JP2003131440A - Image forming apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an image forming apparatus in which cleaning property and transfer body destaticization property are secured, and an image quality is consequently prevented from being deteriorated, while avoiding complication of structure. SOLUTION: The representative structure of the image forming apparatus includes a photoreceptor drum 1 which has a movable surface and on which a latent image is formed, an intermediate transfer belt 11 for transferring a toner image formed on the photoreceptor drum 1 to a transfer material P, and a destaticization roller 21 which is brought into contact with the intermediate transfer belt 11 and destaticizes the intermediate transfer belt 11. In the image forming apparatus, the intermediate transfer belt 11 and the destaticization roller 21 are brought into contact with each other. In a surface of at least one of the front surface of the intermediate transfer belt 11, or its rear surface, the apparatus has the relative speed difference in driving speeds between the intermediate transfer belt 11 and the destaticization roller 21. Provided that H1 means surface hardness of the destaticization roller 21 which directly abuts on the surface where the transfer material P is loaded, and H2 means the surface hardness of the intermediate transfer belt 11, a relation of H1>H2 is established. Provided that R1 means surface roughness of JIS 10-point average of the destaticization roller 21, and R2 means the average surface roughness of the intermediate transfer belt 11, the relation of R1>R2 is established.

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, an elastic part such as urethane rubber is formed in a plate shape,
A cleaning blade 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 a small size, and is advantageous in terms of cost, and also has the advantage of being excellent in toner removal performance, and thus is widely used in practice. ing.

Further, in a high-quality color image forming apparatus which requires particularly high speed and high image quality, in order to minimize damage to the transfer body, a simple light pressure type brush cleaner or cleaning is used rather than a cleaning blade. There are some models that have introduced the less type.

Recently, in response to the demand for higher speed, a belt type intermediate body is being used frequently, and the inner surface of the belt (back surface: non-image forming image carrier surface) is contaminated by scattered toner, and Conventionally, the problem of the occurrence of image defects has conventionally been dealt with by disposing a belt back surface cleaning member.

[0008]

[Problems to be Solved by the Invention]

However, in the above-mentioned image forming apparatus, since the cleaning blade is brought into contact with the surface of the photosensitive drum, the residual toner is strongly adhered to the cleaning blade as the image forming apparatus is used for a long period of time, and so-called fill In some cases, the image quality may deteriorate and the image quality thereafter may deteriorate.

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. To prevent this, apply silicone oil to the roller surface.

This silicon oil adheres to the transfer device when the toner image on the second surface is transferred, and adheres to the intermediate transfer body when the image on the next page is formed.

The silicon oil adhering to the surface of the intermediate transfer member is partially transferred to and adheres to the photosensitive drum which is in contact with the intermediate transfer member, and the silicon oil passes through the edge of the cleaning blade due to charging failure due to oil contamination of the intermediate transfer member. As a result, cleaning failure may occur.

Further, in order to achieve high image quality due to the structure provided with the transfer member, the setting of the cleaning mechanism on the transfer member should be as light as possible, simplified, and toner of high transfer efficiency is used. On the premise of this, cleanerless technology is being put to practical use.

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 is unavoidable.

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

The holding of the electric memory by charging is
The residual toner having a charge on the intermediate transfer member, which is a factor that hinders image failure and long-term stabilization of image quality, has a drawback that it is difficult to clean.

Further, in the model using the intermediate transfer member, there is a problem that the 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 keeps increasing, and the friction coefficient between the transfer body and the cleaning member increases with the progress of durability. Especially the wavy transfer belt system,
There are many problems that are difficult to solve, such as color shift due to deformation and machine down due to reversal of cleaning blade.

On the other hand, in recent years, the pursuit of high-quality images has become remarkable, and the reduction in the particle size of the toner, which is the developer, has been increased by the speeding up of the image forming apparatus and the rubbing operation by the cleaning member. As a result, it is a cause of exacerbating the toner scattering in the machine. On the other hand, improvement of the air flow in the machine and electrostatic coagulation by increasing the electrostatic amount of toner have been common solutions.

However, there is a limit to the improvement of the air flow inside the machine. That is, when the suction force is increased, the scattered toner from the developing device and the waste toner from the waste toner box in the cleaning device are sucked out, and the periphery of the photosensitive drum or the intermediate transfer member, especially the belt-shaped intermediate transfer member is sucked. However, there is a problem in that the back surface (non-image forming image bearing member: inside) is contaminated, which easily causes image defects due to transfer charging failure. Particularly, there is a problem that the contamination of the belt system by the scattered toner is deposited and fused on the surface layer of the belt driving roller, which is a belt driving means, and hinders the rotation of the belt itself. Specifically, there are belt slip, skew, and wrinkles.

The present invention has been made in view of the above circumstances, and an image forming apparatus capable of preventing the deterioration of image quality while avoiding the complication of the structure, ensuring the cleaning property and the charge removing property of the transfer body. The purpose is to provide.

[0024]

In order to solve the above problems, a typical structure of an image forming apparatus according to the present invention is an image carrier having a movable surface and on which a latent image is formed, and An intermediate transfer member for transferring the toner image formed on the image carrier to a transfer material, and a discharging unit contacting with the intermediate transfer member and discharging the intermediate transfer member are provided. In an image forming apparatus in which the charge removing means are in contact with each other, at least one of the front surface and the back surface of the intermediate transfer body has a relative speed difference between the driving speed of the intermediate transfer body and the charge removing means, When the surface hardness H1 of the charge eliminating means directly contacting the surface on which the sheet is loaded and the surface hardness H2 of the intermediate transfer body, the relationship of H1> H2 is established, and J of the surface of the charge eliminating means is satisfied.
When the average roughness of IS10 points is R1 and the average roughness of the surface of the intermediate transfer member is R2, the relationship of R1> R2 is established.

[0025]

BEST MODE FOR CARRYING OUT THE INVENTION First Embodiment A first embodiment of the image forming apparatus according to the present invention will be described with reference to the drawings. 1 is a partial configuration diagram of an image forming apparatus according to the present embodiment, FIG. 2 is a partially enlarged view of the image forming apparatus, and FIG. 3 is a diagram showing an operation sequence of the image forming apparatus.

As shown in FIG. 1, the image forming apparatus is a four-color full-color copying machine.
Inside the apparatus main body), four image forming units, that is, the first image forming unit 4a and the second image forming unit 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 the image carrier.
Image forming section 4b, third image forming section 4c, and fourth image forming section 4d.

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. As the photosensitive drum 1, a carrier generation layer (CGL) is formed on the surface of a cylindrical aluminum substrate.
And a photosensitive layer having a carrier transport layer (CTL),
The coating was used so that the thickness of L was 40 μm, and the Rz (10-point average) that was JIS surface roughness (B601) 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 had an outer diameter of 80 mm.

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 portions 4a to 4d,
It is developed as a toner image. As the developer, a two-component developer mainly containing a silicon-based toner and a ferrite-based carrier was used.

The toner image is 0.049, and the linear pressure on the photosensitive drum 1 (a value obtained by dividing the member pressure applied in the thrust direction by the drum thrust direction length) is 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 brought into contact with the transfer portion, which is pressed by N / cm and rotates in the forward direction, the intermediate transfer belt 11 is precharged.
By the action of the electric field formed by the transfer, the photosensitive drum 1 is transferred to the intermediate transfer belt 11 in the form of electrostatic attraction.

Here, P1 = P2> 0, where P1 is the contact pressure of the charge eliminating roller 21 as the charge eliminating means on the intermediate transfer belt 11 during image formation, and P2 is the contact pressure during non-image formation.
Are 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.

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

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

As shown in FIG. 2, in this embodiment, EPDM rubber is used for the base layer 11a constituting the intermediate belt 11, and the base layer 11a is coated with a coating in which PVDF resin is dispersed to coat the surface layer 11b. And

EPDM rubber is used for the base layer constituting the static elimination roller 21, and carbon is dispersed and internally added as a conductive filler to this belt layer to obtain an average surface roughness of hardness 40 degrees (Asker C load 4.9 N). A product having a thickness of 10 μm to 20 μm is used as a surface layer in contact with the intermediate transfer belt 11, and the electric resistance is 1.0 × 10E5 to 1.0 × 10E6Ω or less.

The surface layer of the antistatic roller facing earth member 22 that is opposed to the intermediate transfer belt 11 with the same interposed therebetween is made of the same material so that the electric charge due to the antistatic is used as the earth.
Both rollers had an outer diameter of 16 mm, a thrust length of 306, a contact pressure of the charge eliminating member with respect to the intermediate transfer belt 11 was a total pressure of 3.92 N, and an average surface roughness of 6 um to 10 um was used.

The intermediate transfer belt 11 has 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 driving roller 19 facing the cleaning blade 16 indicated by an arrow B. It is hung so that it can be conveyed and rotated.

As a cleaning means for the intermediate transfer belt 11, a cleaning blade 16 was brought into contact with the intermediate transfer belt 11 in the forward direction with respect to the rotating direction of the intermediate transfer belt 11. 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 10 Ω · c.
AL material of m or less is used as core metal, BIE (butadiene isoprene EPDM) material is used for the surface layer, and electric resistance is 10E.
It was set to 5 to 10E6 Ω · cm or less. The rubber hardness used in JIS-A was 50 ° or more. In addition,
The core metal was grounded. The contact pressure between the drive roller 19 and the charge eliminating roller 21 was 0.49 N / m.

After the transfer of the toner image, 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 portions 4a to 4d are used.
The toner color of the toner image developed by
The toner images of four colors are collectively transferred onto the intermediate transfer drum 11 by the primary transfer bias roller 8. Then, the transfer material P is conveyed to the secondary transfer bias roller 12 so as to match the timing with the toner composite image on the intermediate transfer belt 11, and the toner composite image is collectively transferred to the transfer material P there. The transfer material P to which the toner composite image has been transferred passes through the transfer material conveying path 18 and the toner image is fixed by the fixing means 14 to obtain a copy image.

At this time, the surface of the fixing roller 14a of the fixing means 14 is coated with, for example, silicone oil as a release agent so that the toner on the transfer material P does not adhere to the surface of the fixing roller.

The transfer material P having a toner image formed on the front surface (first surface) passes over a flapper (not shown) and is discharged onto a discharge 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 surface is guided to the lower sheet re-feeding unit by the switching of the flapper without being discharged to the discharge tray.

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

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

The operation of the first embodiment of the image forming apparatus according to the present invention described above will now be described.

As shown in FIG. 3, in order to generate a rotational speed difference between the intermediate transfer belt 11 and the charge eliminating roller 21, which is a characteristic part of the present invention, the rotation of the intermediate transfer belt 11 during non-image formation. Process speed from 120mm / sec to 160mm
The speed was increased to / sec.

During the idling operation, a charge of minus 3000 V was applied to the charge eliminating roller 21. Here, the static elimination roller 21 is
The intermediate transfer belt 11 is rotated and abutted in the forward direction.

Due to the relative speed difference generated, a frictional force is generated between the intermediate transfer belt 11 and the static elimination roller 21, and the intermediate transfer belt 11 and the static elimination roller 21 operate to grind each other, and the static elimination roller 21 Vibration occurs due to the applied voltage of 21. As a result, it is possible to remove foreign matter such as shavings and dust of the residual toner belt accumulated on the surface of the intermediate transfer belt 11 and the surface of the charge eliminating roller 21 due to the accumulation of the number of times of image formation, thereby achieving high quality and stable image formation. I was able to.

In this embodiment, the contact pressure of the cleaning blade 16 contacting the intermediate transfer belt 11 is set to 0.196 N / c.
m, and an endurance test was carried out in an environmental test room at 75 ° C. at 32 ° C. where the environmental conditions are high temperature and high humidity. In this experiment, an image with an image ratio of about 25% was set as the endurance mode.
The evaluation was performed by continuous copying with 4 sizes of transverse feed.

As a result, in the past, at the time of 30,000 sheets, image defective toner fusion spots, streaks and oil streak cleaning defects, which are considered to be caused by charging products, were generated.
It has been confirmed that the good condition is maintained even after the passage of 350,000 sheets.

Conventionally, at the time of 100,000 sheets, slips due to adhered rubbing stains, which are considered to be scattered toner inside the machine, have been generated on the inner surface of the belt, but even after 150,000 sheets have passed, a good condition can be maintained. did it.

Further, within 50,000 sheets, the transfer cleaning blade 16 was turned up due to the increase of the friction coefficient due to the surface roughness reduction of the transfer belt surface portion, but even with the number of blade replacement of 75,000 sheets. It was confirmed that good rubbing property was maintained.

As described above, the intermediate transfer belt 11 and the discharging roller 21 are driven with a relative speed difference during the non-image forming operation or the like, so that the intermediate transfer can be performed without affecting the image forming operation. Due to the friction coefficient of the belt 11 and the static elimination roller 21, these mutually grind each other, and it is possible to effectively remove the dust and the like remaining on the intermediate transfer belt 11 and the static elimination roller 21. In addition, it is possible to form an image with high stability.

When the intermediate transfer belt 11 and the discharging roller 21 are driven with a relative speed difference, the photosensitive drum 1
Even when the intermediate transfer belt 11 and the charge eliminating roller 21 rub against each other, the image forming operation is affected because the latent image is formed on the transfer material and the toner image is transferred to the transfer material. It is possible to maintain the image quality.

Second Embodiment Next, a second embodiment of the image forming apparatus according to the present invention will be described with reference to the drawings. FIG. 4 is a diagram showing an operation sequence of the image forming apparatus according to this embodiment. The same parts as those of the first embodiment will be designated by the same reference numerals and the description thereof will be omitted.

In the present embodiment, the constant speed difference, which is the main feature of the above-described first embodiment, is avoided at a certain number of copy sheets, avoiding to always input the sequence as in the first embodiment during non-image formation. Utilizing the polishing ability improvement that was used,
We aim to achieve high image quality and high stability.

However, in this operation sequence, the number of times of polishing is reduced as compared with the first embodiment, and this reduction must be covered by another means. Therefore, as shown in FIG. 4, in the present embodiment, the process speed of one rotation of the intermediate transfer belt 11 at the time of non-image formation is 200 mm compared to 120 mm / sec at the time of image formation.
/ Sec (160 mm / sec in the first embodiment)
At the same time, the rotation process speed of the static elimination roller 21 is also 12
From 0 mm / sec to 150 mm / sec (120 mm / sec in the above first embodiment), the intermediate transfer member 11
It was decided to increase the number of times of polishing between the charge-removing roller 21 and the charge-removing roller 21.

This is particularly effective in an image forming apparatus that does not have a double-sided continuous copy version. In the executed sequence, the sequence is input once every 5,000 copies, and the number of polishing is increased unnecessarily. By eliminating the above, the life of the intermediate transfer belt 11 and the static elimination roller 21 can be extended.

As the experimental evaluation, the same evaluation mode as in the first embodiment described above was used. As a result, in the conventional technique, image blurring toner fusion stripes and spots due to poor charging occurred at 20,000 sheets or less at 32 ° C. and 75% under an environment of high temperature and high humidity, but in the present embodiment, Four
It was confirmed that the cleaning ability was maintained up to 10,000 sheets, and that the transfer cleaning blade 16 also maintained good rubbing ability up to the replacement number of 75,000 sheets.

As described above, at least one of the driving speeds of the intermediate transfer belt 11 and the discharging roller 21 when the intermediate transfer belt 11 and the discharging roller 21 are driven with a relative speed difference, Since the speed is higher than the driving speed at the time of transferring the toner image formed on No. 1 to the transfer material, the polishing property and the cleaning property can be further improved.

Further, since the intermediate transfer belt 11 and the discharging roller 21 are driven with a relative speed difference once for every 5,000 copies, they are not always driven with a relative speed difference. Therefore, the intermediate transfer belt 11 and the static elimination roller
It is possible to reduce the burden on each other and 21 and to extend the service life.

Third Embodiment Next, a third embodiment of the image forming apparatus according to the present invention will be described with reference to the drawings. 5 and 6 are diagrams showing an operation sequence of the image forming apparatus according to the present embodiment. The same parts as those of the first embodiment will be designated by the same reference numerals and the description thereof will be omitted.

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

As shown in FIG. 5, this embodiment was applied to a high speed copying machine having a high process speed of 160 mm / sec. A drum with a diameter of 180 mm was used in response to higher speeds.

In order to cover the decrease in the number of polishing,
In the present embodiment, the process speed of one rotation of the intermediate transfer belt 11 during non-image formation is 120 m during image formation.
180 mm / sec with respect to m / sec (160 mm / sec in the first embodiment, 200 mm / sec in the second embodiment)
sec), and at the same time, the rotation process speed of the static elimination roller 21 is also changed from 120 mm / sec to 0 mm / sec (120 mm / sec in the first embodiment, 150 mm / sec in the third embodiment), and stopped. It was decided to increase the number of times of polishing between the transfer body 11 and the discharging roller 21.

As the experimental evaluation, the same evaluation mode as in the first embodiment described above was used. The sequence is input once for every 5,000 copies, and the life of the intermediate transfer belt 11 and the static elimination roller 21 is extended by not increasing the number of polishing times unnecessarily. As a result, in the conventional technique, filming occurred in 5,000 copies, but in the present embodiment, it is possible to remove the filming adhered more firmly than in the second embodiment. It was possible to achieve 20,000 sheets.

Further, as shown in FIG. 6, as a form in which the completely same effect can be confirmed, the intermediate transfer belt 11 is stopped at the time of non-image formation, and the rotation process speed of the charge eliminating roller 21 is set to 180 mm / sec. Even in this state, it is possible to obtain substantially the same effect as described above.

As described above, when the intermediate transfer belt 11 and the discharging roller 21 are driven with a relative speed difference, the driving of the intermediate transfer belt 11 is stopped. Therefore, the intermediate transfer belt 11 and the discharging roller 21 are stopped. The relative speed difference between the two becomes larger and the polishing property and cleaning property can be further improved.

Further, when the intermediate transfer belt 11 and the discharging roller 21 are driven with a relative speed difference, the discharging roller is
Since the drive of 21 is stopped, the intermediate transfer belt 11
The relative speed difference between the charge-removing roller 21 and the charge-removing roller 21 is increased, and the polishing property and the cleaning property can be further improved.

[Fourth Embodiment] Next, a fourth embodiment of the image forming apparatus according to the present invention will be described with reference to the drawings. 7 to 9 are diagrams showing an operation sequence of the image forming apparatus according to the present embodiment. The same parts as those of the first embodiment will be designated by the same reference numerals and the description thereof will be omitted.

In the present embodiment, in order to have a structure in which filming or the like is less likely to occur, the image forming apparatus is designed with a process design in which the external additive component in the toner is reduced.
The main purpose is to suppress the occurrence of image defects such as spots.

Component of external additive in toner (especially abrasive)
It is advantageous to reduce damage to the photoconductor (durability, rubbing scratches, etc.), delay the occurrence of image defects such as vertical streaks due to scratches, and extend the life of the photoconductor.
On the other hand, the abrasion amount of the photoconductor is reduced, and the removal ability of the fusion products that inhibit the charging ability of the photoconductor and the transfer body is deteriorated, and abnormal images such as fusion stripes and spots are generated on the image. I will let you.

In the present embodiment, especially in a high temperature and high humidity environment, the sequence of increasing the polishing force between the intermediate transfer belt 11 and the charge eliminating roller 21 seen in the first embodiment described above is incorporated, and the high temperature and high humidity environment is adopted. In order to improve the polishing power more than the other sequences, we introduced a sequence that changes the polishing power in conjunction with the environmental conditions in the equipment.

On the contrary, when the polishing force is not so required, 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.

As environmental conditions, I (internal temperature 20 ° C. to 3 ° C.)
Below 0 ° C, humidity 10% to less than 60%), II (internal temperature 30 ° C to 45 ° C, humidity 60% to less than 80%), III (internal temperature 45 ° C or more, humidity 80% or more) Split.

As shown in FIG. 7, under the environmental condition of category I, in order to generate a rotational speed difference between the intermediate transfer belt 11 and the discharging roller 21, the rotation of the intermediate transfer belt 11 during non-image formation. Process speed from 160 mm / sec to 170 m
The speed was increased to m / sec.

As shown in FIG. 8, under the environmental conditions of Category II, the rotation process speed of the intermediate transfer belt 11 was increased from 160 mm / sec to 180 mm / sec during non-image formation.

As shown in FIG. 9, under the environmental condition of Category III, the rotation process speed of the intermediate transfer belt 11 was increased from 160 mm / sec to 190 mm / sec during non-image formation.

Corresponding to the above environment, the control of 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, which is a detection means arranged in the sheet feeding unit of the image forming apparatus used in the present invention (not shown), are converted into signals and converted into the above-mentioned control circuit arithmetic circuit. It is transmitted and sent to the transfer belt drive motor control circuit to control the rotation of the transfer belt.

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 has become possible to create an efficient high-quality stabilization sequence.

Furthermore, the surface of the transfer belt is moderately roughened by the rotary polishing, and it is possible to prevent the transfer cleaning blade 16 from being turned upside down in a high temperature and high humidity environment due to the speedup of the process, and to eliminate expected adverse effects. It was possible to achieve 750,000 blades, which is the guideline for blade 16 replacement.

Depending on the environmental classification in the image forming apparatus, the rotation speed may be increased in addition to increasing the rotation process speed of the intermediate transfer belt 11 during non-image formation.

For example, in section I, the rotation speed of the intermediate transfer belt is set to 3 times. In Category II, the rotation speed of the intermediate transfer belt was set to four. In Category III,
The number of rotations 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.

From the above, the number of rotations of the intermediate transfer belt 11,
In other words, the same effect as described above can be obtained by making the time for contact polishing with the static elimination roller 21 correspond to the environmental condition.

As the experimental evaluation, the same evaluation mode as in the first embodiment described above was used. As a result, according to the conventional example, at 32 ° C. and 75% under a high temperature and high humidity environment, the external additive strontium titanate amount in the toner was 0.5% under the condition of 0.2% (weight%). With less than 10,000 copies,
When the power supply was turned on at the start of work, fusion streaks and spots were generated, but both were 2 due to the relative speed difference increase and the photosensitive drum rotation speed increase (polishing time increase) in the present embodiment.
Over 10,000 sheets were able to prevent fusion streaks and spots.

As described above, since at least one of the temperature and humidity of the image forming apparatus main body is detected, the driving speed is changed according to the environment inside the apparatus, and the driving operation is performed as necessary. Therefore, it is possible to extend the life of the device while maintaining the polishing property and the cleaning property.

Further, the drive time of at least one of the intermediate transfer belt 11 and the charge eliminating roller 21 may be changed based on the result of the temperature / humidity sensor that detects at least one of the temperature and humidity of the image forming apparatus main body. Therefore, the driving time is changed according to the environment inside the apparatus, and the driving operation can be performed as needed, and the life of the apparatus can be extended while maintaining the polishing property and the cleaning property. .

[0091]

As is apparent from the above description, according to the present invention, since the intermediate transfer member and the discharging means are driven with a relative speed difference, the structure is not complicated and
Prevents defective cleaning due to filming due to long-term use and adhesion of silicone oil at the time of fixing, simultaneously secures the cleaning property of a simple transfer member cleaning device and the charge removal property on the transfer member, and for a long time It is possible to prevent deterioration of image quality by preventing reversal of the cleaning blade and deformation of the transfer body, and to achieve stable image formation with high image quality. It is possible to provide an image forming apparatus that can prevent image deterioration due to poor belt conveyance that is caused by contamination.

[Brief description of drawings]

FIG. 1 is a partial configuration diagram of an image forming apparatus according to a first embodiment.

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

FIG. 3 is a diagram showing an operation sequence of the image forming apparatus.

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

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

FIG. 6 is a diagram showing an operation sequence of the image forming apparatus.

FIG. 7 is a diagram showing an operation sequence of the image forming apparatus according to the fourth embodiment.

FIG. 8 is a diagram showing an operation sequence of the image forming apparatus.

FIG. 9 is a diagram showing an operation sequence of the image forming apparatus.

[Explanation of symbols]

P ... Transfer material 1 ... Photosensitive drum 4a ... 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 14a ... Fusing roller 15… Pre-exposure lamp 16… Cleaning blade 17… Cleaning blade 18 ... Transfer material transport path 19… Drive roller 21… Static elimination roller 22… Grounding member facing the static elimination roller 100… Image forming device body

Claims (10)

[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 transfer material, and the intermediate transfer member. An image forming apparatus in which the intermediate transfer member and the charge removing unit are in contact with each other, and at least one of the front surface and the back surface of the intermediate transfer member. In the above, there is a relative speed difference between the intermediate transfer body and the drive speed of the charge eliminating means, and the surface hardness H1 of the charge eliminating means and the surface hardness H2 of the intermediate transfer body that directly contact the surface on which the transfer material is loaded.
The relation of H1> H2 is established, and the relation of R1> R2 is established when the average roughness of JIS 10 points on the surface of the static eliminator is R1 and the average roughness of the surface of the intermediate transfer member is R2. Image forming apparatus. 2. The driving speed of the intermediate transfer member and the driving speed of the charge eliminating means except when the latent image is formed on the image carrier and when the toner image is transferred to the transfer material. The image forming apparatus according to claim 1, wherein the image forming apparatus has a relative speed difference between the image forming apparatus and the image forming apparatus. 3. When the driving speed of the intermediate transfer member and the driving speed of the charge eliminating unit have a relative speed difference, it is performed every time a predetermined number of images are formed or every time a predetermined time elapses. 2. The image forming apparatus according to item 2. 4. When there is a relative speed difference between the drive speed of the intermediate transfer member and the drive speed of the charge eliminating unit, at least one of the drive speeds of the intermediate transfer member and the charge eliminating unit has no relative speed difference. The image forming apparatus according to claim 1, wherein the image forming apparatus is faster than each driving speed. 5. The driving of the intermediate transfer body is stopped when the driving speed of the intermediate transfer body and the driving speed of the static eliminator have a relative speed difference. The image forming apparatus according to any one of 1. 6. When the drive speed of the intermediate transfer member and the drive speed of the charge eliminating unit have a relative speed difference, the drive speed of the charge eliminating unit is lower than the drive speed of the charge eliminating unit when there is no relative speed difference. The image forming apparatus according to claim 5, wherein the image forming apparatus is also fast. 7. The discharging device is stopped when the driving speed of the intermediate transfer member and the driving speed of the discharging unit have a relative speed difference. The image forming apparatus according to any one of claims. 8. The driving of the intermediate transfer body when the driving speed of the intermediate transfer body and the driving speed of the charge removing unit have a relative speed difference, and when the driving speed of the intermediate transfer body has no relative speed difference. The image forming apparatus according to claim 7, wherein the image forming apparatus is faster than the speed. 9. A detection unit that detects at least one of temperature and humidity of the image forming apparatus main body, and changes a drive speed of at least one of the intermediate transfer member and the charge eliminating unit based on a detection result of the detection unit. The image forming apparatus according to claim 1, further comprising: 10. A detection unit that detects at least one of temperature and humidity of the image forming apparatus main body, and changes drive time of at least one of the intermediate transfer member and the charge eliminating unit based on a detection result of the detection unit. The image forming apparatus according to claim 1, further comprising: