JPS63155081A - Cleaning device for image forming device - Google Patents

Abstract

PURPOSE:To prevent the leakage of electric current even in case of the use of a low-resistance carrier to improve the efficiency of toner recovery by electrifying a dielectric of a toner recovering means with the same polarity as the voltage applied to a core member. CONSTITUTION:A recovery roller 37 consists of a conductive core member 38 and a dielectric 39 stuck to the outside of the member 38, and the toner stuck to a carrier 33 is attracted to the recovery roller by an electric force and is stuck to the surface of the dielectric 39. Since the carrier 33 and the core member 38 are electrically insulated from each other because of the presence of the dielectric, the electric current is not leaked through the carrier though the volume specific resistivity of the carrier 33 is low. A conductive brush 40 is brought into contact with the surface of the dielectric 39 and the voltage from a power source 41 is applied to the dielectric 39 through the brush 40 to electrify the surface of the dielectric with the same polarity as the voltage applied to the core member 38, and thus, the toner stuck to the carrier 33 is attracted by not only the action of the electric field of the core member but also the electric charge on the surface of the dielectric 39 to efficiently recover the toner to the recovery roller 37.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a cleaning device in an image forming apparatus that cleans toner remaining on a latent image carrier after transferring a toner image formed on the latent image carrier to a transfer material. In particular, there is a cleaning sleeve that houses a magnet inside and supports the carrier with its magnetic force, and a bias voltage is applied to the cleaning sleeve so that the residual toner on the latent image carrier can be attracted to the carrier on the cleaning sleeve by electric force. The present invention relates to a cleaning device having a voltage applying means for applying voltage and a toner collecting means for collecting cleaned toner from a cleaning sleeve side.

In an image forming apparatus, such as a copying machine, a printer, or a facsimile machine, which repeatedly performs the process of forming a toner image on a latent image carrier and transferring it to a transfer material, the latent image carrier after the toner image transfer is used. It is necessary to clean the toner remaining on the surface and prepare for the next toner image forming process. The use of cleaning devices of the above type for this purpose has been well known (for example, Japanese Patent Publication No. 48-37382, Japanese Patent Application Laid-Open No. 56-51
(See Publication No. 768, Japanese Unexamined Patent Application Publication No. 50-75044, etc.)
. This type of cleaning device, commonly referred to as a magnetic brush cleaning device, applies a bias voltage to a cleaning sleeve to electrically attract residual toner to the carrier on the sleeve.

This is to remove residual toner from the latent image carrier.

The toner transferred to the cleaning sleeve side is collected by a toner collecting means.

Conventionally, as a toner collecting means, a collection roller made of a conductive metal that is rotationally driven is often used, and a bias voltage of the same polarity but higher than the voltage applied to the cleaning sleeve is applied to this roller. An electric field is formed between the sleeve or the carrier thereon and the first collection roller, and the toner present in this electric field is attracted to the collection roller side by electric force, thereby collecting the toner.

By the way, in order to enhance the cleaning effect in the above-mentioned type of device, the specific volume resistivity of the carrier supported on the cleaning sleeve is lowered to, for example, 1010Ω·l or less, particularly 10QΩ·l or less, and the bias voltage applied to the cleaning sleeve is By increasing the effective bias at the carrier tip by effectively injecting charge into each carrier particle and increasing the electric field between the carrier and the latent image carrier, the toner present in this electric field is transferred to the carrier by a strong electric force. It is desirable that the structure be configured so that suction can be carried out. However, when such a low-resistance carrier is used, the electrically conductive collection roller to which a voltage is applied and the cleaning sleeve become electrically connected via the carrier, so when the potential difference between the roller and the carrier is large, the flow through the carrier There was a risk that the carrier particles would be destroyed by the current. Conventionally, it was necessary to take measures such as reducing the potential difference between the collection roller and the cleaning sleeve, but this would weaken the electric field between the collection roller and the carrier (or sleeve) and remove the toner. The disadvantage is that the recovery efficiency is reduced. Therefore, a dielectric material is laminated around a conductive core member, and a voltage is applied to the core member to form an electric field between the low-resistance carrier and the core member, and the toner adhering to the carrier is transferred to the surface of the dielectric material using electric force. A configuration has been proposed that collects toner by attracting it. According to this configuration, since the dielectric exists between the carrier on the cleaning sleeve and the conductive member, it is possible to prevent leakage through the carrier. However, this configuration has the disadvantage that the electric field between the core member and the carrier is weakened, resulting in a decrease in toner recovery efficiency. This weakening of the electric field is thought to be due to dielectric polarization of the dielectric material present in the electric field.

SUMMARY OF THE INVENTION The object of the invention is to provide a cleaning device of the type mentioned at the outset, which eliminates the drawbacks of the prior art mentioned above.

In order to achieve the above object, the present invention proposes a structure in which a charging means is provided for charging the dielectric of the toner collecting means to the same polarity as the voltage applied to the core member.

Embodiments of the present invention will be described below with reference to the drawings, and the above-mentioned conventional configuration will be explained more specifically with reference to the drawings.

FIG. 1 is a schematic sectional view showing an example of an image forming apparatus (electronic copying machine) equipped with a cleaning device according to the present invention.
In order to understand the present invention, the outline of the configuration shown here will first be briefly explained.

In the copying machine illustrated in FIG. 1, a document 2 is placed on a contact glass 1 fixed to the upper part of the main body, and a light source (flash lamp) 3a covers the entire surface of the document 2.

3b, and simultaneously projects the entire image on the document surface onto a latent image carrier configured as an endless belt-shaped photoreceptor 4. The endless belt photoreceptor 4 includes a driving roller 5 and three driven rollers 6.7.8.
The hook has been passed. A predetermined tension is applied to the belt photoreceptor 4 by a spring. Further, the photoreceptor 4 and other elements constitute a photoreceptor unit, and this unit is configured to be pulled out to the front by upper and lower slide rails 10 and 11. Each roller shaft end of the photoreceptor unit.

It is supported by front and rear unit side plates (not shown). A drive motor 12 is supported on the rear unit side plate, and the motor 12 independently drives the belt photoreceptor 4 via the drive roller 5.
to drive and control.

At the start of the copying operation, the drive motor 12 and the main motor (not shown) start operating the paper feeding device, cleaning device 28, and other elements described later, and at the same time, the belt photoreceptor 4 rotates in the direction of the arrow. When the mark detection sensor 13 detects a synchronization mark (not shown) provided on the side end of the belt photoreceptor, the image forming elements around the belt photoreceptor start operating at a set timing. That is, first, the surface of the photoreceptor is charged to a predetermined polarity by the 1F electric charger 14. In this example, an organic semiconductor (○pc) photoreceptor 4
is used, so a negative 1F current is applied.

On the other hand, as described above, the reflected light from the original that has been entirely exposed by the light sources 3a and 3b is reflected by the first mirror 15. The light passes through the lens 16 and the second mirror 17 and is irradiated onto the exposed surface of the belt photoreceptor 4, whereupon the original image is formed.

In this way, an electrostatic latent image corresponding to the image of the original is formed on the surface of the photoreceptor, and this latent image reaches the developing device 18 as the photoreceptor 4 rotates. visualized). In this example, the toner is charged to a polarity opposite to that of the electrostatic latent image on the photoreceptor 4, and electrostatically adheres to the latent image to form a toner image. The developer used in the developing device 18 may be a two-component developer containing toner and a carrier, or a one-component developer containing no carrier.

The toner image formed as described above is transferred to the paper feeder 19.
, 20, 21, the transfer material (usually transfer paper) in the paper feeding device corresponding to the selected size is supplied to the transfer section 9 as shown by arrows A, B, or C. The transfer material that has reached the transfer section 9 is negatively charged from one side by the discharge of the transfer charger 22, and is irradiated with light from the back side of the photoreceptor 4 by the static elimination lamp 23, removing the toner on the photoreceptor. The image is transferred to a transfer material. The transfer material is then separated from the photoreceptor 4. At that time, the roller diameter of the roller 7 is, for example, 26
If the transfer material is as small as mm, it is possible to separate the transfer material from the photoreceptor 4 by the curvature using the stiffness of the paper, but in the example shown in Figure 1, the AC separation charger 24 is used to separate the transfer material to increase reliability. It is reliably separated from the photoreceptor 4. It is well known that a transfer device other than the transfer charger 22 may be used.

The transfer material onto which the toner image has been transferred passes through the fixing device 25 (
Arrow D), the toner image is fixed here.

The paper is then discharged onto the paper discharge tray 26 as shown by arrow E.

The residual toner remaining on the photoreceptor 4 after transfer reaches cleaning 1428, where the charge is first made uniform by the pre-cleaning charger 27. In this example, the residual toner is positively charged by the charger 27 and then cleaned from the surface of the photoreceptor. In this manner, the next toner image forming step can be performed. FIG. 2 schematically shows the residual toner on the photoreceptor 4 that has passed through the charger 27.

As indicated by the symbol T, the diameter of the toner particles is usually about several tens of microns.

The reason why the residual toner is uniformly charged to a positive polarity by the pre-cleaning charger 27 is that the toner is charged to the separation charger 2.
4, the charge polarity is not constant, and the transfer conditions are not necessarily constant depending on the thickness of the transfer material, environment, etc., so the charge on the toner before reaching the charger 27 is This is because the amount may vary. Further, when the transfer material is not sent to the transfer position 9 due to transportation trouble, all the toner on the photoconductor 4 that has reached the transfer position is not transferred, and the entire toner is negatively charged by the transfer charger 22. Even in such a case, the toner can be positively charged by the charger 27.

By repeating the copying cycle described above.

Transfer materials on which toner images are formed can be sequentially obtained.

As clearly shown in FIG. 2, the cleaning device 28 includes, in addition to the charger 27, a cleaning sleeve 31 that faces a backup roller 30 disposed on the back side of the belt photoreceptor 4 with the photoreceptor 4 in between. The sleeve is rotated clockwise. The backup roller 30 is
The photoreceptor portion located between the roller 30 and the sleeve 31 is located not directly below the cleaning sleeve 31 but slightly to the left in FIG. .

Area facing sleeve 31 (cleaning nip width)
is expanding.

A suitable number of magnets 32 are housed inside the cleaning sleeve 31, and these magnets 32 are fixed in position so that S poles and N poles alternately appear on the side facing the inner peripheral surface of the sleeve 31. It is located. On the surface of the sleeve 31, a carrier 33 consisting of particles with a diameter of, for example, about 120 μm is placed, similar to the carrier carried on the image sleeve of a dry developing device. In this example, the carrier particles are preliminarily immobilized with toner. electrically attached.

This carrier and toner are generally referred to as cleaning agents. The sleeve 31 is made of a conductive non-magnetic material, for example aluminum.

As shown schematically in FIG. 3 with reference numeral 33, each particle of the carrier has a core 34 made of a magnetic material such as iron.
and a coat 35 mainly made of resin, for example. The toner adhering to the carrier 33 on the sleeve 31 is indicated by the symbol t in FIG. 3 in order to distinguish it from the residual toner T on the photoreceptor 4. In this way, since the core 34 is a magnetic material, the carrier 33 is attached to the magnet +-3 installed inside the sleeve 31.
When the sleeve 31 rotates clockwise in FIG. 2, it is conveyed in the same direction as the sleeve while forming a magnetic brush on the circumferential surface of the sleeve. In this example, the toners t and T are non-magnetic toners, but magnetic toners may also be used. In the case of magnetic toners, the toner t on the sleeve 31 is also attracted to the sleeve 31 side by the magnet 32. (be able to.

Further, a negative bias voltage having a polarity opposite to the charged polarity of the residual toner T(7) that has passed through the charger 27 is applied to the cleaning sleeve 31 by a voltage applying means, in the example shown in the figure, a power supply 36. A negative charge is injected into the carrier particles 33 (see FIG. 3).

In this example, Den i1? The voltage applied by X36 is -170cm.

Residual toner T that has passed through the charger 27 before cleaning
When the toner T reaches the vicinity of the cleaning sleeve 31 due to the travel of the three-photo element 4, this toner T is positively (temporarily charged), so it is attracted by the electric force to the negatively charged carrier 33, which is the opposite, and is transferred to the photoreceptor. 4 and attaches to the carrier 33. More specifically, the sleeve 31 and the carrier 33
Since a negative voltage is applied to the photoreceptor 4 and the base layer of the photoreceptor 4 is grounded, an electric field is formed between them, and the positive residual toner T present in this electric field is statically transferred to the carrier 33, that is, the magnetic brush. The transition is electronic. The carrier 33 in the portion of the sleeve 31 facing the photoreceptor 4 and the surface of the photoreceptor 4 may be slightly separated from each other, or may be in contact with each other. Further, in the illustrated example, the carrier 33 on the sleeve 31 and the toner t are stirred and mixed with each other by the rotation of the sleeve 31, and the coat 35 of the carrier 33 has a negative polarity.
The toner t is frictionally charged to a positive polarity, and since the toner t and the carrier 33 are moving while shifting their positions relative to each other, the charge on the carrier due to this friction also causes
The residual toner T is sucked into the carrier 33.

The toner transferred from the photoreceptor 4 to the carrier 33 side is conveyed together with the carrier as the sleeve 31 rotates, and is transferred to the second
As shown in the figure, it is collected by a collection roller (scavenge roller) 37 according to the present invention, which is placed opposite to the sleeve 31. Details regarding toner collection will be revealed later.

The toner transferred to the collection roller 37 is scraped off from the roller 37 by a blade 42 pressed against the surface of the roller 37, falls into a toner receiver 43, and is then carried out by a coil conveyor 44.

As shown in FIG. 4, the blade 42 is made of an elastic material such as fluororubber fixed to the tip of a leaf spring 45 made of phosphor bronze, for example, and the other end of the leaf spring 45 is fixedly supported by the machine frame. .

In the illustrated example, the toner on the sleeve 31 is removed from the collection roller 3.
7, not all of the toner is collected by the roller 37, but a predetermined amount of toner adheres to the carrier and remains on the sleeve 31 as it passes through the roller 37.

This remaining toner becomes the aforementioned toner t constituting a part of the cleaning agent, and due to the friction between the toner t and the carrier 33, the carrier is triboelectrically charged and attracts the remaining toner T.

As described above, the sleeve 31 is placed opposite the photoreceptor 4 so that the carrier on the sleeve 31 can suck the residual toner T on the photoreceptor 4, and the residual toner T is cleaned. The lower the specific volume resistivity (more precisely, the volume specific resistivity of at least the surface portion of each carrier particle, in the example shown, the coat 35), the more the electric charge due to the voltage applied to the sleeve 31 will be applied to the most advanced carrier on the sleeve 31. The toner is effectively injected into the particles, which strengthens the electric field between the carrier and the photoreceptor base layer and increases the effective bias at the carrier tip, which makes it possible to attract the residual toner T with a strong electric force and improve the cleaning effect. It is possible to increase FIG. 5 is an example of a graph showing the relationship between the specific volume resistivity of the carrier and the cleaning rate of residual toner on the photoreceptor. As you can see, the specific volume resistivity of the carrier is less than 1010Ω・Cff1, especially 109
When the resistivity is Ω·− or less, the cleaning rate increases, and conversely, when the resistivity becomes higher than the above value, the cleaning rate decreases. The cleaning rate shown here is expressed as follows, where X is the amount of residual toner entering the cleaning device, and Y is the amount of residual toner after passing through the cleaning device, that is, the amount of toner that could not be cleaned. It means percentage (%). However, although some of the toner that has once transferred to the carrier 33 may be returned to the photoreceptor 4, the graph in FIG. 5 ignores the amount of this returned toner.

As mentioned above, under other conditions being the same, it is advantageous that the lower the specific volume resistivity of the carrier, the higher the cleaning rate can be. However, if this is too low, the sleeve 31
Since frictional charging between the upper carrier 33 and the toner T becomes difficult to occur, and the efficiency of cleaning the residual toner T due to the frictional charging of the carrier decreases, it is generally particularly preferable that the specific volume resistivity of the carrier is in the range of 10 to 10 Ω. From this point of view, in this example, the volume resistivity of the carrier 33 supported on the cleaning sleeve 31 is set to 10 IlΩ·am.

However, when such a low-resistance carrier is used, and the collection roller is made of a conductive material such as metal as in the past, there is a risk that the carrier coat may be destroyed, as described above.

In order to understand the present invention, the above-mentioned conventional drawbacks will be explained based on the drawings. As schematically shown in FIG. 10, a conventional collecting roller 3 is made entirely of metal and rotates in a clockwise direction.
7a, a voltage higher than the voltage applied to the sleeve 31 is applied by the power source 41a. However, roller 3
7 and the sleeve 31, and if the polarity of the toner attached to the carrier 33 is positive as in FIG. 2, a negative voltage is applied to the collection roller 37a and the sleeve 31. Ru. Therefore, an electric field is applied between the negatively charged carrier 33 and the single collection roller 37a by applying a voltage to the sleeve 31.

The positively charged toner present in this electric field is attracted to the collection roller 37a side by electric force, adheres to the roller 37a, and is collected. In such a configuration, if the specific volume resistivity of the carrier 33 is low (for example, 10 8 Ω·cm), the first
As can be seen from Figure 0, the sleeve 31 is inserted through this carrier.
The roller 37a becomes electrically conductive and leakage occurs.

Therefore, if the potential difference between the sleeve 31 and the collection roller 37a is high as in the example shown in FIG. Functionality will be lost. Carrier 33 on sleeve 31 and collection roller 37
The same is true when the rollers 37a are arranged so that a is slightly apart. For this reason, the metal recovery roller 37a
When using, the volume resistivity is, for example, 1015Ω・
It is necessary to use one or more high-resistance carriers or to make the potential difference between the roller 37a and the sleeve 31 low (for example, about 20 V) to suppress the current flowing through the carrier 33 and prevent the carrier from being destroyed. However, if a high-resistance carrier is used as in the former case, the cleaning rate will decrease as seen in FIG. 5, and if the potential difference is set low as in the latter case, the electric field effect between the collection roller 37a and the carrier will decrease The efficiency of collecting toner to the roller 37a decreases. When the toner recovery performance deteriorates, the ratio of toner in the cleaning agent on the sleeve 31 gradually increases, the effect of charge injection into the carrier and the charging ability decrease, and cleaning failure occurs.

Accordingly, in the configuration according to the present invention, the collection roller 37 has a conductive core member 38 made of metal or the like formed in a cylindrical shape, and a conductive core member 38 formed in a cylindrical shape, and The core member 38 is connected to a power supply so that the toner attached to the carrier 33 on the sleeve 31 is drawn toward the collection roller 37 by electric force, as in the case of FIG. 10. A bias voltage is applied by 41, and the polarity of this voltage is the same as the voltage applied to the cleaning sleeve 31, but in the example of FIG. The collection roller 37 is rotated clockwise.The carrier 33 supported on the part of the sleeve 31 facing the collection roller 37 and the surface of the collection roller 37, that is, the surface of the dielectric 39, They may be in contact with each other as in the case of FIG. 10, or they may be slightly spaced apart.

According to the above-mentioned configuration, as in the case of FIG. 10, since there is a difference in the voltage applied to the core member 38 and the sleeve 31, the part of the sleeve 31 facing the collection roller 37 or the carrier 33 supported here An electric field is formed between the collecting roller 37 and the conductive core member 38 of the collection roller 37, and exists in this electric field as is clear from FIG. The toner adhering to the carrier 33 is drawn toward the [10-la side by the electric force and adhering to the surface of the dielectric material 39. In this way, the toner is collected by the collection roller 37. At this time, unlike in FIG. 10, since a dielectric 39 exists between the core member 38 and the carrier 33, the carrier 33 and the core member 38 are electrically insulated from each other. Therefore, even if the specific volume resistivity of the carrier 33 is as low as 10' Ω·Cm and the difference between the voltages applied to the core member 38 and the sleeve 31 is large, no current leaks through the carrier. Therefore, the carrier coat is not destroyed by leakage current, and the drawbacks of the conventional structure shown in FIG. 10 can be eliminated.

However, if the dielectric 39 exists in the electric field between the carrier 33 and the core member 38, the electric field between the carrier 33 and the core member 38 weakens, and the efficiency of toner collection to the first collection roller 37 decreases. The reason why the electric field weakens is that the dielectric 39
The core member 38 and the carrier 33 or the sleeve 3
This is thought to be due to dielectric polarization caused by the action of the electric field between the two. Therefore, in the present invention, in addition to adopting a configuration in which a dielectric is interposed in the electric field to prevent leakage, a conductive brush 40 is brought into contact with the surface of the dielectric 39 as illustrated in FIGS. 2 and 6. , the voltage from the power supply 41 is applied to the brush 4
A configuration is adopted in which the voltage is applied to the dielectric material 39 through the voltage applied to the core member 38, and the surface of the dielectric material is charged to the same polarity as the voltage applied to the core member 38, that is, a polarity different from that of the toner t on the carrier (negative polarity in this example). are doing. If the surface of the dielectric material 39 is thus charged to a polarity opposite to that of the toner, the toner adhering to the carrier 33 will be charged in addition to the action of the electric field described above.

The electric charge on the surface of the dielectric 39 also causes it to be attracted to the surface of the dielectric 39 by an electric force. The brush 40 is made of a conductive material such as stainless steel, extends in the axial direction of the collection roller 37, and is fixed to the machine frame via an insulator 46 (FIG. 2). With such a configuration, it is possible to compensate for a decrease in electric field strength and efficiently collect toner to the collection roller 37. Naturally, leakage through the carrier 33 can also be prevented.

The dielectric layer 39 can be formed by applying a layer of, for example, epoxy resin to the core member 38 made of a metal roller, or by wrapping a suitable dielectric sheet or tube such as polyester or fluorinated resin around the core member 38. Alternatively, the dielectric body 39 can also be formed by covering and fixing.

The thickness of the dielectric layer is set to, for example, about 200μ.

In the above embodiment, the power source 41 applies voltage to the core member 38.
and the brush 40 constitute a charging means for charging the dielectric 39, and a bias voltage of the same potential is applied to the core member 38 and the dielectric 39, but the voltage may be applied by separate power supplies, or The potential levels may be different from each other. Further, as shown in FIG. 8, a conductive blade 142 made of, for example, a thin metal plate is used as a blade for scraping off the toner adhering to the collection roller 37 in contact with the surface of the dielectric 39. A voltage may be applied to the dielectric 39 by. If the conductive member for voltage application is configured to also serve as a toner scraping blade, the structure can be simplified, which is advantageous. Furthermore, it is also possible to charge the surface of the dielectric with a corona discharger.

In the example shown in FIG. 2, the collection roller 37 is composed of an insulating cylindrical core member 38 and a dielectric member 39 fixed to the outside thereof and disposed at a position facing the cleaning sleeve 31. The brush 40 constitutes the toner collection means, but as shown in FIG. 9, a conductive roller 138 is also used.

A dielectric material consisting of a belt 139 is wound around another roller 238, and this belt 139 is rotated by the roller 138° 238, a voltage is applied to the roller 138, and the surface of the belt 139 is coated with a conductive member such as a brush 40. It may also be configured to be electrically charged via. Even in this configuration, the dielectric material made up of the belt 139 is
It is located on the outside of the conductive core member 38 and opposite the cleaning sleeve 31. roller 138
It is also possible to stop the belt 139 and rotate the belt 139 while slinging it around the roller 138. In short, it is sufficient that at least the dielectric body of the dielectric body and the core member is rotatable. Furthermore, the same effect as in the previous embodiment can be obtained by using a dielectric layer on the outside of the belt 139 and a conductive layer on the inside, and applying a voltage to the conductive layer and charging the dielectric layer.

Further, the present invention can be applied to a cleaning device in which, for example, the cleaning sleeve is fixed without rotating, and a magnet installed inside the sleeve is rotated to convey the cleaning agent, or the sleeve and magnet are both driven to rotate. The same applies to cleaning devices such as image forming apparatuses using a drum-shaped photoreceptor or image forming apparatuses using a latent image carrier made of a dielectric material. In this case, it goes without saying that the charging polarity of the latent image carrier used, the charging polarity of the toner during development, and the polarity of the bias voltage applied to each sleeve may change depending on the properties of the latent image carrier used. For example, when a selenium-based photoreceptor is used, the photoreceptor is normally charged to a positive polarity by the 'JtF Wi charger 14, and the toner during development is normally charged to a negative polarity. Then, the residual toner may be charged to a negative polarity, and a positive voltage may be applied to the sleeve 31 and the core member 38. At this time, the polarity with which the dielectric 39 of the collection roller 37 or the belt 139 is charged is also positive, which is opposite to the charging polarity of the toner.

According to the present invention, since a dielectric material is placed on the outside of the conductive core member, leakage can be prevented even when a low resistance carrier is used, and in addition to the electric field effect based on the voltage applied to the core member. Since toner can be collected by the action of charging the dielectric, toner collection efficiency can be improved.

[Brief explanation of the drawing]

FIG. 1 is a schematic sectional view showing an example of a copying machine equipped with a cleaning device according to the present invention, FIG. 2 is an enlarged sectional view showing details of the cleaning device, and FIG. 3 is an explanation schematically showing the cleaning operation. Figure 4 is a perspective view of the cleaning blade, Figure 5 is a graph showing an example of the relationship between the specific volume resistivity of the carrier and the cleaning rate, and Figure 6 is a schematic diagram of the relationship between the collection roller, cleaning sleeve, and carrier. 7 is a vertical sectional view of the collection roller, FIGS. 8 and 9 are schematic configuration diagrams showing other embodiments, and FIG. 10 is a conventional configuration example, and FIGS. It is a similar explanatory diagram. 28...Cleaning device 31...Cleaning sleeve 32...Magnet 33...Carrier 3
8... Core member 39... Dielectric material 142
...Blade T...Residual toner Fig. 9

Claims (2)

[Claims] (1) A cleaning sleeve that houses a magnet inside and supports the carrier with its magnetic force, and a bias on the cleaning sleeve so that the residual toner on the surface of the latent image carrier can be attracted to the carrier on the cleaning sleeve by electric force. The toner collecting means includes a voltage applying means for applying a voltage, and a toner collecting means for collecting cleaned toner from the cleaning sleeve side, and the toner collecting means includes a conductive core member and a conductive core member located outside the core member and facing the cleaning sleeve. at least the dielectric body of the toner collecting means is rotatable, and the conductive core member has a dielectric body disposed at a position such that the toner collecting means has a dielectric body disposed at a position such that the toner collecting means has a dielectric body disposed at a position such that the toner collecting means is rotatable. In a cleaning device for an image forming apparatus in which a bias voltage is applied to the surface so as to be drawn by an electric force, a charging means is provided for charging the dielectric of the toner collecting means to the same polarity as the voltage applied to the core member. The cleaning device characterized in that: (2) The cleaning device according to claim 1, wherein the dielectric is charged via a blade that scrapes off toner adhering to the surface of the dielectric.