JP2003241533A - Image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image forming apparatus capable of preventing the deterioration of image quality by securing cleaning performance and transfer body charge eliminating ability while avoiding the complication of structure. <P>SOLUTION: The image forming apparatus is provided with an image carrier which has a movable surface and on which a latent image is formed, a intermediate transfer body for transferring a toner image formed on the image carrier to sheet material, a charge eliminating means abutting on the intermediate transfer body and charge-eliminating the intermediate transfer body by superposing AC bias, and an intermediate transfer body driving means for driving the intermediate transfer body. In the apparatus, the intermediate transfer body and the charge eliminating means abut on each other and an abrasive is not incorporated in an image forming agent, then a relative speed difference is made between driving speed for the intermediate transfer body and that for the charge-eliminating means. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

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

[0002]

2. Description of the Related Art Conventionally, various image forming apparatuses have been developed. In image forming apparatuses such as copying machines and laser beam printers, a toner image is formed on the surface of a photosensitive drum which is an image carrier, and the toner image is formed. In the system in which the image is transferred to a transfer material such as paper, the cleaning device removes the residual toner remaining on the surface of the photosensitive drum after the transfer of the toner image.

On the other hand, even in a color copying machine equipped with an intermediate transfer member for enhancing the selectivity of the transfer material, the untransferred toner remaining on the intermediate transfer member is removed by a cleaning device for the intermediate transfer member. There is.

As the cleaning device as described above,
For example, a cleaning blade having an elastic portion such as urethane rubber formed in a plate shape is provided, and the edge of the cleaning blade scrapes off the residual toner adhering to the surface of the photosensitive drum with a predetermined pressure.

A cleaning device using this cleaning blade has a relatively simple structure and is small in size, and has an advantage that it is excellent in toner removing performance although it is advantageous in terms of cost. In addition, especially in high-quality color image forming apparatuses that require high-speed and high-quality images, in order to minimize damage to the transfer body, a simpler light pressure type brush cleaner or a cleaner than a cleaning blade is used. There are some models that have introduced the cleaning-less type.

Recently, in response to the demand for higher image quality, the optimization and adjustment of the toner components in the image forming agent have been studied, and not only the particle size of the toner has been reduced, but also the external additive in the image forming agent. It has also been proposed that the amount be reduced to improve the fluidity and enhance the reproducibility of the highlight part.

[0007]

However, in the above-mentioned image forming apparatus, since the cleaning blade is brought into contact with the surface of the photosensitive drum, residual toner is strongly adhered to the cleaning blade as the image forming apparatus is used for a long period of time. There is a case where the particles adhere to cause so-called filming and deteriorate the subsequent image quality.

Further, in a recent image forming apparatus, when a general fixing device having a structure in which a transfer material is passed through a nip portion of a pair of rollers is used for fixing a toner image, the toner is prevented from adhering to the roller. Apply silicone oil to the roller surface to prevent it. This silicone oil is
When the toner image on the second surface is transferred, it adheres to the transfer device, and when the image on the next page is formed, it adheres to the intermediate transfer body.

The silicon oil adhering to the surface of the intermediate transfer member is partially transferred to the photosensitive drum which is in contact with the intermediate transfer member, and adheres to the photosensitive drum. There is a problem that it may come off to cause cleaning failure.

Further, in order to achieve high image quality by using the structure provided with the transfer member, as the setting of the cleaning mechanism on the transfer member as much as possible, light pressure, simplification, and use of toner having high transfer efficiency is used. Cleaner-less technology is being put to practical use on the premise of doing so. In this case, it is inevitable that the ability to remove the charged products remaining on the intermediate transfer member, the transfer oil, the paper dust, the dust, and the like must be reduced.

Further, if the contact pressure of the member for cleaning the toner on the intermediate transfer member is forcibly increased, the damage to the intermediate transfer member becomes large, and defects in image formation such as defective conveyance of the intermediate transfer member become remarkable. I don't like it.

[0012] Further, the retention of the electric memory by electrification becomes a factor that hinders image defects and long-term stabilization of image quality, and the residual toner having a charge on the intermediate transfer member has a drawback that it is difficult to clean.

Further, in a model using an intermediate transfer member, there is a problem that image quality is deteriorated by performing the transfer twice. Therefore, in order to enhance transferability of the toner to the intermediate transfer member as much as possible, In general, the intermediate transfer member and the intermediate transfer member are in constant contact with each other.

For example, in order to remove the residual charges on the intermediate transfer member, the contact pressure of the contact members such as the charge removing member and the cleaning member for removing the residual toner is made as small as possible, and the intermediate transfer member and the image are transferred. It is an indispensable subject not to give vibration to the carrier, and during the image formation, the rotation speed of the charge eliminating member can be varied to increase the relative speed difference with the image carrier and enhance the polishing property of the intermediate transfer member surface. This is a factor that hinders high-quality image formation, and it has become difficult to achieve both cleaning of the intermediate transfer member and high-quality image formation.

Therefore, in the conventional image forming apparatus,
At the same time, without complicating the structure, prevent filming due to long-term use and cleaning failure due to adhesion of silicone oil during fixing, and ensure cleaning performance and charge removal property of transfer medium at the same time with a simple intermediate transfer medium cleaning device. It was difficult to achieve and prevent the deterioration of image quality.

Further, in order to meet the recent demand for high stability of durability, the number of transfer endurance sheets of the transfer body continues to rise, and due to an increase in the friction coefficient between the transfer body and the cleaning member as the durability progresses, Many problems that are difficult to solve have come to be seen, such as waviness of the transfer belt system, color misregistration due to deformation, and machine down due to reverse rotation of the cleaning blade.

On the other hand, in recent years, the pursuit of high-quality images has become remarkable, and the particle size of the toner, which is the developer, has been reduced by increasing the speed of the image forming apparatus and rubbing the cleaning member. This is also a cause of worsening toner scattering inside the machine. In order to solve this problem, improvement of the air flow in the machine and electrostatic aggregation by increasing the electrostatic amount of toner have been the common solutions. However, there is a limit to the improvement of the airflow inside the aircraft. That is, when the suction force is increased, the scattered toner from the developing device or the waste toner from the waste toner box in the cleaning device is sucked out, and the periphery of the photosensitive drum or the intermediate transfer member, especially the belt-shaped intermediate transfer member is absorbed. There is a problem that the back surface (non-image forming image bearing member: inner side) is contaminated, which easily causes image defects due to transfer charging failure.

Further, in recent years, in order to ensure high image quality, particularly in order to maintain the reproducibility of the highlight portion, there is a tendency to reduce the amount of the abrasive that lowers the fluidity of the toner as much as possible.
As a result, the ability to remove foreign matters and the like on the surface of the transfer body is steadily decreasing, and therefore, a problem that becomes a starting point of image defects such as toner belt fusion and coat filming has become a significant problem.

The present invention has been made in view of the above problems. The object of the present invention is to avoid the complication of the structure while
An object of the present invention is to provide an image forming apparatus capable of ensuring the cleaning property and the charge removal property of a transfer body and preventing deterioration of image quality.

[0020]

To achieve the above object, the present invention provides an image carrier having a movable surface on which a latent image is formed, and a toner image formed on the image carrier. An intermediate transfer body for transferring to a sheet material, an intermediate transfer body contacting with the intermediate transfer body, a neutralizing means for superimposing an AC bias on the intermediate transfer body, and an intermediate transfer body driving means for driving the intermediate transfer body. In the image forming apparatus in which the intermediate transfer member and the charge removing unit are in contact with each other and the image forming agent does not contain an abrasive, a relative speed difference is generated between the intermediate transfer member and the drive speed of the charge removing. It is characterized by having.

[0021]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the accompanying drawings.

However, the dimensions, materials, shapes, relative positions, etc. of the constituent parts described in the present embodiment limit the scope of the present invention to them unless otherwise specified. is not.

<Embodiment 1> FIG. 1 is a sectional view of an essential part of an image forming apparatus according to the present invention. The image forming apparatus shown in FIG. 1 is a four-color full-color copying machine. Inside the apparatus main body 100), four image forming sections, that is, the first image forming section 4a, are arranged in this order from the upstream side to the downstream side along the rotational transport direction A of the photosensitive drum 1 as an image carrier. The second image forming unit 4b and the third image forming unit 4c
And a fourth image forming unit 4d.

As shown in FIG. 1, the first to fourth image forming sections 4a to 4d are provided with a photosensitive drum 1 which is a drum type electrophotographic photosensitive member as an image bearing member. Photosensitive drum 1
As for the above, a photosensitive layer having a carrier generating layer (CGL) and a carrier transporting layer (CTL) is coated on the surface of a cylindrical aluminum substrate, and the coating 1 and the JIS surface roughness (B601) are applied so that the thickness of the CTL is 40 μm. ) Rz (10
The point average) used was 2 μm or less in the initial state.

The photosensitive drum 1 is rotatably supported by the apparatus main body 100, and is rotationally driven in the direction of arrow A at a process speed of 120 mm / sec by a driving means (not shown). The photosensitive drum 1 has an outer diameter of 80 mm.
I used the one.

A primary charger 2 is arranged in proximity to the photosensitive drum 1, and the surface of the photosensitive drum 1 is uniformly charged by the primary charger 2. The surface of the photosensitive drum 1 after being charged is exposed by an optical system (toner image forming means) arranged above the image forming portion to form an electrostatic latent image, and then is exposed by the blank exposing portion 3.

Subsequently, the toner in the developer is attached to the electrostatic latent image by the first to fourth image forming units 4a to 4d,
It is developed as a toner image. As the developer, a two-component developer mainly composed of polyester toner and ferrite carrier was used.

This toner image is a photosensitive drum 1 and a linear pressure on the photosensitive drum 1 (divided by the member pressure applied in the thrust direction by the length in the drum thrust direction) 0.049
When the photosensitive drum 1 and the intermediate transfer belt 11, which is an intermediate transfer member that rotates in the forward direction, are pressed at N / cm and come to a transfer portion where they come into contact and face each other, they are formed by the pre-charged intermediate transfer belt 11. The action of the electric field causes the transfer from the photosensitive drum 1 to the intermediate transfer belt 11 in the form of electrostatic attraction.

Here, the contact pressure of the charge eliminating roller 21 as the charge eliminating means against the intermediate transfer belt 11 during the image formation is P
1. When the contact pressure is P2 during non-image formation, P1 = P
2> 0 is satisfied. Further, the static elimination roller 21 is provided with a static elimination roller facing earth member 22 at a position facing the static elimination roller 21.

EPDM rubber, chloroprene rubber, epichlorohydrin rubber, silicone rubber, NBR rubber, or modified rubbers thereof are used as the belt layer material in the above-mentioned intermediate transfer belt 11.

Further, as the material of the surface layer, a material containing a fluororesin (for example, from the viewpoint of high releasability and low coefficient of friction) (for example,
Material containing PVDF, PTFE, tetrafluoroethylene, etc.)
Is used.

FIG. 2 is a partially enlarged view of the intermediate transfer belt 11 shown in FIG. In the present embodiment, as shown in FIG. 2, EPDM rubber is used for the base layer 11a forming the intermediate belt 11, and the base layer 11a
Then, a coating in which PVDF resin was dispersed was coated to form the surface layer 11b.

EPDM rubber is used for the base layer which constitutes the static elimination roller 21, and carbon is dispersed and internally added as a conductive filler to this belt layer to obtain a hardness of 40 degrees (Asker C load 4.9 N) and an average surface roughness of 10 um. A product of about 20 um is used, and the surface layer is in contact with the intermediate transfer belt 11, and the electric resistance is 1.0 × 10 5 to 1.0 × 10 6 Ω or less.

The surface layers of the rollers facing each other with the intermediate transfer belt 11 sandwiched therebetween were made of the same material, and used as a member for discharging charges due to static elimination as ground. Both rollers have an outer diameter of 16 m
m, the thrust length was 306 mm, the contact pressure of the charge eliminating member on the intermediate transfer belt 11 was 3.92 N, and the average surface roughness was 6 μm to 10 μm.

The intermediate transfer belt 11 includes a primary transfer bias roller 8 facing the photosensitive drum 1, a support roller 9, a facing roller 10 facing the secondary transfer bias roller 12, and a facing roller 19 facing the cleaning blade 16.
The carriage is rotatably suspended in the direction of arrow B.

Further, as a cleaning means for the intermediate transfer belt 11, a cleaning blade 16 was brought into contact with the conveyance direction of the intermediate transfer belt 11 in the forward direction. As the material of the cleaning blade 16, polyurethane rubber was used.

The drive roller 19 which is connected to a drive source (not shown) and drives the intermediate transfer belt 11 has an electric resistance of 10Ω.
・ BIE on the surface layer with AL material of cm or less as core
(Butadiene isoprene EPDM) material was used, and the electrical resistance was 105 to 106 Ω · cm or less. The rubber hardness used in JIS-A was 50 ° or more.
The core metal was grounded. Also, the drive roller 19
The contact pressure with the static elimination roller 21 was 0.49 N / m.

After the toner image is transferred, the residual toner remaining on the surface of the photosensitive drum 1 without being transferred to the transfer material P is scraped off and removed by the cleaning blade 17 of the cleaning device 5, and further, by the pre-exposure lamp 15. The residual charges are removed, and the next image is formed.

The photosensitive drum 1 on which the first toner image is formed by the first image forming section 4a as described above is conveyed and rotated, and the second image forming section 4b and the third image forming section 4 are rotated.
c, and the first image forming unit 4d
As in the case of the image forming section 4a, the toner images are multiply developed.

However, the first to fourth image forming sections 4a to 4d
The toner color of the toner image developed by
Toner images of four colors are collectively transferred onto the intermediate transfer drum 11 by the primary transfer bias roller 8, and the transfer material P is transferred onto the secondary transfer bias roller 8 in time with the toner composite image on the intermediate transfer belt 11. The toner composite image is collectively transferred to the transfer material P, and the toner image is fixed on the transfer material P via the transfer material transfer path 18 to obtain a copy image.

At this time, for example, silicone oil is applied as a release agent to the surface of the fixing roller of the fixing means 14 so that the toner on the transfer material P does not adhere to the surface of the fixing roller. The transfer material P on which the toner image is formed on the front surface (first surface) passes above the flapper and is ejected onto the paper ejection tray when the image is formed on one side. As a result, when the image formation is performed on both sides, the transfer material P having the toner image fixed on the first side is guided to the lower sheet re-feeding unit by the switching of the flapper without being discharged to the sheet discharge tray. .

Then, after being turned upside down by the reversing device, the toner image is transferred again to the second surface, then the toner image is fixed by the fixing means 14 and discharged through the flapper onto the paper discharge tray. Image formation is completed.

After that, the photosensitive drum 1 performs three-rotation idle rotation operation (at-rotation), and at the same time, the intermediate transfer belt 11 which is in forward contact with the photosensitive drum 1 also performs a predetermined rotation operation.

The toner used here has a weight-average particle diameter of 3 to 7 μm, contains more than 40% by number of toner particles having a particle diameter of 5 μm or less, and 2 toner particles having a particle diameter of 4 μm or less. A blending of 20% by volume to 6% by volume of a toner having a particle size of 8 um or more and 6% by volume or less, and containing no abrasive particles (such as strontium oxide) in the toner. did.

Next, the operation of the image forming apparatus according to the present invention will be described with reference to FIG. 3 is an operation sequence diagram of the image forming apparatus according to the present invention.

As shown in FIG. 3, the rotational process speed of the intermediate transfer belt 11 is set to 133 mm in order to generate a rotational speed difference between the intermediate transfer belt 11 and the discharging roller 21, which is a feature of the present invention. / Sec to 170 mm
The speed was increased to / sec. Further, during the idling operation, the charge removal roller 21 is biased with a DC voltage of 3 kV and an AC voltage of 2 kV.
(Frequency of 1.5 Hz) was superimposed and applied.

Here, the charge eliminating roller 21 comes into contact with the intermediate transfer belt 11 in the forward direction.

Due to the generated relative speed difference, a frictional force is generated between the intermediate transfer belt 11 and the static elimination roller 21, an operation occurs in which the intermediate transfer belt 11 and the static elimination roller 21 mutually grind each other, and static elimination is performed. Vibration due to the voltage applied to the roller 21 makes it possible to remove foreign matter such as shavings and dust on the residual toner belt accumulated on the surface of the intermediate transfer belt 11 and the surface of the charge eliminating roller 21 as the number of times of image formation is accumulated. Highly stable image formation could be achieved.

Incidentally, in the present embodiment, the contact pressure of the cleaning blade 16 contacting the intermediate transfer belt 11 is 0.196 N / cm, and the environmental conditions are high temperature and high humidity.
According to the results of the durability test in an environment test room at 2 ° C and 75%, conventionally, at the time of 10,000 sheets, image defects such as image fusion toner sticking spots / streaks and oil streak cleaning defects, which are considered to be due to charged products, have occurred. However, it was confirmed that the good condition was maintained even after 40,000 sheets had passed.

Further, within 20,000 sheets, the transfer cleaning blade 16 was turned up due to an increase in the friction coefficient due to the surface roughness of the transfer belt surface portion, but it was still good even when the number of blades exchanged was 20,000. It was confirmed that it retains smooth rubbing property.

In the present experiment, evaluation was carried out by continuously copying an image with an image ratio of about 25% by A4 size transverse feed in the endurance mode.

<Second Embodiment> Next, a second embodiment of the present invention will be described.

Since the configuration of the present embodiment is substantially the same as the configuration of the first embodiment described with reference to FIG. 1, the detailed description of the configuration will be omitted.

The purpose of this embodiment is to avoid the constant injection of the sequence as in the first embodiment during non-image formation, and to keep the main focus of the first embodiment at a certain copy number interval. By improving the polishing ability by utilizing the relative speed difference, high image quality and high stability will be achieved.

The operation sequence of this embodiment will be described with reference to FIG. 4 is an operation sequence diagram of this embodiment.

However, as shown in FIG. 5, in this operation sequence, the number of polishing is naturally reduced as compared with the first embodiment, and this reduction must be covered by another means. Therefore, in the present embodiment, the process speed of one rotation of the intermediate transfer belt 11 in the non-image forming apparatus is increased to 250 mm / sec from 133 mm / sec at the time of image formation, and at the same time, the rotation of the discharging roller 21 is performed. Process speed is also 133 mm / sec to 1
This was achieved by pushing up to 50 mm / sec and increasing the number of polishing times between the intermediate transfer body 11 and the static elimination roller 21.

This embodiment is particularly effective for an image forming apparatus that does not have a double-sided continuous copy version. In the executed sequence, the sequence of this embodiment is input once every 5,000 copies. However, the present inventors endeavored to achieve a long life of the intermediate transfer belt 11 and the charge eliminating roller 21 without increasing the number of polishing times unnecessarily.

By the way, in the prior art, image blurring toner streaks and spots due to poor charging occurred at 20,000 sheets or less at 32 ° C. and 75% under a high temperature and high humidity environment. In the form, it is possible to confirm that the cleaning property is maintained up to 40,000 sheets by single-sided A4 size lateral feeding and intermittent copying of one sheet, and the transfer cleaning blade 16 also slides satisfactorily up to 40,000 exchanged sheets. It was confirmed that it retains sex.

<Third Embodiment> Next, a third embodiment of the present invention will be described.

The present embodiment is a further improvement of the effect of the second embodiment, and particularly corresponds to a high speed color copying machine having a faster process speed than the image forming apparatus described in the second embodiment. Is.

Therefore, its configuration is similar to that shown in FIG. Further, FIG. 5 shows a sequence diagram of the present embodiment.

In this embodiment, the process speed is 2
It was applied to a high-speed copying machine with a high speed of 00 mm / sec. A drum having a diameter of 180 mm was used in response to the speedup.

As the experimental evaluation, the same evaluation mode as in the above-described embodiment was used. In the conventional technique, filming occurred in 10,000 copies or less, but in the present embodiment, filming occurs. The process speed of the intermediate transfer belt 11 at the time of non-image formation is set to V2 = 250 mm / sec, which is higher than the process speed at the time of image formation, and the static elimination roller 24 is stopped. Can be removed.

By the way, the sequence of this embodiment is 5
By throwing in every 000 sheets, the target of 40,000 sheets could be achieved. At this time, A4 size horizontal feed,
It was a single intermittent copy. The image used has a duty ratio of 2
5% was used.

<Fourth Embodiment> Next, a fourth embodiment of the present invention will be described.

The configuration of this embodiment is similar to that of the first embodiment described with reference to FIG. The operation sequence of this embodiment will be described with reference to FIG. FIG. 6 is an operation sequence diagram of the image forming apparatus according to the fourth embodiment of the present invention.

The object of the present embodiment is, in particular, for the fusion streak spots of the image forming apparatus designed to eliminate the content of the abrasive in the toner in order to reduce the occurrence of filming. The main purpose is to suppress the occurrence of image defects such as.

Components of external additives in toner (especially abrasives)
Is to prevent damage to the photoconductor (durability, scratches, etc.), delay the occurrence of image defects such as vertical streaks due to scratches, and extend the life of the photoconductor, and to prevent deterioration of toner fluidity. In particular, it is possible to maintain the reproducibility of the highlight part, but on the other hand, the abrasion amount of the photoconductor is reduced, and the removal ability of the fusion products that hinder the charging ability of the photoconductor or transfer body surface is reduced. This causes abnormal images such as fused stripes and spots on the image.

Here, in this embodiment, as a countermeasure, especially in a high temperature and high humidity environment, a polishing force increasing sequence between the intermediate transfer belt 11 and the charge eliminating roller 21 which is seen in the above-described first embodiment is incorporated. At the same time, in order to improve the polishing power over the sequence other than in the high temperature and high humidity environment, a sequence in which the polishing power is changed in association with the environmental conditions in the apparatus is introduced.

On the other hand, when the polishing force is not required so much, for example, in a low temperature and low humidity environment, the polishing force is prevented from operating more than necessary, and the life around the transfer belt is unnecessarily reduced. I tried not to.

In the embodiment, the environmental conditions are divided into three categories, and I (internal temperature 20 ° C. to less than 30 ° C., humidity 10%)
~ Less than 60%), II (internal temperature 30 ° C to 45 ° C, humidity 6
0% to less than 80%) and III (in-machine temperature 45 ° C. or higher, humidity 80% or higher). Other combinations are assigned to categories with humidity values.

Under the environmental conditions of Category I, the process speed of the intermediate transfer belt in the above-described first embodiment during non-image formation was 170 mm / sec (see FIG. 6).

Under the environmental conditions of Category II, the process speed of the intermediate transfer belt during non-image formation is 190 mm.
/ Sec (see FIG. 6).

Under the environmental conditions of Section III, the process speed of the intermediate transfer belt 11 during non-image formation in the above-described Embodiment 1 was set to 220 mm / sec (see FIG. 6).

As a result, it is possible to increase the polishing force between the transfer belt 11 and the static elimination roller 21 in association with the environmental conditions with respect to the fusion streaks and spots that are likely to occur due to high temperature and high humidity. It is now possible to create an image stabilization sequence.

Further, the surface of the transfer belt is moderately roughened by the rotary polishing, and the flipping of the transfer cleaning blade 16 due to the process speed increase under the high temperature and high humidity environment can be prevented, and the expected harmful effects can be eliminated. It was possible to achieve the 4k number, which is a guideline for replacing the blade 16.

The same effect as described above can be achieved by forming a sequence corresponding to another environmental condition.

Corresponding to the environment classification in the image forming apparatus, in section I, the rotation speed of the intermediate transfer belt was set to 3 rotations. In Category II, the rotation speed of the intermediate transfer belt was set to four. In Category III, the rotation speed of the intermediate transfer belt was set to 5 times.

However, in the image forming apparatus according to the present invention, the number of rotations of the intermediate transfer belt is not limited to these numbers and may be changed appropriately.

As described above, the same effect as described above was achieved by making the number of revolutions of the intermediate transfer belt 11, that is, the time during which the static elimination roller 21 is in contact with and polished, correspond to the environmental condition.

By the way, according to the conventional example, at 32 ° C. and 75% under a high temperature and high humidity environment, 10,000 sheets were printed under the condition that the external additive strontium titanate amount in the toner was 0% (% by weight). In the following number of copies, a fusion streak and a spot were generated when the power was turned on at the start of work. However, due to the relative speed difference increase and the photosensitive drum rotation speed increase (polishing time increase) in this embodiment, both It was confirmed that more than 20,000 sheets were prevented from fusion streaks and spots. At this time, A4 lateral feed, image duty ratio 6%, and one sheet intermittent copy.

Here, according to the environment, the control of the rotational speed or the rotational speed of the intermediate transfer belt 11 during non-image formation is controlled by a control circuit (not shown). As the control transmission system, the conditions detected by the temperature / humidity sensor arranged in the sheet feeding portion of the image forming apparatus used in the present invention (not shown) are converted into signals, which are transmitted to the control circuit arithmetic circuit, and transferred. It is sent to the belt drive motor control circuit to control the rotation of the transfer belt.

In this embodiment, the image forming apparatus of the multiple development batch transfer system has been described, but the same effect can be obtained in the image forming apparatus of the 4-drum tandem hopper system.

[0084]

As is apparent from the above description, according to the present invention, the intermediate transfer member and the discharging unit are driven with a relative speed difference even when the abrasive-less toner is used in consideration of high image quality. Moreover, by applying an AC bias superimposingly for the purpose of improving the effect of removing deposits during static elimination, the occurrence of filming due to long-term use and the deposition of silicon oil during fixing without complicating the structure. Prevent the cleaning failure due to the above, simultaneously secure the cleaning property in the simple transfer member cleaning device and the charge removal property on the transfer member, and prevent the deterioration of the image quality due to the prevention of the reverse rotation of the cleaning blade and the deformation of the transfer member for a long time. It is possible to achieve prevention and high-quality image stable formation, and it is possible to ensure high image quality. Effect that the image deterioration due to failure or the belt conveyance failure image by memory can be prevented.

[Brief description of drawings]

FIG. 1 is a sectional view of a main part of an image forming apparatus according to a first embodiment of the present invention.

2 is a partially enlarged view of the image forming apparatus shown in FIG.

FIG. 3 is an operation sequence diagram of the image forming apparatus according to the first embodiment of the present invention.

FIG. 4 is an operation sequence diagram of the image forming apparatus according to the second embodiment of the present invention.

FIG. 5 is an operation sequence diagram of the image forming apparatus according to the third embodiment of the present invention.

FIG. 6 is an operation sequence diagram of the image forming apparatus according to the fourth embodiment of the present invention.

[Explanation of symbols]

1 photosensitive drum 2 Primary charger 3 Blank exposure section 4a First image forming unit 4b Second image forming unit 4c Third image forming unit 4d Fourth image forming unit 5 Cleaning device 8 Primary transfer bias roller 9 Support roller 10 Opposing roller 11 Intermediate transfer belt 12 Secondary transfer bias roller 14 Fixing means 15 Pre-exposure lamp 16,17 Cleaning blade 18 Transfer material transport path 19 Opposing roller 20 Static elimination roller 21 Grounding material for antistatic roller 100 Image forming apparatus main body P transfer material

Continued front page    F-term (reference) 2H027 DA11 DA14 DA16 DA31 DA39                       DE01 DE07 DE09 EA10 EA15                       EA18 EC06 EC09 ED24 ED26                       EE03 EE04 EF11 JC03 JC16                 2H071 BA03 BA20 BA42 CA01 CA07                       DA09 DA26 DA32 EA18                 2H200 FA01 FA20 GA23 GA47 GA51                       GB33 JC03 JC11 JC17 JC18                       JC19 JC20 LA19 LA20 LA29                       LA38 MC02 MC06 NA06 PA11                       PB14 PB27 PB28 PB35 PB36

Claims (7)

[Claims] 1. An image carrier having a movable surface on which a latent image is formed, an intermediate transfer member for transferring a toner image formed on the image carrier to a sheet material, and the intermediate transfer. A static charge removing means for contacting the intermediate transfer body with an AC bias to remove static electricity from the intermediate transfer body; and an intermediate transfer body driving means for driving the intermediate transfer body. The intermediate transfer body and the static removing means are in contact with each other, In addition, in the image forming apparatus in which the image forming agent does not contain an abrasive, the image forming apparatus has a relative speed difference between the intermediate transfer member and the drive speed of the charge removal. 2. The surface hardness H1 of the static elimination roller, which directly contacts the surface on which the transfer material is loaded, and the surface hardness H2 of the intermediate transfer member.
And H1> H2, and the JIS10 point average roughness of the surface of the charge eliminating roller is R1, and the average roughness of the transfer body surface is R2, the relationship of R1> R2 is satisfied. The image forming apparatus according to claim 1, wherein: 3. At least one of the driving speeds of the intermediate transfer body and the static elimination means when there is a relative speed difference between the driving speed of the intermediate transfer body and the driving speed of the static elimination means, 2. The image forming apparatus according to claim 1, wherein the toner image formed on the image carrier is at a speed higher than the driving speed at which the toner image is transferred onto the sheet material. 4. The static eliminator driving is stopped when there is a relative speed difference between the drive speed of the intermediate transfer member and the drive speed of the static eliminator. Item 4. The image forming apparatus according to any one of Items 1 to 3. 5. A detection unit for detecting at least one of temperature and humidity of the image forming apparatus main body, and based on a detection result of the detection unit, at least one of the intermediate transfer member and the static elimination unit. The image forming apparatus according to claim 1, wherein the driving speed of the image forming apparatus is changed. 6. The driving time of at least one of the intermediate transfer member and the charge eliminating unit is changed based on a detection result of the detecting unit.
The image forming apparatus according to any one of 1 to 5. 7. When there is a relative speed difference between the drive speed of the intermediate transfer member and the drive speed of the static eliminator,
7. The image forming apparatus according to claim 1, wherein the latent image is formed on the image carrier and the toner image is not transferred to the sheet material. .