JP2000039822A - Image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an image forming device capable of realizing reduction of ozone evolution quantities, cost reduction, and miniaturization, and moreover suppression of the noise generation at the working time. SOLUTION: This image forming device has a conductive cleaning member 7 of a single body structure, containing conductive material, and in which distribution density of the conductive material in the vicinity of a section held in contact with a body to come into contact such as a transfer charger 5 is thinner than another section or is absent. This conductive cleaning member 7 is for removing and flattening the toner on a photoreceptor 1, and moreover characterized by a fact that impact resistance in the contact part vicinity with the body to come into contact is larger than another section.

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 employing an electrophotographic process, such as a copying machine and a printer.

[0002]

2. Description of the Related Art Conventionally, in an image forming apparatus adopting an electrophotographic process, a member called a cleaning blade is brought into contact with a member such as a cleaning blade to clean an adhering matter such as toner adhering to a photoreceptor or the like. Is widely known.

[0003] The cleaning blade removes attached matter such as toner at a photosensitive member contact portion (hereinafter, referred to as an edge portion). When such a cleaning blade is brought into contact with an elastomer, there is a problem that vibration of the blade-like elastomer is transmitted to a contacted body such as a photoreceptor and noise is amplified.

That is, the edge of the cleaning blade is retracted in a minute range with the movement of the contacted member such as the photosensitive member. When the edge of the cleaning blade exceeds the limit, the edge jumps from the photosensitive member and returns to the original position. By repeating a movement called "and slip", toner is removed from the photoconductor. At that time, an unpleasant sound is generated from the cleaning blade.

[0005] Such a problem is the same as in the case where the blade-shaped member is brought into contact with the photoreceptor to remove and charge the photoreceptor, and the vibration component is further increased by the AC component applied to the blade.

However, if the rebound resilience is generally reduced in order to prevent the occurrence of stick and slip, the hardness and Young's modulus of the cleaning blade become large and hard, so that the contact nip with the photoreceptor becomes small. , It was difficult to ensure cleaning performance. In particular, when a small-diameter photosensitive member is used, the mounting accuracy of the cleaning blade is required.

[0007] In addition to the above problem, the voltage applied to the photoreceptor when the photoreceptor has a defect such as a flaw is leaked to the photoreceptor because the blade is a conductive portion. There was such a problem. And it was difficult to control the resistance sensitively depending on the amount of the conductive agent added to the substrate. Furthermore, a conductive member having a multilayer structure such as a roller coated with a tube has a complicated structure and is expensive.

[0008] Further, a conductive member such as a blade having an insulating layer applied or adhered to a conductive base material has a risk that the conductive agent may be peeled or peeled off when the insulating layer is worn. It was more expensive than a single structure.

[0009]

As described above, in an image forming apparatus employing a conventional electrophotographic process,
There has been a problem that vibration noise is generated due to a blade or the like that comes into contact with the photoconductor. Further, particularly when the conductive member is in contact with the photoconductor, there is a problem that the voltage applied to the conductive member leaks to the photoconductor, and the characteristics and configuration of the conductive member should be improved. A point was left.

[0010] However, it is very difficult to control the resistance of the conductive member, and at present it has not been realized. SUMMARY An advantage of some aspects of the invention is to provide a contact member and an image forming apparatus that do not generate vibration noise. In addition, when the contact member is a conductive member, the contact member can easily control the resistance and can prevent the occurrence of a leak to a photoreceptor or the like, and an image forming apparatus including the contact member. To provide.

[0011]

In order to achieve the above object, according to the present invention, a charging means for charging an image carrier, a latent image forming means for forming an electrostatic latent image on the image carrier, Developing means for supplying a developer to the electrostatic latent image to perform development, conveying means for conveying the material to be transferred, and transfer means for transferring the developer image formed by the developing means onto the material to be transferred, A fixing unit configured to fix the developer image on the material to which the transfer is performed by the transfer unit; and a member including a base material containing powder, the image carrier, the transfer unit, and the conveyance unit. And a contact member that contacts any one of the transfer unit and the fixing unit, and has a distribution density of the powder in the contact portion smaller than that in the other portion.

[0012]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a configuration diagram of an image forming apparatus according to a first embodiment of the present invention. In FIG. 1, a negatively chargeable OPC (organic photoreceptor) or the like is employed as the photoreceptor drum 1. This negatively charged OPC
Has the property that it can be neutralized by light for negative charges but cannot be neutralized by light for positive charges (charges of opposite polarity).

Here, the electrophotographic process will be briefly described. With the start of the operation of the photoconductor, the charging charger 2 operates to uniformly charge the surface of the photoconductor negatively. Next, the photosensitive member is exposed by a light source having a wavelength matching the sensitivity of the photosensitive member to form a latent image on the photosensitive member. Here, the laser 3 is employed as a light source.

Next, the developing unit 4 develops toner on the exposed portion of the photoreceptor with respect to the latent image on the photoreceptor. Here, the developing device 4 shows the case of two-component development. This is a reversal development for developing the toner on the exposed portion, and uses a negatively charged toner. Next, the transfer charger 5 applies a charge (positive charge in this example) of reverse polarity to the toner on the back of the sheet 6 to transfer the toner. Next, while the transfer residual toner is dropped by the conductive cleaning member 7, unnecessary positive charges given to the photoreceptor in the transfer unit are removed. This static elimination function will be described later.

The conductive cleaning member 7 can charge the photosensitive member to a negative polarity by controlling the voltage. Then
The negative charge on the photoconductor is erased by the photo-static eliminator 8, a process for equalizing the surface potential on the photoconductor is provided before the charging process, and the process proceeds to the charging process. The light neutralizer 8 may be any light source having a wavelength that matches the sensitivity of the photoconductor, and an appropriate lamp may be selected. Image formation is performed by repeating the above cycle.

The charging device and the transferring device used in the description have the same function even in the case of a roller-type contact type, and the exposure unit may be an LED array or the like in addition to the laser. Of course, it is possible.

Here, the cleaning member 7 will be described. In producing the cleaning member 7, carbon black (Toka Black # 5500: manufactured by Tokai Carbon Co., Ltd.) is used to heat and dissolve the polyester polyol and reduce the rebound resilience of the cleaning blade.
And carbon black dispersant Disparon DA-703-
50 (manufactured by Kusumoto Kasei Co., Ltd.) was dispersed therein, and 1,4-diphenylmethanediol was reacted with the dispersion to prepare a prepolymer. After mixing 1,4-butanediol and trimethylolpropane, the mixture was poured into a centrifugal molding drum (described later) shown in FIG. 3 and cured by heating to form a rubber. It was cut to a predetermined size and bonded to a metal holder as shown in FIG. 2 to obtain a cleaning blade. The reason for the production in this manner is based on the following reasons. If carbon black is not mixed in the above-described preparation process, the rubber of the cleaning blade has a rebound resilience of 47% and a hardness of 67 °.
(JISA), Young's modulus was 55 kg / cm ² . When carbon is mixed, rebound resilience 35%, hardness 68 °
(JISA), Young's modulus was 54 kg / cm ² , and electric resistance was 5 × 10 ⁷ Ω / cm. Mixing carbon reduces the rebound resilience and is effective in preventing noise, but hardly changes the hardness or Young's modulus affecting cleaning performance (the above values conform to JIS K630).

That is, it is understood that the separated carbon of the cleaning member 7 changes the rebound resilience.
Therefore, a sample was prepared in which carbon black (Toker Black # 5500) was added to the material of the cleaning blade and the rebound resilience of the cleaning blade was adjusted by varying the content of carbon black.

In manufacturing, the material of the cleaning blade is charged into a rotary drum of a centrifugal molding machine shown in FIG. 3, and the drum is formed while rotating at a predetermined rotation speed. The centrifugal molding machine has a cylinder 77 that is driven to rotate by the motor 7, and the material is charged into the cylinder 77, and the material is molded while being heated to a constant temperature.

In this centrifugal molding machine, the drum is rotated to accelerate the movement of the material having a large true density or specific gravity to the drum mold surface side by centrifugal force. If the true density or specific gravity of the content is greater than the specific gravity of the base material of the blade, the distribution density of the content of the material of the cleaning blade increases toward the drum mold surface side, and the distribution density increases on the air surface side. Small enough or absent.

When the sample was sliced thinly and confirmed with a microscope, it was confirmed that carbon black was not distributed on the air surface side. FIG. 4 shows the results of examining the hardness, Young's modulus, and the like of the sample thus prepared. The electric resistance value is measured at the time of the rubber sheet before being molded into the cleaning blade, and indicates the volume resistance 30 seconds after applying a voltage of 100V.

It can be said from FIG. 4 that carbon black does not exist on the air surface side of the cleaning blade, and although it is expected that the rebound resilience is high,
This means that in portions where the distribution density of carbon black is high, the rebound resilience is low, so that the rebound resilience of the entire cleaning blade is reduced.

These samples were brought into contact with the photoreceptor with a force in which carbon black was not dispersed, and the peripheral speed of
The occurrence of unpleasant noise was confirmed using a 4 mm / s reversal developing printer.

When the occurrence of unpleasant noise due to stick-and-slip was confirmed without applying a bias voltage to the cleaning blade, the noise often occurred immediately after the start of rotation of the photosensitive member and immediately before the stop. .
Confirmed in 1 and 2 samples. Therefore, the rebound resilience 4
It is preferably at most 2%.

Further, a DC voltage of -600 was applied to the sample.
When V, an AC voltage of 400 Hz and 1.5 kVp-p were applied, the surface potential of the photoreceptor was a potential close to the DC component of the applied voltage in each of Nos. 1 to 5.

When a DC component of -600 V and an AC voltage of 1.5 kVp-p are superimposed and applied to the above sample, unpleasant vibration sound is more likely to occur as the frequency increases.
No. at a frequency of 00 Hz. 60 for 1,2,3 samples
Sound having a frequency of 1/2 or 1.2 times of 0 Hz was mainly confirmed. At 400 Hz, no. Vibration noise was confirmed in samples 1 and 2. Therefore, the preferred frequency range 100 to 6
Vibration noise can be prevented from occurring at 00 Hz when the rebound resilience is 40% or less.

As a comparative sample, a cleaning blade was prepared in which the content (carbon black) was distributed also on the mold surface side by adjusting the molding temperature by setting the base material to polyurethane with a thickness of 1.8 mm. That is, the carbon black is also distributed near the edge. As described above, the vibration sound due to the AC voltage is confirmed because the rebound resilience 40
%. Missing carbon black was found at the edge along with the abrasion.

From the above, it can be said that the base material of the cleaning blade contains particles or powder insoluble in the base material and that the content is not distributed near the edge of the cleaning blade. By making the distribution density in the vicinity smaller than that in other parts, the cleaning performance for cleaning the adhered matter such as toner is secured, and unpleasant noise generated by the cleaning blade due to the stick-and-slip or AC component of the applied voltage Can be reduced.

That is, by including the inclusions in the base material, the hardness and the Young's modulus do not increase, so that the nip with the contacted member such as the photosensitive member can be secured. Further, it can be said that although the volume resistivity values of the samples shown in FIG. 15 and the results obtained when a voltage was applied to these samples were used, although the dispersibility of carbon black was biased, The volume resistance value can stably show a desired value.

That is, it becomes clear that the electric resistance of the conductive member can be controlled by the thickness of the portion where the distribution density of the conductive agent is small, regardless of the electric resistance of the portion where the distribution density of the conductive agent is large. A conductive member having the following electric resistance can be easily prepared.

The portion where the distribution density of the conductive agent is small or absent is a portion where the electrical resistance is sufficiently high (for example, three digits or more in volume resistance) with respect to the portion where the distribution density of the conductive agent is large. Is governed by the electric resistance of the portion where the distribution density of the conductive agent is small. In a conventional conductive member, it is difficult to control the electric resistance because the electric resistance is sensitively affected by the amount of the conductive agent contained in the base material.

On the other hand, when the distribution density of the conductive agent is controlled, the electric resistance of the conductive member is hardly affected by the electric resistance of the portion where the distribution density of the conductive agent is large. It does not need to be strict and is easy to control.

Based on these results, the cleaning member 7 shown in FIG. 1 contains carbon black as an insoluble substance in the base material, and imparts a bias to the distribution density of the carbon black in the base material. The portion where the distribution density of the carbon black is low or absent is brought into contact with the photosensitive member. According to such a cleaning portion, as described above, the following effects are obtained in addition to the effects that the vibration resistance is excellent, the manufacturing thereof is easy, and a stable electric resistance is obtained.

That is, the conductive member employed in the prior art has an insulating layer added to a conductive material. That is, for example, a roller coated with a tube or the like of an insulating layer, or a blade applied or attached to the insulating layer. However, coating, applying, or attaching the insulating layer has a problem that the structure of the conductive member is complicated and expensive, and the insulating layer is peeled off when worn.

On the other hand, in the conductive member employed in the present invention, since the distribution density of the conductive agent is small or the non-existent portion comes in contact with the charged member such as the photosensitive member, the inherent friction of the insulating base material is reduced. Durability can be brought out. Furthermore,
With the abrasion of the conductive member due to contact with the member to be charged, it is possible to prevent the conductive agent from dropping and damaging the member to be charged. In addition, since it is a single unit structure, the structure is simple and inexpensive, and problems such as peeling can be prevented.

The material of the cleaning blade is made of polyurethane, silicon, or other rubber material (CR, EPDM, N
BR ...). As a flexible material, P
A, PET, PI, polyester and other organic materials. Many rubber materials contain a plasticizer, and if left in contact with a contacted body, there is a risk of causing plasticizer contamination. Therefore, when the object to be contacted is a photoreceptor, polyurethane or silicon is preferred. However, polyurethane is also preferable, since silicon also has a risk of exuding low molecular oligomers for removal.

The material to be included in the cleaning blade may be an insulator such as glass beads or powdered glass, or a conductive material such as metal particles or powder such as carbon black or lead.

[0038] Carbon black is relatively inexpensive, is easy to take a three-dimensional structure, and can exhibit conductivity in a relatively small amount than metal powder. Furthermore, carbon black has an advantage that conductivity is hardly affected by temperature and humidity. In addition, carbon black includes, for example, Ketjen Black (manufactured by Lion Corporation) and Toka Black # 5500 (manufactured by Tokai Carbon Corporation)
Etc. can be adopted, but it is a matter of course that the present invention is not limited to this.

Here, the above-mentioned carbon black and metal powder exhibit conductivity due to direct contact between fillers.
It is necessary to contain a relatively large amount, and there is a possibility that the physical properties of the base material may be reduced. On the other hand, the ionic conductive agent has an advantage that it can exhibit conductivity with a small amount of addition, and does not deteriorate the physical properties of the base material containing the conductive agent. Therefore, if the conductivity of carbon black or metal powder alone is insufficient, an ionic conductive agent can be used supplementarily.

The ionic conductive agent is not particularly limited, and for example, lithium perchlorate or the like can be used. Further, a carbon black dispersant may be used in addition to the ionic conductive agent. Examples of the carbon black dispersant include Dispalon DA-703-50 (trade name:
Kusumoto Kaseisha).

The ionic conductive agent and the carbon black dispersant may be used alone or in combination. When using both the carbon black and the ionic conductive agent, or carbon black conductive agent, than when using the carbon black alone,
It is possible to exhibit conductivity with a small amount, not to deteriorate the physical properties of the base material, and to have a property that conductivity is hardly affected by temperature and humidity, which is an advantage of carbon black. Therefore, it is preferable that carbon black alone express conductivity, or that both are used in combination.

At this time, it is preferable that the inclusions have a higher true density or specific gravity than the base material. If the true density or specific gravity is higher than the specific gravity of the base material, it will settle even in static molding. However, when the viscosity of the base material is large, when the specific surface area of the content is large, or when the curing speed of the base material is faster than the sedimentation speed of the content, the sedimentation of the content does not proceed, and A part with a sufficiently low distribution density cannot be obtained. The true density here is not the apparent density of particles having large irregularities such as carbon black in the apparent volume but the density in the volume when all the gaps are eliminated.

As described above, a centrifugal molding apparatus as shown in FIG. 14 may be used for the manufacturing apparatus. At this time, the air surface side is used as an edge to contact a contacted object such as a photoreceptor. Make contact. The material surface of the cleaning blade on the drum mold surface side picks up irregularities on the drum mold surface, whereas the drum air surface side has no irregularities, and it is preferable because the contact with the contacted body is ensured. If the cleaning blade material is cut along the centrifugal direction after the rotation of the drum is stopped, a cleaning blade having a uniform thickness can be obtained.

Further, the thickness of the cleaning blade can be controlled by the amount of the material charged into the drum. For example, when the content is carbon black (Toka Black # 5500), the specific gravity is 1.8, whereas when the base material is silicon, the specific gravity is 1.6 to 2.
1. In the case of fluororubber, the specific gravity is 1.85, which is higher than the true density of carbon black, and creates a part where the distribution density of the inclusions is sufficiently low or no longer exists on the air side by centrifugal molding. Can not.

Urethane has a slightly different composition, but has a specific gravity of 1.2 to 1.3. If the content is carbon black, the distribution density of the content on the air surface side by centrifugal molding is sufficiently small or does not exist. Is easy to produce.

An example of the function of the cleaning member 7 for smoothing or removing the charge on the photosensitive member will be described below. First, as described above, in the cleaning member 7 which comes into contact with the photoreceptor after transfer, as shown in FIG. 5, when the cleaning member 7 is electrically floated and brought into contact with the photoreceptor, electric charges are locally accumulated on the surface of the photoreceptor. When there is a part where the mounting state is extremely different from that of the surroundings, the conductive member works so that the state where the electric charge is mounted becomes familiar with the surroundings, and the electric charge is smoothed.

That is, for example, when the transfer of the positive polarity is excessive in the reversal development in which the primary charge of the negative polarity is performed, the charge of the positive polarity is placed on the surface of the photoreceptor corresponding to the outside of the transfer material, and the charge is applied to the inside of the transfer material. A negative polarity charge is placed on the surface of the photoconductor, and a potential difference is formed on the surface of the photoconductor corresponding to the end of the transfer material.

The portion on which the above-mentioned positive polarity charge is applied cannot rise to a desired potential at the time of the next primary charging, causing unnecessary toner to adhere to the photosensitive member, fogging or an intermediate image on the image. Density unevenness occurs in the tone. By bringing an electrically floating conductive member into contact with the photoreceptor, the charge is smoothed at the portion where the positive polarity charge is placed and the portion where the negative polarity charge is placed, and unnecessary toner is placed on the photoreceptor. Can be prevented from adhering and fogging on the image.

On the other hand, as shown in FIG. 6, the conductive member employed in the image forming apparatus of this embodiment is electrically
When the photoconductor is brought into contact with the photoconductor D, the electric charge on the photoconductor acts in the direction of moving in the GND direction, that is, the electric charge is removed, the electric charge is smoothed, and the surface potential of the photoconductor approaches 0V. That is, as described above, when positive polarity charge is applied to the photoreceptor by transfer during reversal development in which negative polarity primary charging is performed, unnecessary toner adheres to the photoreceptor and the image is fogged. Can be eased.

Further, as shown in FIG. 7, when a voltage applying means (= high-voltage transformer) is connected to the conductive member employed in the image forming apparatus of the present embodiment and brought into contact with the photoreceptor, the above-described method is employed. This makes it possible to more reliably remove the charge on the photoconductor, thereby preventing unnecessary toner from adhering to the photoconductor and fogging on the image.

As described above, the function of smoothing or removing the charge on the photosensitive member by the conductive member is performed by applying a voltage,
It is effective in the order of connecting to D and making it float, and can be used properly depending on the purpose. That is, when a voltage is applied to the conductive member, it can be used as a primary charging unit. Further, the member to be charged such as a photoreceptor is charged with a surface potential
When a DC voltage is applied to achieve the above, a voltage obtained by adding the charging start voltage to V0 may be applied. When the AC voltage is superimposed, the DC voltage may be V0 and the AC voltage may be a peak-to-peak voltage that is twice or more the charging start voltage.

Here, in the above-described embodiment, a specific conductive member is used as a cleaning and neutralizing member, but another example of use will be described below. FIG. 6 shows a so-called titanium dem type electrophotographic apparatus in which a transfer belt 20 is arranged in contact with a plurality of photosensitive drums 21 and a plurality of transfer rollers 22 are arranged in contact with the back surface of the transfer belt 20.

That is, as shown in FIG.
1. The transfer belt 2 is driven by a friction with the transfer roller 22 or a transfer voltage supplied from a power source (not shown) to the transfer roller 22.
The conductive member 2 provided at the position shown in FIG.
3, smoothing, static elimination and the like can be performed.

FIG. 7 shows an image forming apparatus provided with a developing device 24 for rotating the latent image on the photosensitive member with four color developers by rotating the photosensitive member 26 by 90 degrees. The developer image on the photoconductor is transferred to the intermediate transfer member 8 by supplying a voltage to the transfer roller 25 every time the developer image is formed. The developer image on the intermediate transfer member is transferred onto a supplied transfer material. Similarly, in the case of FIG. 9, the electric charge charged on the intermediate transfer body 28 is transferred by the conductive member 27 provided at the illustrated position.
Smoothing, static elimination, etc. can be performed.

As shown in FIG. 10, a conductive member 33 is provided, and the conductive member 33 is brought into contact with the photoconductor 30 from the back surface of the transfer material 32 so that the toner on the photoconductor 30 is transferred to the transfer material. 32.

Further, as shown in FIG. 12, conductive members 33a to 33c are provided and brought into contact with the transfer material 35, the transfer material transporting unit 38, and the fixing unit 34, thereby smoothing the charge and removing the charge. It can also be configured as follows.

In addition, the present invention can be applied to a so-called cleanerless image forming apparatus as shown in FIG.
FIG. 10 shows the charged charger 10 around the photoconductor 106.
1, the arrangement of an exposure portion of the laser beam 102, the developing device 104, the transfer roller 105, and the like is the same as that of a normal electrophotographic apparatus. However, there is no cleaning device for removing the developer remaining on the photoconductor 106 after the transfer. Such an image forming apparatus is configured to collect the residual toner by a developing device. That is, charging and exposure are performed from above the residual developer to form an electrostatic latent image, and when the photosensitive member faces the developing device 104, the developing device 10
The developer is moved by the electric field between the photoconductor 4 and the photoconductor 105,
The development and the cleaning of the photoreceptor are performed simultaneously.

In such an image forming apparatus, the photosensitive member 10
6, the remaining developer is uniformly diffused on the photoconductor 106 downstream of the transfer roller and upstream of the charging charger, so that the next charging is performed uniformly.
06 for the purpose of removing the potential on the photoconductor 106
It is arranged in contact with.

In this case, the shape of the conductive member 108 is blade-like, and the trailing contact is preferable.
At a pressure that does not block the residual toner.
Contact. Needless to say, the voltage may be the same as or opposite to the toner. According to this, the flattening of the residual toner can be reliably performed by the electrical action in addition to the physical action by the contact.

Second, a so-called "recovery" method is used in which the residual toner remaining on the photoreceptor, which cannot be transferred by the transfer means, is prevented from leaking out from the photoreceptor by a cleaning device such as a cleaning blade. Are known.

FIG. 13 shows an example in which a conductive member is used for the recovery. That is, in this case, the shape of the conductive member 110 is preferably blade-like and trailing contact is preferable, and the conductive member 110 is brought into contact with the conductive member 110 at such a pressure that the residual toner is not blocked.

According to this configuration, for example, in the case of an image forming apparatus of a reversal developing system in which primary charging and transfer are opposite in polarity,
As shown in FIG. 11B, a voltage having the same polarity as the primary charging is applied to the recovery, and when the transfer is excessive and the charge having the same polarity as the transfer is placed on the photoconductor, the charge on the photoconductor is removed by the recovery. be able to. In particular, if the charge on the photoconductor 106 is replaced by the negative polarity by the recovery, the potential on the photoconductor can be made uniform by further light elimination.

Here, as shown in FIG. 11, when an image was printed using the cleaning blade as well as the primary charging function in addition to the cleaning function, the frequency of the AC voltage was
100-600 Hz was preferable (1.5 kVp-p
). Further, at 100 Hz or lower, uneven charging due to frequency occurred in the paper traveling direction, and fog appeared on the image at a frequency pitch. At 600 Hz, the surface potential of the photoreceptor could not rise to the DC component of the applied voltage.

When the recovery is conducted to GND in an image forming apparatus of the normal development type in which the primary charging and the transfer are of the same polarity, the surface potential of the entire photosensitive member approaches 0 V, and the light discharging can be omitted. . Further, as described above, even if the recovery is electrically floated or the connection to the GND is made, the effects of smoothing the charge and eliminating the charge can be obtained. Since the recovery also serves as a charge elimination function, a charge eliminator such as a light eliminator or a corona charger can be omitted between the transfer and the charging device.

Third, the conductive member is formed in the shape of a blade, and has the function of a cleaning device for removing paper dust of a transfer material such as residual toner or paper that cannot be transferred by the transfer means and remains on the photosensitive member. The photoconductor can be neutralized.

FIG. 14 shows such a cleaning device constituted by a conductive member. Only the DC voltage is used for the voltage. That is, in this case, it is the same as the above-mentioned "recovery" that the electric action and the static elimination device such as the corona charger can be omitted. However, in contrast to the recovery in which the charge is smoothed or the charge is removed / charged while the toner is interposed therebetween, the blade is in direct contact with the photoconductor, so that a further effect is recognized.

Toner or paper powder adheres to the transfer belt or the intermediate transfer member from a transfer material such as a photoreceptor or paper. To transfer a good toner image, the toner or paper powder is removed from the transfer belt or the intermediate transfer member. There is a need to. The fixing device applies oil to the fixing roller when fixing the transfer material. When the oil in the fixing device is excessive, it is necessary to remove the oil from the fixing roller. Further, since toner and paper powder adhere to the fixing roller, it is necessary to remove the toner and paper powder from the fixing roller. The conductive member may be used to prevent the removed toner, paper dust, and oil from leaking out, and may also have the function of removing toner, paper dust, and oil, and may perform charge smoothing and static elimination / charging. .

On the other hand, the blade-shaped conductive member can be used as a charging device for performing primary charging while having the function of a cleaning device for removing residual toner and paper dust remaining on the photoreceptor that cannot be transferred by the transfer means. . As described above, when a DC voltage is applied in order to bring a charged body such as a photoconductor to a surface potential V0, a voltage obtained by adding a charging start voltage to V0 may be applied, and when an AC voltage is superimposed. The DC voltage may be V0 and the AC voltage may be a peak-to-peak voltage that is at least twice the charging start voltage. The primary charging device such as a corona charger can be omitted because the blade also has the function of a charging device that performs cleaning and primary charging.

FIG. 15 shows another example of the shape of the conductive member. This conductive member includes a block 11 (see FIG. 2A) including a portion 11a having a high density of the conductive agent and a portion 11b having a small density, and a roller 12 having a shaft 13 having a high density of the conductive agent at the center (see FIG. b)), a portion 15a having a high density of the conductive agent and a portion 15 having a small density
15 (see FIG. 2C), and a blade 16 in which a portion 16a having a high density of the conductive agent and a portion 16b having a small density are bonded in the short direction.
(See FIG. 2 (c)). The blade-shaped member may be in a trail contact or an agenst contact. Although the embodiment of the present invention has been described above, it is needless to say that various changes can be made without changing the gist of the present invention.

[0070]

As described in detail above, according to the present invention,
It is possible to provide an image forming apparatus which realizes suppression of noise generation, particularly when the conductive member is brought into contact with a photoreceptor or the like, in which the resistance can be easily controlled, and therefore, the charging and discharging functions are excellent. .

[Brief description of the drawings]

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

FIG. 2 is a diagram illustrating a configuration of a cleaning blade employed in a second embodiment.

FIG. 3 is a diagram showing a configuration of centrifugal molding.

FIG. 4 is a diagram showing hardness, Young's modulus, rebound resilience, and resistance for each sample.

FIG. 5 is a diagram illustrating a change in potential when a conductive member employed in the image forming apparatus according to the first embodiment is electrically floated and brought into contact with a photosensitive member.

FIG. 6 is a diagram illustrating a change in potential when a conductive member employed in the image forming apparatus according to the first embodiment is electrically connected to GND and brought into contact with a photosensitive member.

FIG. 7 is a diagram illustrating a change in potential when a voltage applying unit is connected to a conductive member employed in the image forming apparatus according to the first embodiment and is brought into contact with a photoconductor;

FIG. 8 is an application example of the first embodiment, and is a diagram illustrating a state of smoothing a charge of a transfer belt.

FIG. 9 is an application example of the first embodiment, and is a diagram illustrating a state in which an intermediate transfer member is subjected to charge smoothing and the like.

FIG. 10 is an application example of the first embodiment, and is a diagram illustrating a state of use as transfer.

FIG. 11 is an application example of the first embodiment, and includes a transfer material,
FIG. 4 is a diagram illustrating a state in which a transfer material transporting unit, a fixing unit, and the like are smoothed by charge;

FIG. 12 is an application example of the second embodiment, and is a diagram illustrating a state where a charging member is used without a cleaner.

FIG. 13 is an application example of the second embodiment, and is a diagram illustrating a state in which a cleaning blade has a primary charging function.

FIG. 14 is an application example of the second embodiment, and is a diagram showing a state in which recovery has a function of removing electricity.

FIG. 15 is a diagram showing an example of the shape of a conductive member employed in the first embodiment.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Photoreceptor drum 2 Charger 3 Laser 4 Developing device 5 Transfer charger 6 Paper 7 Conductive cleaning 8 Light eliminator

Continued on the front page F term (reference) 2H003 CC04 CC05 2H032 AA05 2H033 AA40 BA50 BA54 2H034 BF02 BF04

Claims (10)

[Claims] A charging unit configured to charge an image carrier; a latent image forming unit configured to form an electrostatic latent image on the image carrier; and a developing unit configured to supply a developer to the electrostatic latent image to perform development. Transport means for transporting the material to be transferred; transfer means for transferring the developer image formed by the developing means onto the material to be transferred; and development on the material to which the transfer has been performed by the transfer means. A fixing unit for fixing the developer image, and a member containing a powder contained in a base material. The fixing unit is in contact with any one of the image carrier, the transfer unit, the conveying unit, the transfer unit, and the fixing unit, and includes a contact portion. An image forming apparatus comprising: a contact member having a lower powder distribution density than other parts. 2. A charging device for charging an image carrier, a latent image forming device for forming an electrostatic latent image on the image carrier, and a developing device for supplying a developer to the electrostatic latent image to perform development. Transport means for transporting the material to be transferred; transfer means for transferring the developer image formed by the developing means onto the material to be transferred; and development on the material to which the transfer has been performed by the transfer means. A fixing unit for fixing the developer image, and a member containing a powder contained in a base material. The fixing unit is in contact with any one of the image carrier, the transfer unit, the conveying unit, the transfer unit, and the fixing unit, and includes a contact portion. An image forming apparatus comprising: a contact member having a lower powder distribution density than other portions, and a contact portion having a higher rebound resilience than the other portions. 3. The image forming apparatus according to claim 1, wherein a rebound resilience of the contact member is 40 ° C. or less (JIS-A). 4. The image forming apparatus according to claim 1, wherein the powder contains a substance insoluble in a base material. 5. The image forming apparatus according to claim 1, wherein the powder contained in the contact member contains a conductive material. 6. The apparatus according to claim 1, further comprising means for applying a voltage including at least an AC component to said contact member.
An image forming apparatus according to claim 1. 7. The image forming apparatus according to claim 1, wherein the contact member has a blade shape. 8. The image forming apparatus according to claim 7, wherein the contact member is at least one of a charging blade, a charge removing blade, and a recovery blade. 9. A charging device for charging an image carrier, a latent image forming device for forming an electrostatic latent image on the image carrier, and a developing device for supplying a developer to the electrostatic latent image to perform development. Conveying means for conveying the material to be transferred; transfer means for transferring the developer image formed by the developing means onto the material to be transferred; and development on the material to which the transfer has been performed by the transfer means. A fixing means for fixing the developer image, and a member containing powder in a substrate, provided in contact with the image carrier, and a distribution density of powder in a contact portion is higher than in other portions. An image forming apparatus comprising: a cleaning unit configured to clean the small image carrier after the transfer. 10. The image forming apparatus according to claim 9, wherein the cleaning unit cleans the image carrier and removes electricity from the image carrier.