JP2001188417A - Transfer device and image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a transfer device and an image forming device provided with the transfer device where a cleaning function of a transfer belt by a dielectric layer can be maintained well by controlling abnormal electrification of the dielectric layer and toner due to contact between a cleaning member with the dielectric layer and the transfer belt. SOLUTION: In a transfer device 20 provided with the transfer belt 21 that is supported by a multiple number of supporting rollers and carrying and transporting transfer material and a cleaning roller 40 cleaning the surface of the transfer belt by coming into contact with the transfer belt 21 and transferring a toner image formed on a photoreceptor drum 10 to the transfer material on the transfer belt 21, a dielectric layer is provided on the surface of the cleaning roller 40 and it is constituted so that the surface of the cleaning roller 40 and the surface of the transfer belt 21 are moved in the same direction at the same speed with a contact part of the cleaning roller 40 and the transfer belt 21.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image forming apparatus such as a copying machine, a facsimile, and a printer, and a transfer device used in the apparatus. More specifically, the present invention relates to a transfer device supported by a plurality of rotating members and carrying a transfer material. Transfer belt, and a cleaning member for cleaning the surface of the transfer belt, the cleaning member having a dielectric layer on the surface, and transferring the toner image formed on the image carrier to the transfer material on the transfer belt. The present invention relates to a transfer device for transferring images to an image forming apparatus, and an image forming apparatus provided with the transfer device.

[0002]

2. Description of the Related Art Conventionally, in an image forming apparatus such as a copying machine or a printer, a transfer device for transferring a toner image formed on an image carrier to a transfer material is provided. As this transfer device, for example, a transfer paper as a transfer material is carried by the transfer belt in a transfer area where a photoreceptor as an image carrier and a transfer belt supported by a support roller as a rotator face and contact each other. When the transfer paper passes through the transfer area, a transfer electric field is generated in the transfer area, and the transfer electric field transfers the toner image formed on the photoconductor to the transfer paper. Have been.

In the transfer device having the above-described structure, the transfer belt and the photoconductor are in contact with each other via the transfer paper. Therefore, toner on the photoconductor and toner scattered at the time of transfer adhere to the transfer belt. In some cases, such as stains on the back of the film or poor transfer. Therefore, it is indispensable to provide a cleaning unit for removing the toner attached to the transfer belt.

As a cleaning means of the transfer belt,
Conventionally, a conductive member as a cleaning member to which a cleaning bias of a polarity opposite to the charging polarity of the toner is applied,
There is known an electric field cleaning type cleaning unit that electrostatically moves toner on the transfer belt to the cleaning member by rubbing the surface of the transfer belt (for example, Japanese Patent Application Laid-Open No. 7-64444, Kaihei 9-1
52788). In the electric field cleaning method, an electric field (hereinafter, referred to as a bias electric field) is generated between the conductive member and the transfer belt, where the toner on the transfer belt exerts an electrostatic force toward the conductive member. And
Due to this bias electric field, the toner on the transfer belt moves to the cleaning member side and is removed from the transfer belt.

However, in the above-described electric field cleaning system, sufficient cleaning performance cannot be obtained, and cleaning failure may occur. In particular, when a transfer belt having a high specific resistance of 10 < ¹² > to 10 < ¹³ > [Omega] cm or more is used, or when the charge amount of the toner is large, cleaning failure easily occurs.

When using a high-resistance transfer belt,
From the fact that it is easy to be dielectrically polarized compared to a belt having a small resistance, and that the transfer charge applied to the belt during transfer, that is, the charge having the opposite polarity to the charge polarity of the toner, is more likely to be held on the applied surface. The force at which the toner is electrostatically attracted to the transfer belt increases. Further, even when the charge amount of the toner is large, the force by which the toner is electrostatically attracted to the transfer belt by the Coulomb force or the mirror image force increases. Since the toner on the transfer belt is layered, when the electrostatic attraction between the toner and the transfer belt is large, even the toner in the upper layer moves to the conductive member side due to the cleaning electric field. You may not be able to. Therefore, when the electrostatic attraction force between the toner and the transfer belt is large, in order to obtain good cleaning performance by the electric field cleaning method, it is conceivable to increase the cleaning bias applied to the conductive member.

However, if the cleaning bias is too large, dielectric breakdown may occur in the transfer belt in the thickness direction of the transfer belt at the contact portion between the cleaning member and the transfer belt, and current may leak. If a current leaks, the bias electric field is not formed, and sufficient cleaning performance cannot be obtained by the electric field cleaning method. If the cleaning bias is too large, a charge having a polarity opposite to that of the toner may be injected into the toner on the transfer belt, and the charge polarity of the toner may be inverted. Such a toner whose charge polarity has been inverted (hereinafter, referred to as an inverted toner) cannot be cleaned by the electric field cleaning method, and causes a reduction in cleaning performance.

The reversal toner is not only generated by charge injection but also adheres to the transfer belt when, for example, the reversal toner existing on the background of the photoreceptor contacts the transfer belt. In some cases, such a reversal toner also causes a reduction in cleaning performance.

[Problems to be solved by the invention]

Therefore, the present applicant can clean the transfer belt surface better than the conventional electric field cleaning system even when a high-resistance transfer belt is used or when the amount of toner charge is large. A transfer device capable of cleaning even a reversal toner and an image forming apparatus equipped with the transfer device have been proposed (Japanese Patent Application No. Hei 10 (1999) -197686).
No. 1-301773). In this transfer device, when the dielectric layer provided on the surface of the cleaning member comes into contact with the toner on the transfer belt, a charge having a polarity opposite to the charge polarity of the toner is induced on the surface of the dielectric layer by dielectric polarization, An electrostatic attraction force is generated between the dielectric layer and the toner. As a result, the layered toner sandwiched between the transfer belt and the dielectric layer has an electrostatic attraction force (hereinafter, referred to as a dielectric attraction force) between the transfer layer and the toner. An electrostatic attraction force (hereinafter, referred to as a belt attraction force) acts. And the magnitude of each electrostatic attraction force acting on the toner is
Since the toner is in inverse proportion to the square of the distance from the toner, the dielectric attraction exceeds the belt attraction for the toner in the upper layer portion of the transfer belt, and the toner is moved to the dielectric layer side and removed from the transfer belt. be able to. Therefore, even when a high-resistance belt is used or the amount of charge of the toner is large, the transfer belt surface can be cleaned better than the conventional electric field cleaning system. In addition, since a charge having a polarity opposite to the charge polarity of the toner is always induced on the surface of the dielectric layer, the toner whose charge polarity is inverted can be moved to the surface of the dielectric layer. As a result, there is no occurrence of back contamination or transfer failure of the transfer material due to transfer belt cleaning failure.

However, in the transfer device and the image forming apparatus according to the above-mentioned prior application, when the cleaning member and the transfer belt come into contact with each other, the sliding friction between the dielectric layer on the cleaning member surface and the transfer belt causes the dielectric layer. And the toner may be abnormally charged. That is, a dielectric layer,
Depending on the selection of the material of the transfer belt and the toner, the upper layer toner and the dielectric layer are slid by friction,
The dielectric layer is charged to the same polarity as the charge polarity of the toner, while
By contacting the lower layer toner and the transfer belt,
It is conceivable that the transfer belt is charged to a polarity opposite to the charging polarity of the toner. When the dielectric layer is charged to the same polarity as the charged polarity of the toner, the attraction between the surface of the dielectric layer and the toner in the upper layer is switched to a repulsive force, which may cause a cleaning failure. In addition, when the toner in the lower layer is charged to the polarity opposite to that of the transfer belt, the electrostatic attraction force between the toner and the transfer belt increases, which may also cause a cleaning failure. For this reason, it is desirable to reduce sliding friction due to contact between the cleaning member and the transfer belt as much as possible.

The present invention relates to an improvement of the invention according to the prior application, and a first object of the present invention is to abnormally charge a dielectric layer and toner due to contact between a cleaning member having a dielectric layer and a transfer belt. It is an object of the present invention to provide a transfer device capable of suppressing the transfer of the transfer belt and maintaining good transfer belt cleaning performance by the dielectric layer, and an image forming apparatus provided with the transfer device.

Further, in the transfer device and the image forming apparatus provided with the transfer device according to the above-mentioned prior application, the transfer belt in the direction orthogonal to the moving direction of the surface of the transfer belt as well as the transfer paper transport area on the transfer belt. (Hereinafter, referred to as “the end of the transfer belt”) may be scattered toner or the like. If toner adheres to the end of the transfer belt other than the transfer paper transport area, the back stain of the transfer paper does not occur,
There is a possibility that the hands and clothes of the worker may be stained during jam clearance or maintenance.

Accordingly, a second object is to provide a transfer device capable of preventing contamination of hands, clothes, and the like by toner attached to an end of a transfer belt, and an image forming apparatus provided with the transfer device. It is to be.

[0014]

According to a first aspect of the present invention, there is provided a transfer belt which is supported by a plurality of rotating members and carries and transports a transfer material. A transfer member that cleans the surface of the transfer belt by contacting the transfer member, and transfers a toner image formed on the image carrier to a transfer material on the transfer belt. A body layer, wherein a surface of the cleaning member and a surface of the transfer belt move in the same direction and at a constant speed at a contact portion between the cleaning member and the transfer belt. Things.

In the transfer device according to the first aspect, the contact portion between the cleaning member provided with the dielectric layer and the transfer belt includes:
The sliding friction between the cleaning member and the transfer belt is suppressed by moving the surface of the cleaning member and the surface of the transfer belt in the same direction and at the same speed. This causes abnormal charging of the dielectric layer such that the attraction between the surface of the dielectric layer and the toner in the upper layer on the transfer belt is switched to repulsion, and the attraction between the toner in the lower layer on the transfer belt and the transfer belt. Is suppressed, and the cleaning performance of the transfer belt by the dielectric layer is favorably maintained.

According to a second aspect of the present invention, in the transfer device of the first aspect, a bias applying means for applying a cleaning bias having a polarity opposite to a charging polarity of the toner forming the toner image to the cleaning member is provided. It is a feature.

In the transfer device according to the second aspect, a bias electric field is formed between the cleaning member and the transfer belt by the bias applying means, in the toner toward the cleaning member. Therefore, a cleaning effect by the bias electric field can be obtained in a state where the cleaning performance of the transfer belt by the dielectric layer is well maintained, so that the surface of the transfer belt can be more favorably cleaned.

According to a third aspect of the present invention, in the transfer device of the second aspect, the absolute value of the cleaning bias applied to the cleaning member is 300 to 2500 V.

In the transfer device according to the third aspect, the absolute value of the cleaning bias applied to the cleaning member is determined by:
By setting the voltage to 300 V or more, a sufficient cleaning effect by the electric field is ensured. By setting the absolute value of the cleaning bias to 2500 V or less, the cost of the power supply to be used is not increased.

In order to achieve the second object,
According to a fourth aspect of the present invention, there is provided an image forming apparatus, comprising: a transfer belt supported by a plurality of rotating bodies to carry and transfer a transfer material; and a cleaning member for cleaning the surface of the transfer belt and having a dielectric layer on the surface. In a transfer device for transferring a toner image formed on a carrier to a transfer material on the transfer belt, a cleaning area of the cleaning member is provided at both ends of the transfer belt in a direction orthogonal to a moving direction of the surface of the transfer belt. Wherein at least one end is included.

In the transfer device according to the fourth aspect, the cleaning area of the transfer belt by the cleaning member includes at least one end of both ends of the transfer belt in a direction orthogonal to the moving direction of the surface of the transfer belt. Then, the toner attached to at least one end is cleaned. As a result, when there is a possibility that an operator may touch the transfer belt, for example, during jam clearance or maintenance,
Contamination of hands and clothes can be prevented.

According to a fifth aspect of the present invention, in the transfer device of the fourth aspect, a cleaning member for cleaning the cleaning member is provided, and a cleaning area of the cleaning member by the cleaning member corresponds to the transfer of the cleaning member. A transfer device comprising a portion corresponding to a cleaning area of a belt.

According to the transfer device of the present invention, the toner moved from the surface of the transfer belt to the cleaning member is periodically cleaned by the cleaning member for cleaning the cleaning member. At this time, since the cleaning region of the cleaning member by the cleaning member includes a portion of the cleaning member corresponding to the cleaning region of the transfer belt, the cleaning member can be cleaned over the entire area where the toner has moved to the cleaning member side. .

According to a sixth aspect of the present invention, there is provided an image carrier, toner image forming means for forming a toner image on the image carrier, and transfer for transferring the toner image formed on the image carrier to a transfer material. In the image forming apparatus provided with the apparatus, the transfer device according to claim 1, 2, 3, 4, or 5 is used as the transfer device.

In the image forming apparatus according to the sixth aspect, by using the transfer apparatus according to the first, second, or third aspect as the transfer apparatus, the transfer is performed in a state in which a good cleaning performance can be exerted on the transfer belt. Since the background toner on the image carrier adhered to the belt and the toner scattered at the time of transfer can be cleaned, it is possible to prevent the back surface of the transfer material, transfer failure, and the like due to belt cleaning failure. Further, by using the transfer device of claim 4 or 5, it is possible to prevent the hands and clothes of the worker from being contaminated at the time of jam clearance or maintenance, so that the operability of the worker can be improved.

[0026]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment in which the present invention is applied to an electrophotographic copying machine (hereinafter referred to as a copying machine) as an image forming apparatus will be described below. First, the configuration and operation of the entire copying machine will be described. FIG. 1 is a schematic configuration diagram of the copying machine. In FIG. 1, a photosensitive drum 10 as an image carrier is rotatably mounted, and a charging device 12, an exposure device (not shown), and a toner image forming means for forming a toner image on the photosensitive drum are provided around the photosensitive drum 10. , A developing device 13, a cleaning device 15, a static elimination device (static elimination lamp) 16, and the like. And the photosensitive drum 1
Below 0, a transfer device 20 is provided.

The transfer device 20 includes a transfer belt 21 which is supported by a driving roller 22 and a driven roller 23 as a rotating body and carries and conveys a transfer sheet as a transfer material. The drive roller 22 and the driven roller 23 are conductive rollers made of metal or the like, and are each grounded.
Around the transfer belt 21, a transfer bias roller 30 and a cleaning roller 40 as a cleaning member that contacts the surface of the transfer belt 21 to clean the surface are provided.

The transfer belt 21 is an endless belt made of a rubber member and has a high resistance in which a fluorine-based material is surface-coated, and has a volume resistivity of 10 ¹⁴ Ωcm. Further, the transfer belt 21 rotates in the direction of the arrow in the figure,
By pushing up a push-up lever (not shown), the push-up lever comes into contact with the photosensitive drum 10, and after the transfer is completed, is separated from the photosensitive drum 10 by the push-up lever.

Further, as shown in FIG.
The output current I for transfer is ₁Output constant current
A power supply 31 is connected to the transfer bias roller 3.
0 and the constant current power supply 31
A charge that provides a positive transfer charge with a polarity opposite to the charge polarity.
It constitutes a load applying means. This transfer bias roller 3
A part of the electric charge supplied to the transfer belt 21 from 0
Flows into the roller 22 and the driven roller 23, and the feedback current I
₂And I₃Is returned to the constant current power supply 31. Also feeling
Roll in which the optical drum 10 and the transfer belt 21 face and contact with each other.
Effective in the shooting area, which contributes to the transfer flowing to the photoconductor 10 side
Transfer current I₄Is expressed by the following equation 1 so that
Output current I so that₁Control.

I ₄ = I ₁ −I ₂ −I ₃

In the above configuration, the photosensitive drum 10 is
After the surface is uniformly charged by the charging device 12, a light signal L from the exposure device is irradiated to form an electrostatic latent image. This electrostatic latent image is developed by the developing device 13 to form a toner image as a visible image. In this embodiment, a negatively charged toner using styrene acryl as a base material is used.

Then, a transfer electric field is formed in the transfer area by the transfer bias roller 30, and the photosensitive drum 10
The upper toner image is transferred onto a transfer sheet on the transfer belt 21, and then conveyed to a fixing device (not shown) to be fixed.

On the other hand, the photosensitive drum 10 after the transfer of the toner image
The untransferred toner is removed from the surface by the cleaning device 15, and the residual charge is removed by the charge removing device 16 in preparation for the next charging.

Next, cleaning of the transfer belt 21 will be described. In FIG. 1, the surface of the transfer belt 21 is cleaned by a cleaning roller 40. As shown in FIG. 2, the cleaning roller 40 is obtained by covering an outer periphery of a core metal 41 as a roller base with an elastic layer 42 having a thickness of about 100 μm. In the present embodiment, a tube made of a nylon-based material in which carbon black as a resistance control agent is dispersed is used as the dielectric layer 42, but may be coated with a dielectric material, for example.

In the present embodiment, the cleaning roller 40 is made to bite into the transfer belt 21 by about 1 mm, and the cleaning roller 40 is moved in the direction of the arrow in FIG. The cleaning roller is rotated in such a direction that the surface of the transfer belt 21 and the surface of the transfer belt 21 move in the same direction. The surface of the cleaning roller 40 and the surface of the transfer belt 21 are rotated so as to move at a constant speed.

In this embodiment, a hard roller made of a cored bar 41 is used as the cleaning roller 40, but a soft roller made of, for example, an elastic body is used as the cleaning roller 40. The transfer belt 21 may be configured to face the backing member or the like so as to bite into the transfer belt 21. In addition, regardless of the hard roller and the soft roller, the transfer belt 21 may be configured to be pressed by a backing member provided on the inner peripheral surface side of the belt and contact the cleaning roller 40.

In the above configuration, the cleaning roller 4
When the negatively charged toner on the transfer belt 21 comes in contact with the dielectric layer 42 on the surface of the transfer belt 21, the dielectric layer 42
A polarity opposite to the charged polarity of the toner, that is, a positive charge is induced on the surface portion, and an electrostatic attraction force is generated between the dielectric layer 42 and the toner. At this time, the layered toner sandwiched between the transfer belt 21 and the dielectric layer 42 has an electrostatic attraction force (hereinafter referred to as a dielectric attraction force) between the transfer layer 21 and the dielectric layer, and the toner between the transfer belt and the toner. The electrostatic attraction force (hereinafter referred to as a belt attraction force) acts between the toner particles, but the magnitude of each electrostatic attraction force acting on the toner is inversely proportional to the square of the distance to the toner.
For the toner in the upper part of the surface of the transfer belt 21, the dielectric attraction force is higher than the belt attraction force. Therefore, the toner in the upper layer on the transfer belt 21 moves to the dielectric layer side and is removed from the transfer belt. Also, the dielectric layer 4
Since a charge having a polarity opposite to the charge polarity of the toner is always induced on the two surface portions, the toner whose charge polarity is inverted can also be moved toward the surface of the dielectric layer. The toner that has moved to the surface of the dielectric layer 42 of the cleaning roller 40 is periodically cleaned by a rubber blade 44 as a cleaning member of the cleaning roller 40.

In order to more reliably move the toner to the surface of the dielectric layer 42, in addition to the configuration shown in FIG. 1, a bias application for applying a positive cleaning bias having a polarity opposite to the charging polarity of the toner to the cleaning roller 40 is applied. Means may be provided. FIG. 3 is a configuration example of the transfer device 20 provided with a bias applying unit. A constant voltage power supply 45 as a bias applying means is connected to the core metal 41 of the cleaning roller 40, and a bias of, for example, plus 500 V is applied. Incidentally, in the illustrated example, as a bias applying means, but provided separately the constant-voltage power supply 45 and the constant current source 31 is a charging unit for transferring, the transfer current I ₄ to the photosensitive drum 10 more For accurate control, the constant current power supply 31 may be configured to also serve as a power supply as a bias applying means to the cleaning roller 40.

In the configuration example of FIG. 3, the above-mentioned dielectric attraction force is maintained, and the potential difference between the cleaning roller 40 and the transfer belt 21 by the constant current power supply 31 is
A bias electric field toward the cleaning roller 40 is formed on the toner. Thereby, a part of the toner on the transfer belt 21 moves to the surface of the dielectric layer 42 by the electrostatic force,
Another part moves to the surface of the dielectric layer 42 by the bias electric field. As described above, more toner can be removed by the dielectric attraction force and the electrostatic force due to the bias electric field, and the surface of the transfer belt 21 can be cleaned better. Further, at this time, since the dielectric layer 42 is provided on the surface of the cleaning roller, the cleaning bias is not injected into the toner, and there is no possibility that reverse toner is generated. It has been experimentally confirmed that a cleaning bias applied to the cleaning roller is set to have a polarity opposite to the charging polarity of the toner and an absolute value of 300 V or more to sufficiently obtain a cleaning effect by an electric field. If the cleaning bias is too large, the cost of the power supply to be used increases, so it is appropriate to set the upper limit to about 2500 V.

Incidentally, in order to maintain such good cleaning performance on the transfer belt 21, abnormal charging of the dielectric layer 42 and toner due to contact between the cleaning roller 40 and the transfer belt 21 is prevented. There is a need. That is, the dielectric layer 4 made of a nylon-based material
2. Transfer belt 2 coated with fluorine-based material
In the combination of No. 1 and a toner using styrene acryl as a base material, the toner in the upper layer and the dielectric layer 42 are slid and rubbed, so that the toner is abnormally charged to the same polarity as the toner. It is conceivable that the toner is abnormally charged to a polarity opposite to that of the transfer belt 21 due to the contact with the transfer belt 21. When the dielectric layer 42 is charged to the same polarity as the charged polarity of the toner, the attraction between the surface of the dielectric layer 42 and the toner of the upper layer is switched to a repulsive force, which may cause a cleaning failure. Further, when the toner in the lower layer is charged to the opposite polarity to that of the transfer belt 21, the electrostatic attraction force between the toner and the transfer belt 21 becomes large, and similarly, there is a possibility that cleaning failure may be caused.

Therefore, in the present embodiment, as described above, the surface of the cleaning roller 40 and the transfer belt 21 are brought into contact at the contact portion between the cleaning roller 40 and the transfer belt 21.
The cleaning roller 40 is rotated so that the surface of the cleaning roller 40 moves in the same direction and at a constant speed. As a result, the sliding friction between the cleaning roller 40 and the transfer belt 21 can be suppressed, and abnormal charging of the dielectric layer such that the adsorption force between the surface of the dielectric layer 42 and the upper layer toner is switched to repulsive force, It is possible to suppress abnormal charging of the toner that increases the attraction force between the toner and the transfer belt 21, and to maintain good cleaning performance of the transfer belt 21 by the dielectric layer 42.

Next, the transfer belt 21 in the present embodiment
, Cleaning roller 40 and rubber blade 4
4 will be described with reference to FIGS. 4 and 5. At the time of jam clearance or maintenance, at least one of the two ends of the transfer belt 21 in a direction orthogonal to the direction of movement of the surface of the transfer belt 21 because the hands and clothes of the worker may be contaminated. Need to be cleaned.

Therefore, in the present embodiment, the cleaning area of the transfer belt 21 by the cleaning roller 40 is configured to include both end portions of the transfer belt 21 in the orthogonal direction. The rubber blade 44
Is configured so that the cleaning roller 40 includes a portion corresponding to the cleaning region of the transfer belt 21 of the cleaning roller 40. Specifically, as shown in FIG. 4 and FIG.
The width of the transfer belt 21 in the axial direction is larger than the width of the transfer belt 21 in the orthogonal direction, and the cleaning roller 40 is disposed so as to be able to abut over the entire area of the transfer belt 21 in the width direction. Further, the width of the rubber blade 44 in the axial direction is formed to be larger than the width of the transfer belt 21, and
The rubber blade 44 is disposed so as to be able to abut over the entire contact area of the cleaning roller 40 with the transfer belt 21 in the roller axis direction. Thus, the toner adhered to both ends of the transfer belt 21 is cleaned by the cleaning roller 40, and the toner moved from the surface of the transfer belt 21 to the surface of the cleaning roller 40 is periodically cleaned by the rubber blade 44.

As described above, according to the present embodiment, the transfer belt 2
In contrast, the transfer belt 21 can clean the background toner on the photosensitive drum 10 and the toner scattered at the time of transfer in a state where good cleaning performance can be exhibited. A good image can be formed without causing back-side dirt or transfer failure of the transfer paper due to the cleaning failure. Further, by cleaning the toner adhered to both ends of the transfer belt 21, it is possible to prevent the hands and clothes from being stained by the toner adhered to the both ends, so that the operability of the operator at the time of jam clearance or maintenance is improved. Can be improved. Further, since the toner that has moved from the surface of the transfer belt 21 to the cleaning roller 40 side is periodically cleaned, contamination of the cleaning roller 40 can be prevented, and the cleaning performance of the transfer belt 21 can be stably maintained.

Next, 10,000 copies (A4 landscape) using the copying machine shown in FIG.
The result of evaluating the cleaning performance when copying is performed and cleaning is performed using the cleaning roller 40 will be described. Table 1 below shows the rotation conditions of the cleaning roller 40 and the evaluation results. The cleaning performance is such that the residual toner on the transfer belt 21 after the cleaning is transferred to both sides of the tape with a colorless and transparent adhesive tape.
The optical density (ID) of the toner on the tape measured using a Macbeth densitometer was measured, and the density difference (ΔI) was determined based on the optical density (ID) of the adhesive tape before cleaning.
D) was evaluated. That is, the smaller the ΔID, the higher the cleaning performance. In this evaluation, the configuration shown in FIG. 3 was adopted, and a positive bias of 500 V was applied to the cleaning roller 40.
As the dielectric layer 42, a nylon tube having the following characteristic values was used. Volume resistivity: 2 × 10 ⁹ Ωcm Surface resistivity: 4 × 10 ¹⁰ Ω / □ Relative permittivity: 11 Capacitance: 1000 pF

[0045]

[Table 1]

As shown in Table 1, as a result of the evaluation, the surface of the cleaning roller 40 and the surface of the transfer belt 21 were moved in the same direction and at a constant speed, so that the cleaning performance by the dielectric layer 42 was improved. It was confirmed that it could be maintained.

[0047]

According to the first to third aspects of the present invention, abnormal charging of the dielectric layer and toner due to contact between the cleaning member having the dielectric layer and the transfer belt is suppressed, and the transfer belt is cleaned by the dielectric layer. There is an excellent effect that good performance can be maintained.

In particular, according to the second aspect of the present invention, there is an excellent effect that the transfer belt surface can be more favorably cleaned by adding the cleaning effect by the electric field.

In particular, according to the invention of claim 3, there is an excellent effect that the cleaning effect by the electric field can be sufficiently ensured and the cost of the power supply used can be suppressed.

According to the fourth aspect of the present invention, by cleaning the toner adhered to at least one end of the transfer belt, it is possible to prevent contamination of hands, clothes, and the like due to the toner adhered to the end. There is an excellent effect that the operability of the operator at the time of processing and maintenance can be improved.

In particular, according to the fifth aspect of the present invention, since the toner moved from the surface of the transfer belt to the cleaning member is periodically cleaned, contamination of the cleaning member can be prevented, and the cleaning performance of the transfer belt can be prevented. There is an excellent effect that can be maintained stably.

According to the sixth aspect of the present invention, by using the transfer device of the first, second, or third aspect, it is possible to prevent the back material of the transfer material from being improperly cleaned by the poor cleaning of the transfer belt and to prevent poor transfer. There is an excellent effect that an image can be formed. In addition, by using the transfer device according to claim 4 or 5, since the hands and clothes of the worker are not contaminated at the time of jam clearance or maintenance,
There is an excellent effect that the operability of the worker is improved.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram of a copying machine according to an embodiment.

FIG. 2 is a cross-sectional view of a cleaning roller mounted on the copying machine.

FIG. 3 is a schematic configuration diagram showing another configuration example of the transfer device in the copying machine.

FIG. 4 is an essential part perspective view showing a positional relationship between a cleaning roller and a rubber blade with respect to a transfer belt.

FIG. 5 is an explanatory diagram of a positional relationship between a cleaning roller and a rubber brake with respect to a transfer belt.

[Explanation of symbols]

 REFERENCE SIGNS LIST 10 photoconductor drum 12 charging device 13 developing device 15 cleaning device (for photoconductor drum) 16 static eliminator 20 transfer device 21 transfer belt 22 drive roller 23 driven roller 30 transfer bias roller 31 constant current power supply 40 cleaning roller 41 core metal 42 dielectric Body layer 44 Rubber blade 45 Constant voltage power supply

 ────────────────────────────────────────────────── ─── Continued on the front page (72) Inventor Hiroshi Saito 1-3-6 Nakamagome, Ota-ku, Tokyo F-term in Ricoh Co., Ltd. (reference) 2H032 AA05 BA18 BA23 BA26 BA30

Claims (6)

[Claims] An image bearing member includes a transfer belt supported by a plurality of rotating members and carrying and transferring a transfer material, and a cleaning member that contacts the transfer belt and cleans a surface of the transfer belt. A transfer device that transfers the toner image formed on the transfer belt to a transfer material on the transfer belt, wherein a dielectric layer is provided on the surface of the cleaning member, and a contact portion between the cleaning member and the transfer belt is used to transfer the toner image to the transfer member. The surface and the surface of the transfer belt are in the same direction,
And a transfer device configured to move at a constant speed. 2. The transfer device according to claim 1, further comprising: a bias applying unit that applies a cleaning bias having a polarity opposite to a charging polarity of the toner forming the toner image to the cleaning member. . 3. The transfer device according to claim 2, wherein the absolute value of the cleaning bias applied to the cleaning member is 300 to 2500 V. 4. An image carrier, comprising: a transfer belt supported by a plurality of rotating bodies and carrying and transferring a transfer material; and a cleaning member for cleaning the surface of the transfer belt and having a dielectric layer on the surface. A transfer device for transferring a toner image formed thereon to a transfer material on the transfer belt, wherein a cleaning area of the transfer belt by the cleaning member has both ends of the transfer belt in a direction orthogonal to a moving direction of the surface of the transfer belt. A transfer device comprising at least one end of the sections. 5. The transfer device according to claim 4, further comprising a cleaning member for cleaning the cleaning member, wherein a cleaning area of the cleaning member by the cleaning member is provided in a cleaning area of the transfer belt of the cleaning member. A transfer device comprising a corresponding portion. 6. An image carrier, a toner image forming means for forming a toner image on the image carrier, and a transfer device for transferring the toner image formed on the image carrier to a transfer material. An image forming apparatus, wherein the transfer device according to claim 1, 2, 3, 4, or 5 is used as the transfer device.