present invention, the carrier is used as a cleaning liquid. As a result, the collected toner and carrier can be reused by removing impurities and supplying them to the developer.

The electrode 54 is a thin plate conductor having a length equal to or longer than the entire length of the cleaning roller 51 in the axial direction.
The cleaning roller 51 is provided in parallel with the axial direction and with a slight gap from the outer peripheral surface. This electrode 54
In the cleaning process, a voltage that is a negative pole different from the toner and that is higher in absolute value than the outer peripheral surface potential of the cleaning roller 51 is applied. On the other hand, at an arbitrary time other than the cleaning step, it is possible to apply a voltage whose potential is variable at the positive pole of the same polarity as that of the toner or an alternating voltage whose polarity is changed periodically and the potential is variable. By changing the applied voltage and polarity, the electrode 5
4 is controlled to an arbitrary potential and polarity.

The scraper 55 is provided in contact with the outer peripheral surface of the cleaning roller 51, and scrapes the toner and the carrier collected on the outer peripheral surface of the cleaning roller 51 to the bottom of the cleaning case 57.

The discharge path 56 is provided between the bottom of the cleaning case 57 and a collection tank (not shown), and the toner and the carrier scraped to the bottom of the cleaning case 57 pass through the discharge path 56 to the collection tank. Is discharged.

Next, the operation up to the cleaning step after the transfer step will be described in detail with reference to FIG. A conductive rubber layer 100 and an insulating layer 101, which is a fluorine-based coating, are provided on the outer periphery of the cleaning roller 51.

After the transfer step, the positive charges remaining on the outer peripheral surface of the photosensitive drum 1 are removed by the pre-cleaning exposure unit 9 as described above, and the residual toner 103a remaining on the outer peripheral surface of the photosensitive drum 1 is cleaned. A positive charge having the same polarity as that of the toner is given by the corona discharger by the pre-charging unit 10 and is forcibly charged.

Residual toner 103a forcibly charged
Is transported to the contact surface of the cleaning roller 51 with the insulating layer 101 as the photosensitive drum 1 rotates in the direction of arrow A. At this time, since a negative voltage is applied to the conductive rubber layer 100 of the cleaning roller 51, the insulating layer 101 is charged with a negative charge having a different polarity from that of the toner, and the residual toner 103a is electrically attracted. The surface of the insulating layer 101 is sucked and moved.

In addition, the photosensitive drum 1 and the insulating layer 101
Since the carrier, which is a cleaning liquid, is supplied from the cleaning liquid supply path 53 to the contact surface of, the toner can easily move to the surface of the insulating layer 101.

The toner 10 adhered to the surface of the insulating layer 101
3b is conveyed to the surface facing the electrode 54 as the cleaning roller 51 rotates in the direction of arrow B.
Since there is only a slight gap between the surface of the insulating layer 101 and the electrode 54, the opposing space is filled with the carrier supplied from the cleaning liquid supply path 53.

Since a negative voltage, which has a different polarity from the toner and is higher in absolute value than the voltage applied to the conductive rubber layer 100, is applied to the electrode 54, the insulating layer 10
The toner 103b adhering to the surface of the carrier 1 moves in the carrier to the side of the electrode 54 where electric attraction is superior. However, since the carrier is continuously supplied between the surface of the insulating layer 101 and the electrode 54, the toner 103 c that has attempted to move to the electrode 54 side is caused to flow by the carrier and falls on the surface of the insulating layer 101. .

Thereafter, the toner 103c is
5, is scraped off from the surface of the insulating layer 101, falls to the bottom of the cleaning case 57 shown in FIG.
Through the collection tank.

As described above, most of the residual toner 103a attached to the surface of the photosensitive drum 1 is removed. Then, the residual toner 103e still slightly remaining on the surface of the photosensitive drum 1, the developing solution, and the carrier supplied from the cleaning liquid supply path 53 are scraped off by the squeeze roller 52 shown in FIG. Removed from the surface. The residual toner 103e can be easily separated from the photosensitive drum 1 with a small force because the adhesive force of the residual toner 103e with the photosensitive drum 1 is weakened by the cleaning roller 51. Thus, the squeeze roller 52
Is a supplement to the last, so that the mechanical load on the surface of the photosensitive drum 1 can be greatly reduced as compared with a conventional cleaning blade.

The toner 103b adhered to the surface of the insulating layer 101 is removed from the surface of the insulating layer 101 by the electrode 54 and the scraper 55. As the cleaning process proceeds, the toner remaining on the surface of the insulating layer 101 is removed. This may hinder the cleaning process.
Further, the amount of the toner 103d attached to the surface of the electrode 54 also increases as the cleaning process proceeds.

Therefore, referring to FIG.
The operation of cleaning the surfaces of the electrode and the electrode 54 will be described.
At any time during the period when the cleaning device is not performing the cleaning step which is a part of the electrophotographic process, a positive voltage having the same polarity as that of the toner is applied to the conductive rubber layer 100 and the electrode 54. At the same time, carriers are continuously supplied to the surface of the insulating layer 101 from the cleaning liquid supply path 53,
The space between the surface of the insulating layer 101 and the electrode 54 is filled with carriers.

As a result, the toner 103b is
The toner 103 d receives an electric repulsion from the surface of the electrode 54 and receives an electric repulsion from the surface of the electrode 54 to separate from the surface of the electrode 54. Since the surface is continuously supplied in a state of being filled with the carrier, the toner 103b and the toner 103d separated into the carrier are flown by the carrier and fall on the surface of the insulating layer 101.

Thereafter, the toner 103b and the toner 103d
Is scraped off from the surface of the insulating layer 101 by the scraper 55, falls to the bottom of the cleaning case 57 shown in FIG.
Thus, the surfaces of the insulating layer 101 and the electrode 54 can always be kept clean.

In the operation of cleaning the surfaces of the insulating layer 101 and the electrode 54 in the embodiment of the present invention, a positive voltage having the same polarity as that of the toner was applied to the conductive rubber layer 100 and the electrode 54. The same effect can be obtained by applying an AC voltage whose polarity alternates with a constant period as shown in FIG.

[0051]

As described above, according to the cleaning apparatus of the first aspect, the rotatable cleaning roller disposed in contact with or slightly spaced from the surface of the photosensitive member, and the insulating liquid is applied to the outer peripheral surface of the cleaning roller. Liquid supply means for supplying, and in the cleaning step, the outer peripheral surface of the cleaning roller has a potential of a different polarity from the charged polarity of the toner in the developing solution, so that the cleaning device wears the photoreceptor surface. And the life of the photoconductor can be prolonged.

Further, according to the cleaning device of the present invention, since the insulating liquid supplied from the liquid supply means is a carrier for the developer, the charge amount of the toner can be maintained at a high level and the efficiency can be improved. The residual toner can be collected.

According to the third aspect of the present invention, the squeezing means for contacting the surface of the photoreceptor is provided downstream of the cleaning roller in the moving direction of the photoreceptor. The liquid and the insulating liquid supplied from the liquid supply means can be recovered.

According to the cleaning device of the present invention, the charging means for giving the same polarity of charge to the toner on the surface of the photoreceptor as the charge polarity of the toner in the developing solution is provided upstream of the cleaning roller in the moving direction of the photoreceptor. With this arrangement, the electric suction force is increased, and the residual toner can be efficiently collected.

According to the fifth aspect of the present invention, there is provided the cleaning device, wherein the electrode is disposed with a small gap from the outer peripheral surface of the cleaning roller, and the insulating liquid is provided between the electrode and the outer peripheral surface of the cleaning roller in the cleaning step. When the electrode is full, the electrode has the same polarity as the voltage applied to the outer peripheral surface of the cleaning roller and has a higher potential in absolute value, so that toner is less likely to adhere to the outer peripheral surface of the cleaning roller and is always cleaned. Condition can be maintained.

According to the cleaning device of the sixth aspect, at any time when the cleaning step is not performed,
Since the outer peripheral surface of the cleaning roller has the same polarity or alternating potential as the charge polarity of the toner in the developer, the outer peripheral surface of the cleaning roller should be subjected to the cleaning process in a state where toner is unlikely to adhere and is always clean. Can be.

According to the cleaning device of the seventh aspect, at any time when the cleaning step is not performed,
Since the outer peripheral surface of the cleaning roller and the electrode have the same polarity or an alternating potential as the charge polarity of the toner in the developer, the outer peripheral surface of the cleaning roller and the electrode are always in a clean state where the toner does not easily adhere. It can be subjected to a cleaning step.

[Brief description of the drawings]

FIG. 1 is a side view showing a schematic structure of an electrophotographic apparatus according to an embodiment of the present invention.

FIG. 2 is a sectional view showing a schematic configuration of a cleaning unit 11;

FIG. 3 is an explanatory diagram showing an operation state of a cleaning roller 51.

FIG. 4 is an explanatory diagram showing an operation state of a cleaning roller 51.

FIG. 5 is an explanatory diagram showing an operation state of a cleaning roller 51.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 photoconductor drum 2 charging unit 3 exposure unit 4 development unit 6 transfer unit 8 fixing unit 9 exposure unit before cleaning 10 charging unit before cleaning 11 cleaning unit 13 static elimination unit 51 cleaning roller 52 squeeze roller 53 cleaning liquid supply path 54 electrode 55 scraper 56 Discharge path 57 Cleaning case 100 Conductive rubber layer 101 Insulating layer 103a Residual toner 103b, 103c, 103d, 103e Toner

Claims (7)

[Claims] 1. A cleaning device for removing residual toner on the surface of a photoreceptor used in a wet electrophotographic apparatus using a reversal development process, wherein the cleaning device is rotatable disposed in contact with the photoreceptor surface or with a small gap therebetween. A cleaning roller; and a liquid supply unit for supplying an insulating liquid to an outer peripheral surface of the cleaning roller. In the cleaning step, the outer peripheral surface of the cleaning roller is supplied with the insulating liquid from the liquid supply unit. A cleaning device having a potential different from that of a charged polarity of a toner in a developer. 2. The cleaning device according to claim 1, wherein the insulating liquid supplied from the liquid supply means is a carrier. 3. The cleaning device according to claim 1, further comprising a squeezing unit that comes into contact with the surface of the photoconductor downstream of the cleaning roller in the moving direction of the photoconductor. . 4. A cleaning device according to claim 1, wherein the charging means for applying a charge having the same polarity as the charge polarity of the toner in the developing solution to the residual toner on the surface of the photoreceptor is provided. A cleaning device provided upstream of the cleaning roller in the moving direction of the photoconductor. 5. The cleaning device according to claim 1, further comprising an electrode disposed with a slight gap from an outer peripheral surface of the cleaning roller, wherein the electrode and the electrode are disposed in a cleaning step. In a state where the insulating liquid is filled between the electrode and the outer peripheral surface of the cleaning roller, the electrode has the same polarity and a higher potential in absolute value than the electric potential applied to the outer peripheral surface of the cleaning roller. A cleaning device characterized by the following. 6. The cleaning device according to claim 1, wherein an outer peripheral surface of the cleaning roller is provided with toner in a developer at an arbitrary time when a cleaning process is not performed. A cleaning device having the same polarity or alternating potential as the charging polarity. 7. The cleaning device according to claim 5, wherein at any time during which the cleaning step is not performed, the outer peripheral surface of the cleaning roller and the electrode are charged with the polarity of toner charge in a developer. A cleaning device having the same polarity or alternating potential.