JP2003186364A - Image forming device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image forming device having a space saving and low cost cleaning device, capable of efficiently preventing the color mixture of toner or the stains of an electrifier, without greatly modifying the constitution of a conventional image forming device and with a simple constitution. <P>SOLUTION: In the image forming device, the cleaning device having a scraping member which scrapes residual toner off the surface of a photoreceptor after transferring a toner image to an intermediate transfer body and a housing which includes an opening directed to the surface of the intermediate transfer body and which houses the scraping member is provided. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrophotographic image forming apparatus such as a copying machine, a laser beam printer, and an electrostatic recording device.

[0002]

2. Description of the Related Art Conventionally, copying machines, laser beam printers,
In an electrophotographic image forming apparatus such as a facsimile or an electrostatic recording device, a rotating photoconductor is charged by a charger and then exposed by a writing unit to form an electrostatic latent image. Is developed by developing means to form a toner image. Then, this toner image is transferred to a medium such as recording paper directly or through an intermediate transfer body, and the toner image on the recording paper is fixed by a fixing device to form an image on the recording paper. On the other hand, so-called residual toner remaining on the photoconductor without being transferred to a recording paper or an intermediate transfer body is removed by a cleaning unit to prepare for the next image forming process.

As a cleaning means for removing the residual toner, a cleaning blade which is made of a plate-like elastic rubber and mechanically removes the toner by bringing the elastic rubber into contact with the surface of the photosensitive member is widely known. (JP-A-60-101575, JP-A-63-2491)
83).

Generally, the means for cleaning the residual toner on the photosensitive member is closely related to the charging means for charging the photosensitive member. In an image forming apparatus using a non-contact type charger that discharges a large amount of electricity or a contact type charger that uses an AC power source, not only toner but also ozone that is generated by discharge and adheres to the surface of the photoconductor causes image quality defects. A cleaning blade is also particularly effective because it also has the effect of exposing the clean surface of the photoconductor by scraping it off together with nitrogen oxide together with the photoconductor surface layer.

However, this method has the drawback of shortening the life of the photoconductor because the surface is abraded. In particular, the contact type charger using an AC power source has a problem that the wear of the photoreceptor is particularly remarkable because a severe discharge is generated between the surface of the photoreceptor and the charger.

On the other hand, fur brushes and sponge pads are also known as cleaning means other than the cleaning blade. However, the method using a fur brush or a sponge pad solves the problem of photoconductor wear, but it is necessary to remove the toner adhering to itself with a flick cover or the like, and then suction the toner with a vacuum or a fan. Therefore, there is a problem that a large space is required, the size of the device becomes large, and the cost becomes high.

Japanese Patent Publication No. 1-60148 discloses a technique of electrostatically collecting the toner adhering to the fur brush by contacting the fur brush with a collecting roller applied with a bias voltage. Whichever method such as a cleaning blade, a fur brush, a sponge pad, etc. is used, a collecting means for collecting the toner removed from the surface of the photoconductor in a toner box or the like is required. Therefore, it is necessary to secure a space for that purpose and to bear the cost, especially in a tandem type image forming apparatus.

In recent years, in view of environmental problems, a contact type charger using a DC power source with a small discharge amount has been spotlighted, and a cleaning means using a fur brush or a sponge pad without using a cleaning blade has been reviewed.
Further, in order to secure dot reproducibility and uniform chargeability, there is a tendency to use spherical toner having good releasability. Therefore, an image forming apparatus that does not use any cleaning means has been developed.

However, the contact type charger using a direct current power source is vulnerable to contamination by toner and the like, and the present situation is that the residual toner must be removed by a light contacting conductive fur brush or the like.

On the other hand, in order to meet the demand for downsizing of the apparatus, cleaning is performed in which toner is temporarily stored in the brush or pad and a reverse bias is periodically applied to the stored toner to return the toner from the brush or pad onto the photosensitive member. A method is known in which a waste toner recovery route is omitted by performing a cycle.

However, in this method, a part of the toner returned from the brush or the like to the photoconductor is attracted to the charger side at the charging position where the photoconductor comes into contact with the charger, so that the charger uses toner. There is a problem that the toner is contaminated, the charging efficiency is lowered, and the color toners are mixed.

[0012]

SUMMARY OF THE INVENTION In view of the above circumstances, the present invention is effective in preventing color mixture of toner and contamination of a charging device with a simple structure without making a great change to the structure of an existing image forming apparatus. It is an object of the present invention to provide an image forming apparatus equipped with a cleaning device that can be effectively prevented and is space-saving and low-cost.

[0013]

SUMMARY OF THE INVENTION An image forming apparatus of the present invention which achieves the above object comprises a photoreceptor on which a toner image is formed, and an intermediate transfer body which receives the transfer of the toner image from the surface of the photoreceptor. And a toner image on the intermediate transfer member,
In an image forming apparatus that finally forms an image of a fixed toner image on a recording medium by transferring and fixing the toner image on the recording medium, the surface of the photoreceptor after the toner image is transferred to the intermediate transfer body. The cleaning device is provided with a scraping member for scraping off the residual toner and a housing for housing the scraping member, which is opened toward the surface of the intermediate transfer member.

Here, it is preferable that the cleaning device always discharges the residual toner scraped from the surface of the photosensitive member by the scraping member from the opening of the housing.

Further, the scraping member is a cleaning brush that scrapes residual toner from the surface of the photoconductor by rotating in a predetermined direction, and the cleaning device further contacts the cleaning brush to remove the residual toner. It is preferable to have a flicker bar for removing the toner.

Further, the scraping member may be a plate-like cleaning blade having a tip portion in contact with the surface of the photoconductor, and scrapes residual toner from the surface of the photoconductor at the tip portion. Good.

The image forming apparatus of the present invention which achieves the above object comprises a photoconductor on which a toner image is formed, and a conveyor belt which carries and conveys a recording medium, and is formed on the photoconductor. In the image forming apparatus, the toner image is transferred onto the recording medium conveyed by the conveying belt and fixed on the recording medium to form an image of the fixed toner image on the recording medium. A cleaning device having a scraping member for scraping off the residual toner from the surface of the photoconductor after the transfer of the toner image, and a housing for housing the scraping member, which is opened toward the surface of the conveyor belt. Is characterized by.

Here, the cleaning device is provided with a shutter for opening and closing the opening, and by opening and closing the shutter in accordance with the interval, the opening of the housing is provided on the surface of the conveyor belt and on the conveyor belt. It is also a preferable embodiment that the recording medium is discharged to a portion other than the portion where it is carried.

[0019]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the image forming apparatus of the present invention will be described below. FIG. 1 is a schematic configuration diagram showing an image forming apparatus according to a first embodiment of the present invention. In the image forming apparatus shown in FIG. 1, the photosensitive member 1 on which toner images of Y (yellow), M (magenta), C (cyan), and K (black) are formed while rotating in the direction of arrow A Are arranged in series, and each of the four photoconductors 1 includes a driving roll 11, a driven roll 12, and an opposing roll 13.
It is in contact with the intermediate transfer belt 10 which is laid over and circulates in the direction of arrow B. Each photoconductor 1 is provided with a charging device 2, an exposing device 3, a developing device 4, and a cleaning device 5. Each of the photoconductors 1 is uniformly charged by the charger 2 while rotating in the direction of the arrow A, and the uniformly charged photoconductor 1 is exposed by the exposure device 3 and modulated based on the image signal separated into each color. The electrostatic latent image is formed by irradiating the beam, and the photoconductor 1 on which the electrostatic latent image is formed is developed with the toner of each color by the developing device 4 to form the toner image of each color.

Here, in the developing device 4, spherical toner is used in order to improve dot reproducibility and uniform charging property by stirring.

The four photoconductors 1 on which the toner images of YMCK colors are formed are in contact with the intermediate transfer belt 10 at each transfer position, and each primary transfer is opposed to each photoconductor 1 with the intermediate transfer belt 10 interposed therebetween. The toner images of Y, M, C, and K colors are superimposed and transferred onto the intermediate transfer belt 10 at the timing when the toner images of Y, M, C, and K colors are rotated by the rolls 6, respectively.
The intermediate transfer belt 10 onto which all the YMCK color toner images have been superposed and transferred cyclically moves in the direction of arrow B, and the superposed YM
The CK color toner image is secondarily transferred onto the sheet P conveyed from the sheet tray 15 by the secondary transfer roll 14 that faces the facing roll 13 with the intermediate transfer belt 10 interposed therebetween. The sheet P onto which the YMCK color toner image has been transferred is heated and pressed by the fixing device 16, and an image including the fixed toner image is formed on the sheet P.

At the position where the toner image formed on the photoconductor 1 is brought into contact with the surface of the photoconductor 1 after the primary transfer onto the intermediate transfer belt 10, the toner remaining on the surface of the photoconductor 1 is scraped off. A cleaning device 5 having a member and a housing that houses the scraping member and has an opening toward the surface of the intermediate transfer member is provided. The cleaning device 5 is
The toner scraped off the surface of the photoconductor 1 by the scraping member,
The surface of the photoreceptor 1 is cleaned by constantly discharging it from the opening of the housing to the surface of the intermediate transfer belt 10 to prepare for the next image forming cycle. In addition, the intermediate transfer belt 10
The toner remaining on the intermediate transfer belt 10 after the secondary transfer from the sheet P to the sheet P is cleaned by the belt cleaning device 17.

Since the toner image formed on the photosensitive member 1 is formed of, for example, a toner having a negative polarity, the toner image is attracted by the transfer electric field applied from the primary transfer roll 6 and the intermediate transfer belt 10 is attracted. Adsorbed on top.
However, since the toner scraped off the surface of the photoconductor 1 is a positive toner having a reversed polarity or a toner having no electric charge, it is discharged from the opening of the housing to the surface of the intermediate transfer belt 10 and the intermediate transfer is performed. Even if the toner adheres to the belt 10 in a cloud shape, the polarity is different from the polarity of the transferred toner image adsorbed on the intermediate transfer belt 10. Therefore, even if the toner image transferred by the transfer electric field applied by the secondary transfer roll 14 is attracted to the paper P, the toner adhered in a cloud shape having different polarities is not attracted to the paper P by the transfer electric field. . Therefore, the toner adhered in a cloud shape is collected together with the transfer residual toner not transferred to the paper P by the belt cleaning device 17 provided on the downstream side of the secondary transfer roll 14 in the circulating direction B of the intermediate transfer belt 10. It

Here, the photosensitive member 1 has a diameter of 30 mm.
The cylindrical photoreceptor of is used, and the surface layer of the photoreceptor 1 is
An organic photoreceptor having a sensitivity in the infrared region, which is composed of a polymer resin having polycarbonate as a binder and a triphenylamine-based charge transport agent, is used, but is not limited thereto.

Further, as the charging device 2, a contact charging device made of a conductive rubber formed in a roll shape is used, and it is -1000V.
The surface of the photoconductor 1 is charged to −350 V by applying a DC voltage of about a certain degree, and the surface of the photoconductor 1 is irradiated with an exposure beam to form an electrostatic latent image, and subsequently, is negatively charged by the developing device 4. The developed toner is developed. The developed toner image is transferred to the intermediate transfer belt 1 by the primary transfer roll 6.
After being transferred to 0, it is transferred to the paper P by the secondary transfer roll 14 and fixed by the fixing device 16.

Since the photosensitive member 1 of this embodiment is not provided with a charge adjusting member such as a pre-cleaning corotron, the residual toner on the photosensitive member 1 after the primary transfer is slightly changed from near zero charge amount. It is distributed on the plus side. Therefore, the cleaning performance can be improved by applying a DC bias voltage of about -400 V to the scraping member of the cleaning device 5 so that discharge does not occur.

FIG. 2 is an enlarged view of the periphery of the photoconductor showing the sectional structure of the cleaning device used in the image forming apparatus of the first embodiment.

In FIG. 2, the photosensitive member 1 and the primary transfer roll 6 are opposed to each other with the intermediate transfer belt 10 interposed therebetween. The photoconductor 1 is provided with an exposure device 3 for irradiating an exposure beam, and a developing device 4 for developing the electrostatic latent image formed on the photoconductor 1 with a developing roller 4a arranged close to the photoconductor 1 with toner. In addition, the housing 2b of the charger 2 that charges the photoconductor 1 and the housing 5b of the cleaning device 5 are configured to be common, and the housings 2b and 5b include the charger 2 and the cleaning device 5 that are housed therein. It is arranged at a position upstream of the exposure device 3 in the rotation direction A of the body 1 so as to come into contact with the photoconductor 1.

Although the housing 2b of the charger 2 and the housing 5b of the cleaning device are separated from each other, the cleaning device 5 is arranged so that toner does not scatter from the housing 5b of the cleaning device 5 to the housing 2b of the charger 2.
A seal is provided in the housing 5b. Further, the housing of the cleaning device 5 is the intermediate transfer belt 1
The opening 8 faces the surface 0.

The cleaning device 5 is a scraping member that rotates in the same direction C as the photoconductor 1 and scrapes the transfer residual toner from the surface of the photoconductor 1, and the cleaning brush 5a and the residual toner from the surface of the photoconductor 1. It is provided with a flicker bar 5c fixed in the housing 5b, which comes into contact with the cleaning brush 5a after scraping and wipes off the toner from the cleaning brush 5a. In order for the toner to be blown downward by the recoil caused by the flicker bar 5c, the cleaning brush 5a rotates in the direction of arrow C and the peripheral speed is made faster than that of the photoconductor. Some of the toner removed by the flicker bar 5c temporarily stays in the housing 5b, but most of it is discharged onto the intermediate transfer belt 10 from the opening 8 of the housing 5b each time.

The cleaning device 5 keeps the photosensitive member 1 rotating in the direction of arrow A for performing the image forming process.
The cleaning brush 5a scrapes off the residual toner on the surface of the photoreceptor 1, and the scraped toner is
The surface of the photoconductor 1 is cleaned by constantly discharging it from the housing 5b onto the surface of the intermediate transfer belt 10 to prepare for the next image forming process.

A bias voltage may be applied to the cleaning brush 5a from a power source (not shown). Further, the developing device 4 uses a spherical toner having a shape factor of 120 and a particle size of about 6 μm, which is formed by a polymerization method, but is not necessarily limited to this.

As described above, since the image forming apparatus of this embodiment uses the spherical toner and the intermediate transfer belt,
A high primary transfer efficiency can be realized, and the transfer residual toner remaining on the surface of the photoconductor 1 with which the cleaning device 5 contacts can be suppressed to 0.04 g / m ² or less. Therefore, the toner scraped off from the surface of the photoconductor 1 by the cleaning brush 5a is flicker bar 5c.
As a result, the toner 9 is easily removed from the cleaning brush 5a, is discharged from the opening 8 of the housing 5b to the surface of the intermediate transfer belt 10, and becomes the toner 9 accumulated in a cloud shape. Since the primary transfer efficiency is high and the amount of residual toner is small, and toner having a high sphericity is used, most of the toner is discharged from the cleaning brush 5a onto the intermediate transfer belt 10 by one flicking.

Next, an image forming apparatus according to the second embodiment of the present invention will be described.

The second embodiment is different from the first embodiment in the scraping member of the cleaning device, but is the same in all other respects. Therefore, the difference will be described.

FIG. 3 is an enlarged view of the periphery of the photoconductor showing the sectional structure of the cleaning device used in the image forming apparatus of the second embodiment.

In FIG. 3, the photosensitive member 1 and the primary transfer roll 6 are opposed to each other with the intermediate transfer belt 10 interposed therebetween. The photoconductor 1 is provided with an exposure device 3 for irradiating an exposure beam, and a developing device 4 for developing the electrostatic latent image formed on the photoconductor 1 with a developing roller 4a arranged close to the photoconductor 1 with toner. Further, the charger 2 for charging the photoconductor 1 and the cleaning device 5 are both housed in the same housing 2b, 5b, and are arranged at positions in contact with the photoconductor 1, respectively.

The housing 2b of the charger 2 and the housing 5b of the cleaning device 5 are separated from each other, and the housing 5b of the cleaning device 5 is opened with the surface of the intermediate transfer belt facing.

The cleaning device 5 includes a cleaning blade 5f made of a thin metal plate for scraping the residual toner from the surface of the photoconductor 1 by bringing the tip thereof into contact with the surface of the photoconductor 1, and the photoconductor 1
Is installed in the vicinity of the opening 8 of the housing 5b of the cleaning device 5 and the cleaning brush 5g which rotates in the same direction A as the above and carries the residual toner scraped by the cleaning blade 5f to the opening 8 facing the surface of the intermediate transfer belt 10. A flicker bar 5 that removes toner from the cleaning brush 5g by the reaction force generated by the rotation of the cleaning brush 5g.
and h.

Here, as the cleaning blade 5f, a SUS plate having a thickness of 100 μm is attached at a mounting angle of 17 degrees and a biting amount of 0.
Although the thickness is 5 mm, it is not necessarily limited to a metal plate such as a SUS plate, and urethane or the like may be used.

A spherical toner having a shape factor of 120 and a particle diameter of about 6 μm, which is formed by a polymerization method, is used as the toner.

In the cleaning device 5 of the present embodiment, since the scraping member for scraping off the residual toner is the cleaning blade 5f made of a thin metal plate, the overcoat layer of the photosensitive member 1 is cleaned while being scraped by a very small amount. The cleaning property is dramatically improved, and the dirt on the charger 2 can be further reduced.

Next, the test results for confirming the cleaning effect of the image forming apparatus of the first embodiment and the second embodiment will be described. For comparison, the same confirmation test is performed on an image forming apparatus using a conventionally used cleaning cycle method.

FIGS. 4 and 5 show toner adhesion to the charger when continuous printing is performed using the image forming apparatus of the first and second embodiments and the image forming apparatus of the comparative example. FIG. 3 is a diagram showing a change in amount and a change in charging potential of a photoconductor.

In FIGS. 4 and 5, the vertical axis represents the toner adhesion amount (g / m ² ) or the charging potential of the photoconductor (−V), and the horizontal axis represents the cumulative number of prints (A4 size: 1,000). .

In the graph in the figure, □ indicates a cleaning cycle type image forming apparatus for applying a reverse bias to a conventional cleaning brush to return toner to the photoconductor, and × indicates a cleaning brush. In the image forming apparatus of the first embodiment, the ● marks indicate the amount of toner attached to the charger or the charging of the photoconductor for every 20 continuous prints in each of the image forming apparatuses of the second embodiment using the cleaning blade. The result of having measured the electric potential is shown.

As can be seen from the graph, in the image forming apparatuses of the first and second embodiments, the amount of toner adhered to the charger is smaller and the image forming apparatus of the second embodiment is smaller than the cleaning cycle type image forming apparatus. Since the amount of change in the charging potential of the body is small, it is confirmed that the charging device is much less dirty, and it can be seen that the function of preventing dirt is high.

The image forming apparatuses according to the first and second embodiments use the intermediate transfer belt, the scraped toner is immediately discharged to the intermediate transfer belt, and the residual toner itself is Since the amount is small, the residual toner discharged to the intermediate transfer belt is a reverse polarity toner. Therefore, even when the toner image transferred to the intermediate transfer belt is secondarily transferred onto the paper, the residual toner does not transfer to the paper and moves on the intermediate transfer belt as it is, and is collected by the belt cleaning device 17. Therefore, the image formed on the paper does not cause an image quality defect due to the residual toner.

Here, when the density of the background fog was measured using several standard PPC papers, the residual toner discharged from the cleaning devices of the image forming apparatuses of the first and second embodiments. It has been confirmed that the increase in the background fog due to (4) is suppressed to a maximum of about 0.015D for each color and there is no problem.

Therefore, when the residual toner scraped by the cleaning device of the image forming apparatus of the first and second embodiments is discharged to the intermediate transfer belt, it is necessary to discharge the residual toner selectively to the non-image area. Instead, the discharging operation can be continuously performed during the operation of the image forming apparatus. Therefore, high-quality timing control is unnecessary,
A space-saving and low-cost cleaning device can be realized.

However, when a large amount of untransferred toner rushes into the cleaning device due to an abnormal process such as paper jam, a cleaning process is performed for several seconds in advance when returning from the abnormal process, and a large amount of toner is transferred to the intermediate transfer belt. Need to be discharged and collected by the belt cleaning device 17.

Next, an image forming apparatus according to the third embodiment of the present invention will be described.

In the third embodiment, as compared with the second embodiment, the image forming apparatus is a tandem type in which a paper transport belt is used, and the cleaning device is configured to transfer the paper transported on the paper transport belt. The difference is that residual toner is discharged between the sheets.

FIG. 6 is a schematic block diagram showing the image forming apparatus of the third embodiment.

The image forming apparatus shown in FIG. 6 rotates in the direction of arrow A, and is Y (yellow), M (magenta),
Four photoconductors 1 on which toner images of C (cyan) and K (black) are formed are arranged in series. Each of the four photoconductors 1 includes a driving roll 11 and a driven roll 1.
It is in contact with the sheet conveying belt 18 which is laid over the sheet 2 and circularly moves in the direction of arrow B. Each photoreceptor 1 has a charger 2,
An exposing device 3, a developing device 4, and a cleaning device 5 are provided. Each of the photoconductors 1 is uniformly charged by the charger 2 while rotating in the direction of the arrow A, and the uniformly charged photoconductor 1 is exposed by the exposure device 3 and modulated based on the image signal separated into each color. The electrostatic latent image is formed by irradiating the beam, and the photoconductor 1 on which the electrostatic latent image is formed is developed with the toner of each color by the developing device 4 to form the toner image of each color.

Here, in the developing device 4, spherical toner is used in order to improve dot reproducibility and uniform charging property by stirring.

The four photoconductors 1 on which the toner images of YMCK colors are formed are in contact with the paper transport belt 18 at the respective transfer positions, and face the photoconductor 1 and the transfer roll 6 with the paper transport belt 18 interposed therebetween. There is. Paper transport belt 18
The paper P taken out from the paper tray 15 is carried on the paper and is conveyed to each transfer position. The four photoconductors 1 on which the toner images of Y, M, C, and K colors are formed are rotating in a predetermined direction, and the formed toner images are conveyed by the sheet conveying belt 18 when rotated to the transfer position. Each timing is adjusted so that it is transferred on top. Then, the toner images of Y, M, C, and K colors are sequentially and multiple-transferred onto one sheet on the conveyor belt. The sheet P on which all the YMCK color toner images have been superposed and transferred is heated and pressed by the fixing device 16, and an image composed of the fixed toner image is formed on the sheet P.

The toner image formed on the photoconductor 1 is printed on the paper P.
After the transfer to the surface of the photoconductor 1 before transferring to the next image forming cycle, a scraping member for scraping off the residual toner on the surface of the photoconductor 1 and an opening toward the surface of the sheet conveying belt 18 are opened. , A cleaning device 5 having a housing that houses the scraping member. The cleaning device 5 includes a sheet transport belt 1 on the surface of the sheet transport belt 18 that transports the toner scraped off the surface of the photoconductor 1 by the scraping member while carrying the sheet P from the opening of the housing.
The surface of the photoconductor 1 is cleaned by discharging the paper P onto the area other than the area where the paper P is carried on the paper 8 to prepare for the next image forming cycle. Further, the toner on the paper transport belt 18 is cleaned by the belt cleaning device 17.

Here, the cleaning device 5 of the present embodiment
A shutter (not shown) is provided in the opening of the housing. The shutter is opened and closed by the cleaning device 5 in response to a signal from the control unit 20 that controls the image forming interval of the image forming apparatus, and the portion of the sheet conveying belt 18 excluding the portion on which the sheet P is carried, for example, the sheet. When a plurality of sheets are carried, the toner is discharged between the sheets.

FIG. 7 is an enlarged view of the periphery of the photoconductor showing the sectional structure of the cleaning device used in the image forming apparatus of the third embodiment.

In FIG. 7, the photoconductor 1 and the transfer roll 6 are opposed to each other with the paper transport belt 18 interposed therebetween. Photoconductor 1
Is provided with an exposure device 3 for irradiating an exposure beam, and a developing device 4 for developing the electrostatic latent image formed on the photoconductor 1 with a developing roller 4a arranged close to the photoconductor 1 with toner. The charger 2 for charging the photoconductor 1 and the cleaning device 5 are both housed in the same housing 2b, 2a,
Each is arranged at a position in contact with the photoconductor 1.

The housing 2b of the charger and the housing 5b of the cleaning device 5 are separated from each other, and the housing 5b of the cleaning device 5 is opened with the surface of the paper transport belt 18 facing. The opening 8 is provided with a shutter 5e.

The cleaning device 5 is a cleaning blade 5 made of a thin metal plate which is a scraping member for scraping the residual toner from the surface of the photoconductor 1 by bringing the tip thereof into contact with the surface of the photoconductor 1.
f and the residual toner scraped off by the cleaning blade 5f rotated in the direction A opposite to the photoconductor 1,
Cleaning brush 5 that carries to the opening 8 facing the surface of 8
g, and a flicker bar 5h that is attached near the opening 8 of the housing 5b of the cleaning device 5 and removes toner by the reaction force of rotation of the cleaning brush 5g. The toner blown off into the housing by the reaction force of the flicker bar 5h is discharged to a portion other than the portion where the sheet P is carried on the sheet conveyance belt 18 by opening and closing the shutter 5e provided in the opening 8 of the housing 5b. Is released. The shutter is opened and closed by the cleaning device 5 in response to a signal from the control unit 20 that controls the image forming interval of the image forming apparatus.

In the cleaning device 5 of this embodiment, since the scraping member 7 for scraping off the residual toner is the cleaning blade 5f made of a thin metal plate, the cleaning is carried out while shaving the overcoat layer of the photoconductor 1 by a very small amount. Therefore, the cleaning property is dramatically improved, and the dirt on the charger 2 can be further reduced.

[0065]

According to the image forming apparatus of the present invention, since the cleaning device discharges the residual toner scraped from the surface of the photoconductor to the outside of the cleaning device without returning the toner to the photoconductor, stains and color mixture on the charger may occur. Dramatically reduced. Further, since the residual toner discharged to the outside of the cleaning device is collected by the belt cleaning device, a mechanism for transporting the toner to the BOX or the developing device is not required, and the space can be saved.

Further, in the case of the image forming apparatus using the intermediate transfer member, the probability that the residual toner constantly discharged from the opening of the cleaning device is placed on the paper can be extremely reduced without providing a special mechanism. Even in the case of an image forming apparatus that uses a sheet conveyance belt, if a simple shutter or the like is provided in the opening of the cleaning device, opening and closing of the shutter causes, for example, residual toner that is discharged between sheets and remains on the sheet. Since the probability can be reduced, the cost of the cleaning device can be reduced.

[Brief description of drawings]

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

FIG. 2 is an enlarged view of the periphery of a photoconductor showing a cross-sectional structure of a cleaning device used in the image forming apparatus of the first embodiment.

FIG. 3 is an enlarged view of the periphery of a photoconductor showing a cross-sectional structure of a cleaning device used in the image forming apparatus of the second embodiment.

FIG. 4 is a diagram showing changes in the amount of toner adhered to a charger when continuous printing is performed using the image forming apparatuses of the first and second embodiments and the image forming apparatus of the comparative example. Is.

FIG. 5 is a diagram showing a transition of a charging potential of a photoconductor when continuous printing is performed using the image forming apparatuses of the first and second embodiments and an image forming apparatus of a comparative example. .

FIG. 6 is an enlarged view showing the vicinity of the cleaning device according to the second embodiment of the present invention.

FIG. 7 is an enlarged view of the periphery of a photoconductor showing a sectional structure of a cleaning device used in the image forming apparatus according to the third embodiment.

[Explanation of symbols]

1 photoconductor 2 charger 2b, 5b housing 3 exposure equipment 4 Developing device 4a Developing roll 5 Cleaning device 5a cleaning brush 5c, 5h Flicker bar 5e shutter 5f cleaning blade 5g cleaning brush 6 Primary transfer roll 8 openings 9 toner 10 Intermediate transfer belt 11 drive roll 12 Driven roll 13 Opposite roll 14 Secondary transfer roll 15 paper tray 16 Fixing device 17 Belt cleaning device 18 Paper transport belt 20 Control unit

Continued front page    (72) Inventor Yoshikazu Okamoto             Fuji Zero, 2274 Hongo, Ebina City, Kanagawa Prefecture             Co., Ltd. Ebina Office F-term (reference) 2H134 GA01 GA06 GA10 GB02 HB01                       HB13 HD01 HD19 JA01 KB01                       KD02 KD08 KF06 KF09 KG04                       KH03 KH07 KH09 KJ02                 2H200 GA12 GA23 GA44 GA47 GB12                       GB13 GB22 HA02 HB12 HB22                       JA02 JB06 JB16 JB32 JB42                       JC03 JC12 LB02

Claims (7)

[Claims] 1. A photosensitive member having a toner image formed on its surface, and an intermediate transfer member for transferring the toner image from the surface of the photosensitive member. The toner image on the intermediate transfer member is finally recorded. In an image forming apparatus that forms an image of a fixed toner image on a recording medium by transferring and fixing the toner image on a medium, residual toner is transferred from the surface of the photoconductor after the toner image is transferred to the intermediate transfer body. An image forming apparatus comprising: a cleaning device having a scraping member for scraping and a housing for housing the scraping member, the housing being opened toward the surface of the intermediate transfer member. 2. The image forming apparatus according to claim 1, wherein the cleaning device constantly discharges the residual toner scraped from the surface of the photoconductor by the scraping member from the opening of the housing. apparatus. 3. The scraping member is a cleaning brush that scrapes residual toner from the surface of the photoconductor by rotating in a predetermined direction, and the cleaning device further contacts the cleaning brush. The image forming apparatus according to claim 1, further comprising a flicker bar for removing the toner. 4. The scraping member is a plate-shaped cleaning blade whose tip is in contact with the surface of the photoconductor, and scrapes residual toner from the surface of the photoconductor with the tip. The image forming apparatus according to claim 1, wherein the image forming apparatus is an image forming apparatus. 5. A photosensitive member on which a toner image is formed, and a conveyor belt for carrying and conveying a recording medium, the toner image formed on the photosensitive member being conveyed by the conveyor belt. An image forming apparatus for forming an image composed of a fixed toner image on a recording medium by transferring the toner image onto the recording medium and fixing the image on the recording medium, the image forming apparatus comprising: An image forming apparatus comprising: a cleaning device having a scraping member that scrapes residual toner from a surface, and a housing that opens toward the surface of the conveyor belt and that houses the scraping member. 6. The cleaning device carries a residual toner scraped from the surface of the photosensitive member by the scraping member, from the opening of the housing, and carries a recording medium on the surface of the conveyor belt on the conveyor belt. The image forming apparatus according to claim 5, wherein the image is emitted to a portion excluding a portion. 7. The cleaning device includes a shutter that opens and closes the opening, and opens and closes the shutter according to the interval to record from the opening of the housing onto the surface of the conveyor belt on the conveyor belt. The image forming apparatus according to claim 5, wherein the medium is discharged to a portion other than a portion where the medium is carried.