JP4341640B2 - Conductive roll for electrophotographic equipment and method for producing the same - Google Patents

Description

The present invention is a shall relates to a conductive roll and a manufacturing method thereof for electrophotographic apparatus.

  In recent years, electrophotographic apparatuses such as copying machines, printers, and facsimiles that employ an electrophotographic system have been widely used. In these electrophotographic apparatuses, a photosensitive drum is usually incorporated. Various conductive rolls such as a developing roll, a charging roll, a toner supply roll, and a transfer roll are disposed around the photosensitive drum.

  In the electrophotographic apparatus, recently, methods such as a contact development method and a contact charging method have become mainstream. In these methods, for example, a developing roll and a charging roll are used as follows.

  That is, in the contact development method, the surface of the developing roll on which the toner layer is formed is brought into direct contact with the surface of the photosensitive drum, thereby causing the toner to adhere to the latent image on the surface of the photosensitive drum.

  In the contact charging method, the surface of the charging roll is brought into direct contact with the surface of the photosensitive drum, and the surface of the photosensitive drum is charged by discharging the charging roll.

  Therefore, when a conductive roll is used as a developing roll, excellent toner transportability and the like are required, and when it is used as a charging roll, excellent chargeability for a photosensitive drum is required.

  In order to satisfy these required characteristics, conventionally, the surface of a roll has been roughened in a conductive roll such as a developing roll or a charging roll.

  For example, Patent Document 1 is a document relating to a developing roll, which discloses a developing roll whose surface is roughened by dispersing silica particles in the outermost resin layer of the roll. Yes.

  In addition, although patent document 2 is not the literature regarding an electroconductive roll, the same literature describes the insulator for multilayer wiring boards containing black and colored pigments (fine particles) such as carbon black and phthalocyanine pigments. Thus, a method of forming a conduction hole such as a through hole or a via hole by irradiating a laser beam is disclosed.

  Further, for example, Patent Document 3 is a document related to a charging roll. In this document, the surface of a rubber layer is polished with an abrasive to have a surface roughness of about 0.5 to 10 μm. In addition, a charging roll coated with a polyurethane resin is disclosed.

JP 2002-296897 A (paragraph 0002, paragraph 0034) JP 2003-86953 A (claims, examples, etc.) JP-A-9-160354 (Claims etc.)

  However, when the conventionally known roughening technique is applied to roughen the roll surface of the conductive roll, there are the following problems.

  That is, in the conventional developing roll, a large number of roughness forming particles such as silica particles are dispersed in the resin layer. This kind of roughness-forming particles tends to aggregate in the process of forming the resin layer. Therefore, there is a problem that it is difficult to obtain a uniform rough surface. If the surface roughness of the developing roll varies, the toner transportability and the like are likely to be uneven due to this.

  Furthermore, the surface of the resin layer is roughened by making the portion where the roughness forming particles are present convex and the portion not present being concave.

  Therefore, when the toner is transported, the hard convex portions on the surface of the resin layer tend to apply stress to the toner and cause the toner to deteriorate, which tends to cause a reduction in image quality. In particular, this kind of deterioration in image quality becomes prominent during long-term use of the developing roll.

  On the other hand, a conventional charging roll has a roll surface roughened by mechanical polishing using an abrasive. Therefore, there is a problem that it is difficult to obtain a uniform rough surface. If the surface roughness of the charging roll varies, the contact with the photosensitive drum becomes uneven due to this, and the discharge state also becomes unstable, causing uneven charging on the photosensitive drum and uneven image. It becomes easy.

  Further, slip-through toner, toner external additives (such as silica) and the like are likely to adhere to local recesses and protrusions on the roll surface. In particular, especially during long-term use, image quality deterioration corresponding to the uneven adhesion tends to occur.

  Thus, the roughened state of the roll surface greatly affects the performance of the conductive roll. Therefore, a conductive roll that can easily obtain a uniform rough surface is desired.

Therefore, the problem to be solved by the present invention is to provide a conductive roll for electrophotographic equipment, and a method for producing the same, in which a uniform rough surface can be easily obtained as compared with the prior art.

In order to solve the above problems, the electroconductive roll for electrophotographic equipment according to the present invention includes an outermost layer including an organic polymer containing at least a light-absorbing dye on the outermost periphery of the roll, and the surface of the outermost layer includes the light. The gist of the invention is that it has a large number of holes formed by irradiation with laser light containing a wavelength that is absorbed by the absorbing dye .

  At this time, the light absorbing dye preferably has an effective absorption wavelength in the near infrared region having a wavelength of 500 to 1200 nm.

The light absorbing dye preferably contains at least one or more selected from phthalocyanine dyes, immonium dyes, aminium dyes, naphthalocyanine dyes, and dioxazine dyes.
The electroconductive roll for electrophotographic equipment is preferably a developing roll or a charging roll.

On the other hand, the method for producing a conductive roll for electrophotographic equipment according to the present invention includes a first step of forming an outermost layer containing an organic polymer containing at least a light-absorbing dye on the outermost periphery of the roll, and a surface of the outermost layer. And a second step of forming a large number of holes by irradiating a laser beam containing a wavelength absorbed by the light-absorbing dye.

The electroconductive roll for electrophotographic equipment according to the present invention contains a light-absorbing dye in the outermost organic polymer. Therefore, the outermost layer of the surface, shine containing a wavelength that is absorbed by the light absorbing dye laser light irradiation lever, heat generated by the light-absorbing dye must be present in the irradiated area, than the conventional with a clear contour Holes are easily formed. Therefore, since roughness can be imparted using such holes, it is easy to obtain a relatively uniform rough surface.

Therefore, for example, when the electrophotographic apparatus conductive roll according to the present invention is applied to a developing roll, the outermost layer is roughened in order to roughen the outermost layer surface like a conventional developing roll. There is substantially no need to add forming particles.

  Therefore, aggregation due to roughness forming particles does not occur as in the prior art, and the toner transportability, toner chargeability, etc. are excellent.

  Further, the surface hardness does not increase due to the roughness forming particles, and the roughness forming particles do not give stress to the toner during toner conveyance. Therefore, even when used for a long time, it is difficult to deteriorate the toner, and it is possible to maintain a good image quality for a long time.

Further, for example, when the electroconductive apparatus conductive roll according to the present invention is applied to a charging roll, it can be uniformly contacted with the photosensitive drum, so that the discharge state is stabilized and uneven charging is less likely to occur.

  Further, if the surface of the outermost layer is uniform and rough, it is difficult for sticking-through toner or toner external additives to adhere, so that it is possible to suppress deterioration in image quality due to uneven adhesion.

  Here, when the light-absorbing dye has an effective absorption wavelength in the near-infrared region having a wavelength of 500 to 1200 nm, the hole portion is utilized using a laser beam having an effective absorption wavelength in the near-infrared region. Can be formed.

  When the light absorbing dye contains at least one or more selected from phthalocyanine dyes, immonium dyes, aminium dyes, naphthalocyanine dyes and dioxazine dyes, the near infrared region Since it has an effective absorption wavelength, it is easy to absorb laser light, and a hole can be formed with relatively high processing accuracy.

On the other hand, in the method for producing a conductive roll for electrophotographic equipment according to the present invention, in the first step, after forming the outermost layer containing an organic polymer containing at least a light-absorbing dye on the outermost periphery of the roll, in the second step The surface of the outermost layer is irradiated with laser light including a wavelength that is absorbed by the light-absorbing dye to form a large number of holes.

  For this reason, at the laser light irradiation site, the light absorbing dye absorbs the laser light, and heat generated thereby forms a hole having a clearer contour than before. And by forming many such holes, a relatively uniform rough surface is formed on the surface of the outermost layer.

Therefore, according to the method for producing a conductive roll for electrophotographic equipment according to the present invention, the electroconductive roll for electrophotographic equipment according to the present invention having the above-described effects can be obtained.

In addition, the method for producing a conductive roll for electrophotographic equipment according to the present invention has a relatively high degree of freedom in controlling the distribution density of the holes and the size of the holes. Therefore, there is an advantage that the surface roughness of the outermost layer can be controlled relatively easily and accurately as compared with the case where roughness forming particles are used.

Hereinafter, the electroconductive roll for electrophotographic equipment according to the present embodiment (hereinafter, also referred to as “main roll”), and the method for manufacturing the electroconductive roll for electrophotographic equipment according to the present embodiment (hereinafter, “the present manufacturing method”). Will be described in detail.

1. Main roll The main roll has a specific outermost layer on the outermost periphery of the roll. Specifically, if this roll has one layer, this layer corresponds to the outermost layer of this roll. Moreover, if this roll has a laminated structure in which two or more layers are laminated, the layer located on the outermost circumference of the roll corresponds to the outermost layer of this roll.

  The specific configuration of the roll is, for example, the outer periphery of a conductive shaft (a metal core made of a solid metal, a metal cylinder hollowed out inside, or a metal plated body thereof) The outer shaft has one outermost layer, or one or more inner layers (for example, a conductive elastic layer) on the outer periphery of the shaft, and the outermost layer (for example, a film) on the outer periphery. Examples of the configuration can be given.

  The thickness of the outermost layer, the thickness of the inner layer, the laminated structure, etc. can be appropriately selected in consideration of the installation space inside the electrophotographic apparatus incorporating the roll, the type of the electrophotographic apparatus, the use of the roll, etc. it can.

  In this roll, the outermost layer contains an organic polymer containing at least a light-absorbing dye.

  Specific examples of the organic polymer include silicone resins, acrylic resins, urethane resins, polyester resins, polyamide resins, fluorine resins, polyimide resins, polyamideimide resins, amino resins, Polyethersulfone resins, resins obtained by copolymerizing fluorine and / or silicone with these resins, silicone rubber, acrylic rubber, urethane rubber, nitrile rubber, fluorine rubber, natural rubber, butyl rubber, ethylene-propylene rubber, polybutadiene rubber Examples thereof include isoprene rubber and styrene-butadiene rubber. These may be contained alone or in combination of two or more.

  Among these organic polymers, for example, a polymer having transparency to light having a wavelength that can be absorbed by the contained light-absorbing dye is preferably used in order to facilitate formation of pores by the production method described later. be able to.

  Specifically, for example, transparent polymers such as silicone resins, acrylic resins, urethane resins, silicone rubbers, acrylic rubbers, and urethane rubbers can be exemplified as suitable ones.

  Here, the light absorbing pigment contained in the organic polymer mainly has a function of converting the absorbed light into heat. Therefore, when the light absorbing dye is irradiated with light having a wavelength that can be absorbed, the light absorbing dye converts the absorbed light into heat and can generate heat.

Therefore, the outermost layer surface, the light such as including a wavelength that is absorbed by the light absorbing dye laser beam irradiation shines lever, heat generated by the light-absorbing dye must be present in the irradiated portion, a conventionally clear contour The hole part which it has is easy to be formed.

  The said light absorption pigment | dye may be contained 1 type (s) or 2 or more types in the organic polymer. The light-absorbing dye is preferably soluble or finely dispersed in an organic solvent and soluble or finely dispersed in an organic polymer. This is because it becomes easier to form pores having a clearer contour than in the prior art because it is easily dispersed in the organic polymer at the molecular level.

  Specifically, the light-absorbing dye has a wide variety of processing machine lenses, a wide processing area, and capable of high-speed processing, for example, near-infrared light having a wavelength of 500 to 1200 nm. So-called near infrared absorbing dyes having an effective absorption wavelength in the region are preferred.

  More specifically, examples of the light-absorbing dye include phthalocyanine dyes, immonium dyes, aminium dyes, naphthalocyanine dyes, dioxazine dyes, and the like. These may be contained alone or in combination of two or more.

  Among these, the light-absorbing dye is selected from phthalocyanine dyes and immonium dyes from the viewpoints of excellent absorption of wavelengths in the near infrared region, fine dispersion in organic polymers and excellent solubility, among others. It is good to contain at least 1 type or 2 types or more.

  The phthalocyanine dye is marketed, for example, under the trade name “EEX Color Series” by Nippon Shokubai Co., Ltd. The immonium dye is marketed, for example, by Nippon Carlit Co., Ltd. under the trade name “CIR series”. The aminium dye is marketed, for example, by Nippon Kayaku Co., Ltd. under the trade name “KAYASORB series”. The naphthalocyanine dye is marketed, for example, under the trade name “YKR series” by Yamamoto Kasei Co., Ltd.

  Whether or not the outermost layer in this roll contains a light-absorbing dye is determined by analyzing and analyzing the eluate eluted from the outermost layer of the roll using, for example, NMR, GC-MS analysis, etc. It can be examined by specifying. When forming a hole by a laser processing technique, not all of the light-absorbing dye contained in the outermost layer is used for forming the hole, and those not used remain in the outermost layer. Because.

  The content of the light absorbing dye contained in the outermost layer is not particularly limited. However, when the content of the light-absorbing dye is excessively increased, the production cost of the present roll tends to increase. On the other hand, when the content of the light-absorbing dye is excessively low, there is a tendency that it becomes difficult to form the hole using the light-absorbing dye by the laser processing technique. Accordingly, the content of the light-absorbing dye is preferably selected in consideration of these.

  As a preferable upper limit value of the content of the light-absorbing dye contained in the outermost layer, specifically, for example, 40, 30, 20, 15, with respect to 100 parts by weight of the organic polymer constituting the outermost layer. An example is 10 parts by weight. On the other hand, specific examples of preferable lower limit values that can be combined with these preferable upper limit values include 0.1, 0.3, and 0.5 parts by weight.

  Moreover, in the said outermost layer, as long as it exists in the range with the effect of this invention, 1 type (s) or 2 or more types of other additives other than the said light absorption pigment | dye are added as needed. Also good. Specific examples of other additives include carbon black, pigments, conductive agents (ionic conductive agents, electronic conductive agents), antioxidants, curing agents, anti-aging agents, fillers, flame retardants, oils, and the like. Can be illustrated.

  In particular, when carbon black is further contained, it becomes easy to efficiently absorb laser light, so that the processing accuracy of the hole can be improved.

  In this case, as a preferable upper limit value of the carbon black content, specifically, for example, 10, 5, 3 parts by weight, etc. with respect to 100 parts by weight of the organic polymer constituting the outermost layer. Can do. On the other hand, specific examples of preferable lower limit values that can be combined with these preferable upper limit values include 0.1, 0.5, and 1 part by weight.

  Further, the carbon black / light absorbing pigment (weight ratio) in the outermost layer is, for example, preferably 100, 50, 20 or the like as a preferable upper limit value from the viewpoint of easily exerting the above effect. It can be illustrated. On the other hand, specific examples of preferable lower limit values that can be combined with these preferable upper limit values include 0.01, 0.1, 1 and the like.

  This roll has many holes on the surface of the outermost layer described above. As the form of the hole, substantially cylindrical (including an elliptical opening), substantially hemispherical, substantially polygonal columnar, substantially conical (top direction is the inner side), substantially polygonal pyramid (the top direction is the inner side) ) And the like. One or more of these forms may be included. Preferably, from the viewpoint of ease of formation, a form such as a substantially cylindrical shape or a substantially hemispherical shape is suitable.

  Specific examples of the preferable upper limit of the opening diameter of the hole from the viewpoint of obtaining a surface roughness having suitable toner transportability include 200, 160, 120 μm, and the like. . Specific examples of preferable lower limit values that can be combined with these preferable upper limit values include 20, 30, 40, and 50 μm.

  The “opening diameter of the hole” refers to an average value of the diameters of the respective openings measured with respect to 10 arbitrarily selected holes by observing the outermost surface of the roll with an electron microscope.

  The hole may be a non-through hole that does not penetrate the outermost layer or a through hole that penetrates the outermost layer as long as the hole has an opening on the surface. The depth of the hole is, for example, a surface roughness that can express good toner transportability when used as a developing roll, and a surface roughness that can express good charging properties when used as a charging roll. In view of the above, specific examples of the preferable upper limit include 20, 15, 10 μm, and the like. Specific examples of preferable lower limit values that can be combined with these preferable upper limit values include 1, 2, 3 μm, and the like.

  The “depth of the hole” means that the outermost layer is cut in the thickness direction, the cross section thereof is observed with an electron microscope, and the distance from the outermost surface to the deepest portion measured for 10 arbitrarily selected holes is measured. Refers to the average value.

  The opening edge of the hole is preferably formed so as not to overlap with the opening edge of the adjacent hole. As the distance between the opening edges of adjacent holes, for example, when used as a developing roll, a surface roughness capable of expressing good toner transportability is obtained, and when used as a charging roll, good chargeability is expressed. Specific examples of the preferable upper limit value from the standpoint of obtaining a surface roughness that can be obtained include 50, 25, 10 μm, and the like. Specific examples of preferable lower limit values that can be combined with these preferable upper limit values include 0.5, 1, 3 μm, and the like.

  The "distance between the opening edges of adjacent holes" is the average of the distances between the opening edges measured at 10 locations between the arbitrarily selected opening edges by observing the outermost layer surface with an electron microscope. Points to the value.

  In the present roll, the holes are preferably arranged regularly from the viewpoint of making the surface roughness of the outermost layer of the roll uniform over the entire surface. Specifically, as the arrangement of the holes, for example, a regular arrangement in the roll circumferential direction, for example, the pitch between the holes is made constant in the roll circumferential direction, or the pitch between the holes is a roll axis. The direction (longitudinal direction) is made constant, such as a regular arrangement in the roll axis direction, an arrangement by a combination thereof, or a pitch between the holes is made constant in a direction inclined with respect to the roll axis direction. For example, a regular arrangement in a direction inclined with respect to the roll axis direction can be exemplified.

  The surface of the outermost layer is roughened by the numerous holes described above, but the surface roughness of the outermost layer is preferable from the viewpoint of excellent toner transportability, charging property, and the like. Specific examples of the upper limit value include 20, 16, and 12 μm. Specific examples of preferable lower limit values that can be combined with these preferable upper limit values include 2, 3, 4 μm, and the like.

  The “surface roughness” refers to the ten-point average roughness Rz measured according to JIS B0601: 1994.

  A specific method for forming these holes will be described later in the section “2. Production method”.

  As described above, the outermost layer surface of the present roll is roughened by having a large number of holes on the outermost layer surface. That is, this roll does not mean that the surface of the outermost layer is roughened by mainly using the convex portions formed by dispersing the roughness-forming particles in the outermost layer.

  Therefore, the present roll does not have a substantial number of convex portions on the outermost layer surface, but if it is within the range where the effects of the present invention are exerted, the outermost layer surface has additives, impurities. There may be convex portions or the like due to the above.

  The outermost layer of this roll has been described above. In addition, when this roll has a laminated structure, the material for forming the inner layer may be appropriately selected in consideration of the specific application of the roll (developing roll, charging roll, etc.).

  Specific examples of the material for forming the inner layer include those containing a conductive agent (electronic conductive agent and / or ionic conductive agent) in the following main materials.

  That is, specific examples of the main material include silicone rubber, ethylene-propylene-diene rubber (EPDM), acrylonitrile-butadiene rubber (NBR), hydrogenated acrylonitrile-butadiene rubber (H-NBR), and styrene-butadiene. Rubber (SBR), butadiene rubber (BR), isoprene rubber (IR), acrylic rubber (ACM), chloroprene rubber (CR), urethane rubber, fluorine rubber, hydrin rubber (ECO, CO), polyurethane elastomer, natural rubber ( NR) and the like. These may be used alone or in combination.

  In particular, when the present roll is used as a developing roll, the main materials described above are used from the viewpoints of flexibility that can reduce stress on the toner and excellent low compression set for a photosensitive drum or a layer forming blade. Examples of suitable materials include silicone rubber, polyurethane-based elastomer, and butadiene rubber.

  Further, when this roll is used as a charging roll, hydrin rubber, nitrile rubber, polyurethane-based elastomer and the like are suitable as the main material from the viewpoint of having high ionic conductivity that uniformly imparts a charge to the photosensitive drum. Can be exemplified.

When the present roll is used as a developing roll, the content of the conductive agent is generally such that the volume resistivity of the inner layer is preferably 10 ² to 10 ¹² Ω · cm, more preferably 10 ³ to 10 ⁸ Ω · cm. What is necessary is just to adjust suitably so that it may become in the range. When the present roll is used as a charging roll, the volume resistivity of the inner layer is usually preferably in the range of 10 ² to 10 ¹² Ω · cm, more preferably 10 ³ to 10 ¹⁰ Ω · cm. What is necessary is just to adjust suitably.

  In addition to the conductive agent, the material for forming the inner layer may be a filler, an extender, a reinforcing agent, an activator, a processing aid, a vulcanizing agent, a vulcanization accelerator, a crosslinking agent, a crosslinking aid, if necessary. One or more various additives such as antioxidants, plasticizers, ultraviolet absorbers, pigments, silicone oils, lubricants and auxiliaries may be appropriately contained.

  The proportion of the additive may be appropriately selected from conventionally known blending proportions so that various additives can achieve their purpose. Moreover, when it has two or more inner layers, each inner layer may be the same material and composition, and a different material and composition may be sufficient as it.

  Although the thickness of the said inner layer is not necessarily limited, Usually, it should just adjust suitably so that it may preferably become in the range of 0.5-10 mm, More preferably, it is 1-6 mm.

2. This manufacturing method This manufacturing method is a method which can manufacture this roll which has the above-mentioned composition, and includes the following 1st processes and 2nd processes at least. Hereinafter, it demonstrates in order.

2.1 First Step In this production method, the first step is a step of forming an outermost layer containing an organic polymer containing at least a light-absorbing dye on the outermost periphery of the roll.

  Here, when manufacturing this roll having one layer, as the first step, specifically, the above light-absorbing dye is applied to the surface of the conductive shaft on which an adhesive, a primer or the like is arbitrarily applied. And a method of extruding a composition containing at least the organic polymer, the conductive shaft is coaxially installed in a hollow part of a roll molding die, the composition is injected, and heated and cured. Thereafter, a method of demolding, roll coating a composition containing at least the light absorbing dye, the organic polymer, and an organic solvent (MEK: methyl ethyl ketone, acetone, toluene, alcohol, etc.) on the surface of the conductive shaft. Examples thereof include a method of coating by a method and the like and forming by drying.

  On the other hand, when manufacturing this roll having a laminated structure, specifically, as the first step, for example, the following method can be exemplified. That is, first, the roll before forming the outermost layer by extruding or molding one layer or two or more layers of the inner layer forming material described above on the surface of the same conductive shaft. Pre-form the body.

  Subsequently, a method of extruding or molding a composition containing at least the light absorbing dye and the organic polymer on the surface of the formed roll body in the same manner as described above, the light absorbing dye, Examples thereof include a method in which a composition containing at least the organic polymer and the organic solvent is applied by a roll coating method and dried.

  At this time, in this step, the content of the light-absorbing dye contained in the composition used for forming the outermost layer is, as a preferable upper limit, specifically, for example, contained in the composition. For example, 40, 30, 20, 15, 10 parts by weight and the like can be exemplified with respect to 100 parts by weight of the organic polymer. On the other hand, specific examples of preferable lower limit values that can be combined with these preferable upper limit values include 0.1, 0.3, and 0.5 parts by weight.

  Moreover, the said composition may contain 1 type, or 2 or more types of said additives, such as carbon black, as needed.

  By passing through the first step described above, the outermost layer (hole not formed) containing an organic polymer containing at least a light-absorbing dye can be formed on the outermost periphery of the roll.

2.2 Second Step In this manufacturing method, the second step is a step of irradiating the surface of the outermost layer formed through the first step with a laser beam to form a large number of holes.

  In this step, at the site irradiated with the laser beam, the light absorbing dye contained in the outermost layer absorbs the laser beam, and a hole is formed by the heat generated thereby.

  Here, the light-absorbing dye is easily dispersed at the molecular level in the organic polymer. Therefore, compared with the case where laser processing is performed mainly using a pigment composed of fine particles, a hole having a clear outline (for example, the opening edge of the hole is clear) is easily formed.

  The laser beam used in this step only needs to include a wavelength that is absorbed by the light-absorbing dye. Specifically, for example, if the light-absorbing dye is a near-infrared-absorbing dye, the laser light may include a wavelength in the near-infrared region of a wavelength of 350 to 1500 nm, preferably 500 to 1200 nm.

  Specific examples of lasers that generate such laser light include Nd-YAG lasers, excimer lasers, and UV lasers. These may be used alone or in combination of two or more.

  As a method for irradiating the laser beam, specifically, for example, the following method can be exemplified. That is, for example, a plurality of lens systems for converging laser light into minute dots are arranged linearly along the roll axis direction of the roll body on which the outermost layer is formed, and the laser light is converged into dots. When a large number of dot-like portions are scattered on the surface of the outermost layer in a straight line from the one end edge to the other end edge along the roll axis direction, a plurality of holes are formed at the same time in the dotted portions. be able to.

  Further, when the roll body is intermittently rotated around the roll axis and laser light is intermittently irradiated in synchronization with the rotation, a large number of holes can be formed on the outermost layer surface.

  In addition, by adjusting the lens system, the point portions where the laser light is converged in a point shape are made to have a constant pitch, and further, the intermittent rotation of the roll body is made to have a constant angle, the holes are surrounded. It becomes possible to arrange regularly in the direction and the axial direction.

  In addition, for example, one laser beam is scanned along the roll axis direction of the roll body on which the outermost layer is formed, the direction inclined with respect to the roll axis direction, and the laser beam is interrupted during the scanning process. May be irradiated.

  At this time, the size of the hole to be formed may be set by appropriately adjusting the output of the laser beam, the irradiation time, and the like.

  By passing through the second step described above, a large number of holes can be formed on the surface of the outermost layer formed through the first step.

  According to the manufacturing method, the main roll can be obtained. In addition, this manufacturing process may include, for example, a step of polishing the outermost layer surface as necessary before and after the second step.

  Further, before and after the second step, for example, a surface treatment for improving the releasability with respect to the toner may be performed on the outermost layer surface as necessary. In this case, it is possible to reduce image quality deterioration due to toner adhesion on the surface of the obtained roll.

  Specific examples of the surface treatment include fluoride treatment, chlorine treatment, UV treatment, plasma treatment, corona treatment, isocyanate treatment, and siloxane treatment. These surface treatments may be performed singly or in combination of two or more.

  Hereinafter, the present invention will be described in detail using examples. Hereinafter, the case where the present invention is applied to a developing roll and a charging roll will be exemplified.

<Development roll>
1. Production of Developing Roll According to Examples and Comparative Examples (Example 1G)
As shown below, a conductive shaft, a material for forming a conductive elastic layer serving as an inner layer, and a material for forming an outermost layer were prepared. And using these, the developing roll which laminated | stacked the outermost layer which consists of a conductive elastic layer and a coating film on the outer periphery of the conductive shaft in this order was produced.

<Conductive shaft>
An iron solid cylindrical conductive shaft having an outer diameter of 8 mm and a length of 350 mm was prepared.

<Material for forming conductive elastic layer>
Conductive silicone rubber (manufactured by Shin-Etsu Chemical Co., Ltd., “X34-264A / B”) was kneaded with a kneader to prepare a material for forming a conductive elastic layer as an inner layer.

<Outermost layer forming material>
After kneading 100 parts by weight of a urethane resin (manufactured by Nippon Polyurethane Co., Ltd., “Nipporan 2304”) and 1 part by weight of immonium dye A (manufactured by Nippon Carlit Co., Ltd., “CIR-1080”) with a ball mill, The material for forming the outermost layer was prepared by adding 400 parts by weight of MEK, mixing, and stirring.

<Preparation of developing roll>
The material for forming the conductive elastic layer was poured into a cylindrical mold in which the conductive shaft was coaxially set, heated at 200 ° C. for 30 minutes, cooled and demolded. Thereby, a roll body having one conductive elastic layer (thickness 4 mm, length 240 mm) on the outer periphery of the conductive shaft was produced.

  Subsequently, after forming the outermost layer forming material on the outer periphery of the conductive elastic layer of the roll body by a roll coating method, the outermost layer (thickness 10 μm) made of a coating film was formed by drying (curing). .

  Next, the surface of the outermost layer was irradiated with laser light (laser etching) to form a large number of holes. At this time, the holes were formed so that the opening edges of the adjacent holes did not overlap each other. Also, a constant pitch in the roll circumferential direction and the roll axial direction (both the distance between the opening edges of the holes adjacent in the roll circumferential direction and the distance between the opening edges of the holes adjacent in the roll axial direction are 5 μm) I went to become.

  At this time, the laser light irradiation conditions were as follows: laser type: Nd-YAG laser, output: 22 A, frequency: 30 kHz, irradiation speed: 2400 mm / sec.

  As a result, a large number of holes (opening diameter 80 μm, depth 3 μm) having a substantially concave cross section were formed on the outermost layer surface.

  When the 10-point average roughness (Rz) of the formed outermost layer surface was measured in accordance with JIS B0601: 1994, Rz was 10.1 μm. For the measurement of Rz, a contact surface roughness meter (manufactured by Tokyo Seimitsu Co., Ltd., “Surfcom 1400D”) was used. Moreover, this measurement was performed 5 times, and the difference between the maximum value and the minimum value of Rz obtained was regarded as roughness variation. As a result, the roughness variation was 0.1 μm.

  As described above, the developing roll according to Example 1G was produced.

(Example 2G)
In preparation of the developing roll according to Example 1G, when preparing the outermost layer forming material, acrylic resin A (manufactured by Sumitomo Chemical Co., Ltd., “LG6A”) was used instead of urethane resin, immonium A developing roll according to Example 2G was prepared in the same manner except that the system dye B (manufactured by Nippon Carlit Co., Ltd., “CIR-1081”) was used. The hole on the outermost layer surface had an opening diameter of 85 μm and a depth of 5 μm. The outermost layer had a surface roughness Rz of 9.8 μm and a roughness variation of 0.1 μm.

(Example 3G)
In preparing the developing roll according to Example 1G, except that the outermost layer forming material was prepared, acrylic resin B (manufactured by Negami Kogyo Co., Ltd., “Paraklon W197C”) was used instead of the urethane resin. Similarly, a developing roll according to Example 3G was produced. The hole on the outermost layer surface had an opening diameter of 80 μm and a depth of 4 μm. The outermost layer had a surface roughness Rz of 8.8 μm and a roughness variation of 0.1 μm.

(Example 4G)
In the production of the developing roll according to Example 1G, when the outermost layer forming material was prepared, a polyester resin (“Byron SS30” manufactured by Toyobo Co., Ltd.) was used instead of the urethane resin. A developing roll according to Example 4G was produced in the same manner except that immonium dye B was used instead of system dye A. The hole on the outermost layer surface had an opening diameter of 82 μm and a depth of 4 μm. The outermost layer had a surface roughness Rz of 8.5 μm and a roughness variation of 0.2 μm.

(Example 5G)
In preparing the developing roll according to Example 1G, when preparing the outermost layer forming material, the acrylic resin B was used instead of the urethane resin, and the phthalocyanine dye was used instead of 1 part by weight of the immonium dye A. (The development roll according to Example 5G was produced in the same manner except that 10 parts by weight of “TX-EX-910B” manufactured by Nippon Shokubai Co., Ltd. was used. The diameter was 85 μm, the depth was 3 μm, and the surface roughness Rz of the outermost layer was 9.0 μm, and the roughness variation was 0.1 μm.

(Example 6G)
In preparing the developing roll according to Example 1G, when preparing the outermost layer forming material, except for using acrylic resin A instead of urethane resin, and using 0.5 parts by weight of immonium dye A. In the same manner, a developing roll according to Example 6G was produced. The hole on the outermost layer surface had an opening diameter of 80 μm and a depth of 4 μm. The outermost layer had a surface roughness Rz of 9.6 μm and a roughness variation of 0.1 μm.

(Example 7G)
In the preparation of the developing roll according to Example 1G, when preparing the outermost layer forming material, the same except that the acrylic resin A was used instead of the urethane resin, and 30 parts by weight of immonium dye A was used. Thus, a developing roll according to Example 7G was produced. The hole on the outermost layer surface had an opening diameter of 80 μm and a depth of 10 μm. Further, the outermost layer had a surface roughness Rz of 10.0 μm and a roughness variation of 0.1 μm.

(Example 8G)
In preparing the developing roll according to Example 1G, when preparing the outermost layer forming material, acrylic resin B was used instead of urethane resin, 1 part by weight of immonium dye A, and carbon black (Mitsubishi). A developing roll according to Example 8G was produced in the same manner except that 10 parts by weight of “MA100” manufactured by Chemical Co., Ltd. was used in combination. The hole on the outermost layer surface had an opening diameter of 100 μm and a depth of 5 μm. The surface roughness Rz of the outermost layer was 11.2 μm, and the roughness variation was 0.2 μm.

(Comparative Example 1G)
In the production of the developing roll according to Example 1G, when preparing the outermost layer forming material, immonium-based dye A is not used, and silica particles ("Silicia" manufactured by Fuji Silysia Chemical Co., Ltd.) are used as roughness forming particles. 450 ") 35 parts by weight, and further, except that 35 parts by weight of the carbon black was blended, the surface of the outermost layer was not irradiated with laser light, and no holes were formed at all. A developing roll according to 1G was prepared. The outermost layer had a surface roughness Rz of 12.1 μm and a roughness variation of 2.4 μm.

2. Evaluation of Each Developing Roll The following evaluations were performed on the produced developing rolls in order to examine the difference in performance due to the roughened state of the roll surface.

2.1 Roll surface hardness First, as reference data, the surface hardness of each developing roll was measured with an MD-1 hardness meter (manufactured by Kobunshi Keiki Co., Ltd., “Micro rubber hardness meter MD-1 type”) (N = 3)

2.2 Residual charge unevenness The residual charge unevenness was measured for each developing roll. That is, first, a corotron (charger) was installed along the axial direction of each developing roll. At this time, the distance between the core portion of the corotron and the surface of the outermost layer of the developing roll was set to 10 mm. The core of the corotron was connected to the negative side of the DC power source via a constant current control device (constant current set to -100 μA), and the positive side of the DC power source was grounded. The shield portion of the corotron was grounded together with the shaft of the developing roll. Then, with the developing roll rotated in the circumferential direction at a rotation speed of 70 rotations per minute, the surface of the outermost layer was charged by the corotron, and the outermost layer at a position rotated 90 degrees from the charging position in the rotation direction. The residual charge of was measured. This residual charge is measured by using a probe (potential detector) connected to a surface electrometer (Trek, Model 541) at 8.7 mm / s in the image area of the outermost layer along the axial direction of the developing roll. We went while moving at speed. At this time, the distance between the probe and the surface of the outermost layer was set to 1 mm. The image area is an area where a toner layer is formed, and is an intermediate part excluding a part up to 5 mm inward from both end edges of the outermost layer. Then, the difference between the maximum value and the average value of the measured residual charges was defined as residual charge unevenness [V]. The case where the residual charge unevenness was 20 V or less was determined to be acceptable, and the case where it exceeded 20 V was determined to be unacceptable.

2.3 Density unevenness The density unevenness was measured for each developing roll. That is, each developing roll was incorporated into a commercially available color laser printer (manufactured by Canon Inc., “Laser Shot LBP-2510”), and a black solid image was imaged in an environment of 20 ° C. × 50% RH. . Subsequently, the obtained images were visually checked for uneven density. As a result, a sample having no density unevenness was accepted, and a sample having density unevenness was rejected.

2.4 Fog Each developing roll was examined for the presence of initial fogging and durable fogging. That is, after performing the image printing described in “2.3 Density Unevenness” for 5000 sheets (A4 size), the density of the white background portion on the surface of the photosensitive drum is measured using a Macbeth densitometer. The presence or absence was examined.

  As a result, when the density was less than 0.15, the fogging phenomenon (the toner adhesion phenomenon on the white background portion of the photosensitive drum surface) hardly occurred and passed (double circles in the table described later). Show). In addition, when the concentration was 0.15 or more and less than 0.2, the fogging phenomenon was slightly occurred, but it was accepted as being within the allowable range (indicated by a circle in the table described later). Moreover, the density | concentration of 0.2 or more was set as the rejection (it shows by the cross mark in the table | surface mentioned later) because the clear fog phenomenon generate | occur | produced.

  On the other hand, the presence or absence of a durable fog phenomenon was examined and evaluated in the same manner as described above except that the above-described image extraction was performed in an environment of 32.5 ° C. × 85% RH.

  Table 1 shows a summary of the composition and evaluation results of the outermost layer forming material of each developing roll.

  According to Table 1, the following can be understood. That is, the developing roll according to Comparative Example 1G had large residual charge unevenness and non-uniform toner chargeability. This is presumed to be because the silica particles added as roughness-forming particles aggregate in the outermost layer of the roll and are dispersed non-uniformly.

  In addition, the developing roll according to Comparative Example 1G had density unevenness and a fog phenomenon remarkably occurred during long-term use. This is presumed that the outermost layer surface was roughened by unevenness due to the silica particles, and the convex portions due to the hard silica particles caused the toner to deteriorate due to stress applied to the toner, which caused the image quality to deteriorate. Is done.

  In contrast, the evaluation results of the developing rolls according to Examples 1G to 8G were all acceptable. As can be seen from the fact that the roughness variation of the outermost layer surface is small, a large number of holes are mainly formed by using a light-absorbing dye and a laser processing technique, so that the outermost layer surface is uniformly roughened. It is presumed that this is because According to the developing rolls according to Examples 1G to 8G, it can be confirmed that the toner chargeability and toner transportability are superior to those of the conventional rolls, the toner is hardly deteriorated, and the image quality is hardly deteriorated over a long period of time. It was.

<Charging roll>
1. Production of Charging Roll According to Examples and Comparative Examples (Example 1T)
As shown below, a conductive shaft, a material for forming a conductive elastic layer serving as an inner layer, and a material for forming an outermost layer were prepared. And using these, the charging roll which laminated | stacked the outermost layer which consists of a conductive elastic layer and a coating film on the outer periphery of the conductive shaft in this order was produced.

<Conductive shaft>
An iron solid cylindrical conductive shaft having an outer diameter of 8 mm and a length of 350 mm was prepared.

<Material for forming conductive elastic layer>
100 parts by weight of epichlorohydrin rubber (ECO) (“Epichromer CG102” manufactured by Daiso Corporation), 1 part by weight of stearic acid (“Lunac S-30” manufactured by Kao Corporation), and an ionic conductive agent (Lion) "TBAHS" manufactured by Co., Ltd. 1 part by weight, 2-mercaptoimidazoline (vulcanizing agent) (by Kawaguchi Chemical Industry Co., Ltd., "Axel 22S") 2 parts by weight, and acid acceptor (Kyowa Chemical Industry ( The material <T1> for forming a conductive elastic layer serving as an inner layer was prepared by kneading 5 parts by weight of “DHT-4A”) manufactured by the same company with a kneader.

<Outermost layer forming material>
After kneading 100 parts by weight of a urethane resin (manufactured by Nippon Polyurethane Co., Ltd., “Nipporan 2304”) and 1 part by weight of immonium dye A (manufactured by Nippon Carlit Co., Ltd., “CIR-1080”) with a ball mill, The material for forming the outermost layer was prepared by adding 400 parts by weight of MEK, mixing, and stirring.

<Preparation of charging roll>
The material for forming the conductive elastic layer <T1> was poured into a cylindrical mold in which the conductive shaft was coaxially set, heated at 170 ° C. for 30 minutes, cooled and demolded. Thereby, a roll body having one conductive elastic layer (thickness 4 mm, length 240 mm) on the outer periphery of the conductive shaft was produced.

  Subsequently, after forming the outermost layer forming material on the outer periphery of the conductive elastic layer of the roll body by a roll coating method, the outermost layer (thickness 10 μm) made of a coating film was formed by drying (curing). .

  Next, the surface of the outermost layer was irradiated with laser light (laser etching) to form a large number of holes. At this time, the holes were formed so that the opening edges of the adjacent holes did not overlap each other. Also, a constant pitch in the roll circumferential direction and the roll axial direction (both the distance between the opening edges of the holes adjacent in the roll circumferential direction and the distance between the opening edges of the holes adjacent in the roll axial direction are 5 μm) I went to become.

  At this time, the laser light irradiation conditions were as follows: laser type: Nd-YAG laser, output: 30 A, frequency: 30 kHz, irradiation speed: 2000 mm / second.

  As a result, a large number of holes (opening diameter 120 μm, depth 3 μm) having a substantially concave cross section were formed on the outermost layer surface.

  When the ten-point average roughness (Rz) of the formed outermost layer surface was measured according to JIS B0601: 1994, Rz was 8.2 μm. For the measurement of Rz, a contact surface roughness meter (manufactured by Tokyo Seimitsu Co., Ltd., “Surfcom 1400D”) was used. Moreover, this measurement was performed 5 times, and the difference between the maximum value and the minimum value of Rz obtained was regarded as roughness variation. As a result, the roughness variation was 0.1 μm.

  As described above, a charging roll according to Example 1T was produced.

Example 2T
In the preparation of the charging roll according to Example 1T, when the outermost layer forming material was prepared, acrylic resin A (manufactured by Sumitomo Chemical Co., Ltd., “LG6A”) was used instead of urethane resin, immonium A charging roll according to Example 2T was produced in the same manner except that the system dye B (manufactured by Nippon Carlit Co., Ltd., “CIR-1081”) was used. The hole on the outermost layer surface had an opening diameter of 110 μm and a depth of 5 μm. The outermost layer had a surface roughness Rz of 8.5 μm and a roughness variation of 0.1 μm.

Example 3T
In the preparation of the charging roll according to Example 1T, when the outermost layer forming material was prepared, an acrylic resin B (manufactured by Negami Kogyo Co., Ltd., “Paraklon W197C”) was used instead of the urethane resin. Similarly, a charging roll according to Example 3T was produced. The hole on the outermost layer surface had an opening diameter of 120 μm and a depth of 4 μm. The surface roughness Rz of the outermost layer was 8.3 μm, and the roughness variation was 0.1 μm.

Example 4T
In the production of the charging roll according to Example 1T, when the outermost layer forming material was prepared, a polyester resin (“Byron SS30” manufactured by Toyobo Co., Ltd.) was used instead of the urethane resin, the immonium. A charging roll according to Example 4 was produced in the same manner except that immonium dye B was used instead of system dye A. The hole on the outermost layer surface had an opening diameter of 120 μm and a depth of 4 μm. The outermost layer had a surface roughness Rz of 8.1 μm and a roughness variation of 0.2 μm.

(Example 5T)
In the preparation of the charging roll according to Example 1T, when the outermost layer forming material was prepared, the acrylic resin B was used instead of the urethane resin, and the phthalocyanine dye was used instead of 1 part by weight of the immonium dye A. (A charge roll according to Example 5T was produced in the same manner except that 10 parts by weight of “TX-EX-910B” manufactured by Nippon Shokubai Co., Ltd. was used. The diameter was 110 μm, the depth was 5 μm, and the surface roughness Rz of the outermost layer was 7.9 μm, and the roughness variation was 0.1 μm.

(Example 6T)
In preparing the charging roll according to Example 1T, when preparing the outermost layer forming material, except for using acrylic resin A instead of urethane resin, and using 0.5 parts by weight of immonium dye A. In the same manner, a charging roll according to Example 6T was produced. The hole on the outermost layer surface had an opening diameter of 110 μm and a depth of 4 μm. The surface roughness Rz of the outermost layer was 8.4 μm, and the roughness variation was 0.1 μm.

(Example 7T)
In the preparation of the charging roll according to Example 1T, when preparing the outermost layer forming material, the same except that the acrylic resin A was used instead of the urethane resin, and 30 parts by weight of immonium dye A was used. Thus, a charging roll according to Example 7T was produced. The hole on the outermost layer surface had an opening diameter of 110 μm and a depth of 7 μm. The surface roughness Rz of the outermost layer was 9.0 μm, and the roughness variation was 0.1 μm.

(Example 8T)
In the preparation of the charging roll according to Example 1T, when the outermost layer forming material was prepared, acrylic resin B was used instead of urethane resin, immonium dye A1 part by weight, and carbon black (Mitsubishi A charging roll according to Example 8T was produced in the same manner except that 10 parts by weight of “MA100” manufactured by Chemical Co., Ltd. was used in combination. The hole on the outermost layer surface had an opening diameter of 110 μm and a depth of 6 μm. The outermost layer had a surface roughness Rz of 8.8 μm and a roughness variation of 0.1 μm.
(Example 9T)

  100 parts by weight of nitrile rubber (NBR) (manufactured by Nippon Zeon Co., Ltd., “Nipol DN401”), 0.5 parts by weight of stearic acid, 3 parts by weight of the ionic conductive agent, and 5 parts by weight of zinc oxide (ZnO) 1 part by weight of a sulfenamide vulcanization accelerator (Ouchi Shinsei Chemical Co., Ltd., “Noxeller CZ-G”) and a dicarbamate vulcanization accelerator (Ouchi Shinsei Chemical Co., Ltd.) , “Noxeller BZ-P”) and 1 part by weight of powdered sulfur were kneaded with a kneader to prepare a conductive elastic layer forming material <T2> as an inner layer.

  In the preparation of the conductive elastic layer forming material <T1>, epichlorohydrin rubber (ECO) (manufactured by Daiso Corporation, “Epichromer CG102”) is changed to epichlorohydrin rubber (ECO) (manufactured by Daiso Corporation). In place of “Epichromer CG”), a rubber is prepared in the same manner, and 100 g of the rubber is dissolved in a mixed solvent of 300 g of MEK and 150 g of toluene, thereby preparing a conductive elastic layer forming material <T3> as an inner layer. did.

  Next, in the production of the charging roll according to Example 1T, the conductive elastic layer forming material <T2> is used instead of the conductive elastic layer forming material <T1>, and the conductive shaft is electrically conductive on the outer periphery of the conductive shaft. After forming a conductive elastic layer (functioning as a base layer), a conductive elastic layer forming material <T3> is applied to the outer periphery of this conductive elastic layer (80 μm) to obtain another conductive elastic layer. Layer (functioning as a resistance adjusting layer), the point of producing a roll body having two conductive elastic layers, when preparing the outermost layer forming material provided on the outer periphery of this roll body, instead of urethane resin A charging roll according to Example 9T was produced in the same manner except that the acrylic resin B was used. The hole on the outermost layer surface had an opening diameter of 120 μm and a depth of 4 μm. The outermost layer had a surface roughness Rz of 8.2 μm and a roughness variation of 0.1 μm.

(Comparative Example 1T)
Epichlorohydrin rubber (ECO) (Daiso Co., Ltd., “Epichromer CG102”) 80% by weight, NBR (Nippon ZEON Co., Ltd., “Nipol DN101”) 10% by weight, Liquid NBR (Nippon ZEON Co., Ltd.) ("Nipol 1312"), 10% by weight, and 1.5 parts by weight of sulfur, 1.5 parts by weight of tetramethylthiuram disulfide, 1 part by weight of stearic acid, 5 parts by weight of zinc oxide with respect to 100 parts by weight of this rubber component Part, 3 parts by weight of carbon black, 20 parts by weight of calcium carbonate, and 1 part by weight of anti-aging agent were added to prepare a rubber composition.

  Next, the rubber composition was poured into a cylindrical mold in which the conductive shaft was set coaxially, heated at 170 ° C. for 30 minutes, cooled and demolded. Thereby, a roll body having one conductive elastic layer (thickness 4 mm, length 240 mm) on the outer periphery of the conductive shaft was produced.

  Next, the surface of the obtained roll body was polished with an abrasive, and the surface of the grindstone was changed and polished until the 10-point average roughness described in JIS B0601 was 10 μm.

  Next, 80% by weight of an aqueous solution (20% solid content) in which a polyurethane resin (Daiichi Kogyo Seiyaku Co., Ltd., “Superflex 126”) is dispersed in water and 20% by weight of tin oxide are mixed in a ball mill. A coating solution was prepared.

  Next, the polished roll body was immersed in the coating solution, dried, and then heat treated at 150 ° C. for 10 minutes. Thereby, the charging roll which concerns on the comparative example 1T which has the film layer (30 micrometers) formed with the said coating solution on the surface of the said roll body was produced.

  The surface roughness Rz of the coating layer of the charging roll according to Comparative Example 1T was 8.4 μm, and the roughness variation was 1.6 μm.

2. Evaluation of each charging roll The following evaluation was performed for each charging roll produced in order to examine the difference in performance depending on the roughened state of the roll surface.

2.1 Roll surface hardness First, as reference data, the surface hardness of each charging roll was measured with an MD-1 hardness meter (manufactured by Kobunshi Keiki Co., Ltd., “Micro rubber hardness meter MD-1 type”) (N = 3)

2.2 Image Evaluation after Durability Test The following durability tests were performed on each charging roll, and the subsequent image evaluation was performed. That is, each charging roll was incorporated in a black cartridge of a commercially available color laser printer (manufactured by Canon Inc., “Laser Shot LBP-2510”).

  Next, with this color laser printer, 5000 half-tone images (A4 size) were printed in a black monochrome mode and in an environment of 15 ° C. × 10% RH, and the imaged images after endurance were visually confirmed. .

  As a result, both black spots and non-uniformity in density, and those in which density non-uniformity slightly occurred were accepted (in Table 2 described later, the former is indicated by a double circle and the latter is indicated by a circle). On the other hand, those that clearly showed both black spots and density unevenness were judged as rejected (indicated by cross marks in Table 2 described later).

2.3 Adhesiveness of external additive after durability test After the durability test of 2.2 above, the appearance of the charging roll was confirmed. That is, when such an endurance test is performed, a phenomenon occurs in which an external additive such as silica removed from the toner adheres to the roll surface.

  Here, after the endurance test of 2.2 above, there is almost no white powder on the roll surface, or there is a part where the white powder is slightly on the roll surface, or the entire roll surface is light. And white powder on top of each other were regarded as acceptable (in Table 2 to be described later, the former two are indicated by double circles and the latter are indicated by circles). On the other hand, after the durability evaluation, white powder adhered to the entire surface of the roll, and those that appeared white and exceeded gray were rejected (indicated by cross marks in Table 2 described later).

  Table 2 summarizes the composition and evaluation results of the outermost layer forming material of each charging roll.

  According to Table 2, the following can be understood. That is, the charging roll according to Comparative Example 1T had a bad image evaluation result after the durability test. This is because the roll surface has a large variation in roughness, resulting in non-uniform contact with the photosensitive drum, an unstable discharge state, and uneven charging, resulting in black spots and uneven density. It is presumed that this was due to the occurrence. Further, the charging roll according to Comparative Example 1T was liable to cause uneven adhesion of the external additive.

  On the other hand, all the evaluation results of the charging rolls according to Examples 1T to 9T were acceptable. As can be seen from the fact that the roughness variation of the outermost layer surface is small, a large number of holes are mainly formed by using a light-absorbing dye and laser processing technology, thereby uniformly roughening the outermost layer surface. It is presumed that this is because According to the charging rolls according to Examples 1T to 9T, it was confirmed that, compared to the conventional case, uneven charging and non-uniform adhesion of external additives are less likely to occur, and a good image can be obtained.

  Although the embodiments and examples of the present invention have been described above, the present invention is not limited to the above-described embodiments and examples, and various modifications can be made without departing from the spirit of the present invention.

Claims (5)

Provided on the outermost periphery of the roll with an outermost layer containing an organic polymer containing at least a light-absorbing dye,
An electroconductive roll for electrophotographic equipment, comprising a plurality of holes formed on the surface of the outermost layer by irradiation with a laser beam containing a wavelength absorbed by the light-absorbing dye . 2. The electroconductive roll for electrophotographic equipment according to claim 1, wherein the light absorbing dye has an effective absorption wavelength in a near infrared region having a wavelength of 500 to 1200 nm. The said light absorption pigment | dye contains at least 1 sort (s) or 2 or more types selected from a phthalocyanine pigment | dye, an immonium pigment | dye, an aminium pigment | dye, a naphthalocyanine pigment | dye, and a dioxazine pigment | dye. The electroconductive roll for electrophotographic equipment as described in 2. The electroconductive roll for electrophotographic equipment according to any one of claims 1 to 3, wherein the roll is a developing roll or a charging roll. A first step of forming an outermost layer containing an organic polymer containing at least a light-absorbing dye on the outermost periphery of the roll;
A second step of irradiating the surface of the outermost layer with laser light containing a wavelength absorbed by the light-absorbing dye, and forming a large number of holes;
The manufacturing method of the electroconductive roll for electrophotographic equipment characterized by including.