JPH06130875A - Cleaner for image forming device - Google Patents

Abstract

PURPOSE:To provide an image forming device cleaner capable of satisfactorily clearing up residual toner having a variation in an amount of electrification by using two cleaning brushes to which bias voltages of the same polarity are impresud, and making the cleaning brushes different from each other in bias voltage intensity. CONSTITUTION:The cleaning brushes 11 and 12 are provided in contact with a photosensitive body 1. A bias voltage with the polarity opposite that of toner T is impressed to the cleaning brush 11 via a resistor 18 and a toner recovering roller 21. A bias voltage of the same polarity, higher than the above one, is impressed to the cleaning brush 12 via a recovering roller 22.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cleaning device for an image forming apparatus, and more particularly to a cleaning device using a cleaning brush.

[0002]

2. Description of the Related Art In an image forming apparatus such as a copying machine, a facsimile, a printer, etc., which uses an image carrier made of, for example, a photoconductor, after transferring a toner image formed on the image carrier to a recording medium, The toner remaining on the surface of the image carrier is cleaned and removed by various types of cleaning devices. In such a cleaning device using a cleaning brush, a bias voltage having a polarity opposite to that of the toner to be cleaned is applied to the cleaning device,
While the toner on the surface of the image carrier is electrostatically attracted to the cleaning brush side, the toner on the surface of the image carrier is scraped off by the brush.

With such a cleaning brush,
When the residual toner on the surface of the image carrier is removed, if the charged state of the toner changes, cleaning failure may occur.

FIG. 5 shows the structure of an experimental machine used to understand how the charged state of the toner to be cleaned changes due to the action of charging and discharging.

In this experimental machine, as an example of the image carrier,
A drum-shaped photosensitive member 101 is used, which is uniformly charged by a negative DC corona discharge by the charging charger 102. After the surface of the photoconductor is uniformly charged by such a charger 102, the developing device 103 applies toner to the surface of the photoconductor. Reference numeral T indicates a negative polarity toner attached to the surface of the photoconductor by the application. Developing device 103
An electric field that causes the toner on the developing roller 103a to migrate to the surface of the photoconductor 101 is applied between the developing roller 103a and the photoconductor 101, and the negatively charged toner T
Is attached to the surface of the photoconductor 101.

The toner thus attached to the photosensitive member 101 is the toner after development, and the distribution of the charge amount of the toner after development is as shown in FIG. 6A.
The broken line in FIG. 6 indicates the peak. Returning to FIG. 5, after the development, the toner T on the surface of the photoconductor is subjected to positive DC corona discharge by the charge eliminating charger 104, and its polarity is inverted to the positive polarity. The purpose of the experiment using this experimental machine is to grasp how the charge amount distribution changes by the corona discharge of the positive and negative polarities of the toner, which is called the static eliminator charger 104. Is a charger that serves its purpose.

When the toner after development is subjected to a positive corona discharge by the charge removing charger 104, its charge amount distribution (charge amount distribution after charge removal) becomes as shown in FIG. 6B. Next, when the toner on the surface of the photoconductor is again subjected to the negative corona discharge by the charging charger 102, the charge amount distribution becomes as shown in FIG. Further, when the positive charge corona discharge is again received by the static eliminator charger 104, its charge amount distribution (charge amount distribution after re-static charge elimination) becomes
As shown in FIG. 8, B '.

In any case, when the toner T on the photosensitive member 101 is repeatedly subjected to corona discharge of both positive and negative polarities, the frequency distribution of the toner charge amount changes from a dense shape to a sparse shape, that is, From a sharp shape to a broad shape with a wide skirt.

When the toner charge amount distribution has such a broad shape, cleaning cannot be performed even if the cleaning brush of the cleaning device is brought into contact with the surface of the photosensitive member and a predetermined bias voltage is applied to the brush. Toner is generated and cleaning failure occurs.

Even in an actual image forming apparatus, since the charge polarity of the toner adhered on the image carrier is often changed, the toner remaining on the image carrier is cleaned after the toner image is transferred to the recording medium. When doing, cleaning failure occurs.

In this type of image forming apparatus, an image bearing member made of, for example, a photoconductor is charged to a predetermined polarity, then imagewise exposed to form an electrostatic latent image, and the latent image is charged to a predetermined polarity. The toner image is converted into a toner image by the formed toner.When the toner image is transferred to the transfer medium or the recording medium is separated from the photoconductor, or when the charge polarity of the residual toner is aligned before cleaning the photoconductor, the toner is Is subjected to a charging action having the same or opposite polarity as its original charging polarity, the toner charge amount distribution when cleaning the photosensitive member with the cleaning brush of the cleaning device is in a broad state. For this reason, there is an unavoidable possibility of defective cleaning of residual toner after the toner image transfer step, and usually defective cleaning of toner having a particularly large charge amount or toner having a particularly small charge amount occurs. When such cleaning failure occurs, background stains on the image occur and the image quality deteriorates.

In JP-A-60-170879, there are 2
Although it has been proposed to use a book cleaning brush and apply a positive and negative polarity bias voltage to each of the brushes, it is difficult to solve the above-mentioned problems with such a configuration.

[0013]

An object of the present invention is to use at least two cleaning brushes to which a bias voltage of the same polarity is applied and to change the magnitude of the bias voltage between the two cleaning brushes. Provided is a cleaning device for an image forming apparatus, which makes it possible to uniformly and satisfactorily clean toner whose charge amount varies within a range of a predetermined polarity, thereby preventing defective toner removal. is there.

Another object of the present invention is also to use at least two cleaning brushes to which a bias voltage of the same polarity is applied and to change the magnitude of the bias voltage between the two cleaning brushes. To provide a cleaning device for an image forming apparatus, which is capable of uniformly and satisfactorily cleaning toner having a variable charge amount within a range of a predetermined polarity so as to prevent defective toner removal. .

[0015]

In order to achieve the above object, the present invention rubs against the surface of an image carrier to electrostatically remove the toner remaining on the surface of the image carrier after the toner image transfer step. A first cleaning brush that removes the toner while sucking it in, and is provided on the downstream side in the moving direction of the image carrier with respect to the first cleaning brush, and similarly rubs on the surface of the image carrier. And a second cleaning brush that electrostatically attracts and removes the residual toner, and a toner that has a bias voltage of the same polarity with respect to the first and second cleaning brushes and should be removed. Bias voltage applying means for applying a bias voltage of opposite polarity, wherein the bias voltage applying means applies a bias voltage of a magnitude different from the bias voltage applied to the first cleaning brush. It proposes a configuration in which a means for applying the second cleaning brush.

At this time, it is effective that the bias voltage applying means is a means for applying a bias voltage larger than the bias voltage applied to the first cleaning brush to the second cleaning brush.

Another object of the present invention is to achieve the above object by rubbing the surface of the image bearing member to electrostatically attract and remove the toner remaining on the surface of the image bearing member after the transfer step. And a first cleaning brush that is provided on the downstream side of the first cleaning brush in the moving direction of the image carrier, and similarly slides on the surface of the image carrier to remove the residual toner electrostatically. A second cleaning brush that removes by scraping while electrically attracting, a first toner collecting roller that is in contact with the first cleaning brush, and that electrostatically attracts and collects toner adhering to the cleaning brush; The second toner collecting roller, which is in contact with the second cleaning brush and electrostatically attracts and collects the toner attached to the cleaning brush, and the first and second toner collecting rollers have the same polarity. Bias voltage applying means for applying a bias voltage having a polarity opposite to that of the toner to be removed, the bias voltage applying means of which bias voltage is applied to the first toner collecting roller. It proposes a configuration which is a means for applying a bias voltage larger than the voltage to the second toner collecting roller.

At this time, the bias voltage applying means includes a bias voltage power supply, a first connection circuit for electrically connecting the bias voltage power supply and the first toner collecting roller through a resistor, and the bias voltage. It has a second connection circuit for electrically and directly connecting the power supply and the second toner collecting roller, and is configured by connecting the first and second connection circuits in parallel. And is effective.

[0019]

Embodiments of the present invention will now be described in detail with reference to the drawings.

FIG. 1 is a schematic configuration diagram of a cleaning device according to an embodiment of the present invention.

The cleaning device 10, which is also called an electrostatic brush cleaning device, is provided so as to face the photoconductor 1 which is an endless belt. Photoconductor 1 is roller 1
It is stretched between 3, 14 and other rollers (not shown), and is rotationally driven in the direction of arrow a. The belt photosensitive member 1 constitutes one example of the structure of the image bearing member, and a drum-shaped photosensitive member can also be used.

As described above, the photosensitive member 1 is uniformly charged with a predetermined polarity, in this example, negative polarity, by a charging charger (not shown), and this charged surface is subjected to image exposure. Electrostatic latent image is formed. When this latent image passes through a developing device (not shown), it is visualized as a toner image by toner charged to a predetermined polarity, in this example, positive polarity. Then, the toner image is transferred to a recording medium (not shown) made of, for example, transfer paper under the action of the transfer electric field, and the transfer paper is separated from the photoconductor 1 under the action of the separation electric field. After such a toner image transfer process, the photoconductor 1
The toner remaining on the top is removed by the cleaning device 10 shown in FIG.

In FIG. 1, the housing members 2, 3, 4
Constitutes an outer portion of the cleaning device 10, and two cleaning brushes 11 and 12 are provided inside the outer portion so as to be adjacent to each other. One of the cleaning brushes 12 is provided downstream of the other cleaning brush 11 in the moving direction of the photoconductor 1. From such a point, the cleaning brush 11 is referred to as the first
Cleaning brush, called cleaning brush 12
Will be referred to as a second cleaning brush.

Both of the cleaning brushes 11 and 12 are rotationally driven in the directions of the arrows so as to rub against the surface of the photoconductor 1. Both cleaning brushes 11,1
At the time of such rotation, 2 electrostatically attracts the toner remaining on the surface of the photoconductor 1 after the toner image transfer step, and scrapes it off.

First and second cleaning brushes 11,
A first toner collecting roller 21 and a second toner collecting roller 22 are in contact with the brush 12 so as to bite into the respective brushes, and the scraper members 5, 6 are attached to the respective toner collecting rollers 21, 22. But they are in contact with each other. On the back side of the photoreceptor 1, the first and second cleaning brushes 1
Backup rollers 7 and 8 so as to face 1 and 12
Are each pressure contact deployed. A cleaning lamp 9 is provided on the back side of the photoconductor 1, and the functions of these elements will be described later.

First and second cleaning brushes 11,
The reference numeral 12 is composed of a cored bar made of, for example, aluminum on which a large number of fibers such as a fur brush are planted, and the fibers and the cored bar are integrally driven to rotate. The fibers of the cleaning brushes 11 and 12 have a volume resistivity of 10 ^{2 to} 10 ⁸ Ωcm, preferably 10 ^{5 to} 10 ⁶ Ωcm.

A pre-cleaning charge eliminator 15 is provided on the upstream side of the first cleaning brush 11 so as to face the photoconductor 1. The pre-cleaning charge eliminator 15 is connected to a positive DC bias voltage power supply 16. Then, a high voltage having a positive polarity is applied to the charger 15 to generate a positive corona discharge.

On the other hand, for the purpose of forming a cleaning electric field, the first toner collecting roller 21 is connected to the negative DC bias voltage power source 17 via the resistor 18, and the second toner collecting roller 22 is DC. Bias voltage power supply 17
Is directly connected to. That is, the first connection circuit shown by reference numeral 19 electrically connects the DC bias voltage power supply 17 and the first toner collecting roller 21 via the resistor 18, and reference numeral 20. The second connection circuit shown is for electrically connecting the DC bias voltage power supply 17 and the second toner recovery roller 22 directly directly, and both of these connection circuits are connected to the power supply 17. They are connected in parallel.

In any case, a negative bias voltage is applied to the first cleaning brush 11 via the resistor 18 and the toner collecting roller 21, and the second cleaning brush 22 is provided with the toner collecting roller 22. Similarly, a negative bias voltage is applied via the. As a result, the first cleaning brush 11
A cleaning electric field is formed between the photoconductor 1 and the photoconductor 1 such that the residual toner on the photoconductor 1 is electrostatically attracted toward the cleaning brush. Also, a similar cleaning electric field is formed between the second cleaning brush 12 and the photoconductor 1.

First and second cleaning brushes 11,
As described above, the bias voltage having the same polarity and the bias voltage having the opposite polarity to the toner to be neutralized is applied to the DC bias voltage source 12 and the DC bias voltage power source 17 shown in FIG. The circuits 19 and 20 constitute such bias voltage applying means. Then, this means applies a bias voltage of a magnitude different from the bias voltage applied to the first cleaning brush 11 to the second cleaning brush 11.
It also serves as a means for applying to the cleaning brush 12. In the case of the present example, such an applying unit applies the second voltage rather than the bias voltage applied to the first cleaning brush 11.
The application means is such that the bias voltage applied to the cleaning brush 12 is larger. That is, it is a means for applying to the second toner collecting roller 22 a bias voltage that is higher than the bias voltage applied to the first toner collecting roller 21.

Here, the photosensitive member 1 is, for example, a so-called N in which the photosensitive layer 1b is provided on the surface of the conductive layer 1a as shown in FIG.
The toner T after the toner image transfer process and the transfer paper separation process described above remains on the surface of the photosensitive layer 1b. The residual toner is generated during the transfer process and the separation process. Since it is subjected to a charging action at that time, positive and negative polarities are mixedly present. The surface of the photoconductor 1 is also positively and negatively charged.

When such a toner T passes through the facing portion of the pre-cleaning static eliminator charger 15 (FIG. 1), the pre-cleaning static eliminator charger 15 makes the positive polarity uniform by performing the positive corona discharge. Further, the cleaning lamp 9 emits light, and this light irradiates from the pre-cleaning charge removal charger 15 to the vicinity immediately below the first cleaning brush 11. Such light is incident on the back surface of the photoconductor 1 and immediately below the positively charged toner T, the negative charge on the photosensitive layer 1b, which has given electrostatic attraction to the toner, is made to disappear. . That is, the photoconductor 1 after passing through the pre-cleaning charge removal charger 15 is in the charge holding state as shown in FIG. Incidentally, in FIG. 3, what is indicated by reference numeral 23 is the charge of the photosensitive layer 1b which generates the attraction force described above, but this negative charge disappears as shown in FIG. In this manner, as shown by reference numeral 24 in FIG. 4, charges that generate an image force are generated in the conductive layer 1a. The photoconductor 1 has a light-transmitting property that allows the light from the cleaning lamp 19 to pass therethrough.

When the pre-cleaning charger 15 performs the pre-cleaning process in this manner, the distribution of the charge amount (charge amount per unit weight) of the toner to be cleaned is as shown in FIG. Become.

Here, the cleaning / charge removing charger 1
The surface potential of the photoconductor that has received the charging action of No. 5, that is, the potential of the photoconductor surface after the cleaning pretreatment is +300 V
(FIG. 4). On the other hand, when the output of the DC bias voltage power supply 17 is set to, for example, −400V, the bias voltage of −400V is applied to the second toner collecting roller 22. On the other hand, a bias voltage of −100 V, for example, is applied to the first toner collecting roller 21. The resistor 18 is selected to have a resistance value that gives such a bias voltage. In any case, the second
Therefore, a larger bias voltage is applied to the toner collecting roller 22 than to the first toner collecting roller 21.

First and second toner collecting rollers 21 and 2
2 is a conductive roller made of, for example, stainless steel alone, or a roller body formed by coating a stainless steel cored bar with, for example, a fluorine resin in a tubular shape in order to achieve a predetermined high resistance. What is done is used.

In any case, each toner collecting roller 2
Cleaning brush 11,
Bias voltage can be applied to the first toner collecting roller 21 and the second cleaning brush 11, and between the second toner collecting roller 22 and the second cleaning brush 12, respectively. A predetermined potential difference (electric field) may be generated. As a result, when the toner adheres to the first cleaning brush 11, the toner is electrostatically attracted to the first toner recovery roller 21 and is recovered to the same roller 21. Further, when a predetermined potential difference is generated between the second toner collecting roller 22 and the second cleaning brush 12, and the toner adheres to the cleaning brush 12, this toner collects the second toner. It is electrostatically attracted to the roller 22 and collected by the roller 22.

If the applied voltage of the first toner collecting roller 21 is -100V, the core metal potential of the first cleaning brush 11 is -50V, for example. On the other hand, the surface potential of the photoconductor 1 moving directly below the first cleaning brush 11 is + 300V.

The potential of the first cleaning brush 11 is
As described above, when the surface potential of the photoconductor is + 300V at −50V, the potential difference between the first cleaning brush 11 and the photoconductor 1 becomes −350V.
That is, the cleaning electric field has such a value.

As described above, FIG. 2 shows the distribution of the charge amount of the toner to be cleaned. The toner is subjected to the transfer and separation electric fields and is not cleaned yet. Since the static elimination charger 15 is affected by the corona discharge, the charge amount distribution becomes a distribution with a wide base. That is, with the same polarity, the charge amount distribution has a broad shape.

According to this characteristic diagram, the charge amount of the toner in the E portion is small, and such a toner is
It is removed by the first cleaning brush 11 which causes a potential difference of −350 V with the photoconductor. Since the toner in the area E has a small amount of charge, the image force between the toner and the photoconductor 1 is small and relatively easy to remove. On the other hand, its polarity is reversed in a strong electric field with a high potential difference. It is also a toner that is easy to do.

The above-mentioned relatively small potential difference of −350 V (compared with the later-described one) is not suitable for removing the toner (toner having a high image force) whose charge level is strong, but With respect to the toner having a weak charge degree (the toner in the E portion), the potential difference is such that the toner can be satisfactorily removed without reversing the polarity.

The toner thus electrostatically attracted to the first cleaning brush 11 and scraped off from the surface of the photosensitive member is further electrostatically attracted to the first toner collecting roller 21. After being scraped off from the surface of the roller 21 by the scraper member 5, the scraper member 5 stores the toner in a toner collecting bottle (not shown) by an auger 26 provided in the toner discharging and conveying path 25.

The surface potential of the photoconductor 1 after passing through the portion of the first cleaning brush 11 changes according to the current flowing from the cleaning brush 11 to the photoconductor 1, but according to the experiment of the present inventor. For example, it was confirmed that the current was almost zero, and no change in the potential due to the cause was observed. It is considered that this is because the voltage applied to the first cleaning brush 11 is relatively low, so that almost no current flows from the brush 11 to the photoconductor 1.

Here, when the output voltage of the DC bias voltage power supply 17 is set to -400 V, the second cleaning brush 12 to which the voltage is applied via the second recovery roller 22.
The core metal potential of is, for example, −350V. When the core metal potential of the second cleaning brush 12 has such a value, the potential difference between the photoconductor 1 having a surface potential of +300 V and the cleaning brush 12 is −650 V. Under such a cleaning electric field, the toner in the F portion shown in FIG. 2 is removed by the second cleaning brush 12.

The toner in the F portion has a large amount of charge (the degree of charging strength), and the image force generated between the toner and the photoconductor becomes large. Therefore, a stronger cleaning electric field is applied to the cleaning portion. Without action, such toner cannot be removed. Even if the cleaning electric field is increased, the toner in the F portion is biased to the one having a larger positive charge amount, so that the polarity is less likely to be inverted as compared with the toner in the E portion, and the margin is large. It is getting bigger. In any case, the potential difference of −650 V is a potential difference that can satisfactorily remove the toner in the F portion without reversing the polarity. In the case of this example, first, the toner in which the polarity reversal easily occurs is removed by the first cleaning brush 11, and thereafter, the toner in which the polarity reversal hardly occurs is removed by the second cleaning brush 12. As a result, the residual toner on the photoconductor can be unevenly removed.

In the embodiment shown in FIG. 1, the first cleaning brush 11 located upstream with respect to the moving direction of the photosensitive member 1 is more likely than the second cleaning brush 12 located downstream thereof. Since the low voltage is applied, it is possible to prevent the charging polarity of the residual toner that is in contact with the first cleaning brush 11 from being reversed, and thus the residual toner that is not removed by the brush 11 is removed by the second cleaning brush 12. It can be removed efficiently.

In any case, in the structure in which the bias voltages having different polarities are applied to the two cleaning brushes, the toners having the same polarity as described above but having different charge amounts or the polarity reversal easily occurs. It is difficult to remove the toner separately from the toner and the toner whose polarity reversal does not easily occur. The toner that is electrostatically sucked and adhered to the second cleaning brush 12 is collected by the second toner collecting roller 22, and then scraped off from the surface of the roller 22 by the scraper member 6. ,
An auger 28 provided in the toner discharge / transport path 27 stores the toner in a toner recovery bottle (not shown) outside the cleaning device.

The toner collecting rollers 21 and 22 are attached to the first and second cleaning brushes 11 and 12 shown in FIG.
It is also possible to directly connect, for example, the connection circuits 19 and 20 without directly interposing them, and to apply bias voltages of different magnitudes directly to the respective cleaning brushes. Further, without providing the toner collecting roller, for example, each cleaning brush 1
It is also possible to bring a flicker or the like into contact with 1 and 12 to remove the toner attached to the cleaning brush. On the other hand, when the toner collecting rollers 21 and 22 are used, the toner is electrically attracted, so that the toner collecting property is improved and the cleaning brush can be prevented from deteriorating. .

Further, as the bias voltage applying means, by using the means composed of the DC bias voltage power supply 17, the both connection circuits 19 and 20 connected in parallel to each other, and the like, only one bias voltage power supply is required. Therefore, compared to a configuration in which bias voltages are applied to the cleaning brushes or the toner collecting rollers by separate bias voltage power supplies, the configuration of this type of cleaning device can be simplified, and the cost can be reduced. Will also be advantageous.

The present invention provides at least two cleaning brushes as described above, and three or more cleaning brushes may be provided so as to obtain the same operation as described above.

In addition to the apparatus for cleaning an image bearing member such as a photosensitive member on which an electrostatic latent image is formed, the present invention also primarily transfers a toner image on the photosensitive member to an intermediate transfer member,
After that, the present invention can also be applied to a cleaning device for removing the toner remaining on the intermediate transfer member in the image forming apparatus of the type in which the toner image is secondarily transferred to the recording medium. In this case, the intermediate transfer body is the image carrier that is the cleaning target.

[0052]

According to the cleaning device of the first aspect, the toner having a variable charge amount can be removed satisfactorily, so that the toner is not left unremoved, thereby causing the background stain on the image. Can be suppressed and the image quality can be further improved.

According to the cleaning device of the second aspect, the residual toner, which has a small charge amount and is liable to cause the reversal of the charge polarity, is first removed by the first cleaning brush, and then by the second cleaning brush. Since the residual toner whose polarity is relatively hard to reverse is removed, the residual toner on the image carrier can be removed more efficiently.

According to the cleaning device of the third aspect, the toner having the varied charge amount can be removed well, so that the residual toner is eliminated and the occurrence of background stain on the image is suppressed. Therefore, the image quality can be further improved, and since the toner collecting roller is used, the toner collecting property is improved and the cleaning brush can be prevented from deteriorating.

According to the cleaning device of the fourth aspect, the structure of the cleaning device can be simplified and the cost thereof can be further reduced.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram of a cleaning device according to an embodiment of the present invention.

FIG. 2 is a diagram showing a charge amount distribution of toner to be cleaned.

FIG. 3 is an explanatory view schematically showing a photoconductor to be cleaned by the present cleaning device in an enlarged manner.

FIG. 4 is an explanatory diagram showing a charge holding state of a photoconductor before a cleaning step.

FIG. 5 is a configuration diagram of an experimental machine used to confirm the effect of the present cleaning device.

FIG. 6 is a diagram showing a difference in toner charge amount distribution after development and after charge removal.

FIG. 7 is a diagram showing a difference in toner charge amount distribution after recharge and after charge removal.

FIG. 8 is a diagram showing a difference in toner charge amount distribution after recharging and after recharging.

[Explanation of symbols]

 10 Cleaning Device 11 First Cleaning Brush 12 Second Cleaning Brush 17 Bias Voltage Power Supply 18 Resistor 19 First Connection Circuit 20 Second Connection Circuit 21 First Toner Recovery Roller 22 Second Toner Recovery Roller

Claims (4)

[Claims] 1. A first cleaning brush for rubbing the surface of an image carrier to scrape and remove the toner remaining on the surface of the image carrier after the toner image transfer step while electrostatically attracting the toner. It is provided on the downstream side in the moving direction of the image carrier with respect to the first cleaning brush, and likewise scrapes while rubbing the surface of the image carrier to electrostatically attract the residual toner. A second cleaning brush to be removed, and a first
And a bias voltage applying unit that applies a bias voltage having the same polarity and a polarity opposite to that of the toner to be removed to the second cleaning brush. A cleaning device for an image forming apparatus, wherein the cleaning device is a device for applying a bias voltage having a magnitude different from that of the bias voltage applied to the first cleaning brush to the second cleaning brush. 2. The image forming according to claim 1, wherein the bias voltage applying unit is a unit that applies a bias voltage larger than a bias voltage applied to the first cleaning brush to the second cleaning brush. Equipment cleaning device. 3. A first cleaning brush for rubbing the surface of the image bearing member to electrostatically attract and remove the toner remaining on the surface of the image bearing member after the transferring step, and a first cleaning brush. The cleaning brush of No. 1 is provided on the downstream side in the moving direction of the image carrier, and similarly, the surface of the image carrier is rubbed to electrostatically attract and remove the residual toner. The second cleaning brush is in contact with the second cleaning brush, and the first cleaning brush is in contact with the first cleaning brush, and the first toner recovery roller is configured to electrostatically attract and collect the toner attached to the cleaning brush. The toner having the same polarity as the bias voltage of the second toner collecting roller that electrostatically attracts and collects the toner adhered to the toner and the first and second toner collecting rollers that should be removed. Bias voltage applying means for applying a bias voltage having a polarity opposite to that of the bias voltage applied to the first toner collecting roller by the second bias voltage applying means.
And a cleaning device for the image forming apparatus. 4. The bias voltage applying means includes a bias voltage power supply, a first connection circuit for electrically connecting the bias voltage power supply and the first toner collecting roller through a resistor, and the bias voltage power supply. And a second toner recovery roller, and a second connection circuit for electrically and directly connecting the first and second toner collection rollers, respectively, and the first and second connection circuits are connected in parallel. Item 3. A cleaning device for an image forming apparatus according to item 3.