JP3324723B2 - Image forming device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for forming an electrostatic latent image on an image carrier by uniformly charging a rotatably driven image carrier by charging means and performing exposure scanning on the charged surface. The electrostatic latent image is visualized as a toner image by a developing device, the toner image is transferred to a recording medium by a transfer unit, and the toner remaining on the image carrier is transferred to the cleaning member after the transfer of the toner image. The present invention relates to an image forming apparatus that collects and cleans the surface of an image carrier.

[0002]

2. Description of the Related Art In an image forming apparatus of the above-mentioned type configured as a copying machine, a printer, a facsimile, or a multifunction peripheral thereof, an image carrier is used repeatedly. It is necessary to remove and collect the residual toner by a cleaning member. For this reason, various cleaning devices for cleaning the image carrier have been conventionally proposed and put into practical use, but the conventional cleaning device generally stores toner collected from the image carrier in a waste toner tank or the like, It is configured to discard this.

In recent years, in this type of image forming apparatus employing an electrophotographic process, it has been attempted to further reduce the cost and further reduce the amount of discarded toner as part of environmental measures. Requested.

In view of the above, for example, when the transfer rate of a toner image from an image carrier to a recording medium is set to 100% to eliminate residual toner after transfer, a so-called cleanerless method 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, toner remaining on the surface of the image carrier after transfer of the toner image (hereinafter referred to as “transfer residual toner” as necessary) is collected by attaching it to a cleaning member. A method has been proposed in which the collected toner is re-adhered to the image carrier, collected by the developing device, and the collected toner is reused in the developing device (for example, see Japanese Patent Publication No. Sho 61-30274). After the transfer of the toner image, the toner remaining on the image carrier is temporarily collected by a cleaning member, and then the collected toner is re-used on a surface portion of the image carrier that does not affect the formation of the next latent image. The adhered and then re-adhered toner is collected by the developing device. This eliminates the need for a means for transferring the scraped toner to a waste toner tank or the like, so that the cost of the image forming apparatus can be reduced, and the toner can be recycled, so that waste toner can be eliminated. .

In the image forming apparatus having such a configuration, if paper dust is mixed in the toner collected in the developing device,
Streak-like image omission on the image caused by the paper dust occurs, and the image quality is easily deteriorated. In a conventional image forming apparatus of this type, since such a measure for removing paper dust is not taken, a streak-like image dropout occurs on an image, and the image quality is easily deteriorated.

[0007]

SUMMARY OF THE INVENTION An object of the present invention is to provide an image forming apparatus in which an untransferred toner collected by a cleaning member is re-adhered to an image carrier and the re-adhered toner is collected by a developing device. It is an object of the present invention to provide an image forming apparatus which removes paper dust mixed in the toner collected in the above, and eliminates a problem that image quality deteriorates.

[0008]

According to the present invention, in order to achieve the above object, an image carrier which is driven to rotate is uniformly charged by a charging means, and the charged surface is exposed and scanned. An electrostatic latent image is formed thereon, the electrostatic latent image is visualized as a toner image by a developing device, and the toner image is transferred to a recording medium by a transfer unit. The toner remaining on the image carrier was temporarily collected by a cleaning member, and then the collected toner was re-adhered to a surface portion of the image carrier that did not affect the formation of the next latent image, and further re-adhered. In an image forming apparatus that collects toner with a developing device, a paper dust removing unit that removes paper dust mixed in the toner collected by the developing device is provided in the developing device. With air release openings A depressurizing filter provided in the opening to allow air to flow out of the developing device main body and prevent the passage of the developer out of the developing device main body. An image forming apparatus is proposed in which a powder removing unit is integrally and detachably attached to a developing device main body.

[0009]

[0010]

Further, in the above configuration, it is advantageous that the depressurizing filter, the paper dust removing means, and the toner supply container are integrally and detachably mounted on the developing device main body.

[0012]

Further, in the above configuration, it is advantageous that the paper dust removing means comprises a paper dust removing filter, and the filter is provided in a developer circulation path in the developing device main body.

[0014]

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 sectional view showing a schematic configuration of an image forming apparatus according to an embodiment of the present invention. In FIG. 1, a drum-shaped photoconductor 1 as an example of a configuration of an image carrier is rotationally driven clockwise in FIG. 1 by a driving unit (not shown). , The surface of the photoconductor 1 is uniformly charged to a predetermined polarity. In this embodiment, the charging roller 2 is connected to a negative (minus) polarity voltage source E ₁₀ of, between which contacts rotating with the photosensitive member 1 uniformly charges the surface of the photosensitive member 1 to a negative polarity. By the action of the charging roller 2, the surface of the photoconductor 1 is charged to, for example, -850V. As a charging unit for uniformly charging the photoreceptor 1, a charging device disposed apart from the photoreceptor, such as a corona discharger, may be used.

Next, in the exposing section 3, exposure scanning, for example, optical writing scanning with the light-modulated laser light 11, is performed, so that a predetermined electrostatic latent image is formed on the surface of the photoreceptor 1. Photoreceptor 1 that is driven to rotate during image formation
Exposure scanning is performed on the charged surface of
An electrostatic latent image is formed thereon. The surface potential of the portion A irradiated with the laser light forming the electrostatic latent image is, for example, about -150 V, and the surface potential of the portion B not irradiated with the laser light is maintained at approximately -850 V.

The developing device 4 includes a developing roller 5, which is an example of a developer carrying member disposed opposite the photosensitive member 1, and a pair of stirring paddles 10A, 10B, which form a main body of the developing device. Each is provided in the developing casing 9 and is rotatably supported by the casing 9. The voltage source E ₁ to the developing roller 5 of this, for example, a voltage of about -600V is applied. 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 exemplified here, a two-component developer D having a toner and a carrier is used, and the developer D is contained in a developing casing 9. Then, by the rotation of the stirring paddles 10A and 10B, the toner is charged to a predetermined polarity due to friction with the carrier, in this example, the same polarity as the charging polarity of the photoreceptor 1, that is, to the negative polarity. In this example, the charge polarity of the toner during development is negative.

The developing roller 5 is driven to rotate in the clockwise direction in the figure, and the developer carried on the peripheral surface thereof is conveyed in the rotating direction of the developing roller 5 and is fixed with respect to the roller 5 by a predetermined amount. Is scraped off by the developer regulating member 15 opposed to the gap. The developer, the transport amount of which is regulated by the developer regulating member 15, is conveyed toward the developing unit 6, where the toner in the developer electrostatically forms an electrostatic latent image on the photoconductor 1. It is attracted and adheres to that part. That is, the toner charged to the same negative polarity as the charged polarity of the photoreceptor adheres to the surface portion A of the photoreceptor irradiated with the laser beam, and the electrostatic latent image is visualized as a toner image. Thus, the electrostatic latent image is visualized as a toner image by the developing device 4. In the image forming apparatus of this embodiment, a reversal developing method (negative / positive developing method) is employed.

A transfer charging roller 7, which is an example of a transfer charging unit, is provided below the photosensitive member 1. The transfer charging roller 7 rotates in a forward direction with respect to the rotation direction of the photoconductor 1, and moves toward a transfer unit 8 between the transfer charging roller 7 and the photoconductor 1 with which the transfer charging roller 7 contacts, and a recording medium made of transfer paper is formed. P is fed in the direction of the arrow, and the toner image formed on the photoconductor 1 is transferred to the recording medium P by the function of the transfer charging roller 7. That is, the power source E _3, the transfer charging roller 7, opposite to the charging polarity of the toner on the photosensitive member 1 positive (plus) polarity voltage, e.g., +95
A voltage of 0 V is applied, and at this time, the negative toner T on the photoreceptor 1 (which is schematically shown large) is electrostatically attracted to the recording medium P side, and Attaches to P. In this way, the toner image on the photoconductor 1 is transferred to the recording medium P by the transfer unit 8.

The recording medium P to which the toner image has been transferred is separated from the photosensitive member 1 by a separating device (not shown) and sent to a fixing device (not shown) where the toner image on the recording medium is fixed. .

As described above, the toner image on the photoreceptor 1 is transferred to the recording medium P by the transfer unit 8. After the transfer of the toner image, the toner that has not contributed to the transfer is transferred to the surface of the photoreceptor 1. There is residual adhesion. When the transfer residual toner reaches the cleaning unit 14, it is temporarily collected by the cleaning roller 12, which is an example of a cleaning member.

Here, in FIG. 1, most of the toner T of the toner image traveling from the developing section 6 to the transfer section 8 is a negative toner. On the other hand, since a positive voltage is applied to the transfer charging roller 7 during the transfer of the toner image, the toner remaining on the photoconductor 1 after the transfer of the toner image, that is, the transfer residual toner T ′ The toner is a mixture of a negative toner and a negative toner. The transfer residual toner is transferred to the cleaning unit 14 in a state where toners of both positive and negative polarities are mixed.

The cleaning roller 12 is made of, for example, a foam having a medium specific resistivity having a medium resistance value. It is driven and rotates while rubbing against the surface of the photoconductor 1. The cleaning roller 12 has its own surface portion,
The photosensitive member 1 is elastically deformed by the photosensitive member 1.
As shown in FIG. 2, a nip region N is formed in this pressed portion. This nip area N is a cleaning area.

In the nip area N, the transfer residual toner T 'having both positive and negative polarities is brought into contact with the cleaning roller 12 so as to be a toner having the same polarity (in this example, negative polarity) as the toner after development. It is triboelectrically charged. Transfer residual toner T '
Is adjusted to the negative polarity, which is the charging polarity during development.

As described above, the cleaning roller 12
It also performs a function of frictionally charging the transfer residual toner with the photoreceptor 1 and frictionally charging the toner so that the toner has the original polarity of negative polarity. That is,
When the transfer residual toner toward the cleaning member including the cleaning roller 12 includes a toner charged to the opposite polarity to the charge polarity of the toner during development, the toner is charged polarity (original polarity) of the toner during development.
The toner is frictionally charged so that the toners are aligned. The cleaning roller 12 is made of a charging material of a charging series capable of frictionally charging the toner with its original polarity, in this example, negative polarity.

Returning to FIG. 1, a voltage opposite to the charging polarity of the toner triboelectrically charged by this, that is, a positive voltage in this example, for example, a voltage of +200 V, is applied to the cleaning roller 12 by the voltage power supply E _4. You. Here, the residual toner after the transfer of the toner image that has passed through the transfer unit 8, that is,
The transfer residual toner T ′ is electrostatically attracted to the cleaning roller 12 to which the positive voltage is applied, and
2 and is temporarily collected by this roller. As a result, the surface of the photoconductor 1 is cleaned. The cleaning roller 12 that rotates in contact with the photoconductor 1 has an electric field between the photoconductor 1 and the transfer residual toner on the photoconductor that can be electrostatically attracted toward the cleaning roller 12. The voltage as described above is applied so that is formed.

The surface of the photosensitive member 1 has a cleaning roller 12
After the cleaning, the charge is removed by the charge removing lamp 13 which is an example of the charge removing device, and the above-described image forming operation is continued. In this way, one toner image is formed on the photoconductor 1 and is transferred to the recording medium P. The photoconductor 1 on which the toner image is formed is formed.
The upper area is the image forming area, and the area thereafter is the non-image forming area. When the rear end of the image forming area in the photoconductor rotation direction passes through the charging roller 2, the charging roller 2 is separated from the surface of the photoconductor 1 at this time. At the same time, the switch S ₁₀ is switched, the application of a voltage to the charging roller 2 is turned off.

[0029] When the image forming region trailing described above passes the developing roller 5 of the developing device 4, the switch S ₁ is switched, the developing roller 5 is connected towards the voltage source E _2, in its developing roller 5, In order to prevent the toner from adhering to the photoconductor 1, a positive voltage opposite to the charging polarity of the toner, for example, +
A voltage of 500 V is applied. When the rear end of the image forming area passes through the transfer section 8, the application of the voltage to the transfer charging roller 7 is stopped at this time.

Furthermore, when the image forming region trailing after the toner image is transferred onto the recording medium has passed the cleaning roller 12, the switch S ₂ is switched, the cleaning roller 12 is connected towards the voltage source E ₅ A voltage of, for example, -3000 V having the same negative polarity as the charge polarity of the toner frictionally charged by the cleaning roller 12 is applied to the cleaning roller 12. That is, an electric field is generated between the rotating cleaning roller 12 and the non-image forming area of the photoconductor 1 in a direction in which the toner on the cleaning roller 12 is discharged toward the photoconductor 1.

By the electric field, the toner temporarily collected on the cleaning roller 12 is reattached to the non-image forming area on the photosensitive member 1 and returned. The toner re-adhering to the photoconductor 1 passes below the charge removing lamp 13 and the charging roller 2 distant from the photoconductor 1 due to the subsequent rotation of the photoconductor 1, and reaches the developing device 4. At this time, since the positive polarity voltage opposite to the charging polarity of the toner is applied to the developing roller 5 as described above, the negative polarity toner re-adhered to the photoreceptor 1 is removed from the developing roller 5. 5 and is collected in the developer in the developing device.

When the image forming operation is performed continuously,
The above operation is repeated a predetermined number of times.

As described above, in the image forming apparatus of this embodiment, the toner remaining on the photosensitive member 1 after the transfer of the toner image is temporarily collected by the cleaning member including the cleaning roller 12, and then the collected toner is collected. Is re-adhered to the image carrier made of the photoreceptor 1, and the re-adhered toner is electrostatically collected by the developing device 4. The toner collected in the developing device 4 is reused in the developing device 4. In this way, waste toner can be eliminated, and there is no need to provide a toner conveying pipe for returning the toner collected by the cleaning roller to the developing device.

By applying a bias voltage having a polarity opposite to the charging polarity of the toner during development to the cleaning member, the transfer residual toner on the image carrier can be electrostatically transferred to the cleaning member. Thereby, the transfer residual toner can be collected toward the cleaning member. After the collection, the polarity of the bias voltage applied to the cleaning member is switched, and a bias voltage having the same polarity as the charging polarity of the collected toner is applied to the cleaning member. Thus, the collected toner can be re-attached to the image carrier, and the re-attached toner can be collected in the developing device.

Further, the toner collected by the cleaning roller 12 adheres again to the non-image forming area near the rear end of the image forming area on the photoreceptor 1. Of the electrostatic latent image,
The next formed electrostatic latent image is not affected. The collected toner is re-attached to the surface of the photoreceptor 1 which does not affect the formation of the next latent image. In any of the electrostatic latent images, the toner from the cleaning roller 12 is reattached to the surface of the photoreceptor which is formed on the photoreceptor without being disturbed by the reattached toner. It is also possible to adopt a configuration in which the toner from the cleaning roller 12 is re-attached to the rear part in the image forming area.

Further, in the image forming apparatus of this embodiment, when the transfer residual toner T 'on the photosensitive member is collected by the cleaning roller 12 as shown in FIG. The rotation direction of the cleaning roller 12 is set so that the cleaning roller 12 moves in the opposite direction (counter direction) to the moving direction of the photoconductor 1 in the nip region N in pressure contact with the photoconductor 1. The operation of recovering the transfer residual toner is completed by the rotation of less than one rotation of twelve. In the nip area N, the toner T ′
Is charged by contact with the cleaning roller 12 so as to be aligned with a predetermined charging polarity during development. However, it is difficult to charge all the toner T 'to this polarity. Some toners have an amount of almost zero volts.

Therefore, if the cleaning roller 12
Assuming that the cleaning roller 12 is rotated in the nip region N with the photoconductor 1 in a direction in which the two move in the same direction, as indicated by a chain line arrow in FIG. The collected toner T ″ is present on the roller 12. If the toner T ″ remains positively charged or its charge amount is zero, the cleaning roller 12 has the same polarity as the collected toner T ″. Since the positive voltage is applied, the positive polarity toner T ″ is electrostatically attracted toward the photoconductor 1 and adheres to the photoconductor surface. In this case, the cleaning of the photoconductor 1 is performed. A defect occurs, and the subsequently formed toner image becomes soiled.

In order to eliminate such a problem, in this embodiment, the rotation directions of the cleaning roller 12 and the photosensitive member 1 are set so that the cleaning roller 12 rotates in the counter direction with respect to the rotation direction of the photosensitive member 1 as described above. At this time, if the toner is recovered from the photoreceptor 1 by rotating the cleaning roller 12 by one or more rotations, if the toner T ″ charged to the positive polarity is present in the toner recovered by the cleaning roller 12, this is detected. In this case, the toner collecting operation from the photosensitive member 1 to the cleaning roller 12 is completed while the cleaning roller 12 is rotating less than one rotation. Let me.

When the collected toner on the cleaning roller 12 is re-attached to the photosensitive member 1, the cleaning roller 1
2 may be rotated in any direction. In this embodiment, the cleaning roller 1 is rotated in the nip region N with the photoconductor 1.
The rotation direction of the cleaning roller 12 is controlled so that the photoconductor 2 and the photoreceptor 1 rotate in the same direction (the direction of the dashed arrow in FIG. 2), and the rotation speed is higher than that during toner collection.
The toner is re-attached to the photoconductor 1 in a short time.

Here, since the recording medium P made of transfer paper comes into contact with the surface of the photoreceptor 1 in the transfer section 8, the transfer residual toner is mixed with paper dust 16 (for convenience, together with the transfer residual toner T 'in FIG. 1). (Shown schematically in an enlarged scale). Therefore, when the toner is collected from the photoconductor 1 to the cleaning roller 12, the paper dust 16 also adheres to the cleaning roller 12 together with the toner. The paper dust adhered to the cleaning roller 12 is further adhered to the photoconductor 1 together with the toner, and is collected on the developing roller 5 of the developing device 4.
Therefore, if left unattended, paper dust will be mixed into the developer D in the developing casing 9.

If paper powder is mixed in the developer D,
When the developer D is carried to the portion of the developer regulating member 15 while being carried on the developing roller 5, a gap (for example, about 0.5 mm) between the regulating member 15 and the developing roller 5 is provided. And the amount of the developer becomes extremely small along the circumferential direction of the developing roller 5, thereby causing streak-like image omission on the image formed on the photoreceptor 1 (so-called, , White spots) and image quality deteriorates. Similarly, when a one-component developer having no carrier is used as the developer, if paper powder is mixed in the one-component toner, a streak is formed on the toner image on the photoconductor, and the image quality is deteriorated.

Therefore, in the image forming apparatus of this embodiment,
The developing device 4 is provided with paper dust removing means for removing paper dust mixed in the toner collected by the developing device 4.

In FIG. 1, reference numeral 17 denotes a paper dust removing filter which is an example of the configuration of the paper dust removing means. When the above-described developing operation is performed in the developing device 4, the developer D in the developing casing 9 is supplied to the developing roller 5, carried and conveyed, and used for visualizing the electrostatic latent image on the photoconductor 1. After that, the front end is scraped off from the developing roller 5 by a scraper 18 facing the peripheral surface of the developing roller 5, dropped into the regions of the stirring paddles 10A and 10B, and mixed by the paddle. As described above, the developer circulates in the developing casing 9 constituting the developing device main body, and a paper dust removing unit including the paper dust removing filter 17 is provided in the developer circulation path. In the example of FIG.
A paper dust removal filter 17 is disposed in a path of the developer falling from the scraper 18. The paper dust removal filter 17 is a filter having a mesh of a size that allows the passage of the developer but prohibits the passage of the paper dust.
The paper dust mixed in the reattached toner is removed from the developer by the filter 17 as follows.

When the toner re-adhering to the photosensitive member 1 from the cleaning roller 12 reaches the area of the developing device 4, first,
The toner is electrostatically attracted to the developing roller 5 and then conveyed in the rotation direction of the roller 5 together with the developer on the developing roller 5. The transported toner and the developer on the developing roller 5 are scraped by the scraper 18 to the developing roller 5.
Scraped from. Next, the scraped developer passes through the mesh of the paper dust removing filter 17 and falls downward, but the paper dust is left on the filter 17. The developer that has passed through the filter 17 is carried on the developing roller 5 while being stirred by both stirring paddles 10A and 10B, and is conveyed to the developing unit 6 while being regulated by the developer regulating member 15, where the electrostatic latent image is formed. Is subjected to development again during the developing operation.

As described above, the paper dust and the developer dropped from the scraper 18 are separated from each other by the paper dust removal filter 17, only the developer passes through the paper dust removal filter 17, and the paper dust 16 is filtered by the filter 17. Since it remains on the top, it is possible to prevent paper dust from being mixed into the developer used for development. Paper dust is less likely to be mixed with the developer D in the developing casing 9, and the paper dust can be prevented from clogging the gap between the developer regulating member 15 and the developing roller 5. It is possible to prevent the occurrence of white stripes or the like on the image, and to prevent the image quality from deteriorating. The paper dust removal filter 17 can also remove foreign matters other than paper dust mixed in the developer.

When the paper dust removing means is constituted by the paper dust removing filter 17 as described above, the structure can be simplified,
The cost can be reduced. By providing the paper dust removing filter 17 in the developer circulation path in the developing device main body composed of the developing casing 9, the paper dust mixed in the reattached toner can be reliably removed.

In the illustrated image forming apparatus, a paper dust removing means comprising a paper dust removing filter 17 is detachably attached to a developing device main body comprising a developing casing 9. That is, the paper dust removing filter 17 is assembled to the unit plate 25, and the plate 25 is detachably fixed to the developing casing 9 by a fixing member including screws 26.

According to this configuration, when the paper dust removing filter 17 is clogged by the paper dust, the unit plate 25 is removed from the developing casing 9 together with the paper dust removing filter 17 by removing the screw 26, and another A new paper dust filter installed on the unit plate,
Alternatively, the cleaned paper dust removing filter 17 assembled to the unit plate 25 can be fixed to the developing casing 9 with screws 26 for use.

At this time, in the illustrated image forming apparatus, as described below, the paper dust removing filter 17 is configured to be exchangeable together with other elements.

In this type of image forming apparatus, the internal pressure in the developing casing 9 is increased by the inflow of air into the developing casing 9 based on the rotational force of a rotating element such as the developing roller 5 provided in the developing casing 9. It is easy to rise.
When the internal pressure increases, the toner is easily scattered outside the developing casing 9. Therefore, this type of developing device is generally
The developing device has an air release opening 19 for preventing the internal pressure of the developing device from rising. As a result, an increase in the internal pressure of the developing casing 9 constituting the developing device main body can be prevented. However, if the opening 19 is left open, the toner in the developing casing 9 scatters outside the developing casing including the paper powder. Therefore, the illustrated developing device 4
Has a depressurizing filter 20 provided in the opening 19 to allow the air to flow out of the developing device main body composed of the developing casing 9 and to prevent the passage of the developer outside the developing device main body. I have. Thereby, the toner including the paper powder
Scattering to the outside of the developing device main body can be prevented.

On the other hand, in the developing device 4 illustrated in the figure, as described above, the two-component developer D having the toner and the carrier is used, and the toner is appropriately supplied to the developer. It is supposed to be. 1 is a container for supplying toner.
May be called a toner supply cartridge. From this toner replenishing container 22, a replenishing toner (not shown) is put into a toner replenishing chamber 23 secured in one area in the developing casing 9. When a decrease in the toner concentration of the two-component developer in the developing casing 9 is detected, the rotation of the toner replenishing roller 24 provided in the toner replenishing chamber 23 causes the toner in the developer in the developing casing 9 to rotate. Will be replenished. When the toner in the toner replenishing chamber 23 runs out or the amount of remaining toner is reduced, the toner replenishing container 22 is replaced with a new toner replenishing container containing toner, and the toner replenishing chamber 23 Is supplied with toner.

Here, the pressure release filter 20 described above,
Paper dust removal filter 17 which is one configuration example of paper dust removal means
Is integrally and detachably attached to a developing casing 9 which is a developing device main body. That is,
The depressurizing filter 20 is also attached to the unit plate 25 described above, and both filters 17 and 20 are integrally assembled, and an opening 19 is formed in the plate 25. According to such a configuration, since both filters 17 and 18 can be replaced simultaneously by attaching and detaching the screw 26, the frequency of replacement can be reduced and the number of maintenance operations can be reduced as compared with a case where these filters are replaced separately. .

Further, the paper dust removing filter 17, which is an example of the paper dust removing means, and the above-described toner supply container 22 are connected to the developing device main body comprising the developing casing 9.
It can also be attached integrally and detachably. That is, the toner supply container 22 is attached to the unit plate 25 described above, and the paper dust removal filter 17 and the toner supply container 22 are integrally assembled. According to this configuration, when the toner supply container 22 is replaced, the paper dust removing filter 17 can be replaced at the same time.
A dedicated maintenance operation for the paper dust removing filter 17 can be omitted. In addition, since the number of times of replacing the paper dust removing filter 17 increases, it is possible to always maintain a state in which the paper dust removing property can be improved.

As can be seen from the above description, in the image forming apparatus of this embodiment, the paper dust removing means including the paper dust removing filter 17, the pressure release filter 20, and the toner supply container 22 are common. It is attached to the unit plate 25, and these are integrally assembled. That is, the pressure release filter 20, the paper dust removing means, and the toner supply container 22 are integrally and detachably attached to the developing device main body. With this configuration, when the toner supply container 22 is replaced, both filters 1
7, 20 can be exchanged simultaneously. The three parties can be exchanged in one operation, and the number of maintenance operations can be effectively reduced. In particular, since the toner replenishing container 22 is frequently replaced,
By replacing the paper dust removing filter 17 and the pressure release filter 20 each time the toner supply container 22 is replaced,
These filters can always be kept free from clogging by paper dust and the like, so that the passage of the developer and the pressure relief can be prevented from being reduced.

As described above, in the illustrated image forming apparatus, the paper dust removal filter 17, the pressure release filter 20,
The toner supply container 22 and the toner supply container 22 are integrally attached to the unit plate 25, respectively.
5 is detachably fixed to the developing casing 9 by screws 26. If the screws 26 are removed and the unit plate 25 is removed from the developing casing 9, all three members can be replaced at the same time. The paper dust removal filter 1
If the filters 17 and 20 can be used for subsequent use only by cleaning them without replacing the filters 7 and the depressurizing filters 20, etc.
If it is configured to be detachable from the unit 5, the unit plate 25 can be used continuously. In this case, only the toner supply container 22 is replaced.

Except for the depressurizing filter 20, the paper dust removing filter 17, which is an example of the paper dust removing means, and the toner supply container 22 are integrally and detachably attached to the developing device main body. May be provided. In the case of this example, the paper dust removing filter 17 and the toner supply container 22 are provided on the unit plate 25 which is detachably fixed to the developing device main body. On the other hand, the pressure release filter 20 is provided on the developing casing 9 separately from the unit plate 25.

In addition, the pressure release filter 20 and the toner supply container 22 may be provided integrally with the unit plate 25 except for the paper dust removal filter 17, and in this case,
The paper dust removing filter 17 is attached to the developing casing 9 separately from the unit plate 25. With this configuration, when the toner supply container 22 is replaced, the pressure release filter 20 can be replaced at the same time, so that the number of maintenance operations can be reduced, and the filter 20 can always be in a state of good pressure release. In addition, both the paper dust removing filter 17 and the pressure release filter 20 may be integrally provided on the unit plate 25 except for the toner supply container 22.

Further, the paper dust removing filter 17, which is an example of the construction of the paper dust removing means, is configured to be detachable independently of the developing device main body independently of the pressure release filter 20, the toner supply container 22, and the like. By doing so, when the paper dust removing filter 17 is clogged with paper dust, such a clogged state can be eliminated by replacing it alone or cleaning it alone. Thus, the toner collected in the developing device can be reliably and smoothly sent to the developing unit without staying in the paper dust removing filter 17.

As described above, the paper dust removing filter, the pressure release filter 20 and the toner replenishing container 22 can be appropriately combined and integrated, and these can be detachably attached to the developing device main body.

The present invention relates to an image forming apparatus using a roller-shaped cleaning member or an endless belt-shaped member, or an image forming apparatus using an endless belt-shaped one instead of a drum-shaped image carrier. Applicable 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 an image carrier is charged by a charging unit, an electrostatic latent image is formed by a portion not irradiated with light, and a toner charged to a polarity opposite to the polarity of the potential is attached to develop the image. This is also applicable to an image forming apparatus of a so-called positive / positive developing system. Further, the present invention can be applied to an image forming apparatus using a developing device using a one-component toner having no carrier as a developer.

[0061]

According to the image forming apparatus of the present invention, the transfer residual toner collected by the cleaning member is re-attached to the image carrier, and the re-adhered toner is collected by the developing device. Since paper dust mixed in the toner collected in the developing device can be removed, it is possible to prevent image quality deterioration due to the paper dust.

Further, it is possible to prevent an increase in the internal pressure of the developing device, to make it difficult for toner and paper dust to scatter outside the developing device, and to replace the paper dust removing means and the pressure release filter at the same time. Less frequent,
Maintenance frequency can be reduced.

According to the image forming apparatus of the second aspect,
The depressurizing filter provided in the opening for preventing internal pressure rise, the paper dust removing means, and the toner supply container can be exchanged or cleaned together, eliminating the need for separate maintenance and simplifying this kind of maintenance work. Can be

According to the image forming apparatus of the third aspect,
The structure of the paper dust removing means can be simplified, the cost can be reduced, and the paper dust in the developer can be efficiently removed.

[0065]

[0066]

[Brief description of the drawings]

FIG. 1 is a cross-sectional view illustrating a schematic configuration of an image forming apparatus according to an embodiment of the present invention.

FIG. 2 is an explanatory diagram schematically showing an enlarged frictional contact portion between a photosensitive member and a cleaning roller in order to explain a relative positional relationship between the photosensitive member and a cleaning roller.

[Explanation of symbols]

 Reference Signs List 4 developing device 8 transfer unit 16 paper dust 17 paper dust removal filter 19 air release opening 20 pressure release filter 22 toner supply container T 'toner

──────────────────────────────────────────────────続 き Continuation of the front page (72) Inventor Masako Suzuki 1-3-6 Nakamagome, Ota-ku, Tokyo Inside Ricoh Co., Ltd. (56) References JP-A-57-70572 (JP, A) 6-118791 (JP, A) JP-B 61-30274 (JP, B1) (58) Fields investigated (Int. Cl. ⁷ , DB name) G03G 21/10-21/12 G03G 15/00 550 G03G 21 / 16-21/18 G03G 21/00 530-540 G03G 15/08-15/08 507

Claims (3)

(57) [Claims] 1. An image bearing member which is driven to rotate is uniformly charged by a charging means, and the charged surface is exposed and scanned to form an electrostatic latent image on the image bearing member. Is visualized as a toner image by a developing device, the toner image is transferred to a recording medium by a transfer unit, and after the transfer of the toner image, the toner remaining on the image carrier is temporarily collected by a cleaning member. Next, the collected toner is re-attached to a surface portion of the image carrier that does not affect the formation of the next latent image, and the re-adhered toner is collected by a developing device. A paper dust removing means for removing paper dust mixed in the collected toner is provided in the developing device, and the developing device has an air release opening for preventing the internal pressure of the device main body from rising, and is provided in the opening. Out of the developing device body A depressurizing filter that allows air to flow out and prevents the passage of the developer outside the developing device main body; and the depressurizing filter and the paper dust removing unit are integrated with the developing device main body, and An image forming apparatus which is detachably mounted. 2. The image forming apparatus according to claim 1, wherein the pressure release filter, the paper dust removing unit, and the toner supply container are integrally and detachably mounted on the developing device main body. 3. The image forming apparatus according to claim 1, wherein the paper dust removing means comprises a paper dust removing filter, and the filter is provided in a developer circulation path in the developing device main body.