JP2000231280A - Image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make obtainable a sufficient polishing effect of the surface of an intermediate transfer body without bringing about an enlargement of the device or rising of the cost by feeding an abrasive to the surface of the intermediate transfer body and polishing the surface of the intermediate transfer body at the abutted part of a cleaning means and the intermediate transfer body at the time of cleaning. SOLUTION: In the image forming device, the abrasive 74 is fed to the surface of the intermediate transfer belt 21 by an abrasive feeding device 70 when the cleaning device 50 is working outside of an image forming process. The abrasive 74 fed to the surface of the intermediate transfer belt 21 is carried to the cleaning device 50 with the intermediate transfer belt 21. The abrasive 74 fed to the surface of the intermediate transfer belt 21 is attached to an edge part of a cleaning blade 51 in the abutted part of the cleaning blade 51 and the intermediate transfer belt 21. Then, the surface of the intermediate transfer belt 21 is polished by the abrasive 74 and the surface is made smooth as well as having discharge product eliminated.

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 using an electrophotographic process, such as an electrophotographic copying machine, a facsimile, a printer, etc., which intermediately transfers toner images of different colors sequentially formed by image forming means. The present invention relates to an image forming apparatus for forming an image by temporarily transferring a toner image multiplexed onto the intermediate transfer body and then secondary-transferring the toner image multiplexed onto the transfer member at once, and particularly, The present invention relates to a technique for removing a discharge product attached to a transfer body.

[0002]

2. Description of the Related Art Conventionally, as an image forming apparatus such as a copying machine or a printer utilizing the above-mentioned electrophotographic process, there is, for example, the following one. As shown in FIG. 9, the image forming apparatus such as a copying machine or a printer uniformly charges the surface of the photosensitive drum 100 to a predetermined potential by a scorotron 101 for primary charging. ROS (Ra)
An electrostatic latent image is formed by performing a scanning exposure using a “Ster Output Scanner” 102. Then, the image forming apparatus converts the electrostatic latent image formed on the surface of the photosensitive drum 100 into developing units 103Y, 103M, 103C,
By developing with 3BK, the photosensitive drum 10
The toner images of yellow, magenta, cyan, black, etc. are sequentially formed on 0. Thereafter, the image forming apparatus performs a primary transfer of the toner images of yellow, magenta, cyan, black, and the like sequentially formed on the photosensitive drum 100 on the intermediate transfer belt 104 in a state of being superimposed on each other. The toner image of a predetermined number of colors, which is multiplexed and transferred onto the belt 104, is transferred to the transfer sheet 1 by the pressing force between the backup roll 105 and the secondary transfer roll 106 and the electrostatic force.
After the image is collectively transferred onto the transfer sheet 107, an unfixed toner image of a predetermined number of colors is fixed on the transfer sheet 107 by the fixing device 108, thereby forming a color or monochrome image.

Further, the above-mentioned image forming apparatus such as a copying machine or a printer is provided with a transfer paper 10 for an unfixed toner image of a predetermined number of colors.
7 after the completion of the secondary transfer onto the intermediate transfer belt 104.
The toner, paper powder, and the like adhering to the upper surface are removed by a cleaning device 110 having a cleaning blade 109 made of an elastic material such as polyurethane, so as to prepare for the next image forming step. The cleaning blade 109 of the cleaning device 110 is used.
For example, among a plurality of rolls rotatably supporting the intermediate transfer belt 104, a plurality of rolls are disposed in the vicinity of a driving roll 111 for driving the intermediate transfer belt 104 so as to be in pressure contact with the surface of the intermediate transfer belt 104. ing.

In such an image forming apparatus, when a color image is formed, as shown in FIG.
It is necessary to transfer yellow, magenta, cyan, black, and other toner images sequentially formed on the photosensitive drum 100 onto the intermediate transfer belt 104 in a state where they are superimposed on each other. Therefore, the cleaning blade 109 of the cleaning device 110 that cleans the surface of the intermediate transfer belt 104 is normally retracted to a position retracted (separated) from the intermediate transfer belt 104 as shown in FIG. After the final toner image is secondarily transferred onto the transfer sheet 107, as shown in FIG. 10B, contact with the surface of the intermediate transfer belt 104 is started, and as shown in FIG. The surface of the intermediate transfer belt 104 is configured to stop in an advanced state (contact) with a predetermined pressure contact force, and to remove attached matter such as toner remaining on the surface of the intermediate transfer belt 104. Then, in the image forming apparatus, when forming a color image or the like continuously,
The cleaning blade 109 that has completed the step of cleaning the surface of the intermediate transfer belt 104 retracts (separates) from the intermediate transfer belt 104 while the intermediate transfer belt 104 is moving.

[0005]

However, the above-mentioned prior art has the following problems. That is, in the case of the conventional image forming apparatus, the transfer paper 10
7, color and black-and-white images can be formed on thick paper and OHP sheets in addition to plain paper. The backup roll 1 is used to transfer the toner image transferred on the intermediate transfer belt 104 onto a transfer member 107 made of thick paper, an OHP sheet, or the like.
A high voltage (about 2.7 kV), which is much higher than usual, is applied between the secondary transfer roll 05 and the secondary transfer roll 106 to increase the transfer electric field. Therefore, in the above-described conventional image forming apparatus, when the toner image is transferred onto the transfer member 107 made of a thick paper, an OHP sheet, or the like, the transfer member 107 is connected to the SEF (Short Edge Feed:
When the paper is conveyed by short feed, a portion where the transfer member 107 is not interposed inevitably occurs in a region where the backup roll 105 and the secondary transfer roll 106 are pressed against each other via the intermediate transfer belt 104. In a region where the backup roll 105 and the secondary transfer roll 106 are in direct pressure contact with each other via the intermediate transfer belt 104, a discharge occurs due to a minute gap between the secondary transfer roll 106 and the intermediate transfer belt 104. A discharge product adheres to the surface of the intermediate transfer belt 104 or the surface of the intermediate transfer belt 104 is damaged by a discharge phenomenon, so that a friction coefficient increases.

Under these circumstances, in the case of the conventional image forming apparatus, as shown in FIG. 10, a cleaning blade 109 for cleaning the surface of the intermediate transfer belt 104 is used.
However, it is necessary to perform advance (contact) and retract (separation) operations while the intermediate transfer belt 104 is moving. At that time, the cleaning blade 109 is
As shown in FIG. 11, when the edge 109a starts to contact the surface of the intermediate transfer belt 104, a frictional force Fm determined by the kinetic friction coefficient between the blade edge 109a and the surface of the intermediate transfer belt 104 is generated. I do.

At this time, if a discharge product adheres to the surface of the intermediate transfer belt 104 or the surface of the intermediate transfer belt 104 is damaged by a discharge phenomenon and the friction coefficient increases, the blade edge 109a and the The frictional force Fm generated between the intermediate transfer belt 104 and the surface of the intermediate transfer belt 104 is significantly larger than that in a case where no discharge product is attached to the surface of the intermediate transfer belt 104 and no damage is caused by the discharge. .

Therefore, the cleaning blade 10
When the blade edge 109a of No. 9 is further pressed against the surface of the intermediate transfer belt 104, the frictional force Fm generated between the blade edge 109a and the surface of the intermediate transfer belt 104 is further increased with the increase of the pressing force. As shown, the frictional force Fm causes the phenomenon that the blade edge 109a is pulled along the moving direction of the intermediate transfer belt 104. The tip of the blade 109 including the blade edge 109a is connected to the cleaning blade 10
9 is easily deformed as compared with the intermediate portion, and when pulled along the moving direction of the intermediate transfer belt 104 as described above, the blade edge 109a and its peripheral portion are chipped or inverted ( There is a problem that damage such as turning up occurs.

In addition, the cleaning blade 109
Is the blade edge 109a as shown in FIG.
Further presses against the surface of the intermediate transfer belt 104, the frictional force Fm generated between the blade edge 109a and the surface of the intermediate transfer belt 104 increases with the increase of the pressing force, and the amount of deformation of the blade edge 109a gradually increases. Become. Then, since the cleaning blade 109 is made of an elastic material such as polyurethane, the blade edge 10
When the portion 9a and its surrounding portion are greatly deformed, a repulsive elastic force Fp based on the repulsive elasticity of the elastic body constituting the blade acts as an internal stress inside the blade edge 109a according to the amount of the deformation. When the repulsive elastic force Fp generated inside the blade edge 109a and its surroundings exceeds the frictional force Fm, the blade edge 109a
, As shown in FIG. 11, is instantaneously returned to the original shape by the repulsive elastic force Fp.

As described above, the cleaning blade 1
12, a tensile force Fm along the moving direction of the intermediate transfer belt 104 is applied to the blade edge 109a from the start of contact with the surface of the intermediate transfer belt 104 until a predetermined pressure-contact state is reached, as shown in FIG. And the blade edge 109a is deformed in the direction of movement of the intermediate transfer belt 104, and when it is deformed to some extent, a so-called "stick-slip" phenomenon of returning to the original shape is repeated. Therefore, the cleaning blade 109 is
As shown in the figure, from the start of contact with the surface of the intermediate transfer belt 104 to the time when a predetermined pressure contact state is reached, the contact with the surface of the intermediate transfer belt 104 in a very unstable state occurs, and the blade edge 109a and its Stress and strain repeatedly act on the surrounding part. As a result, in the cleaning blade 109, the blade edge 109a is further damaged by the repetitive stress, and the blade edge 109a is damaged, such as chipping or reversal. There is a problem that image quality defects occur due to the occurrence of the image. FIG. 13 is a schematic diagram showing a state in which damage such as chipping or reversal has occurred in the blade edge 109a, taken by an electron microscope.

In order to reduce the friction coefficient of the surface of the intermediate transfer belt 104,
The surface associated with the intermediate transfer belt 104 can be polished. Examples of techniques related to the surface polishing of the intermediate transfer belt 104 and the like include, for example, JP-A-7-175346 and JP-A-8-8-8.
There is one disclosed in, for example, Japanese Patent No. 2949.

An image forming apparatus according to Japanese Patent Application Laid-Open No. 7-175346 discloses a recording material carrier for carrying and conveying a recording material, and an image forming means for forming an image on the recording material carried on the recording material carrier. In the image forming apparatus having
A polishing means containing an abrasive is provided on the surface, and the recording material carrier is polished by the polishing means.

Further, the toner composition for electrostatic charge development according to the above-mentioned Japanese Patent Application Laid-Open No. 8-82949 is configured such that fluorine-containing cerium oxide fine particles are added to toner particles.

However, among the techniques according to the above proposal, in the case of the former image forming apparatus disclosed in Japanese Patent Laid-Open No. 7-175346, not the intermediate transfer member but the recording material carrier is polished by the polishing means. However, when the polishing means for directly polishing the surface of the recording material carrier is provided as described above, a collecting mechanism for collecting the shavings polished by the polishing means is required. However, there is a problem that the size is increased and the cost is increased.

On the other hand, among the techniques according to the above proposals, in the latter case of the toner composition for electrostatic charge development according to JP-A-8-82949, fluorine-containing cerium oxide fine particles are added to the toner particles as an abrasive. However, since the abrasive composed of the fine particles of cerium oxide containing fluorine is a fine powder, it is difficult to be transferred from the surface of the photosensitive drum to the intermediate transfer body, and as a result, the polishing effect of the photosensitive drum is reduced. However, there was a problem that the polishing did not reach the intermediate transfer member and a sufficient polishing effect could not be obtained.

Therefore, the present invention has been made to solve the above-mentioned problems of the prior art, and an object of the present invention is to increase the size of the apparatus and the cost of the intermediate transfer member without increasing the cost. A sufficient polishing effect can be obtained, the occurrence of damage such as chipping or inversion (turning) of the cleaning elastic blade can be suppressed, and the life of the cleaning elastic blade can be prolonged. An object of the present invention is to provide an image forming apparatus capable of forming an image with good image quality.

[0017]

According to an aspect of the present invention, a toner image of a predetermined number of colors is sequentially formed on an image carrier, and the toner image is formed on the image carrier. After a toner image of a predetermined number of colors formed sequentially is primary-transferred on an intermediate transfer member in a multiplex manner, a toner image of a predetermined number of colors primary-transferred on the intermediate transfer member is secondarily transferred on a transfer member. In the image forming apparatus capable of forming an image, a cleaning unit that presses against the surface of the intermediate transfer body to remove the adhered matter attached to the surface of the intermediate transfer body, Abrasive supply means for supplying an abrasive, when cleaning, supplying an abrasive by the abrasive supply means to the surface of the intermediate transfer body, by the abrasive at the contact portion of the cleaning means and the intermediate transfer body, Polishing the surface of the intermediate transfer member It is those, which is configured as.

According to a second aspect of the present invention, the supply operation of the abrasive by the abrasive supply means is controlled according to environmental conditions and / or image forming conditions. Item).

Further, the invention described in claim 3 is characterized in that an application unit for applying a low surface energy substance to the surface of the intermediate transfer member is provided downstream of the cleaning unit in the moving direction of the intermediate transfer member. The image forming apparatus according to claim 1 or 2, wherein

[0020]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 2 shows a color electrophotographic copying machine as an image forming apparatus to which the cleaning device according to the embodiment of the present invention is applied.

In FIG. 2, reference numeral 1 denotes a main body of a color electrophotographic copying machine, and an original 2 is automatically conveyed to the upper portion of the main body 1 of the color electrophotographic copying machine in a state where documents 2 are separated one by one. An automatic document feeder 3 and a document reading device 4 for reading an image of the document 2 conveyed by the automatic document feeder 3 are provided. This document reading device 4
The original 2 placed on the platen glass 5 is illuminated by the light source 6, and a reflected light image from the original 2 is transmitted through a reduction optical system including a full-rate mirror 7, half-rate mirrors 8 and 9, and an imaging lens 10. Scanning exposure is performed on an image reading element 11 composed of a CCD or the like, and the color reading light image of the document 2 is scanned by the image reading element 11 at a predetermined dot density (for example,
(16 dots / mm).

The color material reflected light image of the original 2 read by the original reading device 4 is, for example, original reflectance data of three colors of red (R), green (G), and blue (B) (each of 8 bits). Is sent to the image processing apparatus 12, and the image processing apparatus 12 performs shading correction, position shift correction, lightness / color space conversion, gamma correction, frame erasure, color / movement editing on the reflectance data of the document 2. And other predetermined image processing.

The image data subjected to the predetermined image processing by the image processing device 12 as described above includes yellow (Y), magenta (M), cyan (C), and black (B
K) ROS13 (Raster Output Scann) as four-color original color material gradation data (8 bits each)
er), and the ROS 13 performs image exposure using laser light according to the original color material gradation data. Note that the color electrophotographic copying machine is configured to also function as a printer. After data is input and subjected to predetermined image processing by the image processing device 12, the image data is output to the ROS 13 as original color material gradation data of four colors.

An image forming means A capable of forming a plurality of toner images of different colors is provided inside the main body 1 of the color electrophotographic copying machine. The image forming unit A mainly includes a photosensitive drum 17 as an image carrier on which an electrostatic latent image is formed, and a plurality of images having different colors by developing the electrostatic latent image formed on the photosensitive drum 17. And a rotary developing device 19 as a developing means capable of forming a toner image of the type described above.

As shown in FIG. 2, the ROS 13 modulates a semiconductor laser (not shown) according to original color material gradation data, and emits a laser beam LB from the semiconductor laser according to gradation data. The laser beam LB emitted from the semiconductor laser is deflected and scanned by the rotary polygon mirror 14 and is scanned and exposed on the photosensitive drum 17 as an image carrier via the f · θ lens 15 and the reflection mirror 16.

The photosensitive drum 17 on which the laser beam LB is scanned and exposed by the ROS 13 is driven to rotate at a predetermined speed in a direction indicated by an arrow by driving means (not shown). The surface of the photosensitive drum 17 is
After being charged to a predetermined polarity (for example, negative polarity) and potential by the primary charging scorotron 18 in advance, a laser beam LB is scanned and exposed according to the original color material gradation data to form an electrostatic latent image. Is done. The electrostatic latent image formed on the photosensitive drum 17 is yellow (Y),
Magenta (M), cyan (C), black (BK) 4
The developing unit 19 of a rotary system rotatably provided with the developing units 19Y, 19M, 19C, and 19BK of the colors is reversely developed by, for example, a toner charged to a negative polarity having the same polarity as the charged polarity of the photosensitive drum 17, and Toner image of the color The toner image formed on the photosensitive drum 17 is charged with a negative polarity or the like by a pre-transfer charger 20 as necessary, and the charge amount is adjusted.

The toner images of the respective colors formed on the photosensitive drum 17 are placed on an intermediate transfer belt 21 as an intermediate transfer member disposed below the photosensitive drum 17 as a primary transfer means as a first transfer means. The image is multiply transferred by the transfer roll 22. The intermediate transfer belt 21 is
3. The driven roll 24a, the driven roll 24b, the tension roll 24c, the driven roll 24d, and the backup roll 2 as an opposing roll constituting a part of the secondary transfer means
5, the photosensitive drum 17 is supported rotatably in the direction of the arrow at the same moving speed as the peripheral speed of the photosensitive drum 17.

On the intermediate transfer belt 21, yellow (Y), magenta (M), cyan (C), and black (BK) are formed on the photosensitive drum 17 according to the color of the image to be formed. All or some of the four color toner images are
The images are transferred by the primary transfer roll 22 in a state of being sequentially superposed. The toner image transferred onto the intermediate transfer belt 21 is transferred to a transfer sheet 26 as a transfer member which is conveyed to a secondary transfer position at a predetermined timing. The transfer is performed by the press-contact force and the electrostatic force of the secondary transfer roll 27 that forms a part of the secondary transfer unit that presses against the backup roll 25. The transfer paper 26 is, as shown in FIG.
Paper feed cassettes 28 and 29 as a plurality of transfer paper housing members disposed at a lower portion in the color electrophotographic copying machine main body 1;
A sheet of a predetermined size from one of the sheets 30 and 31 is fed by the feed rolls 28a, 29a, 30a and 31a. The fed transfer paper 26 is transported to the secondary transfer position of the intermediate transfer belt 21 at a predetermined timing by a plurality of transport rolls 32 and registration rolls 33. And, as described above, on the transfer paper 26,
The backup roll 25 and the secondary transfer roll 27 as the secondary transfer means transfer a toner image of a predetermined color from the intermediate transfer belt 21 at a time.

The transfer paper 26 on which the toner image of a predetermined color has been transferred from the intermediate transfer belt 21 is separated from the intermediate transfer belt 21 and then conveyed to a fixing device 35 by a conveyance belt 34. The toner image is fixed onto the recording paper 26 by heat and pressure by the fixing device 35, and in the case of one-sided copying, the toner image is discharged onto the paper discharge tray 36 as it is, and the copying process of the color image is completed.

On the other hand, in the case of double-sided copying, the transfer sheet 26 on which the color image is formed on the first side (front side) is not discharged onto the discharge tray 36 as it is, but is conveyed downward by a reversing gate (not shown). The direction is changed, and the three rolls are once conveyed to the reversing path 39 by the tri-roll 37 and the reversing roll 38 pressed against each other. Then, the transfer sheet 26 is conveyed to the two-sided passage 40 by the reversing roll 38 which is reversed this time, and is once conveyed to the registration roll 33 by the conveying rolls 41 provided in the two-sided passage 40 and stopped there. The transfer paper 26 is again conveyed by the registration roll 33 in synchronization with the toner image on the intermediate transfer belt 21, and the transfer / fixing process of the toner image on the second surface (back surface) of the transfer paper 26 is performed. After the operation is performed, the sheet is discharged onto the discharge tray 36.

In FIG. 2, reference numeral 42 denotes a cleaning device for removing residual toner, paper dust and the like from the surface of the photosensitive drum 17 after the completion of the transfer process, and reference numeral 43 denotes a manual feed tray.

FIG. 3 is a block diagram showing the image forming means A of the color electrophotographic copying machine.

In this color electrophotographic copying machine, as described above, after the surface of the photosensitive drum 17 is uniformly charged to a predetermined potential by the scorotron 18 for primary charging,
An image corresponding to a predetermined color is exposed on the surface of the photosensitive drum 17 by the ROS 13 to form an electrostatic latent image. The electrostatic latent images formed on the surface of the photosensitive drum 17 corresponding to each color are developed by the developing units 19Y and 19 of the corresponding colors.
The toner image T is developed by M, 19C, and 19BK, and a toner image T of a predetermined color is formed on the surface of the photosensitive drum 17.

For example, if the electrostatic latent image formed on the photosensitive drum 17 corresponds to yellow, the electrostatic latent image is developed by the yellow developing unit 19Y and On the surface 17, a yellow toner image T is formed. Also, for the other magenta, cyan, and black colors, toner images T of corresponding colors are sequentially formed on the photosensitive drum 17 by the same process.

The toner image T of each color sequentially formed on the photosensitive drum 17 is transferred from the photosensitive drum 17 to the intermediate transfer belt 21 at a primary transfer position where the photosensitive drum 17 and the intermediate transfer belt 21 are in contact with each other. Transferred to the surface.
At this primary transfer position, a semi-conductive primary transfer bias roll 22 is disposed on the back side of the intermediate transfer belt 21, and the intermediate transfer belt 21 is moved by the primary transfer bias roll 22 to the photosensitive member. It comes into contact with the surface of the drum 17. A voltage having a polarity opposite to the charge polarity of the toner is applied to the bias roller 22 for the primary transfer, and the toner image T formed on the photosensitive drum 17 is transferred onto the intermediate transfer belt 21 by a pressing force and an electrostatic force. Is done.

In the case of forming a monochromatic image, the toner image T of a predetermined color primary-transferred onto the intermediate transfer belt 21 is
Immediately after the secondary transfer onto the recording paper 26, if a color image in which a plurality of color toner images T are superimposed is formed, a predetermined color toner image T is formed on the photosensitive drum 17 and the toner image is formed. The process of the primary transfer of the image T onto the intermediate transfer belt 21 is repeated for a predetermined number of colors.

For example, when a full-color image is formed by superimposing four color toner images T of yellow (Y), magenta (M), cyan (C), and black (BK), the photosensitive drum 17 , For each rotation, yellow (Y), magenta (M), cyan (C), black (B
The toner images T of each color K) are sequentially formed, and these four color toner images are sequentially primary-transferred onto the intermediate transfer belt 21 in a superimposed state.

At this time, the intermediate transfer belt 21 rotates at a period synchronized with the photosensitive drum 17 while holding the yellow unfixed toner image T which has been primarily transferred first.
On the intermediate transfer belt 21, an unfixed toner image T of magenta, cyan, and black is formed every one rotation thereof.
The image is transferred in a state of being sequentially superimposed on the yellow unfixed toner image T.

The unfixed toner image T primarily transferred to the intermediate transfer belt 21 in this manner is transported to a secondary transfer position facing the transport path of the transfer paper 26 with the rotation of the intermediate transfer belt 21. You.

The transfer paper 26 is fed from feed cassettes 28, 29, 30, and 31 by feed rolls 28a, 29a, 30a, and 31a as described above.
3 and the secondary transfer roll 27 and the intermediate transfer belt 21 are moved by the registration roll 33 at a predetermined timing.
Is fed between the nip portions.

On the back side of the intermediate transfer belt 21 at the secondary transfer position, a backup roll 25 serving as a counter electrode of the secondary transfer roll 27 is provided. At the secondary transfer position, a semi-conductive secondary transfer roll 27 is pressed against the intermediate transfer belt 21 at a predetermined timing, and a voltage having a polarity opposite to the charge polarity of the toner is applied to the backup roll 25 to thereby perform the intermediate transfer. The unfixed toner image T transferred onto the belt 21 is electrostatically secondarily transferred onto the transfer paper 26 at the secondary transfer position.

In this embodiment, as shown in FIG.
Instead of directly applying a voltage having the same polarity as the charge polarity of the toner to the secondary transfer roll 27, the transfer bias is applied by the bias roll 44 to the backup roll 25 pressed against the secondary transfer roll 27 via the intermediate transfer belt 21. A voltage having the same polarity as the charging polarity of the toner is applied from a transfer bias high voltage power supply (not shown) as a voltage applying unit. However, it is a matter of course that the secondary transfer roll 27 may be configured to directly apply a voltage having a polarity opposite to the charge polarity of the toner.

Then, the transfer paper 26 onto which the unfixed toner image T has been transferred is peeled off from the intermediate transfer belt 21 and is fixed by the electrode member 45, the guide plate 46 and the transport belt 34 disposed downstream of the secondary transfer portion. The image is sent to the device 35, and the fixing process of the unfixed toner image T is performed.

The intermediate transfer belt 21 is made of polyimide,
An appropriate amount of a conductive agent such as carbon black is dispersed in a synthetic resin such as polycarbonate, polyester, or polypropylene, or various rubbers, so that the volume resistivity is 10 ⁶ to 1.
Is formed by adjusting the film-like belt such that 0 ¹⁴ Ω · cm. The thickness of the intermediate transfer belt 21 is set to, for example, 0.1 mm. The circumference of the intermediate transfer belt 21 is set to an integral multiple (for example, three times) of the circumference of the photosensitive drum 17.

The secondary transfer roll 27 is disposed so as to be able to contact and separate from the intermediate transfer belt 21 as necessary. When a color image is formed, the final unfixed toner image is formed. T is separated from the intermediate transfer belt 21 until T is primarily transferred onto the intermediate transfer belt 21.

Further, the secondary transfer roll 27 has a surface layer made of a urethane rubber tube in which carbon is dispersed, and an inner layer made of foamed urethane rubber in which carbon is dispersed. Is coated with fluorine. The secondary transfer roll 27 is formed such that its volume resistivity is set to 10 ³ to 10 ¹⁰ Ω · cm, and the roll diameter is φ28 mm.
The hardness is set to, for example, 30 ° (Asuka C).

On the other hand, the backup roll 25 has a surface layer made of a blended rubber tube of EPDM and NBR in which carbon is dispersed, and an inner layer made of EPDM rubber, and has a surface resistivity of 10 ⁷ to 10 ⁷ . 10 ¹⁰ Ω
/ □, formed so that the roll diameter is φ28 mm,
The hardness is set to, for example, 70 ° (Asuka C).

The electrode member 45 disposed downstream of the nip portion at the secondary transfer position is preferably a sheet metal as a conductive plate member. In this embodiment, a 0.5 mm thick stainless steel plate is used. In this case, the transfer paper 26 having a needle shape is used. Further, 2 of the electrode member 45
The leading end on the side of the next transfer area is located 1 mm away from the line formed by the nip portion of the backup roll 25 and the secondary transfer roll 27 on the side of the secondary transfer roll 27 and 7 mm away from the exit of the nip portion.

By the way, in the color electrophotographic copying machine according to this embodiment, as shown in FIGS. 1 and 2, the residual toner or paper dust adhered to the surface of the intermediate transfer belt 21 as a member to be cleaned is attached. Cleaning device 5 for removing kimono
0 is provided. The cleaning device 50 includes a cleaning blade 51 made of an elastic body that presses against the surface of the intermediate transfer belt 21 that moves at a predetermined speed and removes deposits on the surface of the intermediate transfer belt 21.
During cleaning, the cleaning blade 51 starts pressure contact with the surface of the intermediate transfer belt 21 while the intermediate transfer belt 21 is moving, and stops at a predetermined pressure contact state to stop the surface of the intermediate transfer belt 21. It is designed to remove deposits.

The cleaning blade 51 of the cleaning device 50 normally waits at a position separated from the intermediate transfer belt 21 until a final toner image is transferred onto the intermediate transfer belt 21. The toner image transferred onto the transfer belt 21 is not disturbed. Then, the cleaning blade 5
After the final toner image is transferred onto the intermediate transfer belt 21, 1 is pressed against the surface of the intermediate transfer belt 21,
Adhered matter such as residual toner and paper dust adhered to the surface of the intermediate transfer belt 21 is removed.

FIG. 3 is a configuration diagram showing a cleaning device according to an embodiment of the present invention.

In FIG. 3, reference numeral 50 denotes a cleaning device. The cleaning device 50 is arranged near the upstream side of the driving roll 23 for driving the intermediate transfer belt 21 of the color electrophotographic copying machine. The cleaning device 50 is provided with a cleaning blade 51 that presses against the surface of the intermediate transfer belt 21 at a predetermined timing to remove extraneous matter such as residual toner and paper dust adhered to the surface of the intermediate transfer belt 21. . As the cleaning blade 51, for example, an elastic body such as polyurethane having a thickness of 2 mm is used. However, the thickness and the material of the blade 51 are not limited to this. The cleaning blade 5
1 is fixed to a sheet metal 52 having a substantially L-shaped cross section by bonding or the like. The sheet metal 52 to which the cleaning blade 51 is fixed is made of a metal bent at a small angle at the center. It is attached to the pressing plate 53 by means such as welding or bolting. The pressing plate 53
Is rotatable about a fulcrum 54, and an eccentric cam 56 is in contact with a pressing portion 55 extending above the pressing plate 53. The pressing plate 53 is
It is urged by a spring or the like (not shown) in the direction in which it comes into pressure contact with the eccentric cam 56, that is, in the clockwise direction. And
The cleaning device 50 rotates the eccentric cam 56 by a predetermined amount at a predetermined speed by a drive motor and a drive gear (not shown), and moves the pressing portion 55 of the pressing plate 53 clockwise by the eccentric cam 56. By
As shown in FIG. 4, the cleaning blade 51 attached to the pressing plate 53 via the sheet metal 52 is configured to be pressed against the surface of the intermediate transfer belt 21. In addition, the cleaning device 50 rotates the eccentric cam 56 by a predetermined amount at a predetermined speed by a drive motor and a drive gear (not shown).
The cleaning blade 51 attached to the pressing plate 53 via the metal plate 52 is moved away from the surface of the intermediate transfer belt 21 as shown in FIG. Is configured. As described above, the cleaning blade 51 rotates the eccentric cam 56 so that the intermediate transfer belt 2
Advance (contact) and retract (separation) for 1
Mounted as possible.

Further, the cleaning device 50 has a storage section 57 for storing the deposits such as residual toner and paper dust removed by the cleaning blade 51, and the storage section 57 has a substantially U It is formed in a character shape. Further, when a certain amount of deposits such as residual toner and paper dust removed by the cleaning blade 51 is accumulated in the storage portion 57, the accumulated attachment is rotated by a predetermined timing. An auger 58 for transporting the kimono to the outside of the cleaning device 50 is provided.

Further, the cleaning device 50 prevents the adhered matter such as residual toner and paper powder removed by the cleaning blade 51 from leaking outside.
A seal member 59 is provided for sealing an opening of the storage section 57 on the side facing the cleaning blade 51.
As the sealing member 59, for example, a thickness of 100 μm
A degree of mylar film is used. One end of the seal member 59 is fixed to a pivot member 61 that pivots about a fulcrum 60.
Is linked with a pressing plate 53 to which a cleaning blade 51 is attached via a link mechanism (not shown),
With the rotation of the pressing plate 53, the pressing plate 53 rotates counterclockwise. Then, the sealing member 59
As shown in FIG. 4, the cleaning blade 51 is also configured to press against the surface of the intermediate transfer belt 21 in conjunction with the operation of pressing the cleaning blade 51 against the surface of the intermediate transfer belt 21.

The housing section 57 of the cleaning device 50 has a structure in which the cleaning blade 51
It may be configured to move toward the intermediate transfer belt 21 in accordance with the operation of pressing against the intermediate transfer belt 21.

The cleaning blade 51 is a so-called doctor blade as shown in FIG. Here, as shown in FIG. 5, the doctor blade is such that the leading end of the blade 51 is pressed against the upstream side in the moving direction of the intermediate transfer belt 21 and the rear end side of the blade 51 is located downstream in the moving direction of the intermediate transfer belt 21. And the rear end side of the blade 51 is inclined with respect to the surface of the intermediate transfer belt 21. Since the cleaning blade 51 is made of an elastic material such as polyurethane, when the cleaning blade 51 is pressed against the surface of the intermediate transfer belt 21 by a predetermined amount, as shown in FIG. When pressed against the surface, it has a curved shape that curves downward.

In this embodiment, as described above, the cleaning blade 51 is a polyurethane blade, and as shown in FIG.
Thickness t = 2 mm, width l = 15 mm, free length L = 10 m
m, the length is formed to be substantially the entire width of the intermediate transfer belt 21, and its setting angle (hereinafter, referred to as “SA”) is 1
7 °, the bite amount into the intermediate transfer belt 21 (hereinafter referred to as “nip amount”) is set to 1.1 mm. However, the SA and the nip amount of the cleaning blade 51 are
Of course, other values may be set. Further, as described above, a sheet metal 52 made of stainless steel, aluminum, or the like is fixed to the surface side of the base end portion of the cleaning blade 51 by bonding or the like. By being attached to the pressing plate 53, the setting angle SA is set so as to be in the above-mentioned setting angle SA in a state of being pressed against the intermediate transfer belt 21.

By the way, in this embodiment, there is provided abrasive supply means for supplying an abrasive to the surface of the intermediate transfer member.
At the time of cleaning, an abrasive is supplied to the surface of the intermediate transfer body by an abrasive supply means, and the surface of the intermediate transfer body is polished by the abrasive at a contact portion between the cleaning means and the intermediate transfer body. ing.

That is, in this embodiment, as shown in FIG. 1, an abrasive supply device 70 for supplying an abrasive to the surface of the intermediate transfer belt 21 is provided. The position where the abrasive supply device 70 is provided is set downstream of the photosensitive drum 17 and upstream of the cleaning device 50 in the rotation direction of the intermediate transfer belt 21. In the illustrated embodiment, the abrasive supply device 70 is disposed below the steering roll 24c around which the intermediate transfer belt 21 is stretched. The abrasive supply device 70 includes a foam elastic roll 71 which is in contact with the surface of the intermediate transfer belt 21 and is rotatably disposed. The foamed elastic roll 71 is formed of, for example, a foamed elastic body made of a synthetic resin such as urethane or silicone rubber. A blade 72 made of urethane, metal, or the like is arranged on the surface of the foam elastic roll 71 so as to touch the belly. The inside of the abrasive supply device main body 73 is an abrasive reservoir 75 containing an abrasive 74, and the abrasive 74 attached to the foamed elastic roll 71 is regulated by a blade 72 from the abrasive reservoir 75l. An abrasive 74 is supplied (applied) to the surface of the intermediate transfer belt 21 by pressing and rotating the foam elastic roll 71 against the surface of the intermediate transfer belt 21.

The method of supplying the abrasive by the abrasive supply device 70 is not limited to the method using the foamed elastic roll 71 described above. For example, the abrasive is supplied by a combination of a rotationally driven brush and a flicker bar. The abrasive adhering to the brush from the abrasive pool is regulated to a small amount by a flicker bar, and the brush is brought into contact with the surface of the intermediate transfer belt 21,
It is a matter of course that another supply system may be adopted, such as a configuration in which the abrasive is supplied (applied) to the surface of the intermediate transfer belt 21 by being driven to rotate.

As the polishing agent 74, various known polishing agents can be used, and fluorine-containing cerium oxide having a volume average particle diameter of 0.3 to 6 μm is particularly preferable.

The abrasive supply device 70 can be moved by a retract mechanism (not shown) in a direction in which the foamed elastic roll 71 comes into contact with or separates from the surface of the intermediate transfer belt 21.

With the above configuration, the image forming apparatus according to this embodiment can obtain a sufficient polishing effect on the surface of the intermediate transfer member without increasing the size of the apparatus and increasing the cost as follows. It is possible to suppress the occurrence of damage such as chipping or reversal (turning) of the cleaning elastic blade, and it is possible to extend the life of the cleaning elastic blade and to form an image with good image quality. It has become.

That is, in the case of the color electrophotographic copying machine according to this embodiment, as shown in FIGS.
A color or black-and-white image can be formed on an OHP sheet for an overhead projector, a postcard, or an ultra-thick paper having a basis weight of 200 g / m ² or more, in addition to the transfer paper 26 made of ordinary plain paper as a transfer member. It is possible to do. In the above color electrophotographic copying machine, the intermediate transfer belt 21 is rotated at a normal process speed of 220.
(Mm / sec), the normal mode in which the image is transferred and fixed, and the process speed at the time of image transfer and fixing, which is slower than the normal 220 (mm / sec).
A deceleration mode (super cardboard mode) for changing to 0 (mm / sec) is provided.

In the above-described color electrophotographic copying machine, when an image is formed on transfer paper 26 made of ordinary plain paper, as shown in FIG. 6, the intermediate transfer belt 21 is set at 220 (mm / sec). After rotating at a process speed to sequentially transfer toner images of respective colors of yellow, magenta, cyan, and black from the photosensitive drum 17 onto the intermediate transfer belt 21, yellow, magenta, cyan, black, and the like are transferred from the intermediate transfer belt 21. Is transferred to the transfer sheet 26 at the secondary transfer position, as shown in FIG. In the color electrophotographic copying machine, when forming an image on the transfer member 26 made of an ultra-thick paper such as an OHP sheet or a postcard, the intermediate transfer belt 21 is set to 220 (mm / sec).
After the toner images of the respective colors of yellow, magenta, cyan, and black are sequentially transferred from the photosensitive drum 17 onto the intermediate transfer belt 21, the intermediate transfer belt is rotated as shown in FIG. 21 is set to 60 (mm / sec), which is slower than normal 220 (mm / sec).
/ Sec) to transfer a toner image of a predetermined color such as yellow, magenta, cyan, and black from the intermediate transfer belt 21 onto a transfer member 26 such as an OHP sheet or a thick paper at a secondary transfer position. It is configured such that an image can be satisfactorily transferred and fixed even to a transfer member 26 made of super thick paper such as an OHP sheet or a postcard.

As described above, the color electrophotographic copying machine has the normal mode and the deceleration mode (cardboard mode). In the color electrophotographic copying machine, an OHP sheet, a postcard, or a basis weight of 200 g /
When an image is formed on thick paper of m ² or more, the toner image transferred on the intermediate transfer belt 21 can be secondarily transferred to a super-thick paper such as an OHP sheet or a postcard. The secondary transfer voltage applied to the backup roll 25 is set to about 2.7 kV, which is much higher than usual.

Therefore, in the above-described color electrophotographic copying machine, when the toner image is transferred onto the transfer member 26 made of thick paper, an OHP sheet, or the like, the transfer member 26 is moved to the SE position.
When transported by F (short edge feed: short feed), a portion where the transfer member 26 is not interposed inevitably occurs in a region where the backup roll 25 and the secondary transfer roll 27 are pressed against each other via the intermediate transfer belt 21. . In a region where the backup roll 25 and the secondary transfer roll 27 are in direct pressure contact with each other via the intermediate transfer belt 21, a discharge is generated between the secondary transfer roll 27 and the intermediate transfer belt 21 by a minute gap, and the intermediate transfer belt The discharge products adhere to the surface of the intermediate transfer belt 21 or the surface of the intermediate transfer belt 21 is damaged by the discharge phenomenon, so that the friction coefficient increases.

Therefore, in this embodiment, when the cleaning device 50 other than the image forming process is operating,
The abrasive 74 is supplied to the surface of the intermediate transfer belt 21 by the abrasive supply device 70, and the abrasive 74 supplied to the surface of the intermediate transfer belt 21 is
Together with the cleaning device 50. The abrasive 74 supplied to the surface of the intermediate transfer belt 21 adheres to the edge of the cleaning blade 51 at the contact portion between the cleaning blade 51 of the cleaning device 50 and the intermediate transfer belt 21, and the abrasive 74 7
4, the surface of the intermediate transfer belt 21 is polished to remove discharge products and to smooth the surface. Therefore, the surface of the intermediate transfer belt 21 is
The coefficient of friction is kept low.

Therefore, since the surface of the intermediate transfer belt 21 has a low friction coefficient, even if the cleaning blade 51 contacts or separates from the surface of the intermediate transfer belt 21 during the movement of the intermediate transfer belt 21, The frictional force Fm generated between the cleaning blade 51 and the surface of the intermediate transfer belt 21 can be suppressed to a small value, and the occurrence of chipping or inversion at the edge of the cleaning blade 51 can be suppressed. As a result, a mechanism for collecting the discharge products and the like collected by the polishing means is unnecessary, and the intermediate transfer belt 21 can be used without increasing the size and cost of the apparatus.
A sufficient polishing effect on the surface can be obtained, and damage such as chipping or inversion (turning) of the cleaning blade 51 can be suppressed, and the life of the cleaning blade 51 can be extended.

Second Embodiment In the second embodiment, the supply operation of the abrasive by the abrasive supply means is controlled in accordance with the environmental condition and / or the image forming condition.

In the second embodiment, a coating means for applying a low surface energy substance to the surface of the intermediate transfer member is provided downstream of the cleaning means in the moving direction of the intermediate transfer member.

That is, in the second embodiment, as shown in FIG. 7, a temperature / humidity sensor 80 for detecting the temperature and humidity in the color electrophotographic copying machine main body 1 is provided, and plain paper or thick paper is used. There is provided a means for identifying the type of paper such as a paper or an OHP sheet.

Further, in the third embodiment, as shown in FIG. 7, an application means 81 for applying a low surface energy substance to the surface of the intermediate transfer belt 21 is provided. The application means 81 is composed of an application roll 82 impregnated with dimethyl silicone oil as a low surface energy substance. The application roll 82 is formed of, for example, silicon rubber or the like. Further, the application roll 82
Is rotatably supported, and can be brought into contact with and separated from the surface of the intermediate transfer belt 21 wound around the drive roll 23 by the contact / separation mechanism 83.

In the second embodiment, the temperature and humidity in the color electrophotographic copying machine main body 1 are detected by the temperature and humidity sensor 80. For example, in a high temperature and high humidity environment, the surface of the intermediate transfer belt 21 is polished. The polishing interval is shortened by the agent 74.
In the color electrophotographic copying machine, when forming an image on the transfer member 26 such as thick paper other than plain paper or an OHP sheet, the interval at which the surface of the intermediate transfer belt 21 is polished by the abrasive 74 is shortened. Be composed.

After the surface of the intermediate transfer belt 21 is polished with the abrasive 74, a low surface energy substance is applied to the surface of the intermediate transfer belt 21 by the application means 81.

More specifically, apart from a counter for counting the number of ordinary prints, an application interval for supplying an abrasive to the surface of the intermediate transfer belt 21 and at the same time determining an interval for applying a low surface energy substance is determined. A counter 84 is provided.

In the plain paper mode, the CPU 85
Sets the drive motor 86 for driving the intermediate transfer belt 21 to 2
While driving at full speed at 20 mm / sec, a low voltage (for example, 1.3 kV) is applied to the backup roll 25 via the high voltage power supply 87 for secondary transfer to form and transfer an image. Counter C _AI 84
Is advanced by a predetermined value.

In the thick paper / OHP mode, the CPU
85 is a drive motor 86 for driving the intermediate transfer belt 21
Is decelerated at 60 mm / sec, and a high voltage (for example, 2.7 kV) is applied to the backup roll 25 via the high voltage power supply 87 for secondary transfer to form and transfer an image and print one sheet. Every time, the application interval counter C _AI 84 is advanced by a predetermined value.

When the value of the application interval determination counter C _AI 84 exceeds the application execution threshold value S stored in the memory 88, the CPU 85 waits for the end of the job being executed and waits for the end of the job to be applied. Then, the application roller 82 is brought into contact with the surface of the intermediate transfer belt 21 to apply the abrasive 74 and the low surface energy substance to the surface of the intermediate transfer belt 21, and the value of the counter C _AI 84 is returned to zero.

Further, if necessary, a temperature / humidity sensor 80 for detecting the temperature and humidity in the color electrophotographic copying machine is provided, and in a high-temperature and high-humidity environment, the application execution threshold S stored in the memory 88 is stored. By using the application execution threshold S2 in a high-temperature and high-humidity environment that is set to be smaller than the application execution threshold S1 in a normal environment, the application interval of the abrasive 74 and the low surface energy substance is shortened. You may.

In the second embodiment, the CPU 85
Monitors the drive current of the drive motor 86 that drives the intermediate transfer belt 21 at each printing with the ammeter 87, thereby detecting the drive torque of the intermediate transfer belt 21 and presetting the drive torque corresponding to a certain torque value T. and when exceeds the current value I _T without waiting for the end of the print job, the running printing ends, immediately suspended job, the surface of the supply roll 71 and applicator roll 82 intermediate transfer belt 21 To perform an operation of applying the abrasive 74 and the low surface energy substance to the surface of the intermediate transfer belt 21 to return the value of the counter C _AI 84 to zero, and then restart the job. Is also good.

Examples of the low surface energy substance applied to the surface of the intermediate transfer belt 21 include oils such as dimethyl silicone oil and amine-modified silicone oil described above, and unsaturated fatty acids such as oleamide. Can be used.

By doing so, the intermediate transfer belt 2
The surface of the cleaning blade 51 can be more reliably maintained at a low friction coefficient, and the cleaning blade 51 can be prevented from being damaged or chipped or turned upside down. Is possible.

The other structure and operation are the same as those of the first embodiment, and the description is omitted.

[0086]

As described above, according to the present invention,
It is possible to obtain a sufficient polishing effect on the surface of the intermediate transfer member without increasing the size and cost of the apparatus, and to suppress the occurrence of damage such as chipping or inversion (turning) of the cleaning elastic blade. Accordingly, it is possible to provide an image forming apparatus capable of prolonging the life of the cleaning elastic blade and forming an image with good image quality.

[Brief description of the drawings]

FIG. 1 is a configuration diagram showing an image forming unit of a color electrophotographic copying machine as an image forming apparatus according to Embodiment 1 of the present invention.

FIG. 2 is a configuration diagram showing a color electrophotographic copying machine as an image forming apparatus according to Embodiment 1 of the present invention.

FIG. 3 is a configuration diagram illustrating a cleaning device.

FIG. 4 is a configuration diagram showing a cleaning device.

FIGS. 5 (a) and 5 (b) are configuration diagrams each showing an installation state of a cleaning blade.

FIG. 6 is a timing chart showing an image forming operation.

FIG. 7 is a timing chart showing the driving speed of the intermediate transfer belt in the plain paper mode and the thick paper mode.

FIG. 8 is a configuration diagram showing an image forming unit of a color electrophotographic copying machine as an image forming apparatus according to Embodiment 2 of the present invention.

FIG. 9 is a configuration diagram illustrating an image forming unit of a conventional image forming apparatus.

FIGS. 10A to 10C are explanatory diagrams respectively showing states in which the cleaning blade is pressed against the intermediate transfer belt.

FIGS. 11A and 11B are explanatory views respectively showing a state in which the cleaning blade is in pressure contact with the intermediate transfer belt.

FIG. 12 is an explanatory diagram showing a state in which the cleaning blade is in pressure contact with the intermediate transfer belt.

FIG. 13 is a schematic view of an electron micrograph of a chip formed on an edge of a cleaning blade.

[Description of sign]

17: Photoreceptor drum (image carrier), 21: Intermediate transfer belt, 50: Cleaning device, 51: Cleaning blade, 70: Abrasive supply device, 71: Foam elastic roll,
72: blade, 73: abrasive supply device main body, 74: abrasive.

Continued on the front page (72) Inventor Shigehiko Hasenami 2274 Hongo, Ebina-shi, Kanagawa Prefecture Inside Fuji Xerox Co., Ltd. (72) Inventor Yoshinori Nakano 2274 Hongo, Ebina-shi, Kanagawa Prefecture Fuji Xerox Co., Ltd. (72) Inventor Osamu Handa 2274 Hongo, Ego-shi, Kanagawa Prefecture Fuji Xerox Co., Ltd. (72) Inventor Katsuya Takenouchi 2274 Hongo, Ebina-shi, Kanagawa Prefecture Fuji Xerox Co., Ltd. Inside Xerox Corporation (72) Inventor Yasutomo Ishii 2274 Hongo, Ebina City, Kanagawa Prefecture Inside Fuji Xerox Co., Ltd. (72) Inventor Satoshi Matsuzaka 2274 Hongo, Ebina City, Kanagawa Prefecture Inside Fuji Xerox Co., Ltd. (72) Inventor Yoshihiro Enomoto 2274 Hongo, Ebina-shi, Kanagawa Fuji Xerox Co., Ltd. (72) Inventor Junichiro Samejima 2274 Hongo, Ebina-shi, Kanagawa Fuji Xerox Co., Ltd. Term (Reference) 2H030 AD01 AD03 AD16 BB02 BB24 BB42 BB46 2H032 AA05 AA15 BA01 BA05 BA07 BA30 CA12 CA13 CA14

Claims (3)

[Claims] 1. A toner image of a predetermined number of colors is sequentially formed on an image carrier, and toner images of a predetermined number of colors sequentially formed on the image carrier are multiplexed and primary-transferred onto an intermediate transfer body. After doing
An image forming apparatus capable of forming an image by secondary-transferring a toner image of a predetermined number of colors primary-transferred onto the intermediate transfer body onto a transfer member, by pressing against the surface of the intermediate transfer body, Cleaning means for removing the deposits adhering to the surface of the intermediate transfer member, and abrasive supply means for supplying an abrasive to the surface of the intermediate transfer member; An image forming apparatus, wherein an abrasive is supplied by a supply unit, and the surface of the intermediate transfer body is polished by the abrasive at a contact portion between the cleaning unit and the intermediate transfer body. 2. The image forming apparatus according to claim 1, wherein an operation of supplying the abrasive by the abrasive supply unit is controlled according to environmental conditions and / or image forming conditions. 3. An apparatus according to claim 1, further comprising an application unit for applying a low surface energy substance to the surface of the intermediate transfer member, downstream of the cleaning unit in the direction of movement of the intermediate transfer member. An image forming apparatus according to any one of the preceding claims.