JPH09230769A - Image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent permanent deformation of a cleaning member and firm sticking of toner to the cleaning member and an image carrier by means of a simple structure, in an image forming device which recovers and sticks residual transfer toner again between the cleaning member and image carrier. SOLUTION: The main body 12A of the cleaning member 12 is in the form of a sector, and is brought into contact with the photoreceptor 1 at the time of the operation of recovering residual transfer toner on the photoreceptor 1 and the operation of resticking the recovered toner to the photoreceptor 1. When the recovering operation and resticking operation are not carried out, the cleaning member 12 is rotated to be separated from the phtotoreceptor 1.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention forms an electrostatic latent image on a rotationally driven image carrier by means of latent image forming means,
The electrostatic latent image is visualized as a toner image by a developing device, the toner image on the image carrier is transferred to a recording medium by a transfer device, and transfer residual toner on the image carrier after the toner image transfer is removed. The present invention relates to an image forming apparatus that collects by a cleaning member and cleans the surface of the image carrier.

[0002]

2. Description of the Related Art In an image forming apparatus of the above type configured as a copying machine, a printer, a facsimile, or a complex machine thereof, an image carrier is repeatedly used, and therefore, the surface of the image carrier after the toner image is transferred. It is necessary to clean the surface of the image bearing member by removing and collecting the residual toner remaining on the image carrier by a cleaning member. Therefore, conventionally, various cleaning devices for cleaning the image carrier have been proposed and put into practical use, but the conventional cleaning device generally stores the toner collected from the image carrier in a waste toner tank or the like, It is configured to discard this.

By the way, in recent years, in an image forming apparatus of this type which employs an electrophotographic process, it is possible to further reduce the cost and further reduce the amount of toner to be discarded as part of measures against environmental problems. Is requested.

In view of such a point, if the transfer rate of the toner image from the image carrier to the recording medium is set to 100% to eliminate the residual toner after the toner image is transferred, a so-called cleanerless system is adopted. be able to. As a result, not only can the toner to be discarded be eliminated, but also the cleaning device can be omitted, and the image forming system can be simplified and the cost of the image forming device can be reduced. However, at present, it is difficult to make the transfer rate of the toner image 100%, and there is a problem from the viewpoint of reliability.

Therefore, as a next best measure, the transfer residual toner remaining on the surface of the image carrier after the transfer of the toner image is recovered by adhering it to a cleaning member which rotates in contact with the image carrier. A method has been proposed in which toner is reattached to an image carrier, collected by a developing device, and reused (see, for example, Japanese Patent Publication No. 61-30274). After the transfer of the toner image, the transfer residual toner remaining on the image carrier is electrostatically temporarily collected by the cleaning member, and then the collected toner is transferred to the next electrostatic latent image on the image carrier. The toner that is electrostatically redeposited on the surface portion that does not influence the formation and that is redeposited on the surface of the image bearing member is electrostatically collected by the developing device. This eliminates the need for a dedicated means for transferring the toner collected from the image bearing member to a waste toner tank or a developing device, so that the cost of the image forming apparatus can be reduced and the toner can be recycled. The waste toner can be eliminated.

In this type of image forming apparatus, the cleaning member is brought into contact with the surface of the image carrier to recover the transfer residual toner on the surface of the image carrier, and then the recovered toner is returned to the surface of the image carrier. Is configured. that time,
If the cleaning member is always kept in contact with the surface of the image carrier and the cleaning member is brought into contact with the image carrier even when the image forming apparatus is not operating, a large external force is applied to the cleaning member from the image carrier. Remains applied, the cleaning member is permanently deformed early, which reduces the cleaning performance of the cleaning member with respect to the image carrier. Further, when the cleaning member is in contact with the image carrier for a long time when the image forming apparatus is not operating, toner adheres to the surface of the image carrier, and when the image forming operation is performed, the adhered toner may cause A so-called blank area phenomenon occurs in which a part of the image is missing.

Therefore, there has been proposed a structure in which the cleaning member is rocked so as to be separated from the surface of the image carrier when the image forming apparatus is not in operation. With this configuration, the above-mentioned problems can be eliminated, but a complicated swing contact / separation device for bringing the cleaning member into and out of contact with the image carrier is required, which complicates the configuration of the image forming apparatus. In addition, there is a problem that the cost becomes high.

[0008]

SUMMARY OF THE INVENTION An object of the present invention is to collect transfer residual toner on a cleaning member, reattach the recovered toner to an image carrier, and then collect the reattached toner on a developing device. SUMMARY OF THE INVENTION An object of the present invention is to provide an image forming apparatus which eliminates the above-mentioned conventional drawbacks of the image forming apparatus, and which has a simple structure and can prevent the cleaning member from being permanently deformed early and the toner from being fixed to the image carrier.

[0009]

In order to achieve the above object, the present invention is directed to an image carrier which is driven to rotate, a latent image forming means for forming an electrostatic latent image on the carrier, and an electrostatic latent image forming means. A developing device that visualizes the latent image as a toner image, a transfer device that transfers the toner image on the image carrier to a recording medium, and a transfer residual toner on the image carrier after the toner image is transferred are electrostatically charged. And a cleaning member for electrostatically redepositing the collected toner on the surface of the image carrier that does not affect the formation of the next electrostatic latent image. In an image forming apparatus that electrostatically collects toner re-adhered to the body surface in a developing device, a cleaning member is configured as a rotating body rotatably supported around an axis whose position is fixed, and its rotation Depending on the position, contact with the surface of the image carrier, or The cleaning residual surface adheres to the surface of the image carrier, and the residual toner adhered to the surface of the image carrier is recovered on the cleaning surface of the cleaning member, and the recovered toner is re-adhered to the surface of the image carrier. The surface is in contact with the surface of the image carrier, and at other times, at least when the image forming apparatus is not operated, the cleaning surface is separated from the surface of the image carrier,
An image forming apparatus is proposed which is provided with a cleaning member rotation drive control means for controlling the rotation of the cleaning member.

At this time, the cleaning member has a core shaft extending substantially parallel to the image bearing member, and a main body portion integrated with the core shaft and extending substantially parallel to the image bearing member. The shape of the main body is set to a shape in which a part of the cylindrical body around the axis of the core axis in the circumferential direction is cut out, and the peripheral surface other than the cut out portion constitutes the cleaning surface. It is advantageous.

Particularly, it is advantageous that the cross-sectional shape of the main body of the cleaning member is set to a fan shape.

Further, the cleaning member includes a core shaft extending substantially parallel to the image carrier and a cylindrical main body which is integrated with the core shaft and extends substantially parallel to the image carrier. It is advantageous that the cylindrical main body is fixed in an eccentric state with respect to the core shaft, and a part of the peripheral surface of the cylindrical main body constitutes the cleaning surface.

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below in detail with reference to the drawings.

FIG. 1 is a schematic configuration diagram showing an example of an image forming apparatus according to the present invention. In the figure, a drum-shaped photoconductor 1 which is an example of the structure of an image carrier is rotationally driven in the clockwise direction in the figure by a drive device (not shown), and at this time, a static elimination lamp 13 which is an example of the static eliminator removes static electricity. The surface of the photoconductor 1 is uniformly charged to a predetermined polarity by the action of the charging roller 2 which is an example of a charging device. In this example, the charging roller 2 is connected to the voltage power source E ₁₀ , and uniformly charges the surface of the photoconductor 1 to a negative (negative) polarity while rotating in contact with the photoconductor 1. Due to the action of the charging roller 2, the surface of the photoconductor 1
For example, it is charged to -850V. As a charging device for uniformly charging the photoreceptor 1, a charging device disposed apart from the photoreceptor, such as a corona discharger, can be used.

Next, in the exposure unit 3, an exposure scanning device (not shown) performs, for example, optical writing scanning by the light-modulated laser beam 11, so that a predetermined electrostatic latent image is formed on the surface of the photoconductor 1. An image is formed. The surface potential of the laser light 11 on the photoconductor 1, that is, the surface potential of the electrostatic latent image is, for example, about −150 V, and the portion B where the laser light 11 is not irradiated, that is, the surface of the background portion of the electrostatic latent image. The potential is maintained at approximately -850V. As described above, in this example, the charging roller 2 and the exposure scanning device form a latent image forming unit that forms an electrostatic latent image on the image carrier made of the photoconductor 1.

The developing device 4 is provided with a developing roller 5 which is an example of a developer carrying and conveying member arranged to face the photoconductor 1, and a pair of stirring paddles 10A and 10B, which are the developing casing 9 of the developing device. Each is provided inside and is rotatably supported by the casing 9. Of these, the developing roller 5 is supplied with a voltage power source E ₁ , for example, -600V.
Voltage is applied. The photoconductor 1 is attached to the developing roller 5.
A voltage having the same polarity as the charging polarity of is applied.

In the developing device 4 illustrated here, a two-component developer D having a toner and a carrier is used, and the developer D is contained in the developing casing 9. Then, as the stirring paddles 10A and 10B rotate, the toner is charged to a predetermined polarity by friction with the carrier, that is, the same polarity as the charging polarity of the photoconductor 1 in this example, that is, a negative polarity. As described above, in the image forming apparatus of this example, the charging polarity of the toner during development is negative. A developing device using a one-component developer having no carrier may be employed.

The developing roller 5 is driven to rotate counterclockwise in the drawing, and the developer carried on the peripheral surface of the developing roller 5 is conveyed in the rotating direction of the developing roller 5, and the roller 5 is rotated.
The developer regulating member 15 oppositely arranged with a predetermined gap therebetween is scraped. The developer whose conveyance amount is regulated by the developer regulating member 15 is conveyed toward the developing section 6 where the developing roller 5 and the photoconductor 1 face each other, and the toner in the developer is conveyed to the photoconductor by the developing section 6. 1 is electrostatically attracted to the electrostatic latent image on 1 and adheres to that portion. That is, the toner charged to the negative polarity, which is the same as the charging polarity of the photoconductor, adheres to the surface portion A of the photoconductor irradiated with the laser beam, and the electrostatic latent image is visualized as a toner image. As described above, the image forming apparatus of this embodiment employs the reversal development method (negative / positive development method).

A transfer roller 7, which is an example of a transfer device, is disposed below the photoconductor 1. The transfer roller 7 rotates in the forward direction with respect to the rotation direction of the photoconductor 1, and toward the transfer portion 8 between the transfer roller 7 and the photoconductor 1 facing the transfer roller 7, a recording medium made of a transfer paper 16 is formed. Are transferred in the direction of the arrow P, and the transfer roller 7 is pressed against the surface of the photoconductor 1 via the transfer paper 16 sent to the transfer unit 8, and at this time, the function of the transfer roller 7 causes the photoconductor to move. The toner image formed on the transfer sheet 1 is transferred onto the transfer paper 16. That is, the power source E _{3 is applied} to the transfer roller 7 so that
Positive (plus) polarity voltage opposite to the charge polarity of the above toner,
For example, a voltage of + 950V is applied, and at this time, the negative toner T on the photoconductor 1 is electrostatically attracted to the transfer paper 16 side and adheres to the transfer paper. It is also possible to use a transfer device separated from the photoconductor 1 such as a transfer device including a corona discharger. Note that FIG. 1 schematically shows the toner on the photoconductor 1 in an enlarged manner (the same applies to FIG. 2).

The transfer paper 16 on which the toner image has been transferred is separated from the photoconductor 1 by a separating device (not shown), and is sent to a fixing device (not shown).
The toner image on 6 is fixed. In this way, the transfer paper 16 is ejected outside the image forming apparatus main body as copy paper.

As described above, the image forming apparatus of this embodiment has the image carrier composed of the photosensitive member 1 which is rotationally driven, the latent image forming means for forming an electrostatic latent image on the image carrier, and the latent image forming means. The developing device 4 visualizes the electrostatic latent image as a toner image, and the transfer device 7 includes a transfer roller 7 for transferring the toner image on the image carrier to a recording medium composed of the transfer paper 16. It is provided with a static eliminator including the above-mentioned static eliminator 13, a cleaning member 12 described below, and a cleaning member rotation drive control means described later. The latent image forming means, the developing device, the transfer device, the cleaning member, and the charge eliminating device are arranged in that order around the image carrier in the rotation direction of the image carrier.

The toner image on the photoconductor 1 is transferred to the transfer paper 16 at the transfer section 8. After the toner image is transferred, the photoconductor 1 is transferred.
The toner remaining on the photoconductor 1 without being transferred to the transfer paper 16 adheres to the surface of the. Transfer residual toner T ₁
Reach the cleaning unit 14, the cleaning member 12
Will be temporarily collected.

As will be described in detail later, the cleaning member 12 includes a core shaft 1 made of a conductive rigid body such as metal.
2B and a main body 12A integrated with the main body 2A. The main body 12A is made of a conductive or medium-resistive elastic body such as foam. The main body portion 12A of the cleaning member 12 shown in FIG. 1 has a fan-shaped transverse cross-sectional shape, which will be described later in detail.

The main body 12A of the cleaning member 12 is housed in the cleaning case 17, and each end of the core shaft 12B is rotatably but movably supported by the cleaning case 17. The cleaning member 12 is located in parallel with the photoconductor 1 together with the developing roller 5, the charging roller 2, and the transfer charging roller 7.

In FIG. 1, most of the toner T of the toner image directed from the developing section 6 to the transfer section 8 is a toner having a charging polarity at the time of development, that is, a negative polarity toner. On the other hand, when the toner image is transferred, a voltage having a polarity opposite to the toner charging polarity at the time of development, which is a positive polarity in this example, is applied to the transfer roller 7, so that the toner remains on the photoconductor 1 after the toner image is transferred. The toner that adheres, that is, the transfer residual toner T ₁ is a mixture of positive and negative toner. The transfer residual toner is transferred to the cleaning unit 14 in a state in which both positive and negative polarity toners are mixed.

The cleaning member 12, when collecting the residual toner T ₁ of the the photosensitive member 1, while in contact with the cleaning surface 12C the surface of the photosensitive member 1 which is the outer peripheral surface of the main body portion 12A, a timepiece according to FIG. 1 Direction, that is, in the counter direction (direction of arrow a) with respect to the rotation direction of the photoconductor 1,
The cleaning member rotation drive control means, which will be described later, is configured to rotate and drive from the position shown in FIG. 1 to the position shown in FIG. 4, and the cleaning surface 12C rotates while sliding on the surface of the photoconductor 1. Cleaning member 12
Is pressed against the photoconductor 1 so that its main body 12A is elastically deformed by the photoconductor 1, and as shown in FIG. 2, a predetermined nip region N is formed at this press contact part.
The nip area N serves as the cleaning unit 14. The width of the nip region N in the circumferential direction of the photoconductor is, for example, about 1 mm, but in FIGS. 1 and 2, the width of the nip region N is exaggerated and enlarged for the sake of clarity. 4, FIG. 6 and FIG. 7).

In the above-mentioned nip area N, the transfer residual toner T ₁ of both positive and negative polarities is transferred to the main body ₁ of the cleaning member 12.
While being in contact with 2A, the toner is triboelectrically charged so that the toner has the same polarity (negative polarity in this example) as the toner at the time of development. The transfer residual toner T ₁ is made to have a negative polarity, which is the charging polarity during development.

Thus, the cleaning member 12 of this example.
The main body portion 12A also performs a function of frictionally charging the transfer residual toner with the photoconductor 1 and frictionally charging the toner so that the toner is aligned in the negative polarity which is the original polarity. That is, when the transfer residual toner directed toward the cleaning member 12 includes toner charged to a polarity opposite to the charging polarity of the toner at the time of development, the toner has the charging polarity (original polarity) of the toner at the time of development. The toner is triboelectrically charged so that it can be aligned.

Returning to FIG. 1, the transfer residual toner T ₁ on the photoconductor ₁ is cleaned by the cleaning surface 12C of the cleaning member 12.
When collecting the cleaning member 12, the core shaft 12 of the cleaning member 12
A voltage having a polarity opposite to the charging polarity of the toner triboelectrically charged by the member 12, that is, a positive voltage in this example, for example, a voltage of +200 V is applied to B by the voltage power source E ₄ . Therefore, the residual toner after transfer of the toner image, which has passed through the transfer portion 8, that is, the residual transfer toner T ₁ is electrostatically attracted to the cleaning member 12 to which a positive voltage is applied, and the cleaning surface of the member 12 is cleaned. It adheres to 12C and is temporarily collected by this member. As a result, the surface of the photoconductor 1 is cleaned. A cleaning member 12 that rotates while contacting the photoreceptor 1 at a predetermined angle.
In this way, in order to form an electric field in which the transfer residual toner on the photoconductor is electrostatically attracted toward the cleaning member 12 between the photoconductor 1 and the toner during development, A voltage having a polarity opposite to the charging polarity (in this example, a positive polarity) is applied.

After the surface of the photoconductor 1 is cleaned by the cleaning member 12, the surface is subjected to the charge removal action by the charge removal lamp 13, and the above-mentioned image forming operation is continued. In this way, one toner image is formed on the photoconductor 1 and is transferred to the transfer paper 16. The region on the photoconductor 1 on which the toner image is formed is the image forming region. The area after that is the non-image forming area. When the rear end of the image forming area in the rotation direction of the photoconductor passes through the charging roller 2, at this time, the charging roller 2
Are separated from the surface of the photoconductor 1. At the same time, the switch S ₁₀ is switched to turn off the voltage application to the charging roller 2.

When the trailing edge of the image forming area passes the developing roller 5 of the developing device 4, the switch S ₁ is switched, the developing roller 5 is connected to the voltage power source E ₂ , and the developing roller 5 is charged with toner. To prevent the toner from adhering to the photoconductor 1, a positive polarity voltage opposite to the charging polarity of the toner, for example + 500V
Is applied. When the trailing edge of the image forming area passes through the transfer portion 8, the voltage application to the transfer charging roller 7 is stopped at this time.

[0032] The cleaning member 12 is to collect the residual toner T ₁ of the the photosensitive member 1 after the transfer of the toner image electrostatically temporarily such recovery, the cleaning member 12 as described above, FIG. 1 This is performed while rotating from the position shown in to the position shown in FIG. 4 in the counter direction with respect to the rotation direction of the photoconductor 1. The cleaning member 12 then electrostatically redeposits the collected toner T ₂ (FIG. 2) on the surface portion of the photoconductor 1 that does not affect the formation of the next latent image.
For example, when the rear end of the image forming area after the toner image is transferred to the transfer paper 16 passes the cleaning member 12,
The switch S ₂ is switched, the cleaning member 12 is connected to the voltage power source E ₅ , and the cleaning member 1
2 has a negative polarity, for example, −3000 V, which is the same as the charging polarity of the toner frictionally charged by the cleaning member.
Is applied. Cleaning member 12 and photoconductor 1
An electric field in the direction in which the toner on the cleaning member 12 is discharged toward the photoconductor 1 is formed between the non-image forming region and the non-image forming region.

Due to the electric field, the cleaning member 1
The toner temporarily collected on the toner 2 is reattached to the non-image forming area on the photoconductor 1 and returned. This reattachment operation is
This is performed while the cleaning member 12 rotates from the position shown in FIG. 4 in the forward direction with respect to the rotation direction of the photoconductor 1 to the position shown in FIG.

In this way, the toner redeposited on the photoconductor 1 passes under the charge removing roller 13 and the charging roller 2 separated from the photoconductor 1 by the subsequent rotation of the photoconductor 1, and reaches the developing device 4. Reach At this time, as described above, since the positive polarity voltage opposite to the charging polarity of the toner at the time of development is applied to the developing roller 5, the negative polarity toner redeposited on the photoconductor 1 is It electrostatically moves to the developing roller 5 side and is collected in the developer in the developing device.

As described above, the toner temporarily collected by the cleaning member 12 is redeposited on the image carrier made of the photoconductor 1, and the redeposited toner is electrostatically charged by the developing device 4. to recover. The toner collected in the developing device 4 is reused in the developing device 4. In this way, waste toner can be eliminated, and it is not necessary to provide a toner conveying pipe or the like for returning the toner collected by the cleaning member to the developing device. When the image forming operation is continuously performed, the toner collection and the re-adhesion operation are repeated a predetermined number of times.

The toner collected by the cleaning member 12 re-adheres to the non-image forming area on the photoconductor 1, so that the re-adhering toner causes not only the electrostatic latent image at the time of the above-mentioned image forming operation but also the next. The formed electrostatic latent image is also not affected. The collected toner on the cleaning member 12 can be reattached to various areas on the photoconductor 1, but in any case, it is collected on the surface portion of the photoconductor 1 that does not affect the formation of the next latent image. The deposited toner is reattached.

As described above, the transfer residual toner on the image carrier is electrostatically transferred to the cleaning member by applying a bias voltage having a polarity opposite to the charging polarity of the toner at the time of development to the cleaning member. The transfer residual toner can be collected by the cleaning member. Further, after the collection, the polarity of the bias voltage applied to the cleaning member is switched, and the bias voltage having the same polarity as the charging polarity of the toner at the time of development is applied to the cleaning member, so that the toner collected on the cleaning member is carried as an image. The toner can be electrostatically transferred to the body, the collected toner can be reattached to the image carrier, and the reattached toner can be electrostatically collected in the developing device.

Here, as described above, if the cleaning member is in constant contact with the image carrier even when the image forming apparatus is not in operation, the cleaning member can be quickly activated. Permanent deformation or toner sticking to the cleaning member may reduce the collectability of the transfer residual toner. In addition, the toner adheres to the photoconductor, and the white spot phenomenon on the image easily occurs. Therefore, for example, a configuration has been proposed in which the cleaning member is oscillated in a direction in which the cleaning member is separated from the photoconductor when the image forming apparatus is not in operation. However, this configuration requires a oscillating contact / separation device for the cleaning member. Therefore, the structure of the image forming apparatus becomes complicated and the cost thereof increases.

Therefore, in the image forming apparatus of this embodiment,
As described above, the cleaning member 12 includes the core shaft 12B made of a conductive rigid body extending substantially parallel to the photoconductor 1, and the cleaning member 12 integrated with the core shaft 12B. Main body 12 made of an elastic body extending substantially in parallel
A. As shown in FIGS. 3 and 4, the main body 12A has a shape in which a part of the cylindrical body 27 (FIG. 4) around the central axis X of the core shaft 12B is cut away in the circumferential direction. The peripheral surface other than the notched portion that has been set constitutes the above-described cleaning surface 12C.

In the example shown in FIGS. 1 to 5, the cylindrical body 27 is used.
Cleaning member 1 formed by cutting away a part of
The cross-sectional shape of the second main body 12A is fan-shaped, the fan-shaped outer peripheral surface is the cleaning surface 12C, and the center of the fan is fixed to the core shaft 12B. As described above, the voltage for toner recovery and toner re-adhesion is applied to the cleaning member 12 through the core shaft 12B.

The reference numeral 17A in FIG.
These are side wall portions on both sides of the cleaning case 17 shown in FIG. 1, and each end portion of the core shaft 12B of the cleaning member 12 is rotatably supported by the bearings 18 but is fixed in position. The cleaning case 17 is fixed to the main body of the image forming apparatus, and thus the central axis X of the cleaning member 12 is also fixed. As described above, the cleaning member 12 is configured as a rotating body that is rotatably supported around the axis X whose position is fixed.

As shown in FIG. 3, a pinion 25 is fixedly mounted on the motor shaft 24a of the motor 24 whose rotation is controlled by the control unit 23. The pinion 25 is fixed to one shaft end of the core shaft 12B. It meshes with the mounted gear 26.
The motor 24 is controlled by the control signal output from the controller 23.
Can rotate forward or reverse. With this, Pinion 2
The cleaning member 12 is rotationally driven via the gear 5 and the gear 26 during the operation of collecting the transfer residual toner and the operation of reattaching the collected toner to the photoreceptor 1.

Here, at the time other than the operation of collecting the transfer residual toner and the operation of re-adhering the collected toner to the photoconductor 1, at least when the image forming apparatus is not in operation, the cleaning member 12 is It rotates to the home position shown in FIG. 5, and its cleaning surface 12C is separated from the surface of the photoconductor 1. For example, when the toner re-adhesion operation is completed and the image forming operation is not subsequently performed, the cleaning member 12 rotates counterclockwise from the position shown in FIG. 1, for example, after the re-adhesion operation is completed. The member 1
The cleaning surface 12C of No. 2 is separated from the photoconductor 1 in FIG.
It is brought to the home position shown in. That is,
The portion of the cleaning member that does not contact the photoconductor 1 is the photoconductor 1.
The cleaning member 12 rotates so as to come to a position opposite to.

On the other hand, with the start of the image forming operation, the cleaning member 12 has its cleaning surface 1
2C is rotated to the position shown in FIG. 1 where it comes into contact with the surface of the photoconductor 1, and as described above, the transfer residual toner on the photoconductor 1 is collected and the collected toner is reattached to the surface of the photoconductor 1. To do.

As described above, the cleaning member 12 is
It has a cleaning surface 12C that comes into contact with or separates from the surface of the image carrier depending on its rotational position. Further, in this example, the control unit 23, the motor 24, the pinion 25, the gear 26, and the like shown in FIG. 2 configure a cleaning member rotation drive control unit 20 that controls the rotation of the cleaning member, and the control unit 20 is a photosensitive member. When the transfer residual toner T ₁ adhered to the surface of the image carrier composed of ₁ is collected on the cleaning surface 12C of the cleaning member 12 and when the collected toner is reattached to the surface of the image carrier, the cleaning surface 12C is In contact with the surface of the image carrier, at other times, at least when the image forming apparatus is not operating,
The rotation of the cleaning member 12 is controlled so that the cleaning surface 12C is separated from the surface of the image carrier.

According to the above arrangement, the cleaning member is at a time other than when the residual transfer toner is collected and when the collected toner is not reattached to the photosensitive member, at least when the operation of the image forming apparatus is stopped. Since 12 does not contact the photoreceptor 1, permanent deformation of the main body 12A can be prevented.
Particularly, in this example, since the cleaning member 12 is pressed against the photoconductor 1 so as to be elastically deformed by the photoconductor 1, such permanent deformation can be effectively prevented. Further, it is possible to prevent the toner remaining fixed to the cleaning member from being retained, and thus it is possible to prevent deterioration of the collectability of the transfer residual toner. Further, since it is possible to prevent the toner from sticking to the photoconductor 1, it is possible to suppress the occurrence of the white spot phenomenon on the image.

Moreover, the cleaning member 12 is attached to the photoreceptor 1.
Since there is no need for a rocking drive device to be brought into contact with or separated from the device, the structure of the image forming apparatus does not become complicated and its cost does not increase. Although the central axis X of the cleaning member 12 does not move and the cleaning member 12 does not swing with respect to the photoconductor 1, the cleaning member 12 is brought into contact with and separated from the photoconductor 1 with a simple configuration. It is possible.

In the above embodiment, the cleaning member 1
Although the second main body 12A is formed in a fan shape, a cleaning member 22 as shown in FIG. 6 may be used instead.
Similar to the cleaning member 12 shown in FIG. 1, the cleaning member 22 has a conductive core shaft 22B extending substantially parallel to the photosensitive member 1 and an integrated unit of the core shaft 22B with respect to the photosensitive member 1. And has a main body 22A made of, for example, an elastic body such as foam, and the cleaning member 22 is also configured as a rotating body supported around an axis X whose position is fixed.

Further, the main body portion 22A of the cleaning member 22 is also configured such that its shape is formed by cutting out a part of the cylindrical body around the axis X of the core shaft 22B in the circumferential direction, and the cutout portion. The peripheral surface other than the above constitutes a cleaning surface 22C that functions in the same manner as the cleaning surface 12C of the cleaning member 12 shown in FIG. That is, flat cutouts 22D, 22D that do not contact the photoconductor 1 are provided on a part of the peripheral surface of the main body 22A, and the flat cutouts 22D are adjacent to each other in the circumferential direction. In position.

The cleaning member 22 is placed so that the cleaning surface 22C is in a position in contact with the photoconductor 1 during the operation of collecting the transfer residual toner and the operation of reattaching the recovered toner, and during the operation of collecting the transfer residual toner. , The flat cutout portion 2 at a time other than the operation of reattaching the collected toner
One of 2D and 22D is brought to a position facing the photoconductor 1 so that the cleaning member 22 does not come into contact with the photoconductor 1 and rotation is controlled by the cleaning member rotation drive control means. Flat cutout 22D
As for the above, there may be one location or three or more locations.

As described above, also in the example shown in FIG. 6, the cleaning member 22 has the cleaning surface 22C which comes into contact with or separates from the surface of the image bearing member depending on its rotational position. The transfer residual toner adhering to the surface of the image carrier composed of the body 1 is cleaned by the cleaning member 22.
The cleaning surface 22C comes into contact with the surface of the image carrier when the toner is collected on the cleaning surface 22C and when the collected toner is reattached to the surface of the image carrier, and at other times, at least during image formation. Cleaning member rotation drive control means for controlling the rotation of the cleaning member 22 is provided so that the cleaning surface 22C is separated from the surface of the image carrier when the apparatus is not in operation.

As the cleaning member, an eccentric cleaning member 32 may be used as shown in FIG. The cleaning member 32 has a conductive core shaft 32B extending substantially parallel to the image carrier made of the photoconductor 1.
And a main body 32A made of a cylindrical elastic body that is integrated with the core shaft 32B and extends substantially parallel to the image carrier.
And the cylindrical main body 32A is fixed in an eccentric state with respect to the core shaft 32B, and a part of the peripheral surface of the cylindrical main body 32A cleans the cleaning member 12 shown in FIG. Cleaning surface 32C similar to surface 12C
Is composed. The core shaft 32B has a cylindrical main body 3
It occupies a position eccentric to the center of 2A by a predetermined distance.

The cleaning surface 32C of the cleaning member 32, which is a part of the peripheral surface of the cleaning member 32, comes into contact with the photoconductor 1 during the recovery operation of the transfer residual toner and the reattachment operation of the recovered toner, as shown in FIG. The rotation shaft occupies the rotation position and is rotated by 180 ° from the position shown in the figure at a time other than the operation of collecting the residual transfer toner and the time of the operation of re-adhering the collected toner, and the core shaft 32B is rotated. The peripheral surface portion 32D on the side closer to is opposed to the photoconductor 1.
At this position, the peripheral surface portion 32D is held in a non-contact state with the photoconductor 1. The rotation control of the cleaning member 32 is also performed by the above-mentioned cleaning member rotation drive control means.

Thus, also in the example shown in FIG.
The cleaning member 32 has an axis X whose position is fixed.
It is configured as a rotating body that is rotatably supported around,
It has a cleaning surface 32C which comes into contact with or separates from the surface of the image carrier made of a photoconductor depending on its rotational position, and transfer residual toner adhering to the surface of the image carrier is transferred to the cleaning surface 32C of the cleaning member 32. The cleaning surface 32C comes into contact with the surface of the image carrier when the toner is collected and when the collected toner is reattached to the surface of the image carrier, and at other times, at least when the image forming apparatus is not in operation. A cleaning member rotation drive control means for controlling the rotation of the cleaning member 32 is provided so that the cleaning surface 32C is separated from the surface of the image carrier.

When the cleaning members 12, 22, 32 shown in the above-mentioned specific examples collect the transfer residual toner on the photoconductor 1, and when the collected toner is reattached to the photoconductor 1, The direction in which the cleaning member rotates can be set as appropriate, and the cleaning member can be stopped during these operations.

However, as described above with reference to FIGS. 1 to 4, when the cleaning member 12 is rotated in the counter direction with respect to the rotation direction of the photosensitive member 1 at the time of collecting the transfer residual toner T ₁ , The following advantages are obtained.

Photoreceptor 1 which has passed through transfer portion 8 shown in FIG.
As described above, the transfer residual toner T ₁ contains toner charged with a polarity opposite to the charging polarity of the toner at the time of development (abnormal polarity toner), and in the example shown in FIG. , The abnormal polarity toner is triboelectrically charged with the cleaning surface 12C of the cleaning member 12,
It is arranged to have the same polarity as the charging polarity of the toner during development.

However, the nip area N shown in FIG.
It is difficult to completely align the charge polarities of the transfer residual toners existing in the above, and there may be some toners that remain the charge polarities opposite to the charge polarities of the toners at the time of development, that is, abnormal polarity toners. . When the toner is collected, the cleaning member 12 is applied with a voltage having a polarity opposite to the charging polarity of the toner during development as described above, and the toner having the charging polarity during development electrostatically transfers to the cleaning member 12. The toner is collected on the cleaning surface 12C of the member 12, and at this time, the toner (abnormal polarity toner) having a polarity opposite to the charging polarity at the time of development is mechanically scraped by the cleaning member 12. Due to the force, it adheres to the surface of the cleaning member 12. If such abnormal polarity toner is transferred to the photoconductor 1 during the toner recovery operation from the photoconductor 1,
Background stains on the image and stains on the charging roller 2 are likely to occur.

On the other hand, in the cleaning member 12 shown in FIG. 1, as shown in FIG. 2, the transfer residual toner T ₁ is transferred from the photosensitive member 1 to the cleaning surface 12 of the cleaning member 12.
When collecting to C, as described above, in the contact area between the photoconductor 1 and the cleaning member 12, that is, in the nip area N where these are in pressure contact, they both move in opposite directions (counter direction). Further, the rotation direction of the cleaning member 12 is set. The cleaning member 12 rotates in the direction of arrow a in FIG.

With this configuration, the toner T ₂ collected by the cleaning member 12 does not come into contact with the photosensitive member 1 again during the toner collecting operation. Moreover, it is possible to prevent the abnormal polarity toner collected on the cleaning member 12 from being electrostatically transferred to the surface of the photoconductor 1 after cleaning during the toner collecting operation.

If the transfer residual toner T ₁ is collected, the cleaning member 12 is rotated in a direction in which the cleaning member 12 and the photoconductor 1 move in the same direction in the nip region N as shown in FIG. If so, the collected toner T is collected on the cleaning member 12 on the downstream side in the rotation direction of the photoconductor 1.
₃ is present, and if the toner T ₃ is an abnormal polarity toner that is still charged in the positive polarity, the cleaning member 12 is applied with the same positive polarity voltage when the toner is collected, The positive polarity toner T
₃ is electrostatically attracted to the photoconductor 1 and adheres to the photoconductor surface. In this case, the cleaning failure of the photoconductor 1 occurs, and the toner adheres to the charging roller 2, so that the toner image formed subsequently has a background stain.

In order to eliminate such a problem, as described above, the cleaning member 12 is rotated so that the cleaning member 12 rotates in the counter direction with respect to the rotation direction of the photosensitive member 1, that is, in the direction of the solid arrow a in FIG. The direction is set.

According to the above construction, the cleaning member 12
It is possible to make it difficult to transfer the toner (abnormal polarity toner) having a polarity opposite to the charge polarity at the time of development, which has been collected, to the photoconductor 1. Such a configuration can also be applied to the cleaning members 22 and 32 shown in FIGS. 6 and 7.

When the collected toner on the cleaning member 12 is reattached to the photoconductor 1, the cleaning member 12 may be rotated in any direction. In this example, as described above, the nip region with the photoconductor 1 is set. At N, the rotation direction of the cleaning member 12 is controlled so that the cleaning member 12 and the photoconductor 1 rotate in the same direction (the direction of the chain line arrow b in FIG. 2). Moreover, the rotation speed thereof is set higher than that at the time of toner recovery, and the photosensitive member 1 is rotated at a speed higher than the peripheral speed so that the toner can be reattached to the photosensitive member 1 efficiently in a short time.

The present invention can be applied to an image forming apparatus using an endless belt-shaped image carrier as well as a drum-shaped image carrier. Also, using an intermediate transfer member as a recording medium,
It can also be applied to an image forming apparatus of a type in which a toner image is transferred from an image carrier to this intermediate transfer member and then transferred to a transfer material. Further, according to the present invention, after the image carrier is charged by the charging means, an electrostatic latent image is formed by a portion which is not irradiated with light, and toner charged with a polarity opposite to the polarity of the potential is attached to develop the latent image. It is also applicable to a so-called positive / positive developing type image forming apparatus.

[0066]

According to the image forming apparatus of the first aspect, the time other than the operation of collecting the transfer residual toner on the cleaning member and the operation of re-adhering the collected toner to the image carrier, At least when the image forming apparatus is not in operation, the cleaning member does not come into contact with the image bearing member, so that the permanent deformation of the cleaning member can be prevented, and the collectability of the transfer residual toner and the durability of the cleaning member are deteriorated. It can be prevented. Further, since it is possible to prevent the toner from being fixedly adhered to the cleaning member, it is possible to prevent deterioration of the collectability of the transfer residual toner. Further, since it is possible to prevent the toner from sticking to the image carrier, it is possible to suppress the occurrence of white spots on the image. In addition to this point, there is no need for means for swinging the cleaning member to bring it into contact with or separate from the image carrier, so that the configuration of the image forming apparatus can be simplified.

According to the image forming apparatus of the second aspect,
With the cleaning member having a simple shape, it is possible to achieve the above-described effects.

According to the image forming apparatus of the third aspect,
The shape of the cleaning member can be particularly reduced.

According to the image forming apparatus of the fourth aspect,
The shape of the cleaning member can be simplified, and its manufacturing cost can be reduced.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram of an image forming apparatus according to an exemplary embodiment of the present invention.

FIG. 2 is an explanatory view showing, in an enlarged manner, a contact portion of both of the photosensitive member and a cleaning member in order to explain that the charging polarities of the toner are made uniform;

3 is a perspective view showing a configuration of a cleaning member included in the image forming apparatus shown in FIG. 1 and an example of a rotation drive control unit thereof.

FIG. 4 is a schematic view showing a cleaning member and a part of a photosensitive member for explaining a state in which the cleaning member shown in FIG. 1 has rotated to a transfer residual toner collecting operation end position.

FIG. 5 is a schematic view showing a state where the cleaning surface of the cleaning member is separated from the photoconductor.

FIG. 6 is a schematic view showing a cleaning member of another example and a part of a photoconductor.

FIG. 7 is a schematic view showing a cleaning member of another example and a part of the photoconductor.

[Explanation of symbols]

4 Developing Device 12 Cleaning Member 12A Main Body 12B Core Shaft 12C Cleaning Surface 20 Cleaning Member Rotation Drive Control Means 22 Cleaning Member 22A Main Body 22B Core Shaft 23C Cleaning Surface 27 Cylindrical Body 32 Cleaning Member 32A Main Body 32B Core Shaft 32C Cleaning Surface T ₁ toner X axis

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Masako Yoshii 1-3-6 Nakamagome, Ota-ku, Tokyo Inside Ricoh Co., Ltd.

Claims (4)

[Claims] 1. An image carrier that is driven to rotate, a latent image forming unit that forms an electrostatic latent image on the carrier, and a developing device that visualizes the electrostatic latent image as a toner image. A transfer device that transfers the toner image on the image carrier to the recording medium, and electrostatically temporarily collects the transfer residual toner on the image carrier after the toner image is transferred, and then collects the collected toner on the image carrier. A cleaning member for electrostatically re-adhering to a surface portion of the body that does not affect the formation of the next electrostatic latent image, and the toner re-adhering to the surface of the image carrier is electrostatically charged in the developing device. In the image forming apparatus that collects the image, the cleaning member is configured as a rotating body that is rotatably supported about an axis whose position is fixed, and contacts the surface of the image carrier or separates from the surface depending on the rotating position. It has a cleaning surface, When the transfer residual toner adhering to the surface is collected on the cleaning surface of the cleaning member and when the collected toner is redeposited on the surface of the image carrier, the cleaning surface contacts the surface of the image carrier, and The image is characterized in that a cleaning member rotation drive control means for controlling the rotation of the cleaning member is provided so that the cleaning surface is separated from the surface of the image carrier at least when the image forming apparatus is not in operation. Forming equipment. 2. The cleaning member has a core shaft extending substantially parallel to the image bearing member, and a main body unit integrated with the core shaft and extending substantially parallel to the image bearing member.
The shape of the main body is set to a shape in which a part of the cylindrical body around the axis of the core shaft in the circumferential direction is cut out, and the peripheral surface other than the cut out portion constitutes the cleaning surface. 1. The image forming apparatus according to 1. 3. The image forming apparatus according to claim 2, wherein the main body of the cleaning member has a fan-shaped cross section. 4. The cleaning member includes a core shaft extending substantially parallel to the image bearing member, and a cylindrical main body portion integrated with the core shaft and extending substantially parallel to the image bearing member. The image according to claim 1, wherein the cylindrical main body is fixed in a state of being eccentric with respect to the core axis, and a part of the peripheral surface of the cylindrical main body constitutes the cleaning surface. Forming equipment.