JP2009042580A - Single-component developing device, process cartridge and image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a single-component developing device suppressing uneven image density due to insufficient resetting property of toner and obtaining excellent image stability. <P>SOLUTION: The single-component developing device includes at least a developing roller 103 for depositing a pulverized toner with internally added wax on an image carrier 2 where an electrostatic latent image is formed and visualizing the electrostatic latent image, and with a destaticization sheet 108 to be brought into contact with the developing roller 103 to eliminate charges held by the toner, wherein the volume resistivity R (Ω cm) of the destaticization sheet and the impedance Z (Ω) of the toner satisfy the relationship of the following expressions (1) to (3) and the frictional force between toner particles is 2.0 to 2.5 mNm. The expressions are: (1) 10<Log<SB>10</SB>R<14; (2) 8.00<Log<SB>10</SB>Z<10.70; and (3)-1.5×Log<SB>10</SB>R+23.5<Log<SB>10</SB>Z<-1.5×Log<SB>10</SB>R+31.0. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a one-component developing device, and in particular, after a toner thin layer is formed by pressing a developing roller and a regulating blade, an electrostatic latent image is developed using the toner thin layer, and then on the developing roller. The present invention relates to a one-component developing device that neutralizes remaining toner with a neutralizing sheet.

Conventionally, in electrophotography, the electrostatic latent image formed by charging and exposing the surface of a photoreceptor is developed with a colored toner to form a toner image, and the toner image is transferred to a transfer medium such as transfer paper. This is fixed with a heat roll or the like to form an image.
Dry development methods employed in electrophotography, electrostatic recording, and the like include a method using a two-component developer composed of a toner and a carrier, and a method using a one-component developer not containing a carrier. The former method provides a relatively stable and good image, but it is difficult to obtain a constant quality image over a long period of time because carrier deterioration and a change in the mixing ratio of toner and carrier are likely to occur. In addition, there are difficulties in maintaining and managing the apparatus and making it compact. Therefore, the latter method using a one-component developer that does not have such drawbacks has been attracting attention.

  By the way, in this system, means for visualizing the electrostatic latent image formed on the latent image carrier by the toner (developer) usually conveyed by at least one toner conveying member and the conveyed toner. In this case, a means for regulating the toner layer thickness is opposed to the toner conveying member, and the toner is charged when the toner passes through the regulating means. Various methods have been proposed for the toner layer thickness regulating means (toner layer thickness regulating means) placed on the toner conveying member. As a typical example, a regulating blade is used, and this blade is opposed to the toner conveying member. Thus, the toner conveyed on the surface of the toner conveying member is pressed by a pressing member (regulating blade) to control the toner layer thickness. There is also a type that obtains the same effect by contacting a roller instead of a blade.

In this one-component development method, the toner on the developing roller that has not been used in the developing area is scraped by the supply roller and guided again into the toner hopper. However, when the adhesion force between the toner particles and the developing roller is large, the scraping property, that is, the resetting property is deteriorated, and the toner rolls around the developing roller many times. As a result, the toner adhesion amount on the developing roller increases and stable charging / conveyance cannot be performed.
In order to solve such problems, various improvements have been made to reduce the adhesion between the developing roller and the toner as described later.

For example, in the developing device described in Patent Document 1 (Japanese Patent No. 3502554), the resistance of the static elimination sheet material, the static elimination nip, the relative dielectric constant, and the volume resistivity are defined.
The developing device described in Patent Document 2 (Japanese Patent Laid-Open No. 9-134100) uses a loop-shaped static elimination sheet with a resistance of 1 × 10 ³ to 1 × 10 ⁸ Ω.
The developing device described in Patent Document 3 (Japanese Patent Laid-Open No. 2005-75505) has a charge eliminating sheet resistivity of 1 to 1 × 10 ⁵ Ω · cm.
However, the methods described in Patent Documents 1 to 3 cannot achieve a good balance between charging and resetting.
Japanese Patent No. 3502554 Japanese Patent Laid-Open No. 9-134100 JP-A-2005-75505

  SUMMARY OF THE INVENTION An object of the present invention is to provide a one-component developing device that suppresses uneven image density due to poor resetability of toner and that provides excellent image stability.

As a result of intensive studies on the above problems, the inventors of the present invention are able to achieve a good balance between charging and resetting by defining the relationship between the volume resistance of the static elimination sheet and the toner impedance and the frictional force between the toner particles. As a result, the inventors have found that the above-mentioned problems can be solved, and have reached the present invention.
That is, the present invention is as follows.
(1) At least an image bearing member on which an electrostatic latent image is formed is made to adhere pulverized toner with wax, and the electrostatic latent image is visualized and brought into contact with the developing roller to remove the charge held by the toner. In a one-component developing apparatus having a charge eliminating sheet, the volume resistance R (Ω · cm) of the charge eliminating sheet and the impedance Z (Ω) of the toner satisfy the relationship of the following formulas (1) to (3), and the friction between the toner particles A one-component developing device having a force of 2.0 to 2.5 mNm.
Formula (1) 10 <Log ₁₀ R <14
Formula (2) 8.00 <Log ₁₀ Z <10.70
Formula (3) −1.5 × Log ₁₀ R + 23.5 <Log ₁₀ Z <−1.5 × Log ₁₀ R + 31.0

(2) One-component development according to (1), wherein the toner has a wax content of 3.0 to 7.0% by mass and is used in an image forming apparatus having a fixing system that does not use oil. apparatus.
(3) One-component development as described in (1) or (2) above, wherein the toner has an average circularity of 0.900 to 0.930 and a volume average particle diameter of 6 to 10 μm. apparatus.
(4) The one-component developing device according to any one of (1) to (3), wherein a space ratio obtained from a displacement when a load is applied to the toner is 56 to 58%.
(5) A process cartridge comprising at least the one-component developing device according to any one of (1) to (4).
(6) An image forming apparatus comprising at least the one-component developing device according to any one of (1) to (4).

  At least an image bearing member on which an electrostatic latent image is formed is attached with a pulverized toner containing wax, and a developing roller for visualizing the electrostatic latent image, and a discharging sheet for discharging the charge held by the toner by contacting the developing roller. In the one-component developing device, the relationship between the volume resistance R of the charge eliminating sheet and the impedance Z of the toner and the frictional force between the toner particles can be defined, so that the balance between the charge and the reset can be well achieved, and the toner resetability is poor. Therefore, it is possible to provide a one-component developing device that suppresses image density unevenness due to the above-described characteristics and that provides excellent image stability.

In the one-component developing device of the present invention, at least an image bearing member on which an electrostatic latent image is formed is adhered to a developing roller for visualizing the electrostatic latent image by attaching wax-added pulverized toner and the toner is held by the developing roller. In a one-component developing device including a static elimination sheet that neutralizes the charge to be discharged, the volume resistance R (Ω · cm) of the static elimination sheet and the impedance Z (Ω) of the toner satisfy the relationship of the following formulas (1) to (3): In addition, the one-component developing device is characterized in that the frictional force between toner particles is 2.0 to 2.5 mNm.
Here, the electrical characteristics of the toner are measured by alternating current because electrical characteristics close to actual actual machine behavior can be obtained. The toner is considered to exchange electric charges by rotating in the actual machine or coming into contact with various parts. Therefore, it is considered that the impedance measurement by alternating current can obtain the electrical characteristics closer to the actual machine behavior.
Formula (1) 10 <Log ₁₀ R <14
Formula (2) 8.00 <Log ₁₀ Z <10.70
Formula (3) −1.5 × Log ₁₀ R + 23.5 <Log ₁₀ Z <−1.5 × Log ₁₀ R + 31.0

When Log ₁₀ R is smaller than 10, the volumetric resistance of the charge removal sheet is low, so the charge removal amount of the toner is increased, and the amount of toner having no charge is increased, so that the toner scattering amount is increased. On the other hand, if the value is larger than 14, the volume resistance of the charge removal sheet is too high, so that the charge of the toner cannot be discharged efficiently, and the toner resetability is lowered.
If Log ₁₀ Z is less than 8.00, the toner impedance is low, so the toner charge amount is low and the charge removal amount is large. As a result, the amount of toner having no charge increases, so the amount of toner scattering increases. On the other hand, if it is greater than 10.70, the toner impedance is high, the toner charge amount is high, and it is difficult to remove the charge, so the toner reset property on the developing roller is lowered.
Further, when Log ₁₀ Z is smaller than −1.5 × Log ₁₀ R + 23.5, the toner charge amount is low and the charge removal amount is large. As a result, the amount of toner having no charge increases, so the amount of toner scattering increases. On the other hand, if it is larger than −1.5 × Log ₁₀ R + 31.0, the toner impedance is high, so the charge of the toner cannot be removed efficiently, and the toner resetting property is lowered.
The impedance of the toner can be adjusted by, for example, the amount of charge control agent added. As the amount of the charge control agent increases, the toner impedance tends to decrease. Further, the impedance changes by changing the dispersion diameter of the charge control agent, etc., and there is a tendency of high dispersion and high impedance.

In the present invention, the toner impedance was measured as follows.
The toner impedance was measured in a state where a pellet obtained by pressurizing 3.0 g of toner at 6 MPa for 30 seconds was put into a liquid cell (12964A type liquid measuring cell manufactured by Toyo Technica Co., Ltd.) and pressurized with 7.5 N. The measurement was performed by changing the voltage to 0.1 V and the frequency from 100 Hz to 10000 Hz, and fitting the resistance component and capacitance component data for each frequency to calculate the resistance component R2.
Analysis can be performed using commercially available software. In this example, Zlot sold by Toyo Technica was used, and the equivalent circuit shown in FIG. 2 was specified and analyzed.
FIG. 2 shows an equivalent circuit, where R1 and R2 are resistance components, and C1 is a capacitance component.

If the frictional force between the toner particles is less than 2.0 mNm, the toner particles easily pass through the neutralization nip, so that it is difficult to eliminate the charge uniformly. Moreover, since it will become easy to be trapped by the static elimination nip when it becomes larger than 2.5 mNm, it is easy to become static elimination sheet adhering.
The toner particle frictional force can be adjusted by the amount of the external additive and the processing conditions. When the particle size of the external additive is large, the frictional force between the toner particles increases, and when the amount of the external additive is small, the frictional force between the toner particles increases.

FIG. 3 shows an example of an evaluation apparatus used for measuring the frictional force between toner particles in the present invention. This evaluation apparatus is composed of a consolidation zone and a measurement zone. After pressurizing the toner in the consolidation zone, the torque and load are measured in the measurement zone to determine the frictional force between the toner particles.
The consolidation zone is composed of a container 216 for storing powder, an elevating stage 218 for moving the container up and down, a piston 215 for consolidation, a weight 214 for applying a load to the piston, and the like.
In this configuration example, the sample container 216 containing the powder is raised, brought into contact with the compacting piston 215, and further lifted to lift the weight 214 from the support plate 219 so that all the load of the weight 214 is applied to the piston 215. Leave it for a certain period of time. Thereafter, the lifting / lowering stage 218 on which the powder container 216 is placed is lowered, and the piston 215 is separated from the powder surface.

The piston 215 may be made of any material, but it needs to have a smooth surface on which the powder is pressed. Therefore, a material that is easy to process, has a hard surface, and does not change quality is preferable. Further, it is necessary to prevent the powder from adhering due to charging, and a conductive material is suitable. Examples of this material include SUS, Al, Cu, Au, Ag, and brass.
In the present invention, the powder container 216 has an inner diameter of 60 mm, and the height of the compacted powder is 25 to 28 mm.

As shown in FIG. 3, the measurement zone includes a container 216 for storing powder, an elevating stage 218 for moving the container up and down, a load cell 213 for measuring the load, a torque meter 211 for measuring the torque of the powder, and the like. Composed. In addition, this structure is an example and does not limit this invention.
The conical rotor 212 is attached to the tip of the shaft, and the shaft itself is fixed so as not to move in the vertical direction.
The sample container stage containing the powder can be moved up and down by an elevator, the container 216 containing the powder is placed in the center of the stage, and the conical rotor 212 is rotated at the center of the container by raising the container. While trying to invade.
Torque applied to the conical rotor 212 is detected by a torque meter 211 at the top, and a load applied to the container 216 containing powder is detected by a load cell 213 below the container. Perform with a detector.
This configuration is an example, and other configurations that can move the shaft itself up and down by an elevator are also applicable.

FIG. 4 is a diagram of a conical rotor used for measuring the frictional force between toner particles in the present invention. The shape of the conical rotor 212 is such that the apex angle of the cone is 60 ° and the surface is grooved as shown in FIG. A groove is cut straight from the apex of the cone in the direction of the base, and the cross section of the groove has a sawtooth shape consisting of triangular irregularities. The length of the side of the conical rotor is 30 mm, the depth of the groove at the apex is 0 mm, the depth of the groove at the bottom surface portion is 1 mm, and the groove gradually becomes deeper. The number of grooves is 48.
Rather than measuring the friction component between the material surface of the conical rotor 212 and the toner particles, the friction component between the toner particles and the toner particles is measured.

Contact between the material surface of the conical rotor 212 and the toner particles is only at the tip of the crest of the triangular groove. Most of the contact is between the toner particles that have entered the groove and the surrounding toner particles.
The material of the conical rotor 212 is not particularly limited, and a material that is easy to process, has a hard surface, and does not change in quality is preferable, and a material that does not have charging property is suitable. Specific examples include SUS, Al, Cu, Au, Ag, brass, and the like.

The fluidity of the toner powder of the toner is evaluated by allowing the conical rotor to enter the powder phase while rotating, and measuring the torque or load generated when the conical rotor moves in the powder phase. Specifically, while rotating the conical rotor into the toner powder phase, the conical rotor is allowed to enter (lower) or withdraw (up), and the torque applied to the container containing the conical rotor and the toner powder phase at that time The load is measured, and the fluidity is evaluated by the torque and load value. When the frictional force between toner particles is μ, the powder stress is σ, and the penetration depth of the conical rotor is h, the rotational torque T is T = μ · σ · h ³ · m
(M is a constant)
From this equation, the frictional force μ between the toner particles can be obtained.
The torque and load of the toner powder vary depending on the rotational speed of the conical rotor, that is, the rotational speed per minute (hereinafter, abbreviated as the rotational speed; the unit is rpm) and the conical rotor intrusion speed. Therefore, in order to increase the measurement accuracy, the rotation speed and the intrusion speed of the conical rotor 212 are decreased so that the delicate contact state between the toner particles can be measured. Therefore, the measurement conditions were as follows.
Number of rotations of conical rotor: 0.1 to 100 rpm
Conical rotor penetration speed: 0.5 to 150 mm / min
In the present invention, the measurement was performed under the following conditions.
・ Rotation speed of conical rotor 1.0rpm
・ Intrusion speed of conical rotor 1.0mm / min
・ Pressurization of toner layer Pressurization for over 60 seconds at 0.1 kg / cm ² or more ・ Conical rotor shape The apex angle of the cone is 60 °
-Conical rotor entry depth 20mm

  The amount of wax in the toner is preferably 3.0 to 7.0% by mass. If it is less than 3.0% by mass, it cannot be used in an oilless fixing system. If it is larger than 7.0% by mass, the wax dispersion diameter becomes large and sticking is likely to occur, making it difficult to use in a one-component development system.

  The toner volume average particle diameter is preferably 6 to 10 μm, and the average circularity is preferably 0.900 to 0.930. When the toner volume average particle diameter is smaller than 6 μm, the adhesion of the toner particles itself is remarkably increased, so that the toner resetting property is greatly lowered. If it is larger than 10 μm, there is no problem in terms of static elimination, but the halftone texture is remarkably lowered, so that the product is not realized. If the average circularity is less than 0.900, it is likely to be trapped in the neutralization nip, and hence the neutralization sheet is likely to be fixed. Furthermore, the halftone texture is significantly reduced. Toners greater than 0.930 are difficult to manufacture with oilless ground toner.

  A method for measuring the particle size distribution of the toner particles will be described. Examples of the measuring device for the particle size distribution of toner particles by the Coulter counter method include Coulter Counter TA-II and Coulter Multisizer II (both manufactured by Coulter). The measurement method is described below. First, 0.1 to 5 ml of a surfactant (preferably alkylbenzene sulfonate) is added as a dispersant to 100 to 150 ml of an aqueous electrolytic solution. Here, the electrolytic solution is a solution prepared by preparing a 1% NaCl aqueous solution using primary sodium chloride. For example, ISOTON-II (manufactured by Coulter) can be used. Here, 2 to 20 mg of the measurement sample is further added as a solid content. The electrolytic solution in which the sample is suspended is subjected to a dispersion treatment with an ultrasonic disperser for about 1 to 3 minutes, and the measurement device is used to measure the volume and number of toner particles or toner using a 100 μm aperture as an aperture. Volume distribution and number distribution are calculated. From the obtained distribution, the weight average particle diameter (Dv) and the number average particle diameter (Dp) of the toner can be obtained. As channels, 2.00 to less than 2.52 μm; 2.52 to less than 3.17 μm; 3.17 to less than 4.00 μm; 4.00 to less than 5.04 μm; 5.04 to less than 6.35 μm; 6 Less than 35 to 8.00 μm; less than 8.00 to less than 10.08 μm; less than 10.08 to less than 12.70 μm; less than 12.70 to less than 16.00 μm; less than 16.00 to less than 20.20 μm; Uses 13 channels of less than 40 μm; 25.40 to less than 32.00 μm; 32.00 to less than 40.30 μm, and targets particles having a particle size of 2.00 μm to less than 40.30 μm.

  As a method for measuring the shape of the toner, an optical detection band method is suitable in which a suspension containing particles is passed through an imaging unit detection band on a flat plate, and a particle image is optically detected and analyzed by a CCD camera. . A toner having an average circularity of 0.890 or more, which is a value obtained by dividing the perimeter of an equivalent circle having the same projected area obtained by this method by the perimeter of the actual particle, is a high-definition image having a reproducibility with an appropriate density. It was found to be effective in forming. More preferably, the average circularity is 0.900 to 0.930. This value is a value measured as an average circularity by a flow type particle image analyzer FPIA-2000. As a specific measuring method, 0.1 to 0.5 ml of a surfactant, preferably alkylbenzene sulfonate is added as a dispersant to 100 to 150 ml of water from which impure solids have been removed in advance, and further measurement is performed. Add about 0.1-0.5g of sample. The suspension in which the sample is dispersed is obtained by performing dispersion treatment for about 1 to 3 minutes with an ultrasonic disperser and measuring the shape and distribution of the toner with the above apparatus at a dispersion concentration of 3000 to 10,000 / μl. .

The space ratio of the toner powder layer is also important. The space ratio is obtained from the following formula.
ε = (V−M / ρ) / V
(Where ε is the void ratio, M is the mass of the toner powder filled in the measurement container, ρ is the true specific gravity of the toner powder, and V is the volume of the toner layer.)
The volume of the toner layer can be obtained by applying a load of 66 g / cm ² from the upper surface of the container containing the toner powder and then measuring the height of the toner layer using a laser displacement meter.
Usually, the toner is used by appropriately mixing not only toner particles but also inorganic organic additives such as silica and titanium oxide. In addition to the above-described characteristics of the base toner, the cleaning characteristics can be further stabilized by adjusting the characteristics after mixing the additives.

  A higher space ratio is better. As a result of examination, if the space ratio is 50% or more, good cleaning properties are easily obtained. Although the relationship between the space ratio and the cleaning property is not clear, the lower the space ratio, the higher the density of toner accumulated at the tip of the cleaning blade, and it seems that the cleaning blade is pushed up and easily slips through. When the space ratio exceeds 60%, the image forming apparatus is liable to float and the inside of the image forming apparatus may be stained due to toner scattering. The space ratio can be adjusted by the particle diameter of the external additive and the adhesion strength of the external additive. When the particle size of the external additive is increased, the space ratio is increased, and when the adhesion state of the external additive is increased, the space ratio is increased.

The adhesion strength of the external additive can be measured as follows, and the higher this value, the higher the adhesion strength.
After 2 g of toner was added to 30 cc of a surfactant solution diluted 10 times and thoroughly blended, energy was applied at 40 W for 1 minute using an ultrasonic homogenizer to separate, wash and dry the toner, It is obtained by calculating the ratio of the adhesion amount of inorganic particles before and after treatment using a fluorescent X-ray analyzer. The fluorescent X-ray analysis was performed by applying a force of 1 N / cm ^{2 to 2} g of each of the dry toner obtained by the above treatment and the untreated toner using a wavelength dispersive X-ray fluorescence analyzer XRF1700 manufactured by Shimadzu Corporation for 60 seconds. A pellet is prepared and an element unique to inorganic fine particles (for example, silicon in the case of silica) is quantified by a calibration curve method.

  In the present invention, toner having a space ratio of 50 to 60% in the toner recovery device, and when the conical rotor enters 20 mm by the above torque measurement method, the frictional force between the toner particles is 2.0 to 2. If it is in the range of 5 mNm, good cleaning properties are exhibited. The reason for this is not clear, but in the operation state of the cleaning blade, the toner stays in the vicinity of the contact portion between the blade and the photoconductor, and when the toner comes in contact with the newly carried toner on the photoconductor, If the frictional force is strong, the toner is considered to be easily peeled off from the photoreceptor. If the frictional force between the toner particles is less than 2.0 mNm, the toner cohesive force is small, so that the toner particles are likely to float and may contaminate the image forming apparatus. If the frictional force between the toner particles exceeds 2.5 mNm, the toner cohesive force increases, making it difficult to clean, and an abnormal image such as the previous image remaining may occur.

The space ratio is preferably 56 to 58%. If the space ratio is less than 56%, the movement as the toner particles is very smooth, so that there are cases where the charge removal cannot be performed well at the charge removal nip.
If it is larger than 58%, the movement as toner particles is not smooth, so that it tends to be trapped in the neutralization nip, and the neutralization sheet is likely to be fixed.

  For the above reasons, the electrostatic latent image is developed using a thin toner layer formed after passing through the regulating means, and then the toner remaining on the developing roller is neutralized by the neutralizing sheet and then reset by the supply roller. In order to stabilize the toner conveyance amount and, as a result, to stabilize the toner charge amount, there are areas with good impedance, volumetric resistance of the neutralization sheet, and frictional force between the toner particles, and it is important to be within the scope of the present invention. is there.

  The toner base that can be used in the present invention usually contains a binder resin, a colorant, and other additives. In this toner base material, a colorant, a charge control agent, a release agent, and the like are melt-mixed in a thermoplastic resin as a binder resin component and uniformly dispersed to obtain a composition, which is then pulverized. A toner base obtained by classification can be used.

(Binder resin)
The type of binder resin is not particularly limited, and binder resins known in the field of full-color toners such as polyester resins, (meth) acrylic resins, styrene- (meth) acrylic copolymer resins, epoxy resins, COC (Cyclic olefin resin (for example, TOPAS-COC (manufactured by Ticona))) or the like, but from the viewpoint of stress resistance in the developing device, it is preferable to use a polyester resin.

  As the polyester resin preferably used in the present invention, a polyester resin obtained by polycondensation of a polyhydric alcohol component and a polyvalent carboxylic acid component can be used. Among the polyhydric alcohol components, examples of the dihydric alcohol component include polyoxypropylene (2,2) -2,2-bis (4-hydroxyphenyl) propane, polyoxypropylene (3,3) -2,2- Bis (4-hydroxyphenyl) propane, polyoxypropylene (6) -2,2-bis (4-hydroxyphenyl) propane, polyoxyethylene (2,0) -2,2-bis (4-hydroxyphenyl) propane Bisphenol A alkylene oxide adducts such as ethylene glycol, diethylene glycol, triethylene glycol, 1,2-propylene glycol, 1,3-propylene glycol, 1,4-butanediol, neopentyl glycol, 1,4-butenediol, 1,5-pentanediol, 1,6-hexanedio , 1,4-cyclohexanedimethanol, dipropylene glycol, polyethylene glycol, polytetramethylene glycol, bisphenol A, hydrogenated bisphenol A, and the like. Examples of the trivalent or higher alcohol component include sorbitol, 1,2,3,6-hexanetetrol, 1,4-sorbitan, pentaerythritol, dipentaerythritol, tripentaerythritol, 1,2,4-butanetriol. 1,2,5-pentanetriol, glycerol, 2-methylpropanetriol, 2-methyl-1,2,4-butanetriol, trimethylolethane, trimethylolpropane, 1,3,5-trihydroxymethylbenzene, etc. Is mentioned.

  Among the polyvalent carboxylic acid components, examples of the divalent carboxylic acid component include maleic acid, fumaric acid, citraconic acid, itaconic acid, glutaconic acid, phthalic acid, isophthalic acid, terephthalic acid, cyclohexanedicarboxylic acid, and succinic acid. , Adipic acid, sebacic acid, azelaic acid, malonic acid, n-dodecenyl succinic acid, isododecenyl succinic acid, n-dodecyl succinic acid, isododecyl succinic acid, n-octenyl succinic acid, isooctenyl succinic acid, n-octyl succinic acid , Isooctyl succinic acid, anhydrides or lower alkyl esters of these acids.

  Examples of the trivalent or higher carboxylic acid component include 1,2,4-benzenetricarboxylic acid (trimellitic acid), 1,2,5-benzenetricarboxylic acid, 2,5,7-naphthalenetricarboxylic acid, 1,2 , 4-Naphthalenetricarboxylic acid, 1,2,4-butanetricarboxylic acid, 1,2,5-hexanetricarboxylic acid, 1,3-dicarboxyl-2-methyl-2-methylenecarboxypropane, 1,2,4- Examples include cyclohexanetricarboxylic acid, tetra (methylenecarboxyl) methane, 1,2,7,8-octanetetracarboxylic acid, pyromellitic acid, empole trimer acid, anhydrides of these acids, and lower alkyl esters.

  In the present invention, as a polyester resin, a polyester resin raw material monomer, a vinyl resin raw material monomer, and a mixture of monomers that react with both resin raw material monomers are used to obtain a polyester resin in the same container. A resin obtained by performing a condensation polymerization reaction and a radical polymerization reaction for obtaining a vinyl resin in parallel (hereinafter, simply referred to as “vinyl polyester resin”) can also be suitably used. In addition, the monomer which reacts with the raw material monomers of both resins is, in other words, a monomer that can be used for both the condensation polymerization reaction and the radical polymerization reaction. That is, it is a monomer having a carboxy group that can undergo a condensation polymerization reaction and a vinyl group that can undergo a radical polymerization reaction, and examples thereof include fumaric acid, maleic acid, acrylic acid, and methacrylic acid.

  Examples of the raw material monomer for the polyester resin include the aforementioned polyhydric alcohol component and polyvalent carboxylic acid component. Examples of the raw material monomer for the vinyl resin include styrene, o-methyl styrene, m-methyl styrene, p-methyl styrene, α-methyl styrene, p-ethyl styrene, 2,4-dimethyl styrene, p-tert- Styrene or styrene derivatives such as butylstyrene and p-chlorostyrene; ethylenically unsaturated monoolefins such as ethylene, propylene, butylene and isobutylene; methyl methacrylate, n-propyl methacrylate, isopropyl methacrylate, n-butyl methacrylate , Isobutyl methacrylate, t-butyl methacrylate, n-pentyl methacrylate, isopentyl methacrylate, neopentyl methacrylate, 3- (methyl) butyl methacrylate, hexyl methacrylate, octyl methacrylate, nonyl methacrylate, methacrylate Methacrylic acid alkyl esters such as decyl oxalate, undecyl methacrylate, dodecyl methacrylate; methyl acrylate, n-propyl acrylate, isopropyl acrylate, n-butyl acrylate, isobutyl acrylate, t-butyl acrylate, acrylic Alkyl acrylates such as n-pentyl acid, isopentyl acrylate, neopentyl acrylate, 3- (methyl) butyl acrylate, hexyl acrylate, octyl acrylate, nonyl acrylate, decyl acrylate, undecyl acrylate, and dodecyl acrylate Esters; unsaturated carboxylic acids such as acrylic acid, methacrylic acid, itaconic acid, maleic acid; acrylonitrile, maleic acid ester, itaconic acid ester, vinyl chloride, vinyl acetate, vinyl benzoate, vinyl methyl ethyl ketone And vinyl hexyl ketone, vinyl methyl ether, vinyl ethyl ether and vinyl isobutyl ether. As a polymerization initiator when polymerizing the raw material monomer of the vinyl resin, for example, 2,2′-azobis (2,4-dimethylvaleronitrile), 2,2′-azobisisobutyronitrile, 1,1 Azo or diazo polymerization initiators such as' -azobis (cyclohexane-1-carbonitrile), 2,2'-azobis-4-methoxy-2,4-dimethylvaleronitrile, benzoyl peroxide, dicumyl peroxide, And peroxide polymerization initiators such as methyl ethyl ketone peroxide, isopropyl peroxycarbonate, lauroyl peroxide, and the like.

As the binder resin, various polyester resins as described above are preferably used. Of these, from the viewpoint of further improving the separability and offset resistance as an oilless fixing toner, It is more preferable to use a two-binder resin.
More preferred first binder resins are vinyl polyester resins, particularly bisphenol A alkylene oxide adduct, terephthalic acid, trimellitic acid and succinic acid as raw material monomers for polyester resins, and styrene and butyl acrylate as raw material monomers for vinyl resins. And a vinyl-based polyester resin obtained using fumaric acid as a bireactive monomer.
A more preferable second binder resin is a polyester resin obtained by polycondensation of the above-mentioned polyhydric alcohol component and polyhydric carboxylic acid component, in particular, using a bisphenol A alkylene oxide adduct as the polyhydric alcohol component, As a polyester resin obtained using terephthalic acid and fumaric acid, or the above-mentioned vinyl-based polyester resin.

  In the present invention, it is preferable that a hydrocarbon wax is internally added during the synthesis of the first binder resin. In order to add the hydrocarbon wax to the first binder resin in advance, when the first binder resin is synthesized, the hydrocarbon wax is added to the monomer for synthesizing the first binder resin. What is necessary is just to synthesize | combine binder resin. For example, when the first binder resin is a vinyl-based polyester resin, a vinyl-based resin raw material monomer is added to the polyester resin raw-material monomer while stirring and heating the monomer while the hydrocarbon-based wax is added. A polycondensation reaction and a radical polymerization reaction may be performed by dropping.

(wax)
Generally, the lower the polarity of the wax, the better the releasability from the fixing member roller.
The wax used in the present invention is a hydrocarbon wax having a low polarity.
(Hydrocarbon wax)
The hydrocarbon wax is a wax composed of only carbon atoms and hydrogen atoms, and does not contain an ester group, an alcohol group, an amide group, or the like. Specific hydrocarbon waxes include polyolefin waxes such as polyethylene, polypropylene, copolymers of ethylene and propylene, petroleum waxes such as paraffin wax and microcrystalline wax, and synthetic waxes such as Fischer-Tropsch wax. . Among these, polyethylene wax, paraffin wax, and Fischer-Tropsch wax are preferable in the present invention, and polyethylene wax and paraffin wax are more preferable.

Melting | fusing point of wax The melting | fusing point of the wax in this invention is the endothermic peak of the wax at the time of temperature rising measured with a differential scanning calorimeter (DSC), and it is preferable to exist in the range of 70 to 90 degreeC. If it is higher than 90 ° C., the melting of the wax in the fixing process becomes insufficient, and the separation from the fixing member cannot be ensured. On the other hand, if the temperature is lower than 70 ° C., there is a problem in storage stability such that toner particles are fused in a high temperature and high humidity environment. In order to provide a sufficient margin for fixing separation at a low temperature, the melting point of the wax is more preferably from 70 ° C to 85 ° C, and further preferably from 70 ° C to 80 ° C.

The half-value width of the endothermic peak of the wax The half-value width of the wax endothermic peak at the time of temperature rise measured by a differential scanning calorimeter (DSC) is preferably 7 ° C. or less. Since the melting point of the wax in the present invention is relatively low, a wax whose endothermic peak is broad, that is, melted from a low temperature range, adversely affects the storage stability of the toner.

Content ratio of the first binder resin and the second binder resin The content ratio of the first binder resin (including the weight of the internally added wax) and the second binder resin in the toner particles is 20/80 to 45/55 by weight, preferably 30/70 to 40/60. If the amount of the first binder resin is too small, the separability and the high temperature offset resistance are deteriorated. When there is too much 1st binder resin, glossiness and heat-resistant storage property will fall.
More preferably, the softening point of the binder resin composed of the first binder resin and the second binder resin used in the above weight ratio is 100 to 125 ° C, particularly 105 to 125 ° C. In the present invention, the softening point of the binder resin composed of the first binder resin and the second binder resin into which wax is internally added may be in the above range.

The acid value of the wax-added first binder resin is preferably 5 to 50 KOHmg / g, and more preferably 10 to 40 KOHmg / g. The acid value of the second binder resin is preferably 0 to 10 KOHmg / g, and more preferably 1 to 5 KOHmg / g. In particular, when a polyester resin is used, by using a resin having such an acid value, the dispersibility of various colorants and the like can be improved, and a toner having a sufficient charge amount can be obtained.
The first binder resin preferably contains a component insoluble in tetrahydrofuran (THF) from the viewpoint of high temperature offset resistance. The THF-insoluble component content in the first binder resin added with wax is preferably 0.1 to 15% by weight, particularly 0.2 to 10% by weight, and more preferably 0.3 to 5% by weight.

(Coloring agent)
As the colorant used in the present invention, known pigments and dyes conventionally used as colorants for full-color toners can be used. For example, carbon black, aniline blue, calcoil blue, chrome yellow, ultramarine blue, DuPont oil red, quinoline yellow, methylene blue chloride, copper phthalocyanine, malachite green oxalate, lamp black, rose bengal, C.I. I. Pigment red 48: 1, C.I. I. Pigment red 122, C.I. I. Pigment red 57: 1, C.I. I. Pigment red 184, C.I. I. Pigment yellow 97, C.I. I. Pigment yellow 12, C.I. I. Pigment yellow 17, C.I. I. Pigment yellow 74, C.I. I. Solvent Yellow 162, C.I. I. Pigment yellow 180, C.I. I. Pigment yellow 185, C.I. I. Pigment blue 15: 1, C.I. I. And CI Pigment Blue 15: 3. The content of the colorant in the toner particles is preferably in the range of 2 to 15 parts by weight with respect to 100 parts by weight of the total binder resin. It is preferable from the viewpoint of dispersibility that the colorant is used in the form of a masterbatch dispersed in a mixed binder resin of the first binder resin and the second binder resin used. The addition amount of the masterbatch may be an amount such that the amount of the colorant contained is within the above range. The colorant content in the masterbatch is preferably 20 to 40% by weight.

(Charge control agent)
In the toner of the present invention, a known charge control agent conventionally used in full color toners may be used.
For example, nigrosine dyes, triphenylmethane dyes, chromium-containing metal complex dyes, molybdate chelate pigments, rhodamine dyes, alkoxy amines, quaternary ammonium salts (including fluorine-modified quaternary ammonium salts), alkylamides, phosphorus Simple substance or compound, tungsten simple substance or compound, fluorine-based activator, salicylic acid metal salt, metal salt of salicylic acid derivative, and the like. Specifically, Bontron 03 of a nigrosine dye, Bontron P-51 of a quaternary ammonium salt, Bontron S-34 of a metal-containing azo dye, E-82 of an oxynaphthoic acid metal complex, E-84 of a salicylic acid metal complex , Phenolic condensate E-89 (above, Orient Chemical Industries, Ltd.), quaternary ammonium salt molybdenum complex TP-302, TP-415 (above, Hodogaya Chemical Co., Ltd.), quaternary ammonium salt copy Charge PSY VP2038, copy blue PR of triphenylmethane derivative, copy charge of quaternary ammonium salt NEG VP2036, copy charge NX VP434 (manufactured by Hoechst), LRA-901, LR-147 which is a boron complex (Nippon Carlit) Manufactured), copper phthalocyanine, perylene, quinacridone, azo series Fee, a sulfonic acid group, a carboxyl group, and polymer compounds having a functional group such as quaternary ammonium salts. Of these, substances that control the negative polarity of the toner are particularly preferably used.

  The amount of charge control agent used is determined by the type of binder resin, the presence or absence of additives used as necessary, and the toner production method including the dispersion method, and is not uniquely limited. Preferably, it is used in the range of 0.1 to 10 parts by weight with respect to 100 parts by weight of the binder resin. The range of 0.2 to 5 parts by weight is preferable. When the amount exceeds 10 parts by weight, the chargeability of the toner is too high, the effect of the charge control agent is reduced, the electrostatic attraction with the developing roller is increased, the developer fluidity is lowered, and the image density is lowered. Invite.

(External additive)
In the present invention, various inorganic fine particles can be used as an external additive for assisting fluidity and developability.
Specific examples of inorganic fine particles include, for example, silicon oxide, zinc oxide, tin oxide, silica sand, titanium oxide, clay, mica, wollastonite, diatomaceous earth, chromium oxide, cerium oxide, bengara, antimony trioxide, magnesium oxide, Examples thereof include zirconium oxide, barium sulfate, barium carbonate, calcium carbonate, silicon carbide, and silicon nitride.

(Manufacturing method)
The toner of the present invention is a toner having a desired particle size by mixing, kneading, pulverizing, and classifying the first binder resin, the second binder resin, and the colorant in which the hydrocarbon wax is internally added by a conventional method. Particles (colored resin particles) can be obtained and mixed with an external additive.

(Developer configuration)
As the developing roller, a roller coated with an elastic rubber layer is used, and a surface coat layer made of a material that is easily charged to a polarity opposite to that of the toner is provided on the surface. The elastic rubber layer is set to a hardness of 60 degrees or less according to JIS-A in order to prevent toner deterioration due to pressure concentration at the contact portion with the layer regulating member. The surface roughness Ra is set to 0.3 to 2.0 μm, and a necessary amount of toner is held on the surface. The developing roller rotates in the clockwise direction, and conveys the toner held on the surface to a position facing the layer regulating member and the photoconductor.
The layer regulating member is provided at a position lower than the contact position between the supply roller and the developing roller. The layer regulating member is made of a metal leaf spring material such as SUS or phosphor bronze, and the free end is brought into contact with the surface of the developing roller with a pressing force of 20 to 50 N / m. The film is thinned and charged by frictional charging. Further, a regulation bias having a value offset in the same direction as the toner charging polarity with respect to the developing bias is applied to the layer regulating member in order to assist frictional charging.

The rubber elastic body constituting the surface of the developing roller is not particularly limited. For example, styrene-butadiene copolymer rubber, acrylonitrile-butadiene copolymer rubber, acrylic rubber, epichlorohydrin rubber, urethane rubber, silicon rubber, A blend of two or more of these may be mentioned. Among these, a blend rubber of epichlorohydrin rubber and acrylonitrile-butadiene copolymer rubber is preferably used.
The developing roller used in the present invention is manufactured, for example, by covering the outer periphery of a conductive shaft with a rubber elastic body. The conductive shaft is made of a metal such as stainless steel, for example.

Preparation of static elimination sheet The static elimination sheet of the present invention can be produced as follows, but the following is only an example and is not particularly limited.
First, although it is a raw material, it consists of resin and a conductivity-imparting material.
The resin is not particularly limited, and examples thereof include polyvinylidene fluoride, polyimide, polycarbonate, and ethylene / tetrafluoroethylene.
Next, in order to impart conductivity, the conductive filler to be blended is not particularly limited as long as it is a fine powder such as conductive or semiconductive, but ketjen black (contactive furnace carbon black), acetylene Conductive and semiconductive fine powders such as carbon black such as black, stannic oxide, indium oxide, potassium titanate, black titanate, and titanate whiskers can be exemplified and are not particularly limited. The amount of the conductive filler to be used is not particularly limited and may be appropriately selected according to the volume electric resistance value. Usually, it may be about 5 to 20% by weight based on the total weight of the amount used. In addition, in order to stabilize the volume electric resistance value, it may be possible to use a combination of conductive carbon and metal oxide, but this is not particularly limited.

  In this invention, you may mix | blend an appropriate component as needed besides the polyvinylidene fluoride resin and the conductive filler. For example, a lubricant such as wax, silicone oil, and low molecular weight vinylidene fluoride can be appropriately blended. The lubricant is usually blended in an amount of, for example, 1.5% by weight or less, preferably about 0.5 to 1.5% by weight, based on the total weight of the raw materials used. Of course, the lubricant need not be used. .

  First, each raw material is blended. The method for blending is not particularly limited, and examples thereof include a mixing blend method. Although there is no restriction | limiting in particular as a mixer used for mixing blend, When considering disperse | distributing conductive carbon uniformly, the extruder etc. which have a twin screw are preferable. Furthermore, when it is desired to improve the dispersibility, the polyvinylidene fluoride resin powder and the metal oxide or conductive carbon powder may be mixed physically and mechanically, for example, by a method such as hybridization. Although this is possible, this is not particularly limited.

  The raw material thus mixed and blended is usually extruded into pellets. Since blended raw materials, for example, raw materials formed into pellets as described above, may foam during film formation in an undried state, the moisture content is about 0.05% by weight or less if necessary. You may dehumidify and dry so that it may become. Further, it is often preferable to perform mixing and pelletization in a substituting atmosphere of a gas having poor reactivity such as nitrogen gas or carbon dioxide gas or an inert gas such as helium gas because the fluctuation of the molecular weight of the resin is suppressed. Note that the volume electrical resistance value of the resulting pellet may vary depending on the mixing blend. The blends thus obtained are often more preferred when they are dried in the same poorly reactive gas or inert gas as described above. Mixing and pelletizing are preferably performed at a low temperature. If necessary, the addition of a lubricant can often prevent a decrease in molecular weight, but it is not particularly necessary to add a lubricant.

The blended and, if necessary, pelletized material is then deposited on a film. The film forming method is not particularly limited, but the extrusion film forming method is preferable. Although the volume electric resistance value of the obtained film is mainly determined by the amount of the conductive filler to be blended, the volume electric resistance value of each part of the film varies considerably depending on the film forming conditions. Therefore, in order to control the volume electrical resistance value to a predetermined value and to keep the fluctuation range of the volume electrical resistance value of each part of the film within a certain value, sufficient attention must be paid to the film forming conditions. For example, when performing extrusion film formation, it may vary depending on the fluidity, viscosity, etc. of the blended raw material, the pressure applied in the extruder, and other factors, so the screw shape, extrusion amount, temperature control, etc. are accurate. It is desirable to do it well. At this time, in order to control the pressure in the extruder, the resin may be fed into the extruder via a gear pump. Any gear pump may be used as long as it can lead the molten resin quantitatively to a die, and a commercially available one can be used. In particular, the fluctuation of the volume electric resistance value generally tends to increase in the direction perpendicular to the extrusion direction, and is not particularly limited. However, it is preferable to control the temperature in detail during extrusion.
A static elimination sheet can be obtained by sequentially cutting the film obtained in this way with a predetermined length.

  The volume resistance of the static elimination sheet was measured according to ASTM (American Society for Testing and Materials) D 149 measurement procedure.

FIG. 1 is a sectional view of a developing device and a process cartridge unit according to an embodiment of the present invention.
The developing device includes a toner storage chamber (101) for storing toner and a toner supply chamber (102) provided below the toner storage chamber (101). A roller (103), a layer regulating member (104) provided in contact with the developing roller (103), and a supply roller (105) are provided. The developing roller (103) is disposed in contact with the photosensitive drum (2), and a predetermined developing bias is applied from a high voltage power source (not shown). A toner stirring member (106) is provided in the toner storage chamber (101), and rotates in a counterclockwise direction. In the axial direction, the toner agitating member (106) has a large area on the toner conveyance surface by rotational driving at a portion (106A) where the tip portion does not pass near the opening, and the contained toner can flow sufficiently. Stir. Further, the portion (106B) where the tip portion passes in the vicinity of the opening has a shape in which the area of the toner conveying surface by rotational driving is reduced, and an excessive amount of toner is guided to the opening (107). It is preventing. The toner in the vicinity of the opening (107) is moderately loosened by the toner stirring member (106B), passes through the opening (107) by its own weight, and drops and moves to the toner supply chamber (102). The surface of the supply roller (105) is covered with a foam material having a structure having pores (cells), and the toner conveyed into the toner supply chamber (102) is efficiently attached and taken in and developed. Toner deterioration due to pressure concentration at the contact portion with the roller (103) is prevented. The foam material is set to an electric resistance value of 10 ³ to 10 ¹⁴ Ω. A supply bias having a value offset in the same direction as the toner charging polarity with respect to the developing bias is applied to the supply roller (105). The supply bias acts in a direction in which the toner preliminarily charged at the contact portion with the developing roller (103) is pressed against the developing roller (103). However, the direction of the offset is not limited to this, and the offset may be 0 or the direction of the offset may be changed depending on the type of toner. The supply roller (105) rotates counterclockwise to apply and supply the toner adhered to the surface to the surface of the developing roller (103). A roller coated with an elastic rubber layer is used as the developing roller (103), and a surface coat layer made of a material that is easily charged to a polarity opposite to that of the toner is provided on the surface. The elastic rubber layer is set to a hardness of 50 degrees or less according to JIS-A in order to keep the contact state with the photosensitive drum (2) uniform, and further to 10 ³ to 10 ¹⁰ Ω in order to act a developing bias. Set to electrical resistance value. The surface roughness Ra is set to 0.2 to 2.0 μm, and a necessary amount of toner is held on the surface. The developing roller (103) rotates counterclockwise and conveys the toner held on the surface to a position facing the layer regulating member (104) and the photosensitive drum (2). The layer regulating member (104) is made of a metal leaf spring material such as SUS304CSP, SUS301CSP, or phosphor bronze, and the free end is brought into contact with the surface of the developing roller (103) with a pressing force of 10 to 100 N / m. The toner that has passed under the pressing force is thinned and charged by frictional charging. Further, a restriction bias having a value offset from the developing bias in the same direction as the charging polarity of the toner is applied to the layer restriction member (104) in order to assist frictional charging. The photosensitive drum (2) rotates in the clockwise direction. Therefore, the surface of the developing roller (103) moves in the same direction as the traveling direction of the photosensitive drum (2) at a position facing the photosensitive drum (2). To do. The thinned toner is conveyed to a position facing the photosensitive drum (2) by the rotation of the developing roller (103), and the developing bias applied to the developing roller (103) and the photosensitive drum (2). In accordance with the latent image electric field formed by the electrostatic latent image, it moves to the surface of the photosensitive drum (2) and is developed. In the portion where the toner remaining on the developing roller (103) without being developed on the photosensitive drum (2) returns to the toner supply chamber (102) again, the charge eliminating sheet (108) is placed on the developing roller (103). It is provided in contact with.

  Next, the present invention will be described in more detail with reference to examples. However, the present invention is not limited to the following examples.

Production of first binder resin As a vinyl monomer, 600 g of styrene, 110 g of butyl acrylate, 30 g of acrylic acid, and 30 g of dicumyl peroxide as a polymerization initiator were placed in a dropping funnel. Among polyester monomers, as polyols, 1230 g of polyoxypropylene (2.2) -2,2-bis (4-hydroxyphenyl) propane, polyoxyethylene (2.2) -2,2-bis (4 -Hydroxyphenyl) propane 290 g, isododecenyl succinic anhydride 250 g, terephthalic acid 310 g, 1,2,4-benzenetricarboxylic anhydride 180 g, dibutyltin oxide 7 g as esterification catalyst, wax as paraffin wax (melting point 73.3 ° C., differential 340 g (11.0 parts by weight with respect to 100 parts by weight of charged monomer) of 340 g of endothermic peak at the time of temperature rise measured by a scanning calorimeter at 4 ° C., thermometer, stainless steel stirrer, flow-down condenser, Place in a 5 liter four-necked flask equipped with a nitrogen inlet tube and a mantle heater In a nitrogen atmosphere, with stirring at a temperature of 160 ° C., it was added dropwise over one hour a mixture of the vinyl monomer resins and the polymerization initiator from the dropping funnel. The addition polymerization reaction was aged for 2 hours while maintaining the temperature at 160 ° C., and then the temperature was raised to 230 ° C. to perform the condensation polymerization reaction. The degree of polymerization was tracked by the softening point measured using a constant load extrusion capillary rheometer, and when the desired softening point was reached, the reaction was terminated to obtain Resin H1. The resin softening point was 130 ° C.

Production of Second Binder Resin As polyol, 2210 g of polyoxypropylene (2.2) -2,2-bis (4-hydroxyphenyl) propane, 850 g of terephthalic acid, 120 g of 1,2,4-benzenetricarboxylic anhydride and esterification As a catalyst, 0.5 g of dibutyltin oxide is placed in a 5-liter four-necked flask equipped with a thermometer, a stainless steel stirrer, a flow-down condenser and a nitrogen inlet tube, and heated to 230 ° C. in a mantle heater under a nitrogen atmosphere. A condensation polymerization reaction was performed. The degree of polymerization was monitored by the softening point measured using a constant load extrusion capillary rheometer, and when the desired softening point was reached, the reaction was terminated to obtain Resin L1. The resin softening point was 115 ° C.

Preparation of toner particles LR-147 (manufactured by Nippon Carlit Co., Ltd.) is 1 with respect to 100 parts by mass of the binder resin composed of the first and second binder resins (ratio of the second binder weight 100 to the first binder weight 111). .75 parts, C.I. I. A master batch corresponding to 4 parts by mass of Pigment Red 57-1 was sufficiently mixed with a Henschel mixer, and then melt-kneaded using a biaxial extrusion kneader (PCM-30: manufactured by Ikekai Tekko Co., Ltd.). The kneaded product was rolled to a thickness of 2 mm with a cooling press roller, cooled with a cooling belt, and then roughly pulverized with a feather mill. Then, after pulverizing with a mechanical pulverizer (KTM: Kawasaki Heavy Industries, Ltd.) to an average particle size of 10-12 μm and further pulverizing with a jet pulverizer (IDS: manufactured by Nippon Pneumatic Co., Ltd.) Then, fine powder classification was performed using a rotor type classifier (Teplex type classifier type: 100ATP: manufactured by Hosokawa Micron Corporation) to obtain colored particles 1. The particle diameter of the colored particles 1 was 7.5 μm.
Colored particles 2 to 11 were obtained under the same conditions as those of the colored particles 1 except for the addition amount of the charge control agent and the classification rotational speed.
Further, colored particles 12 and 13 were obtained in the same manner as the colored particle 2 except that the composition of 100 parts by weight of the binder resin composed of the first and second binder resins in the colored particle 2 was changed as follows.
Colored particles 12
Ratio of second binder weight 100 to first binder weight 29 Colored particles 13
Ratio of second binder weight 100 to first binder weight 256

A desired amount (mass part) of silica 1 and silica 2 (R974 manufactured by Aerosil Co., Ltd.) having a particle size shown in Table 1 as inorganic fine particles is added to 100 parts by mass of the colored resin particles 1 to 13 and mixed with a Henschel mixer. Processing was performed to obtain magenta toner particles 1 to 15. See Table 1 for each condition. The silica used as silica 1 is as follows.
Particle size 40nm Nippon Aerosil RX50
Particle size 120nm Shin-Etsu Chemical X-24
Particle size 18nm Nippon Aerosil R972

Example 1
Preparation of neutralization sheet 95% by weight of polyvinylidene fluoride resin and 5% by weight of acetylene black were blended by a hybridization system in a nitrogen gas atmosphere, and the resulting blend was subsequently equipped with a twin screw in a nitrogen gas atmosphere. A pellet-shaped raw material was prepared using an extruder. This pellet raw material was put into a 65 mmφ extruder with L / D = 29 and melt extruded through a gear pump. Next, the film was regulated and cooled to form a film having a thickness of 0.12 mm. The film thus obtained was cut into a desired dimension to obtain a static elimination sheet having a width of 230 mm, a height of 15 mm and a thickness of 0.12 mm. The volume resistivity of this static elimination sheet was 1.6 × 10 ¹² Ω · cm when a voltage of 100 V was applied.

  Using a Ricoh color laser printer IPSIO CX2500 having a one-component developing device, the magenta toner 1 obtained by the production of the toner particles was put, the above-mentioned charge-removing sheet was attached to the above-mentioned image device, and image evaluation was performed as follows. Table 2 shows the characteristics of the toner and the charge removal sheet, and Table 3 shows the evaluation results.

Image evaluation Evaluation items and evaluation criteria are shown below. The evaluation was performed after running 3000 sheets in an 80% environment at 30 ° C. in a mode with a printing rate of 1% 1 P / J.
・ Half unevenness: Visual evaluation of uneven image after collecting half image ○ No problem × Quality problem ・ Toner spill: Visual evaluation of toner spill on neutralizing sheet mounting member ○ No problem × Quality problem ・ Adherence: Half image Evaluate the presence or absence of vertical white streaks in the image ○ 0 × 1 or more · Separability: Evaluate paper wrapping in the fixing system when collecting solid images ○ Pass without wrapping × Roll around jammed roller and toner: In-machine dirt after running 3000 sheets in 30% 80% environment ○ No in-machine dirt × In-machine dirt / Half texture: Visual evaluation of shading unevenness at the time of half image collection ○ No problem × Shading shading has uneven quality Yes

Examples 2-5, Comparative Examples 1-10
The neutralization toner of Example 1 was used except that the amount of acetylene black, which is a conductive material in the production of the neutralization sheet of Example 1, was changed to the amount described in Table 2, using the magenta toner described in Table 2 as the toner. Evaluation was conducted in the same manner as in Example 1 using a static elimination sheet prepared in the same manner as the sheet. Table 2 shows the characteristics of the toner and the charge removal sheet, and Table 3 shows the evaluation results.

It is sectional drawing of the process cartridge which has the image development apparatus of this invention. It is an equivalent circuit used for the measurement of toner impedance. It is sectional drawing which shows the example of the evaluation apparatus used for the measurement of the frictional force between toner particles. It is a figure of the conical rotor used for the measurement of the frictional force between toner particles.

Explanation of symbols

2 Photosensitive drum 101 Toner storage chamber 102 Toner supply chamber 103 Developing roller 104 Layer regulating member 105 Supply roller 106 Toner stirring member 107 Opening 108 Static elimination sheet

Claims (6)

At least an image bearing member on which an electrostatic latent image is formed is attached with a pulverized toner containing wax, and a developing roller for visualizing the electrostatic latent image, and a discharging sheet for discharging the charge held by the toner by contacting the developing roller. In the one-component developing device, the volume resistance R (Ω · cm) of the static eliminating sheet and the impedance Z (Ω) of the toner satisfy the relationship of the following formulas (1) to (3), and the frictional force between the toner particles is 2: A one-component developing device having a viscosity of 0.0 to 2.5 mNm.
Formula (1) 10 <Log ₁₀ R <14
Formula (2) 8.00 <Log ₁₀ Z <10.70
Formula (3) −1.5 × Log ₁₀ R + 23.5 <Log ₁₀ Z <−1.5 × Log ₁₀ R + 31.0   The one-component developing device according to claim 1, wherein the toner has a wax content of 3.0 to 7.0% by mass and is used in an image forming apparatus having a fixing system that does not use oil.   3. The one-component developing device according to claim 1, wherein the toner has an average circularity of 0.900 to 0.930 and a volume average particle diameter of 6 to 10 μm.   4. The one-component developing device according to claim 1, wherein a space ratio obtained from a displacement when a weight is applied to the toner is 56 to 58%.   5. A process cartridge comprising at least the one-component developing device according to claim 1.   An image forming apparatus comprising at least the one-component developing device according to claim 1.

Images