JPH09197932A - Image forming device - Google Patents

Abstract

(57) Abstract: An image forming apparatus that collects transfer residual toner on a cleaning roller, reattaches the collected toner to a photoconductor, and then collects the reattached toner on a developing device. The toner filming on the photoconductor can be removed without using a filming removing member. SOLUTION: During a normal image forming operation, a cleaning roller 12 is rotated in a forward direction with respect to a rotation direction of a photoconductor 1, and when removing filming of the photoconductor 1, the cleaning roller 12 is moved in a rotation direction of the photoconductor. On the other hand, rotate it toward the counter.

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 toner image is transferred is adhered to the cleaning member to be recovered, and then the recovered toner is re-adhered to the image carrier. , A method of collecting with a developing device and reusing it has been proposed (for example, Japanese Patent Publication No.
-30274 publication). After the toner image is transferred, the transfer residual toner remaining and attached on the image carrier is temporarily collected by the cleaning member, and the collected toner is affected by the formation of the next electrostatic latent image on the image carrier. The toner re-adhered to the non-existing surface portion and further re-adhered to the surface of the image carrier is collected by the developing device. This eliminates the need for a dedicated means for transferring the collected toner to a waste toner tank or a developing device, thus reducing the cost of the image forming apparatus and reusing the toner. It can be lost.

In the image forming apparatus of the above type, the cleaning member is brought into pressure contact with the surface of the image carrier to collect the transfer residual toner and to reattach the collected toner to the surface of the image carrier. There is. At that time, the rotation direction of the cleaning member with respect to the rotation direction of the image carrier can be appropriately set. For example, in the pressure contact portion between the cleaning member and the image carrier, the cleaning member moves in the opposite direction to the image carrier, That is, the rotation direction of the cleaning member can be set so that both rotate in the counter direction. However, in this case, the cleaning member always rotates in the counter direction with respect to the image carrier when the toner is collected and the toner is reattached, so that the cleaning member always receives a large external force from the image carrier. Therefore, the surface of the cleaning member may deteriorate relatively early and its life may be shortened. Therefore, from the viewpoint of extending the life of the cleaning member, the cleaning member moves in the same direction with respect to the image carrier at the pressure contact portion between the image carrier and the cleaning member at the time of collecting and re-adhering the transfer residual toner. Thus, it is preferable to set the rotation direction of the cleaning member so that both of them rotate in the forward direction.

On the other hand, in the image forming apparatus of the above-mentioned type, the toner image is repeatedly formed on the image carrier, and the surface of the image carrier is cleaned after the toner image is transferred. The toner adheres to the film like a film. This is called "toner filming", but when the occurrence of such toner filming becomes remarkable, "blurring" occurs in the obtained image, and the image quality deteriorates.

Therefore, in the conventional image forming apparatus,
A dedicated filming removing member is provided, and this is rubbed relative to the surface of the image bearing member to remove the toner filming on the image bearing member, thereby preventing the problem that the image quality is deteriorated. However, if such a dedicated filming removal member is provided, the structure of the image forming apparatus becomes complicated and large, and the cost thereof is inevitable.

Under these circumstances, the present inventor has made a detailed study of the image forming apparatus of the type described above, and when the transfer residual toner on the image carrier is collected by the cleaning member, When the cleaning member and the image carrier are rotated in the counter direction when the toner is returned to the image carrier and redeposited, the toner filming on the image carrier can be removed by the external force received from the cleaning member. I was able to find the facts. That is, at the time of collecting toner or reattaching the toner, the cleaning member moves in the opposite direction to the image carrier at the pressure contact portion between the cleaning member and the image carrier.
By setting the rotation direction of the cleaning member, it is possible to prevent the occurrence of significant toner filming on the image carrier without using a dedicated filming removal member, and prevent deterioration of image quality due to the filming. Can be done.

However, as described above, if the cleaning member is always rotated in the counter direction with respect to the image carrier, a large load is applied to the cleaning member and its life is shortened. Therefore, in this sense, it is preferable to set the rotation direction of the cleaning member so that the cleaning member moves in the same direction as the image carrier at the pressure contact portion between the cleaning member and the image carrier. Then, the toner film on the image carrier cannot be sufficiently removed by the cleaning member. Therefore, when the cleaning member is rotated in the forward direction with respect to the image carrier, it is necessary to provide a dedicated filming removing member, which cannot avoid the above-mentioned drawbacks.

[0011]

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. In addition, the above-mentioned problems in the image forming apparatus of the type in which the cleaning member is rotated in the forward direction with respect to the image carrier at the time of collecting the transfer residual toner and reattaching the collected toner to the surface of the image carrier are solved. An object of the present invention is to provide an image forming apparatus capable of preventing the life of the cleaning member from decreasing and eliminating the dedicated filming removing member.

[0012]

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 transfer is temporarily collected. And a cleaning member for reattaching the collected toner to the surface portion of the image bearing member that does not affect the formation of the next electrostatic latent image, and the toner reattached to the surface of the image bearing member. And the cleaning member is brought into pressure contact with the surface of the image carrier, and the cleaning member is rotated in a direction in which the cleaning member moves in the same direction with respect to the image carrier at the pressure contact portion. Collection of transfer residual toner, In the image forming apparatus that re-attaches the collected toner of the above to the surface of the image carrier, the cleaning member is pressed against the surface of the rotating image carrier so that the cleaning member performs the filming removal operation of the image carrier. Then, there is proposed an image forming apparatus characterized in that the pressing member has a cleaning member drive control means for rotating the cleaning member in a direction in which the cleaning member moves in a direction opposite to the image carrier (claim 1). ).

Further, in order to achieve the same object, the present invention achieves the same object by rotating the image carrier, latent image forming means for forming an electrostatic latent image on the carrier, and the electrostatic latent image as a toner. A developing device that visualizes an 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 transfer is temporarily collected, and then A cleaning member for reattaching the collected toner to a surface portion of the image bearing member that does not affect the formation of the next electrostatic latent image, and the toner reattached to the surface of the image bearing member is used in the developing device. At the same time as collecting, the cleaning member is brought into pressure contact with the surface of the image bearing member, and at the pressure contact portion, the cleaning member is rotated in a direction in which the cleaning member moves in the same direction with respect to the image bearing member, and Recovery and its recovery In an image forming apparatus for reattaching the cleaning member to the surface of the image carrier, the cleaning member is pressed against the surface of the rotating image carrier in order to cause the cleaning member to perform the filming removal operation of the image carrier. The cleaning member drive control unit that rotates the cleaning member, and the pressure contact force of the cleaning member with respect to the image carrier during the rotation thereof becomes stronger than when the transfer residual toner is collected and when the collected toner is reattached to the image carrier. In this way, an image forming apparatus is proposed which has a pressing force switching means for switching the pressing force of the cleaning member against the image carrier (claim 2).

Further, in order to achieve the same object, the present invention further comprises an image carrier which is rotationally driven, a latent image forming means for forming an electrostatic latent image on the carrier, and the electrostatic latent image as a toner. A developing device that visualizes an 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 transfer is temporarily collected, and then A cleaning member for reattaching the collected toner to a surface portion of the image bearing member that does not affect the formation of the next electrostatic latent image, and the toner reattached to the surface of the image bearing member is used in the developing device. At the same time as collecting, the cleaning member is brought into pressure contact with the surface of the image bearing member, and at the pressure contact portion, the cleaning member is rotated in a direction in which the cleaning member moves in the same direction with respect to the image bearing member, and Recovery and recovery In the image forming apparatus for reattaching the toner to the surface of the image carrier, in order to cause the cleaning member to perform the filming removal operation of the image carrier, the cleaning member is pressed against the surface of the rotating image carrier, At the pressure contact portion, cleaning member drive control means for rotating the cleaning member in a direction in which the cleaning member moves in the opposite direction to the image carrier, and at the time of rotation,
A pressing force that switches the pressing force of the cleaning member against the image carrier so that the pressure contact force of the cleaning member against the image carrier is stronger than when the transfer residual toner is collected and when the collected toner is reattached to the image carrier. An image forming apparatus is proposed which has a switching means (claim 3).

Further, in order to achieve the same object, the present invention provides an image carrier which is rotationally driven, a latent image forming means for forming an electrostatic latent image on the carrier, and the electrostatic latent image as a toner. A developing device that visualizes an 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 transfer is temporarily collected, and then A cleaning member for reattaching the collected toner to a surface portion of the image bearing member that does not affect the formation of the next electrostatic latent image, and the toner reattached to the surface of the image bearing member is used in the developing device. At the same time as collecting, the cleaning member is brought into pressure contact with the surface of the image bearing member, and at the pressure contact portion, the cleaning member is rotated in a direction in which the cleaning member moves in the same direction with respect to the image bearing member, and Recovery and its recovery In an image forming apparatus for reattaching the cleaning member to the surface of the image carrier, the cleaning member is pressed against the surface of the rotating image carrier in order to cause the cleaning member to perform the filming removal operation of the image carrier. When the cleaning member is rotated, the absolute value of the difference between the linear velocities of the image carrier and the cleaning member at the pressure contact portion during rotation is the same when the transfer residual toner is collected and when the collected toner is reattached to the image carrier. An image forming apparatus is proposed which has a cleaning member drive control means for controlling the number of rotations of the cleaning member so as to be larger than the above (claim 4).

Further, in order to achieve the same object, the present invention further comprises an image carrier which is rotationally driven, a latent image forming means for forming an electrostatic latent image on the carrier, and the electrostatic latent image as a toner. A developing device that visualizes an 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 transfer is temporarily collected, and then A cleaning member for reattaching the collected toner to a surface portion of the image bearing member that does not affect the formation of the next electrostatic latent image, and the toner reattached to the surface of the image bearing member is used in the developing device. At the same time as collecting, the cleaning member is brought into pressure contact with the surface of the image bearing member, and at the pressure contact portion, the cleaning member is rotated in a direction in which the cleaning member moves in the same direction with respect to the image bearing member, and Recovery and recovery In the image forming apparatus for reattaching the toner to the surface of the image carrier, in order to cause the cleaning member to perform the filming removal operation of the image carrier, the cleaning member is pressed against the surface of the rotating image carrier, When the cleaning member is rotated, the absolute value of the difference between the linear velocities of the image carrier and the cleaning member at the pressure contact portion during rotation is the same when the transfer residual toner is collected and when the collected toner is reattached to the image carrier. Cleaning member drive control means for controlling the number of rotations of the cleaning member, and the pressing force of the cleaning member against the image carrier at the time of the rotation, when the transfer residual toner is collected and when the collected toner image is formed. And a pressing force switching means for switching the pressing force of the cleaning member with respect to the image carrier so that the pressure becomes stronger than when the toner is redeposited on the carrier. It proposes an image forming apparatus (claim 5).

[0017]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below in detail with reference to the drawings. First, the configuration and operation common to each specific example corresponding to each claim will be clarified.

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 section 3, an exposure scanning device (not shown) performs optical writing scanning using, for example, the light-modulated laser beam 11, so that a predetermined electrostatic latent image is formed on the surface of the photoconductor 1. Is formed. Photoconductor 1
The surface potential of the upper part A irradiated with the laser beam 11, that is, the surface potential of the electrostatic latent image is, for example, about −150 V, and the surface potential of the part B not irradiated with the laser beam 11, that is, the background potential of the background portion of the electrostatic latent image is almost It is maintained at -850V. As described above, in this example, the charging device including 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 including the photoconductor 1.

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

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 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 causes the photoconductor 1 to move. The toner image formed thereon 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.

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. A cleaning member including a cleaning roller 12 described below is provided.

The toner image on the photoconductor 1 is transferred to the transfer paper 16 by the transfer unit 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
When they reach the cleaning unit 14, they are temporarily collected by a cleaning roller 12 which is an example of a cleaning member.

The cleaning roller 12 has a core member 12a made of a rigid body, and a conductive or medium resistance elastic body 12b fixed on the surface of the core member 12a. In the illustrated example, the core member 12a. Is made of a round shaft-shaped conductive metal, and the elastic body 12b is made of a foamed material or solid rubber formed in a cylindrical shape concentric with the core member 12a. The cleaning roller 12 is housed in the cleaning case 17, and each end of the core member 12a is
The cleaning case 17 is rotatably supported on front and rear side walls, respectively. Such cleaning roller 12
Are located substantially parallel to the photoconductor 1 together with the developing roller 5, the charging roller 2, and the transfer roller 7.

Here, in FIG. 1, most of the toner T of the toner image directed from the developing unit 6 to the transfer unit 8 is a toner having a charging polarity at the time of development, that is, a negative polarity toner in this example. 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 adhered toner, that is, the transfer residual toner T ₁ is a toner in which positive and negative toners are mixed. 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 roller 12, when collecting the residual toner T ₁ of the the photosensitive member 1, the counterclockwise direction in FIG. 1 (arrow a direction), i.e., shown in the forward direction with respect to the rotation direction of the photosensitive member 1 It is rotationally driven by the drive control means which is not provided. The surface of the cleaning roller 12 is pressed against the photosensitive member 1 so that the surface of the cleaning roller 12 can be elastically deformed by the photosensitive member 1. As shown in FIG. 2, a nip region N is formed at this pressed portion. This nip area N becomes a cleaning area.

In the nip region N, the transfer residual toner T ₁ of both positive and negative polarities becomes a toner of the same polarity (negative polarity in this example) as the toner at the time of development while being in contact with the cleaning roller 12. It is frictionally charged. Transfer residual toner T ₁
However, the negative polarity, which is the charging polarity at the time of development, can be obtained. At the pressure contact portion between the cleaning roller 12 and the photoconductor 1, the rotation speed of the cleaning roller 12 is set so that the surface linear velocity of the two may be slightly different, and the cleaning roller 12 is rubbed against the surface of the photoconductor 1. It is desirable that the toner T ₁ be efficiently triboelectrically charged.

As described above, the cleaning roller 12 of this embodiment frictionally charges the transfer residual toner with the photosensitive member 1 and frictionally charges the toner so that the toner is aligned in the negative polarity which is the original polarity. It also performs the function of causing it. That is,
The cleaning member including the cleaning roller 12 is
When the transfer residual toner toward this includes the toner charged to the opposite polarity to the charge polarity of the toner at the time of development, the toner is charged so as to be aligned with the charge polarity (original polarity) of the toner at the time of development. The toner is triboelectrically charged. The elastic body 12b of the cleaning roller 12 is
The toner is composed of a charging-type charging material capable of frictionally charging the toner to its original polarity, which is negative in this example.

Returning to FIG. 1, the transfer residual toner T ₁ on the photosensitive member 1 after the toner image is transferred onto the recording medium made of the transfer paper 16
Is collected by a cleaning member composed of a cleaning roller 12 that rotates while being pressed against the photoconductor 1, and at the time of collection, the core member 12 of the cleaning roller 12 is collected.
A voltage having a polarity opposite to the charging polarity of the toner frictionally charged by the roller 12, that is, a positive voltage in this example, for example, +200 V, is applied to a by the voltage power source E ₄ .
Therefore, the residual toner after the 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 surface of the cleaning roller 12 to which the positive voltage is applied, and the residual toner of the roller 12 is transferred. It adheres to the surface and is temporarily collected by this roller. As a result, the surface of the photoconductor 1 is cleaned. As described above, the cleaning roller 12 rotating in contact with the photoconductor 1 has
Between the transfer residual toner T ₁ on the photosensitive member and the surface of the cleaning roller 12 to form an electric field that can be electrostatically attracted to the surface of the cleaning roller 12. Then, a positive polarity voltage is applied.

As described above, the cleaning roller 12
In the figure, the toner collected on the surface of the toner is indicated by reference numeral T ₂ . 3 to 11, the residual toner T ₁ of the the photosensitive member 1 is collected by the cleaning roller 12, then as described below, schematically showing an example of the operation for reattachment of the collected toner T ₂ to the photosensitive member 1 3 is a diagram showing the toner image on the photoconductor 1 in FIG.
The transfer residual toner T ₁ is transferred onto the surface of the cleaning roller 12 and is collected on the surface of the cleaning roller 12. As can be seen from FIG. 3, the surface portion of the photoconductor 1 that has been cleaned by the cleaning roller 12 is subjected to static elimination action by the static elimination lamp 13 which is an example of the static elimination device, and the surface potential thereof is lowered to the reference value. The charge eliminating lamp 13 continues to be turned on during the image forming operation. As shown in FIG. 3, the surface portion of the photoconductor that has been subjected to the static elimination is continuously charged by the charging roller 2, and the above-mentioned image forming operation is continued.

In this way, one sheet of toner image is formed on the photoconductor 1 during several rotations of the photoconductor 1, and this is continuously transferred to the transfer paper 16. The circumferential area on the photoreceptor 1 where such a toner image is formed is an image forming area. In FIG. 3, reference numeral X is attached to this image forming area, and reference numeral Y is attached to the front end in the direction of rotation of the photoreceptor.
Is attached. Similarly, FIG. 4 shows this image forming area X.
Reference numeral Z is attached to the rear end of the photosensitive member in the rotation direction.

When the leading edge Y of the image forming area X reaches the cleaning roller 12, the cleaning roller 1
The operation of collecting the transfer residual toner T _{1 on} the second transfer roller 2 starts. Further, in this example, the operation of collecting the transfer residual toner is continued until the trailing edge Z of the image forming area X reaches the cleaning roller 12. The portion of the image forming area X that has passed the cleaning roller 12 has already been cleaned by the cleaning roller.

As shown in FIG. 4, when the rear end Z of the image forming area X in the direction of rotation of the photosensitive member passes the charging roller 2, the charging roller 2 is separated from the surface of the photosensitive member 1 at this time. (See Figure 5). At the same time, the switch S ₁₀ shown in FIG. 1 is switched to turn off the voltage application to the charging roller 2.

[0037] When the image forming region trailing Z passes the developing roller 5 of the developing device 4 as shown in FIG. 5, is switched switch S ₁ shown in FIG. 1, the developing roller 5 is voltage source E ₂
A positive polarity voltage opposite to the charging polarity of the toner, for example, a voltage of +500 V is applied to the developing roller 5 so that the toner does not adhere to the photoconductor 1. Subsequently, as shown in FIG. 6, when the trailing edge Z of the image forming area passes the transfer portion 8, at this time, the voltage application to the transfer roller 7 is stopped. At this time, in this example, the transfer roller 7 is separated from the photoconductor 1 (see FIG. 7).

As described above, the cleaning roller 12 temporarily collects the transfer residual toner T ₁ on the photoconductor 1 after the toner image transfer, and then collects the collected toner T ₂ on the photoconductor 1. It is redeposited on the surface portion that does not affect the formation of the next electrostatic latent image. That is, when the trailing edge Z of the image forming area after the toner image is transferred onto the transfer paper 16 passes through the cleaning roller 12 as shown in FIG. 8, the switch S ₂ shown in FIG. 12 is connected to the voltage power source E ₅ , and the core member 12a of the cleaning roller 12 has the same negative polarity as the charging polarity of the toner frictionally charged by the cleaning roller 12;
For example, a voltage of -3000 V is applied. In this way, the toner on the cleaning roller 12 is provided between the cleaning roller 12 and the non-image forming area W (FIG. 8) on the surface of the photosensitive member on the rear side of the rear end Z of the image forming area in the rotation direction of the photosensitive member 1. An electric field is formed in the direction in which T ₂ is emitted toward the photoconductor 1.

Due to the electric field, as shown in FIG.
The toner T ₂ temporarily collected on the cleaning roller 12 is reattached to the non-image forming area W on the photoconductor 1 and returned. At this time also, the cleaning roller 12 is rotationally driven in the forward direction (counterclockwise in FIG. 1) with respect to the photoconductor 1. As shown in FIG. 9, the toner T ₃ 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 as shown in FIG. The developing device 4 is reached as shown. 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 T redeposited on the photoconductor 1 is applied.
₃ is electrostatically transferred to the developing roller 5 side and is collected in the developer in the developing device.

As described above, the cleaning roller 12
Removes the toner T ₂ temporarily collected on the surface of the photoreceptor 1.
The toner T ₃ redeposited on the image carrier composed of the toner T ₃ and redeposited on the surface of the image carrier is electrostatically collected in the developing device 4. The toner collected in the developing device 4 is reused in the developing device 4. In this way,
It is possible to eliminate the waste toner, and it is not necessary to provide a toner conveying pipe for returning the toner collected by the cleaning roller 12 to the developing device 4.

The toner T _2, which is collected by the cleaning roller 12, so re-adhering to the non-image forming region W of the rear end Z vicinity of the image forming area X on the photosensitive member 1, by the re-deposited toner T _3, above Not only the electrostatic latent image formed during the image forming operation but also the electrostatic latent image formed next is not affected. It is also possible to re-adhere the toner from the cleaning roller 12 to the rear portion of the image forming area X or the like. In short, the cleaning roller 12 is formed on the surface portion of the photoconductor 1 that does not affect the formation of the next latent image.
All that is required is to reattach the above-mentioned collected toner.

[0042] When the residual toner T ₁ of the the photosensitive member 1 is collected by the cleaning roller 12, when such end the collection of the transfer residual toner by the rotation of less than one rotation of the cleaning roller 12, during the recovery operation, always , Collected toner T
The transfer residual toner on the photoconductor 1 can be collected by the surface of the cleaning roller 12 to which ₂ does not adhere, and the collection efficiency can be improved. Further, from the time of collecting the transfer residual toner T ₁ of the the photosensitive member 1 by the cleaning roller 12 is also better at which to reattach the collected toner to the surface of the photosensitive member 1, accelerate the rotational speed of the cleaning roller 12,
It is advantageous that the collected toner is quickly returned to the surface of the photoconductor 1.

Further, as shown in FIG. 9, when the collected toner on the cleaning roller 12 is completely attached to the photoconductor 1 again, the cleaning roller 12 is again charged with the polarity of the toner during development. By applying a voltage of the opposite positive polarity and continuously driving the cleaning roller 12 in the forward direction with respect to the rotation direction of the photoconductor 1, a very small amount of toner that should not originally adhere to the photoconductor is obtained. However, it is preferable to control the cleaning roller 12 so that the toner is collected when the toner is attached.

When the image forming operation is continued,
When the next image forming area X1 shown in FIG. 9 and FIG. 10 is continuously subjected to the static elimination action by the static elimination lamp 13, and the leading end Y1 of the photoconductor rotating direction moves to the position of the charging roller 2, the charging roller 2 is exposed to light. By contacting the surface of the body 1 and charging the next image forming area X1 with a negative polarity, an electrostatic latent image is formed on the next image forming area X1 in exactly the same manner as described above. As shown, it is visualized as a toner image in the developing device 4. At this time, of course, the negative voltage is applied to the developing roller 5. When the leading edge Y1 of the image forming area reaches the transfer section 8, the transfer roller 7 is pressed against the photoconductor 1, and the leading edge of the next transfer paper 16 reaches the transfer section 8, and the next image forming area X1 is reached.
The toner image formed on the transfer paper 16 is transferred to the transfer paper 16.
The transfer residual toner at this time is temporarily collected by the cleaning roller 12 as described above, and the above-described operation is repeated. In this way, the image forming operation is repeated a predetermined number of times.

In the state shown in FIG. 9, neither the electrostatic latent image nor the toner image has been formed in the next image forming area X1. To be precise, the area X1 shown in FIG. It can be said that the area is to be the next image forming area. Further, in FIGS. 1 to 11, the toners T, T ₁ , T ₂ , and T ₃ on the photosensitive member 1 or the cleaning roller 12 are schematically enlarged.

As described above, by applying to the cleaning member a bias voltage having a polarity opposite to the charge polarity of the toner at the time of development, the transfer residual toner on the image carrier is electrostatically transferred to the cleaning member. It is possible,
As a result, 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. It can be electrostatically transferred to the body. As a result, the collected toner can be reattached to the image carrier, and the reattached toner can be collected in the developing device.

The above is the configuration and operation of the image forming apparatus common to each of first to fifth specific examples to be described later corresponding to claims 1 to 5. In such an image forming apparatus, the cleaning member including the cleaning roller 12 is used as the photosensitive member 1.
The surface of the image carrier composed of
In the nip region N) of the cleaning roller 12, the cleaning roller 12 is rotated in a direction in which the cleaning roller 12 moves in the same direction with respect to the photoconductor 1, that is, in the forward direction, to collect the transfer residual toner T _{1 and} the collected toner T _1. T ₂ photoconductor 1
Configured to redeposit on the surface of the. The photoconductor 1 rotates clockwise in FIG. 1, and the cleaning roller 12
Rotate counterclockwise and their directions of rotation are opposite to each other. According to this structure, the rubbing force applied from the photoconductor 1 to the surface of the cleaning roller 12 can be reduced, so that the life of the cleaning roller 12 can be extended.

On the other hand, when the above-described image forming operation is repeated, toner filming is formed on the surface of the photoconductor 1 with time. If this is left, the toner image formed on the photoconductor 1 is formed. Image quality deteriorates. As described above, when the transfer residual toner on the photoconductor is collected and the collected toner is reattached to the photoconductor, the cleaning roller 12 is
As shown by the chain line arrow b in FIG. 2, the toner filming on the photoconductor 1 can be removed by the cleaning roller 12 by rotating the photoconductor 1 in the counter direction with respect to the rotation direction. However, in the image forming apparatus of this embodiment, as described above, the cleaning roller 12 is rotated in the forward direction with respect to the rotation direction of the photoconductor 1 during the collection of the transfer residual toner and the reattachment of the toner. However, the toner filming on the photoconductor 1 cannot be reliably removed by the cleaning roller 12. Therefore, when the cleaning roller 12 is rotated in such a direction, conventionally, it is necessary to provide a dedicated filming removing member for removing the toner filming of the photoconductor 1, but in this case, the image is formed. The structure of the forming apparatus becomes complicated and its cost increases.

Based on the above recognition, the present invention is configured such that the filming of the image bearing member can be efficiently removed by the cleaning member without providing a dedicated filming removing member. The image forming apparatus of the first specific example corresponding to
In order to perform the filming removal operation of the image carrier composed of the photoconductor 1 by the cleaning member composed of the photosensitive member 1, the cleaning member is brought into pressure contact with the surface of the rotating image carrier, and the cleaning member carries the image carrier at the pressure contact portion. It has a cleaning member drive control means for rotating the cleaning member in a direction moving in the opposite direction to the body.

The image forming apparatus shown in FIG. 1 has, for example, a cleaning member including a drive motor (not shown), a control device for controlling the drive motor, and a transmission device for transmitting the rotation of the drive motor to the cleaning roller 12. Although the drive control means is provided, the drive control means causes the cleaning roller 12 to be in pressure contact with the surface of the photoconductor 1 rotating in the clockwise direction in FIG. Then, it is rotationally driven in the clockwise direction (direction of arrow b). As a result, the cleaning roller 12 executes the filming removal operation of the photoconductor 1.
At this time, the cleaning roller 12 rotates in the direction opposite to the moving direction of the photoconductor 1, that is, in the counter direction in the pressure contact portion (nip region N in FIG. 2) with the photoconductor 1, so that the cleaning roller 12 is formed on the photoconductor 1. Toner filming can be removed efficiently and surely. The filming removal operation as described above is continued while the photoconductor 1 makes at least one revolution, and the toner filming is completely removed over the entire circumference of the photoconductor 1.

As described above, since the filming of the photosensitive member 1 is removed by using the cleaning roller 12, a dedicated filming removing member is unnecessary, the structure of the image forming apparatus is complicated, and the cost thereof is increased. You can prevent malfunctions. Moreover, during the filming removal operation, the cleaning roller 12 rotates in the counter direction with respect to the rotation direction of the photoconductor 1, so that the toner filming of the photoconductor 1 can be efficiently removed. Further, at the time of collecting the transfer residual toner to the cleaning roller 12 and re-adhering the collected toner to the photoconductor 1, the cleaning roller 12 is forwardly moved with respect to the rotation direction of the photoconductor 1 at the pressing portion of both. Since it rotates to the end, it is possible to prevent the problem that the life of the cleaning roller is shortened. Since the filming removal operation is not always performed and its operation time is short, even if the cleaning roller 12 is rotated in the counter direction with respect to the rotation direction of the photoconductor 1, the life of the cleaning roller 12 is reduced. It is possible to suppress the problem that becomes short.

On the other hand, the image forming apparatus of the second specific example corresponding to claim 2 rotates so that the cleaning member composed of the cleaning roller 12 performs the filming removal operation of the image carrier composed of the photoconductor 1. A cleaning member drive control unit that rotates the cleaning member in a state where the cleaning member is in pressure contact with the surface of the image carrier, and the pressure contact force of the cleaning member with respect to the image carrier at the time of rotation, when the transfer residual toner is collected, It has a pressing force switching means for switching the pressing force of the cleaning member against the image carrier so that the collected toner becomes stronger than when the toner adheres to the image carrier again.

As described above, the image forming apparatus shown in FIG. 1 includes, for example, a drive motor (not shown), a control device for controlling the drive motor, and a transmission device for transmitting the rotation of the drive motor to the cleaning roller 12. It has a cleaning member drive control means consisting of, by this drive control means,
The cleaning roller 12 is rotationally driven at a time other than the image forming operation while being in pressure contact with the surface of the photoconductor 1 rotating clockwise as shown in FIG.
At this time, the cleaning roller 12 performs the filming removal operation of the photoconductor 1. At that time, the photoconductor 1 makes at least one rotation, and the toner filming is removed over the entire circumference thereof. In addition, in the second specific example, when the cleaning roller 12 rotates for the filming removal operation, the pressing force of the cleaning roller 12 against the photoconductor 1 is changed by the pressing force switching means to remove the transfer residual toner. This is stronger than when the toner is collected and when the collected toner is reattached to the photoconductor 1.

As described above, during the filming removal operation of the photoconductor 1 by the cleaning roller 12, the cleaning roller 12 is pressed against the photoconductor 1 with a large force, so that the toner filming of the photoconductor 1 can be efficiently removed. . Further, in this specific example, since the cleaning roller 12 is brought into contact with the photoconductor 1 with a large pressure, as long as there is a linear velocity difference between the surfaces of the two at the pressure contact portion of the two, the photoconductor 1
The rotation direction of the cleaning roller 12 with respect to the rotation direction may be counter direction or forward direction. The cleaning roller 12 may rotate in either direction of arrow a or b in FIG. 2 to perform the filming removal operation of the photoconductor 1.

12 to 14 show the cleaning roller 12 for the photosensitive member 1 when the cleaning roller 12 rotates to perform the filming removal operation of the photosensitive member 1.
An example of a pressing force switching unit that switches the pressing force of the cleaning roller 12 against the photoconductor 1 so that the pressure contact force of the toner is stronger than when the transfer residual toner is collected and when the collected toner is reattached to the photoconductor 1. Shows.

In FIG. 12, the cleaning roller 12
The cleaning case 17 for use in the main shaft of the image forming apparatus main body is not shown in the drawings.
It is rotatably supported by a tension spring 9 between the cleaning case 17 and the main body side plate.
It is multiplied by 8. The central axis of both pivots 19, that is, the swing axis of the cleaning case 17 extends parallel to the center of rotation of the cleaning roller 12 and the photoconductor 1 (FIG. 1).

The cam shaft 21 extending substantially parallel to the cleaning roller 12 is rotatably supported around a central axis thereof by a pair of image forming apparatus main body side plates (not shown) facing each other. A pair of pressing force switching cams 22 is fixedly mounted on the shaft, and one shaft end of the cam is connected to a motor 23.

As described above, when the transfer residual toner T ₁ on the photoconductor 1 shown in FIG. 1 is collected by the cleaning roller 12 and when the collected toner T ₂ is reattached to the photoconductor 1. At the time of image forming operation including, as shown in FIG. 13, on the back wall surface of the cleaning case 17 on the side opposite to the photoconductor 1, due to the elastic tension of the tension spring 18, the cam peripheral surface of the pressing force switching cam 22 is removed. Of these, the cam surface portion 22a is in pressure contact.

On the other hand, when the filming removal operation of the photoconductor 1 is executed at a time other than the image forming operation,
The motor 23 shown in FIG. 6 operates for a predetermined time, which causes the cam shaft 21 to rotate and the cam 22 to rotate clockwise from the position shown in FIG. 13 to the position shown in FIG. At this position, the cam surface portion 22b of the cam peripheral surface of the pressing force switching cam 22 comes into pressure contact with the back wall surface of the cleaning case 17. In this state, the cleaning roller 12 moves in the forward direction (arrow a) with respect to the rotation direction of the photoconductor 1.
Direction) or counter direction (arrow b direction) to scrape and remove the toner filming on the photoconductor 1.

The pressing force switching cam 22 has a cam surface portion 22.
Since b is set at a position farther from the cam surface portion 22a with respect to the axis of the cam shaft 21, the pressing force to the cleaning case 17 is due to the cam surface portion 22a coming into contact with the cleaning case 17. It is made stronger than the pressing force when it is present. That is, when the cleaning roller 12 performs the filming removal operation of the photoconductor 1, the cam 2 is removed more than when the transfer residual toner is collected and reattached to the photoconductor 1.
2 presses the cleaning case 17 with a large pressing force.

On the other hand, although the cleaning roller 12 is rotatable with respect to the cleaning case 17, it is arranged in a fixed position.
When the filming removal operation of the photoconductor is performed, the photoconductor is pressed against the photoconductor more strongly than when the transfer residual toner is collected and when the collected toner is reattached to the photoconductor 1. As described above, since the cleaning roller 12 is pressed against the photoconductor 1 with a strong force when removing the filming of the photoconductor, the toner filming of the photoconductor 1 can be efficiently removed.

When the filming removal operation of the photoconductor 1 is completed, the motor 23 shown in FIG. 12 operates in the opposite direction to that described above for a predetermined time, whereby the pressing force switching cam 22 shown in FIG. From the position shown in the same figure, it rotates counterclockwise in the figure to the position shown in FIG. 13 and stops. As a result, the cleaning roller 12 is pressed against the surface of the photoconductor 1 with a weak pressing force, and in this state, a normal image forming operation is performed. The residual transfer toner on the photoconductor 1 is collected by the cleaning roller 12, and the collected toner is reattached to the photoconductor 1.

That is, as shown in FIG. 13, the camshaft 2
Since the cam surface portion 22a located closer to the shaft center of 1 than the cam surface portion 22b is in pressure contact with the cleaning case 17, the pressure contact force of the cleaning roller 12 with respect to the photoconductor 1 is weaker than that during filming removal. Become. By setting the pressure contact force as described above, the load on the cleaning roller 12 is reduced, and it is possible to prevent the cleaning roller 12 from deteriorating for a long period of time and prevent the problem that the life of the cleaning roller 12 is shortened. When the filming of the photoconductor 1 is removed, the pressing force of the cleaning roller 12 to the photoconductor 1 is increased to improve the filming removal efficiency, and the pressure of the cleaning roller 12 to the photoconductor 1 is weakened during the normal image forming operation. That is, the life of the cleaning roller is prevented from being shortened.

The cam shaft 21, the pressing force switching cam 22 and the motor 23 shown in FIGS. 12 to 14 constitute an example of pressing force switching means for switching the pressing force of the cleaning member against the image carrier.

Note that, when the image forming apparatus is not performing the image forming operation or the filming removing operation, or when the image forming apparatus is inactive, such as when the image forming apparatus is turned off, the image forming apparatus shown in FIG. As shown, if the cleaning roller 12 is separated from the photoconductor 1, it is possible to more reliably prevent the cleaning roller 12 from being permanently deformed early.

For example, after the photosensitive member 1 is stopped at the end of the image forming operation, the motor 23 shown in FIG. 12 is operated to move the pressing force switching cam 22 from the position shown in FIG. When the cleaning case 17 shown in FIG. 13 is rotated to the position shown in FIG. 13, the cleaning case 17 shown in FIG. And
As shown in FIG. 15, the cleaning case 17 is stopped by the stopper pins 24 provided on the main body side plate, and the cleaning roller 12 is held at a position separated from the photoconductor 1. That is, when the cam surface portion 22c of the cam peripheral surface of the pressing force switching cam 22 comes to a position facing the cleaning case 17, the cleaning roller 12
Are completely separated from the photoconductor 1. The cam surface portion 22c is set at a position closest to the axial center of the cam shaft 21 on the cam peripheral surface. A configuration may be adopted in which the cleaning roller 12 is separated from the photoconductor 1 in a state where the cam surface portion 22c is in pressure contact with the cleaning case 17 without using the stopper pin 24.

Further, in order to start the image forming operation, the photosensitive member 1
15 is rotated, the motor 23 is operated to rotate the pressing force switching cam 22 from the position shown in FIG. 15 to the position shown in FIG. 13 to bring the cleaning roller 12 into pressure contact with the photoconductor 1.

The switching of the pressing force of the cleaning roller 12 with respect to the photosensitive member 1 and the separation of the roller from the photosensitive member may be performed by the displacement of the cleaning roller 12 itself instead of the displacement of the cleaning case 17. good. For example, the cleaning roller 12 shown in FIG.
Is provided in the cleaning case 17 so as to be movable in the radial direction of the photoconductor 1, that is, in the horizontal direction in the illustrated example, and is configured similarly to the pressing force switching cam 22 and is provided inside or outside the cleaning case. The core member 12a of the cleaning roller 12 may be pressed and displaced by a pressing force switching cam (not shown). In this case, the pressing force switching cam and the drive device for rotating the cam form the pressing force switching means.

By the way, in the above-described second specific example, when the cleaning roller 12 performs the filming removal operation of the photoconductor, the cleaning roller may be rotated in any direction. Similarly to the first specific example, if the cleaning roller 12 is rotated in the counter direction with respect to the rotation direction of the photoconductor 1, the cleaning roller 12 gives a large scraping force to the photoconductor 1, so that The filming removal efficiency can be further improved.

This is a third specific example corresponding to claim 3. That is, in the image forming apparatus of the third specific example, in order to cause the cleaning member composed of the cleaning roller 12 to perform the filming removal operation of the image carrier composed of the photoconductor 1, the cleaning member is mounted on the surface of the rotating image carrier. A cleaning member drive control unit that rotates the cleaning member in the direction in which the cleaning member moves in the opposite direction to the image carrier in the pressed contact state, and a cleaning member for the image carrier when the cleaning member rotates. A pressing force switching unit that switches the pressing force of the cleaning member with respect to the image bearing member is provided so that the pressure contact force becomes stronger than when the transfer residual toner is collected and when the collected toner is reattached to the image bearing member. There is. The image forming apparatus of the third specific example is
The cleaning member drive control means in the first specific example described above and the pressing force switching means in the second specific example are provided, and both of these means are connected together.
The operation of both of these configurations is achieved. The filming removal operation of the photoconductor 1 at this time is also performed by rotating the photoconductor 1 at least once.

Next, in the image forming apparatus of the fourth specific example corresponding to claim 4, the cleaning member composed of the cleaning roller 12 is rotated so as to perform the filming removal operation of the image carrier composed of the photoconductor 1. When the cleaning member is rotated while the cleaning member is pressed against the surface of the image carrier, the absolute value of the difference between the linear velocities of the image carrier and the cleaning member at the pressure contact portion is the residual toner after transfer. The cleaning member drive control means for controlling the rotation speed of the cleaning member is provided so as to be larger than when the toner is collected and when the collected toner is reattached to the image carrier.

The image forming apparatus of this specific example is the first
Through the cleaning member drive control means shown in the third specific example, when the cleaning roller 12 rotates to remove the filming of the photoconductor, the pressure contact portion (nip region N) between the photoconductor 1 and the cleaning roller 12 is removed. The rotational speed of the cleaning roller 12 is controlled so that the difference between the surface linear velocities of the two becomes larger than that during the collection of the transfer residual toner and the reattachment of the collected toner to the photoconductor, that is, during the normal image forming operation. It is configured to do. For example, when the cleaning roller 12 performs the filming removal operation of the photoconductor, the rotation speed of the cleaning roller 12 is made higher than that during the normal image forming operation. Also by this, the toner filming of the photoconductor can be efficiently removed. Moreover, during the normal image forming operation, the difference between the linear velocities of the surfaces of the cleaning roller 12 and the photosensitive member 1 at the pressure contact portion is not particularly large.
The deterioration of 2 is not accelerated.

Also in this specific example, when the filming of the photosensitive member is removed, the linear velocity difference in the pressure contact portion between the cleaning roller 12 and the photosensitive member 1 becomes large, and thus the toner filming can be efficiently removed. The rotation direction of the cleaning roller 12 at this time may be any direction, but if the cleaning roller 12 is rotated in the counter direction with respect to the rotation direction of the photoconductor 1 as in the first specific example, it is exposed. The effect of removing toner filming on the body can be further enhanced.

Next, in the image forming apparatus of the fifth specific example corresponding to the fifth aspect, the cleaning member composed of the cleaning roller 12 is rotated so as to perform the filming removal operation of the image carrier composed of the photoconductor 1. When the cleaning member is rotated while the cleaning member is pressed against the surface of the image carrier, the absolute value of the difference between the linear velocities of the image carrier and the cleaning member at the pressure contact portion is the residual toner after transfer. Of the cleaning member and the cleaning member drive control means for controlling the number of rotations of the cleaning member so as to be larger than that at the time of re-adhesion of the collected toner to the image carrier, and at the time of the rotation, the cleaning member drive unit The pressure of the cleaning member on the image carrier is adjusted so that the pressure contact force becomes stronger than when the residual toner after transfer is collected and when the collected toner is reattached to the image carrier. And a pressing force switching means for switching the pressure.

The image forming apparatus of this specific example is the same as the above-mentioned fourth one.
The cleaning drive control means in the above concrete example and the pressing force switching means in the second concrete example are provided. That is, when the cleaning roller 12 performs the filming removal operation on the photoconductor, the cleaning roller 12 rotates with respect to the photoconductor 1 at a linear velocity difference larger than that during the normal image forming operation, and the cleaning roller 12 also moves. Is pressed against the surface of the photoconductor 1 with a pressure larger than that during a normal image forming operation. With this configuration, the toner filming on the photoconductor can be removed more efficiently. During a normal image forming operation, the pressure contact force between the cleaning roller 12 and the photoconductor 1 and the linear velocity difference therebetween are kept small, so that the cleaning roller can be prevented from prematurely deteriorating. The rotation direction of the cleaning roller 12 in this specific example may be either direction,
It is preferable to rotate the photoconductor 1 in the counter direction with respect to the rotation direction of the photoconductor 1.

The filming removal operation of the above-described specific examples 4 and 5 is also performed by rotating the photoconductor 1 at least once.

In each of the specific examples described above, the filming removal operation of the photosensitive member by the cleaning roller 12 is performed at a suitable time when the image forming operation is not performed, but it is preferable that this filming removal operation be performed by the image forming apparatus. When the image forming operation is performed by using at least one of the time from when the power is turned on until the image forming apparatus rises to a state in which the image forming operation can be executed, or the time after the image forming operation is completed, the image forming operation is performed. It is advantageous that the filming removal operation can be performed without any interruption.

The filming removal operation may be performed every image forming operation, or may be performed each time the number of image formed sheets reaches a predetermined number.

As described above, in the image forming apparatus of this embodiment, the cleaning roller 12 for collecting the transfer residual toner on the photoconductor and reattaching the toner to the photoconductor 1 is
Since it has a toner filming removing function of the photoconductor 1, a dedicated filming removing member different from the cleaning roller 12 is not required, so that the structure of the image forming apparatus can be downsized and the structure can be simplified. And the cost can be reduced. Moreover, the cleaning roller 12 efficiently removes the toner filming on the photoconductor during the filming removal operation, and rotates in the forward direction with respect to the rotation direction of the photoconductor 1 during the normal image forming operation. The life of the roller 12 is not shortened.

The present invention is an image forming apparatus using not only a roller-shaped cleaning member but also an endless belt-shaped cleaning member, or an image formation using an endless belt-shaped member other than a drum-shaped image carrier. It can also be applied to devices. Further, the present invention can be applied to an image forming apparatus in which an intermediate transfer member is used as a recording medium, a toner image is transferred from the image carrier to the intermediate transfer member, and then the toner image is transferred to a transfer material. Further, according to the present invention, after the image bearing member is charged by the charging device, an electrostatic latent image is formed by a portion which is not irradiated with light at the time of image exposure on the surface of the image bearing member, and the latent image potential is charged to the opposite polarity. It can also be applied to a so-called positive / positive developing type image forming apparatus in which the generated toner is adhered to the electrostatic latent image to perform development.

[0081]

According to the image forming apparatus of the present invention, the transfer residual toner is collected by the cleaning member to the cleaning member, the collected toner is reattached to the image carrier, and then the reattached toner is attached. In the image forming apparatus that collects the toner in the developing device, it is not necessary to provide a dedicated member for removing the toner filming formed on the image carrier, and the structure of the image forming apparatus is simplified and its cost is reduced. Can be achieved. Moreover, at the time of removing the filming, the cleaning member is rotated in the counter direction with respect to the rotation direction of the image carrier, so that the toner filming of the image carrier can be efficiently removed. Further, since the cleaning member rotates in the forward direction with respect to the image carrier when the transfer residual toner on the image carrier is collected and when the collected toner is attached again, it is possible to prevent the cleaning member from being deteriorated early. .

Also in the image forming apparatus according to the second aspect of the present invention, since the cleaning member is pressed against the image carrier with a large force when removing the filming, the toner filming of the image carrier can be efficiently removed and the toner is recovered. Since the pressure contact force between the cleaning member and the image bearing member is weakened at the time of reattaching the cleaning member, it is possible to prevent the cleaning member from being deteriorated early.

According to the image forming apparatus of the third aspect,
The effects produced by the image forming apparatus according to the first and second aspects can be exhibited together.

According to the image forming apparatus of the fourth aspect,
Since the linear velocity difference between the cleaning member and the pressure contact portion of the image carrier becomes large during filming removal, the toner filming of the image carrier can be efficiently removed, and at the time of toner recovery and toner re-adhesion Since the difference between the linear velocities does not become particularly large, it is possible to prevent the problem that the cleaning member deteriorates early.

According to the image forming apparatus of the fifth aspect,
The effects produced by the image forming apparatus according to the second aspect and the fourth aspect can be exhibited together.

[Brief description of drawings]

FIG. 1 is a partial cross-sectional explanatory view of an image forming apparatus according to an exemplary embodiment of the present invention, in which the toner on a photoconductor and a cleaning roller is schematically illustrated and enlarged.

FIG. 2 is an enlarged schematic illustration of a toner and a frictional contact portion between the photosensitive member and the cleaning roller, for explaining that the charging polarities of the toner are made uniform.

FIG. 3 is an explanatory diagram illustrating a relative positional relationship between a charging roller, a developing roller, a transfer roller, a cleaning roller, and a photoconductor, and illustrating a state in which residual toner remaining on the photoconductor is collected by the cleaning roller. Is.

FIG. 4 is an explanatory diagram similar to FIG. 3, showing a state in which a rear end of the image forming area reaches a portion facing a charging roller.

FIG. 5 is an explanatory diagram similar to FIG. 3, showing a state in which the rear end of the image forming area reaches a portion facing the developing roller.

FIG. 6 is an explanatory view similar to FIG. 3, showing a state when the rear end of the image forming area reaches a portion facing the transfer roller.

FIG. 7 is an explanatory diagram similar to FIG. 3, showing a state when the rear end of the image forming area reaches a portion facing the cleaning roller.

FIG. 8 is an explanatory diagram similar to FIG. 3, showing a state in which the collected toner on the cleaning roller is reattached to the photoconductor.

FIG. 9 is an explanatory view similar to FIG. 3, showing how redeposited toner on the photoconductor is conveyed toward the developing device.

FIG. 10 is an explanatory view similar to FIG. 3, showing how the redeposited toner on the photoconductor is collected by the developing device.

FIG. 11 is an explanatory diagram similar to FIG. 3, showing a state when the leading end of the next image forming area reaches a portion facing the transfer roller.

FIG. 12 is a perspective view showing a means for switching the pressing force of the cleaning roller with respect to the photoconductor, together with a cleaning case provided with the cleaning roller.

FIG. 13 is a diagram showing a state of a pressing force switching cam during a normal image forming operation.

FIG. 14 is a diagram showing a state of a pressing force switching cam during a filming removing operation.

FIG. 15 is a partial cross-sectional view of the peripheral configuration portion of the cleaning roller separated from the photoconductor by the action of the pressing force switching cam.

[Explanation of symbols]

4 Developing device T ₁ toner T ₂ toner

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

Claims (5)

[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 the transfer residual toner on the image carrier after the toner image transfer is temporarily collected, and then the collected toner is collected on the image carrier. A cleaning member for reattaching to a surface portion that does not affect the formation of the next electrostatic latent image, and the toner reattached to the surface of the image carrier is collected by the developing device, and the cleaning member is attached to the surface of the image carrier. It is pressed against the surface, and at the pressed portion,
In an image forming apparatus that rotates the cleaning member in a direction in which the cleaning member moves in the same direction with respect to the image carrier, collects the transfer residual toner, and reattaches the collected toner to the surface of the image carrier. , In order to make the cleaning member perform the filming removal operation of the image bearing member, the cleaning member is pressed against the surface of the rotating image bearing member, and at the pressure contact portion, the cleaning member is in the opposite direction to the image bearing member. An image forming apparatus comprising: a cleaning member drive control means for rotating the cleaning member in a direction in which the cleaning member is moved to the direction. 2. An image carrier that is rotationally driven, 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 the transfer residual toner on the image carrier after the toner image transfer is temporarily collected, and then the collected toner is collected on the image carrier. A cleaning member for reattaching to a surface portion that does not affect the formation of the next electrostatic latent image, and the toner reattached to the surface of the image carrier is collected by the developing device, and the cleaning member is attached to the surface of the image carrier. It is pressed against the surface, and at the pressed portion,
In an image forming apparatus that rotates the cleaning member in a direction in which the cleaning member moves in the same direction with respect to the image carrier, collects the transfer residual toner, and reattaches the collected toner to the surface of the image carrier. In order to cause the cleaning member to perform the filming removal operation of the image carrier, the cleaning member drive control means for rotating the cleaning member in a state where the cleaning member is pressed against the surface of the rotating image carrier, and at the time of the rotation, A pressing force that switches the pressing force of the cleaning member against the image carrier so that the pressure contact force of the cleaning member against the image carrier is stronger than when the transfer residual toner is collected and when the collected toner is reattached to the image carrier. An image forming apparatus comprising: a switching unit. 3. 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 the transfer residual toner on the image carrier after the toner image transfer is temporarily collected, and then the collected toner is collected on the image carrier. A cleaning member for reattaching to a surface portion that does not affect the formation of the next electrostatic latent image, the toner reattached to the surface of the image carrier is collected by the developing device, and the cleaning member is attached to the surface of the image carrier. It is pressed against the surface, and at the pressed portion,
In an image forming apparatus that rotates the cleaning member in a direction in which the cleaning member moves in the same direction with respect to the image carrier, collects the transfer residual toner, and re-attaches the collected toner to the surface of the image carrier. , In order to make the cleaning member perform the filming removal operation of the image bearing member, the cleaning member is pressed against the surface of the rotating image bearing member, and at the pressure contact portion, the cleaning member is in the opposite direction to the image bearing member. The cleaning member drive control means for rotating the cleaning member in the direction of moving to the direction, and the pressure contact force of the cleaning member against the image carrier at the time of its rotation, when the transfer residual toner is collected, and the collected toner is re-adhered to the image carrier. And a pressing force switching means for switching the pressing force of the cleaning member against the image carrier so as to be stronger than the time. Image forming apparatus. 4. An image carrier that is rotationally driven, 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 the transfer residual toner on the image carrier after the toner image transfer is temporarily collected, and then the collected toner is collected on the image carrier. A cleaning member for reattaching to a surface portion that does not affect the formation of the next electrostatic latent image, and the toner reattached to the surface of the image carrier is collected by the developing device, and the cleaning member is attached to the surface of the image carrier. It is pressed against the surface, and at the pressed portion,
In an image forming apparatus that rotates the cleaning member in a direction in which the cleaning member moves in the same direction with respect to the image carrier, collects the transfer residual toner, and reattaches the collected toner to the surface of the image carrier. In order to cause the cleaning member to perform the filming removal operation of the image carrier, the cleaning member is rotated while the cleaning member is pressed against the surface of the rotating image carrier, and at the time of rotation, the image carrier and the cleaning member are rotated. The number of rotations of the cleaning member is controlled so that the absolute value of the difference between the linear velocities of the two at the pressure contact portion is larger than when the transfer residual toner is collected and when the collected toner is reattached to the image carrier. An image forming apparatus having a cleaning member drive control means. 5. An image carrier that is rotationally driven, 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 the transfer residual toner on the image carrier after the toner image transfer is temporarily collected, and then the collected toner is collected on the image carrier. A cleaning member for reattaching to a surface portion that does not affect the formation of the next electrostatic latent image, and the toner reattached to the surface of the image carrier is collected by the developing device, and the cleaning member is attached to the surface of the image carrier. It is pressed against the surface, and at the pressed portion,
In an image forming apparatus that rotates the cleaning member in a direction in which the cleaning member moves in the same direction with respect to the image carrier, collects the transfer residual toner, and reattaches the collected toner to the surface of the image carrier. In order to cause the cleaning member to perform the filming removal operation of the image carrier, the cleaning member is rotated while the cleaning member is pressed against the surface of the rotating image carrier, and at the time of rotation, the image carrier and the cleaning member are rotated. The number of rotations of the cleaning member is controlled so that the absolute value of the difference between the linear velocities of the two at the pressure contact portion is larger than when the transfer residual toner is collected and when the collected toner is reattached to the image carrier. Cleaning member drive control means and at the time of its rotation,
A pressing force that switches the pressing force of the cleaning member against the image carrier so that the pressure contact force of the cleaning member against the image carrier is stronger than when the transfer residual toner is collected and when the collected toner is reattached to the image carrier. An image forming apparatus comprising: a switching unit.