JP2001310998A - Conductive member - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an inexpensive conductive member having a good electrification property usable in a contact electrification device and a durability, and which is easily manufactured. SOLUTION: It is formed by single structures which comprises a high polymer base material containing a conductive agent in conductive members 10A-10D used by contacting with a body to be contacted. The distributing density of the agent in 12A-12D, the neighborhood of contact parts with the body to be contacted, is smaller than that in the other parts or set to be substantially zero. The base material is formed by at least one sort of polyester selected from ester-based polyurethane.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to a conductive member,
In particular, the present invention relates to an electrophotographic photosensitive member, a transfer drum and a transfer belt used in a transfer process, or an intermediate conveyance belt, and a conductive member suitable for charge flattening, charge elimination, and charging of a developing blade used in a development process. .

[0002]

2. Description of the Related Art As a charging device, a corona charger utilizing corona discharge and a contact charging device are known. The corona charger needs to apply a high voltage of 4 to 8 kV to the wire, and it is necessary to separate the wire from the case in order to prevent current from leaking from the wire to the case surrounding the wire, resulting in an increase in size. Also, most of the discharge current of the wire flows into the case, and a large amount of discharge is required to secure a necessary current amount on the photoconductor side. Accordingly, a large amount of ozone is generated, and the components of the apparatus are oxidized and the surface of the photoreceptor is deteriorated to easily cause image blur, and there is a danger of harm to the human body. Therefore, in recent years, in order to overcome these disadvantages of the corona charger, a contact charging device has been often used.

[0003] A contact charging device can charge an object to be charged such as a photoreceptor at a lower voltage than a corona charger, and can be reduced in size as compared with a corona charger, contributing to downsizing of the device. ing. Further, the amount of generated ozone is as small as about 1/10 to 1/100 of the corona charger. As the contact charging device, a conductive brush, a roller having a single-layer structure, and a roller or blade having a multi-layer structure are known.

However, in a brush withstand device using a conductive brush containing carbon in a fiber such as rayon, the brush cannot be prevented from coming off, causing the current to leak to another charging device, or causing a problem. At the same time, the hair may spread and the current may leak to the vicinity. In addition, there is a problem that the charging tends to be non-uniform, minute unevenness of the electric potential is generated on the surface of the photoreceptor, and white streaks or black streaks are generated in the image.

On the other hand, a single-layer conductive member such as a roller has a problem that a voltage applied when the photosensitive member has a defect such as a scratch leaks to the photosensitive member. Further, it is difficult to control the resistance depending sensitively on the amount of the conductive agent added to the substrate.

A conductive member having a multilayer structure such as a roller coated with a tube has a complicated structure and is expensive.

Further, there is a possibility that a conductive material such as a blade having an insulating layer applied or adhered to a conductive base material may be exposed or peeled off when the insulating layer is worn. Also, a blade in which a conductive agent is applied to an insulating base material may similarly cause peeling of the conductive layer. Also, it is more expensive than a single structure.

To solve such a problem, Japanese Patent Laid-Open Publication No.
As disclosed in Japanese Patent Application Publication No. 000-39755, the conductive member is formed in a single structure composed of a polymer base material, and the distribution density of the conductive agent in the vicinity of the contact portion with the photoconductor is smaller than or substantially equal to other portions. It has been proposed to provide a zero layer. According to this, it is possible to improve the wear resistance and to manufacture at low cost.

[0009]

However, in a conductive member in which the distribution density of the conductive agent in the vicinity of the contact portion is smaller than or zero in other portions, the abrasion resistance and the resistance to hydration depend on the material constituting the polymer base material. There is a problem that the degradability varies.

The raw material constituting the polymer base material is preferably in a liquid state in order to add a conductive material. In this case, the wear resistance of the base material itself is poor due to the poor wear resistance of the polymer. Problem.

In view of such circumstances, an object of the present invention is to provide a conductive member which can be favorably charged by using a contact charging device, has durability, is easy to manufacture, and is inexpensive. I do.

[0012]

According to a first aspect of the present invention, there is provided a conductive member which is used in contact with an object to be contacted. The distribution density of the conductive agent in the vicinity of the contact portion with the contacted body is smaller or substantially zero other portions, and the polymer base material is at least one kind selected from ester polyurethane. The conductive member is made of polyurethane.

A second aspect of the present invention is the conductive member according to the first aspect, wherein the polyurethane is a caprolactone-based polyurethane.

According to a third aspect of the present invention, in the second aspect, the polymer substrate is made of a polyurethane in which a caprolactone-based polyurethane is blended with an ether-based polymer in an amount of 1% by weight or less. In the member.

According to a fourth aspect of the present invention, in the second aspect, the polymer substrate is made of a polyurethane obtained by blending a caprolactone-based polyurethane with 30% by weight or less of another ester-based polymer. Conductive member.

According to a fifth aspect of the present invention, there is provided a conductive member according to any one of the first to fourth aspects, wherein the raw material polymer for forming the polymer base material has a molecular weight of 1,000 to 4,000. is there.

According to a sixth aspect of the present invention, in any one of the first to fifth aspects, the range in which the distribution density of the conductive agent is smaller than or substantially zero in other parts is equal to the range of the contacted object. In the range from the contact end to the inner side of 2 to 120 μm.

According to a seventh aspect of the present invention, in any one of the first to sixth aspects, the true density of the conductive agent particles or the specific gravity of the particles containing the conductive agent is higher than the specific gravity of the polymer base material. A conductive member characterized by being large.

An eighth aspect of the present invention is the conductive member according to the seventh aspect, wherein the polymer base material containing the conductive agent is manufactured by centrifugal molding.

A ninth aspect of the present invention is the conductive member according to any one of the first to eighth aspects, wherein the conductive agent of the conductive member contains at least carbon black.

According to a tenth aspect of the present invention, in any one of the first to ninth aspects, the conductive agent of the conductive member contains at least carbon black as a main component, and further includes an ionic conductive agent and a carbon black dispersant. A conductive member containing at least one selected from the group consisting of:

In a conductive member which comes into contact with a charged body such as a photoreceptor, an insulating layer is provided at a contact portion with the charged body so that when a voltage is applied, a voltage applied to a scratch on the charged body such as a photoreceptor is reduced. Although it is known that leakage can be prevented, the present invention uses a kind of polyurethane selected from ester-based polyurethane as a single structure of a polymer base material, and uses a member to be contacted (= charged member such as a photoreceptor). The distribution density of the conductive agent at the contact portion with the body is lower than that of the other portion, or the conductive agent is substantially absent.

The present invention is based on the finding 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, irrespective of the electric resistance of the portion where the distribution density of the conductive agent is large. Accordingly, a conductive member having a desired electric resistance can be easily formed. If the distribution density of the conductive agent is low or nonexistent, the resistance of the conductive member is determined by the distribution of the conductive agent if the electrical resistance is sufficiently high (for example, three digits or more in volume resistance) relative to the portion where the distribution density of the conductive agent is high. It becomes dominated by the electrical resistance of the portion where the density is low. Therefore, the electric resistance of the conductive member of the present invention is hardly affected by the electric resistance of the portion where the distribution density of the conductive agent is large, so that it is not necessary to strictly control the amount of the conductive agent to be contained, and it is easy to control. is there. In the 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.

Some conventional conductive members have a conductive base material with an insulating layer attached thereto. For example, a roller coated with a tube of an insulating layer or the like, or a blade coated or pasted with an insulating layer may be used. However, by coating, applying, or attaching the insulating layer, the structure of the conductive member becomes complicated and expensive, and the insulating layer may peel off during wear. Further, there is a similar fear that a conductive layer is coated, applied, or attached to an insulating base material.

In the conductive member of the present invention, it is limited that a kind of polyurethane selected from ester polyurethane is used as a simple structure of the polymer base material, and it is further limited that a caprolactone polyurethane is particularly used among ester polyurethanes. At the same time, a portion where the distribution density of the conductive agent is small or absent is in contact with a charged member such as a photoreceptor, so that the durability of the insulating substrate against the inherent friction can be brought out. In addition, it is possible to prevent the conductive agent from being damaged due to abrasion of the conductive member due to contact with the member to be charged and damaging the member to be charged. Furthermore, since it is a single unit structure, the structure is simple and inexpensive, and problems such as peeling can be prevented.

The conductive member of the present invention has a block shape,
Any of a roller shape and a blade shape may be used. The blade-shaped member may be used for either trail contact or against contact.

FIG. 1 shows examples of conductive members of various shapes. The conductive member 10A of (A) is a block structure having a single structure, most of which is formed of a conductive portion 11A, and has a non-conductive portion 12A having a relatively low density of a conductive agent on one end surface side. The non-conductive portion 12A is used in contact with the photosensitive member 1 as a contacted member.

The conductive member 10B of (B) is a roller having a single structure, in which a roller layer comprising a conductive portion 11B and a non-conductive portion 12B on the surface is provided on a core metal 13B.

The conductive member 10C of (C) has a blade shape and has a non-conductive portion 12C on one end surface in the thickness direction of the conductive portion 11C. The conductive member 10
C is not particularly limited as long as the non-conductive portion 12C is brought into contact with the photoconductor 1.
Photoconductor 1
May be an abutting contact that rotates counterclockwise.

The conductive member 10D of (D) has a blade shape, but has a non-conductive portion 12D at one longitudinal end of the conductive portion 11D. The usage mode is the same as that of the conductive member 10C.

As described later, the conductive member is preferably made of an elastic body or a flexible material, and the thickness of the portion where the distribution density of the conductive agent is small is preferably 2 to 120 μm. The blade shape has a smaller occupation ratio of the portion where the distribution density of the conductive agent is large as compared with other shapes, so that the content of the conductive agent with respect to the base material can be reduced, and the problem of excessive conductive agent described later hardly occurs. ,preferable.

The conductive agent used for the conductive member of the present invention is:
Any material having electric conductivity such as carbon black and metal powder and insoluble in a polymer base material such as a rubber member may be used. In particular, carbon black is relatively inexpensive, easily has a three-dimensional structure, and can exhibit conductivity with a relatively small amount than metal powder. Carbon black has an advantage that conductivity is hardly affected by temperature and humidity. The type of carbon black is not particularly limited, and examples thereof include Ketjen Black (manufactured by Lion Corporation) and Toka Black # 5500 (manufactured by Tokai Carbon Co., Ltd.).

On the other hand, carbon black and metal powder need to be contained in a relatively large amount because conductivity is exhibited by direct contact between fillers, and there is a possibility that physical properties of the rubber member may be deteriorated. On the other hand, the ionic conductive agent can exhibit conductivity with a small amount of addition, and has an advantage of not deteriorating the physical properties of the base material containing the conductive agent. For this reason, in the case where carbon black or metal powder alone has insufficient conductivity, an ionic conductive agent can be used supplementarily. The ionic conductive agent is not particularly limited, and examples thereof include lithium perchlorate. Further, a carbon black dispersant may be used in addition to the ionic conductive agent. Examples of the carbon dispersant include Dispalon DA-703-50 (trade name: manufactured by Kusumoto Kasei Co., Ltd.). The ion conductive agent and the carbon black dispersant may be used alone or in combination.

When both carbon black and an ionic conductive agent or a carbon black conductive agent are used in combination, conductivity can be exhibited by adding a smaller amount of carbon black than when carbon black is used alone, and the physical properties of the substrate can be improved. It is possible to have a property that the conductivity is hardly affected by temperature and humidity, which is a merit of carbon black, without lowering.

That is, it is preferable to use carbon black alone to exhibit conductivity or to use both together.

Such a conductive agent may be added to the polymer base material itself, but in the present invention, the conductive agent is previously added to the ester-based polymer or the ether-based polymer.

The polymer used in the masterbatch is preferably a liquid at room temperature for stabilizing the dispersion. However, if the abrasion resistance of the polymer is inferior, the abrasion resistance of the base material itself is inferior. Therefore, it is possible to suppress the degree of reduction in the abrasion resistance and hydrolysis resistance by limiting the type and the amount of the polymer. it can. The polymer of the present invention uses at least one of an ester-based polymer and an ether-based polymer, and the compounding amount is preferably 1% by weight or less for an ether-based polymer, and 30% by weight or less for an ester-based polymer. Is preferred.

The molecular weight of the polymer as the raw material of the polymer substrate is preferably from 1,000 to 4,000. It is because if it deviates from this, it is not preferable in terms of handling properties and workability when dispersing the conductive agent.

The true density of the conductive agent particles or the specific gravity of the particles containing the conductive agent is preferably larger than the specific gravity of the polymer base material. This is because it is necessary to reduce the distribution density of the dispersant in the vicinity of the contact portion of the conductive member of the present invention with the contacted body or to make the conductive agent substantially absent. Here, the true density is not the bulk density in the apparent volume of particles having large irregularities such as carbon black, but the density in the volume when all the gaps are eliminated. Further, the particles include powder, short fiber, flake, etc., in addition to what is generally called particles. Further, as particles for supporting or attaching the conductive agent, glass particles, high-density resin particles, and the like can be given.

Although there is no particular limitation on the method for producing a conductive member in which the distribution density of the conductive agent is smaller or substantially zero at the contact portion with the member to be charged such as a photoreceptor, there is no particular limitation. Is preferred. If the true density of the conductive agent is made larger than the specific gravity of the substrate, the conductive agent will settle even in static molding. This means that even when the conductive agent is carried or adhered to other particles,
The same applies if the specific gravity of the particles is greater than the specific gravity of the substrate. However, when the viscosity of the base material is large, when the specific surface area of the conductive agent is large, or when the curing speed of the base material is faster than the settling speed of the conductive agent, the settling of the conductive agent does not proceed,
In such a case, centrifugal molding is preferable because a portion having a sufficiently low distribution density of the conductive agent cannot be obtained.

In the centrifugal molding method, in order to promote the sedimentation of the conductive agent, a molding material is charged into a rotating drum of a centrifugal molding machine, and the molding is performed while rotating the drum at a predetermined rotation speed. That is, the material may be charged into the rotating drum and the drum may be formed while rotating at a predetermined rotation speed. After a base layer for forming a mold surface is formed in the drum, a molding material may be charged.

FIG. 2 shows an example of a centrifugal molding apparatus. As shown in FIG.
1 has a cylindrical shape 23 in which the center of the bottom is fixed to one end of a rotating shaft 22 driven to rotate. The cylindrical mold 23 is held in a box-shaped heating jacket 24, and the opening of the heating jacket 24 is closed by a lid 25. On the outer periphery of the heating jacket 24, a heating passage 26 for flowing a heating fluid is provided.
7 covered.

Using such a device, a cylindrical mold 23 is
When a material in which a carbon black conductive agent is mixed into a polymer base material is charged and the cylindrical mold 23 is rotated, the conductive agent having a high true density is rapidly transferred to the inner surface side of the cylindrical mold 23 by centrifugal force due to the rotation. Movement is promoted. That is, when the true density of the conductive agent is larger than the density of the base material, the distribution density of the conductive agent increases toward the drum mold surface side of the conductive member, and the distribution density is sufficiently small on the air surface side or the conductive density is low. The agent is substantially absent. Therefore, when the conductive member is formed by centrifugal molding, the air surface side of the conductive member is brought into contact with a member to be charged such as a photosensitive member.

The surface of the conductive member on the drum mold surface side picks up irregularities on the drum mold surface, whereas the drum air surface has no irregularities. After the rotation of the drum is stopped, one end is cut to form a sheet, aged as necessary, and especially if the conductive member is cut so that the longitudinal direction is along the circumferential direction, the thickness is uniform. A conductive member can be obtained. Further, the thickness of the conductive member can be controlled by the amount of the material to be charged into the drum.

In the centrifugal molding method, a material containing a relatively large amount of a conductive agent is charged as a first layer, and a material in a semi-cured state and containing a relatively small or no conductive agent is charged. In addition, it is possible to obtain a conductive member having a single structure and having a sufficiently low or no distribution density on one surface side. Furthermore, similarly, by supplying two types of materials in a mold in a laminated state and press-molding, it is possible to obtain a conductive member having a single structure and a distribution density on one surface side is sufficiently small or absent. it can.

In the conductive member of the present invention, the range where the distribution density of the conductive agent is small or the conductive agent is substantially absent is the viscosity and curing speed of the polymer base material, the specific gravity of the polymer base material and the conductive agent. The difference and affinity, the particle size and shape of the conductive agent, the type and amount of the conductive agent, and the like, and in the case of centrifugal molding, can be controlled by the magnitude of the centrifugal force generated by rotation of the drum.

For example, the true density of carbon black (Toka Black # 5500) used as a conductive agent is 1.
The specific gravity of the caprolactone-based polyurethane used as the polymer base material is about 1.0 to 1.3. Therefore, it is preferable to use polyurethane as the polymer substrate from this point as well, and it is possible to easily form a portion where the distribution density of the conductive agent is low or where the conductive agent is not present.
When the specific gravity of the polymer base material is larger than the true density of the conductive agent, the conductive agent may be used by being attached to, for example, glass particles having a specific gravity of 2.5.

In the conductive member of the present invention, the range in which the distribution density of the conductive agent is small or the conductive agent is substantially absent is preferably in the range from the contact end to 2 to 120 μm inside the contact end.

This is a range recognized from the results of the test. The range in which the distribution density of the conductive agent is small or substantially absent is preferably 100 μm or less, and practically up to 120 μm.

The thickness of the portion where the distribution density of the conductive agent is small is 1
It was confirmed that the charging agent was present in some places near the surface of the conductive member when the thickness was less than 0 μm. Although not suitable for long life, it can be applied to short life printers and the like.
However, in order to prevent leakage to the photoconductor, 10M
A resistor of about Ω had to be provided between the power supply and the conductive member. The resistance of the conductive member was the first half of the 10 <5> ([Omega] .cm) generation.

Further, in the conductive member of the present invention, it is particularly preferable to use carbon black as the conductive agent. The preferable range of the addition amount is, for example, polyurethane is used as the polymer base material and carbon black is mixed in various kinds. It could be confirmed by adding and centrifuging. The thickness of the portion where the distribution density of the conductive agent is small or absent is 40 μm.
The production conditions were adjusted to be m.

As a result, when Toka Black # 5500 (manufactured by Tokai Carbon Co., Ltd.) was used as the carbon black, the volume resistivity became 5 × 10 ⁸ Ω · cm or less.
The content of the carbon black alone with respect to the polymer base material for expressing conductivity was in the range of 0.1 to 5.0 wt% (weight percent). If it is less than 0.1 wt%, the conductivity cannot be sufficiently exhibited, which is not preferable. On the other hand, when the content is 5.0 wt% or more, the 100% permanent elongation increases as compared with the base material.
When the photosensitive member is brought into contact with the photosensitive member at a high pressure of about / cm, the base material is deformed and the contact force is reduced, so that the photosensitive member cannot be used for a long life.
Further, when the amount of carbon black is increased, there is a problem that a good air surface cannot be obtained due to an increase in viscosity due to excessive addition of carbon black during centrifugal molding. Furthermore, if carbon black is present near the air surface, there are problems such as leakage of current to a flaw on the member to be charged, and loss of carbon black due to friction.

The carbon black content is 0.1 to 5.0.
In the range of wt%, there is no problem with the carbon black aggregate and the increase in viscosity, and the compression set characteristic is slightly deteriorated as compared with the base material. The resistance variation was small and the compression set characteristics were satisfied, and the most preferable range was 0.5 to 2.5 wt%.

Further, lithium perchlorate was used in combination as an ion conductive agent. By using the ionic conductive agent together, sufficient conductivity can be obtained and the variation in electric resistance can be suppressed even when the carbon black content is reduced. The content with respect to the base material so that the volume resistance was 5 × 10 ⁸ Ω · cm or less was in the range of 0.5 to 5.0 wt% (weight percent). If the content is less than 0.01 wt%, the effect of the ionic conductive agent cannot be sufficiently exhibited. On the other hand, when the content is 5.0 wt% or more, the ionic conductive agent gradually seeps out of the conductive member and causes contamination of the photoreceptor, which is not practical. The ion conductive agent content is 0.01 to 5.0 wt%
In the range, there was no exudation of the ion conductive agent, and the abrasion characteristics were slightly deteriorated as compared with the base material alone, but this was a range in which there was no problem. The resistance variation was suppressed, and the friction characteristics were satisfied. The most preferable range was 0.05 to 1.0 wt%.

Therefore, by mixing the carbon black and the ionic conductive agent as the conductive agent, the amount of each added can be reduced, and the lower limits of the contents of both the carbon black and the ionic conductive agent are widened. There is an advantage that there is no danger of causing a problem when the content is excessively contained.

The functions of the conductive member of the present invention include smoothing and smoothing the charge on the member to be charged by contact with the member to be charged such as a photoreceptor, and discharging and charging.

Such a function can be achieved by using a member to be charged as a photosensitive member,
This will be described with reference to FIG. When the conductive member of the present invention is electrically floated and brought into contact with the photoreceptor, when the state where the electric charge is locally applied on the surface of the photoreceptor is extremely different from the surroundings, the electric conductive member is charged. The state is made to work with the surroundings, and the charge is smoothed. For example, when the positive polarity transfer is excessive in the reversal development in which the negative polarity primary charging is performed, as shown in Fig. (A-1), the positive polarity charge is applied to the photoconductor surface corresponding to the outside of the transfer material. Then, a charge of negative polarity is placed on the surface of the photoconductor corresponding to the inside of the transfer material, and a step Va is generated in the surface potential V of the photoconductor corresponding to the end of the transfer material. The portion on which the positive polarity charge is applied cannot rise to a desired potential at the time of the next primary charge, causing unnecessary toner to adhere to the photoreceptor, fog on the image, and uneven density in the halftone. Occurs. However, by bringing the electrically floating conductive member into contact with the photoreceptor, as shown in FIG. It is possible to alleviate the adhesion of unnecessary toner on the photoreceptor and the fogging of the image due to the smoothing.

When the conductive member is electrically connected to GND and brought into contact with the photoreceptor, the charge on the photoreceptor acts in the direction of moving in the GND direction (= removal), smoothes the charge, and smoothes the photoreceptor. The surface potential V approaches 0V. As described above, in the case of reversal development in which primary charging is performed with negative polarity, when positive charge is applied to the photoconductor during transfer (FIG. (B-1)),
The electric charges can be flattened (FIG. (B-2)), and unnecessary toner can be prevented from adhering to the photoreceptor and the image can be prevented from being fogged.

Further, when a voltage applying means (= high-voltage transformer) is connected to the conductive member of the present invention and brought into contact with the photoreceptor (FIG. (C-1)), as shown in FIG. It is possible to more reliably remove the charge on the photoconductor than by the above-described method, and it is possible to prevent unnecessary toner from adhering to the photoconductor and fog on an image.

That is, the ability of the conductive member to smooth or remove the charge on the photoreceptor is effective in the order of applying a voltage, connecting to GND, and making it float, and can be used depending on the purpose.

When a voltage is applied to the conductive member,
It can be used as primary charging means. When a DC voltage is applied to a charged object such as a photoconductor to make the surface potential V ₀ , a voltage obtained by adding a charging start voltage to V ₀ may be applied. When the AC voltage is superimposed, the DC voltage may be V ₀ and the AC voltage may be a peak-to-peak voltage that is twice or more the charging start voltage.

The member to be charged is not limited to the photoreceptor, but may be any member for smoothing charge or charging.

For example, the transfer belt or the intermediate transfer member that comes into contact with the photoreceptor via a transfer material such as paper is smoothed or neutralized / charged, and the toner on the photoreceptor contacts the photoreceptor from the back side of the transfer material. May be transferred to a transfer material.

FIG. 4 shows an example of such a mode of use.
2A, a plurality of photosensitive members 31 are provided in contact with a rotationally driven transfer belt 32, and the transfer belts 32 of the photosensitive members 31 are provided.
, A transfer roller 33 is provided on the opposite side of
The conductive member 30 of the present invention is disposed, for example, so as to contact the transfer belt 32.

(B) is provided so that the intermediate transfer member 34 is brought into contact with the photosensitive member 31 with the transfer roller 33A interposed therebetween, and the transfer material 35 contacts the intermediate transfer member 34 by the transfer roller 33B. Is done. In such a configuration, the developing device 3
The image formed by 6 is transferred to the transfer material 35 via the intermediate transfer member 34, and the conductive member 30 of the present invention is disposed, for example, so as to contact the inside of the intermediate transfer member 34.

Further, (C) is to transfer the image formed by the developing device 36 to the transfer material 35 by bringing the transfer material 35 into direct contact with the photoreceptor 31, and the conductive member 30 of the present invention For example, the transfer material 35 is provided so as to contact the opposite side of the photoconductor 31 from the transfer material 35. FIG. 5 shows still another use mode. In such an embodiment, the transfer material conveying means 37
Is supplied between the photosensitive member 31 and the transfer material roller 38, and then between the pair of fixing rollers 39a of the fixing unit 39. In such a case, for example, the conductive member of the present invention may be brought into direct contact with the transfer material 35 (conductive member 30A) or provided in contact with the transfer material transporting means 37 (conductive member 30).
B), it may be provided in contact with the fixing roller 39a (conductive member 30C).
Charging can be performed.

FIG. 6 shows another mode of use.
Such an embodiment indicates use as a developing blade in a one-component developing device. Here, the developing device 36 is provided in contact with a toner supply roll 42 provided in a toner container 41 in which toner is held, and the photoconductor 31 is provided so as to be in contact with the developing device 36. The conductive member 30
The developing device 36 is disposed so as to be in contact with the outlet side of the toner container 41 and is used as a developing blade for regulating the thickness of the toner layer formed on the developing device 36. In this case, applying the same bias to the conductive member 30 as the developing bias (for example, negative polarity) prevents the toner of the opposite polarity from adhering to the developing device 36. Furthermore, since the distribution density of the conductive agent is low or the conductive agent does not exist in the portion of the conductive member 30 that is in sliding contact with the developing device 36, leakage of voltage to the scratches of the developing device 36 is prevented and the durability is excellent. There are advantages.

When the conductive member of the present invention is used as a cleaning device, it is necessary to increase the contact pressure in order to clean the residual toner on the photoreceptor, and it is necessary to have durability against abrasion. As in the present invention, by contacting the photoreceptor with a portion where the distribution density of the conductive agent is small or absent, durability performance against abrasion of a polymer base material such as polyurethane used for the base material can be obtained. Further, the conventional one in which an insulating layer is bonded to a blade-shaped base material has problems such as easy peeling of the bonding due to friction between the photoreceptor and the blade, and a complicated manufacturing process. Therefore, it is advantageous to have a unitary structure as in the present invention.

[0069]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described based on embodiments, but the present invention is not limited to these embodiments.

(Example 1) Table 1 shows the composition of Example 1.

As shown in the following formulation, 72% by weight of polyester polyol (PCL220N: manufactured by Daicel Chemical Co., Ltd.), which is an ester polymer, was heated and dissolved, and carbon black (Toka Black # 5500: manufactured by Tokai Carbon Co., Ltd.) was added thereto. At room temperature, 26.6% by weight of a liquid ester polymer (P-2010: manufactured by Kuraray Co., Ltd.) to which 4% by weight was added was mixed, and 1,4-diphenylmethane diisocyanate was added.
(MDI) was reacted to prepare a prepolymer.

Then, 1,4-butanediol and trimethylolpropane were mixed at a mixing ratio of 67:33 at the following mixing ratio, and the mixture was poured into a preheated centrifugal molding drum, and the low-speed ( Heat-curing was performed while rotating at a centrifugal force of 75 G) to form a caprolactone-based polyurethane. The true density of the carbon black used was 1.
8, and the specific gravity of the prepolymer serving as the base material is 1.16.
Met.

After the molding, the rubber blade was cut to a predetermined size to be bonded to a metal holder. After curing the adhesive,
The rubber blade and the holder were electrically connected with a conductive carbon paste to form a conductive blade.

(Example 2) Table 1 shows the composition of Example 2.

As shown in the following formulation, 72% by weight of a polyester polyol (PCL220N: manufactured by Daicel Chemical Co., Ltd.) was heated and dissolved, and 1.4% by weight of carbon black (Toka Black # 5500: manufactured by Tokai Carbon Co., Ltd.) was added thereto. A conductive blade was formed in the same manner as in Example 1 except that 26.6% by weight of the obtained polyester polyol (PCL220N: manufactured by Daicel Chemical Co., Ltd.) was mixed.

(Example 3) Table 1 shows the composition of Example 3.

As shown in the following formulation, 71% by weight of a polyester polyol (PCL220N: manufactured by Daicel Chemical Co., Ltd.) was heated and dissolved, and 1.4% by weight of carbon black (Toka Black # 5500: manufactured by Tokai Carbon Co., Ltd.) was added thereto. 26.6% by weight of a polyester polyol (PCL220N: manufactured by Daicel Chemical Co., Ltd.) and 0.1% by weight of an ionic conductive agent (lithium perchlorate) are added. A conductive blade was formed in the same manner as in Example 1 described above, except that it was mixed with the same by weight.

Example 4 Table 1 shows the composition of Example 4.

As shown in the following formulation, 67% by weight of a polyester polyol (PCL220N: manufactured by Daicel Chemical Co., Ltd.) was heated and dissolved, and 1.4% by weight of carbon black (Toka Black # 5500: manufactured by Tokai Carbon Co., Ltd.) was added thereto. 3. Ester polymer (P-2010: manufactured by Kuraray Co., Ltd.) to which 26.6% by weight of the obtained polyester polyol (PCL220N: manufactured by Daicel Chemical) and 0.5% by weight of an ionic conductive agent (lithium perchlorate) are added. A conductive blade was formed in the same manner as in Example 1 except that 5% by weight was mixed.

(Example 5) Table 1 shows the composition of Example 5.

As shown in the following formulation, 71% by weight of a polyester polyol (PCL220N: manufactured by Daicel Chemical Industries, Ltd.)
Is heated and dissolved, and 26.6% by weight of a polyester polyol (PCL220N: manufactured by Daicel Chemical Co., Ltd.) to which 1.4% by weight of carbon black (Toka Black # 5500: manufactured by Tokai Carbon Co., Ltd.) is added, and an ionic conductive agent ( A conductive blade was formed in the same manner as in Example 1 except that the mixture was mixed with 0.9% by weight of an ester-based polymer (P-2010: manufactured by Kuraray Co., Ltd.) to which 0.1% by weight of lithium perchlorate was added. did.

(Comparative Example 1) Table 1 shows the composition of Comparative Example 1.

For comparison, a polyester polyol (PCL220N:
A blade was formed in the same manner as in Example 1 except that 100 parts by weight of Daicel Chemical Co., Ltd.) was used.

(Comparative Example 2) Table 1 shows the composition of Comparative Example 2.

For comparison, as shown in the following composition, 67 parts by weight of a polyester polyol (PCL220N: manufactured by Daicel Chemical Co., Ltd.) was dissolved by heating, and carbon black (Toka Black # 5500: manufactured by Tokai Carbon Co., Ltd.) was added thereto.
Ester polymer (P-
2010: Kuraray Co., Ltd.) 26.6% by weight and an ionic conductive agent (lithium perchlorate) 0.5% by weight of an ester polymer (P-2010: Kuraray Co., Ltd.) 4.5% by weight. Except for mixing, a conductive blade was formed in the same manner as in Example 1 described above.

Comparative Example 3 Table 1 shows the composition of Comparative Example 3.

For comparison, as shown in the following formulation, 67 parts by weight of a polyester polyol (PCL220N: manufactured by Daicel Chemical Co., Ltd.) was heated and dissolved, and carbon black (Toka Black # 5500: manufactured by Tokai Carbon Co., Ltd.) was added thereto.
26.6% by weight of added polyester polyol to which 4% by weight was added (PCL220N: manufactured by Daicel Chemical Industries, Ltd.)
And ionic conductive agent (lithium perchlorate) 0.5% by weight
Was mixed with 4.5% by weight of an ether-based polymer (PPG2000: manufactured by Sanyo Chemical Industries, Ltd.) to which a conductive blade was added.

Comparative Example 4 Table 1 shows the composition of Comparative Example 4.

For comparison, as shown in the following formulation, 67 parts by weight of a polyester polyol (PCL220N: manufactured by Daicel Chemical Co., Ltd.) was heated and dissolved, and carbon black (Toka Black # 5500: manufactured by Tokai Carbon Co., Ltd.) was added thereto.
4% by weight of a polyester polymer (P-20)
10: 26.6% by weight of Kuraray Co., Ltd. and 4.5% by weight of an ether-based polymer (PPG2000: Sanyo Kasei Co., Ltd.) to which 0.5% by weight of an ionic conductive agent (lithium perchlorate) was added. A conductive blade was formed in the same manner as in Example 1 except for the above.

Comparative Example 5 Table 1 shows the composition of Comparative Example 5.

For comparison, an ester polymer having a high crystallinity other than caprolactone (V-200) was used as a polymer base material.
0MM: manufactured by Sumitomo Bayer Urethane Co., Ltd.), and a blade of Comparative Example 5 was manufactured in the same manner as in Example 5 described above.

(Test Example 1) The blades of Examples 1 to 5 and Comparative Examples 1 to 5 were attached to a commercially available laser printer, and the number of sheets passed until the blades were worn was compared. The results are also shown in Table 1.

The blades of Example 5 and Comparative Examples 1 and 5 were held in an environment of saturated steam at 70 ° C., and the rubber hardness (Hs: JIS A) and the rebound resilience (%) were set at the initial value and at 1%.
The measurement was performed every week, and the change over time in the physical properties was measured. The results are shown in FIG.

[0094]

[Table 1]

The conductive member of the present invention can obtain excellent abrasion resistance and hydrolysis resistance by using a caprolactone polyurethane among ester polyurethanes as the polymer base material. In addition, as shown in FIG. 7, by using a caprolactone-based polyurethane for the polymer base material, the properties of the hardness and the rebound resilience are less reduced. Further, the polymer to be blended with the polymer base material is an ester-based polymer and an ether-based polymer, and the blending amount of the polymer is 30% by weight or less for the ester-based polymer and 1% by weight or less for the ether-based polymer, so that the abrasion resistance is reduced. It does not lower the properties and hydrolysis resistance.

Further, with the conductive blade formed of such a conductive member, the blade characteristics can be improved.

[Brief description of the drawings]

FIG. 1 is a diagram showing an example of the shape of a conductive member of the present invention.

FIG. 2 is a diagram showing an example of a conductive member manufacturing apparatus of the present invention.

FIG. 3 is a diagram for explaining a function of a conductive member of the present invention.

FIG. 4 is a diagram showing an example of a usage mode of the conductive member of the present invention.

FIG. 5 is a diagram showing an example of a usage mode of the conductive member of the present invention.

FIG. 6 is a diagram showing an example of a usage mode of the conductive member of the present invention.

FIG. 7 is a graph showing changes over time in hardness and rebound resilience of blades of Examples and Comparative Examples of the present invention.

[Explanation of symbols]

 1, 31 Photoconductor 10A to 10D, 30, 30A to 30C Conductive member 11A to 11D Conductive section 12A to 12D Non-conductive section 32 Transfer belt 33, 33A, 33B Transfer roller 34 Intermediate transfer body 35 Transfer material 36 Developing device 37 Transfer material Conveying means 38 Transfer material roller 39 Fixing means 41 Toner container 42 Toner feed roll

Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat II (reference) F16C 13/00 F16C 13/00 E 3J103 G03G 15/02 101 G03G 15/02 101 4F071 15/08 504 15/08 504B 4J002 15/16 15/16 5G301 21/10 H01B 1/24 Z 21/06 (C08L 75/06 H01B 1/24 75:08) // (C08L 75/06 G03G 21/00 318 75:08) 340 F-term (Ref.) HA31 HA44 HA45 HA48 HA52 HA60 4F071 AA53 AB03 AB13 AE15 AF22 AF57 AH12 BA02 BB12 BB13 BC07 4J002 CK031 CK032 DA036 DD057 FD116 FD117 GQ00 5G301 DA18 DA53 DA59 DD05 DD10

Claims (10)

[Claims] 1. A conductive member used in contact with an object to be contacted, wherein the conductive member has a simple structure made of a polymer base material containing an electrically conductive agent, and the distribution of the conductive agent near a contact portion with the object to be contacted. A conductive member having a density smaller than that of other parts or substantially zero, and wherein the polymer substrate is made of at least one kind of polyurethane selected from ester-based polyurethane. 2. The conductive member according to claim 1, wherein the polyurethane is a caprolactone-based polyurethane. 3. The method according to claim 2, wherein the polymer substrate is
A conductive member comprising a polyurethane in which an ether-based polymer is blended in an amount of 1% by weight or less with a caprolactone-based polyurethane. 4. The method according to claim 2, wherein the polymer substrate is
A conductive member comprising a polyurethane in which a caprolactone-based polyurethane is blended with 30% by weight or less of another ester-based polymer. 5. The polymer according to claim 1, wherein the raw material polymer for forming the polymer base material has a molecular weight of 1,000.
A conductive member having a size of from 4,000 to 4,000. 6. The range according to claim 1, wherein the distribution density of the conductive agent is smaller than or substantially zero in other parts of the conductive agent from the contact end with the contacted body.
A conductive member having a range of up to 120 μm. 7. The conductive member according to claim 1, wherein the true density of the particles of the conductive agent or the specific gravity of the particles containing the conductive agent is larger than the specific gravity of the polymer base material. . 8. The conductive member according to claim 7, wherein the polymer base material containing the conductive agent is manufactured by centrifugal molding. 9. The conductive member according to claim 1, wherein the conductive agent of the conductive member contains at least carbon black. 10. The conductive member according to claim 1, wherein the conductive agent of the conductive member includes at least carbon black as a main component, and further includes at least one selected from the group consisting of an ionic conductive agent and a carbon black dispersant. A conductive member comprising one kind.