JP2006259579A - Image forming apparatus and cleaning device used for the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image forming apparatus with a stable cleaning performance without being constrained on the layout of the peripheral devices of an image carrier and the positional relation of an image conveyor and the image carrier, and a cleaning device used for it. <P>SOLUTION: The image forming apparatus of transferring a toner image on the image carrier 1 to a recording material by using the image conveyor 2 comprises: an image carrier cleaning device 3 for collecting waste toner remaining on the image carrier 1; and an image conveyor cleaning device 4 for collecting the waste toner remaining on the image conveyor 2. The image carrier cleaning device 3 is provided with: a collection housing 5 for temporarily housing the waste toner; a cleaning member 6 for removing the waste toner on the image carrier 1; and a waste toner transfer body 7 provided inside the collection housing 5 and brought into contact with the image conveyor 2 at timing of not damaging imaging toner on the image conveyor 2 to transfer the waste toner inside the collection housing 5 to the image conveyor 2. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an image forming apparatus such as a copying machine, a printer, and a facsimile, and more particularly to an improvement of an image forming apparatus including a cleaning device using an image transfer body such as an intermediate transfer body or a recording material transfer body.

  Conventionally, as an example of an image forming apparatus employing an intermediate transfer system as an image forming apparatus such as a printer or a copying machine using an electrophotographic system, for example, charging, exposure, development, transfer and cleaning around a photosensitive drum. Each of the electrophotographic devices is disposed, while an intermediate transfer belt is disposed opposite to the transfer bias disposed portion of the photosensitive drum, and a toner image is formed on the photosensitive drum, and then the intermediate transfer belt and the intermediate transfer are formed. The toner image is primarily transferred to the intermediate transfer belt by electrostatic action at the primary transfer position with the belt, and then the toner image on the intermediate transfer belt is secondarily transferred to the recording material at the secondary transfer position. In some cases, an image is formed on a recording material by electrostatic action.

Here, at the time of primary transfer, the toner image on the photosensitive drum is not entirely transferred onto the intermediate transfer belt, and a part of the toner image remains on the photosensitive drum. In order to collect the residual toner, it is necessary to provide a photoconductor cleaning device that cleans the surface of the photoconductor drum downstream of the primary transfer position in the rotation direction of the photoconductor drum.
Also, in the secondary transfer, when the toner image is transferred from the intermediate transfer belt to the recording material, not all of the toner on the intermediate transfer belt is transferred to the recording material. To remain. For this reason, an intermediate cleaning device for removing toner remaining on the intermediate transfer belt is provided downstream of the secondary transfer position in the direction of travel of the intermediate transfer belt.

In this type of aspect, it is necessary to provide independent cleaning devices in the vicinity of the photosensitive drum and in the vicinity of the intermediate transfer belt, so it is necessary to secure an installation space corresponding to the cleaning housing for collecting waste toner. Accordingly, the process cartridge and the image forming apparatus are increased in size, and the request for downsizing the apparatus cannot be met.
Therefore, after scraping off the waste toner on the photosensitive drum with a cleaning member (rotating brush or the like), the waste toner adhering to the cleaning member is wiped off onto the intermediate transfer belt by a flicker bar, and the intermediate transfer belt is discarded. A method has been proposed in which waste toner is centrally collected by an intermediate cleaning device by conveying toner (see Patent Document 1).
This type of prior art pays attention to the fact that the charging polarity of the waste toner discharged from the photosensitive member cleaning device to the intermediate transfer belt is opposite to that in the toner image being formed. Even when the toner image transferred onto the paper is secondarily transferred onto the paper, the waste toner moves on the intermediate transfer belt without being transferred onto the paper and is collected by the intermediate cleaning device. The formed image does not cause image quality defects due to waste toner.

Japanese Patent Laying-Open No. 2003-186364 (see Embodiment of the Invention, FIG. 1)

However, in the prior art described in Patent Document 1, in order to transfer the waste toner by using the rotational force of the rotating brush or the drop due to gravity, an intermediate transfer belt must be provided below the photosensitive drum. From the viewpoint of preventing waste toner scattering, it is necessary to arrange the photoconductor cleaning device and the intermediate transfer belt close to each other. A great deal of restrictions are imposed on the positional relationship between the photosensitive drum and the photosensitive drum.
Further, the residual toner on the photosensitive drum is always discharged onto the intermediate transfer belt by the photosensitive member cleaning device, but the waste toner released onto the intermediate transfer belt is temporarily replaced with the toner in the toner image being formed. When toners of the same polarity are mixed, it is inevitable that the waste toner is transferred to the paper side during the secondary transfer.
Further, in this type of prior art, there is an aspect in which the amount and timing of waste toner discharge is controlled by providing a shutter. In this aspect, although waste toner discharge during image formation can be avoided, the waste toner is discarded. There arises a problem that the toner cannot be stably discharged.
Such a technical problem similarly occurs in an embodiment using a recording material conveyance body.

  The present invention has been made in order to solve the above technical problem, and while satisfying the demand for downsizing of the apparatus, the layout of peripheral devices of an image carrier such as a photosensitive drum and the image of an intermediate transfer member and the like. It is an object of the present invention to provide an image forming apparatus having a stable cleaning performance and a cleaning device used therefor, without being restricted in the positional relationship between the conveyance body and the image carrier.

That is, according to the present invention, as shown in FIG. 1, in an image forming apparatus in which a toner image formed on an image carrier 1 is transferred to a recording material using an image carrier 2, the image is formed on the image carrier 1. An image carrier cleaning device 3 that collects residual waste toner and an image carrier cleaning device 4 that collects waste toner remaining on the image carrier 2 are provided. The image carrier cleaning device 3 includes the image carrier 1 and the image carrier. A recovery housing 5 disposed opposite to the body 2 and temporarily recovering waste toner, and a cleaning housing 5 provided in the recovery housing 5 and removing residual toner remaining on the image carrier 1 and storing it in the recovery housing 5 Waste toner that is provided in the member 6 and the collection housing 5 and contacts the image carrier 2 at a timing at which the toner image formed on the image carrier 2 is not damaged and is accommodated in the collection housing 5 is removed. Characterized by comprising a waste toner transfer member 7 to be transferred to the carrier 2.
Here, the image carrier 2 includes not only an intermediate transfer member but also a recording material carrier. Hereinafter, the present invention will be described by taking an example in which the image carrier 2 is an intermediate transfer member. The present invention describes a toner image formed on the image carrier 1 as an intermediate transfer member 2 (image carrier 2). In the image forming apparatus in which the toner is transferred to a recording material using an image carrier, an image carrier cleaning device 3 that collects waste toner remaining on the image carrier 1 and an image transport that collects waste toner remaining on the intermediate transfer body 2 are collected. A cleaning device 4. The image carrier cleaning device 3 is disposed opposite to the image carrier 1 and the intermediate transfer member 2 and temporarily collects waste toner. The image housing cleaning device 3 is provided in the collection housing 5. A cleaning member 6 that removes waste toner remaining on the image carrier 1 and accommodates it in the recovery housing 5 and a toner image that is provided in the recovery housing 5 and formed on the intermediate transfer body 2 is not damaged. It is characterized in that an intermediate transfer body 2 waste toner transfer member 7 to transfer the waste toner contained in the intermediate transfer body 2 in contact with and collecting housing 5.

In such technical means, the application range of the image forming method of the present invention may be appropriately selected as long as the toner image is visualized, and widely includes an electrophotographic method and an electrostatic recording method. In the case of the intermediate transfer system, a multi-cycle type in which one image carrier 1 is rotated a plurality of times, or a tandem type in which a plurality of image carriers 1 are arranged side by side may be appropriately selected.
Further, the image carrier 1 may be selected as appropriate, such as a photoreceptor or a dielectric, and may be in the form of a belt, a drum, or the like.
Furthermore, the intermediate transfer member 2 may be either elastic or rigid, and may be appropriately selected such as a belt shape or a drum shape.
Further, regarding the positional relationship between the intermediate transfer member 2 and the image carrier 1, the image carrier 2 may be disposed above, below, or on the side of the image carrier 1.

Further, the cleaning method of the image carrier cleaning device 3 may be an aspect in which it is electrostatically attached and recovered in addition to a mechanical scraping aspect, and may be appropriately selected. The cleaning member 6 disposed in the image carrier cleaning device 3 may be appropriately selected from a blade, a brush, a roll, and the like.
Furthermore, the recovery housing 5 may be provided so as to face the image carrier 1 and the intermediate transfer body 2, and usually has an opening for taking in and out the waste toner at each facing portion. In this case, the opening 5a on the image carrier 1 side should normally be in a mode of being always open, but the opening 5b on the side of the intermediate transfer body 2 may be in a mode of being always open, or, for example, a shutter And may be opened and closed at a predetermined timing. And in the aspect which provided the shutter, the contamination of the image carrier 1 by the cloud in a housing can be prevented.
The volume of the collection housing 5 may be set as appropriate as long as the waste toner can be temporarily collected, and can be smaller than the waste toner collection and storage type.

Furthermore, the waste toner transfer body 7 is only required to realize the function of the waste toner transfer body 7 (function of transferring the waste toner temporarily collected to the intermediate transfer body 2 side). It is possible to select the attachment method as appropriate. Further, the waste toner transfer body 7 may be provided singly or plurally, and the shape thereof may be appropriately selected such as a roll shape or a brush shape.
Further, the cleaning method of the image transport cleaning device 4 may be a mode in which it is electrostatically attached and recovered in addition to a mechanical scraping mode. The cleaning member 9 disposed in the housing 8 may be a roll, a blade, a brush, or the like. Furthermore, since the housing 8 not only collects the residual toner on the intermediate transfer body 2 but also collects the waste toner in the collection housing 5, the housing 8 needs to have a volume that can be accommodated.

Further, as a preferable aspect of the waste toner transfer body 7, for example, the waste toner transfer body 7 is supported movably by a retracting means, and can be moved between a contact position that contacts the intermediate transfer body 2 and a separation position that is separated from the intermediate transfer body 2. The one that was made. In this case, it is preferable that the retracting means swing and support the waste toner transfer body 7 so that the waste toner transfer body 7 can be brought into contact with and separated from the intermediate transfer body 2 with a simple configuration.
Further, the retracting means may be appropriately selected such as a simple driving source such as a solenoid.
Further, the retracting means operates based on the information of the image writing timing of the exposure apparatus, and is a waste toner transfer body at a position where the toner image (image forming area) formed on the intermediate transfer body 2 is not damaged. 7 is preferably contacted.

Further, the waste toner transfer body 7 has a mode in which the waste toner in the collection housing 5 is transferred upward or a side transfer according to the mode of the arrangement position of the intermediate transfer body 2 with respect to the image carrier 1. The mode of transferring downward may be appropriately selected.
The waste toner transfer body 7 is preferably rotatable when in contact with the intermediate transfer body 2. In this case, examples of the rotation method of the intermediate transfer body 2 include a rotatable natural rotation method and a forced rotation method equipped with a driving mechanism.
As described above, by using a rotatable member for the waste toner transfer body 7, it is possible to reduce the rotational load fluctuation when contacting the intermediate transfer body 2.
In this embodiment, the waste toner transfer body 7 may be appropriately selected such as a rotating brush or a rotating roll.

Further, it is preferable that the waste toner transfer body 7 adopts a forced rotation system and has a rotation speed substantially equal to the rotation speed of the intermediate transfer body 2 when in contact with the intermediate transfer body 2.
As such a forced rotation system, a mode in which a drive mechanism capable of applying a rotational drive force to the waste toner transfer body 7 is provided.
According to this aspect, since the rotational load on the intermediate transfer body 2 can be eliminated, color registration misalignment can be suppressed.

Further, it is preferable that the waste toner transfer body 7 is provided with a transition electric field forming means so that the waste toner transfer electric field generated by the transfer electric field forming means acts between the intermediate transfer body 2 and the intermediate transfer body 2.
In this way, by causing the waste toner transfer electric field to act, the transferability and adhesion of the waste toner to the intermediate transfer body 2 can be improved.
Further, in this case, when a bias is applied to the waste toner transport body 7, it is preferable to provide a counter electrode corresponding to the waste toner transfer body 7 with the intermediate transfer body 2 interposed therebetween.

Further, the bias applied to the waste toner transfer body 7 may be appropriately selected. Specifically, the polarity of the waste toner in the collection housing 5 may be made uniform, for example, as long as it can be transferred to the intermediate transfer body 2 side, and a DC bias, an AC bias, or a combination of both Etc. can be appropriately selected.
Further, when transferring the waste toner to the intermediate transfer body 2 or before it, the polarity of the waste toner may be made uniform. For example, when the waste toner has a negative polarity, the waste toner and the waste toner transfer body 7 A mode in which a process of rearranging the polarity of the waste toner to a predetermined polarity (for example, negative polarity) by rubbing the toner may be appropriately selected.

  Furthermore, the waste toner transfer body 7 is preferably in contact with a non-image forming area (inter-image portion) located between the image forming areas on the intermediate transfer body 2. According to this aspect, waste toner can be attached to the inter-image portion on the intermediate transfer body 2 and conveyed, so that the toner image and waste toner in the image forming area on the intermediate transfer body 2 are mixed. Never do.

  The waste toner transfer body 7 is preferably in contact with the intermediate transfer body 2 by providing a cleaning cycle different from the image forming cycle. Here, the timing for selecting the cleaning cycle may be selected as appropriate for each image forming cycle, but the amount of waste toner is not so large, so it is performed every image forming cycle for a certain number (50 sheets, 100 sheets, etc.). It is preferable.

  The present invention is also directed to a cleaning device used as the image carrier cleaning device 3 in the above-described image forming apparatus.

According to the image forming apparatus of the present invention, the waste toner transfer body is provided in the recovery housing of the image carrier cleaning device in addition to the cleaning member, and the waste toner temporarily recovered in the recovery housing by the waste toner transfer body is disposed on the image carrier side. The image carrier cleaning device is almost free of restrictions on the layout of peripheral devices of the image carrier such as the photosensitive drum and the positional relationship between the image carrier and the image carrier such as the intermediate transfer member. The waste toner on the image carrier can be processed on the side of the image conveyance cleaning device through the image conveyance body while reducing the installation space.
Further, according to the present invention, the waste toner in the collection housing of the image carrier cleaning device is forcibly transferred onto the image carrier at a timing that does not impair the toner image on the image carrier, so that it is mixed with the toner image. It is possible to effectively avoid such a situation.
Further, according to the present invention, the waste toner storage locations are concentrated in the storage housing of the image transport cleaning device, and the image carrier cleaning device has a recovery housing that can temporarily store the waste toner on the image carrier. Therefore, it is possible to centralize waste toner storage locations, to reduce the size of the image carrier cleaning device, and to increase the degree of freedom in layout of peripheral devices of the image carrier. In addition, the cartridge configuration including the image carrier can be reduced in size.
Further, according to the cleaning device used as the image carrier cleaning device in such an image forming apparatus, a small image forming apparatus having a good cleaning performance can be easily constructed.

Hereinafter, the present invention will be described in detail based on embodiments shown in the accompanying drawings.
Embodiment 1
FIG. 2 shows Embodiment 1 of an image forming apparatus to which the present invention is applied.
In FIG. 1, the image forming apparatus includes a photosensitive drum 10 and an intermediate transfer belt 20 that is disposed to face the photosensitive drum 10 and that transfers a toner image from the photosensitive drum 10.
In the present embodiment, the photosensitive drum 10 includes a photosensitive layer whose resistance value is reduced by light irradiation. Around the photosensitive drum 10, a charging device 11 for charging the photosensitive drum 10 and An exposure device 12 for writing an electrostatic latent image of each color component (in this example, yellow (Y), magenta (M), cyan (C), black (K)) on the charged photosensitive drum 10, and a photosensitive member. A rotary developing device 13 that visualizes each color component latent image formed on the drum 10 with each color component toner, and a photoconductor cleaner (image carrier) that cleans residual toner (waste toner) on the photoconductor drum 10. 17 corresponding to a cleaning device).

Here, as the charging device 11, for example, a charging roll is used, but a charging device such as a corotron may be used.
The exposure device 12 may be any device that can write an image on the photosensitive drum 10 with light. In this example, for example, a print head using LEDs is used, but the present invention is not limited to this, and EL is used. For example, a scanner that scans a laser beam with a polygon mirror may be selected as appropriate.
Further, the rotary type developing device 13 is rotatably mounted with developing devices 13a to 13d containing respective color component toners. For example, the respective color component toners are attached to a portion of the photosensitive drum 10 where the potential is lowered by exposure. The toner to be used is not particularly limited in shape and particle size, and any toner may be used as long as it is accurately placed on the electrostatic latent image on the photosensitive drum 10.

In the present embodiment, the rotary developing device 13 includes the developing devices 13a to 13d mounted on a rotating holder 132 that can rotate around a rotating shaft 131. By rotating the rotating holder 132, the rotary developing device 13 is rotated. Each of the developing devices 13a to 13d is selectively disposed at a developing position facing the photosensitive drum 10.
Here, each of the developing units 13a to 13d has a developing housing 133 that is open at a portion facing the photosensitive drum 10 in a state where the developing units 13a to 13d are arranged at the developing position, for example, at a portion facing the opening of the developing housing 133. A developing roll 134 is disposed, and a pair of transport agitating augers 135 and 136 are disposed on the back side of the developing roll 134. Reference numeral 137 denotes a toner supply / conveyance member for supplying a predetermined amount of toner in the toner cartridge 138 attached to the outside of the developing housing 133.
The details of the photoconductor cleaner 17 will be described later.

Further, in the present embodiment, the intermediate transfer belt 20 is stretched around a plurality of stretching rolls 21 to 23 and is rotated in a predetermined direction using, for example, the stretching roll 23 as a driving roll. As the intermediate transfer belt 20 used here, for example, a predetermined thickness is prepared by dispersing a predetermined amount of a resistance adjusting agent such as carbon in a resin such as polyimide resin or polyamide resin.
A primary transfer roll 25 as a primary transfer device is disposed in contact with a part of the contact area where the intermediate transfer belt 20 is in close contact with the photosensitive drum 10 from the back side of the intermediate transfer belt 20, and a predetermined primary transfer bias is applied. Applied.
Furthermore, a secondary transfer roll 30 as a secondary transfer device is disposed opposite to the tension roll 22 of the intermediate transfer belt 20 with the tension roll 22 as a backup roll, for example, the secondary transfer roll 30. A predetermined secondary transfer bias is applied to the tension roller 22 and the tension roll 22 that also serves as a backup roll is grounded.
Furthermore, a belt cleaner (corresponding to an image transport cleaning device) 26 is disposed at a portion of the intermediate transfer belt 20 facing the stretching roll 21. Further, the belt cleaner 26 includes a cleaning blade 28 that scrapes off the residual toner on the intermediate transfer belt 20, and a storage housing 27 that collects the scraped residual toner.

  A recording material 40 such as paper is accommodated in a supply tray 41, supplied by a pickup roll 42, guided to a secondary transfer site via a registration roll 43, and then conveyed to a fixing device 45. Then, it is discharged to a discharge tray 48 through a discharge roll 47.

In particular, the present embodiment has a characteristic point in the configuration of the photoconductor cleaner (corresponding to an image carrying cleaning device) 17.
In the present embodiment, as shown in FIG. 3A, the photoconductor cleaner 17 has a recovery housing 170 that opens to face the photoconductor drum 10 and the intermediate transfer belt 20. A cleaning blade 171 is provided at one side edge of the opening on the body drum 10 side, and the tip of the cleaning blade 171 is disposed in contact with the photosensitive drum 10.
Further, a waste toner transfer body 173 is movably provided in the collection housing 170. In the present embodiment, the waste toner transfer body 173 is configured by a rotatable rotating brush 174, and a contact position where the retract mechanism 175 contacts the intermediate transfer belt 20 and a retracted position separated from the intermediate transfer belt 20. It is supported so that it can move between.
In the figure, reference numeral 172 denotes a film seal for preventing scattering of waste toner scraped by the cleaning blade 171.

  Furthermore, in the present embodiment, the recovery housing 170 only needs to be able to temporarily store the waste toner recovered from the photosensitive drum 10 and to secure a space in which the waste toner transfer body 173 can swing. A type smaller than the recovery housing 170 of the photosensitive drum cleaner 17 can be used.

In this embodiment, the waste toner transfer body 173 is supported by the retract mechanism 175 so as to be swingable.
The retract mechanism 175 has a substantially V-shaped link arm 176, which allows the bent portion of the linkome 176 to swing as a rotation fulcrum 178, and the tip of one arm portion of the link arm 176 and the shift actuator 177. The rotating brush 174, which is a waste toner transfer body 173, is rotatably supported near the tip of the other arm portion of the link arm 176. Further, a control device (not shown) is connected to the retract mechanism 175, and this control device operates (extends / contracts) the shift actuator 177 according to image writing timing information of the exposure device 12, for example, according to the flowchart shown in FIG. Switching is to be performed.

Further, as shown in FIG. 4A, a bias power source 180 is connected to the central axis of the rotating brush 174. The bias power supply 180 is connected so that a positive DC bias V (+) is applied.
Further, reference numeral 181 in the figure denotes a counter electrode to which a waste toner transfer electric field can act by a bias V (+) from the waste toner transfer body 173. The counter electrode 181 is formed, for example, as a conductive roll, and is disposed in contact with the back surface of the intermediate transfer belt 20 at a portion facing the waste toner transfer body 173 and grounded.

Next, an image forming process of the color image forming apparatus according to the present embodiment will be described. First, the surface of the photosensitive drum 10 is uniformly charged to, for example, negative polarity by the charging device 11. Next, image exposure corresponding to the first color, for example, a yellow image, is performed by the laser scanning device (exposure device) 12, and an electrostatic latent image corresponding to the yellow image is formed on the surface of the photosensitive drum 10. Further, the yellow developing device 13 a faces the photosensitive drum 10 and forms yellow toner on the photosensitive drum 10. Then, after development is performed by the corresponding developing device, the image is transferred onto the intermediate transfer belt 20 by the primary transfer roll 25.
By the way, with respect to the photosensitive drum 10 after the transfer of the yellow toner image, the yellow toner remaining on the surface of the photosensitive drum 10 is scraped off by the photosensitive member cleaner 17 and accommodated in the recovery housing 170.
Next, for the second color, for example, a magenta image forming process, the surface of the photosensitive drum 10 is uniformly charged to a negative polarity by the charging device 11, and image exposure corresponding to the magenta image is performed by the laser scanning device 12. An electrostatic latent image of a magenta image is formed on the surface of the photosensitive drum 10. The rotary developing device 13 is switched so that the magenta developing device 13b faces the photosensitive drum 10 after finishing the formation of the yellow toner image, and the electrostatic latent image corresponding to the magenta image is Developed. Then, the magenta toner image is multiple-transferred onto the yellow toner image on the intermediate transfer belt 20. After the transfer of the magenta toner image, the photosensitive drum 10 is then cleaned of residual toner on the surface of the photoconductor cleaner 17 in the same manner as the yellow image forming process, while the transfer of the magenta toner image is completed. The intermediate transfer belt 20 is prepared for the next step.

  Further, like the magenta image forming process, a third color, for example, a cyan image forming process is performed, and finally, a fourth color, for example, a black image forming process is performed. Then, a cyan image and a black image are transferred onto the yellow toner image and the magenta toner image on the intermediate transfer belt 20 in multiple colors. After the transfer of the black toner image of the final color, the surface of the photoreceptor drum 10 is cleaned by the photoreceptor cleaner 17 in the same manner as in each color image forming process.

  On the other hand, the recording material 40 is transported from the supply tray 41, temporarily clogged by the registration roll 43, and then sent to the nip area between the secondary transfer roll 30 and the backup roll 22 at a predetermined timing. The four-color toner image thus transferred and transferred is collectively transferred onto the recording material 40 in the nip area between the secondary transfer roll 30 and the backup roll 22, and then conveyed to the fixing device 45, where the conveyance roll 46 and the discharge roll. 47 is discharged to the discharge tray 48.

In such an image forming process, in the photoreceptor cleaner 17, the waste toner transfer body 173 can transfer the waste toner in the collection housing 170 to the intermediate transfer belt 20 as appropriate.
That is, when the superposition of the four colors is finished, as shown in FIG. 5, the control device receives information on the write timing of the exposure device 12, measures the image forming cycle by the counter counting operation, and reaches the set number of sheets. If there is, the waste toner transfer body 173 switches to a transfer mode in which the waste toner in the collection housing 170 is transferred to the intermediate transfer belt 20.

The operation of the waste toner transfer body 173 in this transfer mode will be described in detail.
Now, waste toner (mainly positive polarity) scraped by the cleaning blade 171 accumulates on the rotating brush 174 located in the bottom wall portion of the collecting housing 170 or in the vicinity of the rotating brush 174 in the collecting housing 170. As a result, waste toner adheres to the surface of the rotating brush 174.
When the mode is switched to the transfer mode, the shift actuator 177 operates and the cylinder 177a contracts as shown in FIG. Along with this, the link arm 176 rotates about the rotation fulcrum 178 in the clockwise direction in the figure. As a result, the rotary brush 174 disposed in the vicinity of the end of the arm portion of the link arm 176 moves to the intermediate transfer belt 20 side with waste toner attached thereto.
Further, the present invention is not limited to such a mechanical transfer mode, and when the rotating brush 174 contacts the intermediate transfer belt 20, a positive polarity bias larger than the bias of the intermediate transfer belt 20 is applied to the bias power source 180. When the electrostatic method is adopted, it is possible to electrostatically transfer the positive waste toner adhering to the waste toner transfer body 173 onto the intermediate transfer belt 20 (see FIG. 4B). .
In such a transfer mode, the place where the waste toner transfer body 173 contacts the intermediate transfer belt 20 is the inter image 61 (see FIG. 6) outside the image forming area 60, and the waste toner protrudes into the image forming area 60. There is no such thing.

The waste toner conveyed by the intermediate transfer belt 20 in this manner is not transferred to the recording material 40 in the secondary transfer, and the residual toner of the toner image remaining on the intermediate transfer belt 20, and the cleaning blade 28 of the belt cleaner 26. Is scraped off and collected in the housing 27.
In this embodiment, if the inter image 61 is short and the waste toner transportability is low, a new cleaning cycle is provided at a timing different from the image forming cycle, and the waste toner is continuously discharged when the image writing is not performed. By adopting the transfer method, it becomes possible to transfer more waste toner to the intermediate transfer belt 20.

◎ Deformation 1
FIG. 7A shows a first modification of the bias power supply 180 used in the first embodiment.
In the figure, since the basic configuration other than the photoconductor cleaner 17 is substantially the same as that of the first embodiment, the description thereof is omitted here. The same applies to the following description.
Unlike the first embodiment, this variation is configured to apply a negative transfer electric field when waste toner collected in the collection housing 170 contains many negative ones.
That is, this modification is directed to an aspect in which the charging polarity of the surface of the photosensitive drum 10 charged by the charging device 11 is positively charged. In such an aspect, the recovery is performed in the recovery housing 170. Many of the waste toners are negatively charged.
In order to apply a waste toner transfer electric field that transfers waste toner in the collection housing 170 to the intermediate transfer belt 20, a negative bias power source 183 is connected to the central axis of the waste toner transfer body 173.

Next, an operation when the waste toner transfer body 173 transfers the waste toner to the intermediate transfer belt 20 will be described (see FIG. 7B).
When the waste toner transfer body 173 is switched to a transfer mode in which waste toner in the collection housing 170 is transferred to the intermediate transfer belt 20, the waste toner transfer body 173 having the waste toner attached to the surface at the bottom wall portion of the collection housing 170 is retracted. The mechanism 175 moves to the vicinity of the intermediate transfer belt 20.
When the waste toner transfer body 173 comes into contact with the intermediate transfer belt 20, the bias power source 183 applies a DC bias V (−) having a larger absolute value than the negative potential of the intermediate transfer belt 20 to be discarded. When a waste toner transfer electric field acts between the toner transfer body 173 and the intermediate transfer belt 20, the negative waste toner adhering to the surface of the waste toner transfer body 173 is electrostatically transferred onto the intermediate transfer belt 20. Is.

◎ Deformation 2
FIG. 8 shows a second modification of the bias power supply 180 used in the first embodiment.
In this modification, when the waste toner in the collection housing 170 is, for example, a mixture of positive and negative toners, an alternating electric field is applied to the waste toner transfer electric field by switching positive and negative biases as needed. It is a thing.
That is, when the waste toner transfer body 173 is brought into contact with the intermediate transfer belt 20, the positive and negative bias power supplies 184 (AC bias) are alternately applied.
Even in such an aspect, good transferability can be obtained as in the first embodiment.

Embodiment 2
FIGS. 9A and 9B show the photoconductor cleaner 17 according to the second exemplary embodiment.
In the present embodiment, a fixed brush 202 is used for the waste toner transfer body 173. Such a fixed brush 202 can be conveyed onto the intermediate transfer belt 20 by electrostatically adhering waste toner in the collection housing 170.
In this embodiment, as shown in FIG. 9B, the tension roll 24 disposed in contact with the back surface of the intermediate transfer belt 20 also serves as the counter electrode 181 of the waste toner transfer body 173. In this aspect, since the distance m between the fixed brush 202 and the tension roll 24 is set to be sufficiently small, a waste toner transfer electric field can act between the fixed brush 202 and the tension roll 24 that is grounded. Is possible.
Even in such an embodiment using the fixed brush 202, the waste toner in the collection housing 170 is electrostatically attached to the fixed brush 202, and a waste toner transfer electric field equivalent to that in the first embodiment is applied. Since it is possible, it can be transferred onto the intermediate transfer belt 20.

Embodiment 3
10 and 11 (a) and 11 (b) show a photoreceptor cleaner 17 according to the third embodiment. As shown in the figure, the waste toner transfer body 173 is configured by a rotating brush as in the first embodiment. However, unlike the first embodiment, the waste toner transfer body 173 is forcibly rotated by a drive mechanism 219. It has become.
The drive mechanism 219 in this embodiment includes a motor 220 as a drive source, and includes a drive gear 221 that is coupled to the motor 220 and a driven gear 222 that is meshed with the drive gear 221. Further, the rotation shaft 223 of the driven gear 222 also serves as the rotation fulcrum 178 of the link arm 176 and is provided with a drive transmission pulley 224. Further, the drive transmission pulley 224 is connected to the driven pulley 226 via the drive transmission belt 225 so as to be able to transmit the drive, and the rotary shaft 227 of the driven pulley 226 is provided with a rotary drive brush 211 on the other side.

Next, the operation of the photoconductor cleaner 17 according to the present embodiment will be described.
As in the first embodiment, when each color image forming process is completed on the intermediate transfer belt 20, the control device receives information on the write timing of the exposure device 12, and performs a counter counting operation. As a result, if the set number of sheets is reached, the waste toner transfer body 173 switches to a transfer mode in which the waste toner in the collection housing 170 is transferred to the intermediate transfer belt 20 (see FIG. 5).
When the mode is switched to the transfer mode, the drive mechanism 219 is activated. That is, when the motor 220 is operated and the drive gear 221 is driven to rotate, the drive rotation of the drive gear 221 is transmitted to the driven gear 222 and the rotating shaft 223 rotates. Further, the rotational force transmitted to the drive transmission pulley 224 by the rotation of the rotary shaft 223 is transmitted to the rotary shaft 227 of the rotary drive brush 211 via the drive transmission belt 225 and the driven pulley 226.
By such a drive mechanism 219, the rotational drive brush 211 can rotate at the same speed as the intermediate transfer belt 20 on the bottom wall portion of the collection housing 170, and waste toner accumulated in the collection housing 170 by the rotation can be removed. It can be mechanically attached to the surface of the rotary drive brush 211.

Further, the rotation driving brush 211 is moved to the intermediate transfer belt 20 side by the retract mechanism 175.
That is, when the cylinder 177a of the shift actuator 177 contracts, the link arm 176 rotates clockwise around the rotation fulcrum 178 (see FIG. 11 (a)), and near the tip of the arm portion of the link arm 176. The arranged rotational drive brush 211 moves to the intermediate transfer belt 20 side. At this time, the rotation drive brush 211 is rotated at substantially the same speed as the intermediate transfer belt 20 by the drive mechanism 219 as described above.
Further, when the rotation driving brush 211 comes into contact with the intermediate transfer belt 20, when a bias is applied and a waste toner transfer electric field acts between the rotation electrode brush 181, the waste toner attached to the rotation driving brush 211 is removed. It is transferred onto the intermediate transfer belt 20 by electrostatic force.
According to the rotation driving brush 211 according to this modification, waste toner can be transferred without applying a load to the rotation of the intermediate transfer belt 20 when in contact with the intermediate transfer belt 20, and color registration misalignment can be generated. It can be effectively avoided.

In particular, in the cleaning device provided with such a drive mechanism 219, when most of the waste toner in the collection housing 170 is negative, a process is provided in which the rotary drive brush 211 rubs and charges the waste toner, and the toner polarity Can be effectively transferred by rearranging to a uniform negative charge.
That is, when the charging polarity of the surface of the photosensitive drum 10 charged by the charging device 11 is positive, many waste toners collected in the recovery housing 170 are negative.
In such an embodiment, a negative electric field is applied as a waste toner transfer electric field for transferring the waste toner in the collection housing 170 to the intermediate transfer belt 20, and the negative axis is applied to the central axis of the rotary drive brush 211. Connect the bias power supply.
Further, in the operation of the present embodiment, when the rotational drive brush 211 slides and rotates on the bottom wall portion of the collection housing 170 in the collection housing 170, the waste toner in the collection housing 170 is rubbed and charged, and the uniform negative electrode And reliably adhere to the surface of the rotary drive brush 211.
The negative waste toner adhering to the surface of the rotary drive brush 211 is a direct current having a bias larger than the negative charge of the intermediate transfer belt 20 when the rotary drive brush 211 contacts the intermediate transfer belt 20. When a waste toner transfer electric field acts between the rotary drive brush 211 and the intermediate transfer belt 20 by applying the bias V (−), the bias is transferred onto the intermediate transfer belt 20 by electrostatic force.
In this way, it is possible to transfer the waste toner more effectively by rearranging the charging polarity of the waste toner to a uniform negative polarity.

Embodiment 4
FIG. 12 shows an image forming apparatus according to Embodiment 4 of the present invention.
In the figure, the image forming apparatus according to the present embodiment is a so-called tandem type, and an image reading unit (not shown) for reading a document is disposed below the apparatus main body 70, while the apparatus main body. An image forming engine 71 (specifically 71a to 71d) of four color components (in this embodiment, Y: yellow, M: magenta, C: cyan, K: black) is arranged in the horizontal direction in 70, Above this, an intermediate transfer belt 90 that is circulated and conveyed along the direction in which the image forming engines 71 are arranged is disposed oppositely.

In the present embodiment, the image forming engine 71 includes, for example, a photosensitive drum 72, a charging device 73 that charges the photosensitive drum 72, and a charged photosensitive drum 72 around the photosensitive drum 72. A latent image writing device (not shown) such as a laser device that writes an electrostatic latent image, a developing device 74 that visualizes the electrostatic latent image on the photosensitive drum 72 with each color component toner, and the photosensitive drum 72 The photoreceptor cleaner 76 (specifically, 76a to 76d) for removing the residual toner is sequentially disposed.
A primary transfer roll 75 as a primary transfer device is disposed in contact with a part of the contact area where the intermediate transfer belt 90 is in close contact with the photosensitive drum 72 from the back side of the intermediate transfer belt 90. Has a function of a counter electrode capable of applying a waste toner transfer electric field.
Further, the retract mechanism connected to the waste toner transfer body 81 is the same as that of the first embodiment.
Furthermore, each developing device 74 has a developing housing 77 opened at a portion facing the photosensitive drum 72 in a state where the developing device 74 is disposed at the developing position, for example, and a developing roll is provided at a position facing the opening of the developing housing 77. 78 and a pair of conveyance agitation augers 79 and 80 are provided on the back side of the developing roll 78. Reference numeral 82 denotes a transport paddle that transports the toner in the developing housing 78 to the developing roll 78 side.
On the other hand, the intermediate transfer belt 90 is stretched around stretch rolls 91 and 92. The stretch roll 91 functions as a drive roll, and the stretch roll of 92 functions as a driven roll.
In addition, a secondary transfer roll 93 as a secondary transfer device is disposed opposite to the tension roll 92 of the intermediate transfer belt 90 with the tension roll 92 as a back roll.
Furthermore, a belt cleaner 94 for cleaning residual toner on the intermediate transfer belt 90 and waste toner in the inter-image portion is disposed at a portion of the intermediate transfer belt 90 that faces the stretch roll 91.
In the figure, reference numeral 95 denotes a recording material.

Next, the operation of the image forming apparatus according to the present embodiment will be described.
In such an image forming engine, the surface of the photosensitive drum 72 is uniformly charged to, for example, negative polarity by the charging device 73. Next, image exposure is performed by an exposure device (not shown), and an electrostatic latent image corresponding to each color is formed on the surface of the photosensitive drum 72. Then, the electrostatic latent image on the photosensitive drum 72 is developed by each developing device 74 to be visualized (toner image).
Further, a bias having a polarity opposite to that of the toner image on the photosensitive drum 72 is applied to the primary transfer roll 75 at the position where the photosensitive drum 72 and the intermediate transfer belt 90 are in contact with each other. The formed toner image is primary-transferred sequentially on the intermediate transfer belt 90 for each color. Further, the toner image primarily transferred onto the intermediate transfer belt 90 is conveyed to the secondary transfer device (secondary transfer roll 93) and transferred onto the recording material 95 as the intermediate transfer belt 90 rotates.

A cleaning process for collecting waste toner in such an image forming process will be described in detail.
First, in the primary transfer, residual toner remaining on the photosensitive drum 72 without being transferred to the intermediate transfer belt 90 is collected by the photosensitive member cleaner 76.
When the transfer of each color toner on the photosensitive drum 72 is completed, the control device (not shown) receives information on the write timing of the exposure device and performs a counter counting operation. As a result, if the set number of sheets has been reached, the mode is switched to a transfer mode in which the waste toner is transferred to the intermediate transfer belt 90, and the waste toner transfer body 81 transfers the waste toner in the photoreceptor cleaner 76 to the inter image of the intermediate transfer belt 90. To 61.

Further, when the secondary transfer is completed, the residual toner of the toner image remaining on the intermediate transfer belt 90 and the waste toner of the inter image 61 are collected at once by the belt cleaner 94.
Also in such a tandem type image forming apparatus, the residual toner on the photosensitive drum 72 and the intermediate transfer belt 90 can be effectively collected by the photosensitive member cleaner 76 and the belt cleaner 94.
In this embodiment, the intermediate transfer belt 90 is used. However, the present invention is not limited to this and can be applied to an embodiment using a recording material conveyance body.

It is explanatory drawing which shows the cleaning apparatus which concerns on this invention. 1 is an explanatory diagram showing Embodiment 1 of an image forming apparatus to which the present invention is applied. In the image forming apparatus according to the first embodiment, (a) and (b) are explanatory views showing the layout and operation of the photoreceptor cleaner. In the image forming apparatus according to the first embodiment, (a) is an explanatory diagram showing connection of a power supply bias, and (b) is an explanatory diagram showing an action of a transition electric field. 3 is an explanatory diagram showing a flowchart of a control device in the image forming apparatus according to Embodiment 1. FIG. 3 is an explanatory diagram showing an interimage on an intermediate transfer belt in the image forming apparatus according to Embodiment 1. FIG. In the image forming apparatus according to the first modification of the first embodiment, (a) is an explanatory diagram showing connection of power supply bias, and (b) is an explanatory diagram showing the action of a transition electric field. FIG. 10 is an explanatory diagram illustrating connection of power supply biases in an image forming apparatus according to a second modification of the first embodiment. In the image forming apparatus according to Embodiment 2, (a) and (b) are explanatory views showing the layout and operation of the photoreceptor cleaner. FIG. 10 is a perspective view showing a driving mechanism of a photoconductor cleaner in an image forming apparatus according to Embodiment 3. In the image forming apparatus according to Embodiment 3, (a) shows a side view of the photoreceptor cleaner, and (b) shows a front view of the photoreceptor cleaner. It is explanatory drawing which shows Embodiment 4 of the image forming apparatus to which this invention was applied.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Image carrier, 2 ... Image carrier; Intermediate transfer body, 3 ... Image carrier cleaning device, 4 ... Image carrier cleaning device, 5 ... Collection housing, 5a and 5b ... Opening, 6 ... Cleaning member, 7 ... Waste toner Transition body, 8 ... accommodating housing, 9 ... cleaning member

Claims (10)

In an image forming apparatus of an aspect in which a toner image formed on an image carrier is transferred to a recording material using an image carrier,
An image carrying cleaning device for collecting waste toner remaining on the image carrier, and an image carrying cleaning device for collecting waste toner remaining on the image carrier,
An image carrier cleaning device is disposed opposite the image carrier and the image carrier, and a collection housing that temporarily collects waste toner;
A cleaning member provided in the recovery housing and removing waste toner remaining on the image carrier and storing the toner in the recovery housing;
Waste toner transfer that is provided in the collection housing and contacts the image carrier at a timing at which the toner image formed on the image carrier is not damaged, and transfers the waste toner stored in the collection housing to the image carrier. An image forming apparatus comprising: a body. The image forming apparatus according to claim 1.
The waste toner transfer body is movably supported by a retracting means, and moves between a contact position contacting the image transport body and a separated position separating from the image transport body. . The image forming apparatus according to claim 2.
The retracting means swings and supports a waste toner transfer body. The image forming apparatus according to claim 1.
An image forming apparatus, wherein the waste toner transfer member is rotatable when contacting the image carrier. The image forming apparatus according to claim 4.
The image forming apparatus, wherein the waste toner transfer member has a rotation speed substantially equal to the rotation speed of the image carrier when contacting the image carrier. The image forming apparatus according to claim 1.
The waste toner transfer body is provided with a transition electric field forming means, and causes the waste toner transfer electric field by the transfer electric field forming means to act on the image carrier at the time of contact with the image carrier. apparatus. The image forming apparatus according to claim 1.
The waste toner transfer body is in contact with a non-image forming area located between image forming areas on an image carrier. The image forming apparatus according to claim 1.
An image forming apparatus, wherein the waste toner transfer member contacts the image carrier in a cleaning cycle different from the image forming cycle. The image forming apparatus according to claim 1.
An image forming apparatus, wherein the image carrier is an intermediate transfer member.   A cleaning device used as an image carrier cleaning device in the image forming apparatus according to claim 1.

Images