JP2008309822A - Cleaning device, and image forming apparatus and process cartridge including device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To inexpensively achieve both of effective removal of untransferred toner by cleaning and inhibition of filming. <P>SOLUTION: A cleaning device 7 provides negative polarity to toner depositing on a surface of a photoreceptor 1 through a polarity control member 75 and removes the toner by cleaning through a brush roller 71 with an applied positive bias, wherein the brush roller comprises conductive raise 71a and insulating raise 71b arranged at positions different from each other in a rotation direction of the brush roller. In the conductive raise, flexure to an upstream side in the rotation direction of the brush roller occurs by bias application, and close touch with the surface of the photoreceptor can be ensured to produce a high electrostatic cleaning effect. In the insulating raise, since such flexure does not occur, the original mechanical rubbing force can be exhibited to bring about a high filming inhibition effect. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a cleaning device that removes unnecessary toner adhering to the surface of an image carrier, and an image forming apparatus and a process cartridge such as a copying machine, a printer, and a facsimile equipped with the cleaning device.

  In an electrophotographic image forming apparatus, in general, unnecessary toner (transfer residual toner) remaining on the surface of an image carrier after the toner image is transferred from the image carrier such as a latent image carrier or an intermediate transfer body. Remove with a cleaning device. As this cleaning device, since it has a simple structure and excellent cleaning performance, a blade-type device that is scraped off by a cleaning blade is widely used. In addition, the blade method has an advantage that the effect of suppressing filming is high because the force for mechanically rubbing the surface of the image carrier is strong. Filming means that additives such as silica and zinc stearate contained in the toner are released from the toner body due to mechanical stress during the image forming process, and adhere to the surface of the image carrier in a thin film form. It is a phenomenon. When this filming occurs, the adhesion force of the toner adhering to the surface of the image carrier is weakened, and problems such as a phenomenon called image flow occur.

  In recent years, there is a tendency to reduce the particle size of toner in order to meet the demand for higher image quality. Further, in order to reduce the cost, the toner tends to be formed into a spherical shape by polymerization. Incidentally, a nearly spherical toner (spherical toner) formed by a polymerization method or the like is also characterized by higher transfer efficiency than a conventional pulverized toner (deformed toner). As a result, it is possible to meet the recent demand for higher image quality and to obtain an effect of reducing the amount of toner discarded as residual transfer toner. When cleaning a toner having a small particle size or a spherical toner by a blade method, it is difficult to completely dam these toners with the cleaning blade, and a phenomenon that a part of the toner slips through the cleaning blade easily occurs. As a result, it is necessary to press the cleaning blade against the surface of the image carrier with a stronger force than in the case of pulverized toner (deformed toner). For this reason, the surface of the cleaning blade and the image carrier is accelerated, and the life of the cleaning blade and the image carrier is shortened. In addition, there is a drawback that the driving load for moving the surface of the image carrier increases. Therefore, as a method for effectively cleaning such a small particle size toner or a spherical toner, an electrostatic cleaning method for cleaning the toner on the surface of the image carrier by electrostatic action has been studied.

  Here, in general, an electrophotographic image forming apparatus applies a bias having a polarity opposite to the polarity (normal polarity) of the toner attached on the surface of the image carrier in the transfer process to remove the toner on the surface of the image carrier. Transfer onto a transfer material such as a recording material. Therefore, in the transfer residual toner remaining on the surface of the image carrier after the transfer, there are normal polarity toners with normal polarity and reversely charged toners charged with a polarity opposite to the normal polarity (FIG. 11). reference). Therefore, when the electrostatic cleaning method is employed, a configuration capable of electrostatically collecting bipolar toner is required.

FIG. 12 is an explanatory diagram for explaining an example of a conventional cleaning apparatus employing an electrostatic cleaning method.
In this cleaning device, a first conductive brush roller 171 to which a positive voltage is applied and a second conductive brush roller 172 to which a negative voltage is applied are moved in the direction of surface movement of the photoreceptor 1 as an image carrier. Are arranged side by side. In this cleaning device, toner that is negatively charged by the first conductive brush roller 171 is cleaned out of the transfer residual toner, and toner that is positively charged by the second conductive brush roller 172 is cleaned. The toner attached to the brush rollers 171 and 172 is removed from the brush rollers 171 and 172 by the removing means 173 and 174, respectively. However, with such a configuration, there is a problem that the cleaning device becomes large. Therefore, Patent Document 1 proposes a cleaning device that can clean toner of both polarities with a single brush roller.

  The cleaning device described in Patent Document 1 includes a first region that applies a positive bias and a second region that applies a negative bias to a plurality of conductive brushes constituting a brush roller. Is provided. Then, by rotating the brush roller, the positive first region and the negative second region are brought into contact with the surface of the image carrier. As a result, of the transfer residual toner, the negatively charged toner is cleaned in the first region, and the positively charged toner is cleaned in the second region. According to this configuration, since the bipolar toner can be cleaned with one brush roller, it is possible to suppress an increase in the size of the cleaning device.

JP 2005-157374 A

However, when a negative or positive voltage is applied to the conductive brush as in the cleaning device described in Patent Document 1, the mechanical rubbing force on the surface of the image carrier is lowered, and filming is sufficiently performed. The problem of being unable to be suppressed occurred. Therefore, the present inventors visually observed the behavior of the raising in the case where the voltage was applied to the raising of the brush roller and the case where the voltage was not applied, and confirmed the following behavior. That is, when a voltage is applied to the raising, the conductive raising that is in contact with the surface of the image carrier is bent to the upstream side in the movement direction of the brush roller surface. The reason why the raised hair is bent when a voltage is applied to the raised hair is not clear, but as a result of applying a voltage to the raised hair, the raised hair is moved by the brush roller under the influence of the electric field between the image carrier and the raised hair. Presumed to be bent in the direction upstream. As a result of bending of the raising, the contact pressure between the surface of the image carrier and the raising is weakened, and the mechanical rubbing force by the brush roller is reduced.
Further, the cleaning device described in Patent Document 1 requires a complicated configuration in which biases having different polarities are applied to a plurality of regions of one brush roller, and there is a problem that cost reduction is difficult.
The above-described problem can occur not only in the cleaning device that cleans the image carrier, but also in a cleaning device that cleans a surface moving member such as a recording material conveying member to which unnecessary toner can adhere.

  The present invention has been made in view of the above problems, and an object of the present invention is to provide a cleaning device that can achieve both effective cleaning of transfer residual toner and suppression of filming at low cost, and An image forming apparatus and a process cartridge provided with the same are provided.

In order to achieve the above object, the invention according to claim 1 is directed to surface control including a polarity control means for aligning the polarity of toner adhering to the surface of the object to be cleaned to a predetermined polarity, and a plurality of raised brushes on the surface. A cleaning member which is disposed so that the plurality of raised hairs are in contact with the surface of the object to be cleaned on the downstream side of the surface of the object to be cleaned with respect to the polarity control unit; Bias applying means for applying a bias having a polarity opposite to the predetermined polarity, and electrostatically adhering the toner on the surface of the object to be cleaned to the raised parts of the cleaning member, whereby the surface of the object to be cleaned In the cleaning device for cleaning the cleaning member, the plurality of raised brushes provided in the cleaning member are different from each other in the surface movement direction of the cleaning member. Those characterized by comprising a conductive brushed and insulating brushed disposed.
According to a second aspect of the present invention, there is provided the cleaning apparatus according to the first aspect, further comprising removing means for removing toner adhering to the raising of the cleaning member from the cleaning member.
Further, the invention according to claim 3 is the cleaning device according to claim 1 or 2, wherein the conductive raising and the insulating raising are provided with a plurality of surfaces of the cleaning member along a surface moving direction of the cleaning member. It is characterized by being alternately arranged in each area obtained by dividing.
According to a fourth aspect of the present invention, in the cleaning device of the first or second aspect, the conductive raising and the insulating raising are arranged so as to be distributed substantially uniformly on the surface of the cleaning member. It is characterized by.
According to a fifth aspect of the present invention, in the cleaning apparatus according to any one of the first to fourth aspects, the surface of the object to be cleaned passes through the region in contact with the cleaning member. The raised hair and the insulating raised hair are each configured to come into contact with the surface of the object to be cleaned at least once.
The invention according to claim 6 is the cleaning apparatus according to any one of claims 1 to 5, characterized in that the insulating raising is higher in rigidity than the conductive raising. is there.
Further, the invention according to claim 7 is the cleaning apparatus according to any one of claims 1 to 6, wherein the conductive raising portion occupies the surface of the cleaning member as compared with the insulating raising portion. It is characterized by the fact that there are many.
The invention according to claim 8 is the cleaning apparatus according to any one of claims 1 to 6, wherein the insulating raised portion occupies the surface of the cleaning member as compared with the conductive raised portion. It is characterized by the fact that there are many.
According to a ninth aspect of the present invention, an image carrier that moves on the surface, a toner image forming unit that forms a toner image on the surface of the image carrier, and unnecessary toner that adheres to the surface of the image carrier are removed. 2. An image forming apparatus, comprising: a cleaning unit, and finally transferring a toner image formed on the surface of the image carrier to a recording material to form an image on the recording material. The cleaning device according to any one of items 1 to 8 is used.
According to a tenth aspect of the present invention, in the image forming apparatus according to the ninth aspect, a photosensitive member having a crosslinked structure in which the binder resin in the structure of the protective layer or the charge transporting portion is used as the image carrier. Is.
According to an eleventh aspect of the present invention, in the image forming apparatus according to the ninth or tenth aspect, at least the image carrier and the cleaning device are integrally supported and detachable from the main body of the image forming apparatus. It has a cartridge.
According to a twelfth aspect of the present invention, at least an image carrier that moves on the surface and a cleaning unit that removes unnecessary toner adhering to the surface of the image carrier are integrally supported, and the main body of the image forming apparatus In the process cartridge which can be attached to and detached from the printer, the cleaning device according to any one of claims 1 to 8 is used as the cleaning means.

In the present invention, before the unnecessary toner on the surface of the object to be cleaned is electrostatically cleaned by the cleaning member, the polarity of the unnecessary toner is adjusted to one polarity (predetermined polarity) by the polarity control means. Therefore, if only a bias having a polarity opposite to the aligned polarity (predetermined polarity) is applied to the cleaning member, it is possible to remove all of the unnecessary toner including toner of both polarities. Therefore, a complicated configuration in which biases having different polarities are applied to a plurality of regions on the cleaning member is unnecessary, and cost reduction is easy.
Moreover, in this invention, the conductive raising and the insulating raising are arrange | positioned in the mutually different position of the surface movement direction in a cleaning member. As described above, the conductive raised brush behaves to bend to the upstream side in the surface movement direction of the cleaning member when a bias is applied. Since this behavior weakens the contact pressure between the raised hair and the surface of the object to be cleaned, the filming suppression effect is lowered. However, since the contact area between the raised hair and the surface of the object to be cleaned is expanded, the contact state between the raised hair and the surface of the object to be cleaned can be made dense, and the electrostatic cleaning effect by the conductive hair raising can be enhanced. On the other hand, even when a bias is applied, the insulating raised hair does not behave as if it bends upstream in the surface movement direction of the cleaning member, as described above. Therefore, the contact pressure between the raised hair and the surface of the object to be cleaned is not weakened, and a sufficient filming suppressing effect can be obtained.

  As described above, according to the present invention, there is an excellent effect that it is possible to achieve both effective cleaning of transfer residual toner and suppression of filming at low cost.

Hereinafter, an embodiment in which the present invention is applied to a printer which is an image forming apparatus will be described.
FIG. 1 is an explanatory diagram showing a schematic configuration of the entire printer according to the present embodiment.
A charging device 2 for uniformly charging the surface of the photosensitive member 1 with a charging roller 2a, and a laser beam L on the surface of the charged photosensitive member 1 An exposure device (not shown) that forms an electrostatic latent image, and a developing device that forms a toner image by attaching toner charged to a predetermined polarity (negative polarity in this embodiment) to the electrostatic latent image on the surface of the photoreceptor 1. 6. Transfer device 5 for transferring the toner image on the photosensitive member 1 to the transfer paper P conveyed from the paper feed cassette 3 by the transfer roller 12a, and cleaning device 7 for removing the transfer residual toner remaining on the photosensitive member 1 after the transfer. A static elimination lamp 8 for removing the residual potential on the photosensitive member 1 is provided.

  Below the transfer device 5, a paper feed cassette 3 that stores a plurality of transfer papers P as recording materials is disposed. The paper feed cassette 3 rotates the paper feed roller 3a pressed against the uppermost transfer paper P at a predetermined timing, and feeds the transfer paper P to the paper feed conveyance path. In the paper feed conveyance path, the transferred transfer paper P passes through the plurality of conveyance roller pairs 13 and then is sandwiched between the rollers of the registration roller pair 14 and stopped. The registration roller pair 14 faces the transfer nip between the transfer roller 12a and the photoconductor 1 at a timing at which the sandwiched transfer paper P can be superimposed on the toner image formed on the photoconductor 1 as described above. Send it out. As a result, the toner image on the photosensitive member 1 and the transfer paper P sent out by the registration roller pair 14 are brought into close contact with each other at the transfer nip. The toner image on the photoreceptor 1 is electrostatically transferred onto the transfer paper P under the action of a transfer bias.

  A paper transport belt 12 is wound around the transfer roller 12a. The paper conveying belt 12 is stretched between a transfer roller 12a and a driving roller 12b, and moves endlessly counterclockwise in the drawing. A fixing device 9 and a paper discharge roller pair 10 are provided on the left side of the paper conveying belt 12 in the drawing. The transfer paper P on which the toner image is electrostatically transferred is sent to the fixing device 9 by the paper transport belt 12. The transfer paper P that has entered the fixing device 9 is subjected to heat treatment and pressure treatment. As a result, the toner melts while receiving pressure, and the toner image is fixed on the transfer paper P. Then, the transfer paper P is discharged out of the apparatus from the fixing device 9 through the paper discharge roller pair 10.

  Untransferred toner remaining on the photoreceptor without being transferred is collected by the cleaning device 7. The surface of the photoreceptor 1 from which the transfer residual toner has been removed is initialized by the charge eliminating lamp 8 and used for the next image forming process. Unnecessary toner that has been transferred onto the paper transport belt 12 is removed from the paper transport belt 12 by the belt cleaning device 15.

  In this embodiment, the photosensitive member 1, the developing device 6, the charging device 2, and the cleaning device 7 are accommodated in a process cartridge 100 that is a structure that integrally supports them. The process cartridge 100 is detachable from the printer body. Therefore, when the life of a component housed in the process cartridge 100 is reached or maintenance is required, the process cartridge 100 may be replaced, which improves convenience.

FIG. 2 is an explanatory diagram showing a schematic configuration of the cleaning device 7.
The cleaning device 7 includes a brush roller 71 serving as a cleaning member in which countless raised hairs 71a and 71b are planted on the surface of a roller-shaped core member 71c, which is a rotating shaft, and a removing means including a collection roller 72 and a scraper member 73. And a conveying means 74, a polarity control member 75 constituting a polarity control means, and a power source 706. The brush roller 71 is rotated clockwise in the figure by a driving means (not shown) so that the brushed tip is brought into contact with the photoconductor 1 and moved in the direction opposite to the surface of the photoconductor at the contact portion. The transfer residual toner is captured by a plurality of raised brushes that rub against the surface of the photoreceptor. The collection roller 72 is disposed so as to sandwich the brush roller 71 between itself and the photosensitive member 1, and moves in a direction opposite to the surface movement direction of the brush roller at a contact portion with the brush roller 71. It is rotated in the clockwise direction in the figure by driving means (not shown). The plate-shaped scraper member 73 has its leading edge abutted against the collection roller 72 with a predetermined pressure. Further, the conveying means 74 is disposed below the scraper member 73 in the direction of gravity.

  In addition, the polarity control member 75 receives a bias from the power supply 706 to inject charges into the transfer residual toner on the surface of the photosensitive member, and aligns the polarity of the transfer residual toner with the same polarity as the bias polarity received from the power supply 706. . Here, the normal charging polarity of the toner in the present embodiment is negative, but as a result of the action of a positive bias in the transfer nip, some of the toner is positively charged. Therefore, as shown in FIG. 3A, the charge distribution of the transfer residual toner is in a state where the negative polarity toner and the positive polarity toner are mixed. In the present embodiment, the polarity of the bias supplied from the power source 706 is negative. Therefore, the transfer residual toner in a state where the negative polarity toner and the positive polarity toner are mixed is negatively charged by the polarity control member 75, so that the polarity is uniform as shown in FIG. To the negative polarity.

In the present embodiment, the polarity control member 75 is composed of a conductive blade. However, any member that injects electric charges in contact with the transfer residual toner on the surface of the photoreceptor 1 may be a brush-like member. It may also be a film.
Further, in the present embodiment, the configuration in which the polarity is made uniform by injecting the charge upon contact with the transfer residual toner on the surface of the photosensitive member 1 has been described. It may be a means. However, the charge injection method as in the present embodiment is preferable because discharge products that adversely affect image formation are less likely to occur.
Further, in this embodiment, the case where the polarity of the untransferred toner is made to have a negative polarity by the polarity control member 75 is taken as an example, but the same applies even if the polarity is made to have a positive polarity.

A power source 701 is connected to the brush roller 71, and a positive bias is applied thereto. Therefore, the transfer residual toner that is made negative by the polarity control member 75 is electrostatically attracted to the brush roller 71 to which the positive polarity is applied. As a result, the transfer residual toner is removed from the surface of the photoreceptor 1.
Further, a power source 702 is connected to the collection roller 72, and a positive bias is applied. The negative toner electrostatically attracted to the brush roller 71 is collected by the collection roller 72 due to a potential gradient between the brush roller 71 and the collection roller 72. The toner collected on the collection roller 72 is scraped off from the surface of the collection roller 72 by the scraper member 73. The toner scraped off is transported by a transport means 74 to a waste toner bottle (not shown). The toner may be transported to the developing device 6 for reuse.

Next, the configuration of the brush roller 71 will be described.
FIG. 4 is an explanatory view schematically showing the brush roller 71.
As for the brush roller 71 in this embodiment, the conductive brush area | region A and the insulating brush area | region B are alternately arrange | positioned along the surface moving direction of the brush roller 71. FIG.
Examples of the material of the conductive raised portions 71a constituting the conductive brush region A include those obtained by imparting conductivity to a fiber material such as nylon, acrylic, polyester, and PET. The conductivity imparting method may be a core-sheath structure in which a conductive material such as carbon fiber is incorporated as a core in the fiber material described above, or a structure in which a conductive material such as carbon chip is dispersed and mixed in the fiber material. The method may be used. The important point here is that the conductive material such as carbon is not directly in contact with the toner. When the conductive material comes into direct contact with the toner, charge is injected into the toner through the conductive material due to the bias applied to the brush roller 71, and the toner is charged positively and may not be collected by the brush roller 71. It is. Therefore, it is desirable that the conductive material in the brush roller 71 is configured to be covered with an insulating material. The volume resistivity of the conductive raised portions 71a constituting the conductive brush region A is preferably in the range of 10 ⁶ [Ω · cm] to 10 ⁹ [Ω · cm].

  When a positive bias is applied from the power source 701 to the core member 71c of the brush roller 71, a positive bias is applied to the conductive brushed 71a in the conductive brush region A planted on the surface thereof. As a result, as shown in FIG. 4, the transfer residual toner that has been made negative in polarity by the polarity control member 75 is electrostatically adsorbed to the conductive brushing 71 a in the conductive brush region A and removed from the surface of the photoreceptor 1. The At this time, as described above, the conductive raising 71a in the conductive brush region A behaves to bend to the upstream side of the surface movement direction of the brush roller 71 by applying a bias from the power source 701. This behavior results in lowering the filming suppression effect, but since the contact state between the raised 71a and the surface of the photoconductor can be made dense, an effect of increasing the electrostatic cleaning effect can be obtained. Therefore, the transfer residual toner arranged in the negative polarity can be efficiently collected from the surface of the photoreceptor 1 by the conductive raising 71a in the conductive brush region A.

On the other hand, even if a bias is applied, the insulating raising 71b that constitutes the insulating brush region B does not bend toward the upstream side of the surface movement direction of the brush roller 71. Therefore, the contact pressure between the raised bristles 71b and the surface of the photoreceptor is not weakened, and the filming suppressing effect inherent to the insulating raised bristles 71b can be sufficiently exhibited. In addition, the volume resistivity of the insulating raising 71b is made of a high resistance (insulator) of 10 ¹⁶ [Ω · cm] or more.

  Here, in order to more effectively obtain the high cleaning effect by the conductive raising 71a of the conductive brush area A and the filming suppression effect by the insulating raising 71b of the insulating brush area B, the conductive brush area A can be obtained more effectively. It is preferable to lower the rigidity of the conductive raising 71a and to increase the rigidity of the insulating raising 71b in the insulating brush region B. Therefore, it is preferable to use nylon or polyethylene having a low Young's modulus as the material of the conductive raised portions 71a in the conductive brush region A. Moreover, as a material of the insulating raising 71b of the insulating brush region B, it is preferable to use polyester, acrylic, PET or the like having a large Young's modulus. In addition, as a method for increasing the rigidity of the raised hair made of the same material, there is a method of changing the thickness of the raised hair itself.

  As shown in FIG. 4, the relationship between the voltage Vb applied to the collection roller 72 and the voltage Vc applied to the brush roller 71 is Vb <Vc, and the potential gradient is attached to the brush roller 71. The transfer residual toner is electrostatically transferred to the collection roller 72. The voltage Vb at this time is preferably in the range of 200 [V] to 600 [V], and the voltage Vc is preferably in the range of 300 [V] to 800 [V]. In addition, it has been confirmed that the potential difference (Vc−Vb) is in a range of 100 [V] to 500 [V]. That is, if this potential difference is too small, the force for removing the transfer residual toner from the brush roller 71 is so small that it cannot be peeled off. On the other hand, if the potential difference is too large, charge is injected into the transfer residual toner on the brush roller 71, and the transfer residual toner has the same polarity as the polarity of the voltage Vc and cannot be collected from the brush roller 71.

Next, the operation of the cleaning device 7 will be described in detail.
When a print signal is input and an image forming operation is started, after the charging, writing, developing, and transferring steps, the transfer residual toner on the photosensitive member 1 is sent to a portion of the cleaning device 7 facing the brush roller 71. Come. The untransferred toner contains reversely charged toner and uncharged toner that are charged with a polarity opposite to the normal polarity (negative polarity) due to the electric field effect in the transfer process, but reaches the portion facing the brush roller 71. Before the adjustment, the polarity control member 75 makes the negative polarity. When the surface of the photoreceptor 1 enters the tip position P of the nip region 26, it contacts one of the conductive brush region A and the insulating brush region B of the brush roller 71. For example, when the surface of the photoreceptor 1 comes into contact with the conductive brush area A at the tip position P of the nip area 26, the transfer residual toner on the surface of the photoreceptor is electrostatically applied to the conductive brushed 71 a in the conductive brush area A of the brush roller 71. And are removed from the photoreceptor. Then, when the surface of the photosensitive member 1 advances in the nip region, it comes into contact with the insulating brush region B of the brush roller 71 this time. As a result, the toner external additive and the like adhering in the form of a film to the surface of the photosensitive member is mechanically scraped and removed by the insulating brush 71b in the insulating brush region B. Further, the weakly charged toner and the non-charged toner on the surface of the photosensitive member are also mechanically removed from the surface of the photosensitive member by the insulating raised portions 71 b in the insulating brush region B of the brush roller 71. As described above, since the surface of the photosensitive member comes into contact with the regions A and B of the brush roller 71 at least once while passing through the nip region 26, the transfer residual toner on the surface of the photosensitive member is electrostatic or mechanical. The toner additive attached to the surface of the photoreceptor in the form of a film is also removed.

  Transfer residual toner adhering to the conductive raised portions 71 a in the conductive brush region A of the brush roller 71 is electrostatically attracted to the collection roller 72 and removed from the brush roller 71. The transfer residual toner adhering to the recovery roller 72 is blocked by the scraper member 73, and the transfer residual toner separated from the recovery roller 72 falls to the conveying means 74. Transfer residual toner or the like that has dropped onto the conveying means 74 is appropriately discharged out of the cleaning device 7 by the conveying means 74.

  In the present embodiment, the area of the brush roller 71 is divided into eight as shown in FIG. 4, but the number of divisions is not limited to this. However, if the number of divisions is small, in order to bring the conductive brush region A and the insulating brush region B of the brush roller 71 into contact with the surface of the photosensitive member while the surface of the photosensitive member passes through the nip region, It is necessary to increase the rotation speed. More specifically, in the case of a two-divided brush roller, the conductive brush region A and the insulating brush region are formed on the surface of the photosensitive member unless at least one rotation of the brush roller is performed while the surface of the photosensitive member passes through the nip region. Both B cannot be contacted. On the other hand, in the case of an eight-divided brush roller, if the brush roller 71 is rotated 1/4 while the photosensitive member surface passes through the nip region, the conductive brush region A and the insulating brush region B are formed on the photosensitive member surface. Both can be contacted. As described above, the rotation speed of the brush roller 71 can be decreased when the number of divisions of the brush roller 71 is larger. In practice, it is desirable to have four or more divisions.

  As a manufacturing method of the brush roller 71, as shown in FIG. 5, first, the conductive brush region A is formed by electrostatically flocking the conductive yarn cut into a length of 5 mm by applying an adhesive on the substrate. The conductive brush module 76a is manufactured. Moreover, the insulating brush module 76b used as the insulating brush area | region B is manufactured by electrostatically implanting the insulating thread cut and trimmed similarly to a conductive thread on a board | substrate. And these modules 76a and 76b are each joined to the predetermined position on the surrounding surface of the metal core which is the core member 71c. Thereby, the brush roller 71 in which the conductive brush regions A and the insulating brush regions B are alternately arranged along the surface movement direction of the brush roller 71 can be manufactured. The bonding agent used for manufacturing the conductive brush module 76a is desirably conductive, but the bonding agent used for manufacturing the insulating brush module 76b may be either conductive or insulating.

  Moreover, as a method of manufacturing the brush roller 71 without using the above-described brush module, there is a method as shown in FIG. That is, a bonding agent is applied in advance to a region to be the conductive brush region A on the peripheral surface of the cored bar constituting the core member 71c, and the conductive yarn cut and aligned in the region is electrostatically implanted. Similarly, a bonding agent is applied in advance to a region to be the insulating brush region B on the peripheral surface of the metal core, and the insulating yarn cut and aligned in the region is electrostatically flocked. According to this manufacturing method, the substrate of the brush module becomes unnecessary. Note that the bonding agent is desirably conductive for the conductive brush region A, but the bonding agent used for the insulating brush region B may be either conductive or insulating.

  In the present embodiment, the conductive brushed 71a and the insulating brushed 71b are alternately arranged in each region obtained by dividing the surface of the brush roller 71 into a plurality along the brush roller surface moving direction. However, as shown in FIG. 7, conductive brushed 71a and insulating brushed 71b may be mixed and distributed substantially uniformly over the entire surface of the brush roller 71. In this case, the same effect as that of the present embodiment can be obtained. In addition, the brush roller 71 can be manufactured by applying a bonding agent in advance to the surface of the core bar constituting the core member 71c and then electrostatically flocking the mixed yarn in which the conductive yarn and the insulating yarn are mixed. The process can be simplified.

Next, the relationship between the number of divisions of the brush roller 71 and the cleaning property was examined. The result is shown in FIG.
The horizontal axis in FIG. 8 is the voltage value applied to the brush roller 71, and the vertical axis is the ID value indicating the cleaning property. The ID value indicating the cleaning property is a value obtained as follows. The toner on the surface of the photoconductor after passing through the brush roller 71 is transferred to a tape and attached to paper, and the reflection density is measured with a spectrocolorimeter (X-light manufactured by Amtec Corporation). On the other hand, the reflection density is measured with a spectrocolorimeter after attaching only the tape to the paper, and the value obtained by subtracting the reflection density of only the tape from the reflection density of the tape on which the toner on the photoconductor adheres is an ID value indicating cleaning properties. It was. There is a correlation between the ID value and the number of toners, and the ID value increases as the number of toners increases. Therefore, the cleaning property can be determined by the ID value.

Specific conditions of the image forming apparatus at the time of this investigation are as follows.
Photoconductor diameter: φ40 [mm]
Photoconductor linear velocity: 100 [mm / s]
Brush roller diameter: φ30 [mm]
Brush roller linear velocity: 300 [mm / s]
Brush bite amount: 1 [mm]
Toner: Spherical φ5 [μm]
Applied voltage of brush roller 71: +200 [V]

As shown in FIG. 8, it can be seen that the cleaning property is improved as the number of divisions of the brush roller region is increased. This is presumably because the number of contact between the surface of the photosensitive member and each of the areas A and B increases as the number of divided areas of the brush roller increases. More specifically, in the case of a brush roller with four divided areas, the conductive brush area A is in contact with the surface of the photosensitive member only twice during one rotation of the brush roller, but the brush is divided into eight areas. The roller contacts 4 times during one rotation. The brush roller whose area is divided into 12 allows the conductive brush area A to come into contact with the surface of the photosensitive member 6 times during one rotation. Thus, it is considered that increasing the number of divisions of the region increases the number of contact times of the region and improves the cleaning performance. Although filming could not be quantitatively evaluated, visual rank evaluation did not provide a sufficient correlation between the number of divisions and filming.
Further, as can be seen from FIG. 8, the cleaning performance improves as the voltage applied to the brush roller 71 increases.

  In the present embodiment, the ratio of the areas A and B of the brush roller 71 occupying the surface of the brush roller 71 is substantially equal, but the ratio is appropriately changed in accordance with the characteristics of the printer and the characteristics of the toner. May be. For example, although an actual product has good cleaning properties, a low-melting-point toner is sometimes used to achieve low-temperature fixing. In such a case, the resin component and the external additive are likely to adhere to the photoreceptor and filming is likely. In such a case, as shown in FIG. 9A, it is desirable to increase the filming suppression effect by increasing the ratio of the insulating brush region B to that of the conductive brush region A. On the other hand, a product intended to increase the image resolution may use a small particle size toner, and thus the cleaning performance may be reduced. In such a case, as shown in FIG. 9B, the ratio of the conductive brush region A may be made larger than that of the insulating brush region B to enhance the electrostatic cleaning effect. In the case of the brush roller 71 obtained by flocking the mixed yarn as shown in FIG. 7, the same adjustment can be performed by appropriately changing the blending ratio of the conductive yarn and the insulating yarn.

Next, the photoreceptor 1 that is preferably used in the printer of this embodiment will be described.
The basic structure of the photoreceptor is composed of a conductive support, a latent image carrying layer, and a surface layer (protective layer). Further, the latent image bearing layer needs to be electrically insulating so that it can be charged, but a non-photoconductive dielectric layer or a photoconductive photosensitive layer can be used.

  The contact pressure between the photosensitive member 1 and the brush roller 71 of the cleaning device 7 is significantly smaller than that of the conventional blade method. However, when the brush roller 71 is rotated at a high speed, the surface of the photosensitive member is worn over time. Therefore, in order to ensure a long life, the durability can be improved by making the binder resin of the photoconductor protective layer into a crosslinked structure, or by strengthening it by having a charge transport site in the structure of the binder resin having a crosslinked structure. . Concerning the formation of the crosslinked structure of the binder resin, a reactive monomer having a plurality of crosslinkable functional groups in one molecule is used to cause a crosslinking reaction using light or thermal energy to form a three-dimensional network structure. To do. This network structure functions as a binder resin and exhibits high wear resistance. From the viewpoint of electrical stability, printing durability, and life, it is a very effective means to use a monomer having a charge transporting ability in whole or in part as the reactive monomer. By using such a monomer, a charge transporting site is formed in the network structure, and the function as a protective layer can be sufficiently expressed. The reactive monomer having charge transporting ability includes a compound containing at least one charge transporting component and a silicon atom having a hydrolyzable substituent in the same molecule, and a charge transporting component in the same molecule. A compound containing a hydroxyl group, a compound containing a charge transporting component and a carboxyl group in the same molecule, a compound containing a charge transporting component and an epoxy group in the same molecule, a charge transporting component in the same molecule And a compound containing an isocyanate group. These charge transport materials having a reactive group may be used alone or in combination of two or more. More preferably, a reactive monomer having a triarylamine structure is effectively used as the monomer having a charge transporting ability because of high electrical and chemical stability and high carrier mobility. In addition to this, monofunctional and bifunctional polymerizable monomers and polymerizable oligomers are used in combination for the purpose of imparting functions such as viscosity adjustment during coating, stress relaxation of the cross-linked charge transport layer, low surface energy and friction coefficient reduction. be able to. As these polymerizable monomers and oligomers, known ones can be used.

  In addition, the hole transporting compound is polymerized or cross-linked using heat or light, but when the polymerization reaction is performed by heat, the polymerization reaction proceeds only with thermal energy or a polymerization initiator is required. However, in order to advance the reaction efficiently at a lower temperature, it is preferable to add an initiator. In the case of polymerization by light, it is preferable to use ultraviolet light as light, but the reaction rarely proceeds only by light energy, and a photopolymerization initiator is generally used in combination. The polymerization initiator in this case mainly absorbs ultraviolet rays having a wavelength of 400 [nm] or less, generates active species such as radicals and ions, and initiates polymerization. In the present invention, the above-described heat and photopolymerization initiator can be used in combination.

  The charge transport layer having a network structure formed in this manner has high wear resistance, but has a large volume shrinkage during the crosslinking reaction, and if it is too thick, it may cause cracks. In such a case, the protective layer may be a laminated structure, a low molecular dispersion polymer protective layer may be used for the lower layer (photosensitive layer side), and a protective layer having a crosslinked structure may be formed on the upper layer (surface side). good.

Specific examples of the photoreceptor 1 include those in which the protective layer coating solution, film thickness, and preparation conditions are as follows. That is, 182 parts of methyltrimethoxysilane, 40 parts of dihydroxymethyltriphenylamine, 225 parts of 2-propanol, 106 parts of 2% acetic acid, and 1 part of aluminum trisacetylacetonate were prepared to prepare a coating solution for the protective layer, This coating solution is applied and dried on the charge transport layer, and heat-cured at 110 ° C. for 1 hour to form a protective layer having a thickness of 3 μm. Further, 30 parts of the hole transporting compound represented by the structural formula (I) shown in the chemical formula 1 below, an acrylic monomer of the structural formula (II) shown in the chemical formula 2 below and a photopolymerization initiator (1-hydroxy-cyclohexyl-phenyl) -Ketone) is dissolved in a mixed solvent of 50 parts of monochlorobenzene and 50 parts of dichloromethane to prepare a coating material for the surface protective layer, and this coating material is applied onto the above charge transport layer by a spray coating method. Then, a surface protective layer having a film thickness of 5 [μm] is formed by curing for 30 seconds with a light intensity of 500 [mW / cm ² ] using a metal halide lamp.

  In this embodiment, the example in which the drum-shaped photosensitive member 1 is used as the image carrier has been described. However, the present invention can be applied to an image carrier having another shape. For example, the present invention can be similarly applied to an apparatus using a belt-like photoreceptor that is stretched between two rollers and moves endlessly. In addition, the case where the charging potential of the photosensitive member 1 is negative and the developing device adopting the reversal developing method using the two-component developer is provided has been described. However, in the present invention, the charging potential of the photosensitive member is negative. The present invention is not limited to those having a positive polarity, and can be similarly applied to those having a positive charge potential. Further, the present invention can be similarly applied to one using a one-component developer or one using a regular development system.

  In this embodiment, the cleaning device of the present invention is applied to a monochrome image forming apparatus having one process cartridge, but the present invention is not limited to this. For example, the present invention can be applied to a color image forming apparatus in which four process cartridges 100Y, 100C, 100M, and 100K of magenta, cyan, yellow, and black are arranged side by side as shown in FIG.

  Further, the present invention can be applied to an intermediate transfer type image forming apparatus that transfers a toner image on a photosensitive member to an intermediate transfer member and transfers the toner image on the intermediate transfer member to a transfer sheet. At this time, the cleaning device of the present invention can be applied not only as a cleaning device for cleaning the transfer residual toner attached on the photosensitive member but also as an intermediate transfer member cleaning device for cleaning the transfer residual toner attached on the intermediate transfer belt. . As the intermediate transfer member, in addition to a belt-shaped intermediate transfer belt, a drum-shaped intermediate transfer drum or the like can be used. The electrical characteristics (volume resistivity, surface resistivity, etc.), thickness, structure (single layer, double layer, multiple layers), material, material, etc. of the intermediate transfer member are appropriate depending on the imaging conditions. Can be selected and employed.

As described above, the printer cleaning device 7 according to the present embodiment controls the polarity of the toner that adheres to the surface of the photosensitive member 1 that is the image carrier as the surface-moving member to be cleaned to a predetermined polarity (negative polarity). A polarity control member 75 and a power source 706 as means, and a surface moving member provided with a plurality of raised hairs on the surface. A brush roller 71 serving as a cleaning member disposed so as to be in contact therewith, and a power source 701 serving as a bias applying unit that applies a bias having a polarity opposite to the predetermined polarity (positive polarity) to the brush roller 71. The cleaning device cleans the surface of the photoreceptor 1 by electrostatically adhering the toner on the surface of the surface of the brush roller 71 to the brushed brush. The plurality of raised brushes included in the brush roller 71 are composed of conductive raised brushes 71 a and insulating raised brushes 71 b arranged at different positions in the surface movement direction of the brush roller 71. As a result, in the conductive brush region A composed of the conductive raised portions 71a, the bias is applied, so that it bends to the upstream side in the movement direction of the brush roller surface. Electric cleaning effect is high. On the other hand, in the insulating brush region B constituted by the insulating raised portions 71b, since it does not bend even when a bias is applied, the original mechanical rubbing force can be exhibited and the effect of suppressing filming is high. As described above, in this embodiment, both the high electrostatic cleaning effect and the high filming suppression effect can be obtained by the single brush roller 71.
In the present embodiment, a collection roller 72 and a power source 702 are provided as a removing unit that removes toner adhering to the raised portions 71 a of the brush roller 71 from the brush roller 71. Thereby, the electrostatic cleaning effect of the brush roller 71 can be maintained for a long time.
Moreover, in this embodiment, the conductive raising 71a and the insulating raising 71b are alternately arrange | positioned in each area | region obtained by dividing | segmenting the surface of the brush roller 71 into multiple along the brush roller surface moving direction. . Thereby, both the high electrostatic cleaning effect and the high filming suppression effect can be obtained efficiently.
In addition, you may arrange | position the electroconductive raising 71a and the insulating raising 71b so that it may distribute on the surface of the brush roller 71 substantially uniformly. In this case, the manufacturing process of the brush roller 71 can be simplified, and the cost of the brush roller 71 can be reduced.
Further, in the present embodiment, while the surface of the photoconductor 1 passes through the region in contact with the brush roller 71, the conductive napping 71a and the insulating napping 71b each contact with the photoconductor surface at least once. It is configured as follows. Thus, the transfer residual toner can be removed and filming can be suppressed by passing the photosensitive member surface once through the portion facing the brush roller 71.
Moreover, in this embodiment, since the insulating raising 71b has higher rigidity than the conductive raising 71a, both the electrostatic cleaning effect and the filming suppression effect can be enhanced at the same time.
Further, if the proportion of the conductive raising 71a occupying the surface of the brush roller 71 is larger than that of the insulating raising 71b, a cleaning device having an excellent electrostatic cleaning effect can be provided.
On the contrary, if the ratio of the insulating raising 71b occupying the surface of the brush roller 71 is larger than that of the conductive raising 71a, it is possible to provide a cleaning device having an excellent filming suppression effect.

1 is an explanatory diagram illustrating a schematic configuration of an entire printer according to an embodiment. FIG. It is explanatory drawing which shows schematic structure of the cleaning apparatus provided in the printer. (A) is a graph which shows the charge distribution of the transfer residual toner before passing through the opposing part of the polarity control member of the cleaning device. (B) is a graph showing the charge distribution of the untransferred toner after passing through the facing portion of the same polarity control member. It is explanatory drawing which showed the brush roller of the cleaning apparatus typically. It is explanatory drawing for demonstrating an example of the manufacturing method of the same brush roller. It is explanatory drawing for demonstrating the other example of the manufacturing method of the same brush roller. It is explanatory drawing for demonstrating the further another example of the manufacturing method of the same brush roller. It is a graph which shows the investigation result about the relationship between the area | region division number of the same brush roller, and cleaning property. (A) is the schematic diagram of the brush roller which made the ratio of the insulating brush area | region B larger than the electroconductive brush area | region A. FIG. (B) is a schematic diagram of a brush roller in which the proportion of the conductive brush region A is larger than that of the insulating brush region B. 1 is a schematic configuration diagram of a tandem color image forming apparatus. FIG. 4 is a diagram illustrating a charge distribution of a transfer residual toner on a photoconductor. It is a principal part block diagram of the conventional cleaning apparatus.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Photoconductor 7 Cleaning apparatus 71,171,172 Brush roller 71a Conductive raising 71b Insulating raising 71c Core member 72 Collection roller 73 Scraper member 74 Conveying means 75 Polarity control member 76a Conductive brush module 76b Insulating brush module 100 Process cartridge 173, 174 Removing means 701, 702, 706 Power source A Conductive brush area B Insulating brush area

Claims (12)

Polarity control means for aligning the polarity of the toner adhering to the surface of the object to be cleaned that moves on the surface with a predetermined polarity;
A surface moving member having a plurality of raised portions on a surface thereof, wherein the plurality of raised portions contact the surface of the object to be cleaned on the downstream side of the surface of the object to be cleaned with respect to the polarity control means. A cleaning member to be
Bias application means for applying a bias having a polarity opposite to the predetermined polarity to the cleaning member;
In a cleaning device that electrostatically attaches toner on the surface of the object to be cleaned to the raising of the cleaning member to clean the surface of the object to be cleaned,
The cleaning apparatus, wherein the plurality of raised hairs provided in the cleaning member are composed of conductive raised hairs and insulating raised hairs arranged at different positions in the surface movement direction of the cleaning member. The cleaning device according to claim 1.
A cleaning device comprising a removing means for removing toner adhering to the raising of the cleaning member from the cleaning member. The cleaning device according to claim 1 or 2,
The conductive raising and the insulating raising are alternately arranged in each region obtained by dividing the surface of the cleaning member into a plurality along the surface movement direction of the cleaning member. Cleaning device. The cleaning device according to claim 1 or 2,
The cleaning apparatus, wherein the conductive raising and the insulating raising are arranged so as to be distributed substantially uniformly on the surface of the cleaning member. The cleaning device according to any one of claims 1 to 4,
While the surface of the object to be cleaned passes through the region in contact with the cleaning member, each of the conductive napping and the insulating napping is configured to come into contact with the surface of the object to be cleaned at least once. A cleaning device. The cleaning device according to any one of claims 1 to 5,
The cleaning apparatus according to claim 1, wherein the insulating raising is higher in rigidity than the conductive raising. The cleaning device according to any one of claims 1 to 6,
The cleaning apparatus according to claim 1, wherein the conductive brush has a larger proportion of the surface of the cleaning member than the insulating brush. The cleaning device according to any one of claims 1 to 6,
The cleaning apparatus according to claim 1, wherein the insulating brush has a larger proportion of the surface of the cleaning member than the conductive brush. An image carrier that moves on the surface; a toner image forming unit that forms a toner image on the surface of the image carrier; and a cleaning unit that removes unnecessary toner adhering to the surface of the image carrier. In an image forming apparatus for finally transferring a toner image formed on the surface of a body to a recording material and forming an image on the recording material,
An image forming apparatus using the cleaning device according to claim 1 as the cleaning unit. The image forming apparatus according to claim 9.
An image forming apparatus comprising: a photosensitive member having a crosslinked structure as a binder resin in the structure of a protective layer or a charge transporting portion. The image forming apparatus according to claim 9 or 10,
An image forming apparatus comprising: a process cartridge that integrally supports at least the image carrier and the cleaning device and is detachable from the main body of the image forming apparatus. In a process cartridge that integrally supports at least an image carrier that moves on the surface and a cleaning unit that removes unnecessary toner adhering to the surface of the image carrier and is detachable from the main body of the image forming apparatus ,
9. A process cartridge using the cleaning device according to claim 1 as the cleaning means.

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