JP2011028044A - Electrophotographic process cartridge - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electrophotographic process cartridge hardly causing plastic deformation on the surface of a developing roller, irrespective of a long-term neglect under a high temperature/humidity condition. <P>SOLUTION: The electrophotographic process cartridge includes: the developing roller having an elastic layer; and a toner amount-regulating member for forming a toner layer on the surface of the developing roller. Hollow resin particles are deposited on the surface of the developing roller, and the developing roller and the toner amount-regulating member come into contact with each other through the hollow resin particles. By rotating the developing roller, the hollow resin particles drop off the surface of the developing roller. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to an electrophotographic process cartridge and a developing method used in an image forming apparatus such as a copying machine or a laser printer.

  As disclosed in Patent Document 1, a toner amount regulating member is normally in contact with the developing roller, but there are the following problems caused by this. That is, when the electrophotographic process cartridge is placed in a high temperature and high humidity environment during transportation or storage, plastic deformation of the surface of the developing roller is promoted at a position where the toner amount regulating member is in contact. If a developing roller whose surface is greatly plastically deformed is used, a strip-like streak may occur in the electrophotographic image due to the plastically deformed portion.

Japanese Patent Application Laid-Open No. 08-179619

  An object of the present invention is to provide an electrophotographic process cartridge that hardly causes plastic deformation on the surface of a developing roller even when left under a high temperature and high humidity condition for a long period of time.

An electrophotographic process cartridge according to an aspect of the present invention is an electrophotographic process cartridge including a developing roller and a toner amount regulating member for forming a toner layer on the developing roller,
The developing roller has hollow resin particles attached to the surface thereof, the developing roller and the toner amount regulating member are in contact with each other through the hollow resin particles, and
The hollow resin particles fall off the surface by rotating the developing roller.

  According to the present invention, since the developing roller and the toner amount regulating member are in contact with each other through the hollow resin particles when left for a long time (such as during transportation), it is effective that the surface of the developing roller is plastically deformed. Can be suppressed. Further, since the hollow resin particles are easily removed from the surface of the developing roller by being scraped off by the toner amount regulating member as the developing roller rotates, the formation of the electrophotographic image is hardly affected.

It is sectional drawing of the developing roller which concerns on this invention. 1 is a schematic view of an electrophotographic process cartridge according to the present invention. It is explanatory drawing of the image forming apparatus which concerns on this invention. It is explanatory drawing of the manufacturing method of the developing roller which concerns on this invention. It is explanatory drawing of the hollow resin particle which concerns on this invention. It is explanatory drawing of an apparatus which measures the electrical resistance of the developing roller which concerns on this invention.

  The present inventors relieve the toner amount regulating member by dispersing the contact pressure against the developing roller by interposing the hollow resin particles having low hardness between the developing roller and the toner amount regulating member. As a result, it has been found that the depth of penetration of the toner amount regulating member into the developing roller becomes shallow, and plastic deformation of the developing roller can be reduced. Further, due to the high resilience of the hollow resin particles, the toner amount is easily scraped off with the rotation of the developing roller. As a result, it has been found that image defects caused by particles remaining on the developing roller can be suppressed. Hereinafter, the present invention will be described in more detail.

(Development roller)
As the developing roller, as shown in FIG. 1, a roller having an elastic layer 2 provided around the conductive shaft 1 and having a resin layer 3 as a surface layer on the outer periphery thereof can be used. .

In the present invention, as the conductive shaft 1, a cylindrical body having an outer diameter of 4 to 10 mm made of aluminum, iron, or stainless steel (SUS) is used. The elastic layer 2 provided around the conductive shaft 1 is made of silicone rubber, EPDM or urethane elastomer, or other resin. The elastic layer 2 is prepared by blending an electron conductive material or an ionic conductive material and adjusting the volume resistivity to 10 ^{3 to} 10 ¹⁰ Ωcm, preferably 10 ^{4 to} 10 ⁸ Ωcm.

  The following can also be used as the base material of the elastic layer 2. Natural rubber, butyl rubber, nitrile rubber, polyisoprene rubber, polybutadiene rubber, styrene-butadiene rubber, ethylene-propylene rubber, chloroprene rubber, acrylic rubber, and mixtures thereof. Of these, silicone rubber is preferably used because of its unique properties of low hardness and high resilience.

  A resin layer 3 as a surface layer is formed on the outer periphery of the elastic layer 2. Specifically, the following can be used as the binder resin of the resin layer 3. Urethane resin, epoxy resin, diallyl phthalate resin, polyethylene resin, polycarbonate resin, fluorine resin, polypropylene resin, urea resin, melamine resin, silicon resin, polyester resin, styrene resin, acrylic resin, vinyl acetate resin, phenol resin, polyamide resin , Fiber based resins, vinyl chloride resins, silicone resins, water based resins, and mixtures thereof. Among these, polyurethane resin is preferably used because of the charging property and abrasion resistance of the toner. In particular, a polyether polyurethane resin that can reduce the hardness of the film and that has a particularly high chargeability of 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. In addition, these polyol components may be prepolymers that are chain-extended with an isocyanate such as 2,4-tolylene diisocyanate (TDI), 1,4 diphenylmethane diisocyanate (MDI), isophorone diisocyanate (IPDI) as necessary.

  Specific examples of the isocyanate compound to be reacted with these polyol components include the following. Aliphatic polyisocyanates such as ethylene diisocyanate, 1,6-hexamethylene diisocyanate (HDI), isophorone diisocyanate (IPDI), cyclohexane 1,3-diisocyanate, cyclohexane 1,4-diisocyanate, 2,4 -Tolylene diisocyanate, aromatic polyisocyanate of 2,6-tolylene diisocyanate (TDI), diphenylmethane diisocyanate (MDI), modified products and copolymers thereof, and block bodies thereof.

  Roughening particles can be added to the resin layer 3 for the purpose of roughening the surface of the developing roller. Specific examples of the coarse particles include the following. Rubber particles such as EPDM, NBR, SBR, CR, silicone rubber; Elastomer particles such as polystyrene, polyolefin, polyvinyl chloride, polyurethane, polyester, polyamide-based thermoplastic elastomer (TPE); PMMA, urethane resin, fluororesin, silicone Resin particles such as resin, phenol resin, naphthalene resin, furan resin, xylene resin, divinylbenzene polymer, styrene-divinylbenzene copolymer, polyacrylonitrile resin. These can be used alone or in combination of two or more.

  The developing roller has a conductive shaft body 1, an elastic layer 2, and a resin layer 3. Here, the method for forming the elastic layer 2 is not particularly limited. However, since the elastic layer 2 can be formed with high dimensional accuracy, a method of forming an elastic layer by injecting an elastic material into the mold is preferable.

  The formation method of the resin layer 3 is not particularly limited, but a method of coating a coating on the elastic layer 2 is preferable because a stable surface shape can be obtained. In view of excellent production stability, dip coating in which the paint overflows from the upper end of the dip tank as described in JP-A-57-5047 is preferred. FIG. 4 is a schematic diagram of overflow type dip coating. A cylindrical immersion tank 25 has an inner diameter larger than the outer shape of the roller and a depth larger than the axial length of the roller. An annular liquid receiving portion is provided on the outer periphery of the upper edge of the immersion tank 25 and is connected to the stirring tank 27. The bottom of the immersion tank 25 is connected to the stirring tank 27, and the paint in the stirring tank 27 is sent to the bottom of the immersion tank 25 by the liquid feed pump 26. The paint sent to the bottom of the immersion tank 25 overflows from the upper end of the immersion tank 25 and returns to the agitation tank 27 through the liquid receiving portion on the outer periphery of the upper edge of the immersion tank 25. The roller member provided with the elastic layer 2 on the conductive shaft 1 is fixed vertically to the elevating device 28, immersed in the immersion tank 25, and then pulled up to form the resin layer 3.

  Specific examples of the electronic conductive material used for adjusting the electric resistance of the elastic layer 2 and the resin layer 3 in the present invention include the following. Ketjen Black EC, conductive carbon of acetylene black, SAF, ISAF, HAF, FEF, GPF, SRF, FT, MT rubber carbon, oxidized carbon (ink) carbon, copper, silver, germanium Metals and metal oxides. Among these, carbon black is preferable because the conductivity can be controlled with a small amount. These conductive powders are usually suitably used in the range of 0.5 to 50 parts by weight, particularly 1 to 30 parts by weight with respect to 100 parts by weight of the base material. Moreover, the following are mentioned as an ion conductive substance used as a conductive material. Inorganic ionic conductive materials such as sodium perchlorate, lithium perchlorate, calcium perchlorate, and lithium chloride, and organic ionic conductive materials such as modified aliphatic dimethylammonium ethosulphate and stearylammonium acetate.

  The method for dispersing the resistance adjusting material in the material forming the elastic layer 2 is not particularly limited, and can be dispersed using a known device such as a roll, a Banbury mixer, or a pressure kneader. Further, the method for dispersing the resistance adjuster in the coating material for forming the resin layer 3 is not particularly limited. For example, the resistance modifier and the porous resin particles may be added to a solution obtained by dissolving a resin material in an appropriate organic solvent, and dispersed using a known apparatus such as a sand grinder, a sand mill, or a ball mill. it can.

The electric resistance of the developing roller is preferably 1 × 10 ⁵ Ω or more and 1 × 10 ⁷ Ω or less. That is, when used in a process in which a bias is applied to the toner amount regulating member, blade bias leakage is likely to occur when the electrical resistance value is less than 1 × 10 ⁵ Ω, and the electrical resistance value exceeds 1 × 10 ⁷ Ω. In some cases, a development negative ghost is likely to occur.

(Toner amount regulating member)
The toner amount regulating member is for forming a toner layer on the surface of the developing roller. The material is not particularly limited. When a bias is applied to the toner amount regulating member, the toner amount regulating member is preferably conductive, and more preferably a metal such as phosphor bronze or stainless steel. It is preferable that the contact pressure of the toner amount regulating member with respect to the developing roller is 5 g / cm or more and 35 g / cm or less because the toner can be more uniformly applied on the developing roller. In the present invention, it is necessary to interpose hollow resin particles in the contact area between the developing roller and the toner amount regulating member. FIG. 5 is a schematic diagram of hollow resin particles. The substantially spherical hollow resin particles 29 are compressed by the contact pressure of the toner amount regulating member 9, and the cross section is deformed into an ellipse. By this deformation, the contact pressure is dispersed in a direction approximately 90 ° with respect to the compression direction, and the contact pressure applied to the developing roller is relieved. This relaxation action can reduce plastic deformation of the developing roller due to the contact of the toner amount regulating member.

  When the polymer constituting the outer shell 30 of the hollow resin particles is subjected to pressure or heat, it undergoes elastic deformation and plastic deformation due to displacement between polymer molecules. On the other hand, the gas constituting the void only undergoes elastic deformation and does not cause plastic deformation. Therefore, by making the particles hollow, it is possible to reduce the ratio of plastic deformation in the entire particles. In addition, when the pressure applied from the outside is released, the hollow resin particles push the outer shell 29 of the hollow resin particles from the inside by the pressure of the internal gas, so that the force to try to restore the shape of the outer shell 29 to its original shape. Work. For these reasons, the hollow resin particles have higher resilience than the solid particles. As a result, the hollow resin particles interposed in the contact area between the toner amount regulating member and the developing roller are removed from the elliptical shape when the developing roller rotates when the developing roller rotates when the cartridge is used. Return to 29. Thereafter, since the hollow resin particles 29 have returned to the original shape, they do not enter the contact area and are easily scraped off by the toner amount regulating member and fall off from the developing roller. Therefore, streak-like image defects that occur when the hollow resin particles are sandwiched between the contact regions can be prevented. On the other hand, in the case of solid particles, in the contact area between the developing roller and the toner amount regulating member, plastic deformation is large, and it is difficult to return to the original shape. For this reason, solid particles are not easily scraped by the toner amount regulating member when the developing roller rotates, which may cause image defects.

The micro compression hardness of the hollow resin particles is preferably 0.6 × 10 ⁻⁴ N / μm or more and 1.5 × 10 ⁻⁴ N / μm or less. This is because when the hollow resin particles are present in the contact area between the developing roller and the toner amount regulating member, the hollow resin particles are distorted into an elliptical shape by the contact pressure, and a sufficient effect of relaxing the contact pressure can be obtained.

The adhesion amount (density) of the hollow resin particles on the developing roller is preferably 5 × 10 ⁻⁹ mg / cm ² or more and 4 × 10 ⁻⁸ mg / cm ² or less. This is because the contact pressure of the toner amount regulating member can be sufficiently relaxed by the hollow resin particles being interposed, and plastic deformation due to the toner amount regulating member entering the developing roller can be reduced.

  Here, the hollow resin particles in the present invention are particles composed of an outer shell and one void, and preferably have a porosity of 50% or more with respect to the volume of the entire particle. When the porosity with respect to the volume of the whole particle | grain is 50% or more, the ratio of the plastic deformation to the whole particle | grain is low, and resilience becomes high. This is preferable because the hollow resin particles easily fall off from the developing roller.

  In addition, the material of the hollow resin particles in the present invention may be any of acrylic, urethane, silicone and the like as long as the material satisfies the range of the micro compression hardness, and is not limited.

  Moreover, it is preferable that the arithmetic mean particle diameter of the hollow resin particle in this invention is 50 micrometers or more and 150 micrometers. When the arithmetic average particle diameter is less than 50 μm, it is difficult to obtain the effect of reducing the penetration of the toner amount regulating member. On the other hand, when the diameter is larger than 150 μm, it becomes difficult to fill the hollow resin particles with a sufficient filling density in the contact area between the developing roller and the toner amount regulating member.

(Method of contacting the developing roller and the toner amount regulating member through the hollow resin particles)
Any method may be used as long as the developing roller and the toner amount regulating member are in contact with each other through the powder. However, after the powder is attached to the surface of the developing roller, the developing roller and the toner amount regulating member are used. The method of abutting is the simplest.

(Electrophotographic process cartridge and developing method)
FIG. 2 shows a schematic configuration diagram of the electrophotographic process cartridge of the present invention. FIG. 3 is a schematic configuration diagram of an image forming apparatus used in the electrophotographic process cartridge of the present invention.

  The electrophotographic process cartridge shown in FIG. 2 includes a developing device 10 and a charging member 12. The developing device 10 includes a developing roller 6, a toner applying member 7, toner 8 and a toner amount regulating member 9 having a mechanism capable of applying a blade bias. The charging device 12 includes a photosensitive drum 5, a cleaning blade 14, and a waste toner container 13. The electrophotographic process cartridge is detachably attached to the image forming apparatus. The developing device 10 includes a toner container containing non-magnetic one-component toner 8 and a developing roller 6 positioned in an opening extending in the longitudinal direction in the toner container and facing the photosensitive drum 5. The electrostatic latent image on the drum 5 is developed and visualized. The photosensitive drum 5 rotates in the direction of the arrow, is uniformly charged by a charging member 12 for charging the photosensitive drum 5, and the surface thereof is exposed by laser light 11 which is an exposure means for writing an electrostatic latent image on the photosensitive drum 5. An electrostatic latent image is formed. The electrostatic latent image is developed and visualized by applying toner by the developing device 10 disposed in contact with the photosensitive drum 5. The development is so-called reversal development in which a toner image is formed on the exposed portion. The visualized toner image on the photosensitive drum 5 is transferred to the recording paper 22 by the transfer roller 17. The recording paper 22 to which the toner image has been transferred is subjected to fixing processing by the fixing device 15 and is discharged out of the device, thus completing the printing operation. On the other hand, the toner remaining on the photosensitive drum 5 without being transferred is scraped off by the cleaning blade 14 for cleaning the surface of the photosensitive drum 5 and stored in the waste toner container 13. The photosensitive drum 5 cleaned in this way is ready for the next image formation. The structure of the toner application member 7 is a sponge structure or a fur brush structure in which fibers such as rayon and polyamide are planted on the shaft core in terms of supplying the toner 8 to the developing roller 6 and stripping off the undeveloped toner. Is preferred. For example, an elastic roller in which polyurethane foam is provided on the shaft core can be used. The contact width of the toner application member 7 with respect to the developing roller 6 is preferably 1 to 8 mm, and it is preferable that the developing roller 6 has a relative speed at the contact portion.

  Hereafter, the measuring method in this invention is shown.

<Measurement method of volume resistivity>
The elastic layer material is formed into a sheet shape, heated at a temperature of 130 ° C. for 20 minutes to form two rubber sheets having a thickness of 2.0 mm, and then heated at a temperature of 200 ° C. for 4 hours. The rubber sheet was left in an environment of a temperature of 23 ° C./humidity of 55% RH for 24 hours or more.

  A value obtained by the following method can be adopted as the volume resistivity.

・ Resistance meter: Digital ultra-high resistance / micro ammeter (trade name 8340A, manufactured by ADC Corporation);
Measurement mode: Program mode 5 (charge and major 30 seconds, discharge 10 seconds);
-Applied voltage: 100 (V);
Sample box: Resistivity chamber 42 (manufactured by ADC), the main electrode is a metal having a diameter of 22 mm and a thickness of 10 mm, and the guard ring electrode is a metal having an inner diameter of 41 mm, an outer diameter of 49 mm, and a thickness of 10 mm.

  Test piece: A test piece having a diameter of 56 mm is cut out from a 2.0 mm-thick rubber sheet produced by the above method. On one side of the cut-out test piece, a vapor deposition film electrode (back electrode) is provided by performing Pt—Pd vapor deposition on the entire surface, and a main electrode film having a diameter of 25 mm is formed on the other surface by the same Pt—Pd vapor deposition film. A guard ring electrode film having an inner diameter of 38 mm and an outer diameter of 50 mm is provided concentrically. The Pt—Pd vapor-deposited film is obtained by using a mild sputter E1030 (manufactured by Hitachi, Ltd.) and performing a vapor deposition operation at a current value of 15 mA for 2 minutes. The sample after the vapor deposition operation is used as a measurement sample. At the time of measurement, the main electrode having a diameter of 22 mm is placed so as not to protrude from the main electrode film having a diameter of 25 mm. Further, the measurement is performed by placing a guard ring electrode having an inner diameter of 41 mm on the electrode film so as not to protrude from the guard ring electrode film having an inner diameter of 38 mm and an outer diameter of 50 mm. The measurement is performed in an environment of a temperature of 23 ° C./humidity of 55% RH. Prior to the measurement, the measurement sample is left in the environment for 24 hours or more. In the above state, the volume resistance (Ω) of the test piece is measured. Next, when the measured volume resistance value is RM (Ω) and the thickness of the test piece is t (cm), the volume resistivity RR (Ω · cm) of the test piece is obtained by the following equation.

RR (Ω · cm) = π × 1.25 × 1.25 × RM (Ω) ÷ t (cm)
<Method for measuring electrical resistance of developing roller>
The apparatus used for the electrical resistance measurement is shown in FIG. The measurement environment is a temperature of 23 ° C./humidity of 55% Rh. The developing roller 6 is in contact with a metal drum 29 having a diameter of 50 mm with a load of 4.9 N applied to both ends of the conductive shaft of the developing roller. By driving the metal drum 29 at a surface speed of 50 mm / sec by driving means (not shown), the developing roller 6 is driven to rotate. A voltage of +50 V is applied from the high voltage power supply HV to the conductive shaft of the developing roller. A digital multimeter (DMM) is used to calculate a potential difference between both ends of a resistor R having a known electrical resistance (two or more digits lower than the electrical resistance of the developing roller) disposed between the metal roller 29 and the ground. (Measured using FLUKE; 189TRUE RMS MULTITIMER). Next, a current flowing through the metal roller via the developing roller is calculated from the measured potential difference and the electric resistance of the resistor. The electric resistance value of the developing roller was obtained from the current and the applied voltage. Here, in the measurement with the digital multimeter, sampling is performed for 3 seconds from 2 seconds after voltage application, and the resistance value of the developing roller is calculated using the arithmetic average value.

<Method for Measuring Contact Pressure of Toner Amount Restricting Member to Developing Roller>
A sensor sheet of a surface pressure distribution system (trade name I-SCAN, manufactured by Nitta Co., Ltd.) was installed and measured in such a manner as to be sandwiched between contact portions between a developing roller and a toner amount regulating member. The sensor sheet used was a measurement part with a width of 2 mm arranged with a gap of 3 mm.

  The contact pressure was converted from measured values obtained from 70 mm to 170 mm from the end of the resin layer of the developing roller. Specifically, the pressures obtained at the 20 measurement parts were each divided by the width (0.2 cm) of the measurement part, and the arithmetic average value of the pressures at these 20 points was defined as the contact pressure.

<Method of measuring the arithmetic average particle diameter of the hollow resin particles>
The average particle diameter of the hollow resin particles 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) manufactured by Hitachi High-Technology Corporation is used for observation and measurement.

<Measurement method for the amount of hollow resin particles adhering to the surface of the developing roller>
First, 10 mm in the longitudinal direction where the developing roller is in contact with the toner amount regulating member is arbitrarily selected. Using an adhesive tape (trade name: Scotch Mending Tape MD-12, manufactured by Sumitomo 3M), all the powder adhering to the surface of the developing roller and the surface of the toner amount regulating member is peeled off. If a large amount of powder adheres and cannot be removed at once, a new adhesive tape is prepared and the same operation is repeated to remove all the powder. The weight of the powder thus peeled is measured, and the weight of the powder adhering per unit area from the ratio of the weight and the area (10 mm × “the contact width between the developing roller and the toner amount regulating member”). Is calculated. The measurement is performed at arbitrary 5 points, and the arithmetic average value of the total 5 points is set as the value of the adhesion amount.

<Measuring method of micro compression hardness>
The micro compression hardness of the hollow resin particles in the present invention was measured with an ultra micro hardness meter ENT1100a (manufactured by Elionix) under the following conditions.

・ Load range A;
Test load: 0.001N;
-Number of divisions: 1000;
・ Step interval 10msec;
Indenter type: flat plate with a diameter of 20 μm.

  The maximum displacement (μm) was read from the obtained displacement-load diagram, and the micro compression hardness calculated by the following formula was used as the micro compression hardness of the hollow resin particles in the present invention.

Micro compression hardness of hollow resin particles = test load 0.001 (N) / maximum displacement (μm)
<Measurement method of powder circularity>
Using a flow type particle image measuring device FPIA-2100 type (manufactured by Sysmex Corporation), 1000 or more powders were measured, and the circularity of each of the measured powders was determined by the following formula (1).

Circularity a = L0 / L (1)
[In the formula, L0 indicates the circumference of a circle having the same projected area as the powder image, and L is the powder when image processing is performed at an image processing resolution of 512 × 512 (0.3 μm × 0.3 μm pixels). Indicates the perimeter of the image. ]
EXAMPLES Hereinafter, although this invention is demonstrated in detail using an Example and a comparative example, a present Example does not limit this invention at all.

(Production roller development)
[Preparation of developing roller 1]
"Formation of elastic layer"
A primer (trade name DY35-051, manufactured by Toray Dow Corning Silicone Co., Ltd.) was applied and baked on a conductive shaft 1 made of SUS304 and having a diameter of 8 mm. Next, the conductive shaft 1 was placed concentrically in a cylindrical mold having an inner diameter of 16 mm, and a liquid silicone rubber composition having the following composition was injected.

(Formulation of liquid silicone rubber composition)
-100 parts by mass of liquid silicone rubber material (trade name SE6724A / B, manufactured by Toray Dow Corning Silicone)-35 parts by mass of carbon black talker black (trade name # 7360SB, manufactured by Tokai Carbon Co., Ltd.) "TOKABLACK" is a registered trademark)
-0.2 part by mass of silica powder-0.1 part by mass of platinum catalyst Subsequently, the mold was heated to cure and cure the silicone rubber at a temperature of 150 ° C for 15 minutes, and after demolding, the temperature was further 200 ° C The curing reaction was completed by heating for 2 hours, and an elastic layer 2 having a thickness of 4 mm was provided on the outer periphery of the conductive shaft body 1.

"Synthesis of polyols"
To 100 parts by mass of polytetramethylene glycol (trade name PTG1000SN, manufactured by Hodogaya Chemical Co., Ltd.), 20 parts by mass of an isocyanate compound (trade name Millionate MT, manufactured by Nippon Polyurethane Industry Co., Ltd.) were mixed stepwise in a methyl ethyl ketone (MEK) solvent. . The mixed solution was reacted at a temperature of 80 ° C. for 7 hours under a nitrogen atmosphere to prepare a polyether polyol having a hydroxyl value of 20 mgKOH / g. ("Millionate \ MILLIONATE" is a registered trademark)
"Synthesis of isocyanate"
In a nitrogen atmosphere, 57 parts by mass of crude MDI (trade name Cosmonate M-200, manufactured by Mitsui Chemicals Polyurethanes Co., Ltd.) is heated to 90 ° C. with respect to 100 parts by mass of polypropylene glycol (trade name Excenol, manufactured by Asahi Glass Co., Ltd.) having a number average molecular weight of 400. And reacted for 2 hours. Thereafter, butyl cellosolve was added so as to have a solid content of 70%, and an isocyanate compound having a mass ratio of NCO groups contained per unit solid mass of 5.0% by mass was obtained. Thereafter, 22 parts by mass of MEK oxime was added dropwise under a reaction temperature of 50 ° C. to obtain block polyisocyanate A. ("Cosmonate \ COSMONATE" is a registered trademark)
"Preparation of paint for resin layer"
100 parts by mass of the polyol and 33.4 parts by mass of the block polyisocyanate A are mixed, and 30 parts by mass of carbon black (trade name MA100, manufactured by Mitsubishi Chemical Corporation, pH = 3.5) with respect to 100 parts by mass of the mixed liquid. Parts were added. Next, MEK was added and mixed so that the solid content was 35% by mass, and dispersion was performed using a glass bead having a particle diameter of 1.5 mm for 4 hours with a sand mill. Then, 38 parts by mass of PMMA particles (trade name: MX-1000; Sφ10 μm; manufactured by Soken Chemical Co., Ltd.) was added to MEK having the same mass as the solid content in the dispersion, and dispersion 2 was obtained by ultrasonic dispersion. Got. The obtained dispersion liquid 2 was added to the dispersion liquid 1, and further dispersed for 30 minutes using a sand mill to obtain a coating material for a resin layer.

"Formation of resin layer on elastic layer"
The coating material for the resin layer is dip-coated on the elastic layer using an overflow-type dip coating apparatus shown in FIG. 4, and then dried at room temperature and heat-treated at a temperature of 150 ° C. for 2 hours. Thus, the developing roller 1 was obtained.

[Preparation of developing roller 2]
It was produced in the same manner as the developing roller 1 except that the number of added PMMA particles was changed to 5 parts by mass.

[Preparation of developing roller 3]
It was produced in the same manner as the developing roller 1 except that the number of added PMMA particles was changed to 15 parts by mass.

[Preparation of developing roller 4]
It was produced in the same manner as the developing roller 1 except that the number of added PMMA particles was changed to 75 parts by mass.

[Preparation of developing roller 5]
It was produced in the same manner as the developing roller 1 except that the number of added PMMA particles was changed to 95 parts by mass.

[Method of adhering hollow resin particles to developing roller 1]
As an adhesion method, for example, a method in which an appropriate amount of hollow resin particles is poured into a funnel little by little, and the funnel is tilted moderately while being reciprocated in the longitudinal direction at a certain height from the rotating developing roller. There is. Further, the amount of hollow resin particles attached can be controlled by the rotation speed and time of the developing roller. In addition, the adhesion method of the hollow resin particle in this invention should just be able to adhere uniformly on a developing roller, and is not restricted to this method.

<Example 1>
[Image output test]
A developing roller 1 having a hollow resin particle (trade name: EXPANCEL 920DE40d30, manufactured by Nippon Philite Co., Ltd.) attached to the entire surface with an adhesion amount of 1.2 × 10 ⁻⁸ mg / cm ² by the above method is applied to a laser printer (product Name: LBP5500). The hollow resin particles had a micro compression hardness of 1.1 × 10 ⁻⁴ N / μm. The cartridge is modified as follows. “Expansel” and “LBP” are registered trademarks)
Remodeling point 1: The toner amount regulating member was changed to a metal plate made of SUS304 having a thickness of 80 μm. A blade bias can be applied to the member.

  Remodeling point 2: A non-magnetic one-component magenta toner having a weight average particle diameter of 6.5 μm and a circularity of 0.97 produced by the polymerization method described in Example 1 of JP-A-2006-106198 was filled.

  The contact pressure of the toner amount regulating member against the developing roller was adjusted to 20 g / cm, and left for 60 days in an environment of temperature 40 ° C. and humidity 95% RH. After completion of leaving under high temperature and high humidity, the process cartridge was left in an environment of a temperature of 23 ° C. and a humidity of 55% RH for 1 day. After that, it was loaded into a Canon printer LBP5500 remodeled machine (modified so that a blade bias can be applied to the toner amount regulating member), and image evaluation was performed as follows. Here, a blade bias of −200 V with respect to the developing bias was applied to the toner amount regulating member 9.

  One halftone image was output at a speed of 17 sheets / minute in an environment of a temperature of 23 ° C. and a humidity of 55% RH, and the images were evaluated according to the following criteria. The results are shown in Table 1.

<Image Evaluation 1: Evaluation of Belt-like Image Defect Caused by Plastic Deformation of Developing Roller>
A: A belt-like image defect due to plastic deformation of the developing roller is not visually observed.

  B: Although a belt-like image defect due to plastic deformation of the developing roller is extremely slight, there is no problem in terms of image.

  C: A belt-like image defect due to plastic deformation of the developing roller is observed.

<Image evaluation 2: Evaluation of streak-like image defects caused by remaining hollow resin particles on the developing roller>
A: Visually, no streak-like image defect due to particles remaining on the developing roller is observed.

  B: Although a streak-like image defect caused by particles remaining on the developing roller is extremely slight, there is no problem in image.

  C: A streak-like image defect due to particles remaining on the developing roller is observed.

<Example 2>
Evaluation was performed in the same manner as in Example 1 except that the hollow resin particles in Example 1 were changed to (trade name: EXPANCEL 551DE40D42; manufactured by Nippon Philite Co., Ltd.). The results are shown in Table 1.

<Example 3>
Evaluation was performed in the same manner as in Example 1 except that the hollow resin particles in Example 1 were changed to (trade name: EXPANCEL 092DE120d30; manufactured by Nippon Philite Co., Ltd.). The results are shown in Table 1.

<Example 4>
Evaluation was performed in the same manner as in Example 1 except that the hollow resin particles in Example 1 were changed to (trade name: Microsphere-F-100; manufactured by Matsumoto Yushi Seiyaku Co., Ltd.). The results are shown in Table 1.

<Example 5>
Evaluation was performed in the same manner as in Example 1 except that the hollow resin particles in Example 1 were changed to (trade name: Microsphere-F-2; manufactured by Matsumoto Yushi Seiyaku Co., Ltd.). The results are shown in Table 1.

<Example 6>
Evaluation was performed in the same manner as in Example 1 except that the amount of the hollow resin particles attached was changed to 5.0 × 10 ⁻⁹ . The results are shown in Table 1.

<Example 7>
Evaluation was performed in the same manner as in Example 1 except that the adhesion amount of the hollow resin particles was changed to 4.0 × 10 ⁻⁸ . The results are shown in Table 1.

<Example 8>
Evaluation was performed in the same manner as in Example 2 except that the amount of the hollow resin particles attached was changed to 5.0 × 10 ⁻⁹ . The results are shown in Table 1.

<Example 9>
Evaluation was performed in the same manner as in Example 2 except that the amount of the hollow resin particles attached was changed to 4.0 × 10 ⁻⁸ . The results are shown in Table 1.

<Example 10>
Evaluation was performed in the same manner as in Example 3 except that the amount of the hollow resin particles attached was changed to 5.0 × 10 ⁻⁹ . The results are shown in Table 1.

<Example 11>
Evaluation was performed in the same manner as in Example 3 except that the amount of the hollow resin particles attached was changed to 4.0 × 10 ⁻⁸ . The results are shown in Table 1.

<Example 12>
Evaluation was performed in the same manner as in Example 4 except that the amount of the hollow resin particles attached was changed to 3.2 × 10 ⁻⁹ . The results are shown in Table 1.

<Example 13>
Evaluation was performed in the same manner as in Example 4 except that the adhesion amount of the hollow resin particles was changed to 5.1 × 10 ⁻⁸ . The results are shown in Table 1.

<Example 14>
Evaluation was performed in the same manner as in Example 5 except that the adhesion amount of the hollow resin particles was changed to 3.0 × 10 ⁻⁹ . The results are shown in Table 1.

<Example 15>
Evaluation was performed in the same manner as in Example 5 except that the adhesion amount of the hollow resin particles was changed to 5.0 × 10 ⁻⁸ . The results are shown in Table 1.

<Example 16>
Evaluation was performed in the same manner as in Example 4 except that the attached amount of the hollow resin particles was changed to 5.0 × 10 ⁻⁹ . The results are shown in Table 1.

<Example 17>
Evaluation was performed in the same manner as in Example 2 except that the amount of the hollow resin particles adhered was changed to 3.2 × 10 ⁻⁹ . The results are shown in Table 1.

<Example 18>
Evaluation was performed in the same manner as in Example 3 except that the amount of the hollow resin particles attached was changed to 3.2 × 10 ⁻⁹ . The results are shown in Table 1.

<Example 19>
Evaluation was performed in the same manner as in Example 5 except that the adhesion amount of the hollow resin particles was changed to 5.0 × 10 ⁻⁹ . The results are shown in Table 1.

<Example 20>
Evaluation was performed in the same manner as in Example 4 except that the amount of the hollow resin particles attached was changed to 4.0 × 10 ⁻⁸ . The results are shown in Table 1.

<Example 21>
Evaluation was performed in the same manner as in Example 2 except that the adhesion amount of the hollow resin particles was changed to 5.1 × 10 ⁻⁸ . The results are shown in Table 1.

<Example 22>
Evaluation was performed in the same manner as in Example 5 except that the amount of the hollow resin particles attached was changed to 4.0 × 10 ⁻⁸ . The results are shown in Table 1.

<Example 23>
Evaluation was performed in the same manner as in Example 3 except that the amount of the hollow resin particles attached was changed to 5.1 × 10 ⁻⁸ . The results are shown in Table 1.

<Examples 24-27>
Evaluation was performed in the same manner as in Example 1 except that the developing roller was changed as shown in Table 1. The results are shown in Table 1.

<Comparative Example 1>
A developing roller of Comparative Example 1 was obtained in the same manner as in Example 1 except that the hollow resin particles were changed to acrylic resin particles (trade name: MBX20X-5; manufactured by Sekisui Chemical Co., Ltd.). The results are shown in Table 1.

<Comparative Example 2>
A developing roller of Comparative Example 2 was obtained in the same manner as in Example 1 except that the hollow resin particles were changed to hollow glass particles (trade name: Q-CEL 520FPS; manufactured by Potters Barotini). The results are shown in Table 1.

<Comparative Example 3>
Evaluation was performed in the same manner as in Example 1 without attaching the hollow resin particles to the surface of the developing roller. The results are shown in Table 1.

DESCRIPTION OF SYMBOLS 1 Conductive shaft body 2 Elastic layer 3 Resin layer 4 Electrophotographic process cartridge 5 Photosensitive drum 6 Developing roller 7 Toner coating member 8 Toner 9 Toner amount regulating member 10 Developing device 11 Laser beam 12 Charging member

Claims (3)

An electrophotographic process cartridge comprising a developing roller having an elastic layer, and a toner amount regulating member for forming a toner layer on the surface of the developing roller,
The developing roller has hollow resin particles attached to the surface thereof, the developing roller and the toner amount regulating member are in contact with each other through the hollow resin particles, and
The process cartridge for electrophotography, wherein the hollow resin particles fall off from the surface by rotating a developing roller. 2. The electrophotographic process cartridge according to claim 1, wherein the hollow resin particles have a micro compression hardness of 0.6 × 10 ⁻⁴ N / μm or more and 1.5 × 10 ⁻⁴ N / μm or less. ^{3. The} hollow resin particles are attached to the surface of the developing roller at a density of 5 × 10 ⁻⁹ mg / cm ² or more and 4 × 10 ⁻⁸ mg / cm ² or less. Process cartridge for electrophotography.

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