JP6905418B2 - Conductive members for electrophotographic, process cartridges and electrophotographic equipment - Google Patents

Description

The present invention relates to conductive members for electrophotographic, process cartridges and electrophotographic apparatus.

A conductive member for electrophotographic such as a charging member is used in the electrophotographic image forming apparatus (hereinafter, also referred to as “electrophotograph apparatus”). A charged member for contacting a charged body such as an electrophotographic photosensitive member to charge the surface of the charged member is required to be stably charged for a long period of time.
Patent Document 1 discloses a charging member in which charging defects and a decrease in charging ability due to surface contamination are unlikely to occur even when repeatedly used for a long period of time. Specifically, a charging member having a convex portion derived from conductive resin particles provided on the surface layer of the charging member is disclosed.
Further, Patent Document 2 discloses a charging roll having a surface free energy of a conductive coating member of 30 mN / m or more and having a layer of organic fine particles or inorganic fine particles having a particle size of 3.0 μm or less on the entire surface thereof. ing.

Japanese Unexamined Patent Publication No. 2008-276026 Japanese Unexamined Patent Publication No. 2006-91495

One aspect of the present invention is to provide a conductive member for electrophotographic capable of maintaining a stable charging ability even when the electrophotographic apparatus is used for a long period of time.
Another aspect of the present invention is to provide a process cartridge and an electrophotographic apparatus capable of stably forming a high-quality electrophotographic image.

According to one aspect of the present invention, the conductive member for electrophotographic having a conductive support and a surface layer formed on the conductive support.
The surface layer has a three-dimensionally continuous skeleton and has pores communicating in the thickness direction.
A through hole is included when an arbitrary 150 μm square region on the surface of the surface layer is photographed and the region is divided into 60 equal parts vertically and 60 equal parts horizontally and equally divided into 3,600 squares. The number of squares is 100 or less,
The skeleton is non-conductive and
The skeleton is composed of a plurality of resin particles bonded to each other via a neck.
The resin particles contain a radiation-disintegrating type resin, and the average value D1 of the equivalent circle diameters of the resin particles is 0.1 μm or more and 20 μm or less.
Provided is a conductive member for electrophotographic feature.

Further, according to another aspect of the present invention.
A conductive member for electrophotographic having a conductive support, an intermediate layer, and a surface layer in this order.
The surface layer has a three-dimensionally continuous skeleton and has pores communicating in the thickness direction.
A through hole is included when an arbitrary 150 μm square region on the surface of the surface layer is photographed and the region is divided into 60 equal parts vertically and 60 equal parts horizontally and equally divided into 3,600 squares. The number of squares is 100 or less,
The skeleton is non-conductive and
The skeleton is composed of a plurality of resin particles bonded to each other via a neck.
The average value D1 of the equivalent circle diameters of the resin particles is 0.1 μm or more and 20 μm or less, and
Provided is a conductive member for electrophotographic, wherein the intermediate layer contains a radiation-disintegrating type resin and is non-conductive.

According to another aspect of the present invention, there is provided a process cartridge that is detachably configured on the main body of the electrophotographic apparatus and includes the above-mentioned conductive member.
According to still another aspect of the present invention, an electrophotographic apparatus including the above-mentioned conductive member is provided.

According to one aspect of the present invention, it is possible to provide a conductive member capable of achieving both suppression of abnormal discharge and suppression of image defects due to stain adhesion. Further, according to another aspect of the present invention, it is possible to provide a process cartridge and an electrophotographic apparatus capable of suppressing a whiteout image for a long period of time and suppressing an image defect due to stain adhesion.

It is explanatory drawing of the principle that dirt adheres to the surface of a charged member electrostatically. It is explanatory drawing of the principle that electric charge is accumulated in the surface layer of a charged member. It is sectional drawing which shows an example of a roller-shaped conductive member. It is sectional drawing which shows an example of the roller-shaped conductive member which has an intermediate layer. It is explanatory drawing of a neck. It is a figure which shows an example of the separating member. It is sectional drawing of the process cartridge which concerns on one aspect of this invention. It is sectional drawing of the electrophotographic image forming apparatus which concerns on one aspect of this invention. It is the schematic of the coating apparatus which coats particles and forms a surface layer. It is a schematic diagram of a corona charger.

The present inventors examined the charging members according to Patent Document 1 and Patent Document 2, and confirmed that they have an effect of suppressing adhesion of toner and an external additive.
However, in recent years, with the increase in definition of electrophotographic images, the charging voltage applied between the charging member and the charged body tends to increase. That is, by increasing the charging voltage, the development contrast can be increased, and as a result, the color gradation can be increased. However, when the charging voltage is increased, an abnormal discharge in which the amount of discharge charge locally increases tends to occur. In a low temperature and low humidity environment, abnormal discharge is particularly likely to occur.

The discharge from the charged member to the charged member is generated according to Paschen's law. Further, the discharge phenomenon can be explained as a diffusion phenomenon of an electron avalanche in which ionized electrons collide with molecules and electrodes in the air and repeatedly generate electrons and cations while increasing exponentially. This electron avalanche diffuses according to the electric field, and the degree of this diffusion determines the final amount of discharge charge.
Further, the abnormal discharge occurs when a voltage exceeding Paschen's law is applied and the electron avalanche is greatly diffused to have a very large amount of discharge charge. It can be actually observed using a high-speed camera and an image intensifier, and its size is about 200 μm to 700 μm. When the discharge current amount is measured, the discharge current amount of normal discharge is measured. It will be about 100 times or more. Therefore, in order to suppress abnormal discharge, it is considered that the amount of discharge charge generated by the diffusion of electron avalanche should be suppressed within a normal range under the condition that the applied voltage is large.

Next, the adhesion of electrostatic stains to the surface of the charging member will be described. Ions of the opposite polarity to the charging voltage adhere to the surface and deposits of the charging member due to discharge. Therefore, the electrostatic adhesive force increases as the electric discharge is received. In particular, in a low-temperature and low-humidity environment, it is difficult for the charge of dirt to be canceled by the moisture in the air. Therefore, the toner and the external additive are more likely to adhere to the surface of the charging member.

Hereinafter, with reference to FIG. 1, a charging device for charging the surface of the charging member with a negative polarity will be taken as an example, and the adhesion of electrostatic stains to the surface of the charging member will be specifically described.
The charging member 10 is connected to the power supply 13 and faces the photosensitive drum 11 grounded to the ground 14. An electric discharge is generated in the gap between the charging member 10 and the photosensitive drum 11, and negative-polarity electrons are attracted to the photosensitive drum 11 and positive-polarity ions are attracted to the surface of the charging member 10 according to the electric field. At this time, if dirt 12 such as toner is present on the surface of the charging member 10, positively polar ions attracted to the charging member 10 adhere to the dirt 12, and the dirt 12 is positively charged. As a result, the electrostatic attraction between the negatively charged charging member 10 and the dirt 12 increases, and the dirt 12 strongly adheres to the surface of the charging member 10. Further, since this phenomenon repeatedly occurs with the progress of use, the adhesive force of the dirt 12 increases.

Then, the present inventors are less likely to cause an abnormal discharge even when the charging voltage is increased, and a charging member capable of effectively suppressing electrostatic adhesion of stains such as toner to the surface for a long period of time. We repeated the examination to obtain. As a result, it was found that the conductive member according to the first aspect described below and the conductive member according to the second aspect described below well satisfy the above requirements.

<First aspect>
It has a conductive support and a surface layer formed on the conductive support.
The surface layer has a three-dimensionally continuous skeleton and has pores communicating in the thickness direction.
A through hole is included when an arbitrary 150 μm square region on the surface of the surface layer is photographed and the region is divided into 60 equal parts vertically and 60 equal parts horizontally and equally divided into 3,600 squares. The number of squares is 100 or less,
The skeleton is non-conductive and
The skeleton is composed of a plurality of resin particles bonded to each other via a neck.
A conductive member for electrophotographic in which the resin particles contain a radiation-disintegrating type resin and the average value D1 of the equivalent circle diameters of the resin particles is 0.1 μm or more and 20 μm or less.

<Second aspect>
It has a conductive support, an intermediate layer and a surface layer in this order.
The surface layer has a three-dimensionally continuous skeleton and has pores communicating in the thickness direction.
A through hole is included when an arbitrary 150 μm square region on the surface of the surface layer is photographed and the region is divided into 60 equal parts vertically and 60 equal parts horizontally and equally divided into 3,600 squares. The number of squares is 100 or less,
The skeleton is non-conductive and
The skeleton is composed of a plurality of resin particles bonded to each other via a neck.
The average value D1 of the equivalent circle diameters of the resin particles is 0.1 μm or more and 20 μm or less, and
The intermediate layer is a conductive member for electrophotographic, which contains a radiation-disintegrating type resin and is non-conductive.

(Suppression of abnormal discharge)
As described above, the abnormal discharge has a size of approximately 200 μm to 700 μm. This size is the result of a normal discharge growing in space according to an electric field. That is, in order to suppress the abnormal discharge, the growth of the normal discharge may be suppressed. The normal discharge can be confirmed with a high-speed camera and an image intensifier in the same manner as the abnormal discharge, and its size is 30 μm or less.

The surface layer according to the present invention has a three-dimensionally continuous skeleton, and an arbitrary 150 μm square region on the surface of the surface layer is photographed, and the region is divided into 60 equal parts vertically and 60 equal parts horizontally. When divided into 3600 squares equally, the number of squares including through holes is 100 or less. It is considered that this spatially limits the diffusion of electron avalanches and suppresses the growth of normal discharge to the size of abnormal discharge. That is, although the surface layer has pores communicating in the thickness direction, the number of through holes penetrating in the same direction as the electric field is small. Therefore, it is considered that the discharge from the surface of the conductive support is divided, which limits the increase in the size of the normal discharge.

As a result of directly observing the electric discharge generated between the conductive member for electrophotographic and the photosensitive drum according to the present invention using a high-sensitivity camera, when a surface layer which is a porous body is present on the surface of the conductive member, It has been confirmed that a single discharge is subdivided. From this, it is considered that the above estimation mechanism is correct.

(Stain control)
Next, the suppression of dirt adhesion will be described. First, dirt adheres to the surface of the conductive member by physical adhesive force or electrostatic attraction. In particular, the dirt that rushes into the charging member has a charge distribution from plus to minus, so electrostatic adhesion of dirt is unavoidable. Further, as described above, in the conventional conductive member, ions having a polarity opposite to the applied voltage are attached to the surface and deposits of the charged member due to the discharge, so that the electrostatic adhesive force is applied as the discharge is received. Is only increasing, and it is difficult to expect the peeling of dirt once attached.

The conductive member according to this embodiment can suppress the adhesion of physical stains and the adhesion of electrostatic stains.
First, regarding physical adhesion, since the surface layer is a porous body having a fine skeleton and pores, the contact point can be made very small, and physical adhesion of dirt can be suppressed.

Next, the suppression of electrostatic adhesion will be described with reference to FIG.
FIG. 2 is a schematic view of the charging member 21 and the photosensitive drum 22 in the case of negative charging. When a discharge occurs, the negative charge 24 advances to the surface of the photosensitive drum according to the electric field, and the positive charge 23 advances to the surface layer 20. At this time, since the surface layer 20 is non-conductive, the positive polarity charge 23 is captured and the surface layer 20 is positively charged up. At this time, since it electrostatically repels the positively charged dirt that tends to adhere to the surface of the charged member due to the electric field, the electrostatic attraction acting on the dirt can be reduced. That is, it is possible to reduce electrostatic adhesion that could not be suppressed at all in the past.

Further, even if dirt adheres to the surface of the surface layer 20, since the surface layer 20 is a porous body, the dirt that has been electrostatically adhered can be discharged. Specifically, when the electric discharge inside the porous body generated in the pores is applied to the dirt adhering to the surface of the surface layer, the polarity of the dirt can be changed negatively, so that the electrostatics acting on the dirt The direction of the attractive force is reversed, and the dirt is peeled off by the electric field.
That is, since physical adhesion and electrostatic adhesion of stains can be suppressed very efficiently at the same time, it is expected that image defects due to stain adhesion can be reduced.

(Non-conductive intermediate layer)
The following means are also effective in suppressing the leakage of accumulated charges. That is, with respect to the conductive member having the conductive support, the intermediate layer, and the surface layer in this order, the intermediate layer is non-conductive and contains a radiation decay type resin. As a result, the resistance of the surface layer is lowered, and even in a state where the accumulated charge is likely to leak, the intermediate layer containing the radiation decay type resin suppresses oxidation due to discharge and generation of by-products. , The resistance of the intermediate layer is not lowered. Since the intermediate layer can maintain non-conductive property, leakage of accumulated charges from the surface layer to the conductive support is suppressed. As a result, the accumulated charge on the surface layer can be maintained, so that the dirt adhesion suppressing effect can be maintained for a long period of time.

<First Embodiment>
Hereinafter, the conductive member according to the first aspect will be described with reference to the drawings. However, the present invention is not limited to the following embodiments. Hereinafter, the conductive member for electrophotographic will be described with reference to a charging member which is a typical example thereof, but the use of the conductive member for electrophotographic according to this embodiment is not limited to the charging member. do not have.

(Example of member configuration)
3 (a) and 3 (b) show cross-sectional views of an example of a roller-shaped conductive member according to the present invention. This conductive member includes a conductive support and a surface layer formed on the outside of the conductive support, and the surface layer is a porous body. The skeleton of the surface layer is composed of a plurality of resin particles, and the resin particles include a radiation-disintegrating type resin.
The conductive member shown in FIG. 3A is composed of a conductive support and a surface layer 31. The conductive support is made of a core metal 32 as a conductive shaft core (base). The surface layer 31 is formed on the outer periphery of the conductive support.

The conductive member shown in FIG. 3B is also composed of a conductive support and a surface layer 31. The conductive support of FIG. 3B is composed of a core metal 32 as a conductive shaft core (base) and a conductive resin layer 33 provided on the outer periphery thereof. The surface layer 31 is formed on the outer periphery of the conductive resin layer 33. If necessary, the conductive member may have a multi-layer structure in which a plurality of the conductive resin layers 33 are arranged as long as the effects of the present invention are not alienated. Further, the conductive member is not limited to the roller shape, and may be, for example, a blade shape.

4 (a) and 4 (b) show cross-sectional views of an example of a roller-shaped conductive member having an intermediate layer containing a radiation-disintegrating resin according to the present invention. This conductive member includes a conductive support, an intermediate layer, and a surface layer, and the surface layer is a porous body.
The conductive member shown in FIG. 4A is composed of a conductive support, an intermediate layer 43, and a surface layer 41. The conductive support is made of a core metal 42 as a conductive shaft core. The intermediate layer 43 is formed on the outside of the conductive support and contains a radiation decay type resin. The surface layer 41 is formed on the outer periphery of the intermediate layer 43.

The conductive member shown in FIG. 4B is composed of a conductive support, an intermediate layer 43, and a surface layer 41. The conductive support includes a core metal 42 as a conductive shaft core body and a conductive resin layer 44 provided on the outer periphery thereof. The intermediate layer 43 contains a radiation decay type resin. The surface layer 41 is formed on the outer periphery of the intermediate layer 43. If necessary, the conductive member may have a multi-layer structure in which a plurality of the conductive resin layers 44 are arranged as long as the effects of the present invention are not alienated. Further, the conductive member is not limited to the roller shape, and may be, for example, a blade shape.

[Conductive shaft core]
As the conductive shaft core body, one appropriately selected from those known in the field of conductive members for electrophotographic can be used. For example, a cylinder in which the surface of a carbon steel alloy is nickel-plated with a thickness of about 5 μm can be used. A metal shaft core is preferred. When the energy at the time of discharge is partially converted into thermal energy, the metal shaft core with high thermal conductivity easily releases the thermal energy, the damage to the conductive member is reduced, and the durability is increased. ..

[Conductive resin layer]
As a material constituting the conductive resin layer, a rubber material, a resin material, or the like can be used. The rubber material is not particularly limited, and rubber known in the field of conductive members for electrophotographic can be used, and specific examples thereof include the following. Epichlorohydrin homopolymer, epichlorohydrin-ethylene oxide copolymer, epichlorohydrin-ethylene oxide-allyl glycidyl ether ternary copolymer, acrylonitrile-butadiene copolymer, hydrogenated product of acrylonitrile-butadiene copolymer, silicone rubber, acrylic rubber and Urethane rubber, etc. As the resin material, a resin known in the field of conductive members for electrophotographic can be used. Specific examples thereof include polyurethane resin, polyamide resin, polyester resin, polyolefin resin, epoxy resin, and silicone resin.

Of these, acrylonitrile-based rubber is preferable. This is because, in the case of acrylonitrile-based rubber, even when energy is applied during discharge, the reactivity with the surface layer of the present invention is poor, and by-products are less likely to be generated and the discharge deterioration accompanying the discharge is unlikely to occur.
An electronic conductivity-imparting agent or an ionic conductivity-imparting agent can be added to the rubber forming the conductive resin layer, if necessary, in order to adjust the electric resistance value. Examples of the electron conductivity-imparting agent include carbon black and graphite exhibiting electron conductivity; oxides such as tin oxide; metals such as copper and silver; conductivity obtained by coating the surface of particles with oxides and metals. Sex particles can be mentioned. Examples of the ion conductivity-imparting agent include an ion conductivity-imparting agent having an ion exchange performance such as a quaternary ammonium salt exhibiting ion conductivity and a sulfonate.

Further, as long as the effects of the present invention are not impaired, fillers, softeners, processing aids, tackifiers, anti-tacking agents, dispersants, foaming agents, and roughening agents generally used as resin compounding agents are used. Particles and the like can be added.
As a guideline for the electric resistance value of the conductive resin layer, the volume resistivity is 1 × 10 ³ Ω · cm or more and 1 × 10 ⁹ Ω · cm or less. It has been confirmed that the surface layer according to the present invention can suppress image adverse effects caused by excessive discharge even when the electric resistance value of the conductive support is sufficiently low.

<Surface layer>
The surface layer has a three-dimensionally continuous skeleton and has pores that communicate with each other in the thickness direction. A through hole is included when an arbitrary 150 μm square region on the surface of the surface layer is photographed and the region is divided into 60 equal parts vertically and 60 equal parts horizontally and equally divided into 3,600 squares. The number of squares is 100 or less. The skeleton is non-conductive, and the skeleton is composed of a plurality of particles bonded to each other via a neck. The average value D1 of the equivalent circle diameters of the particles is 0.1 μm or more and 20 μm or less.

[(1) Three-dimensionally continuous skeleton and pores communicating in the thickness direction]
The surface layer has a three-dimensionally continuous skeleton. Here, the three-dimensionally continuous skeleton means a skeleton having a plurality of branches and having a plurality of locations connected from the surface of the conductive member to the surface of the conductive support.
In addition, the surface layer has pores that communicate in the thickness direction in order to transport the discharge generated in the skeleton to the surface of the photosensitive drum. Here, the pores communicating in the thickness direction refer to pores reaching from an opening having a surface to the surface of the conductive support. Further, it is preferable that the pores connect a plurality of openings on the surface of the surface layer and have a plurality of branches. In this way, the pores connecting the plurality of openings and having the plurality of branches can more reliably disperse the electron avalanche in the surface layer.
Further, the communicating pores ensure a discharge path from the surface of the conductive support to the surface of the surface layer. Therefore, the conductive member according to the present embodiment provided with the non-conductive surface layer can perform the electric discharge necessary for forming the electrophotographic image as the charging member.

Here, since the discharge diffuses in a conical shape according to the direction of the electric field, if a thick and linear hole exists in the direction of the electric field, the discharge may grow to an abnormal discharge and a white-out image may occur. Therefore, it is preferable that the holes, that is, the through holes, which are linearly arranged in the same direction as the electric field, that is, in the thickness direction, are as small as possible and fine.

The fact that the skeleton of the surface layer is three-dimensionally continuous and the pores communicate in the thickness direction means that the SEM image obtained by a scanning electron microscope (SEM), a three-dimensional transmission electron microscope, and X-ray CT It can be confirmed in a three-dimensional image of a porous body obtained by an inspection device or the like. That is, in the SEM image or the three-dimensional image, the skeleton may have a plurality of branches, and there may be a plurality of locations where the surface of the surface layer is connected to the surface of the conductive support. Further, it may be confirmed that the pores connect the plurality of openings on the surface of the surface layer, have a plurality of branches, and reach the surface of the conductive support from the surface of the surface layer. ..

[(2) Uniformity through hole]
The surface layer needs to have a uniform structure in order to suppress image defects caused by the structure of the porous body. As described above, the presence of a linear through hole in the direction of the electric field makes it easier for the discharge to grow into an abnormal discharge. Further, even if it is a minute through hole, the degree of division of the electron avalanche is different from that of the place without the through hole, and the uniformity of discharge may be reduced. Therefore, it is necessary to limit the through holes of the surface layer to the following range. Here, the through hole is a hole that is linearly connected so that the surface of the conductive support can be directly observed when facing the surface of the surface layer. These through holes include those branched inside the surface layer, but it is judged by whether or not the surface of the conductive support can be directly observed.

Specifically, when an arbitrary 150 μm square region on the surface of the surface layer is photographed and the region is divided into 60 equal parts vertically and 60 equal parts horizontally and equally divided into 3,600 square groups. , The number of square groups including through holes needs to be 100 or less. By reducing the number of square groups including the through holes to 100 or less, it is possible to prevent the through holes from appearing as defects in the surface layer in an image defect.
Since the effect of suppressing the diffusion of the discharge and suppressing the abnormal discharge is increased, it is more preferable that the number of square groups including the through holes is 25 or less. The lower limit of the number of square groups including the through hole is not particularly limited, and a smaller value is preferable.

The through holes in the surface layer can be confirmed as follows. First, the surface layer is observed from the direction facing the surface layer, and an arbitrary 150 μm square region on the surface of the surface layer is photographed. At this time, a method capable of observing a region of 150 μm square, such as a laser microscope, an optical microscope, or an electron microscope, may be appropriately used.
Next, when the region is divided vertically into 60 equal parts and horizontally into 60 equal parts into a group of 3,600 squares, the number of squares including the through holes may be counted.

[(3) Non-conductive]
The skeleton of the surface layer needs to be non-conductive. Non-conductive means that the volume resistivity is 1 × 10 ¹⁰ Ω · cm or more. Since the surface layer is non-conductive, the skeleton of the surface layer can capture and charge up ions having a polarity opposite to the charging voltage by electric discharge. When the surface layer is charged up, the adhesion of dirt is reduced by electrostatic repulsion, and the attached dirt is irradiated with electric discharge in the pores, so that the charge of the dirt can be reversed and peeled off. It becomes.

The volume resistivity of the skeleton of the surface layer is preferably 1 × 10 ¹² Ω · cm or more and 1 × 10 ¹⁷ Ω · cm or less. By setting the volume resistivity to 1 × 10 ¹² Ω · cm or more, the skeleton begins to charge up and the adhesion of dirt can be suppressed. On the other hand, by setting the volume resistivity to 1 × 10 ¹⁷ Ω · cm or less, the generation of electric discharge in the pores of the surface layer is promoted, and the dirt can be electrostatically peeled off. Furthermore, when the volume resistivity is 1 × 10 ¹⁵ Ω ・ cm or more and 1 × 10 ¹⁷ Ω ・ cm or less, the influence of the variation in charge-up of the surface layer can be reduced, and the electrostatic peeling of dirt is further enhanced. It is more preferable because it can be promoted.

The method for measuring the volume resistivity of the surface layer is as follows. First, a region not containing pores is taken out from the surface layer existing on the surface of the conductive member as a test piece using tweezers. Next, the cantilever of the scanning probe microscope (SPM) is brought into contact with the cantilever, and the test piece is sandwiched between the cantilever and the conductive substrate to measure the volume resistivity. The longitudinal direction of the conductive member is divided into 10 equal parts, the volume resistivity is measured at any one location (10 locations in total) in each of the obtained 10 regions, and the average value is the volume resistivity of the surface layer. And.

[(4) Neck]
The skeleton of the surface layer needs to consist of multiple particles bonded to each other through a neck. Here, the neck is a gentle curved surface without discontinuities formed by mass transfer of the constituent substances of the particles, and is a one-leaf hyperboloidal (drum-shaped) constricted portion.
FIG. 5 is a diagram schematically showing a part of the skeleton of the surface layer manufactured by using spherical particles as an example of the skeleton of the surface layer in two dimensions. In FIG. 5, the particles 51 are bonded via the neck 52. Although the neck 52 is represented as a straight line in FIG. 5, it actually shows a cross section cut by the broken line shown in FIG.

5 (a) to 5 (c) show the cut surface of the plurality of bonded particles, and FIG. 5 (d) shows the cut surface of the neck portion. For easy illustration, the description is made with spherical particles, but the same explanation can be made with non-spherical particles.
5 (a) and 5 (b) show a cut surface parallel to the surface of the conductive support 50, and FIGS. 5 (c) and 5 (d) show a cut surface perpendicular to the surface of the conductive support 50. Show the surface.
5 (a) and 5 (b) show cross-sectional views taken from the direction of arrow 58 shown in FIGS. 5 (c) and 5 (d). FIG. 5 (c) shows a cross-sectional view seen from the direction of arrow 501 shown in FIG. 5 (d). FIG. 5D shows a cross-sectional view seen from the direction of arrow 59 shown in FIG. 5C.

The cut surface 53 shown by the solid line in FIG. 5 (a) is a cut surface obtained by cutting on the surface 56 shown in FIG. 5 (c). The cut surface 54 shown by the solid line in FIG. 5 (b) is a cut surface obtained by cutting on the surface 57 shown in FIG. 5 (c), and the two-dot broken line 55 shown in FIG. 5 (b) is shown in FIG. Corresponds to the cut surface 53 shown by the solid line in (a). As shown in FIGS. 5A to 5C, the area of the cut surface changes depending on the height of the surface for cutting the skeleton of the surface layer from the surface of the conductive support 50, and the neck appearing on the cut surface. The length of 52 also changes. Specifically, the neck 52a shown in FIG. 5A is longer than the neck 52b shown in FIG. 5B.
By three-dimensionally connecting a plurality of particles via the neck, the walls forming the pores have irregularities, and the shape of the pores becomes more complicated. As a result, the effect of suppressing the diffusion of electron avalanches can be further enhanced, and the effect of suppressing the occurrence of abnormal discharge can be further enhanced.

Further, when the particles are bonded to each other via the neck, the electrical interface between the particles disappears, and the skeleton constituting the surface layer functions as one dielectric. Since the skeleton functions as a single dielectric, it is possible to suppress partial variation in the amount of accumulated charge, and it is possible to form a uniform discharge over the entire surface layer.
Further, it is considered that the unevenness of the wall surface of the pores tends to give an opportunity for discharge. That is, the pores having a complicated shape due to the neck can increase the probability of occurrence of discharge in the pores and increase the amount of charge accumulated. As a result, the effect of reducing the adhesion of dirt to the surface of the charged member and promoting peeling can be increased.

In addition, the resin particles are bonded to each other at the neck to form an integrated state without an interface, so that when the particles are discharged, a chain reaction due to radicals generated in the chemical structure is likely to occur. Since the radicals of the radiation decay type resin are unstable, the probability that the radicals cause main chain breakage can be improved by facilitating the chain reaction. As a result, oxidation and by-products are generated, and the phenomenon that the surface layer becomes low in resistance can be suppressed.

It should be noted that the confirmation that the particles are bonded to each other via the neck can be confirmed by observing the bonded portion of the particles with a three-dimensional image obtained by measurement by X-ray CT, a laser microscope, an optical microscope, an electron microscope, or the like. good. At this time, the skeleton and the neck may be photographed to confirm that the joint portion of the particles is a gentle curved surface without discontinuities and is constricted in a single-leaf hyperboloid shape (drum shape).
In addition, as another method for confirming the neck, the bonded particles can be decomposed by breaking the surface layer with tweezers. Further observation of the decomposed and separated particles confirms that the particles were bonded to each other, and that the particles were bonded to each other through the neck.

[Particle shape]
The shape of the particles for forming the skeleton of the surface layer need only be able to form pores that communicate with the skeleton that is three-dimensionally continuous in the thickness direction, and the shape is a polyhedron such as a sphere, an ellipsoid, or a cube, or a semicircle. It can have a body or any shape. Among them, particles having a complicated shape formed by crushing, crushing, etc. are preferable because the surface area can be increased and the charge-up of the surface layer can be increased. Furthermore, since the surface shape of the surface layer has irregularities, even if very fine irregularities are formed on the surface by molecular cutting of the radioactive decay type resin, the amount of change in the total surface area is very small. It is possible to suppress changes in function due to changes.

As for the shape of the particles, the joint portion of the particles may be observed with a three-dimensional image obtained by measurement by X-ray CT, a laser microscope, an optical microscope, an electron microscope, or the like. At this time, the skeleton and the neck may be photographed, and the shape of the particles cut by the neck may be visually confirmed in the image processing to obtain the particle shape.
Further, as another method for confirming the particle shape, the bonded particles can be decomposed by breaking the surface layer with tweezers. It can be confirmed by further observing the particles that have decomposed and separated.

[Average value D1 of the equivalent circle diameter of particles]
The average value D1 of the equivalent circle diameters of the particles forming the skeleton of the surface layer needs to be 0.1 μm or more and 20 μm or less. When it is 0.1 μm or more, pores are appropriately formed and discharge in the surface layer can be promoted, so that dirt can be peeled off. By setting the thickness to 20 μm or less, image defects due to the non-conductive structure can be suppressed. More preferably, it is 0.1 μm or more and 6.0 μm or less. By setting the thickness to 6.0 μm or less, it is possible to reduce stains stuck in the pores on the surface of the surface layer and suppress image defects due to stain adhesion.

The average value D1 of the equivalent circle diameters of the particles may be determined by observing the bonding portion of the particles with a three-dimensional image obtained by measurement by X-ray CT, a laser microscope, an optical microscope, an electron microscope, or the like. In particular, measurement by X-ray CT is preferable because the surface layer can be measured three-dimensionally. For example, an X-ray CT inspection device (trade name: TOHKEN-SkyScan2011 (radioactive source: TX-300), manufactured by Mars Tohken X-ray Inspection Co., Ltd.) is used to take slice images of the skeleton and neck. Then, the obtained slice image may be measured by image processing software such as Image-pro plus (product name, manufactured by Media Cybernetics).

Specifically, the obtained slice image is used for two particles bonded through a certain neck. The length of the neck included in the cut surface among the plurality of cut surfaces parallel to the surface of the conductive support, which is a cross section perpendicular to the neck cross section as shown in FIGS. 5 (a) or 5 (b). Find the cut surface with the longest length and binarize it by the Otsu method. Next, for example, a watershed process is performed to create a neck connecting the most recessed portions of the contour line. Next, the center of gravity of the particles cut by this neck may be calculated, and the radius of the circumscribed circle centered on this center of gravity and in contact with the boundary line of the particles may be measured as the equivalent circle diameter of the particles. This is divided into 10 equal parts in the longitudinal direction of the conductive member, and the equivalent circle diameter of the particles is measured in any 50 particles (500 in total) in an arbitrary image in each region of the obtained 10 regions. Then, the arithmetic mean value (hereinafter, also referred to as “average value”) is defined as the average value D1 of the equivalent circle diameters of the particles.

Further, as another method for confirming the particle shape, the bonded particles can be decomposed by breaking the surface layer with tweezers. Then, on the surface of the conductive support, an image of the decomposed and separated particles may be acquired by a laser microscope, an optical microscope, an electron microscope, or the like, and the average value D1 of the equivalent circle diameter may be measured by the same method as described above. ..

[Ratio of the equivalent circle diameter of the neck cross section to the equivalent circle diameter of the particles]
The average value D2 of the equivalent circle diameter of the cross section of the neck for forming the skeleton of the surface layer is preferably 0.1 times or more and 0.7 times or less the average value D1 of the equivalent circle diameter of the particles. When it is 0.1 times or more, the discharge space can be divided and the effect of suppressing abnormal discharge can be produced. By making it 0.7 times or less, the electric field in the pores becomes a complicated and complicated distribution, the probability that a discharge occurs in the pores increases, and the discharge charge in the pores increases, resulting in dirt. The effect of peeling and the improvement of image quality can be obtained.

[Average value D2 of the equivalent circle diameter of the neck cross section]
The equivalent circle diameter of the cross section of the neck may be measured by observing the joint portion of the particles with a three-dimensional image obtained by measurement by X-ray CT, a laser microscope, an optical microscope, an electron microscope, or the like. In particular, measurement by X-ray CT is preferable because the surface layer can be measured three-dimensionally.
Specifically, for two particles bonded via a certain neck, a cross-sectional image of the neck 52 as shown in FIG. 5D is created by using the slice image obtained by the X-ray CT. It is binarized by the Otsu method. Next, the center of gravity of the neck cross section may be calculated, and the radius of the circumscribed circle tangent to the boundary line of the neck cross section may be measured as the equivalent circle diameter of the neck cross section. This is divided into 10 equal parts in the longitudinal direction of the conductive member, and in any 20 particles (200 in total) in any image in each region of the obtained 10 regions, the equivalent circle diameter of the cross section of the neck. Is measured, and the average value D2 is calculated.

As another method for measuring the equivalent circle diameter of the neck cross section, the bonded particles can be decomposed by breaking the surface layer with tweezers. Then, an image of the particles decomposed and separated on the surface of the conductive support may be obtained, and the circle-equivalent diameter of the particles and the circle-equivalent diameter of the joint portion corresponding to the cross section of the neck may be measured.

[Thickness of surface layer]
The thickness (film thickness) of the surface layer is preferably 1 μm or more and 30 μm or less. When the thickness of the surface layer is 1 μm or more, the skeleton begins to charge up, and the effect of suppressing abnormal discharge is exhibited. Further, when the thickness of the surface layer is 30 μm or less, the discharge in the pores reaches the photosensitive drum, and an image can be formed without insufficient charging. More preferably, it is 1 μm or more and 20 μm or less. When the thickness is 20 μm or less, the polarity of the dirt adhering to the surface layer can be suitably reversed, and image defects due to the dirt adhering can be further suppressed.

Further, the ratio of the average value of the equivalent circle diameters of the particles to the film thickness is preferably 1.5 or more and 10 or less. Here, the "ratio of the average value of the equivalent circle diameters of the particles to the film thickness" means a value calculated by {(thickness) / (average value D1 of the average value of the equivalent circle diameters of the particles)}.
When the ratio of the average value of the equivalent circle diameters of the particles to the film thickness is 1.5 or more, it is considered that the effect of dividing the discharge and the effect of suppressing the adhesion of dirt are hardly reduced because there are few through holes. .. Further, if the ratio of the average value of the equivalent circle diameters of the particles to the film thickness is 10 or less, it is considered that the amount of discharge charge in the pores is rarely less than the value required for decontamination. ..

The thickness of the surface layer is confirmed as follows. A section containing the conductive support and the surface layer is cut out from the conductive member, and the thickness of the surface layer is measured by performing X-ray CT measurement. Specifically, the two-dimensional slice image obtained by the above-mentioned X-ray CT measurement was binarized by the Otsu method, and the skeleton portion and the pore portion were distinguished. In each of the binarized slice images, the ratio occupied by the skeleton part is quantified, the numerical value is confirmed from the conductive support side to the surface layer side, and the region where the ratio occupied by the skeleton part is 2% or more is defined as the surface layer. The outermost surface and the lowermost part are defined. Here, the "ratio occupied by the skeleton portion" means a value calculated by {(area of the skeleton portion) / (area of the skeleton portion + area of the pore portion)}. The longitudinal direction of the conductive member is divided into 10 equal parts, the thickness of the surface layer is measured at any one location (10 locations in total) in each of the obtained 10 regions, and the average value is the thickness of the surface layer. Satoshi.

[Porosity]
The porosity of the surface layer is preferably 20% or more and 80% or less. When the porosity is 20% or more, a sufficient amount of electric discharge in the pores can be generated for image formation. Further, when the porosity is 80% or less, the effect of reducing the diffusion of the discharge is exhibited and the abnormal discharge can be suppressed. The porosity is more preferably 50% or more and 75% or less.

The porosity of the surface layer is confirmed as follows. A section containing the conductive support and the surface layer is cut out from the conductive member, and the porosity is measured by performing X-ray CT measurement. Specifically, the two-dimensional slice image obtained by the above-mentioned measurement by X-ray CT was binarized by the Otsu method, and the skeleton portion and the pore portion were distinguished. In each binarized slice image, the area of the skeleton and the area of the pores are quantified, and the numerical values are confirmed from the conductive support side to the surface layer side, and the area occupied by the skeleton is 2% or more. Was defined as the surface layer, and the outermost surface and the lowermost part were defined.
Next, the volumes of the skeleton and the pores were calculated, and the volume of the pores was divided by the total volume of both to obtain the porosity. This is divided into 10 equal parts in the longitudinal direction of the conductive member, the porosity of the surface layer is measured at any one location (10 locations in total) in each of the obtained 10 regions, and the average value is calculated. The porosity of the surface layer.

[Material properties of resin particles]
It is important that the resin particles in the surface layer are non-conductive and are formed of resin particles containing a radiation-disintegrating type resin.

(Improvement of stain resistance over a long period of time by using resin particles containing radiation decay type resin)
In the electrophotographic image forming apparatus, a high voltage of several hundred to several thousand volts is applied to the charged member. Therefore, at the time of discharge, a large amount of energy is applied locally on the surface of the charged member even if the amount of charged charge is within the range of normal discharge. In particular, since the surface layer of the conductive member according to this embodiment has a fine porous structure having a large surface area, the energy received per unit area is large.

When the above-mentioned large discharge energy is continuously applied to the resin particles forming the surface layer, some bonds such as carbon-hydrogen in the polymer skeleton in the molecular chemical structure are broken and radicals are generated. Normally, this radical portion reacts with oxygen and water existing in the air to take in oxygen into the chemical structure, and oxidation proceeds. Alternatively, it forms new bonds with other radicals present around the molecule, producing by-products. In particular, under high temperature and high humidity conditions, this oxidation and generation of by-products become large. This is because the motility of the resin molecules increases at high temperatures and the reaction with surrounding molecules proceeds, and at high humidity, oxidation is promoted due to the increase of water molecules. As a result, the non-conductive nature of the surface layer is lowered, and the accumulated charge may leak to the conductive support, which may hinder the effect of suppressing dirt adhesion due to charge-up.

The present inventors have difficulty in improving the conductivity of the surface layer even when the surface layer is exposed to the discharge energy for a long period of time, and electrostatically stains the surface layer for a long period of time. We repeated studies to make it difficult to adhere. As a result, it was found that it is effective to use non-conductive resin particles containing a radiation-disintegrating type resin as the resin particles constituting the skeleton.
I think the reason is as follows.

Radicals generated by radiation decay type resin are unstable due to exposure to electric discharge, and cannot stay stably at the place where they are generated, move to the surroundings, and cause a chain chemical reaction in the surrounding chemical structure. The source radical itself tends to terminate the reaction immediately.
In the resin particles, radicals generated in the chemical structure move on the main chain skeleton, and molecular cleavage that cuts the main chain skeleton is likely to occur. This molecular cleavage is likely to occur near the end of the skeleton, and the cleavage terminates the radical reaction of the main skeleton (the skeleton with the longer molecular chain) after cleavage. The skeleton separated from the main skeleton after cleavage (the skeleton that has become very short) is decomposed by a further reaction and disappears by gasification, and the entire radical reaction is terminated. The main skeleton after cleavage has a slight decrease in molecular weight, but other than that, there is no significant change compared to the original polymer skeleton structure.

Since the radical generation to the end of the reaction occur immediately in this way, oxidation and generation of by-products are unlikely to proceed regardless of the conditions of use. As a result, when resin particles containing a radioactively decaying resin are used, oxidation of the material and generation of by-products are suppressed even in a high temperature and high humidity environment and even if the surface layer is exposed to electric discharge for a long period of time. .. Therefore, the reduction in resistance of the surface layer can be suppressed, the leakage of accumulated charges can be reduced, and the effect of suppressing dirt adhesion can be maintained for a long period of time.

There is a radiation-crosslinked resin in which a new bond such as molecular cross-linking is formed by irradiation with radiation to a radiation-disintegrating type resin, and the molecular structure becomes large. Since the radiation-crosslinked resin generates stable radicals, the chances of reacting with surrounding oxygen, water, etc. increase, and oxidation and formation of by-products proceed. Therefore, the surface layer becomes low in resistance during discharge, and the accumulated charge leaks. Therefore, the resin particles of the radiation-crosslinked resin are liable to leak the accumulated charge. In particular, under high temperature and high humidity, the motility of the resin molecules increases and the reaction with surrounding molecules tends to proceed.

[Determination of radiation decay type resin]
Examples of radioactively decaying resins are described in "Radiation and Polymers" by Kenichi Shinohara et al. (Maki Shoten, 1968), pp. 89-91. In the present invention, whether or not the resin is a radioactive decay type resin is determined by measuring the change in molecular weight before and after the treatment in which radiation or energy corresponding thereto is applied. Specifically, the resin is subjected to corona discharge and analyzed by gel permeation chromatography (GPC) measurement.

For GPC measurement, it is necessary to put the target resin in a solvent to make a solution. Here, the solvent is most easily dissolved by the target resin such as toluene, chlorobenzene, tetrahydrofuran (THF), trifluoroacetic acid, 1,1,1,3,3,3-hexafluoro-2-propanol (HFIP), formic acid and the like. The solvent can be selected. When the cross-linking reaction proceeds by the corona discharge and the molecular weight becomes very large, the molecular weight cannot be measured by GPC measurement because it does not dissolve in any solvent. When such an insoluble component is 10% by mass or more with respect to the total amount of the resin, there are many cross-linking components other than the insoluble component, and it is judged to be a radiation cross-linking type. On the other hand, if it is less than 10% by mass, GPC measurement of the dissolved resin component is performed using the solution side. When the molecular weight is less than or equal to the molecular weight before the corona discharge treatment, it indicates that the molecular skeleton is preferentially cleaved, and it is judged to be a radiation decay type. If the molecular weight increases, it is a radiation cross-linked type.

[Glass transition temperature Tg of resin particle material]
The radiation decay type resin preferably has a glass transition temperature Tg of −150 ° C. or higher and 100 ° C. or lower. When the glass transition temperature Tg is −150 ° C. or higher, the shape of the resin particles does not change and the porosity does not decrease even if energy due to electric discharge is applied, which does not lead to poor charging. On the other hand, when the glass transition temperature Tg is 100 ° C. or lower, the treatment temperature for forming the neck is not too high.

In the treatment at high temperature, the neck is formed sufficiently uniformly, so that black spots do not appear due to the non-uniformity of the surface layer. Furthermore, the glass transition temperature Tg should be −150 ° C. or higher and 0 ° C. or lower in order to activate the molecular motion, promote the binding reaction when the neck is formed, and improve the continuity of the surface layer. Is more preferable.
In consideration of these characteristics, it is preferable to use polyisobutylene, which has a glass transition temperature Tg capable of preferably forming a neck and is a radiation decay type resin.

[Measurement of glass transition temperature Tg]
The glass transition temperature Tg of the resin particles forming the surface layer can be measured by, for example, differential scanning calorimetry (DSC) by recovering the surface layer from the conductive member using tweezers or the like. Similarly, the DSC measurement may be performed after the surface layer is recovered from the conductive member, heated, or melted with a solvent to form a sheet.

〔Additive〕
In order to adjust the electrical resistivity of the surface layer, an additive may be added to the material of the skeleton as long as the effect of the invention is not impaired and the surface layer can be formed. Examples of additives include the following. Conductive particles obtained by coating the surface of particles with oxides such as carbon black, graphite, and tin oxide that exhibit electron conductivity, metals such as copper and silver, and oxides and metals. An ionic conductivity-imparting agent having ion exchange performance such as a quaternary ammonium salt showing ionic conductivity and a sulfonate. These may be used alone or in combination of two or more. Further, even if a filler, a softener, a processing aid, a tackifier, a tackifier, a dispersant, etc., which are generally used as a resin compounding agent, are added as long as the effect of the present invention is not impaired. good.

[Radical additive]
A radical scavenger may be added to the resin particles. Radical scavengers have the function of capturing stable radicals around themselves and terminating the reaction. As a result, even if stable radicals are generated in the structure of the radioactive decay type resin when the discharge energy is applied, the radical reaction can be terminated at an early stage. Therefore, oxidation can be suppressed due to the remaining stable radicals. As a specific radical scavenger, antioxidants such as p-hydroquinone and 3,5-dibutyl-4-hydroxytoluene, which also have an effect of suppressing the formation of peroxide by air oxidation or the like, are preferable.

[Molecular weight of radiation decay type resin]
The weight average molecular weight (Mw) of the radiation-disintegrating resin is preferably 50,000 or more and 1.5 million or less. When the weight average molecular weight is 50,000 or more and 1.5 million or less, the resin particles have hardness due to the high molecular weight, so that the shape of the surface layer does not change even when used for a long period of time, and stable discharge is performed. Can be maintained.
More preferably, it is 300,000 or more and 1.5 million or less. Further, when the weight average molecular weight is 300,000 or more, the destruction of the surface layer can be suppressed even when the surface layer is used for a long time while in contact with other members.

The weight average molecular weight of the non-conductive radiation-disintegrating resin forming the surface layer can be measured as follows. The layer of the network structure can be recovered from the conductive member using tweezers or the like, and can be measured by, for example, microsampling mass spectrometry (μ-MS) or gel permeation chromatography analysis (GPC). Similarly, the mass spectrometry may be performed after the surface layer is recovered from the conductive member, heated, or melted with a solvent to form a sheet.

[Control of surface layer formation method and neck diameter]
The method for forming the surface layer is not particularly limited as long as the surface layer can be formed, and the particles may be deposited on the conductive support and then bonded to each other via the neck in a subsequent step. Examples of the method for depositing the particles on the conductive support include the following methods. Direct coating such as roll-to-roll coating by impregnating fine particles in a brush roller or sponge roller, electrostatic powder coating method, fluidized immersion coating method, electrostatic flow immersion coating method, thermal spray powder coating method, electrospray method , Method of spraying fine particle dispersion liquid by spray painting, etc. Among them, since the peeling and coating of the fine particles occur at the same time, the film thickness control of the surface layer can be preferably realized, and further, the fine particles can be contained in a brush roller or a sponge roller and compressed at the same time as the coating. The method of coating is preferable. The coating amount can be suitably controlled by the number of rotations of the roll and the rotation time.

Examples of the method of bonding the particles via the neck include heating, heat pressure bonding, infrared radiation, and a method of bonding by a fixing resin. Among them, since the particles inside the surface layer can be suitably fused, a method of heating or heat-bonding the particle deposition film on which the particles are deposited is preferable.
Regarding the control of the neck ratio R below, it may be controlled by the conditions in the bonding step, for example, the heating temperature and the heating time.

<Second embodiment>
A second embodiment of the conductive member according to the present invention will be described.
The conductive member according to the second embodiment has the following configuration.
It has a conductive support, an intermediate layer, and a surface layer in this order, and the surface layer has a three-dimensionally continuous skeleton and has pores that communicate in the thickness direction.
A through hole is included when an arbitrary 150 μm square region on the surface of the surface layer is photographed and the region is divided into 60 equal parts vertically and 60 equal parts horizontally and equally divided into 3,600 squares. The number of squares is 100 or less,
The skeleton is non-conductive and
The skeleton is composed of a plurality of resin particles bonded to each other via a neck.
The average value D1 of the equivalent circle diameters of the resin particles is 0.1 μm or more and 20 μm or less, and
The intermediate layer contains a radioactive decay type resin and is non-conductive.

[Intermediate layer containing radiation decay type resin]
As described above, when the energy of electric discharge is applied to the surface layer, if oxidation or by-products adhere, the electric charge accumulated from the surface layer leaks, and the effect of suppressing the adhesion of dirt is reduced. ..
As a result of diligent studies, the present inventors have conducted a surface layer by providing a non-conductive intermediate layer containing a radioactively decaying resin even if the resin particles constituting the surface layer do not contain the radioactively decaying resin. It was found that the leakage of accumulated charge to the conductive support can be suppressed.
By suppressing the leakage of accumulated charges from the surface layer, the effect of suppressing the adhesion of dirt to the surface of the conductive member can be maintained for a long period of time.

The reason why the leakage of accumulated charge can be suppressed is as follows.
Since the surface layer has pores that communicate with each other, electric discharge occurs from the outermost pores of the surface layer to the lowest layer on the conductive support side. That is, the surface layer is exposed to the electric discharge over the entire area in the thickness direction. Therefore, the resistance of the surface layer is lowered due to oxidation by discharge energy and adhesion of by-products, that is, leakage of accumulated charges may occur on the entire surface layer. Since the accumulated charge leaks to the conductive support due to electrostatic attraction because the accumulated charge has the opposite polarity to the polarity of the voltage applied to the conductive support.

Therefore, by providing an intermediate layer between the surface layer and the conductive support, which has the effect of blocking the accumulated charges leaking from the surface layer, it is possible to suppress the leakage of the accumulated charges in the surface layer. can. Further, the influence of the electric discharge is considered to reach the lowermost end of the surface layer on the conductive support side, so that the surface is exposed to the electric discharge. Therefore, the intermediate layer is a radiation-disintegrating resin that does not generate oxidation or by-products due to electric discharge, and needs to be non-conductive in order to block charge leakage.
Further, as shown below, by optimizing the volume resistivity of the intermediate layer, the intermediate layer can also be charged up. As a result, it is possible to raise the amount of charge-up as a conductive member, and the effect of suppressing abnormal discharge and the effect of suppressing dirt adhesion are improved.

[Volume resistivity of the intermediate layer]
The intermediate layer needs to be non-conductive in order to prevent the accumulated charge from leaking to the conductive support. Non-conductive means that the volume resistivity is 1 × 10 ¹⁰ Ω · cm or more.
The volume resistivity of the intermediate layer is preferably 1 × 10 ¹² Ω · cm or more and 1 × 10 ¹⁷ Ω · cm or less. By setting the volume resistivity to 1 × 10 ¹² Ω · cm or more, leakage of accumulated charges in the surface layer can be suppressed. On the other hand, by setting the volume resistivity to 1 × 10 ¹⁷ Ω · cm or less, it is possible to sufficiently supply the electric charge of the discharge in the pores of the surface layer. If the volume resistivity is larger than this, the amount of discharge charge is insufficient, resulting in poor charging.

Further, when the volume resistivity is 1 × 10 ¹⁵ Ω ・ cm or more and 1 × 10 ¹⁷ Ω ・ cm or less, the intermediate layer receives a discharge and can be charged up. Since the intermediate layer is integrated, it is more preferable to charge up the intermediate layer because the variation can be reduced and the effect of suppressing dirt adhesion can be made uniform.

The method for measuring the volume resistivity of the intermediate layer is as follows. For the conductive member in which the intermediate layer after peeling is on the outermost surface, the measured value measured by the conductive mode using an atomic force microscope (AFM) can be adopted. The intermediate layer is cut into a sheet using a manipulator, and metal vapor deposition is applied to one side of the intermediate layer. A DC power supply is connected to the metal-deposited surface, a voltage is applied, the free end of the cantilever is brought into contact with the other surface of the intermediate layer, and a current image is obtained through the AFM main body. The current value on the surface of 100 randomly selected points is measured, and the volume resistivity can be calculated from the average current value of the top 10 measured low current values, the average film thickness, and the contact area of the cantilever.
The volume resistivity of the intermediate layer after the durability evaluation can be measured in the same manner as described above after the surface layer is peeled off with a mending tape, tweezers, or the like so as not to damage the intermediate layer.

[Thickness of intermediate layer]
The thickness (film thickness) of the intermediate layer is preferably 1 μm or more and 5 μm or less. When the film thickness is 1 μm or more, it is possible to prevent the accumulated charge of the surface layer from leaking to the conductive support, and the effect of suppressing dirt adhesion can be maintained. When the maximum value of the film thickness is 5 μm or less, it is possible to suppress charging defects caused by insufficient discharge charge amount.

To measure the film thickness of the intermediate layer, cut out a sheet with a sharp blade such as a razor or a manipulator so that the cross section of the intermediate layer is exposed, and measure this in the field of view of an optical microscope or an electron microscope. When the maximum value of the film thickness is A and the minimum value is B, 1 μm ≦ B and A ≦ 5 μm are preferable. The longitudinal direction of the conductive member is divided into 10 equal parts, the thickness of the intermediate layer is measured at any one location (10 locations in total) in each of the obtained 10 regions, and the average value is taken as the intermediate layer. The thickness of.

[Material of intermediate layer]
If the intermediate layer contains a radiation-disintegrating resin and is non-conductive, the resistance does not decrease even if it receives a discharge, so that the leakage of electric charge always accumulated between the surface layer and the conductive support is blocked. It becomes possible. As a result, the effect of suppressing dirt adhesion can be maintained for a long period of time. As for the radiation-disintegrating type resin, as with the surface layer resin, an example of the radiation-disintegrating type resin was introduced in "Radiation and Polymers" by Kenichi Shinohara et al. (Maki Shoten, 1968), as mentioned above. ing.
Specific examples thereof include polyacetal resin, polyalphastyrene, and cellulose resin. In particular, it is preferably formed of an acrylic resin having a structural unit represented by the formula (1).

^{In addition, R 1} in the formula (1) represents a hydrocarbon group having 1 to 6 carbon atoms. When R ¹ is a hydrocarbon group having 1 to 6 carbon atoms, there are not too many parts that can be radicalized at the time of discharge, and oxidation that reacts with surrounding oxygen and water and formation of by-products are likely to proceed. do not.
In addition, a copolymer produced from a combination of two or more kinds of monomers which are raw materials of these polymers may be used. Examples of the resin material include the following. Polymethyl methacrylate, ethyl polymethacrylate, propyl polymethacrylate, isopropyl polymethacrylate, butyl polymethacrylate, tertiary butyl polymethacrylate, isobutyl polymethacrylate, benzyl polymethacrylate and the like. The reaction mechanism that can be considered when the repeating unit is represented by the formula (1) will be described using the reaction formula (1).

In the reaction formula (1), n represents the amount of repetition and the dots represent radicals. When energy from electric discharge is applied, hydrogen on the methyl group bonded to the polymer skeleton that becomes the main chain is separated, and radicals are generated. This radical generation site is likely to occur near the end of the skeleton. The generated radicals are very unstable due to the influence of the electron-withdrawing action of the ester bond. Therefore, the next reaction, that is, the radical tries to move to another part. At that time, due to the influence of the ester bond, it moves in the direction of the main clavicle. The bond between the quaternary carbon to which the methyl group is bonded and the carbon adjacent to the main chain skeleton is broken, and the adjacent carbon is radicalized, resulting in molecular cleavage. After molecular cleavage, the main skeleton is divided into a skeleton with a very short molecular chain, the reaction is terminated on the main skeleton side, and radicals remain on the shortened skeleton side. In the skeleton on the side where radicals remain, decomposition proceeds by further reaction, radicals disappear by gasification, and the entire radical reaction ends. That is, it is considered that unstable radicals are formed and the reaction is terminated rapidly, so that there is less chance of reacting with surrounding oxygen and water, and oxidation is suppressed.

^{It is more preferable that R 1} in the formula (1) is a linear or branched alkyl group having 2 or more and 6 or less carbon atoms. Since it does not have a cyclic structure, stable radical formation due to resonance or the like is suppressed, and since there are a plurality of carbons and three-dimensional obstacles increase, the chance of reaction with the discharge product in this portion decreases, and oxidation is suppressed.
More preferably, R ¹ is a material composed of groups represented by the following formulas (2) to (5).
(2) -C (CH ₃ ) ₃ ,
(3) -CH (CH ₃ ) ₂ ,
(4) -CH (CH ₃ ) -C (CH ₃ ) ₃ ,
(5) -C (CH ₃ ) _2- CH (CH ₃ ) ₂ .

There is no secondary carbon on R ¹ that easily becomes a radical, and oxidation is suppressed by increasing steric hindrance.
Further, more preferably, it is a material composed of (2) -C (CH ₃ ) _3. This is because the tertiary carbon is eliminated and the quaternary carbon and the primary carbon are formed, so that stable radicals are less likely to be formed and discharge deterioration due to oxidation is suppressed. The "quaternary carbon" means a carbon atom having 3 adjacent carbon atoms bonded to a carbon atom and bonded to an atom other than a hydrogen atom (specifically, an oxygen atom).

[Manufacturing method of intermediate layer]
The intermediate layer may be formed by a known method as described below, as long as a uniform film can be formed on the conductive support. Coating methods such as dipping, roll coating method, spray method, electrostatic coating method, tube molding method such as extrusion and multicolor molding, inflation molding method, blow molding method, laminating, etc. It is preferable to form an intermediate layer by a dipping method in that charges can be more reliably accumulated over the entire surface with a film thickness of 1 μm or more and 5 μm or less.

[The surface layer is also a radioactive decay type resin]
In the conductive member according to the second embodiment, the resin particles constituting the skeleton of the surface layer do not need to contain a radiation decay type resin.
However, when a radiation-disintegrating type resin is contained as the resin particles, the surface layer itself can maintain the accumulated charge, and the intermediate layer can also suppress the leakage of the accumulated charge. Thereby, the effect of suppressing the adhesion of dirt can be further improved.

<Structure common to the conductive members according to the first embodiment and the second embodiment>
[Rigid structure that protects the surface layer]
Dirt that tends to adhere to the surface layer adheres physically or electrostatically. When a rigid structure that protects the surface layer is introduced, the surface layer does not come into contact with the photosensitive drum, so that the phenomenon of physical contamination can be almost avoided.
Moreover, when the structure of the surface layer changes, the discharge characteristics may also change. Therefore, especially for long-term use, by introducing a rigid structure that protects the surface layer, friction and wear between the surface of the photosensitive drum and the surface layer can be reduced, and the structure of the surface layer can be changed. It is preferable to suppress it. Here, the rigid body structure refers to a structure in which the amount of deformation of the rigid body structure caused by contact with the photosensitive drum is 1 μm or less. The method of providing the rigid body structure is not limited as long as the effect of the present invention is not impaired, and examples thereof include a method of forming a convex portion on the surface of the conductive support, a method of introducing a separating member into the conductive member, and the like. Be done.

[Convex on the surface of the conductive support]
When the conductive support has a configuration as shown in FIG. 4A, a method of processing the surface of the core metal 42 into a shape having a convex portion can be mentioned. An example is a method of forming a convex portion on the surface of the core metal 42 by sandblasting, laser processing, polishing or the like. The convex portion may be formed by a method other than this.

When the conductive support has a configuration as shown in FIG. 4B, a method of processing the surface of the conductive resin layer 44 into a shape having a convex portion can be mentioned. Examples include a method of processing the conductive resin layer 44 by sandblasting, laser processing, polishing, etc., a method of dispersing fillers such as organic particles and inorganic particles in the conductive resin layer 44, and the like.

Examples of constituent materials of organic particles include the following. Nylon resin, polyethylene resin, polypropylene resin, polyester resin, polystyrene resin, polyurethane resin, styrene-acrylic copolymer, polymethylmethacrylate resin, epoxy resin, phenol resin, melamine resin, cellulose resin, polyolefin resin, silicone resin, etc. These may be used alone or in combination of two or more.

Further, examples of the constituent materials of the inorganic particles include the following. Silicon oxide such as silica, aluminum oxide, titanium oxide, zinc oxide, calcium carbonate, magnesium carbonate, aluminum silicate, strontium silicate, barium silicate, calcium tungstate, clay minerals, mica, talc, kaolin, etc. These may be used alone or in combination of two or more. Moreover, both organic particles and inorganic particles may be used.
In addition to the method of processing the conductive support as described above, a method of introducing a convex portion independent of the conductive support can be mentioned. For example, a method of winding a thread-like member such as a wire can be mentioned.

The density of the convex portion is such that one side at an arbitrary position on the surface of the surface layer is 1.0 mm when observed from the direction facing the surface layer in order to obtain the effect of protecting the porous body. It is preferable that at least a part of the rigid structure is always observed in the square area. The size and thickness of the convex portion are not limited as long as the effect of the present invention is not impaired. Specifically, it is preferable that the range does not cause image defects due to the presence of the convex portion. The height of the convex portion is not limited as long as it is larger than the thickness of the surface layer and does not interfere with the effect of the present invention. Specifically, it is preferable that the height is at least larger than the thickness of the surface layer and that charging defects due to a large discharge gap do not occur.

[Separation member]
The separating member is not limited as long as the photosensitive drum and the surface layer can be separated and the effect of the present invention is not impaired, and examples thereof include a ring and a spacer.
The following method can be mentioned as an example of the method of introducing the separating member. When the conductive member has a roller shape, a ring having a larger outer diameter than the conductive member and having a hardness capable of holding a gap between the photosensitive drum and the conductive member is provided with a rotation center of the ring and the conductive member. How to arrange them in the same position. When the conductive member has a blade shape, a method of introducing a spacer that can separate the conductive member and the photosensitive drum so that they do not rub or wear.

The material constituting the separating member is not limited as long as the effect of the present invention is not impaired, and a known non-conductive material may be appropriately used in order to prevent energization through the separating member. Examples thereof include polymer materials having excellent slidability such as polyacetal resin, high molecular weight polyethylene resin and nylon resin, and metal oxide materials such as titanium oxide and aluminum oxide. These may be used alone or in combination of two or more.
The position where the separating member is introduced is not limited as long as the effect of the present invention is not impaired, and may be installed, for example, at the end of the conductive support in the longitudinal direction.
FIG. 6 shows an example (roller shape) of the conductive member when the separating member is introduced. In FIG. 6, 60 is a conductive member, 61 is a separating member, and 62 is a conductive shaft core.

<Process cartridge>
FIG. 7 is a schematic cross-sectional view of a process cartridge for electrophotographic which includes a conductive member as a charging roller. This process cartridge integrates a developing device and a charging device, and is configured to be removable from the main body of the electrophotographic device. The developing apparatus integrates at least the developing roller 73 and the toner container 76, and may include a toner supply roller 74, a toner 79, a developing blade 78, and a stirring blade 710, if necessary. The charging device is at least integrated with the photosensitive drum 71, the cleaning blade 75, and the charging roller 72, and may include a waste toner container 77. A voltage is applied to each of the charging roller 72, the developing roller 73, the toner supply roller 74, and the developing blade 78.

<Electrographer>
FIG. 8 is a schematic configuration diagram of an electrophotographic apparatus using a conductive member as a charging roller. This electrophotographic apparatus is a color electrophotographic apparatus in which the four process cartridges are detachably attached. Black, magenta, yellow, and cyan toners are used in each process cartridge. The photosensitive drum 81 rotates in the direction of the arrow and is uniformly charged by the charging roller 82 to which a voltage is applied from the charging bias power supply, and an electrostatic latent image is formed on the surface by the exposure light 811.
On the other hand, the toner 89 stored in the toner container 86 is supplied to the toner supply roller 84 by the stirring blade 810, and is conveyed from the toner supply roller 84 onto the developing roller 83. Then, the developing blade 88 arranged in contact with the developing roller 93 uniformly coats the toner 89 on the surface of the developing roller 83, and the toner 89 is charged by triboelectric charging.
The electrostatic latent image is developed by applying toner 89 conveyed by a developing roller 83 which is arranged in contact with the photosensitive drum 81, and is visualized as a toner image.

The visualized toner image on the photosensitive drum is transferred to the intermediate transfer belt 815 supported and driven by the tension roller 813 and the intermediate transfer belt drive roller 814 by the primary transfer roller 812 to which a voltage is applied by the primary transfer bias power supply. NS. Toner images of each color are sequentially superimposed to form a color image on the intermediate transfer belt.
The transfer material 819 is fed into the apparatus by a paper feed roller (not shown), and is conveyed between the intermediate transfer belt 815 and the secondary transfer roller 816. A voltage is applied to the secondary transfer roller 816 from the secondary transfer bias power supply (not shown) to transfer the color image on the intermediate transfer belt 815 to the transfer material 819. The transfer material 819 on which the color image is transferred is fixed by the fixing device 818, and is discharged to the outside of the apparatus to complete the printing operation.

On the other hand, the toner remaining on the photosensitive drum without being transferred is scraped off by the cleaning blade 85 and stored in the waste toner storage container 87, and the cleaned photosensitive drum 81 is repeatedly used in the above-mentioned steps. Further, the toner remaining on the intermediate transfer belt 815 without being transferred is also scraped off by the cleaning device 817.
According to one aspect of the present invention, it is possible to provide a conductive member which can suppress abnormal discharge and stain adhesion even when the electrophotographic apparatus is used for a long period of time and can form a good image. Further, according to another aspect of the present invention, a process capable of suppressing the generation of a white-out image for a long period of time, further suppressing a decrease in the charging potential caused by adhesion of stains to a charging member, and suppressing image defects. Cartridges and electrophotographic devices can be provided.

<Example 1>
[1. Fabrication of conductive support]
A round bar-shaped free-cutting steel having a total length of 252 mm having different outer diameters was prepared. The range of the center 230 mm excluding the both ends 11 mm of the round bar has an outer diameter of 8.5 mm, and the portion of the both ends 11 mm has an outer diameter of 6 mm. In Example 1, the round bar-shaped free-cutting steel was used as the conductive support A1.

[2. Preparation of resin particles]
Polyisobutylene (weight average molecular weight 1 million, manufactured by Sigma-Aldrich) was freeze-ground using a freezing crusher (JFC-2000 (manufactured by Nippon Analytical Industry Co., Ltd.)). Next, crushing and classification was performed using a media stirring type dry continuous ultrafine crusher (trade name: Fine Mill (SF type); manufactured by Nippon Coke Industries, Ltd.) with a built-in classifier to remove coarse powder of 50 μm or more. Next, polyisobutylene obtained by classifying and removing fine powder having a particle size of 2 μm or less and coarse powder having a particle size of 8 μm or more using a wind power classifier (trade name: Elvo Jet Lab EJ-L3; manufactured by Nittetsu Mining Co., Ltd.). Obtained particles.

[3. Surface layer formation]
FIG. 9 shows a schematic view of a coating device for coating particles to form a surface layer. The powder coating device includes particles 90, a particle storage unit 91, a particle coating roller 92, and a particle coating member 93, and a surface layer can be formed by installing the conductive support A1 as the particle coating member 93.

The particle coating roller 92 is an elastic sponge roller in which a foam layer is formed on the outer periphery of the conductive core metal, and is arranged so as to form a predetermined contact region (nip portion) at a portion facing the particle coated member 93. , Rotate in the direction of the arrow (clockwise) shown. At this time, the particle coating roller 92 is in contact with the particle coating member with a predetermined amount of penetration, that is, the particle coating roller 92 has a recess formed by the particle coating member 93. When the particles are applied, they rotate so as to move in opposite directions in the contact region, and by this operation, the particles are applied to the particle-applied member 93 by the particle-applying roller 92, and the particles are applied on the particle-applied member 93. The particles are being stripped.

The polyisobutylene particles produced by freeze pulverization as the particles 90 forming the surface layer are driven and rotated at 90 rpm for the particle coating roller 92 and 100 rpm for the conductive support A1 for 10 seconds to be applied to the conductive support A1 and not heated. A conductive member a1 was obtained.
Next, the unheated conductive member a1 was carried into an oven and heated at a temperature of 80 ° C. for 2 hours to obtain a conductive member (charged roller) A1 for electrophotographic.

(4. Characteristic evaluation)
The conductive member A1 of this example was subjected to the following evaluation test. The evaluation results are shown in Table 6. When the conductive member is a roller-shaped conductive member, the x-axis direction, the y-axis direction, and the z-axis direction mean the following directions, respectively.
The x-axis direction is the longitudinal direction of the roller (conductive member).
The y-axis direction is the tangential direction in the cross section (that is, the circular cross section) of the roller (conductive member) orthogonal to the x-axis.
The z-axis direction is the radial direction in the cross section of the roller (conductive member) orthogonal to the x-axis. Further, the "xy plane" means a plane orthogonal to the z-axis, and the "yz cross section" means a cross section orthogonal to the x-axis.

[Evaluation 4-1.3 Confirmation of dimensionally continuous skeleton and pores communicating in the thickness direction, and confirmation of the presence or absence of a neck between a plurality of resin particles constituting the skeleton]
Whether or not the surface layer had a co-continuous structure was confirmed by the following method. Using the focused ion beam method, the surface layer of the conductive member A1 has a length of 250 μm in each of the x-axis direction and the y-axis direction, and a depth of 700 μm including the conductive support A1 in the z-axis direction. The section was cut out with. Next, a three-dimensional reconstruction was performed on this section using an X-ray CT inspection device (trade name: TOHKEN-SkyScan2011 (radioactive source: TX-300), manufactured by Mars Tohken X-ray Inspection Co., Ltd.). .. From the obtained three-dimensional image, a two-dimensional slice image (parallel to the xy plane) was cut out at an interval of 1 μm with respect to the z-axis. Next, these slice images were binarized to distinguish between the skeleton and the pores. The slice images were checked in order with respect to the z-axis, and it was confirmed whether or not the skeleton portion was three-dimensionally continuous and the pore portion communicated in the thickness direction. In the table showing the results of this evaluation, "Y" is given when the skeleton is three-dimensionally continuous and the pores are communicated in the thickness direction, and the skeleton is three-dimensionally continuous and the pores are connected. Is not communicated in the thickness direction, and is indicated as "N".
In addition, it was confirmed whether or not the skeleton portion was composed of a plurality of resin particles bonded to each other via the neck. In the table showing the results of this evaluation, "Y" when the skeleton part is composed of a plurality of resin particles bonded to each other via the neck, and a plurality of resins in which the skeleton part is bonded to each other via the neck. When it is not composed of particles, it is indicated as "N".

[Evaluation 4-2. Evaluation of through holes]
Platinum was vapor-deposited on the surface of the section to obtain a vapor-deposited section. Next, the surface of the vapor-deposited section was photographed from the z-axis direction using a scanning electron microscope (SEM) (trade name: S-4800, manufactured by Hitachi High-Technologies Corporation) at a magnification of 1000 to obtain a surface image.
Next, the surface image was created by image processing software Image-pro plus (product name, manufactured by Media Cybernetics) in a 150 μm square area with 59 dividing lines vertically and 59 horizontally at 2.5 μm intervals, for a total of 59 division lines. A group of 3,600 squares was formed and an evaluation image was obtained.

Next, in the evaluation image, the number of squares including the surface of the conductive support was visually counted out of the 3,600 grids (squares). The evaluation was performed according to the following criteria. The evaluation results are shown in Table 6. The "square including the surface of the conductive support" means "a square in which the surface of the conductive support can be visually confirmed from the surface of the surface layer".
<Evaluation criteria>
Rank A: The total number of squares including the surface of the conductive support is 5 or less.
Rank B: The total number of squares including the surface of the conductive support is 6 or more and 25 or less.
Rank C: The total number of squares including the surface of the conductive support is 26 or more and 100 or less.
Rank D: The total number of squares including the surface of the conductive support is 101 or more.

[Evaluation 4-3. Evaluation of non-conductiveness of surface layer]
The volume resistivity of the surface layer was measured in a contact mode using a scanning probe microscope (SPM) (trade name: Q-Scope250, manufactured by Questant Instrument Corporation).

First, the conductive member A1 (length in the longitudinal direction: 230 mm) was equally divided into 10 regions in the longitudinal direction. From the surface layer in each region, the skeleton forming the surface layer was recovered with tweezers, and 10 test pieces were prepared. Each of the test pieces was placed on a metal plate made of stainless steel to prepare 10 measurement sections. Next, for each measurement section, the cantilever of SPM was brought into contact with the sample on the metal plate, a voltage of 50 V was applied to the cantilever, and the current value was measured.
Further, in the SPM, the thickness of the portion where the current value was measured of the sample in each measurement section was calculated, and the contact area between the test piece and the cantilever was calculated. The volume resistivity was calculated from the thickness and the contact area. The average value of the volume resistivity obtained from each measurement section was taken as the volume resistivity of the surface layer in this evaluation.

The above measurement was performed before the durability evaluation and after the durability evaluation, and the reduction rate of the volume resistivity was calculated from the quotient of these two values.

[Evaluation 4-4. Evaluation of surface layer charge-up amount]
The surface potential of the conductive member (charged member) due to the corona discharge was measured using a charge amount measuring device (trade name: DRA-2000L, manufactured by QEA Co., Ltd.). Specifically, the corona discharger of the charge amount measuring device is arranged so that the gap between the grid portion and the surface of the conductive member A1 is 1 mm. Next, a voltage of 8 kV is applied to the corona discharger to generate a discharge to charge the surface of the conductive member, and the surface potential of the conductive member is measured 10 seconds after the end of the discharge. Measurements were performed before and after the durability evaluation in order to confirm the effect of suppressing dirt adhesion due to long-term use.

[Evaluation 4-5. Evaluation of the average value D1 of the equivalent circle diameter of the particles]
While observing with a 1,000x stereomicroscope, the surface layer on the surface of the section is broken down with tweezers, and care is taken not to deform the particles on the surface of the conductive support, and the particles are decomposed into individual pieces. did. Next, platinum was vapor-deposited to obtain a thin-film deposition section. Next, the surface of the vapor-deposited section was photographed from the z-axis direction using a scanning electron microscope (SEM) (trade name: S-4800, manufactured by Hitachi High-Technologies Corporation) at a magnification of 1,000 to obtain a surface image. rice field.

Next, the surface image is processed using the image processing software Image-pro plus (product name, manufactured by Media Cybernetics) so that the particles are white and the surface of the conductive support is black, and the counting function is optional. The equivalent circle diameter of the 50 particles was measured. This is divided into 10 equal parts in the longitudinal direction of the conductive member A1, the above measurement is performed on the obtained 10 regions, and the circle-equivalent diameter of an arbitrary total of 500 particles is measured, and the 500 particles are measured. The arithmetic mean of the equivalent circle diameter was defined as the average value D1 of the equivalent circle diameter of the particles.

[Evaluation 4-6. Evaluation of the average value D2 of the equivalent circle diameter of the neck cross section]
Of the 50 particles whose average value D1 of the equivalent circle diameter of the particles was measured, the equivalent circle diameter of 20 necks was measured by the distance measurement function of the image processing software Image-pro plus (product name, manufactured by Media Cybernetics). Used and measured. Next, the ratio of the equivalent circle diameter D1 of the particles to the equivalent circle diameter D2 of the neck was calculated for 20 particles.
The above operation is performed at any one point (200 points in total) in each of the 10 regions obtained by dividing the conductive member A1 into 10 equal parts in the longitudinal direction, and the circle-equivalent diameter D1 of the 200 particles. The arithmetic mean of the ratio between the neck and the equivalent circle diameter D2 of the neck was defined as the neck ratio R.

[Evaluation 4-7. Evaluation of surface layer thickness]
The two-dimensional slice image obtained by the above-mentioned X-ray CT measurement was binarized, and the skeleton portion and the pore portion were distinguished. In each binarized slice image, the ratio occupied by the skeleton part was quantified, the numerical value of each region from the conductive support side to the surface layer side was confirmed, and the region occupied by the skeleton part was 2% or more. Was used as the outermost surface portion of the surface layer. By the above method, the thickness of the surface layer (thickness from the surface of the conductive support to the outermost surface portion of the surface layer) was measured.
The above work is performed at any one point (10 points in total) in each of the 10 regions obtained by dividing the conductive member A1 into 10 equal parts in the longitudinal direction, and the average thickness thereof is defined as the thickness of the surface layer. did.

[Evaluation 4-8. Evaluation of surface layer porosity]
In the three-dimensional image obtained by the evaluation of the X-ray CT, the proportion occupied by the pores was quantified, and the porosity of the surface layer was determined. The above work is performed at any one point (10 points in total) in each of the 10 regions obtained by dividing the conductive member A1 into 10 equal parts in the longitudinal direction, and the average value is the porosity of the surface layer. And said.

[Evaluation 4-9. Measurement of glass transition temperature Tg]
First, the surface layer of the conductive member A1 was peeled off with tweezers to obtain a sample amount of 3 mg. The differential scanning calorimetry was performed on the sample using a differential scanning calorimetry device (DSC7020AS, manufactured by Yamato Scientific Co., Ltd.). After allowing to stand at a temperature of −150 ° C. for 30 minutes, the inflow and outflow of heat energy was measured while changing the temperature to 250 ° C. at a heating rate of 10 ° C./min. The glass transition temperature Tg was obtained from the measurement data using the analysis software attached to the device.

[Evaluation 4-10. Confirmation of radiation decay of non-conductive resin particles]
This evaluation is to determine whether or not the resin particles constituting the surface layer according to the present invention are formed of a radiation-disintegrating type resin. To confirm that the resin is a radiation-disintegrating type resin, first, the resin particles constituting the surface layer are sampled from the electrophotographic conductive member immediately after production, which has not been exposed to the corona discharge, and the resin particles are selected. The molecular weight of the constituent resin is measured by gel permeation chromatography (GPC). Next, the electrophotographic conductive member is subjected to a corona discharge treatment by a predetermined method, and then the resin particles constituting the surface layer of the electrophotographic conductive member are sampled and the molecular weight is measured by GPC. .. Then, from the difference in molecular weight before and after Corona Oden, it is determined whether or not the resin in the resin particles is of the radiation decay type. The details will be described below.

First, immediately after production, a 5 mg sample is collected from the surface layer from the conductive member A1 that has never been exposed to the corona discharge. For the sample, a solvent that is easily dissolved from toluene, chlorobenzene, tetrahydrofuran (THF), trifluoroacetic acid, and 1,1,1,3,3,3-hexafluoro-2-propanol (HFIP) was selected. Prepare a sample solution having a concentration of 1% by mass. For the sample collected from the surface layer of the conductive member A1, chlorobenzene was used as the solvent.

Using the prepared sample solution, the molecular weight was measured under the following conditions. The column is stabilized in a heat chamber at a temperature of 40 ° C., and the solvent used for dissolving the sample is flowed through the column at this temperature as an eluent at a flow rate of 1 mL per minute. Inject 100 μL of the sample solution into the column. In measuring the molecular weight of a sample, the molecular weight distribution of the sample is measured by using the logarithmic value of a calibration curve prepared from several types of monodisperse polystyrene standard samples (trade names: TSKgel standard polystyrenes "0005202" to "0005211", manufactured by Tosoh Corporation). Calculated from the relationship with retention time.
A GPC gel permeation chromatograph device (trade name: HLC-8120, manufactured by Tosoh Corporation) is used as the GPC device, and a differential refractive index detector (trade name: RI-8020, manufactured by Tosoh Corporation) is used as the detector. .. Three commercially available polystyrene gel columns (trade name: TSK-GELSUPER HM-M, manufactured by Tosoh Corporation) are combined with the column.
The Mw of the sample sampled from the surface layer of the conductive member A1 before the corona discharge treatment was 1 million.

Subsequently, the corona discharge treatment of the conductive member A1 was performed using a corona discharge surface treatment device manufactured by Kasuga Electric Co., Ltd. The implementation environment was an H / H environment (environment with a temperature of 30 ° C. and a relative humidity of 80%).
A detailed method of corona discharge will be described with reference to FIG.
Both ends 102 of the conductive member 101 are fixed by the support portions 103 so that the longitudinal direction of the aluminum corona electrode 104 is parallel to the longitudinal direction of the conductive member 101, and the surface of the corona electrode 104 is the conductive member. The position was adjusted so as to face the surface of 101. The distance between the surface of the corona electrode 104 and the surface of the conductive member 101 in close contact with each other was set to 1 mm. The conductive member 101 was rotated by rotating the support portion 103 at a speed of 30 rotations per minute, and the state in which 8 KV was applied from the power supply 105 to the electrode side was continued for 2 hours.

Then, a sample of 5 mg is sampled from the surface layer of the conductive member 101, and the weight average molecular weight (Mw) is measured by GPC by the same method as described above. Then, when the Mw of the sample sampled from the conductive member after the corona discharge is smaller than the Mw of the sample sampled from the conductive member before the corona discharge, it is determined that the resin is a radiation decay type resin.
Further, when Mw increased after the corona discharge, it was determined that the resin was a radiation crosslinked type. When the resin particles constituting the surface layer and / or the intermediate layer according to each Example and Comparative Example are "radiation decay type resin", they are indicated as "Y", and when they are "radiation crosslink type resin", they are indicated as "radiation crosslink type resin". Notated as "N".

(5. Image evaluation)
The conductive member A1 was subjected to the following evaluation test.
[Evaluation 5-1. Image quality evaluation Black spot]
The effect of suppressing image defects (black spots) caused by the non-conductive skeleton in the initial stage (before the durability test (repeated use test)) of the conductive member A1 was confirmed by the following method. As an electrophotographic apparatus, an electrophotographic laser printer (trade name: Laserjet CP4525dn, manufactured by HP) was prepared. However, in order to place the conductive member in a harsher evaluation environment, the number of output sheets per unit time of the laser printer is 50 sheets / minute on A4 size paper, which is larger than the original output number. I remodeled it like this. At that time, the output speed of the recording medium was set to 300 mm / sec, and the image resolution was set to 1,200 dpi.

Next, the conductive member A1 was mounted as a charging roller on the toner cartridge dedicated to the laser printer. This toner cartridge is loaded into the above laser printer, and under an H / H environment (temperature 30 ° C., relative humidity 80% environment), a halftone image (width 1 dot, interval 2 in the direction perpendicular to the rotation direction of the photosensitive drum). An image that draws horizontal lines of dots) was output. The voltage applied between the charging roller and the electrophotographic photosensitive member at this time was set to -1,200 V. The obtained image was visually observed, and the presence or absence of image defects caused by the charging member and the degree of image defects, if any, were evaluated based on the following criteria.

<< Evaluation Criteria >>
Rank A: There is no sunspot image.
Rank B: There are some slight black spots.
Rank C: Minor black spots can be seen on the entire surface.
Rank D: Black streaks are visible and stand out.

[Evaluation 5-2. Evaluation of white spot image White spot image generation voltage]
[Evaluation 5-1. Evaluation of image quality The image obtained in [Black Pochi] was visually observed, and the presence or absence of image unevenness (white spot image) due to local strong discharge from the charged member was observed.
Then, the output of the electrophotographic image and the visual evaluation were repeated in the same manner as described above, except that the applied voltage was changed every 10V to -1,010V, -1,020V, -1,030V .... Then, the applied voltage when an electrophotographic image in which image unevenness (whiteout image) due to local strong discharge from the charging member can be visually confirmed is formed is defined as the whiteout image generation voltage before the durability test. ..

[Evaluation 5-3. Evaluation of image defects due to dirt adhesion after durability test White spot]
Next, a durability test was conducted to evaluate image defects caused by dirt adhesion.
The durability test is [Evaluation 5-1. Evaluation of image quality The process was carried out in an H / H environment using the process cartridge and the electrophotographic apparatus described in [Black Pot].
In the durability test, after outputting two images, the rotation of the photosensitive drum is completely stopped for about 3 seconds, and the intermittent image forming operation of restarting the image output is repeated to output 80,000 electrophotographic images. It is a thing. The output image at this time was an image in which the letter "E" of the alphabet having a size of 4 points was printed so that the coverage was 4% with respect to the area of A4 size paper.
After the endurance, a halftone image (an image in which a horizontal line with a width of 1 dot and an interval of 2 dots is drawn in the direction perpendicular to the rotation direction of the photosensitive drum) was output. For this halftone image, image defects due to dirt adhesion were evaluated according to the following criteria.

<< Evaluation Criteria >>
Rank A: There are no image defects due to dirt adhesion.
Rank B: Image defects (white spots) due to slight stains are observed in some parts.
Rank C: Image defects (white spots) due to slight stain adhesion are observed on the entire surface.
Rank D: Image defects (white spots) due to dirt adhesion are observed on the entire surface, and are observed as vertical streaks.

<Examples 2 to 11>
[1. Preparation of conductive support]
A conductive support was produced in the same manner as the conductive support A1 according to Example 1.

[2. Preparation of resin particles]
The resin particles used for forming the conductive member according to Examples 2 to 3 are the poly according to Example 1, except that after removing 50 μm of coarse powder, particles of 3 μm or more are classified and removed using a wind power classifier. It was prepared in the same manner as the isobutylene particles.
Further, the resin particles used for forming the conductive member according to Examples 7 to 8 are in Example 1 except that after removing 50 μm of coarse powder, particles of 15 μm or less were classified and removed using a wind power classifier. It was produced in the same manner as the polyisobutylene particles.
The resin particles used for forming the conductive member according to Examples 4 to 6 and 9 to 11 were produced in the same manner as the polyisobutylene particles according to Example 1.

[3. Surface layer formation]
Above 2. Using the resin particles prepared in 1 above, conductive members A2 to A12 were produced in the same manner as in Example 1 except that the rotation time (coating time) of the conductive support was changed as shown in Table 1.

<Examples 12 to 19>
[1. Preparation of conductive support]
A conductive support was produced in the same manner as the conductive support A1 according to Example 1.

[2. Preparation of resin particles]
The material of the resin particles was changed to the material shown in Table 2-1. Further, for the resin particles used for producing the conductive member according to Example 15, after removing 50 μm of coarse powder, particles having a size of 3 μm or more were classified and removed using a wind power classifier.
Further, as for the resin particles used for forming the conductive member according to Example 17, after removing 50 μm of coarse powder, particles of 15 μm or less were classified and removed using a wind power classifier.
Other than these, resin particles used for forming the conductive member according to Examples 12 to 19 were produced in the same manner as the polyisobutylene particles according to Example 1.

[3. Surface layer formation]
Above 2. Using the resin particles prepared in 1 above, conductive members A12 to A19 were produced in the same manner as in Example 1 except that the heating temperature and the heating time were changed as shown in Table 2-1. The molecular weight in Table 2-1 is the weight average molecular weight.

PIB: polyisobutylene; PαMS: polyα-methylstyrene; PBMA: polybutylmethacrylate; PIBMA: polyisobutylmethacrylate; POM: polyacetal

<Example 20>
When crushing and classifying, the particles were classified while heating at 50 ° C., and at this time, since the outermost surface of the particles rolls while being slightly melted, spherical particles can be obtained. The conductive member A20 was manufactured in the same manner as in Example 1 except that the spherical particles were used.

<Example 21>
First, a polyisobutylene resin was dissolved in chlorobenzene to obtain a polyisobutylene solution, and then p-hydroquinone (manufactured by Sigma Aldrich), which is a radical scavenger, was added to the polyisobutylene solution in an amount of 5% by mass. After sufficiently stirring, chlorobenzene was evaporated by heating to obtain a polyisobutylene resin to which a radical scavenger had been added.
Next, the conductive member A21 was manufactured in the same manner as in Example 1 except that the polyisobutylene resin to which the radical scavenger was added was used.

<Example 22>
Po Riisobuchiren (weight average molecular weight 400,000, Sigma Aldrich) to prepare a conductive member A22 in the same manner as in Example 20 except for using the.

<Example 23>
Each material of the type and amount shown in Table 3 was mixed with a pressure kneader to obtain an A kneaded rubber composition. Further, 166 parts by mass of the A kneaded rubber composition and each material of the type and amount shown in Table 2-2 were mixed with an open roll to prepare an unvulcanized rubber composition.

A round bar having a total length of 252 mm and an outer diameter of 6 mm was prepared by subjecting the surface of the free-cutting steel to electroless nickel plating. Next, the adhesive was applied over the entire circumference in a range of 230 mm excluding 11 mm at both ends of the round bar. As the adhesive, a conductive hot melt type adhesive was used. A roll coater was used for coating. The round bar coated with the adhesive was used as a conductive shaft core body (core metal). A conductive resin layer was provided on the surface of the core metal. Prepare a crosshead extruder with a conductive shaft core supply mechanism and an unvulcanized rubber roller discharge mechanism, attach a die with an inner diameter of 12.5 mm to the crosshead, and set the extruder and crosshead to 80 ° C. The transport speed of the conductive shaft core was adjusted to 60 mm / sec.

Under these conditions, the unvulcanized rubber composition is supplied from the extruder, the unvulcanized rubber composition is formed as an elastic layer on the outer peripheral surface of the conductive shaft core in the cross head, and the unvulcanized rubber roller is formed. Got Next, the unvulcanized rubber roller was put into a hot air vulcanization furnace at 170 ° C. and heated for 60 minutes to obtain an unpolished conductive roller. Then, the end of the elastic layer was excised and removed. Finally, the surface of the elastic layer was polished with a rotary grindstone. As a result, a conductive roller having a diameter of 8.4 mm and a diameter of 8.5 mm at the center was obtained at a position of 90 mm from the center to both ends.
The conductive member A23 was manufactured in the same manner as in Example 1 except that a conductive roller with NBR rubber was used as the conductive support.

<Example 24>
The materials shown in Table 4 were mixed by an open roll to prepare a conductive substrate produced from an unvulcanized rubber composition by the same operation as in Example 23, and a conductive roller was obtained.
The conductive member A24 was manufactured in the same manner as in Example 1 except that a conductive roller having a hydrin rubber was used as the conductive support.

<Example 25>
First, methyl isobutyl ketone was added to a caprolactone-modified acrylic polyol solution to adjust the solid content to 10% by mass. A mixed solution was prepared using the materials shown in Table 5 with respect to 1000 parts by mass of this acrylic polyol solution (100 parts by mass of solid content). At this time, the mixture of block HDI (hexamethylene diisocyanate) and block IPDI (isophorone diisocyanate) had a molar ratio (NCO / OH) of isocyanate groups to hydroxyl groups of 1.0.

Next, 210 g of the mixed solution and 200 g of glass beads having an average particle size of 0.8 mm were mixed in a 450 mL glass bottle and pre-dispersed 24 hours using a paint shaker disperser. Then, 10 phr of non-crosslinked acrylic particles (model: MX-500 manufactured by Soken Kagaku Co., Ltd.) and 200 g of glass beads having an average particle size of 0.8 mm are mixed as a medium and dispersed for 10 minutes using a paint shaker disperser. A coating material for forming a conductive resin layer was obtained. In addition, "phr" means the addition amount (part by mass) with respect to 100 parts by mass of the unvulcanized rubber composition.

The conductive support A1 was dipped in the coating material for forming the conductive resin layer with its longitudinal direction in the vertical direction, and coated by a dipping method. The immersion time of the dipping coating was 9 seconds, and the pulling speed was 20 mm / sec at the initial speed and 2 mm / sec at the final speed, during which the speed was changed linearly with time. The obtained coated product was air-dried at room temperature for 30 minutes, then dried in a hot air circulation dryer set at a temperature of 90 ° C. for 1 hour, and further dried in a hot air circulation dryer set at a temperature of 160 ° C. for 1 hour.
Then, the surface layer was formed in the same manner as in Example 1, and the conductive member A25 was manufactured.

<Example 26>
A separating member (a ring having an outer diameter of 8.6 mm, an inner diameter of 6 mm, and a width of 2 mm) was attached to the conductive member A1 to manufacture the conductive member A26.

<Comparative example 1>
The conductive member C1 was manufactured in the same manner as in Example 25 except that the surface layer was not formed.

<Comparative example 2>
The conductive member C2 was manufactured in the same manner as in Example 1 except that the surface layer was not heated.

<Comparative example 3>
The conductive member C3 was produced in the same manner as in Example 1 except that carbon particles (PC1020 manufactured by Nippon Carbon Co., Ltd.) were used as the particles.

<Comparative example 4>
The conductive member C4 was manufactured in the same manner as in Example 1 except that the average value of the equivalent circle diameters of the particles in the surface layer was 35 μm when the particles were classified by the fine mill.

<Comparative example 5>
The conductive member C5 was manufactured in the same manner as in Example 1 except that the heating temperature of the surface layer was set to 150 ° C.

<Comparative Example 6>
The conductive member C6 was produced in the same manner as in Example 1 except that the material of the particles in the surface layer was polystyrene (sigma-aldrich, weight average molecular weight: 260,000 items).

The conductive members A1 to A26 according to Examples 1 to 26 and the conductive members C1 to C6 according to Comparative Examples 1 to 6 are evaluated in Evaluations 4-1 to 4-10 and Evaluations 5-1 to 5 described in Example 1. Dedicated to -3. The results are shown in Tables 6-1 to 6-6 and Table 7. The contents of each table are as follows.
Table 6-1: The results of evaluations 4-1 to 4-4 of Examples 1 to 18 are shown.
Table 6-2: The results of evaluations 4-5-4-10 of Examples 1-18 are shown.
Table 6-3: The results of evaluations 4-1 to 4-4 of Examples 19 to 26 are shown.
Table 6-4: The results of evaluations 4-5 to 4-10 of Examples 19 to 26 are shown.
Table 6-5: The results of evaluations 4-1 to 4-4 of Comparative Examples 1 to 6 are shown.
Table 6-6: The results of evaluations 4-5 to 4-10 of Comparative Examples 1 to 6 are shown.
Table 7: The results of evaluations 5-1 to 5-3 of Examples 1 to 26 and Comparative Examples 1 to 6 are shown.

Since it does not have the conductive member C1 surface layer according to Comparative Example 1, it was not subjected to evaluations 4-1 to 4-10. In Tables 6-5 and 6-6, which will be described later, it is indicated as "-".
Further, regarding the conductive member C5 according to Comparative Example 5, since the surface layer is a film having no neck, the “average value D2 of the equivalent circle diameter of the neck cross section” according to the evaluation 4-6 in Table 6-6. The column of "" is written as "-".

<Example 27>
Examples 27 to 40 are examples of a configuration having an intermediate layer containing a radiation decay type resin.

[Formation of intermediate layer]
The intermediate layer was formed as follows.
First, 1% by mass of tertiary butyl polymethacrylate (manufactured by Sigma-Aldrich, weight average molecular weight 170,000 products) was dissolved in dimethylacetylamide to obtain a coating liquid 1.
The conductive support A1 was immersed in the coating liquid 1 with its longitudinal direction in the vertical direction and coated by the dipping method. The immersion time of the dipping coating was 9 seconds, and the pulling speed was 20 mm / sec at the initial speed and 2 mm / sec at the final speed, during which the speed was changed linearly with time. The obtained coated product was air-dried at room temperature for 30 minutes and dried in a hot air circulation dryer set at a temperature of 160 ° C. for 1 hour to obtain a conductive support B1.

[Evaluation 6-1; Evaluation of non-conductive nature of the intermediate layer]
The non-conductive property of the intermediate layer was evaluated by the following method. The volume resistivity of the intermediate layer was measured in a contact mode using a scanning probe microscope (SPM) (trade name: Q-Scope250, manufactured by Quant Instrument Corporation).
First, the conductive support B1 was equally divided into 10 regions in the longitudinal direction. Then, from each region, the intermediate layer is subjected to a focused ion beam method at a length of 1 mm in the x-axis direction and 500 μm in the y-axis direction, and at a depth of 700 μm including the conductive support A1 in the z-axis direction. Sections were cut out to prepare 10 test pieces. Next, each of the test pieces was placed on a metal plate made of stainless steel so that the portion of the conductive support A1 was in contact with the metal plate, and 10 measurement sections were obtained.
Next, the cantilever of the SPM was brought into contact with the intermediate layer portion of each measurement section, a voltage of 50 V was applied to the cantilever, and the current value was measured.

Next, the yz cross section of each test piece was observed, and the thickness of the intermediate layer was measured. Further, the volume resistivity was calculated from the thickness and the current value. The average value of the volume resistivity obtained from each test piece was taken as the volume resistivity of the intermediate layer in this evaluation.

[Evaluation 6-2; Measurement of intermediate layer thickness]
In the evaluation 6-1 above, the average value of the thickness of the intermediate layer measured from each test piece was taken as the thickness of the intermediate layer in this evaluation.

[Evaluation 6-3; Evaluation that the intermediate layer is a radiation decay type resin / Evaluation of glass transition temperature Tg]
The radiation decay type resin was determined and the glass transition temperature Tg was evaluated in the same manner as the evaluation method for the surface layer, except that the intermediate layer was peeled from the conductive support B1 to form a test piece.

[Formation of surface layer on the outer circumference of the intermediate layer]
A conductive support B1 is used instead of the conductive support A1, and polystyrene (manufactured by Sigma-Aldrich, weight average molecular weight 260,000) is used as the particles of the surface layer, and the heating temperature after particle deposition is 140 ° C. The heating time was set to 3 hours. Except for these points, the conductive member B1 was manufactured in the same manner as in Example 1.

The conductive member B1 obtained in this example was subjected to evaluations 4-1 to 4-10 and evaluations 5-1 to 5-3 described in Example 1.

<Examples 28-40>
Conductive members B2 to B14 were produced in the same manner as in Example 27, except that the coating liquid 1 was changed to the coating liquids 2 to 14 shown in Table 8 below. The intermediate layers according to the conductive members B2 to B14 were subjected to the evaluations 6-1 to 6-3 described in Example 27.
Further, the conductive members B2 to B14 were subjected to the evaluations 4-1 to 4-10 and evaluations 5-1 to 5-3 described in Example 1.

In Table 8, the molecular weight described in the “Material” column is the weight average molecular weight. The details of the abbreviations of the materials described in the same column are as follows.
PtBMA: tertiary butyl polymethacrylate (R ¹ : -C (CH ₃ ) ₃ ), PMMA: methyl polymethacrylate (R ¹ : -CH ₃ ),
PEMA: Polyethyl methacrylate (R ¹ : -CH ₂ CH ₃ ),
PBMA: Polybutyl methacrylate (R ¹ : -CH ₂ CH ₂ CH ₂ CH ₃ ),
PiBMA: Isobutyl polymethacrylate (R ¹ : -CH ₂ CH (CH ₃ ) ₂ ),
PiPMA: Polyisopropyl methacrylate (R ¹ : -CH (CH ₃ ) ₂ ),
P (B-iB) MA: Butyl methacrylate-isobutyl methacrylate copolymer,
P (BE) MA: Butyl methacrylate-ethyl methacrylate copolymer,
ParufaMS: poly-alpha-methyl acid styrene PCMA: poly cyclohexyl methacrylate ^(R 1: -Cy),
POM: Polyacetal HFIP: 1,1,1,3,3,3-hexafluoro-2-propanol.

<Example 41>
An intermediate layer was produced in the same manner as in Example 27, and then a surface layer was formed in the same manner as in Example 1 to produce a conductive member B15. The intermediate layer related to the conductive member B15 was subjected to the evaluations 6-1 to 6-3 described in Example 27.
Further, the conductive member B15 was subjected to evaluations 4-1 to 4-10 and evaluations 5-1 to 5-3 described in Example 1.

<Comparative Example 7>
The conductive member C7 was produced in the same manner as in Example 27, except that polystyrene (sigma-aldrich, weight average molecular weight 260,000 products) was used for both the material of the particles in the surface layer and the material of the intermediate layer. The intermediate layer related to the conductive member C7 was subjected to the evaluations 6-1 to 6-3 described in Example 27.
Further, the conductive member C7 was subjected to evaluations 4-1 to 4-10 and evaluations 5-1 to 5-3 described in Example 1.

<Comparative Example 8>
Conductivity in the same manner as in Example 27, except that a quaternary ammonium salt (trade name: ADEKA Sizer LV70, manufactured by Asahi Denka Kogyo Co., Ltd.) was added to the coating liquid 1 as an ionic conductivity imparting agent in an amount of 5% by mass. The sex member C8 was manufactured. The intermediate layer related to the conductive member C8 was subjected to the evaluations 6-1 to 6-3 described in Example 27.
Further, the conductive member C8 was subjected to evaluations 4-1 to 4-10 and evaluations 5-1 to 5-3 described in Example 1.
Table 9 shows the evaluation results of evaluations 6-1 to 6-3 for Examples 27 to 41 and Comparative Examples 7 to 8. The evaluation results of evaluations 4-1 to 4-10 are shown in Tables 10-1 and 10-2. Further, the evaluation results of evaluations 5-1 to 5-3 are shown in Table 11.

10 Charging member 11 Photosensitive drum 12 Dirt 13 Power supply 14 Earth 20 Surface layer 21 Charging member 22 Photosensitive drum 23 Positive polarity ions 24 Negative charge 31 Surface layer 32 Core metal 33 Conductive resin layer

Claims (20)

An electrophotographic conductive member having a conductive support and a surface layer formed on the conductive support.
The surface layer has a three-dimensionally continuous skeleton and has pores communicating in the thickness direction, and an arbitrary 150 μm square region on the surface of the surface layer is photographed, and the region is photographed. When it is divided into 60 equal parts vertically and 60 equal parts horizontally and divided into 3,600 squares, the number of squares containing through holes is 100 or less.
The skeleton is non-conductive and
The skeleton is composed of a plurality of resin particles bonded to each other via a neck.
The resin particles contain a radiation-disintegrating type resin and
The average value D1 of the equivalent circle diameters of the resin particles is 0.1 μm or more and 20 μm or less.
A conductive member for electrophotographic feature. The conductive member for electrophotographic according to claim 1, wherein the glass transition temperature Tg of the radiation decay type resin is −150 ° C. or higher and 100 ° C. or lower. The electrophotograph according to claim 1 or 2, wherein the radiation-disintegrating resin is selected from the group consisting of polyisobutylene, poly-α-methylstyrene, polybutylmethacrylate, polyisobutylmethacrylate, and polyacetal. Conductive member for. The conductive member for electrophotographic according to any one of claims 1 to 3, wherein the average value D2 of the equivalent circle diameter of the cross section of the neck is 0.1 times or more and 0.7 times or less of the average value D1. .. The conductive member for electrophotographic according to any one of claims 1 to 4, wherein the surface layer has a thickness of 1 μm or more and 30 μm or less. The conductive member for electrophotographic according to any one of claims 1 to 5, wherein the volume resistivity of the surface layer is 1 × 10 ¹² Ω · cm or more and 1 × 10 ^{17 Ω · cm or less.} The conductive member for electrophotographic according to any one of claims 1 to 6, wherein the surface layer has a porosity of 20% or more and 80% or less. A conductive member for electrophotographic having a conductive support, an intermediate layer, and a surface layer in this order.
The surface layer has a three-dimensionally continuous skeleton and has pores communicating in the thickness direction.
A through hole is included when an arbitrary 150 μm square region on the surface of the surface layer is photographed and the region is divided into 60 equal parts vertically and 60 equal parts horizontally and equally divided into 3,600 squares. The number of squares is 100 or less,
The skeleton is non-conductive and
The skeleton is composed of a plurality of resin particles bonded to each other via a neck.
The average value D1 of the equivalent circle diameters of the resin particles is 0.1 μm or more and 20 μm or less, and
The intermediate layer is a conductive member for electrophotographic, which contains a radiation-disintegrating type resin and is non-conductive. The conductive member for electrophotographic according to claim 8, wherein the volume resistivity of the intermediate layer is 1 × 10 ¹² Ω · cm or more and 1 × 10 ^{17 Ω · cm or less.} The conductive member for electrophotographic according to claim 9, wherein the volume resistivity of the intermediate layer is 1 × 10 ¹⁵ Ω · cm or more and 1 × 10 ^{17 Ω · cm or less.} The conductive member for electrophotographic according to any one of claims 8 to 10, wherein the radiation-disintegrating type resin is an acrylic resin having a structural unit represented by the formula (1).

In formula (1), R ¹ represents a hydrocarbon group having 1 to 6 carbon atoms. The conductive member for electrophotographic according to claim 11, wherein R ¹ is a linear or branched alkyl group having 2 or more and 6 or less carbon atoms. The electrophotographic conductive member according to claim 11 or 12, wherein R ¹ is at least one selected from the group consisting of the groups represented by the following formulas (2) to (5).
(2) -C (CH ₃ ) ₃ ,
(3) -CH (CH ₃ ) ₂ ,
(4) -CH (CH ₃ ) -C (CH ₃ ) ₃ ,
(5) -C (CH ₃ ) _2- CH (CH ₃ ) ₂ . The conductive member for electrophotographic according to any one of claims 11 to 13, wherein R ¹ is −C (CH ₃ ) _3. The radiation-disintegrating type resin is a tertiary butyl polymethacrylate, methyl polymethacrylate, ethyl polymethacrylate, butyl polymethacrylate, isobutyl polymethacrylate, isopropyl polymethacrylate, butyl methacrylate-isobutyl methacrylate copolymer. The electrophotograph according to any one of claims 8 to 10, which is selected from the group consisting of a butyl methacrylate-ethyl methacrylate copolymer, polyalphamethylstyrene, polycyclohexylmethacrylate, and polyacetal. Conductive member for. The conductive member for electrophotographic according to any one of claims 8 to 15 , wherein the thickness of the intermediate layer is 1 μm or more and 5 μm or less. The conductive member for electrophotographic according to any one of claims 8 to 16 , wherein the resin particles constituting the skeleton include a radiation-disintegrating type resin. The conductive member for electrophotographic according to any one of claims 1 to 17 , wherein the conductive member includes a rigid body structure that protects the surface layer. A process cartridge that is detachably configured on the main body of an electrophotographic apparatus and includes the conductive member according to any one of claims 1 to 18. An electrophotographic apparatus comprising the conductive member according to any one of claims 1 to 18.

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