JP2010128348A - Developing roller, electrophotographic process cartridge, and electrophotographic image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a developing roller reducing a frictional force with other members in the initial stage of the image formation under high-temperature and high-humidity and suppressing image defects caused by the fixing of developer and particles. <P>SOLUTION: The developing roller includes a shaft core body and a resin layer provided on the circumference of the shaft core body and including a polyurethane resin. Porous resin particles are adhered to the surface of the resin layer, to be releasable from the surface of the resin layer. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a developing roller having porous resin particles attached thereto, an electrophotographic process cartridge and an electrophotographic image forming apparatus using the developing roller.

  As an image forming method of an electrophotographic image forming apparatus such as a copying machine or an optical printer, a developing method using a non-magnetic one-component developer (hereinafter sometimes referred to as toner) is known. Specifically, a rotatable photoreceptor is uniformly charged by a charging means such as a charging roller, and a laser beam is exposed to the uniformly charged photoreceptor surface to form an electrostatic latent image. Next, in the developing device, the toner in the developer container is uniformly applied onto the developing roller by the developer supply roller and the developer amount regulating member, and development with the toner is performed at the contact portion between the photosensitive member and the developing roller. . Thereafter, the toner image on the photosensitive member is transferred onto the recording material in the transfer portion, fixed by heat and pressure in the fixing portion, and the recording material on which image formation has been completed is discharged out of the electrophotographic image forming apparatus.

  In such an image forming method, examples of the developing device include those having the following configurations. A developing roller is provided so that the opening of the developer container for storing the toner is closed and a part thereof is exposed to the outside of the container, and the exposed part is opposed to the photosensitive member. In the developer container, there are provided a developer supply roller for supplying toner to the developing roller, and a developer amount regulating member for forming the toner on the developing roller in a thin film and making the toner on the developing roller a constant amount. A developing roller is generally used in which a resin layer having elasticity is formed around a metal core.

  The developing roller formed of such an elastic material has an increased surface tack property in a special environment such as high temperature and high humidity, and increases the driving torque of the developing roller due to an increase in frictional force with the developer amount regulating member. In some cases, the toner may adhere to the surface of the developing roller.

  In particular, in recent years, as a countermeasure for increasing the durability of the electrophotographic image forming apparatus, a softening of the surface hardness of the developing roller has been studied, but as a negative effect, a countermeasure for the above-mentioned toner fixation is particularly required. It has become to.

A conventionally known developing roller configuration includes a method of attaching fine particles to the surface of the developing roller (Patent Documents 1 to 4). However, these methods are effective in reducing driving torque, but are insufficient in fixing toner onto the surface of the developing roller due to increased tackiness under high temperature and high humidity. Further, countermeasures are insufficient for the problem that the fine particles themselves adhere to the surface of the developing roller.
JP-A-8-179619 JP-A-9-62086 JP-A-11-65266 JP 11-311890 A

  An object of the present invention is to develop a developing roller, an electrophotographic process cartridge, and an electrophotographic film that can reduce frictional force with other members even under high temperature and high humidity, and can suppress image defects due to adhesion of toner and particles. Another object is to provide an image forming apparatus.

  By attaching porous resin particles having specific properties to the surface of the developing roller, the present inventors reduce the frictional force with other members even under high temperature and high humidity, and fix toner and particles. It has been found that image defects due to can be suppressed. Based on this knowledge, the present invention has been completed.

  That is, the present invention relates to a developing roller having a shaft core body and a resin layer provided on the outer periphery of the shaft core body, wherein the resin layer contains a polyurethane resin, and porous resin particles are formed on the surface of the resin layer. Is attached to the surface in a detachable manner.

  The present invention also provides a developing roller that supplies toner to the surface of the latent image carrier to form a developer image, and a developer that forms a toner on the developing roller in a thin film so that the amount of toner on the developing roller is constant. An electrophotographic process cartridge that is detachably attached to an electrophotographic image forming apparatus having a quantity regulating member, wherein the developing roller is the developing roller.

  The present invention also provides a developing roller that supplies toner to the surface of the latent image carrier to form a toner image, and a developer amount that forms the toner on the developing roller in a thin film and makes the toner on the developing roller a constant amount. An electrophotographic image forming apparatus comprising a regulating member, wherein the developing roller is the developing roller.

  The developing roller of the present invention reduces the frictional force with other members under high temperature and high humidity, and suppresses image defects caused by the toner and porous resin particles adhering to the surface of the developing roller. it can. In addition, the electrophotographic process cartridge and the electrophotographic image forming apparatus of the present invention reduce the frictional force between the developing roller and other members under high temperature and high humidity, and develop toner and porous resin particle developing rollers. Good image formation can be performed by preventing sticking to the surface.

  The developing roller 1P to which the porous resin particles of the present invention are attached has a configuration as shown in FIG. 1 as an example, and includes a shaft core body 2 and a resin layer 4 provided around the shaft core body 2. Porous resin particles 5 are attached to the surface of the roller so as to be removable from the surface.

<Resin layer 4>
The resin layer 4 provided on the outer periphery of the shaft core body 2 contains a polyurethane resin. Examples of the polyurethane resin contained in the resin layer 4 include ether polyurethane, ester polyurethane, acrylic polyurethane, and carbonate polyurethane. Among these, a polyether polyurethane resin that easily imparts a negative charge to the toner by a frictional force with the toner is preferable.

  The polyether polyurethane resin can be obtained by a reaction between a known polyether polyol and an isocyanate compound. Examples of the polyether polyol include polyethylene glycol, polypropylene glycol, and polytetramethylene glycol. Further, these polyol components may be prepolymers that are chain-extended in advance with the following isocyanate as necessary. 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate (TDI), diphenylmethane diisocyanate (MDI), isophorone diisocyanate (IPDI).

  Although it does not specifically limit as an isocyanate compound made to react with these polyol components, For example, the following compounds can be used. Aliphatic polyisocyanates such as ethylene diisocyanate, aliphatic polyisocyanates such as 1,6-hexamethylene diisocyanate (HDI), isophorone diisocyanate (IPDI), cyclohexane 1,3-diisocyanate, cyclohexane 1,4-diisocyanate, 2,4 -Aromatic polyisocyanates such as tolylene diisocyanate, 2,6-tolylene diisocyanate (TDI), diphenylmethane diisocyanate (MDI), modified products and copolymers thereof, and block bodies thereof.

  If the surface roughness is required for the developing roller 1P to which the porous resin particles are adhered, fine particles for controlling the roughness may be added to the resin layer 4. The volume average particle diameter of the fine particles for roughness control is preferably 3 to 20 μm. The addition amount of the fine particles for roughness control added to the resin layer 4 is preferably 1 to 50 parts by mass with respect to 100 parts by mass of the resin solid content of the resin layer 4.

  As the fine particles for roughness control, fine particles of polyurethane resin, polyester resin, polyether resin, polyamide resin, acrylic resin, and polycarbonate resin can be used. These can be used alone or in combination of two or more.

  The resin layer 4 preferably contains a conductive agent. As the conductive agent, carbon black is preferable because the triboelectric chargeability to the toner and the adhesion on the surface of the resin layer 4 can be controlled to an optimum balance.

  Specific examples of the carbon black include the following. "Ketjen Black" (trade name, manufactured by Lion Corporation), conductive carbon black such as acetylene black; carbon black for rubber such as SAF, ISAF, HAF, FEF, GPF, SRF, FT, MT. In addition, carbon black for color ink and pyrolytic carbon black that have been subjected to oxidation treatment can be used. These can be used alone or in combination of two or more.

  The content of carbon black is preferably 10 to 30% by mass in the resin layer 4.

  In addition to the carbon black, usable conductive agents include the following. Natural or artificial graphite; metal powder such as copper, nickel, iron and aluminum; metal oxide powder such as titanium oxide, zinc oxide and tin oxide; conductive polymer such as polyaniline, polypyrrole and polyacetylene. These may be used alone or in combination of two or more as required.

  The resin layer 4 has other crosslinking agents, plasticizers, fillers, extenders, vulcanizing agents, vulcanization aids, crosslinking aids, antioxidants, anti-aging agents, processing aids as long as the functions are not impaired. An agent and a leveling agent can be contained.

  The thickness of the resin layer 4 is preferably in the range of 1 to 100 μm.

<Porous resin particles>
The porous resin particles 5 are attached to the surface of the resin layer 4 so as to be removable from the surface. Here, “removably adheres” means that the porous resin particles 5 are adhered to the surface by an adhesive tape (trade name “Scotch Mending Tape” (manufactured by Sumitomo 3M Co., Ltd.)). On the other hand, the case where it adheres to the extent that it cannot be peeled off from the surface due to the adhesive force of the above-mentioned adhesive tape is defined as “adherence” in the present invention.

  By adhering the porous resin particles 5 to the surface of the resin layer 4 so as to be removable from the surface, it is possible to effectively suppress toner sticking to the resin layer 4 at the initial stage of image formation under high temperature and high humidity. it can. The reason is not clear at present, but the porous resin particles 5 have a relatively small specific gravity and a relatively small contact area with the surface of the resin layer 4, so that the surface of the resin layer 4 is likely to roll. Guessed.

  The number average particle diameter of the porous resin particles 5 is preferably 5 to 50 μm, particularly preferably 10 to 30 μm. When the number average particle size is within the above numerical range, it is possible to suppress the porous resin particles 5 from being fixed to the surface of the resin layer 4. Further, since the porous resin particles 5 can be adhered closely, it is possible to suppress the resin layer 4 and the toner from coming into direct contact with each other. As a result, the toner can be effectively prevented from sticking to the surface of the resin layer 4.

Moreover, it is preferable that the specific surface area of the porous resin particle 5 is 2-100 m < ² > / g, especially 10-70 m < ² > / g. By setting the specific surface area within the above numerical range, it is possible to prevent the porous resin particles 5 from having sufficient water absorption and increasing the tackiness of the surface of the developing roller. As a result, it is possible to suppress adhesion of the toner or the like to the surface of the resin layer 4. Further, the damage of the porous resin particles 5 due to the embrittlement of the porous resin particles 5 can be effectively suppressed.

  The compressive strength of the porous resin particles 5 is preferably 1.0 to 5.0 MPa or less, particularly 2.0 to 4.0 MPa. By setting the compressive strength within the above numerical range, it is possible to suppress the porous resin particles 5 from being excessively soft and sticking to the surface of the resin layer 4. Moreover, excessive stress is not applied to the resin layer 4 during driving, and the resin layer 4 can be prevented from being damaged.

  The porous resin particles 5 can have various shapes such as a spherical shape and a lump shape, but are preferably spherical in order to prevent the porous resin particles 5 from being fixed. Here, the spherical shape refers to particles having an arithmetic average circularity of 0.96 to 1.00 measured by a measurement method described later. The arithmetic average circularity is an index indicating the degree of unevenness of the particle, and is 1.00 when the particle is a perfect sphere. The more complex the surface shape, the smaller the arithmetic average circularity.

  As the porous resin particles 5 of the present invention, various materials and particles having physical properties can be generally used. Examples of such porous resin particles 5 include porous acrylic resin particles and porous polyamide resin particles. It is done. Since these particles 5 also have water absorbency, moisture is absorbed on the surface of the surface layer 4 under high temperature and high humidity conditions, the resin layer 4 absorbs moisture, and the tackiness of the surface of the resin layer 4 is increased. It is speculated that this can be effectively suppressed.

  Porous acrylic resin particles on the market include “Matsumoto Microsphere M-600” (trade name) manufactured by Matsumoto Yushi Co., Ltd., and “Tech Polymer ARP-8” manufactured by Sekisui Plastics Co., Ltd. (product) Name). Examples of the commercially available porous polyamide resin particles include “POMP” (trade name) manufactured by Ube Industries, Ltd.

  As an example of a method for producing porous acrylic resin particles, a mixed liquid of water and an organic solvent containing a polymerizable acrylic monomer such as (meth) acrylic acid, (meth) acrylate, and (meth) acrylate and a crosslinking agent Examples thereof include a method obtained by suspension polymerization.

  In addition, as an example of a method for producing porous polyamide resin particles, there is a method of obtaining porous polyamide resin particles by preparing a mixed liquid of a polyamide resin and its good solvent, poor solvent, and water, and then allowing it to stand still. It is done.

  The porous resin particle 5 of the present invention preferably has appropriate adhesion on the surface of the resin layer 4. For example, it is preferable that the electrophotographic image is not affected as much as possible even when fixed to the developing roller. As such porous resin particles, those having a charged series close to that of the polyurethane resin are preferable, and specific examples include porous acrylic resin particles.

The porous resin particles 5 have an adhesion density to the surface of the resin layer 4 of 0.10 to 1.00 mg / cm ² , more preferably 0.40 to 0.60 mg / cm ² . By setting the adhesion density in such a numerical range, toner adhesion prevention and porous resin particle 5 adhesion prevention are more effectively performed.

  Further, as described above, the developing roller 1P to which the porous resin particles 5 of the present invention are attached has the resin layer 4 around the shaft core body 2. As shown in FIG. One or more elastic layers 3 can be provided between the core body 2 and the resin layer 4.

  Such an elastic layer 3 is preferably formed of a rubber material, and specific examples include the following. Ethylene-propylene-diene copolymer rubber (EPDM), acrylonitrile-butadiene rubber (NBR), chloroprene rubber (CR), natural rubber (NR), isoprene rubber (IR), styrene-butadiene rubber (SBR), fluorine rubber, silicone Rubber, epichlorohydrin rubber, NBR hydride, urethane rubber. These can be used alone or in combination of two or more. Of these, silicone rubber is preferable because of its flexibility and low compression set. Examples of the silicone rubber include polydimethylsiloxane, polymethyltrifluoropropylsiloxane, polymethylvinylsiloxane, polyphenylvinylsiloxane, and copolymers of these polysiloxanes.

  The elastic layer 3 preferably contains a conductive agent. As the conductive agent, either an ionic conductive agent or an electronic conductive agent may be used. Specifically, carbon-based materials such as carbon black and graphite; metal powders such as copper, nickel, iron and aluminum; metal oxide powders such as titanium oxide, zinc oxide and tin oxide; conductive materials such as polyaniline, polypyrrole and polyacetylene. Can be mentioned. These can be used alone or in combination of two or more. These conductive agents can be used as powdered or fibrous fine particles. Among these, carbon black is preferable because it is easy to control conductivity and is economical.

  The elastic layer 3 has a crosslinking agent, a plasticizer, a filler, an extender, a vulcanizing agent, a vulcanization aid, a crosslinking aid, and an antioxidant as long as the function of the above composition is not impaired. Various additives such as an agent, an anti-aging agent and a processing aid can be contained. Among the fillers, examples of the nonconductive filler include silica, quartz powder, titanium oxide, zinc oxide, and calcium carbonate. Examples of the crosslinking agent include di-t-butyl peroxide, 2,5-dimethyl-2,5-di (t-butylperoxy) hexane, and dicumyl peroxide.

  The thickness of the elastic layer 3 can be appropriately selected so as to have a desired elasticity in order to bring the hardness on the surface of the resin layer 4 to an optimum range, and is preferably 2.0 to 6.0 mm. Furthermore, you may have a functional layer which has functions, such as an easily charged property or friction resistance, between the elastic layer 3 and the resin layer 4. FIG.

  The shaft core 2 used in the developing roller 1P to which the porous resin particles of the present invention are attached has a strength capable of supporting the upper resin layer 4 or the elastic layer 3, and acts as an electrode for the resin layer 4 or the elastic layer 3. It has electrical conductivity. Examples of the material of the shaft core 2 include stainless steel (SUS), aluminum, copper, iron and alloys containing those metals, iron plated with chromium or nickel, and conductive synthetic resin. it can. Furthermore, the metal shaft core may be subjected to rust prevention treatment such as oxidation treatment.

  The shape of the shaft core 2 is preferably a columnar shape, but may be a cylindrical shape, and the surface may be primed as necessary. The outer diameter of the axial core body 2 can mention the range of 4 mm-10 mm. The end portion of the shaft core body 2 is preferably subjected to D-cut and oval cut processing in order to impart rotational torque to the developing roller.

  As a manufacturing method of the developing roller 1P to which the porous resin particles of the present invention are attached, first, the resin layer 4 is formed on the shaft core body 2 or the elastic layer 3 formed on the shaft core body 2.

  As a method for forming the elastic layer 3 on the shaft core 2, a mold forming method, an extrusion forming method, an injection forming method, and a coating forming method can be used. The surface of the elastic layer 3 can be modified by a surface modification method such as surface polishing, corona treatment, frame treatment, or excimer treatment in order to improve adhesion to the resin layer 4.

  The resin layer 4 is preferably formed by a coating molding method. As the coating molding method, dip coating, spray coating or roll coating can be used.

  When dip coating is used for the above formation, as an example, a coating apparatus as shown in FIG. 3 can be used. Although FIG. 3 shows a case where the shaft core body 2 provided with the elastic layer 3 is dip coated as an example, the shaft core body 2 not provided with the elastic layer 3 may be used for direct dip coating. Good.

  3 has an inner diameter slightly larger than the outer diameter of the shaft core body 2 provided with the elastic layer 3, and has a depth that allows the shaft core body 2 provided with the elastic layer 3 to be immersed in the axial direction. A cylindrical immersion tank 27 is provided. An annular liquid receiving portion is provided on the outer periphery of the upper edge of the immersion tank 27 and is connected to the stirring tank 29. The bottom of the immersion tank 27 is connected to the stirring tank 29.

  The paint in the stirring tank 29 is sent to the bottom of the immersion tank 27 by the liquid feed pump 28. The paint overflows from the upper end of the immersion tank 27 and returns to the agitation tank 29 via the liquid receiving part on the outer periphery of the upper edge of the immersion tank 27. The shaft core body 2 provided with the elastic layer 3 is fixed perpendicularly to the lifting device 30, immersed in the immersion tank 27 and pulled up to form a coating film.

  After the coating film is formed, the shaft core body 2 provided with the elastic layer 3 is removed from the lifting device 30, and the resin coating film is dried and then heat-cured to form the resin layer 4. Heat curing is performed for 60 to 300 minutes in an environment at a temperature of 120 to 180 ° C. Thereby, a developing roller is obtained.

  The method for adhering the porous resin particles 5 to the developing roller is not particularly limited, but the porous resin particles 5 are soaked in sponge, cloth, paper, and rubbed against the surface of the resin layer 4. The method of making it adhere by is mentioned. Further, there is a method in which a coating material in which the porous resin particles 5 are dispersed in a solvent is prepared, and this coating material is applied and dried by dipping or spraying.

  Among these, as shown in the schematic configuration diagram of FIG. 4, the surface of the resin layer 4 of the developing roller is pressed against the sponge roller R previously containing an appropriate amount of porous resin particles 5, and the sponge roller R and the developing roller are rotated. Rub. Thereby, the method of attaching porous resin particles on the resin layer 4 can be used. At that time, the adhesion amount of the porous resin particles 5 can be controlled by the penetration amount of the sponge roller R into the developing roller, the rubbing speed, and the rubbing time.

  The electrophotographic image forming apparatus of the present invention supplies a toner to the surface of the latent image carrier to form a toner image, and forms a toner on the developing roller into a thin film so that the amount of toner on the developing roller is constant. A developer amount regulating member. The developing roller is a developing roller 1P to which the porous resin particles are attached.

  As an example thereof, a tandem color electrophotographic image forming apparatus shown in the schematic configuration diagram of FIG. 5 can be given. The color electrophotographic image forming apparatus shown in FIG. 5 includes image forming units a to d that are provided for each color toner of yellow toner, magenta toner, cyan toner, and black toner. Each image forming unit is provided with a photoreceptor 6 as an electrostatic latent image carrier that rotates in the direction of the arrow. Around each photoconductor 6, there is a charging device 12 for uniformly charging the photoconductor 6, and exposure means for irradiating the uniformly charged photoconductor 6 with a laser beam 11 to form an electrostatic latent image. A developing device 10 is provided that supplies toner to the photoreceptor 6 on which the electrostatic latent image has been formed to develop the electrostatic latent image.

  On the other hand, a transfer conveyance belt 21 that conveys a recording material 23 such as paper or an OHP sheet supplied by a paper supply roller 24 is suspended from a driving roller 17, a driven roller 22, and a tension roller 20. The transfer conveyance belt 21 is charged with the charge of the suction bias power supply 26 via the suction roller 25, and transports the recording material 23 by electrostatically adhering it to the surface.

  A transfer bias power source 19 is provided for applying a charge for transferring the toner image on the photoreceptor 6 of each image forming unit to the recording material 23 conveyed by the transfer conveyance belt 21. The transfer bias is applied via a transfer roller 18 disposed on the back surface of the transfer conveyance belt 21. The toner images of the respective colors formed in the image forming units a to d are sequentially superimposed and transferred onto a recording material 23 conveyed by a transfer conveying belt 21 that is moved in synchronization with the image forming unit.

  Further, the color electrophotographic image forming apparatus includes a fixing device 16 that fixes the toner image superimposed and transferred onto the recording material 23 by heating or the like, and a conveying device that discharges the image-formed recording material 23 outside the device (not shown). ) Is provided.

  On the other hand, each image forming unit is provided with a cleaning device 13 having a cleaning blade that removes transfer residual toner that is not transferred onto each photoconductor 6 and cleans the surface. Further, a waste developer container for storing toner scraped off from the photoreceptor 6 is provided. The cleaned photosensitive member 6 is set in an image-formable state and stands by.

  The developing device 10 provided in each of the image forming units is provided with a developer container 8 containing a non-magnetic developer as a one-component developer. Further, a developing roller 1P, which is installed so as to close the opening of the developer container 8 and to which porous resin particles adhere so as to face the photoreceptor 6 at a portion exposed from the developer container 8, is provided.

  A developer supply roller 7 is provided in the developer container 8 to supply toner to the developing roller 1P and at the same time to scrape off residual toner that has not been used on the developing roller 1P after development. In addition, a developer amount regulating member 9 for forming the toner on the developing roller 1P in a thin film and frictionally charging is provided. The developer supply roller 7 and the developer amount regulating member 9 are respectively disposed in contact with the developing roller 1P to which porous resin particles are attached. A blade bias power source 14 is connected to the developer amount regulating member 9, a developing roller bias power source 15 is connected to the developing roller 1P, and charges are respectively applied to the developer amount regulating member 9 and the developing roller 1P during image formation. Applied.

  The developer supply roller 7 is preferably a foam brush body or polyurethane foam on a shaft core body, or a fur brush structure in which fibers such as rayon or polyamide are planted. This is to facilitate the removal of the residual toner on the developing roller 1P to which the porous resin particles after development have adhered.

  In addition, the electrophotographic process cartridge of the present invention includes a developing roller that supplies toner to the surface of the latent image carrier to form a toner image, and a toner on the developing roller is formed in a thin film so that a certain amount of toner on the developing roller A developer amount regulating member. Further, the process cartridge is detachably provided in the electrophotographic image forming apparatus, and the developing roller is a developing roller 1P to which the porous resin particles are attached.

  As an example, the electrophotographic process cartridge shown in the schematic configuration diagram of FIG. 6 can be cited. The electrophotographic process cartridge shown in FIG. 6 includes a developing device 10, a photoreceptor 6, and a cleaning device 13, which are integrated and detachably provided in the electrophotographic image forming apparatus main body. For example, in the color electrophotographic image forming apparatus in FIG. 5, the process cartridge for electrophotography according to the present invention may be used as the image forming unit, and may be detachably incorporated. The developing device 10 may be the same as that described in the electrophotographic image forming apparatus. In addition to the above, the electrophotographic process cartridge of the present invention may be one in which a transfer member for transferring the toner image on the photosensitive member 6 to the recording material 23 is provided integrally with the above members.

  In addition, the measurement of each physical property was performed with the measuring method shown below.

<Method for Measuring Number Average Particle Size of Porous Resin Particles 5>
The number average particle diameter of the porous resin particles 5 is an arithmetic average value of the maximum diameters measured by randomly selecting 200 particles. For measurement of the maximum diameter, FE-SEM (trade name: “S-4800”, Hitachi High-Technology Co., Ltd.) is used for observation and measurement.

<Method for measuring specific surface area of porous resin particles 5>
The specific surface area of the porous resin particles 5 is calculated according to the specific surface area measurement method of JIS Z8830 using a specific surface area meter (trade name: “Autosorb-1”, manufactured by QUANTACHROME). The measurement sample is about 0.1 g, weighed in a cell, and degassed for 12 hours or more at a temperature of 40 ° C. and a vacuum degree of 1.0 × 10 ⁻³ mmHg. Thereafter, nitrogen gas is adsorbed while being cooled with liquid nitrogen, and a value is obtained by a multipoint method. The sampling of the porous resin particles 5 can be performed by directly collecting from the developing roller 1P to which the porous resin particles are attached. Further, when the sampling amount is small with the developing roller 1P to which one porous resin particle is adhered, it is possible to collect from the developing roller 1P to which a plurality of porous resin particles are adhered.

<Method for measuring compressive strength of porous resin particle 5>
The compression hardness of the porous resin particles 5 in the present invention is measured as follows. The measurement environment is a room temperature of 23 ° C. and a relative humidity of 55%, and left in the same environment for 24 hours before the measurement. The particle diameter d (mm) of the porous resin particles 5 is measured with a digital microscope attached to an ultra-micro hardness measuring device (trade name: “ENT-1100”, manufactured by Elionix Co., Ltd.). Next, a flat indenter with a tip of 20 μm square is attached to the ultra-micro hardness measuring apparatus, and a load of 0.001 N per second is added and added. Compression is performed until the particle diameter in the direction in which the load is applied is reduced by 10% from the diameter d (mm), and the load P (N) applied to the planar indenter at this time is measured. The load P (N) applied to the planar indenter is substituted into the following formula 1, and the 10% compression hardness E (MPa) of the porous resin particles 5 is obtained.
E = 2.8P / πd ² (MPa) (Formula 1).

<Measurement method of arithmetic mean circularity of porous resin particle 5>
Using a flow type particle image measuring device “FPIA-2100 type” (trade name, manufactured by Sysmex Corporation), 1000 or more porous resin particles 5 are measured, and the circularity of each of the measured particles is expressed by the following formula 2 Ask for.
Circularity a = L0 / L (Formula 2)
(In Equation 2, L0 represents the circumference of a circle having the same projected area as the particle image, and L is the particle image when image processing is performed at an image processing resolution of 512 × 512 (pixels of 0.3 μm × 0.3 μm). Indicates the perimeter of the).

<Measurement method of adhesion amount of porous resin particles 5 to resin layer surface>
Using an adhesive tape of 10 mm × 10 mm (trade name: “Scotch Mending Tape” (manufactured by Sumitomo 3M Co., Ltd.), any 10 mm × 10 mm porous resin particles 5 on the surface of the developing roller are peeled off. If a large amount of the porous resin particles 5 adheres and cannot be removed at once, a new adhesive tape is prepared and the porous resin particles 5 are peeled off by repeating the same operation. The weight of the porous resin particles 5 thus peeled off is measured, and the weight of the porous resin particles 5 adhering per unit area is calculated from the ratio of the weight and the area (10 mm × 10 mm). In addition, the measurement is performed at 10 points on the surface of the developing roller 1P to which the porous resin particles are adhered, and the arithmetic average value is set as the value of the adhesion amount.

  Hereinafter, the developing roller, the electrophotographic process cartridge, and the electrophotographic image forming apparatus to which the porous resin particles according to the present invention are attached will be described in detail, but the technical scope of the present invention is limited to these. It is not something.

[Preparation of porous resin particles]
[Preparation of porous resin particles 1]
(Oil layer material)
N-butyl acrylate 30 parts by mass diethylene glycol dimethacrylate 20 parts by mass n-hexane 50 parts by mass benzoyl peroxide 0.3 parts by mass (aqueous layer material)
Ion-exchanged water 350 parts by mass Calcium phosphate 6 parts by mass Sodium lauryl sulfate 0.03 parts by mass The above oil layer material and water layer material are mixed, and this mixed solution is mixed with a high-speed stirrer (trade name: “TK homomixer”, special machine Using a chemical industry), stirring and granulation were performed at a stirring rotational speed of 4000 rpm for 10 minutes. Thereafter, the temperature was raised to 65 ° C. while stirring with a paddle stirring blade, and suspension polymerization was performed for 7 hours. After completion of the polymerization, the suspension was cooled to a temperature of 23 ° C., hydrochloric acid was added to dissolve the calcium phosphate as a dispersant, filtered, washed with water, and dried to prepare porous resin particles 1.

[Preparation of porous resin particles 2 to 10]
Porous resin particles 2 to 10 were produced in the same manner as in the production of the porous resin particles 1 except that the materials and the stirring rotation speed of the high-speed stirrer were changed to the conditions shown in Table 1.

[Preparation of porous resin particles 11]
N-butyl acrylate 30 parts by mass Diethylene glycol dimethacrylate 20 parts by mass n-hexane 50 parts by mass A solution in which the above materials were mixed was prepared. The nonionic surfactant (trade name: “Nonipol 400”, manufactured by Sanyo Chemical Industries, Ltd.) 1.5 parts by mass and an anionic surfactant (trade name: “Neogen SC”, Daiichi Kogyo Seiyaku Co., Ltd.) Dispersed and emulsified in 2.5 parts by mass dissolved in 200 parts by mass of ion-exchanged water. Thereby, a monomer emulsion was obtained. To this, 20 parts by mass of ion-exchanged water in which 1 part by mass of ammonium persulfate was dissolved was added while slowly mixing for 10 minutes. After nitrogen substitution, the contents were heated while stirring until the temperature reached 70 ° C. Time emulsion polymerization was carried out. In this way, a primary resin particle dispersion was obtained. Next, 2 parts by mass of an aqueous nitric acid solution having a concentration of 10% by mass of polyaluminum chloride as a flocculant was added to 200 parts by mass of the primary resin particle dispersion. Using a high-speed stirrer (trade name: “TK Homomixer”, manufactured by Tokushu Kika Kogyo Co., Ltd.), the mixture was stirred for 10 minutes at a stirring rotational speed of 4000 rpm to perform secondary particle granulation. Thereafter, the temperature was raised to 55 ° C. while stirring with a paddle stirring blade, and polymerization was performed for 1 hour. Thereafter, the pH in the system was adjusted to 6.0 with a 0.5 mol / liter aqueous sodium hydroxide solution, and then heated to 95 ° C. while stirring was continued. During the temperature rise to 95 ° C., the pH in the system usually drops to 5.0 or less, but here, an aqueous sodium hydroxide solution was added dropwise to keep the pH from being 5.5 or less. . After completion of the reaction, the mixture was cooled, filtered, washed with water, and dried to produce porous resin particles 11.

[Preparation of porous resin particles 12]
Polyamide 6 (molecular weight 1300, manufactured by Ube Industries, Ltd.) was dissolved in m-cresol to obtain 12.5 parts by mass of an m-cresol solution of polyamide 6 having a concentration of 1.0% by mass. Further, a mixed solution of 75 parts by mass of methanol and 12.5 parts by mass of water was added to the m-cresol solution of polyamide 6 while stirring with a magnetic stirrer. Then, it stirred for 2 minutes at the temperature of 23 degreeC. After stirring, the mixture was allowed to stand at a temperature of 23 ° C. for 24 hours to precipitate polyamide particles. By filtering and washing the particles, porous resin particles 12 were produced.

[Preparation of non-porous resin particles H1]
In the production of the porous resin particles 1, non-porous resin particles H1 were produced in the same manner except that the materials and the stirring rotation speed of the high-speed stirrer were changed to the conditions shown in Table 1.

(Production roller development)
A primer (trade name: “DY35-051”, manufactured by Toray Dow Corning Co., Ltd.) is applied to a shaft core made of SUS304 having an outer diameter of 8 mm and a length of 280 mm, and concentrically in a cylindrical mold having an inner diameter of 16 mm. It installed so that it might become. The following materials were mixed with 100.0 parts by mass of a liquid silicone rubber material (trade name: “SE6724A / B”, manufactured by Toray Dow Corning Co., Ltd.) as an elastic layer to prepare an addition-type silicone rubber composition. . 35.0 parts by mass of carbon black (trade name: “Toka Black # 7360SB”, manufactured by Tokai Carbon Co., Ltd.), 0.2 parts by mass of silica powder as a heat resistance imparting agent, and 0.1 parts by mass of platinum catalyst Department. The addition type silicone rubber composition was poured into a mold. After heat molding at a temperature of 130 ° C. for 20 minutes, the mold was cooled to a temperature of 50 ° C., and the elastic layer integrated with the shaft core body was taken out from the mold. Next, the elastic layer integrated with the shaft core was heated at a temperature of 200 ° C. for 2 hours to complete the curing reaction, and an elastic layer having a thickness of 4 mm was formed on the shaft core.

  Polytetramethylene glycol (trade name: “PolyTHF”, manufactured by BASF) 100 parts by weight of isocyanate (trade name: “Millionate MT” (MDI), manufactured by Nippon Polyurethane Industry Co., Ltd.) 14.0 parts by weight of methyl ethyl ketone (MEK) Mixed in solvent. The reaction was performed at a temperature of 80 ° C. for 3 hours under a nitrogen atmosphere to obtain a polyurethane polyol prepolymer.

  100 parts by mass of the polyurethane polyol prepolymer and 41.8 parts by mass of isocyanate (trade name: “Coronate 2521” (urethane-modified MDI), manufactured by Nippon Polyurethane Co., Ltd.) are added, and the value of [NCO] / [OH] is 1.1. Furthermore, an appropriate amount of carbon black (trade name: “MA100”, manufactured by Mitsubishi Chemical Corporation) was added to adjust the resistance value. 15 parts by mass of polyurethane resin particles (trade name: “Art Pearl C800 transparent (φ8 μm)”, manufactured by Negami Kogyo Co., Ltd.) are added to the above raw material mixture solution to which an organic solvent is added to adjust the solid content to 25% by mass. The material solution stirred and dispersed in was used as a raw material liquid for the resin layer.

  The obtained raw material solution for the resin layer was applied to the outer periphery of the previously molded elastic layer by dipping so as to have a film thickness of 8.5 μm, dried in an oven at a temperature of 80 ° C. for 15 minutes, and then 2 in an oven at a temperature of 140 ° C. The developing roller was produced by time curing.

  As a result of measuring the center line average surface roughness of the surface of the resin layer, the developing roller was 1.25 μm.

  The centerline average roughness Ra was a value determined according to JIS B0601: 1994 using a surface roughness meter (trade name: “Surfcoder SE-3400”, manufactured by Kosaka Laboratory Ltd.). . As specific measurement conditions, a stylus with a radius of 2 μm was used, the pressing pressure was 0.7 mN, the measurement speed was 0.3 mm / sec, the measurement magnification was 5000 times, the cutoff wavelength was 0.8 mm, and the measurement length was 2.5 mm. , 3 points in the circumferential direction, 3 points in the axial direction, and a value obtained by arithmetic averaging of 9 points in total.

  The hardness of the developing roller was 32.0 points when measured with a rubber hardness meter (trade name: “Micro Rubber Hardness Meter MD-1”). For measurement, a cylindrical needle having a diameter of 0.16 mm was used. Moreover, the value calculated | required by the arithmetic mean of 3 points | pieces of the circumferential direction, 3 points | pieces of an axial direction, and nine points in total was made into rubber hardness.

[Example 1]
(Adhesion of porous resin particles)
A “Cartridge for Laser Beam Printer LBP5500” (trade name) manufactured by Canon Inc. having the configuration shown in FIG. 6 was disassembled, and the developing device was separated, the toner in the developing device was removed, and the developing roller was removed. Next, the developer container of the developing device was filled with the porous resin particles 1 to prepare a modified developing device for attaching porous resin particles. The developed developing device was attached to this modified developing device, and the porous resin particles 1 were adhered to the surface of the resin layer by being driven to rotate for 10 seconds, thereby producing a developing roller to which the porous resin particles adhered. At that time, the rotational driving speed of the developing roller was 120 rpm. At this time, as the developer supply roller in the modified developing device, a sponge roller having a polyurethane resin foam on the core metal and having a foam cell number of 80/25 mm was used. The amount of penetration of the sponge roller into the developing roller was 1.5 mm, the rotation direction was set to the direction shown in FIG. 4, and the rotation speed was set to 64% of the developing roller. Each physical property was measured by the method defined above. The results are shown in Table 2.

  Next, using the developing roller to which the porous resin particles are adhered, under a high temperature and high humidity (abbreviated as H / H) at a temperature of 32 ° C. and a humidity of 85% RH, and at a normal temperature and humidity of a temperature of 23 ° C. and a humidity of 55% (RH). N / N (hereinafter abbreviated as N / N). Evaluation was performed by the following method. The results are shown in Table 2.

<< Image evaluation >>
The developing roller having the porous resin particles adhered thereto was loaded into a “Cyan cartridge for laser beam printer LBP5500” (trade name) manufactured by Canon Inc., and allowed to stand for 24 hours in both H / H and N / N environments. Thereafter, the cartridges were loaded into “LBP5500” (trade name, manufactured by Canon Inc.) main bodies in both environments, and image defects due to fixation of the developer or porous resin particles were evaluated. For image evaluation, 30 halftone images were output at a speed of 17 sheets / minute, and the following standards were used for the 1st to 30th images. The results are shown in Table 2.
A: No image defect due to the fixed marks of the developer or porous resin particles is observed.
B: Up to the fifth sheet, image defects due to the fixed marks of the developer or porous resin particles are observed, but not thereafter.
C: Image defects due to the fixed marks of the developer or porous resin particles are observed up to the 10th sheet, but not thereafter.
D: Up to the fifteenth sheet, image defects due to the fixed marks of the developer or porous resin particles are observed, but not thereafter.
E: Up to the 20th sheet, an image defect due to the fixed marks of the developer or porous resin particles is observed, but not thereafter.

[Examples 2 to 5]
A developing roller having porous resin particles adhered thereto was prepared in the same manner as in Example 1 except that the porous resin particles 2 to 5 were used. Further, physical property measurement and image evaluation were performed in the same manner as in Example 1. The results are shown in Table 2.

[Comparative Example 1]
A developing roller to which the resin particles adhered was prepared in the same manner as in Example 1 except that the nonporous resin particles H1 were used. Further, physical property measurement and image evaluation were performed in the same manner as in Example 1. When the roller after output was confirmed, toner adhesion was observed. The results are shown in Table 2.

[Comparative Example 2]
In Example 1, the developing roller was used as it was without using porous resin particles. Image evaluation was performed in the same manner as in Example 1. As a result, since porous resin particles were not attached, the driving torque at the time of startup increased, resulting in torque fluctuation, and a banding image was output from the first sheet, and proper output could not be performed. Further, when the roller after the output was confirmed, toner adhesion was observed.

  From the above results, it was found that good images can be obtained by attaching the porous resin particles to the developing roller.

[Examples 6 to 9]
A developing roller having porous resin particles adhered thereto was prepared in the same manner as in Example 1 except that the porous resin particles 6 to 9 were used. Further, physical property measurement and image evaluation were performed in the same manner as in Example 1. The results are shown in Table 2. From the above results and the results of Example 1, it was found that a better image can be obtained by setting the compressive strength of the porous resin particles within the range of the present invention.

[Examples 10 to 12]
A developing roller having porous resin particles adhered thereto was prepared in the same manner as in Example 1 except that the porous resin particles 10 to 12 were used. Further, physical property measurement and image evaluation were performed in the same manner as in Example 1. The results are shown in Table 2. From the above results, it was found that a better image can be obtained by setting the arithmetic average circularity of the porous resin particles in a preferable range. Moreover, it turned out that a more favorable image is obtained by making a porous resin particle into a porous acrylic resin particle.

[Example 13]
A developing roller having porous resin particles adhered thereto was prepared in the same manner as in Example 1 except that the adhesion time was 2 seconds in the porous resin particle adhesion step. Further, physical property measurement and image evaluation were performed in the same manner as in Example 1. The results are shown in Table 2.

[Example 14]
A developing roller having porous resin particles adhered thereto was prepared in the same manner as in Example 1 except that the adhesion time was 4 seconds in the porous resin particle adhesion step. Further, physical property measurement and image evaluation were performed in the same manner as in Example 1. The results are shown in Table 2.

[Example 15]
A developing roller having porous resin particles adhered thereto was prepared in the same manner as in Example 1 except that the adhesion time was 30 seconds in the porous resin particle adhesion step. Further, physical property measurement and image evaluation were performed in the same manner as in Example 1. The results are shown in Table 2.

[Example 16]
A developing roller having porous resin particles adhered thereto was prepared in the same manner as in Example 1 except that the adhesion time of the porous resin particles was 60 seconds. Further, physical property measurement and image evaluation were performed in the same manner as in Example 1. The results are shown in Table 2. From the results of Examples 13 to 16 and the result of Example 1, it was found that a better image can be obtained by setting the adhesion amount of the porous resin fine particles within a preferable range.

[Comparative Example 3]
A developing roller having resin particles adhered thereto was prepared in the same manner as in Example 1 except that a spherical polyamide powder (trade name: “SP-500”, manufactured by Toray Industries, Inc.) was used instead of the porous resin particles 1. . Further, physical property measurement and image evaluation were performed in the same manner as in Example 1. Image defects due to the fixation of the true spherical polyamide powder occurred in an H / H environment. The results are shown in Table 2.

[Comparative Example 4]
A developing roller having resin particles adhered thereto was prepared in the same manner as in Example 1 except that PTFE powder (trade name: “Fluon PTFE L150J”, Asahi Glass Co., Ltd.) was used instead of the porous resin particles 1. Further, physical property measurement and image evaluation were performed in the same manner as in Example 1. Image defects due to toner fixation occurred in an H / H environment. The results are shown in Table 2.

  From the above results, by using the developing roller to which the porous resin particles of the present invention are attached, the frictional force with other members is reduced even under high temperature and high humidity, and the developer and the porous resin particles are fixed. It is possible to suppress image defects caused by the above.

It is a schematic side view which shows an example of the developing roller to which the porous resin particle of this invention adhered. It is a schematic side view which shows an example of the developing roller to which the porous resin particle of this invention adhered. It is a schematic block diagram which shows an example of the manufacturing apparatus of the developing roller of this invention. It is a schematic block diagram which shows an example of the adhesion method of the porous resin particle of this invention. 1 is a schematic configuration diagram illustrating an example of an electrophotographic image forming apparatus of the present invention. 1 is a schematic configuration diagram showing an example of an electrophotographic process cartridge of the present invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Developing roller 1P Developing roller 2 with porous resin particles adhered Shaft core body 3 Elastic layer 4 Resin layer 5 Porous resin particles 6 Photoconductor 7 Developer supply roller 8 Developer container 9 Developer amount regulating member 10 Developing device 11 Laser beam 12 Charging device 13 Cleaning device 14 Blade bias power source 15 Developing roller bias power source 16 Fixing device 17 Driving roller 18 Transfer roller 19 Transfer bias power source 20 Tension roller 21 Transfer conveyance belt 22 Drive roller 23 Recording material 24 Paper feed roller 25 Adsorption roller 26 Adsorption bias power supply 27 Immersion tank 28 Liquid feed pump 29 Stirring tank 30 Lifting device R Sponge roller

Claims (8)

A shaft core, and a resin layer containing a polyurethane resin provided on the outer periphery of the shaft core,
A developing roller, wherein porous resin particles are detachably attached to the surface of the resin layer. The developing roller according to claim 1, wherein the porous resin particles are porous resin particles having a number average particle diameter of 5 to 50 μm and a specific surface area of ² to 100 m ² / g.   The developing roller according to claim 1, wherein the porous resin particles have a compressive strength of 1.0 to 5.0 MPa.   The developing roller according to any one of claims 1 to 3, wherein the arithmetic average circularity of the porous resin particles is 0.96 to 1.00.   The developing roller according to claim 1, wherein the porous resin particles are porous acrylic resin particles. The developing roller according to claim 1, wherein the porous resin particles are attached to the surface of the resin layer at a density of 0.10 to 1.00 mg / cm ² . A developing roller that supplies toner to the surface of the latent image carrier to form a toner image, and a developer amount regulating member that forms the toner on the developing roller in a thin film and makes the toner on the developing roller a constant amount In an electrophotographic process cartridge that is detachable from an electrophotographic image forming apparatus,
An electrophotographic process cartridge, wherein the developing roller is the developing roller according to any one of claims 1 to 6. A developing roller that supplies toner to the surface of the latent image carrier to form a toner image, and a developer amount regulating member that forms the toner on the developing roller in a thin film and makes the toner on the developing roller a constant amount In an electrophotographic image forming apparatus,
An image forming apparatus for electrophotography, wherein the developing roller is the developing roller according to claim 1.