JPH0844266A - Image forming device - Google Patents

Abstract

PURPOSE:To satisfactorily clean a recording material carrying member and to obtain an excellent image by providing the width in a thrust direction to the sheet-like cleaning member and the pressing member over the oscillation width of the recording material carrier member oscillating in the direction at right angles to the turning direction by the turning of the recording material carrier member. CONSTITUTION:The width of the cleaning web 19 for cleaning the transporting belt 130 is made wider than the width to permit the presence of the transport belt 130 by the oscillation corresponding to the turning, and the width of the pressing roller 22 for pressing the cleaning web 19 to the transporting belt 130 is made wider than the width of the cleaning web 19. Thus, the cleaning performance of the cleaning web 19 with respect to the transporting belt 130 can be stably maintained, and the transporting belt 130 is satisfactorily cleaned to the end part of both side. Moreover, not only the toner sticking on the transporting belt 130, but also the releasing agent oil of the screen image forming time are satisfactorily removed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image forming apparatus such as a copying machine or a laser beam printer, and more particularly to an image forming apparatus capable of forming a multicolor image on both sides of a recording material.

[0002]

2. Description of the Related Art Conventionally, a plurality of image forming sections are provided, toner images of different colors are formed in the respective image forming sections, and the toner images are sequentially superimposed and transferred onto the same recording material to form a color image. Various color image forming apparatuses have been proposed.

In such a color image forming apparatus,
Usually, toner, mold release agent oil, dust, and other foreign matter are formed on an image carrier that forms a toner image and carries the toner image, and a recording material carrying member that carries a recording material and guides it to a transfer portion of the image carrier. Adhere to the recording material, which may contaminate the recording material. Therefore, it is necessary to clean these foreign matters.

This cleaning performance requires a higher level when the speed of the image forming apparatus is increased, or when the amount of the release agent oil used is increased by using a sharp melt type toner described later.

Under such circumstances, a multicolor electrophotographic color copying machine using an endless recording material carrying member is used for high speed recording.

An example of such a color electrophotographic recording apparatus is shown in FIG.
Briefly based on, the first, second,
Third and fourth image forming portions Pa, Pb, Pc, and Pd are arranged in parallel, and toner images of different colors are formed through the processes of latent image, development, and transfer.

The image forming portions Pa, Pb, Pc and Pd are
Each of the photosensitive drums 3 is provided with a dedicated image carrier, in this example, the electrophotographic photosensitive drums 3a, 3b, 3c and 3d.
A toner image of each color is formed on a, 3b, 3c and 3d. A recording material carrying member (conveying belt) 130 is installed adjacent to each of the photosensitive drums 3a to 3d.
The toner images of the respective colors formed on b, 3c, and 3d are transferred onto the recording material P carried on the carrying belt 130 and carried. Further, the recording material P on which the toner image of each color is transferred is
After fixing the toner image by heat and pressure in the fixing unit 9,
The recorded image is discharged outside the apparatus.

Exposure lamps 111a, 111b and 11 are provided on the outer circumferences of the photosensitive drums 3a, 3b, 3c and 3d, respectively.
1c and 111d, drum chargers 2a, 2b, 2c and 2d, potential sensors 113a, 113b, 113c and 113d, developing devices 1a, 1b, 1c and 1d, brush transfer chargers 24a, 24b, 24c and 24d, and cleaner 4a. 4b, 4c and 4d are provided, and a light source device and a polygon mirror 11 (not shown) are further provided in the upper part of the device.
7 is installed.

The polygon mirror 117 is rotated to scan the laser light emitted from the light source device, the light flux of the scanning light is deflected by the reflection mirror, and the fθ lens is used to generate a light beam on the generatrix of the photosensitive drums 3a, 3b, 3c and 3d. A latent image corresponding to an image signal is formed on the photosensitive drums 3a, 3b, 3c, and 3d by condensing and exposing.

The developing devices 1a, 1b, 1c and 1d are filled with a predetermined amount of cyan, magenta, yellow and black toners as a developer by a supply device (not shown). The developing devices 1a, 1b, 1c and 1d develop the latent images on the photosensitive drums 3a, 3b, 3c and 3d, respectively, and visualize them as cyan toner images, magenta toner images, yellow toner images and black toner images.

The recording material P is accommodated in the recording material cassette 10, and from there, a plurality of conveying rollers and registration rollers 12 are provided.
Is fed onto the conveyor belt 130 via the
When the sheet is conveyed by 0, it is sequentially sent to the transfer section facing the photosensitive drums 3a, 3b, 3c and 3d.

The conveyor belt 130 is made of a dielectric resin sheet such as a polyethylene terephthalate resin sheet (PET sheet), a polyvinylidene fluoride resin sheet, or a polyurethane resin sheet, and both ends thereof are superposed and joined to each other. , Either endless or seamless (seamless) belts are used.

In the case of a belt having no seam, it is not only difficult to manufacture it so as to have uniform physical properties, but also in terms of stability of the belt circumference and manufacturing time.
It is not suitable for mass production in terms of cost. On the other hand, in the case of a belt having a seam, the unevenness of the seam portion and the change of the physical properties such as the resistance value are unavoidable, and the image is disturbed when the image is formed on the seam. Therefore, in order to obtain a high quality image, the circumference of the conveyor belt 130 is set to the total length of the length of the recording material and the length of the gap between the recording material and the next recording material (length between papers). In addition to making it an integral multiple, it is general to provide a means for detecting the seam position so as not to form an image on the seam.

As a means for detecting the seam position, a reflective optical sensor is used when the conveyor belt 130 is opaque, and a seam position is detected by providing a detection mark having different light reflection characteristics at the seam portion. When the transport belt 130 is transparent, the transmissive optical sensor is used to directly detect the seam position, or the displacement sensor is used to mechanically detect the seam position by means of the notches or protrusions provided at the seam.

When the conveyor belt 130 is rotated by a plurality of supporting rollers or the like, generally, the conveyor belt 130 is in a width direction (thrust direction, that is, the same direction as the axial direction of the supporting rollers) perpendicular to the rotating direction. 1) one side of the belt is deviated to one side, which causes damage such as damage to the belt end portion. The deviation of the transport belt 130 causes a difference in the tension of the transport belt 130 in the thrust direction due to a difference in the circumferential length of the transport belt 130 in the thrust direction, a difference in the circumferential length of the support rollers, a distortion of the belt support unit, and the like. This is because the belt tension difference in the thrust direction causes stress in any of the thrust directions.

Therefore, a deviation prevention mechanism on the belt side, for example, a rib or an end guide hole is installed on the back surface of the conveyor belt 130, or a deviation prevention mechanism on the belt rotation mechanism side, for example, a support roller for the conveyor belt 130. The control mechanism and the like are installed. However, in any case, it is quite difficult to rotate the conveyor belt 130 so that the conveyor belt 130 is not displaced in the thrust direction. Therefore, the conveyor belt 130 is rotated while repeatedly shifting in both thrust directions with a certain width.
The shift width in both directions in the thrust direction is called the swing width, and the mechanism for swinging by this swing width is called the swing mechanism.

An example in which this swing mechanism is installed on the conveyor belt 130 will be described with reference to FIG. FIG. 8 shows an example in which the swinging mechanism is installed on the belt rotating mechanism side, and particularly, the conveyor belt 130.
This is often done when a thin-walled belt that is advantageous for improving the dielectric constant is used.

As shown in FIG. 7, the conveyor belt 130
Is suspended around a drive roller 13 on the downstream side in the transport direction and a pair of support rollers 14 and 15 on the upstream side. The drive roller 13 is a roller having a rubber surface layer, and is rotationally driven to rotate the conveyor belt 130. Both ends of the support roller 14 are fixed using springs or the like, and the tension of the rotating conveyor belt 130 is kept constant.
The support roller 15 is a swing roller that causes the transport belt 130 to swing.

FIG. 8 shows the swing roller 15 and the conveyor belt 1.
FIG. 13 is a plan view of 30 viewed from the support roller 14 side, showing the movement of the swing roller 15 when swinging. The conveyor belt 130 is located below the swing roller 15 and moves in the upward C direction in the figure. Detection sensors A ′ and B ′ that detect when both end portions of the conveyor belt 130 are deviated to the α side and the β side, respectively, are provided near the outer ends α and β of the conveyor belt 130 in the width direction. .
When the detection sensor A ′ detects the deviation of the conveyor belt 130 toward the α side, the swing roller 15 moves in the direction A in the upper part of the drawing, thereby moving the conveyor belt 130 in the leftward direction a. Similarly, the detection sensor B ′ is the conveyor belt 1
When the deviation of 30 toward the β side is detected, the swing roller 15 moves in the downward B direction, thereby moving the conveyor belt 130 in the rightward b direction.

As described above, the conveyor belt 130 has α
-Rotate while swinging between β. The swing width described above is
From the distance between α and β, which is the full width of the swing, the conveyor belt 130
Subtract the width of and divide by 2 to obtain the one-sided amount.

Now, when it is confirmed that the conveyor belt 130 rotates and is in a predetermined position, the registration roller 1
The recording material P is sent out from 2 to the conveyor belt 130, and the recording material P is conveyed toward the transfer portion of the first image forming portion Pa. At the same time, the image writing signal is turned on, and the image is formed on the photosensitive drum 3a of the first image forming portion Pa at a certain timing based on the signal. Then, the brush transfer charger 24a applies an electric field or an electric charge at a transfer portion below the photosensitive drum 3a, so that the toner image of the first color formed on the photosensitive drum 3a is transferred onto the recording material P. . By this transfer, the recording material P is firmly held on the conveyor belt 130 by the electrostatic attraction force, and is conveyed to the second image forming portion Pb and thereafter.

Similarly, image formation and transfer are performed in the second image forming portion Pb to the fourth image forming portion Pd. Next, the recording material P on which the four color toner images have been transferred is neutralized by the separation charging device 32 at the downstream side in the transport direction of the transport belt 130 and the electrostatic force is attenuated.
Leave from there at the end of 0. The released recording material P is
It is transported to the fixing device 9 by the transport unit 62.

The fixing device 9 includes a fixing roller 51, a pressure roller 52, heat-resistant cleaning members 54 and 55 for cleaning each of them, roller heaters 56 and 57 installed in the rollers 51 and 52, and fixing. The roller 51 comprises a coating roller 50 for coating a release agent oil such as dimethyl silicone oil, a reservoir 53 for the oil, and a thermistor 58 for detecting the temperature of the surface of the pressure roller 52 and controlling the fixing temperature. . The recording material P onto which the four color toner images have been transferred is mixed to fix the toner images on the recording material P to form a full-color copy image.

By the way, the color toner is required to have good melting property and color mixing property when heated by the fixing device 9. If the melting and color mixing properties are poor, the air gap between the toner particles will increase, and the toner will lose its original color tone due to the scattering of light at the interface with the air. This is because the above toner is hidden by the toner in the upper layer and the color reproducibility is deteriorated. As a toner satisfying these melting properties and color mixing properties, a so-called sharp melt toner having a low softening point and a low melt viscosity is used. By using such a sharp melt toner, color reproducibility can be enhanced and a color copy faithful to the original can be obtained.

However, the sharp melt type toner has a drawback that it tends to be offset to the fixing roller of the fixing device because of its high affinity. In the fixing device, pressure is applied in addition to heating, and the toner having a high affinity has a tendency to be transferred and adhered to the fixing roller by the heating and pressing. When toner adheres to the fixing roller, this toner adheres to the next recording material or solidifies on the fixing roller.
Either of them causes a defective image.

The release agent oil such as dimethyl silicone is
It is used to prevent the occurrence of these image defects, and a releasing agent oil is applied onto the fixing roller before fixing the toner image on the recording material. As a result, when the recording material onto which the toner image has been transferred is heated and pressed, the fixing roller does not come into direct contact with the toner image via the release agent oil, so the toner adheres to the fixing roller side. Can be effectively prevented.

Photosensitive drums 3a, 3b, 3 which have been transferred
The toners c and 3d are cleaned and removed by the cleaners 4a, 4b, 4c and 4d, respectively, and the residual toner after transfer is prepared for the subsequent latent image formation. Toner and other foreign matter remaining on the conveyor belt 130 are
A cleaning web (nonwoven fabric) 19 is brought into contact with the surface of the conveyor belt 130 and wiped off.

[0028]

The cleaning web 19 is wound around one web roller 18 of a pair of rollers disposed below the downstream end of the conveyor belt 130, and the other web 17 is wound around the web roller 18. It is designed to be rolled up. A pressing roller 22 is disposed between the rollers 17 and 18, and the cleaning roller 19 is provided by the pressing roller 22.
Is pressed against the surface of the conveyor belt 130. Pressing roller 22
The pressing of the cleaning web 19 against the conveyor belt 130 by the above is backed up by the facing roller 21 arranged on the back side (inner side) of the conveyor belt 130.

As the fibers of the cleaning web 19,
Fibers such as polypropylene, rayon, acrylic, nylon, polyester and vinylon, and mixtures of these fibers are preferred.

The pressing roller 22 and the counter roller 21 also serve as a charge eliminating means for reducing the charge-up of the conveying belt 130, and apply a DC bias having a polarity opposite to the electric field (DC electric field) of the transfer chargers 24a to 24d. It is configured such that it can be applied as a static elimination bias. The static elimination bias is applied to the pressing roller 22 and / or the counter roller at the same time as the rotation of the conveyor belt 130 is started so that the static electricity is constantly removed by the pressing roller 22 and the counter roller 21 while the conveyor belt 130 is rotating. A DC bias is applied to the roller 21.

When performing double-sided image formation on the recording material P, after the transfer of the first side is completed and the recording material P has passed through the fixing device 9, the recording material P is not conveyed to the discharge tray 63, but a flapper (reversing member) or the like is used. The sheet is conveyed to a conveying path dedicated to double-sided image formation.
Then, the recording material P is turned upside down and the transport belt 130 is retransmitted, and the image formation is performed again on the second surface opposite to the first surface (first surface) where the image formation is completed. At this time, the release agent oil adhering to the first surface of the recording material P, especially to the toner image thereof, adheres to the surface of the conveyor belt 130, and further adheres from the conveyor belt 130 to the photosensitive drums 3a to 3d.

Cleaners 4a-4 of the photosensitive drums 3a-3d
The purpose of d is to remove the toner on the photosensitive drums 3a to 3d, and the release agent oil attached cannot be removed sufficiently. For this reason, a problem peculiar to double-sided color copying occurs that an image is defective due to the release agent oil contamination of the photosensitive drum.
Therefore, conventionally, the cleaning web 19, which is a cleaning member of the conveyor belt 130, is configured to clean not only the residual toner on the surface of the conveyor belt 130 but also the released oil adhering to the surface.

However, since the conveyor belt 130 is displaced in the thrust direction due to its rotation, the conveyor belt 1
A portion where the cleaning web 19 does not come into contact with both end portions of the portion 30 cannot remove the adhered toner, the release agent oil, and other foreign matter at that portion. Therefore, not only transfer failure due to cleaning failure but also image failure due to release agent oil contamination of the photosensitive drum occurs.

Further, since the conveyor belt 130 is displaced in the thrust direction, when the electricity is removed from the conveyor belt 130 by the pressure roller 22 and the counter roller 21, the pressure roller is interposed between the conveyor belt 130 and the cleaning web 19 and the other area. There is a difference in the impedance between 22 and the counter roller 21, which causes a difference in the static elimination effect. As a result, an image defect occurs due to nonuniform charge removal of the conveyor belt 130.

An object of the present invention is to record a recording material carrying member such as a conveyor belt when a sheet-shaped cleaning member is brought into contact with the recording material carrying member for cleaning, even if the recording material carrying member is displaced in the thrust direction due to rotation. It is possible to obtain a high-quality image free from the transfer failure due to the adhered matter and the image defect due to the contamination of the image carrier by removing the toner, the release agent oil, and other foreign matter adhered by properly cleaning the material supporting member. An image forming apparatus is provided.

Another object of the present invention is to further provide a pressing member and / or
Alternatively, when a discharging bias is applied to the support member that backs up the pressing force to further discharge the recording material carrying member, even if the recording material carrying member is displaced in the thrust direction due to rotation, the recording material carrying member It is an object of the present invention to provide an image forming apparatus capable of obtaining a high-quality image free from transfer defects due to non-uniform charge removal of a recording material carrying member by setting a charge removal region to favorably charge the charge removal region.

[0037]

The above object can be achieved by an image forming apparatus according to the present invention. In summary, the present invention is directed to an image carrier on which a latent image is formed, a recording material carrying member which is provided adjacent to the image carrier and which carries and rotates a recording material, and a latent image on the image carrier. A transfer unit for transferring the toner image obtained by developing the image onto the recording material on the recording material carrying member is provided, and recording is performed during a series of image forming operations from the formation of the latent image to the transfer of the toner image. An image forming apparatus having a cleaning unit including a sheet-like cleaning member that comes into contact with the surface of a material-carrying member to be cleaned and a pressing member that presses the cleaning member to come into contact with the surface of the recording-material carrying member. An image forming apparatus wherein the cleaning member and the pressing member have a thrust direction width that is greater than the swing width of the recording material carrying member that swings in a direction perpendicular to the direction of rotation of the recording material carrying member. Is.

According to another aspect of the present invention, the pressing member is made of a conductive member, and the pressing is applied to the opposite side of the contact portion of the sheet-like cleaning member with the recording material carrying member. Equipped with a conductive support member to back up,
To the pressing member and / or the supporting member, an AC neutralization bias or a DC neutralization bias having a reverse polarity to the transfer bias applied to the transfer means is applied to neutralize the recording material carrying member. The static elimination width in the thrust direction of the recording material carrying member by the pressing member and the supporting member is equal to or less than the thrust direction width excluding the swing width of the recording material carrying member.

A winding means for winding the sheet-like cleaning member may be further provided so as to move in a direction opposite to the rotating direction of the recording material carrying member. In addition to the cleaning means, cleaning assisting means for contacting the recording material carrying member to clean the surface of the carrying member may be provided. The cleaning assisting means comprises a plate-shaped or brush-shaped cleaning member, and the cleaning member is brought into contact with the recording material carrying member between the pressing member and the winding means. Furthermore, the cleaning assisting means is composed of a portion of the sheet-like cleaning member located upstream and / or downstream of the pressing member, and the back surface side of the cleaning member is brought into contact with the recording material carrying member.

[0040]

【Example】

Embodiment 1 FIG. 1 is a sectional view showing the structure of an image forming apparatus in an embodiment of the present invention. In this embodiment, as shown in FIG.
The cleaning web 1 in which the cleaning means for the conveyor belt 130 of the image forming apparatus is pressed against the surface of the conveyor belt 130.
9 and the pressing roller 22 are different from the conventional image forming apparatus shown in FIG. 7, and other configurations are basically the same. In FIG. 1, the same reference numerals as those shown in FIG. 7 denote the same members.

In this embodiment, the width of the cleaning web 19 and its pressing roller 22 in the thrust direction is defined according to the width of the conveyor belt 130 in the thrust direction and the swing width of the conveyor belt 130 in the thrust direction. As a result, excellent cleaning of the conveyor belt 130 is realized.

In this embodiment, the conveyor belt 130, which is an endless recording material carrying member, is formed to have a thickness of 150 μm and a width of 334 mm in the thrust direction which is perpendicular to the rotating direction, and rotates at a speed of 100 mm / sec. Be moved. Conveyor belt 1
The conveyance of the recording material P by 30 is, of course, the first image forming unit P.
The direction is from a to the fourth image forming portion Pd.

FIG. 2 is an explanatory view showing a method for defining the width in the thrust direction of the cleaning web and the pressing roller according to this embodiment. As shown in FIG. 2, with respect to the conveyor belt 130 having a width of 334 mm, the swing width of the conveyor belt 130 on both the α side and the β side is
It was 8 mm. The width in which the conveyor belt 130 that swings by rotation can exist is 350 mm.

The cleaning member 19 is the conveyor belt 13
Even if 0 swings, it is important for maintaining the cleaning performance that it is in contact with the entire portion of the width of the conveyor belt 130 in the thrust direction. Therefore cleaning web 1
The width of 9 needs to be at least 350 mm, which is the same as the width of the conveyor belt 130 (belt existence width).

However, due to the rotation and swing of the conveyor belt 130, the cleaning web 19 itself is also displaced in the thrust direction, and an accident such as the cleaning web 19 protruding from the pressing roller 22 may occur. Therefore, in the present embodiment, in order to prevent this and stably maintain the cleaning performance, the width of the cleaning web 19 is set to 354 mm by allowing a margin of 4 mm for 350 mm.

The pressing roller 22 is wider than that,
It is necessary to uniformly press the cleaning web 19, and in this embodiment, the pressing roller 22 has a thrust direction width of 360 mm.

As described above, in this embodiment, the width of the cleaning web 19 for cleaning the rotating conveyor belt 130 is made wider than the width where the conveyor belt 130 can exist due to the swinging accompanying the rotation, and the cleaning is performed. Since the width of the pressing roller 22 that presses the web 19 against the conveyor belt 130 is made wider than the width of the cleaning web 19, the cleaning performance of the cleaning web 19 with respect to the conveyor belt 130 can be stably maintained, and the conveyor belt 130 can be maintained on both sides thereof. Can be satisfactorily cleaned up to the end. Therefore, not only the toner adhered on the conveyor belt 130 but also the release agent oil at the time of double-sided image formation can be removed well, and the high quality image in which the transfer failure due to these adhered matters or the image failure due to the contamination of the photosensitive drum is prevented. Can be obtained.

Embodiment 2 This embodiment shows a case where it is applied to the image forming apparatus of FIG. In this embodiment, when cleaning the transport belt 130, the pressure on the transport belt 130 was removed by the pressing roller 22 and the counter roller 21. In the present embodiment, by stipulating the relationship among the image width (recording material width) at that time, the width of the transport belt 130 in the thrust direction, the static elimination width, and the width of the pressing roller 22 and the like, good static elimination of the transport belt 130 is realized. did.

FIG. 3 is an explanatory view of a method of defining the image width and the like at the time of removing charge during cleaning of the conveyor belt. In the apparatus of this embodiment, when the discharging belt 22 and / or the counter roller 21 made of a conductive material is applied with a discharging bias to remove the discharging of the conveying belt 130, the conveying belt 130 and the cleaning web 19 are displaced in the thrust direction. Even if there is no difference in the impedance between the pressing roller 22 and the counter roller 21, if the thrust direction area of the pressing roller 22 and the counter roller 21 is the static elimination width (static elimination area), the corresponding conveyor belt 130 It is possible to uniformly remove the electric charge in the thrust direction area.

Also in this embodiment, as in the first embodiment, the width of the conveyor belt 130 is 334 mm, the swing width thereof is on the α side,
The width on the β side is 8 mm, and the possible width of the conveyor belt 130 is 33 mm.
4 mm and the width of the cleaning web 19 is 354 m
m, and the width of the pressing roller 22 is 360 mm.

Therefore, the pressing roller 22 and the counter roller 21
On the other hand, the thrust direction region where the conveyor belt 130 always exists defines the upper limit of the static elimination width, and the upper limit of the static elimination width is from the width 334 mm of the conveyor belt 130 to the swing width 8 mm × 2 on the α side and the β side. It is 318 mm drawn. On the other hand, the apparatus of this embodiment is compatible with A3 size paper at the maximum, and the maximum thrust direction width of the recording material used (also the maximum image width) is about 300 mm, which is the short side of the A3 size. Also, a large static elimination width is required. Therefore, the lower limit of the static elimination width by the pressing roller 22 and the opposing roller 21 is about 300 mm. From the above, in the present embodiment, the intermediate width of 310 mm was set as the static elimination width by the pressing roller 22 and the counter roller 21.

Therefore, in order to make the static elimination width by the pressing roller 22 and the counter roller 21 having a width of 360 mm 310 mm,
The width of the opposing roller 21 is 310 mm. The opposing roller 21 may be made of a conductive material in a range of 310 mm with respect to the center of the thrust width, and may be made of an insulating material in a portion longer than that. The same applies to the pressing roller 22.

In the present embodiment, as described above, the static elimination width by the pressing roller 22 and the counter roller 21 is defined.
While maintaining the cleaning performance of the cleaning belt 19 of the conveyor belt 130, at the same time, the conveyor belt 130 is cleaned.
The static elimination area of can be uniformly eliminated. By the way, the pressing roller 2
-5 kV as a direct current bias having a polarity opposite to that of the transfer bias applied to the transfer charger to both the 2 and the opposite roller 21.
However, it was possible to obtain a high-quality image without transfer defects due to uneven charge removal by uniformly removing the charge removal area of the transport belt 130.

In the above description, the discharging bias of -5 kV is applied to both the pressing roller 22 and the facing roller 21, but the same effect can be obtained by applying -5 kV to only one of them and grounding the other. was gotten. Further, the static elimination bias was constant voltage control, but the same effect was obtained by constant current control. Further favorable results were obtained by superimposing alternating current on direct current. Although the facing roller 21 was used as the backup member and the static eliminator, it is not limited to the roller shape and may be a plate shape or a brush shape in which conductive fibers are implanted.

Embodiment 3 In this embodiment, in addition to the cleaning web 19, the cleaning belt 19 is provided with other cleaning assisting means. FIG. 4 is a schematic cross-sectional view showing the vicinity of the cleaning unit in this embodiment. 4, the same reference numerals as those shown in FIG. 7 indicate the same members.

Cleaning Web 1 for Conveyor Belt 130
In No. 9, it is not necessary to continuously update a new surface, and a use form in which a fixed amount is wound for every fixed number of image formations may be used. In this embodiment, the number of images formed is 100 and the cleaning web 19
Was wound on the winding roller 17 by 5 mm and renewed.

In this embodiment, a cleaning blade 23 made of polyurethane rubber is provided as a cleaning assisting means. The cleaning blade 23 has a JIS rubber height of about 65 degrees. Cleaning blade 2
No. 3 was brought into contact with the surface of the conveyor belt 130 between the contact portion of the cleaning web 19 with the conveyor belt 130 and the winding roller 17. The contact angle of the cleaning blade 23 with the conveyor belt 130 is about 20 degrees, and the intrusion amount is 1.5 to
It was set to 2.0 mm.

This cleaning assisting means, that is, the cleaning blade 23, conveys the recording material especially when the cleaning web 19 intended for wiping off the scattered toner, paper dust and the like adhering to the conveyor belt 130 cannot be sufficiently cleaned. When an image is formed on the conveyor belt 130 due to a defect, or when there is more toner than usual due to stabilization control of the recorded image (for example, in order to maintain registration or density uniformity, feedback control thereof is performed). It is effective for cleaning the conveyor belt 130 when it can be predicted in advance that the patch image to be used is formed on the conveyor belt 130.

According to the present embodiment, the cleaning blade 23 mainly removes foreign matter such as toner and dust adhering to the surface of the conveyor belt 130, and the next cleaning with the cleaning web 19 not only separates the toner and foreign matter. Mold oil is removed well. For this reason, the cleaning performance of the conveyor belt 130 was improved and good results were obtained. The toner or the like attached to the cleaning web 19 is collected by the winding roller 17 together with the cleaning web 19.

Although the cleaning blade 23 is used as the cleaning assisting means in the above, the same result can be obtained by using a fur brush instead.

Further, as shown in FIG. 5, in addition to the contact of the cleaning web 19 with the conveyor belt 130 by the pressing roller 22, the back surface of the cleaning web 19 opposite to the contact surface is either of the rollers 17 or 18. It is possible to contact the conveyor belt 130 by pressing the rollers at those positions, which is more effective. This is also included in the scope of the present invention. In the case shown in FIG. 6, the back surface of the cleaning web 19 is placed on both sides of the rollers 17 and 18 and the conveyance belt 130.
The cleaning blade 23 to the roller 17
And the pressing roller 22 are in contact with the conveyor belt 130. Even better results are obtained.

[0062]

As described above, according to the present invention, when the sheet-like cleaning member is pressed by the pressing member to come into contact with the surface of the endless recording material carrying member to clean the recording material carrying member, Since the width in the thrust direction of the cleaning member and the pressing member is defined to be larger than the swing width in the thrust direction due to the rotation of the recording material carrying member, even if the recording material carrying member is displaced in the thrust direction due to the rotation, Properly clean the recording material support member to remove adhered toner, release agent oil, and other foreign matter, and obtain high-quality images free from transfer defects due to adhered substances and image defects due to contamination of the image carrier. You can

When a discharging bias is applied to the pressing member and / or a supporting member that backs up the pressing to further discharge the recording material carrying member, the pressing member and the supporting member remove the charge in the thrust direction of the recording material carrying member. By defining the width to be equal to or less than the thrust direction width excluding the swing width of the recording material carrying member, even if the recording material carrying member is displaced in the thrust direction due to the rotation, the static elimination area of the recording material carrying member is set. By setting, it is possible to satisfactorily eliminate the charge in the charge removal area, and to obtain a high-quality image without transfer defects due to uneven charge removal of the recording material carrying member.

[Brief description of drawings]

FIG. 1 is a sectional view showing a configuration of an image forming apparatus according to an embodiment of the present invention.

FIG. 2 is an explanatory diagram showing a method of defining a cleaning web of a conveyor belt and a width of a pressing roller in a thrust direction in the image forming apparatus of FIG.

FIG. 3 is an explanatory diagram showing a method of defining a width in a thrust direction of a charge eliminating region of a conveyor belt by a pressing roller and a counter roller according to another embodiment of the present invention.

FIG. 4 is a schematic cross-sectional view showing the vicinity of a cleaning portion of a conveyor belt according to still another embodiment of the present invention.

FIG. 5 is a schematic cross-sectional view showing another example of a method for cleaning a conveyor belt according to the present invention.

FIG. 6 is a schematic cross-sectional view showing another example of the method for cleaning the conveyor belt according to the present invention.

FIG. 7 is a sectional view showing a configuration of a conventional image forming apparatus.

8 is an explanatory diagram showing a swing mechanism including swing rollers provided on a conveyor belt of the image forming apparatus in FIG.

[Explanation of symbols]

 3a to 3d Photosensitive drum 4a to 4d Cleaner 15 Swing roller 17 Winding roller 18 Web roller 19 Cleaning web 21 Opposing roller 22 Pressing roller 23 Cleaning blade 50 Fixing device 130 Conveyor belt

Front page continuation (72) Inventor Gaku Fujita 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc.

Claims (6)

[Claims] 1. An image bearing member on which a latent image is formed, a recording material bearing member which is provided adjacent to the image bearing member and which carries and rotates a recording material, and a latent image on the image bearing member. A transfer unit that transfers the toner image obtained by development onto the recording material on the recording material holding member is provided, and the recording material is held during a series of image forming operations from the formation of the latent image to the transfer of the toner image. An image forming apparatus comprising a sheet-like cleaning member that comes into contact with the surface of a member to be cleaned, and a pressing member that presses the cleaning member to come into contact with the surface of a recording material carrying member. The image forming apparatus is characterized in that the member and the pressing member have a thrust direction width that is larger than the swing width of the recording material carrying member that swings in a direction perpendicular to the rotating direction of the recording material carrying member. 2. The pressing member is made of a conductive member, and a conductive support member for backing up the pressing is provided on the opposite side of the contact portion of the sheet-like cleaning member against the recording material carrying member by the pressing of the pressing member. The pressing member and / or the supporting member are provided with a neutralizing bias of alternating current or a neutralizing bias of direct current having a polarity opposite to that of the transfer bias applied to the transfer means to neutralize the recording material carrying member. The image forming apparatus according to claim 1, wherein the width of static elimination in the thrust direction of the recording material carrying member by the pressing member and the supporting member is less than the width in the thrust direction excluding the swing width of the recording material carrying member. 3. The image forming apparatus according to claim 1, further comprising a winding unit that winds the sheet-like cleaning member so as to move in a direction opposite to a rotating direction of the recording material carrying member. 4. The image forming apparatus according to claim 1, further comprising, in addition to the cleaning unit, a cleaning assist unit that contacts the recording material carrying member to clean the surface of the carrying member. 5. The cleaning assisting means comprises a plate-like or brush-like cleaning member, and the cleaning member is brought into contact with the recording material carrying member between the pressing member and the winding means. Image forming apparatus. 6. The cleaning assisting means comprises a portion of the sheet-like cleaning member located on the upstream side and / or the downstream side of the pressing member, and the back surface side of the cleaning member contacts the recording material carrying member. 4. The image forming apparatus of 4.