JP4952019B2 - Developer carrying member, method for producing the same, and developing device using the developer carrying member - Google Patents

Description

  The present invention relates to a developer carrier, a method for producing the same, and a developing device using the developer carrier, and in particular, a developer carrier and a developing device used in an image forming apparatus such as a printer, a copying machine, a facsimile machine, and a multifunction machine. And so on.

  In printers and copiers using electrophotographic technology, an electrostatic latent image is formed by an exposure device on a photosensitive member charged by a charging device, and a developer supplied from the developing device to the electrostatic latent image is supplied. The latent image is developed by electrostatic adsorption. In the developing apparatus, the developer is generally supplied using a cylindrical developer carrier, and an amount of developer corresponding to the charged potential of the photosensitive member is electrostatically charged during the development. There is a need to provide a latent image.

  However, when a developer having a small particle size or a high charging performance is used, the developer carrying member has a development capacity distribution due to the development history. As a result, an amount corresponding to the charged portion of the photosensitive member is generated. There is a case where the developer is not supplied, and a phenomenon that an unscheduled image appears in the development result, that is, a so-called development ghost occurs. For example, this is noticeable when a halftone image wider than the solid image is formed after the solid image is formed. The cause of the development ghost can be qualitatively explained as follows.

  FIG. 8 shows an outline of a developing device using a magnetic developer. In the developing device, a cylindrical developer carrier 120 having a magnet member 125 installed therein and rotating, is pressed against a housing 110 containing a magnetic developer 109, and an outer peripheral surface of the developer carrier 120. At least a layer forming blade 140 made of an elastic body or the like is provided.

  In the developing operation by the developing device, the magnetic developer 109 in the housing 110 is attracted to the developer carrier 120 by the magnetic force of the magnet member 125 and then conveyed by the rotating developer carrier 120 to be layered blade 140. By passing through, it will be in the state which consists of predetermined layer thickness. The magnetic developer 109 is charged by friction between the developers or friction with the layer forming blade 130. Subsequently, when the charged magnetic developer is transported to the development area facing the latent image carrier 200 such as a photoreceptor by the rotation of the developer carrier 120, the latent developer is transferred from the developer carrier 120 in the development area. The electrostatic latent image on the image carrier 200 is transferred to the electrostatic latent image by the action of a developing bias and is electrostatically attached, whereby the electrostatic latent image is developed and visualized. During this development, only the developer located in the portion corresponding to the electrostatic latent image among the developer on the developer carrier 120 is consumed. Further, a portion of the developer carrying member 120 where the developer is consumed is charged when a new developer is supplied in the housing 110 and passes through the layer forming blade 140.

  In such a developing operation, the developer newly supplied to the portion of the developer carrying member where the developer has been consumed in the developing process is subjected to frictional charging by the layer forming blade for the first time or a small number of times. On the other hand, the developer in the portion of the developer carrying member that has not been consumed is repeatedly subjected to frictional charging by the layer forming blade. As a result, the charge amount of the developer on the developer carrying member has a distribution according to the development history. In particular, when the charge amount is increased, the Coulomb interaction between the developer and the electrostatic latent image is increased, but at the same time, the attractive force due to the mirror image force is also increased between the developer and the developer carrier. The amount of developer transferred to the electrostatic latent image, that is, the developing ability, is determined by the magnitude relationship between these forces.

  For this reason, in actual development, there are cases where the developing force of the portion of the developer carrying member to which the developer has been newly supplied becomes higher and lower than that of the other portions, and an image is formed accordingly. An image (development ghost) different from the electrostatic latent image appears in the obtained image. As development ghosts that appear due to these factors, there are mainly types of ghosts (positive ghosts) in which an image that is not in the electrostatic latent image (a previously developed image) appears in the development result, and an electrostatic latent image. However, there is a type of ghost (negative ghost) that appears when a part of the latent image is not developed.

  Thus, since the development ghost is related to the charging performance of the developer, a developer having a small particle diameter which is advantageous for obtaining a high-quality image or a developer having improved charging performance was used. Sometimes it tends to occur prominently.

  In contrast, as a technique for dealing with development ghosts, for example, a resin layer made of a phenol resin containing carbon on the surface of a developer carrying member and provided with conductivity and surface lubricity is provided. A method for suppressing the development ghost is known (for example, Patent Document 1). In addition, a method is known in which the development ghost is suppressed by providing a film made of molybdenum on the surface of the developer carrier (for example, Patent Document 1).

  However, in the former method in which the resin layer is provided, since the resin layer is easily worn, the surface state of the developer carrying member changes as the developing operation is repeated, so that the period during which the development ghost can be suppressed is shortened. There was a problem. In addition, the latter method of providing the molybdenum film has a problem that when a developer for low-temperature fixing developed in recent years is used, the density of the obtained image is lowered because the chargeability of molybdenum is low. It was.

  Therefore, the applicant of the present invention, as a means for solving such a problem, a developer carrying member having a metal surface layer that expresses a specific specular gloss on a roughened cylindrical substrate, and the like. We have made proposals for developing devices and the like (patent application: unpublished at the time of this application).

  For example, as shown in FIG. 9, the developer carrying member 120 is subjected to a blasting treatment with a spherical abrasive (such as FGB # 60 or # 40) as a roughening treatment on an aluminum base 121, and an etching treatment or the like. After that, a metal surface layer 122 having a specific specular gloss was formed by plating with an electrolyte containing a brightener.

And in such a developer carrier, as shown in the same figure, if the metal surface layer (122a) is simply formed on the roughened substrate 121 having the macro unevenness R, the macro unevenness R is obtained. Although the micro unevenness r exists on the uneven surface in a substantially following state, the micro unevenness r is flattened and formed macroscopically by forming the metal surface layer 122b that contains the brightener to adjust the specular gloss. The unevenness R also has a smoother surface than the unevenness of the substrate 121. As a result, while ensuring the developer transportability of the developer carrier, the developer is reduced by reducing the fine roughness of the surface of the carrier and weakening the force of the developer adhering to the surface. It is possible to prevent remaining on the carrying surface (particularly micro uneven portions) and to suppress the development ghost due to the remaining of the developer over a long period of time.
JP 2000-231257 A JP-A-7-281517 JP-A-3-36562 JP-A-3-36563

  However, the developing apparatus using the proposed developer carrier also has the following problems.

  That is, when a developer carrier (including a developing device) is in an initial stage, particularly in a low-temperature and low-humidity environment, for example, a halftone image is developed after a belt-shaped image along the process direction is continuously developed. Is developed, a portion of the halftone image that is not developed to correspond to the previous band-like image may be generated as a negative ghost that deviates from the practically acceptable level (FIGS. 10 and 10). 11). FIG. 10 shows the occurrence situation in the case of G ghost (ghost phenomenon in which the history of the previous developed image appears as shading unevenness in the next developed image at the pitch of one round of the roll-shaped developer carrier). . FIG. 11 shows an HT ladder ghost (in a halftone image developed after continuous development of a strip-like image that is long in the image forming process direction, the portion corresponding to the strip-like image is darker than the other portions or The occurrence situation in the case of a positive or negative ghost phenomenon appearing as a lightly developed shading unevenness is shown. Such negative ghosts do not occur when the number of image forming (developing) sheets exceeds 100 to 500, exceeding an acceptable level of ± 0.25.

  According to the studies by the present inventors, in the developing device using the above-described proposed developer carrier, the developer carrier is in an initial stage particularly in a low temperature and low humidity environment. It has been confirmed that a phenomenon occurs in which the developer is undulated at a pitch of about 1 mm on the surface and is excessively conveyed (undulated conveyance). The developer carrying amount by the developer carrying member is normally in a proportional relation with the developer charging amount as illustrated in FIG. 12, but excessively when this wave-like carrying occurs. The result will rise. A result portion existing in a range surrounded by a dotted line in the figure shows a case where the wavy conveyance occurs. In the figure, the type of the metal surface layer for each result within the range is shown in parentheses. As a result, the amount of developer that can be developed increases and the development amount also increases, so that the development density of the subsequent image portion corresponding to the portion other than the preceding image (non-image portion) becomes high, It is assumed that the development density of the subsequent image portion corresponding to the preceding image portion becomes low, and this causes a negative ghost.

  Note that the occurrence of the wavy conveyance is assumed to have occurred for the following reason. First, the amount of charge tends to increase in a low-humidity developer environment, and there are many small particle sizes when fresh at the initial stage, so they are not consumed on the developer carrier in the development process. If it remains, the developer in a highly charged state is concentrated and strongly adheres electrostatically. On the other hand, since the surface of the developer carrying member is a smooth uneven surface, the developer is easily slipped on the developer carrying member. As a result, on the developer carrying member, an element that secures the transportability of the developer and an element that impedes the transportability work simultaneously. As a result, the transport of the developer is placed in an unstable state, and particularly when the developer (layer) passes through the layer forming blade, it slips and stays when it passes between the developer carrier. It is considered that the time is repeated and the developer is transported in a wavy layer state on the developer carrier due to this.

  In addition, the inventors of the present invention have been researching measures to prevent the above-described negative ghost from being struck so that irregular particles having sharp angles collide with each other to have sharp protrusions with a fine pitch. The surface of the projecting protrusion is formed so as to have a wavy uneven portion with a large pitch by receiving a collision with a regular particle having a smooth surface having an average particle size larger than the average particle size of the irregular particle. Thus, it has been found that there has been proposed a developing device using a developer bearing member having a surface in which the protrusion surface is blunted in the concave portion rather than in the convex portion (for example, Patent Documents 3 and 4).

  However, in such a developing device, the irregularity (sharpness) and minute irregularities formed by the collision of irregular particles are present on the surface of the developer carrying member, so that the developer is buried in the concave portions. As a result, the adhesion of the developer is promoted, and as a result, there is a problem that a development ghost (especially a positive ghost) easily occurs due to the development history.

  The present invention has been made in view of the various problems as described above. In addition to being able to suppress the occurrence of positive ghosts caused by development history, the present invention is particularly effective in a low-temperature and low-humidity environment. In addition to providing a developer carrier capable of suppressing the occurrence of negative ghosts at the stage and a developing device using the same, a method for producing such an excellent developer carrier is also provided. .

  The developer carrier of the present invention has a structure having a metal surface layer having a Gs (60 °) of 60 ° specular glossiness in the range of 10 or more and 40 or less on the rough surface of the roughened substrate. A developer carrying member for carrying and transporting the developer, wherein the roughened substrate is formed on a fine rough surface formed by colliding small spherical particles with respect to the small spherical particles. The substrate is characterized in that it is a substrate in a surface state interspersed with concave portions formed by colliding large spherical particles.

  The fine rough surface of the developer carrying member is a rough surface formed by the small-diameter spherical particles having a volume average particle diameter corresponding to a value of 5 to 20 times the volume average particle diameter of the developer. Is preferred.

  Further, the concave portion in the developer carrier is a rough surface formed by the small-diameter spherical particles having a volume average particle diameter corresponding to a value of 30 times or more the volume average particle diameter of the developer. preferable.

  Furthermore, the recesses in the developer carrier of any one of the configurations described above are recesses formed so that the fine rough surface portions remain scattered at an occupation ratio of 10 to 30%. Is preferred.

  The developing device of the present invention is characterized in that any one of the developer carriers having the above-described configurations is used as a developer carrier that carries and conveys the developer.

  Furthermore, the method for producing the developer carrying member of the present invention is the above-described method for producing the developer carrying member of the present invention, in which a fine rough surface is formed by colliding small spherical particles with the surface of the substrate. Later, a roughening step of the base material formed so as to be interspersed with concave portions by colliding spherical particles having a larger diameter than the spherical particles having a smaller diameter with the fine rough surface, and a rough surface in the roughening step. The metal surface layer in which the Gs (60 °) of the 60 ° specular glossiness comprised of the metal is in the range of 10 or more and 40 or less is obtained by subjecting the formed base material to electrolytic treatment with an electrolytic solution containing a metal. And a surface layer forming step of forming on the surface of the substrate.

  In the production method, the small-diameter spherical particles are preferably spherical particles having a volume average particle diameter corresponding to a value 5 to 20 times the volume average particle diameter of the developer.

  Further, in any one of the above-described production methods, the large-diameter spherical particles are spherical particles having a volume average particle diameter corresponding to a value of 30 times or more the volume average particle diameter of the developer. Preferably there is.

  According to the present invention, it is possible to suppress the generation of positive ghosts due to the development history, and also to carry the developer that can suppress the generation of negative ghosts in a low temperature and low humidity environment and at the initial stage. The body can be obtained. In addition, this makes it possible for a developing device using such a developer carrier to perform development with good image quality in which generation of both positive ghosts and negative ghosts is suppressed regardless of differences in use environment and use time. Become.

[Developer carrier]
As shown in FIGS. 1 and 2, the developer carrier 1 of the present invention has a Gs (60 °) of 60 ° specular glossiness of 10 or more and 40 on the rough surface of the base material 2 whose surface is roughened. A developer carrier having a structure having a metal surface layer 3 in the following range, which carries and conveys a developer, and the roughened substrate 2 is as shown in FIGS. In addition, the substrate in a surface state in which the fine rough surface 4 formed by colliding with the small-diameter spherical particles is dotted with the concave portions 5 formed by colliding the spherical particles larger than the small-diameter spherical particles. is there.

  As shown in FIG. 3, the base material 2 has relatively small spherical recesses formed between the relatively large spherical recesses 5 (ridges) present so that the surface is scattered. It is in a state where the fine rough surface 4 exists (rough surface 2a), the concave portion 5 exists as a spherical trough having a large diameter, and the trough has a plurality of fine rough surfaces 4 and small spherical concave portions. The surface is roughened to exist as a ridge portion. Then, the developer carrier 1 forms the metal surface layer 3 on the rough surface 2a of the base material 2 roughened in this way, thereby forming a fine rough surface of the base material 2 as shown in FIG. 4 and the recess 5 are both flattened to form a rough surface 2b that is smoother than the rough surface 2a of the substrate 2 so that the Gs (60 °) of the 60-degree specular gloss falls within a specific range. Configured. The illustrated metal surface layer 3 has a two-layer structure (first metal layer 3a, second metal layer 3b), but may have a one-layer structure or three or more layers.

  Since the developer carrier 1 is in such a surface state, it is difficult for the developer to be captured and adhered to the smooth and large concave portion 5, while the fine particle having the smooth and small concave portion. Although the developer is not buried in the rough surface 4 and remains, stable layer formation and conveyance of the developer are ensured. As a result, the developer is prevented from adhering as a whole, and stable developer layer formation and transportation are ensured. Therefore, the developer can be easily replaced regardless of the use environment and the use time. In this way, stable charging and conveyance are performed, thereby making it possible to suppress the occurrence of negative ghosts and positive ghosts.

  Examples of the base material 2 include aluminum and its alloys, stainless steel, etc., but aluminum or its alloys are preferable from the viewpoint of roughening the surface of the base material. Moreover, although the base material 2 of a cylindrical roll form is used normally, other forms, such as a belt form, may be sufficient as it.

  As shown in FIG. 3, the roughening of the base material 2 is a fine structure formed by colliding small-diameter spherical particles with the surface of the base material 2 before the roughening (surface on the side carrying the developer). A surface state in which the rough surface 4 and the concave portions 5 formed so as to be scattered in the rough surface 4 by colliding the fine rough surface 4 with spherical particles having a larger diameter than the small-sized spherical particles coexist. To do. Since the fine rough surface 4 and the recess 5 are both formed by colliding spherical particles, a blasting method in which spherical particles are sprayed dry on the surface of the substrate is usually applied. As long as the fine rough surface 3 and the concave portion 4 can be formed by colliding with each other, another method may be used.

  As shown in FIG. 4, the fine rough surface 4 has a spherical particle 7 having a small diameter with respect to the surface of the substrate 2 before roughening (the surface on which the developer is carried), preferably a volume average of the developer. It is a rough surface formed by colliding small-diameter spherical particles 7 having a volume average particle diameter corresponding to a value 5 to 20 times the particle diameter. When the small spherical particles 7 have a particle size smaller than 5 times the particle size of the developer, the developer can easily enter the concave portions of the rough surface formed by the particles 7. On the other hand, when the particle diameter is more than 20 times, there is a problem that wave-like conveyance occurs. The fine rough surface 4 is a rough surface having an arithmetic average surface roughness (Ra) in the range of 0.7 μm to 0.9 μm. When the arithmetic average surface roughness is less than 0.7 μm, the developer is likely to enter the rough surface recesses as in the case of using the spherical particles 7 having a small diameter as described above, as in the case of using the particles having a too small diameter. On the other hand, there is a problem that the adhesion is increased. On the other hand, if it is larger than 0.9 μm, there is also a problem that a wave-like conveyance occurs in the same manner, which is not preferable. For this reason, the collision conditions (pressure, collision treatment time, etc.) of the small-diameter spherical particles when forming the fine rough surface 4 are appropriately selected from the viewpoint of keeping the arithmetic average surface roughness within a preferable range. .

  The arithmetic average surface roughness Ra is measured according to JIS B0601 (2001) using a surface roughness measuring instrument (manufactured by Tokyo Seimitsu Co., Ltd .: Surfcom 590A-3DF). Specifically, under the measurement conditions of pickup E-DT-S01A, measurement length 4.0 mm, stylus tip 2 μmR, measurement speed 0.3 mm / s, cutoff value 0.8 mm, cutoff type 2CR (phase compensation) The measurement is made by measuring a total of nine locations in the rotational direction × 3 locations in the axial direction, and calculating the average value at that time. The arithmetic average surface roughness Ra described later is also based on the same measuring method.

  As shown in FIG. 4, the concave portion 5 has a spherical particle 8 having a larger diameter than the small spherical particle 7, preferably a developer, with respect to the rough surface 4 side of the substrate 2 on which the fine rough surface 4 is formed. It is a rough surface formed by colliding the said small diameter spherical particle 8 which consists of a volume average particle diameter corresponding to the value of 30 times or more of this volume average particle diameter. When the large spherical particles 8 have a particle size smaller than 30 times that of the developer, there is a problem that positive ghost is likely to occur.

  The recesses 5 are preferably formed such that the portions of the fine rough surface 4 are scattered and remain at an occupation ratio of 10 to 30%. In the case of the concave portion in which the occupation ratio of the portion of the fine rough surface 4 is less than 10%, there is a problem that wavy conveyance occurs, and on the contrary, the occupation ratio becomes larger than 30%. In the case of such a recess, there is a problem that positive ghost is likely to occur. In order to form the concave portion 5 in such a state that the occupation ratio of the portion of the fine rough surface 3 is ensured, it is possible to cope by appropriately adjusting the collision conditions (collision processing time, etc.) of the large-diameter spherical particles. it can. For example, the collision processing time for the large diameter spherical particles may be set to be shorter than the collision processing time for the small diameter spherical particles. Whether or not the concave portions 5 are formed at a predetermined ratio is determined based on the rough surface profile obtained by a laser microscope (for example, VK-8510 manufactured by KEYENCE Inc.) in the rough surface. This can be confirmed by determining the area occupied by the portion corresponding to the recess 5.

  The metal surface layer 3 has a 60 ° specular gloss Gs (60 °) in the range of 10 to 40, preferably in the range of 13 to 35. If this Gs (60 °) is less than 10, a ghost may occur in the image. On the other hand, if it exceeds 40, the surface is flattened and the developer is not uniformly transported, resulting in uneven density in the image. May occur. The 60-degree specular gloss is a value measured by Method 3 in accordance with JIS Z8741 (1997). In order to achieve such a 60-degree specular gloss, the thickness and surface roughness of the surface layer 3 and the concentration of the brightener and the current concentration when forming the surface layer 3 are appropriately adjusted. be able to.

  As the metal constituting the metal surface layer 3, nickel, copper, zinc, tin, gold, palladium, rhodium, ruthenium and the like can be applied, but nickel, copper, zinc and tin are preferable. Such a metal is suitable for the purpose of suppressing ghosts, in order to reduce the chargeability of the surface of the developer carrier, but it was thought that forming a surface layer with low-chargeability molybdenum or the like was effective. In the developer carrier of the invention, since the effect of suppressing the generation of ghosts can be obtained by making the surface roughness smooth, zinc or tin or the like having higher chargeability than molybdenum is added to the surface layer. This is because it can be used as a forming material, which makes it possible to achieve both suppression of ghosting and securing of image density, which is advantageous.

  The metal surface layer 3 has a rough surface with an arithmetic average surface roughness Ra in the range of 1.8 μm to 2.3 μm, preferably 1.9 to 2.2 μm. The arithmetic average surface roughness at this time corresponds to the measurement of macro unevenness present at a portion corresponding to the recess 5 formed on the substrate 2 in particular. When the arithmetic average surface roughness Ra is smaller than 1.8 μm, there is a problem that a positive ghost is generated or an image density is lowered due to an insufficient amount of developer transport. On the other hand, when it is larger than 2.3 μm, there are problems such as uneven conveyance due to wave-like conveyance and negative ghosts.

  Furthermore, the metal surface layer 3 has a microscopic roughness (root mean square roughness) Rq of 0.02 to 0.04 μm, preferably 0.025 to 0.035 μm. This microscopic roughness Rq particularly corresponds to a measurement of micro unevenness present at a site corresponding to the fine rough surface 4 formed on the substrate 2. If the microscopic roughness Rq is less than 0.02 μm, there is a problem such as uneven conveyance due to wave-like conveyance. Conversely, if it is larger than 0.04 μm, positive ghost is generated. There is a problem. The microscopic roughness Rq is measured as follows. First, a profile of the sleeve surface (corresponding to a roughness measurement curve) is obtained at a magnification of 100 times with a laser microscope (manufactured by KEYENCE: VK-8500), and obtained based on the profile. Specifically, the measurement pitch of the surface roughness is set to 0.15 μm in the length direction, the resolution in the height direction is set to 0.01 μm, and height data of 1024 points are collected in the length direction to obtain The resulting waveform (corresponding to the roughness measurement curve) is Fourier transformed to cut the long frequency component larger than the toner particle size and remove the waviness component to obtain a micro surface profile, and then the root mean square of the micro surface profile Calculate as a value.

  In order to obtain such a 60-degree specular gloss, arithmetic average surface roughness Ra, and microscopic roughness Rq of the metal surface layer 3, it is preferable to add a brightener. The amount of the brightener added varies depending on the type of the metal and the brightener, and thus cannot be generally stated, and is appropriately adjusted so as to fall within the above glossiness, arithmetic average roughness, and microscopic roughness ranges. Although it does not specifically limit as a brightener, For example, for zinc, Duo zinc 100, zinc light 1600, zinc light S-3400, zinc light K-2500, zinc light K-7500, zinc NH, zinc A-100, zinc A-200, zinc ACK, zinc A (above, Okuno Pharmaceutical Co., Ltd.) etc. can be mentioned. For nickel, Super Naolite, Super Zener, Monolite, Top Serena, Top Lunar, Top Leona NL, Acuna B-30, Acuna B, Turbo Light (above, Okuno Pharmaceutical Co., Ltd.), # 810 , # 81, # 83, # 81-J (above, manufactured by Ebara Eugleite Co., Ltd.). Examples of copper include KOTAC1, KOTAC2 (above, manufactured by Daiwa Special Co., Ltd.), Elecopper 25MU, Elecopper 25A (above, manufactured by Okuno Pharmaceutical Co., Ltd.), and the like.

  The thickness of the metal surface layer 3 is preferably in the range of 0.3 μm or more and 30 μm or less. If this thickness is less than 0.3 μm, the ground layer may be exposed due to abrasion of the surface layer due to repeated running of the developer carrier, and the ghost suppression effect may not be maintained. Since the thickness is increased, variation in the in-plane roughness of the surface layer occurs, and image density unevenness occurs, which is not preferable, and is not preferable from the viewpoint of production cost. This thickness is an average value obtained by measuring a total of 36 film thicknesses of 4 locations in the rotation direction and 9 locations in the axial direction per developer carrier using a fluorescent X-ray film thickness meter (SII: SFT3000S). Is calculated as

  The metal surface layer 3 may be formed on the rough surface (2a) of the base material 2 by subjecting the roughened base material 2 to electrolytic treatment with an electrolyte containing a metal constituting the metal surface layer 3. preferable.

  When forming the metal surface layer 3, the 60-degree specular gloss and surface roughness of the surface layer can be controlled by adjusting the amount of the brightener to be added and the thickness of the surface layer. The film thickness of the metal surface layer can be adjusted by the temperature of the electrolytic treatment, the current density, the electrolytic treatment time, and the like. In this case, the more the brightener added to the metal surface layer is increased, and the greater the film thickness of the surface layer is, the greater the 60 degree specular gloss of the surface layer can be increased. The surface roughness can be reduced. Moreover, the film thickness of a surface layer can be enlarged, so that the temperature of electrolytic treatment is high, a current density is high, and the electrolytic treatment time is lengthened.

  Further, the developer carrier 1 of the present invention is not particularly limited as long as it has at least the substrate 2 and the metal surface layer 3, and other layers may be formed as necessary. . For example, an undercoat layer may be provided between the base material 2 and the metal surface layer 3 in order to improve adhesion or adjust the charge amount. As the undercoat layer, for example, a metal such as nickel, copper, chromium, or gold can be used, and nickel or copper can be used. The undercoat layer may be a single layer or two or more layers. The total thickness of the undercoat layer is preferably 0.3 or more and 5.0 μm or less. Such an undercoat layer is preferably formed by electrolytic plating or electroless plating, and particularly preferably by electroless plating.

[Development equipment]
The developing device of the present invention uses the developer carrier 1 of the present invention described above as a developer carrier that carries and conveys the developer. By using this developer carrier 1, it is possible to suppress the occurrence of positive ghosts due to development history, and also to suppress the occurrence of negative ghosts in the initial stage in a low temperature and low humidity environment. Become.

  The developer applicable to the present invention may be either a magnetic one-component developer or a two-component developer, but is particularly effective when a magnetic one-component developer is applied.

  FIG. 5 shows an example of a developing apparatus suitable for carrying out the present invention.

  In FIG. 5, the developing device 10 is disposed to face a latent image carrier 200 such as a photoconductor on which an electrostatic latent image is formed. The developing device 10 has a housing 11 that opens at a portion facing the latent image carrier 200 and accommodates the magnetic developer 9. A developing roll 12 is rotatably installed facing the opening of the housing 11. In addition, a layer forming member 14 is provided on the upper edge of the opening to bring the magnetic developer 9 supported on the roll 1 into a thin layer state by being pressed against the developing roll 1.

  The housing 11 has a developing chamber 11b in which the developing roll 1 exists, and a toner storage chamber 11c in which the developer 9 is stored behind the developing chamber 11b, with a partition wall portion 11a formed of a part of the housing as a boundary. It is divided into. The toner storage chamber 11c is provided with a rotary stirring member 15 for scraping out (supplying) the developer 9 stored therein to the developing chamber 11b side.

  The developing roll 12 includes a cylindrical developing sleeve (developer carrier) 1 and a magnet roll 13 installed in the internal space of the developing sleeve 1. The magnet roll 13 is for appropriately arranging the N pole and the S pole at predetermined positions to form a uniform magnetic field in the axial direction, and both ends of the roll are fixed to the housing 11. A developing bias (for example, an AC voltage superimposed on a DC voltage) is applied from a bias power supply 16 to the developing roll 12 (actually the developing sleeve 1).

  The layer forming member 14 is obtained by attaching an elastic body 14b made of rubber or the like to a support plate 14a made of stainless steel, copper, iron, synthetic resin or the like. The rotary stirring member 15 has, for example, a structure in which a flexible film is attached to a part of the rotating body.

  The developing device 10 operates as follows.

  First, when it is time to develop, the developing roll 12 (developing sleeve 1) and the rotary stirring member 15 start rotating, and a developing bias is applied to the developing roll 12 from the bias power supply device 16. As a result, the magnetic developer 9 in the housing 11 is agitated by the rotary agitating member 15 in the toner accommodating chamber 11c, and a part of the magnetic developer 9 is conveyed to the developing chamber 11b side and supplied to the developing roll 12.

  Subsequently, the magnetic developer 9 adheres to the surface of the developing sleeve 1 by the magnetic force of the magnet roll 13 in the developing chamber 11b, and then the layer thickness is regulated by the protruding amount and the contact pressure of the layer forming member 14, and Frictional charge. The developer 9 thus charged and layered is transported to the developing area facing the latent image carrier 200 by the rotation of the developing roll 12, and the latent image formed on the latent image carrier 200 in the developing area. It moves to the image portion and adheres electrostatically. Thereby, the electrostatic latent image is developed.

  In the development by the developing device 10, the surface of the developing sleeve 1 is subjected to a strong stress such that the developer 9 is pressed by the friction between the developing sleeve 1 of the developing roll 12 and the layer forming member 14 in pressure contact therewith. . However, since the developer carrying member of the present invention is used as the developing sleeve 1, the developer 9 is less likely to be embedded in the surface of the developing sleeve 1, and thus hardly remains on the surface. Further, since the surface of the developing sleeve 1 is in a smooth and rough state, the transport amount of the developer 9 is also stable. As a result, the occurrence of development ghosts (particularly positive ghosts) during normal times can be suppressed, and good development can be performed. Furthermore, since the surface of the developing sleeve 1 has a particularly fine rough surface portion (the portion of the metal surface layer 3 corresponding to the fine rough surface 4 of the base material 2), it is used in an environment of low temperature and low humidity and is used for the initial use. Even at this stage, since a predetermined amount of developer 9 is transported, development ghosts (particularly negatives) can be suppressed, and good development can be achieved even in such an environment and use stage. It can be carried out.

  Hereinafter, the present invention will be described more specifically with reference to examples.

<Production of developer carrier (developing sleeve)>
1. Substrate roughening process:
FGB # 400 (corresponding to a particle size of 44 to 53 μm) (a particle size of 44 to 53 μm) is formed on the peripheral surface of a cylindrical aluminum (A6063) tube formed by cutting after pultrusion as the base material 2. Blast treatment of the previous stage was performed using a two-manufactured product. The blasting process in the previous stage was performed by spraying a spherical abrasive onto the aluminum tube of the base material 2 rotated at a speed of 18 rpm with a blasting pressure of 1.9 Mpa and a blasting time of 90 seconds. The arithmetic average surface roughness Ra of the obtained aluminum tube was measured and found to be 0.8 μm.

  Subsequently, the aluminium pipe after the preceding blast treatment was subjected to the subsequent blast treatment using FGB # 60 (corresponding to a particle size of 250 to 350 μm) which is a large-diameter spherical abrasive (8). . This subsequent blasting process was performed by spraying a spherical abrasive onto the aluminum tube of the substrate 2 rotated at the same speed with a blasting pressure of 2.0 MPa, a blasting time of 30 seconds. When the surface of the obtained aluminum tube was observed with a laser microscope to obtain an uneven profile, it was confirmed that the fine rough surface (4) formed in the previous stage remained with an occupation ratio of about 20%.

2. Surface layer forming process:
The aluminum tube (base material 2) subjected to the roughening treatment was subjected to a double zincate treatment after being subjected to an etching treatment in order to improve the adhesion of plating. On the other hand, the processing liquid was prepared using the processing liquid of Ni-P (nickel-phosphorus) which consists of a main ingredient (Okuno Pharmaceutical Co., Ltd. product: Top Nicotron BL-M / BL-1). Then, the roughened aluminum tube was electrolessly treated with this Ni-P treatment solution, thereby forming a Ni-P plating layer (3a) having a thickness of 2.0 ± 0.5 μm.

  Subsequently, a treatment prepared by adding 4 ml / l of a brightener (Okuno Pharmaceutical Co., Ltd .: Zinc Client 1600) to a Zn cyanide bath built using a main agent (manufactured by Showa Chemical Co., Ltd .: Zn oxide reagent). A liquid was prepared. Then, using the treatment liquid containing the brightener, the aluminum tube subjected to the Ni-P plating is subjected to an electrolysis treatment to form a Zn (zinc) plating layer (3b) on the Ni-P plating layer. did. Incidentally, although the addition amount of the brightening agent varies depending on the kind of the metal or the brightening agent forming the surface layer, it is preferably adjusted as appropriate from the viewpoint that the microscopic roughness Rq falls within the required range.

  As a result, a developing sleeve (1) as a developer carrying member was obtained (No1). When the 60-degree specular gloss, arithmetic average surface roughness Ra, and microscopic roughness Rq of this developing sleeve were measured, Gs (60 °) was “20”, Ra was “2.0 μm”, and Rq was “0”. 0.03 μm ”. The developing sleeve has an outer diameter of about 16 mm. FIG. 7 shows the manufacturing conditions and characteristics measurement results of this developing sleeve.

<Developer conditions>
The developing device 10 uses the above-made one as the developing sleeve 1 of the developing roll 12, and the magnet roll 13 having a developing pole having a magnetic force of 900 gauss (× 10 ⁻⁴ T). . The developing roll 12 was applied with a developing bias biased with a DC voltage of −400 V and an alternating voltage composed of a rectangular wave having a frequency of 3.3 kHz and a peak-to-peak voltage V _pp of 1.8 kV as a developing bias. As the layer forming member 14, a metal support plate attached with an elastic body made of urethane resin (JIS A hardness 65, tensile strength 25 MPa, thickness 1.3 mm) is used, and the linear load becomes 60 g / cm. In this manner, it was brought into pressure contact with the developing roll 12 in a belly contact state.

  The developing device 10 is installed with a 250 μm gap with respect to the photosensitive drum as the latent image carrier 200 on which an organic photosensitive layer having a diameter of 30 mm is formed, and the developing sleeve 1 is rotated at the rotational speed of the photosensitive drum. It was rotated at a speed of 1.05 to 1.2 times (204 mm / sec). Further, the developer 9 having the following conditions was used.

<Preparation of developer>
Binder resin: Polyester resin: 50.0 parts by weight (Alcohol component: propylene oxide adduct of bisphenol A, acid component: terephthalic acid, melt index (MI): 6 g / 10 min, glass transition point (Tg): 58 ° C. )
Magnetic substance: magnetite ... 45.5 parts by weightNegative charge control agent ... 1.0 part by weight (Fe-containing azo dye, manufactured by Hodogaya Chemical Co., Ltd .: T77)
-Polypropylene wax: 3.5 parts by weight (manufactured by Sanyo Chemical Co., Ltd .: 660P)
External additive: silica fine particles having an average primary particle size of 12 nm (average primary particle size of 50 nm n anatase fine particles were treated with decylsilane / silicone oil)

  The materials having the above composition were mixed with a Henschel mixer, and then heat kneaded with an extruder having a set temperature of 140 ° C. The kneaded product was cooled and then coarsely and finely pulverized to obtain a pulverized product having a volume average particle diameter D50 of 5.8 μm. Further, the pulverized product was classified to obtain a toner classified product having D50 of 6.2 μm and 22% of particles of 4 μm or less. Then, with respect to 100 parts by weight of the obtained toner classified product, 1.2 parts by weight of dimethylcellulose oil-treated silica fine particles (carbon number 7.5% by weight) having a particle diameter of 12 nm and decyltrimethoxysilane 10% by weight. 0.6 parts by weight of titanium oxide fine particles having an average primary particle size of 50 nm that had been surface-treated with a Henschel mixer were externally added. Thereby, a magnetic one-component developer was obtained.

<Manufacturing other developer carrier>
In the production of the developer carrying member, various kinds of developer carrying were carried out in the same manner except that the polishing agent, blasting conditions, etc. in the roughening step of the aluminum tube as the base material were changed to the contents shown in FIG. The body was manufactured (Sample No. 0, 1, 2). Each physical property of each developer carrier thus obtained was measured in the same manner as described above. The result is shown in FIG.

<Evaluation test>
A test is carried out in which the developer carrier 10 is mounted (replaced) and the developer 10 containing the developer is accommodated and mounted as a developer of an image forming apparatus (Fuji Xerox Co., Ltd .: DocuPrint 340A). Using a modified machine, a test image was printed and the development ghost was examined.

Regarding the development ghost, the occurrence of ghost (especially negative ghost: NG) in the initial stage (first printing operation stage) in an environment of low temperature and low humidity (10 ° C., 15% RH) and normal temperature and normal humidity (22 ° C., 55 % RH), the occurrence of ghosts (especially positive ghosts: PG) in the time-lapsed stage (the stage where the number of printed sheets is 10,000) was examined. In the test, after printing one solid black image and three solid white images, a ghost chart image (a character image of “A” and a halftone image) as a test image shown in FIG. 6A is printed. Then, the print results were evaluated by the following criteria by visual inspection. The symbol L in FIG. 6 is the circumference of the developing sleeve. The results are shown in FIG.
(Triangle | delta): Although ghost generation | occurrence | production is a practically acceptable level.
X: A ghost is remarkably generated and is an unacceptable level.

  When a ghost occurs, the image density in the ghost occurrence area and the non-occurrence area in the print image is measured by a density measuring device (X-Rite: 404a), and the density difference at that time (non-occurrence area) Ghost grade “± 0.25”, when ± 0.1, “± 0.5”, when ± 0.2, and “± “± 1.5” when 1 and ± 0.3, “± 2” when ± 0.4, and “± 3” when exceeding ± 0.4. At this time, the allowable range of the ghost grade was “within ± 0.25”. The result of this ghost grade is shown in parentheses in FIG. Note that the ghost grade with a value of “+” corresponds to a case where a positive ghost has occurred, and a value with a sign of “−” corresponds to a case where a negative ghost has occurred.

  As is clear from the results of FIG. In the case of using a developing sleeve manufactured without performing the plast treatment before the surface roughening treatment of the 0 substrate, the development ghost after 10k (10000) sheets can be suppressed, but the environment is low temperature and low humidity. It can be seen that a development ghost (especially a negative ghost) occurs in the initial stage.

  10 and 11 show the sample numbers. The result of having investigated the generation | occurrence | production condition of the development ghost (G ghost and HT ladder ghost) at the time of using the image development sleeve of 0 is shown. The ghost grade is the same as that applied in the evaluation test. In addition, FIG. It is the result of investigating the relationship between the toner charge amount and the toner transport amount in the developing device using the zero developing sleeve. The result surrounded by the dotted line in the figure shows the transport amount when the corrugated transport occurs in the initial stage under the low temperature and low humidity environment as described above.

  And from the result of FIG. It can be seen that when the developing sleeves 1 and 2 are used, it is possible to suppress both development ghost generation at the stage after 10k sheets and development ghost generation at the initial stage at low humidity and low temperature. On the other hand, sample no. When the developing sleeve No. 2 was used, it was confirmed that a positive ghost was generated at an early stage or that a positive ghost was generated even with time.

  Therefore, in order to suppress both the development ghost generation at the stage after 10k sheets and the development ghost generation at the initial stage at low humidity and low temperature, it is sufficient to use a development sleeve that satisfies the following conditions. found.

It is a schematic explanatory drawing which shows one structural example of the developer carrier of the present invention. It is an expansion schematic sectional drawing which shows the part enclosed with the circle | round | yen S of FIG. FIG. 2 is an enlarged schematic cross-sectional view showing a roughened substrate in the developer carrying member of FIG. 1. FIG. 4 is a schematic cross-sectional explanatory view showing each step during the surface roughening treatment of the substrate of FIG. 3. It is a schematic explanatory drawing which shows the example of 1 structure of the image development apparatus of this invention. For explaining the occurrence of a development ghost, (A) is a ghost chart image, (B) is an explanatory plan view showing a case where a positive ghost is generated, and (C) is a plan view showing a case where a negative ghost is generated. 4 is a chart showing the configuration conditions, measurement results, and evaluation test results for each developer carrier. It is a schematic explanatory drawing which shows an example of the conventional developing device. It is a schematic sectional drawing which expands and shows a part of proposed developing agent carrier. FIG. 10 is a graph showing the results of examining the occurrence of G ghost when the developer carrying member of FIG. 9 is used. FIG. 10 is a graph showing the results of examining the occurrence of HT ladder ghost when the developer carrying member of FIG. 9 is used. FIG. 10 is a graph showing the results of a test examining the relationship between the toner charge amount and the toner transport amount when the developer carrying member of FIG. 9 is used.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Development sleeve (developer carrier), 2 ... Base material, 2a ... Rough surface, 3 ... Metal surface layer, 4 ... Fine rough surface, 5 ... Recessed part, 7 ... Small diameter spherical particle, 8 ... Large diameter spherical shape Particles, 9 ... Magnetic developer (developer), 10 ... Developing device.

Claims (5)

Conveying and carrying a developer, which has a structure having a metal surface layer having a Gs (60 °) of 60 ° specular glossiness in the range of 10 or more and 40 or less on the rough surface of the substrate whose surface is roughened A developer carrying member,
The roughened base material is interspersed with fine concaves formed by colliding small spherical particles with concave portions formed by colliding larger spherical particles than the small spherical particles. A developer carrying member which is a surface-state substrate. 2. The developer carrying member according to claim 1, wherein the concave portions are concave portions formed such that portions of the fine rough surface are scattered and remain at an occupation ratio of 10 to 30% . A developing device using the developer carrying member according to claim 1 or 2 as a developer carrying member carrying and transporting the developer . A method for producing a developer carrier according to claim 1,
After forming a fine rough surface by colliding small spherical particles with the surface of the substrate, the fine rough surface is scattered with concave portions by colliding larger spherical particles than the small spherical particles. A surface roughening step of the base material to be formed,
The base material roughened in the roughening step is subjected to electrolytic treatment with an electrolytic solution containing a metal, and the Gs (60 °) of 60 ° specular gloss composed of the metal is 10 or more and 40 or less. A surface layer forming step of forming a metal surface layer in a range on the surface of the substrate; and
A method for producing a developer carrying member, comprising: The condition for causing the large-diameter spherical particles to collide is set so as to satisfy the conditions for forming the concave portion so that the fine rough surface portions remain scattered at an occupation ratio of 10 to 30%. Item 5. The production method according to Item 4 .

Images