JP6176157B2 - Toner for developing electrostatic image and electrophotographic toner cartridge - Google Patents

Description

  The present invention relates to an image forming method, and more particularly to an image forming method in which image density and solid followability are improved and toner layer formation failure on a paper fog and a developing sleeve is suppressed well.

Conventionally, in electrophotography, as a method of developing an electrostatic latent image on an electrophotographic photosensitive member with a toner containing a magnetic material, a toner layer is formed on a developing sleeve and the toner is jumped and developed on the photosensitive member. A contact development method is known.
In this developing system, a developing bias voltage in which alternating current and direct current are superimposed is applied to the developing sleeve from a developing bias power source. Then, the electrostatic latent image is developed by applying the toner charged by frictional charging at the contact point between the developer layer thickness regulating member and the developing sleeve to the electrostatic latent image on the surface of the photosensitive drum.

  JP-A-2000-35692 discloses a specific hydrotalcite as an external additive for the purpose of preventing image defects such as reduction in image density and fogging and obtaining high transfer efficiency in a jumping development system. The use of a similar compound is disclosed, and in the examples, the use of a urethane rubber blade as a toner regulating member (charging blade) is disclosed.

JP 2000-35692 A

However, according to the study by the present inventors, in the jumping development method, the magnetic toner on the developing sleeve is triboelectrically charged with a urethane rubber blade to develop the electrostatic latent image on the photosensitive member. It was found that it was insufficient in terms of image density reduction, solid followability and poor toner layer formation on the developing sleeve.
An object of the present invention is to provide a toner for developing an electrostatic charge image that improves the image density and the solid followability, and that satisfactorily suppress the formation of a paper fog and a toner layer on the developing sleeve.

  In view of the above problems, as a result of intensive studies by the present inventors, an electrophotographic toner having a toner containing a magnetic material, a developing sleeve, and a toner layer thickness regulating member made of stainless steel that charges the toner on the developing sleeve In the toner for developing an electrostatic charge image used in a cartridge, the toner charged by the stainless steel toner layer thickness regulating member contains a magnetic material having a specific shape and has a hydrotalcite compound on the surface. It has been found that the above-mentioned problems can be solved by having it.

  In addition, the present inventors have a specific shape as the magnetic material in an electrophotographic toner cartridge having a toner containing a magnetic material, a developing sleeve, and a toner layer thickness regulating member for charging the toner on the developing sleeve. It has been found that the above problem can be solved by employing a magnetic material, adding a hydrotalcite compound to the toner surface, and using the toner layer thickness regulating member as a specific material.

That is, the gist of the present invention resides in the following [1] to [6].
[1] An electrostatic charge image developing toner used in an electrophotographic toner cartridge having a toner containing a magnetic material, a developing sleeve, and a stainless steel toner layer thickness regulating member for charging the toner on the developing sleeve. The toner for developing an electrostatic charge image, wherein the magnetic material has a hexahedral shape, and the toner has a hydrotalcite compound on the surface thereof.
[2] The electrostatic image developing toner according to [1], wherein the toner layer regulating member is coated with silicon rubber.
[3] The toner for developing an electrostatic charge image according to [1] or [2], wherein the developing sleeve is a Mo-treated aluminum base.
[4] An electrophotographic toner cartridge having a toner containing a magnetic material, a developing sleeve, and a toner layer thickness regulating member for charging the toner on the developing sleeve, wherein the magnetic material has a hexahedral shape, and 2. The electrophotographic toner cartridge according to claim 1, wherein the toner has a hydrotalcite compound on a surface thereof, and the toner layer thickness regulating member is made of stainless steel.
[5] The electrophotographic toner cartridge according to [4], wherein the toner layer regulating member is covered with silicon rubber.
[6] The electrophotographic toner cartridge according to [4] or [5], wherein the developing sleeve is a Mo-treated aluminum base.

According to the present invention, it is possible to improve the image density and the solid followability and to satisfactorily suppress the formation of a toner fog on the paper fog and the developing sleeve.
In addition, when the developing sleeve is an aluminum base that has been subjected to Mo treatment, the above-described effects can be exhibited more remarkably.

It is the schematic of an example of the image development apparatus used for this invention.

The present invention provides the following <1. As described in detail in Configuration of Electrostatic Image Developing Toner>, the toner contains a magnetic material, the magnetic material has a hexahedral shape, and is represented by the following formula (1) on the surface of the toner. Having a hydrotalcite compound, <2. As described in detail in <Configuration of Image Forming Apparatus and Electrophotographic Toner Cartridge>, the effect of the present invention is exhibited when used in an electrophotographic toner cartridge having a toner layer thickness regulating member made of stainless steel.
Although details are unknown, it was found that the effects of the present invention are exhibited only when all of these conditions are satisfied, as can be seen from the examples and comparative examples described later.

<1. Configuration of toner for developing electrostatic image>
(1-1. Magnetic material)
In the present invention, the magnetic substance contained in the toner has a hexahedral shape. By using a magnetic body having a hexahedral shape, an excellent effect can be exhibited in terms of image density and toner amount detection sensor sensitivity.
Examples of the magnetic material include magnetic metals such as iron, steel, nickel, and cobalt, and alloys of these with manganese, chromium, rare earth elements, and the like (for example, nickel-iron alloy, cobalt-iron alloy, aluminum-iron alloy, etc.) And magnetic oxides such as ferrite and magnetite are used. Among these, magnetite is preferable because it is advantageous in terms of stable characteristics and low toxicity.

The average particle diameter of the magnetic material is not particularly limited, but the lower limit is usually 0.05 μm or more,
Preferably it is 0.10 μm or more, more preferably 0.15 μm or more. On the other hand, the upper limit is usually 0.50 μm or less, preferably 0.45 μm or less, and more preferably 0.40 μm or less.
The content of the magnetic substance with respect to the toner particles is not particularly limited, but the lower limit is usually 30 parts by mass or more, preferably 35 parts by mass or more, more preferably 40 parts by mass with respect to 100 parts by mass of the toner particles. That's it. On the other hand, the upper limit is usually 130 parts by mass or less, preferably 120 parts by mass or less, and more preferably 110 parts by mass or less. If the content of the magnetic material with respect to the toner particles is too small, the coloring power may be insufficient, and the image density may be insufficient, or the magnetic force may be insufficient, resulting in insufficient frictional charging with the sleeve and causing paper fogging. On the other hand, if the amount is too large, the magnetic force is too strong, and the toner may not be developed from the sleeve to the drum, resulting in insufficient image density.

In the present invention, the toner may contain a magnetic material other than the magnetic material having a hexahedral shape as long as the effects of the present invention are not impaired.
As other magnetic materials that can be used in the present invention, known magnetic materials can be used. Specifically, magnetite, maghemite, intermediates and mixtures of magnetite and maghemite, iron oxides such as ferrite; metals such as iron, cobalt, nickel, or these metals and aluminum, cobalt, copper, lead, Examples include alloys with metals such as magnesium, tin, zinc, antimony, beryllium, bismuth, cadmium, calcium, manganese, selenium, titanium, tungsten, vanadium, and mixtures thereof. Among these, magnetite, maghematite, or an intermediate between magnetite and maghematite is preferable.

(1-2. Compound particles)
In the present invention, a hydrotalcite compound is used on the surface of the toner.
The hydrotalcite compound particles used in the present invention are not particularly limited as long as it is a hydrotalcite represented by the following general formula (1).
M1 ²⁺ _y1 M2 ²⁺ _y2 … Mj ²⁺ _yj L1 ³⁺ _x1 L2 ³⁺ _x2 … Lk ³⁺ _xk (OH) ₂ · (X / n) A ⁿ⁻ · mH ₂ O (1)
In formula (1), 0 <[X = (x1 + x2 +... + Xk)] ≦ 0.5, Y = (y1 + y2 +... + Yj) = 1−X, j and k are integers greater than or equal to 1, M1 ²⁺ , M2 ^2+, ... and Mj ²⁺ different divalent metal ions, L1 ^3+, L2 ^3+, ... and Lk ³⁺ are different trivalent metal ion, a ^n-represents an n-valent anion, m ≧ 0.
That is, a solid solution in which two or more divalent metals and one or more trivalent metals are used. Moreover, one type of anion may be sufficient and you may have multiple types.

More specifically, the hydrotalcite compound is a compound represented by the following general formula (2).
Mg ²⁺ _y1 M2 ²⁺ _y2 Mj ²⁺ _yj Al ³⁺ _x1 L2 ³⁺ _x2 Lk ³⁺ _xk (OH) ₂ · (X / n) A ⁿ⁻ · mH ₂ O (2)
In formula (2), 0 <[X = (x1 + x2 +... + Xk)] ≦ 0.5, Y = (y1 + y2 +... + Yj) = 1−X, j and k are integers greater than or equal to 1, M2, M3,. Are different metals selected from the group consisting of Zn, Ca, Ba, Ni, Sr, Cu and Fe, L2, L3... And Lk are different metals selected from the group consisting of B, Ga, Fe, Co and In, A ⁿ⁻ represents an n-valent anion, and m ≧ 0.

Moreover, it is more preferable that the hydrotalcite compound contains Zn as a divalent metal other than Mg.
As the An ⁿ⁻ (n-valent anion) of the hydrotalcite compound used in the present invention, CO ₃ ²⁻ , OH ⁻ , Cl ⁻ , I ⁻ , F ⁻ , Br ⁻ , SO ₄ ²⁻ , HCO ₃ ^-, CH ₃ CO
O ^- and NO ₃ ^- are exemplified, and a single species or a plurality of species may be present.

The hydrotalcite compound preferably has water in its molecule.

The specific surface area of the hydrotalcites used in the present invention is preferably 1 to 50 m ² / g or more, more preferably 3 to 20 m ² / g.
In accordance with the BET method, the specific surface area was determined by adsorbing nitrogen gas on the sample surface using a specific surface area measuring device Auto Soap 1 (manufactured by Yuasa Ionics) and calculating the specific surface area using the BET multipoint method.

The hydrotalcite compound used in the present invention may be subjected to a hydrophobization treatment with a surface treatment agent as necessary. As the surface treatment agent, higher fatty acids, coupling agents, esters, oils such as silicone oil, and the like can be used.
Of these, higher fatty acids are preferably used, and specific examples include stearic acid, oleic acid, and lauric acid.

  The amount of the hydrotalcite compound added to the toner particles is not particularly limited as long as the effect of the present invention is not impaired, but the lower limit is usually 0.01 parts by mass or more, preferably 100 parts by weight of the toner particles. Is 0.02 parts by mass or more, more preferably 0.03 parts by mass or more. On the other hand, an upper limit is 0.5 mass part or less normally, Preferably it is 0.4 mass part or less, More preferably, it is 0.3 mass part or less. When the addition amount is less than 0.01 parts by mass, the image density may be insufficient, and when it exceeds 0.5 parts by mass, the solid followability and the toner layer formation on the developing sleeve may be insufficient. is there.

(1-3. Manufacturing method of toner particles)
The method for producing the toner particles is not particularly limited, and examples thereof include a production method by a wet kneading method such as a melt-kneading pulverization method, a suspension polymerization method, an emulsion polymerization aggregation method, or a dissolution suspension method.
When producing by the melt-kneading pulverization method, it can be performed according to a conventionally known method. That is, if necessary, a wax (release agent), a colorant and the like are dry mixed with the binder resin, magnetic powder, and charge control agent, and then melt-kneaded with an extruder or the like, then pulverized and classified, and toner This is a method for obtaining particles. Specifically, a predetermined amount of a binder resin, a colorant, and other components as required are mixed and mixed. Examples of the mixing apparatus include a double-con mixer, a V-type mixer, a drum-type mixer, a super mixer, a Henschel mixer, and a Nauter mixer.

  Next, the blended and mixed toner raw materials are melt-kneaded to melt the resins, and colorants and the like are dispersed therein. In the melt-kneading step, for example, melt-kneading can be performed with a pressure kneader, a Banbury mixer, a closed kneader, a uniaxial or biaxial extruder, or the like. Furthermore, the colored resin composition obtained by melt-kneading the toner raw material is rolled by a two-roll roll after melt-kneading, and then cooled through a cooling step of cooling by water cooling or the like.

  The cooled product of the colored resin composition obtained above is then pulverized to a desired particle size in a pulverization step. In the pulverization process, first, coarse pulverization is performed with a crusher, hammer mill, feather mill, etc., and further finely pulverized with a jet mill, high-speed rotor rotary mill, etc. The toner particles can be obtained by classification using a classifying microplex, DS separator, or the like.

In the suspension polymerization method, a composition containing a polymerizable monomer, a polymerization initiator, a colorant, and the like is suspended and dispersed in an aqueous medium and then polymerized to produce particles, and the particles are washed and dried. This is a method for obtaining toner particles.
In the emulsion polymerization aggregation method, a polymerizable monomer is emulsified in an aqueous medium containing a polymerization initiator and an emulsifier, and the polymerizable monomer is polymerized with stirring to obtain polymer primary particles, which are then colored. A method for obtaining toner particles by adding an agent and, if necessary, a charge control agent to agglomerate polymer primary particles, ripening the obtained agglomerated particles to produce particles, and washing and drying the particles. It is.
In the dissolution suspension method, a solution phase obtained by dissolving a binder resin in an organic solvent and adding and dispersing a colorant is dispersed in a water phase containing a dispersant by mechanical shearing force to form droplets. Then, the organic solvent is removed from the droplets to produce particles, and the particles are washed and dried to obtain toner particles.

  The toner can be obtained by adhering or fixing the above-described hydrotalcite-based compound particles and other external additives to the surface of the toner particles obtained by the above method. A method for attaching or fixing the external additive is not particularly limited, and a mixer generally used for toner production can be used. Specifically, the toner particles obtained by the above toner particle production method and an external additive are mixed, and uniformly stirred and mixed by a mixer such as a Henschel mixer, a V-type blender, a Redige mixer, or a Q-mixer. Is made by

  As a method for adhering or fixing the above-mentioned hydrotalcite-based compound particles to the toner particles, there is a method in which an external additive is fixed to the toner surface in addition to the method using a mixer such as the Henschel mixer. As a fixing treatment method, use of an apparatus capable of applying compressive shear stress (hereinafter referred to as a compression shearing apparatus) or an apparatus capable of melting or softening the toner particle surface (hereinafter referred to as a particle surface melting apparatus). Etc. By this treatment, the particles of the above-mentioned hydrotalcite compound are firmly fixed on the toner particle surface, so that the blocking resistance under high temperature storage is improved, and adhesion to the copier / printer member occurs even during continuous shooting. Difficult toner can be produced.

<1-4. Binder resin>
The binder resin constituting the toner particles is not particularly limited. Examples of the final resin that can be used include styrene-acrylic copolymer resins, vinyl resins, phenol resins, epoxy resins, saturated or unsaturated resins. Polyester resin, polyethylene resin, polypropylene resin, ionomer resin, polyurethane resin, silicone resin, ketone resin, ethylene-acrylate copolymer, xylene resin, polyvinyl butyral resin, styrene-alkyl acrylate copolymer, styrene-methacrylic acid Examples thereof include an alkyl copolymer, a styrene-acrylonitrile copolymer, a styrene-butadiene copolymer, and a styrene-maleic anhydride copolymer. These binder resins may be used alone or in combination.
Further, a crosslinking agent can be used during the synthesis of the binder resin in order to increase the mechanical strength of the toner particles.
Further, it is preferable to use a pre-binding resin that contains as little volatile impurities as possible.

<1-5. Colorant>
The magnetic material used in the present invention can also serve as a colorant, but a known colorant can be used in combination as necessary. Specific examples of colorants include carbon black, aniline blue, phthalocyanine blue, phthalocyanine green, Hansa yellow, rhodamine dyes, chrome yellow, quinacridone, benzidine yellow, rose bengal, triallylmethane dye, monoazo, Any known dyes and pigments such as disazo dyes and condensed azo dyes can be used alone or in combination.

Among these, carbon black as a black pigment exists as an aggregate of very fine primary particles, and when dispersed as a pigment dispersion, coarsening of particles due to reaggregation tends to occur. The degree of reagglomeration of carbon black particles correlates with the amount of impurities contained in carbon black (the degree of residual undecomposed organic matter). If there are many impurities, coarsening due to reaggregation after dispersion tends to be severe. showed that. As a quantitative evaluation of the amount of impurities, the ultraviolet absorbance of the toluene extract of carbon black measured by the following method is preferably 0.05 or less, and more preferably 0.03 or less. In general, carbon black produced by the channel method tends to have a large amount of impurities, and therefore, carbon black produced by the furnace method is preferred as the carbon black used in the present invention.

The lower limit of the content of the colorant is usually 30.1 parts by mass or more, preferably 0.3 parts by mass or more, more preferably 0.5 parts by mass with respect to 100 parts by mass of the binder resin. That's it. On the other hand, the upper limit is usually 10 parts by mass or less, preferably 8 parts by mass or less, and more preferably 5 parts by mass or less.
In addition, it is preferable to use a colorant that contains as little volatile impurities as possible.

<1-6. Wax (release agent)>
The toner may contain a wax in the toner as necessary. Known waxes can be arbitrarily used as the wax, and specific examples include the following. Petroleum wax such as paraffin wax, microcrystalline wax, petrolatum and derivatives thereof, montan wax and derivatives thereof, hydrocarbon wax and derivatives thereof according to Fischer-Tropsch method, polyolefin wax and derivatives thereof such as polyethylene and polypropylene, carnauba wax, candelilla Natural waxes such as waxes and derivatives thereof (the derivatives include oxides, block copolymers with vinyl monomers, and graft modified products), higher aliphatic alcohols, fatty acids such as stearic acid, palmitic acid, and acid amides Waxes, ester waxes, ketones, hydrogenated castor oil and derivatives thereof, vegetable waxes, animal waxes, and silicone waxes. These waxes can be used alone or in combination of two or more.

  In the case of containing the wax, the lower limit of the content is usually 0.5 parts by mass or more, preferably 1 part by mass or more, more preferably 2 parts by mass or more with respect to 100 parts by mass of the binder resin. It is. On the other hand, an upper limit is 20 mass parts or less normally, Preferably it is 15 mass parts or less, More preferably, it is 10 mass parts or less. If the wax content in the toner is too low, the offset resistance may be insufficient. If it is too high, the blocking resistance may be insufficient, or the wax may leak from the toner and contaminate the device. There is a case to do.

<1-7. Charge control agent>
The toner of the present invention may contain a charge control agent or a charge control resin from the viewpoint of imparting chargeability to the toner. Examples of the charge control agent include an azine compound (nigrosine), a quaternary ammonium salt compound, a 2: 1 type metal-containing complex (chromium complex), a monoazo metal-containing complex compound, a charge control agent using a resin, and the like. As the agent, known ones are appropriately selected and used.

<1-8. External additive>
In the present invention, silica particles may be externally added to the toner surface from the viewpoint of maintaining the fluidity and chargeability of the toner. The silica particles are not particularly limited as long as the effects of the present invention are not significantly impaired, but silica particles whose surfaces are subjected to a hydrophobizing treatment are preferable from the viewpoint of environmental stability. The hydrophobization treatment agent and the treatment method are not particularly limited, and known ones are used, respectively. However, since higher hydrophobicity can be imparted, the treatment is performed with a silicone compound or a silicone treatment agent, for example, hexamethyldisilazane, Examples include dimethylpolysiloxane, dimethyldichlorosilane, methyltriethoxysilane, and octylsilane. Hexamethyldisilazane and dimethylpolysiloxane are preferred because higher hydrophobicity can be imparted, and dimethylpolysiloxane is particularly preferred.

The average particle diameter of the silica particles is not particularly limited as long as the effects of the present invention are not significantly impaired, but the lower limit is usually 5 nm or more, preferably 10 nm or more. On the other hand, the upper limit is usually 200 nm or less, preferably 50 nm or less.
The addition amount of the silica particles is not particularly limited, but the lower limit is usually 0.1 parts by mass or more, preferably 0.3 parts by mass or more, more preferably 100 parts by mass of the toner base particles. 0.5 parts by mass or more. On the other hand, the upper limit is usually 3.0 parts by mass or less, preferably 2.5 parts by mass or less, and more preferably 2.0 parts by mass or less.

In the present invention, a higher fatty acid metal salt such as zinc stearate and a higher fatty acid amino acid ester such as lauroyl lysine may be externally added to the toner surface as wax particles from the viewpoint of filming prevention and prevention of burying of external additives. . If necessary, hydrocarbon wax particles such as polyethylene wax particles, polypropylene wax particles, and paraffin wax particles, and ester wax may be externally added.
In the present invention, in order to improve the fluidity of the toner and the charge controllability, external additives other than the above-described hydrotalcite compounds and the silica particles and wax particles can be added as necessary. Such external additive fine particles can be appropriately selected from known various inorganic or organic fine particles.

<2. Configuration of developing device and electrophotographic cartridge>
With respect to the embodiments of the developing device and the electrophotographic toner cartridge, the main configuration of the device will be described with reference to FIG. However, the embodiment is not limited to the following description, and can be arbitrarily modified without departing from the gist of the present invention.
In the present invention, either the developing device or the electrophotographic cartridge has a toner layer thickness regulating member that charges the toner on the developing sleeve and controls the toner layer thickness, and the toner layer thickness regulating member is made of stainless steel. It is. The toner layer thickness regulating member is preferably covered with silicon rubber from the viewpoint of further exerting the effects of the present invention.

<2-1. Development device>
First, an embodiment of a jumping developing apparatus used in the present invention will be described with reference to FIG. FIG. 1 is a sectional view showing the construction of a developing device used in the present invention. In FIG. 1, reference numeral 1 denotes a photosensitive drum as a latent image forming medium rotating in the direction of arrow A. As the photosensitive drum 1, a photosensitive layer provided on a conductive support such as aluminum can be used. An electrostatic latent image (or potential latent image) is formed and held by an appropriate method. An intermediate layer (blocking layer) may be provided between the conductive support of the photosensitive drum and the photosensitive layer as necessary.

A developing device is disposed opposite to the photosensitive drum 1. The developing device includes a developer supply container (hereinafter simply referred to as a container) 2, a developing sleeve 3 as a developer carrying member, and a developer regulation. A toner layer thickness regulating member 4 as means and a supply roller 5 as developer supply means are provided.
The container 2 has an opening extending in the longitudinal direction of the developing device (a direction perpendicular to the paper surface), and the developing sleeve 3 is disposed in the opening. The developing sleeve 3 is made of a nonmagnetic material such as SUS or aluminum and has a surface as described later. The developing sleeve 3 has a right substantially half circumferential surface that protrudes into the container 2 into the opening, and a left substantially half circumferential surface is exposed to the outside of the container 2 so as to be pivotally supported and horizontally provided. It is rotationally driven in the B direction. The exposed surface of the developing sleeve 3 outside the container faces the surface of the photosensitive drum 1 with a slight gap so that the electrostatic latent image on the photosensitive drum 1 is developed by the toner 6 carried and conveyed. It has become. In the present embodiment, the developer carrier embodied as the developing sleeve 3 is not limited to a cylindrical body (sleeve), but may be a rotationally driven endless belt or the like, or a rubber roller may be used. good.

A supply roller 5 is disposed behind the developing sleeve 3 so as to slide and rotate on the surface of the developing sleeve 3 that enters the container 2. The supply roller 5 rotates in the same direction as the developing sleeve 3 (arrow C in the figure) to supply the toner 6 to the developing sleeve 3 and peel the toner on the developing sleeve 3.
Further, a toner layer thickness regulating member 4 is disposed in contact with the developing sleeve 3 on the downstream side in the rotation direction of the developing sleeve 3 with respect to the closest portion between the supply roller 5 and the developing sleeve 3. The contact portion restricts the passage of the toner 6 on the developing sleeve 3. Accordingly, the non-magnetic toner 6 supplied to the vicinity of the developing sleeve 3 by the rotation of the supply roller 5 enters the contact portion between the toner layer thickness regulating member 4 and the developing sleeve 3 by the rotation of the developing sleeve 3, and the developing sleeve. 3 supported on the surface.

  Then, when the non-magnetic toner 6 passes through the contact portion between the toner layer thickness regulating member 4 and the developing sleeve 3, the nonmagnetic toner 6 is slidably contacted with the surface of the developing sleeve 3 by the toner layer thickness regulating member 4 and receives frictional charging. . The toner 6 that has been frictionally charged in this manner passes through the contact portion, is formed as a thin toner layer on the developing sleeve 3, and is carried on the developing sleeve 3 to the developing portion that faces the photosensitive drum 1.

  In the developing unit, a part of the toner is consumed by the developing operation, and the other toner is collected from the lower part of the developing sleeve 3. A seal member 9 is provided at the collection portion to allow the toner that has not been consumed by the development to pass into the container 2 and to prevent the toner 6 in the container 2 from leaking from the lower part of the container 2. Further, the collected toner on the developing sleeve 3 is peeled off at the closest portion between the supply roller 5 and the developing sleeve 3, and at the same time, new toner is supplied onto the developing sleeve 3 and the toner layer thickness regulating member is again supplied. At the abutting portion between 4 and the developing sleeve 3, the tribo is applied and the layer is thinned and conveyed to the developing portion.

  In the developing device used in the present invention, the toner is formed into a thin layer by the toner layer thickness regulating member 4 that is in contact with the developing sleeve 3. Further, the supply roller 5 and the developing sleeve 3 may be in contact with each other or may not be in contact with each other. When the supply roller 5 and the developing sleeve 3 are in contact with each other, the toner is subjected to a large stress, and therefore it is necessary to use a toner resistant to the stress. On the other hand, when the supply roller 5 and the developing sleeve 3 are not in contact with each other, it is necessary to increase the fluidity and prevent deterioration in order to improve the supply performance to the developing sleeve rather than the stress resistance.

  The developing sleeve 3 is a cylindrical base made of a nonmagnetic metal such as aluminum or stainless steel and coated with nickel or zinc. In the present invention, from the viewpoint of remarkably exhibiting the effects of the present invention, in addition to the usual coating treatment, it is preferable that a non-burnt film treatment mainly composed of molybdenum is also applied, and molybdenum zinc plating is applied. More preferably.

  The toner layer thickness regulating member 4 is formed of a resin blade such as silicon resin or urethane resin, a metal blade such as stainless steel, aluminum, copper, brass, phosphor bronze, or a blade obtained by coating such a metal blade with resin. In the present invention, it is essential to be made of stainless steel. The toner layer thickness regulating member 4 abuts on the developing sleeve 3 and is pressed against the developing sleeve 3 with a predetermined force by a spring or the like (a general blade linear pressure is 5 to 500 g / cm). The toner layer thickness regulating member 4 is preferably covered with silicon rubber from the viewpoint of improving the charging of the toner 6 by frictional charging with the toner 6.

<2-2. Electrophotographic toner cartridge>
The electrophotographic toner cartridge used in the present invention is not particularly limited as long as it has a toner containing the magnetic material of the present invention, a developing sleeve, and a toner layer thickness regulating member for charging the toner on the developing sleeve. A known configuration may be appropriately selected and used. For the developing sleeve and the toner layer thickness regulating member, <2-1. What is necessary is just to follow the content described in the developing device>.

  EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples. However, the present invention is not limited to the following examples unless it exceeds the gist. In the following examples, “part” means “part by mass”.

<Print evaluation>
As the evaluation apparatus, a printer “MultiWriter 8500N” manufactured by NEC using a commercially available magnetic one-component developing system was used. A stainless steel blade coated with silicon rubber was used as the toner layer thickness regulating member, and an aluminum substrate plated with molybdenum zinc was used as the developing sleeve.
The printer was installed in an atmosphere of a temperature of 23 ° C. and a relative humidity of 50%, and 640 g of toner was mounted, and 14,000 sheets were continuously printed at a printing rate of 5%.
Standard paper (lightness 92, paper thickness 70 g / m ² , size A4) was used for the printing test.

<Image density evaluation>
The image density on the printed matter was measured using a Macbeth densitometer RD914 manufactured by Macbeth. Measure the image density at the initial printing and printing every 2,000 sheets with a Macbeth densitometer, the print density is less than 1.2 x, the print density is 1.2 or more and less than 1.4, the print density Of 1.4 or more was judged as ◯.

<Paper cover evaluation>
For paper fog on printed matter, measure the whiteness of the standard paper before and after printing using Nippon Denshoku SE-6000 (standard light / viewing angle: C / 2, equipped with UV cut filter 420nm), and the difference The paper cover was calculated. At the time of initial printing and at the time of printing every 2,000 sheets, for each paper fog, less than 0.8 was judged as ◯, 0.8 or more and less than 1.5 as Δ, and 1.5 or more as x.

<Evaluation of solid trackability>
Further, at the time of initial printing, every 2,000 sheets were printed, an image pattern on which the printing surface was printed at a printing rate of 100% was taken, and toner followability was confirmed. The entire surface is firmly covered with toner, where there is no difference in image density between the leading edge and the trailing edge of the paper relative to the printing direction of the paper, and the leading edge is covered with toner, The image density is slightly lower at the edges, and the difference in image density between the leading edge and the trailing edge is barely visible Δ, and the difference in image density between the leading edge and the trailing edge is clearly different visually. X.

<Evaluation of defective toner layer formation>
Also, at the time of initial printing, when printing every 2,000 sheets, an image pattern on which the printing surface is printed at a printing rate of 100% is taken, and the toner layer formation state on the developing sleeve is compared with the print sample to compare the toner. A layer formation failure was confirmed. The toner layer on the developing sleeve is uniformly formed, and the print sample is completely covered with toner, and the image density is uniform and no difference is observed. Although the image is slightly observed visually, the print sample is completely covered with toner, the image density is uniform and no difference is observed, and the wavy unevenness is visually observed in the toner layer formation on the developing sleeve. An x mark indicates that the image density is clearly recognized and the image density is wavy on the print sample.

<Example 1>
A negatively chargeable magnetic one-component toner was prepared according to the following blending ratio.
70 parts of styrene-acrylic resin A (softening point temperature: 155 ° C., glass transition temperature: 53 ° C., main component: styrene / butyl acrylate)
30 parts of styrene-acrylic resin B (softening point temperature: 139 ° C., glass transition temperature: 56 ° C., main component: styrene / butyl acrylate)
Charge control agent (manufactured by Orient Chemical Industries, Ltd. S34) 1 part Magnetic powder A (hexahedral magnetite ^{BET: 7.5m 2 /g,Hc:93.5Oe,σs:85Am 2 / kg} , σr: 9Am 2 / kg) 95 parts ・ Ester wax (WEP5 manufactured by NOF Corporation) 6 parts After mixing the above raw materials with a high speed mixer, melt kneading with a twin screw extruder, coarsely pulverizing with a hammer mill, and finely pulverizing with a mechanical pulverizer To obtain toner particles A having a volume average particle diameter of 9 μm.

The external additive was mixed with a high-speed mixer at the following blending ratio to obtain developer A.
-Toner particle A 100 parts-Hydrophobic silica A (RY200L manufactured by Nippon Aerosil Co., Ltd.) 1.2 parts-Zinc stearate fine particles A (D50: 6.0 um, 16 um or less,% by weight: 1.0% or less) 0.06 parts- Hydrotalcite fine particle A (Structural formula: Mg ₃ ZnAl ₂ (OH) ₁₂ CO ₃ .mH ₂ O, specific surface area: 6.5 m ² / g, average particle size 0.66 um) 0.1 part

<Example 2>
After obtaining negatively chargeable magnetic one-component toner particles with the same blending ratio as in Example 1, an external additive was mixed with a high-speed mixer at the following blending ratio to obtain Developer B.
・ Toner particles 100 parts ・ Hydrophobic silica A 1.2 parts ・ Zinc stearate fine particles A 0.06 parts ・ Hydrotalcite fine particles A 0.06 parts

<Comparative Example 1>
After obtaining negatively chargeable magnetic one-component toner particles with the same blending ratio as in Example 1, an external additive was mixed with a high-speed mixer at the following blending ratio to obtain developer C.
・ Toner particles 100 parts ・ Hydrophobic silica A 1.2 parts ・ Zinc stearate fine particles A 0.06 parts

<Comparative example 2>
A toner was prepared in the same manner as in Example 1 except that the magnetic powder of Example 1 was changed to the magnetic powder B to obtain toner particles B having a volume average particle size of 8.5 μm.
Magnetic powder B (spherical magnetite BET: 8.1 m ² / g, Hc: 90 Oe, σs: 86 Am ² / kg, σr: 9 Am ² / kg)
Toner particle B was subjected to the same external addition as in Example 1 to obtain developer D.

<Comparative Example 3>
A toner was prepared in the same manner as in Example 1 except that the magnetic powder of Example 1 was changed to magnetic powder C, and toner particles C having a volume average particle size of 8.5 μm were obtained.
Magnetic powder C (octahedral magnetite BET: 5.3 m ² / g, Hc: 118 Oe, σs: 83 Am ² / kg, σr: 10 Am ² / kg)
Toner particles C were subjected to the same external addition as in Example 1 to obtain developer E.
Table 1 shows the results of evaluating the above evaluation items for the toners produced in Examples 1 and 2 and Comparative Examples 1, 2 and 3.

1 Photosensitive drum (latent image forming medium)
2 Developer supply container
3 Development sleeve (developer carrier)
4 Toner layer thickness regulating member (developer regulating means)
5 Supply roller (developer supply means)
6 Toner
7 Stirring member

Claims (6)

  An electrostatic charge image developing toner used in an electrophotographic toner cartridge having a toner containing a magnetic material, a developing sleeve, and a toner layer thickness regulating member made of stainless steel for charging the toner on the developing sleeve, A toner for developing an electrostatic charge image, wherein the magnetic material has a hexahedral shape, and the toner has a hydrotalcite compound on a surface thereof.   2. The electrostatic image developing toner according to claim 1, wherein the toner layer regulating member is coated with silicon rubber.   3. The electrostatic charge image developing toner according to claim 1, wherein the developing sleeve is a Mo-treated aluminum base.   An electrophotographic toner cartridge having a toner containing a magnetic material, a developing sleeve, and a toner layer thickness regulating member for charging the toner on the developing sleeve, wherein the magnetic material has a hexahedral shape, and the toner is An electrophotographic toner cartridge comprising a hydrotalcite compound on a surface and the toner layer thickness regulating member made of stainless steel.   5. The electrophotographic toner cartridge according to claim 4, wherein the toner layer regulating member is covered with silicon rubber.   6. The electrophotographic toner cartridge according to claim 4, wherein the developing sleeve is a Mo-treated aluminum base.

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