JP2005091458A - Two-component developer and developing device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a two-component developer capable of sufficiently charging toner of the developer even when used in a high-speed image forming apparatus and to provide a developing device. <P>SOLUTION: In the two-component developer used in the developing device in which toner in a toner holding part is brought in a developer holding part according to the volume of a developer, magnetic carrier is a resin coated carrier comprising at least a magnetic core material and a resin, has a resin content of 5-25 mass%, an apparent density of 1.2-2.3 g/cm<SP>3</SP>and an average particle diameter of 25-55 μm, and includes 0.01-12 vol.% of particles of ≤21 μm and ≤1.0 vol.% of particles of ≥72 μm. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a developing device such as a copying machine, a printer, and a facsimile machine, and a two-component developer used in the developing device.

  2. Description of the Related Art Conventionally, in a developing device that performs development using a two-component developer using toner and a carrier, a developing device that takes in toner into the developer by the movement of the developer without requiring a toner density detecting means is known. Yes. However, in this developing device, the amount of toner taken in differs between a portion where the developer moves actively and a portion where the developer is not moving, or a portion where the developer is high and low, and the toner concentration is partially unstable. As a result, image density unevenness and fog were likely to occur.

  As a method for solving this problem, a developing sleeve that has a magnetic field generating means inside and carries and conveys a two-component developer containing toner and a magnetic carrier, and is carried and carried by the developing sleeve. A first regulating member that regulates the amount of the developer; a developer containing unit that contains the developer scraped off by the first regulating member; and a developer containing unit adjacent to the developer containing unit, on the developing sleeve A toner container for supplying the toner, and a change in the toner density of the developer on the developing sleeve changes the contact state between the developer and the toner, thereby taking in the toner in the developer on the developing sleeve Has been proposed (see, for example, Patent Document 1).

  Further, as a means for preventing the early deterioration of the two-component developer that occurs in the developing device, a developing device that promotes replacement of the developer on the developing sleeve and the developer in the developer accommodating portion has been proposed (for example, , See Patent Document 2 and Non-Patent Document 1).

However, in the above-described apparatus, if the developer amount is increased to achieve a longer life, the remaining developer moves rapidly except for the one passing through the gap between the developer pre-formed member and the developing sleeve. It becomes difficult to supply new toner to the developer that contributes to the development. Since the developer amount cannot be increased in this way, the replenished toner cannot be sufficiently charged, such as when a high-speed machine with a high image forming speed or printing with a high image area ratio is performed continuously. In some cases, toner scattering and fogging occurred.
JP-A-9-22178 (page 25, FIGS. 1 to 5) JP 2001-166580 A (page 6-11) Ricoh Technical Report No27 November, 2001, page 2-3

  The present invention has been made in view of the above problems, and its first object is to provide a two-component developer capable of sufficiently charging the toner of the developer even when used in a high-speed image forming apparatus. And a developing device.

  A second object of the present invention is to provide a two-component developer and a developing device that can sufficiently charge the toner of the developer even when a print image having a high image area ratio is continuously performed. .

  The third object is to optimize the developer capacity in the developer container so as to reduce the image density, increase the image density due to insufficient toner charging, cause scumming and toner scattering. It is an object of the present invention to provide a two-component developer and a developing device that can be prevented.

  A fourth object of the present invention is to provide a two-component developer and a developing device that can self-control the toner concentration of the developer without being influenced by the environment and can extend the life of the developer. .

In order to achieve the first object, in the two-component developer according to claim 1, the toner and the magnetic carrier in the developer containing portion are rotated while the developing sleeve having the magnetic field generating means is rotated inside. The developer containing the developer is transported while regulating the transport amount toward the developing region by the developer regulating member on the downstream side in the developer carrying direction of the developer accommodating portion, and the developer blocked by the developer regulating member. And a toner containing portion having a toner replenishing opening facing the surface of the developing sleeve at a position adjacent to the developer containing portion from the upstream side in the developer conveying direction, on the developing sleeve. A two-component developer used in a developing device that takes in the toner in the toner accommodating portion into the developer accommodating portion according to the developer capacity of the developer accommodating portion by the movement of the developer accompanying the developer conveyance of
The magnetic carrier is a resin-coated carrier having at least a magnetic core material and a resin,
The resin content is 5 to 25% by mass, the apparent density is 1.2 to 2.3 g / cm ³ , the average particle size is 25 to 55 μm, and 21 μm or less is 0.01 to 12% by volume. A two-component developer in which 15 μm or less is 3.0% by volume or less, 50 μm or more is 0.1 to 20% by volume, and 72 μm or more is 1.0% by volume or less. And
9. The developing device according to claim 8, wherein the developer containing the toner and the magnetic carrier in the developer accommodating portion is rotated in the developer conveying direction of the developer accommodating portion while rotating the developing sleeve having a magnetic field generating means therein. A developer containing member that restricts and conveys the developer amount toward the developing region by the developer restricting member on the downstream side, and contains the developer blocked by the developer restricting member, and the developer containing unit And a toner container having a toner replenishing opening facing the surface of the developing sleeve at a position adjacent from the upstream side in the developer conveying direction, and the developer is moved by the developer movement on the developing sleeve. A developing device that takes in the toner in the toner container into the developer container according to the capacity of the developer in the developer container;
The magnetic carrier constituting the developer is a resin-coated carrier having at least a magnetic core material and a resin,
The resin content is 5 to 25% by mass, the apparent density is 1.2 to 2.3 g / cm ³ , the average particle size is 25 to 55 μm, and 21 μm or less is 0.01 to 12% by volume. , 72 μm or more and 1.0% by volume or less of the developing device using the magnetic carrier.

  In order to achieve the second object, the two-component developer according to claim 3 is a magnetic fine particle dispersed resin carrier in which the magnetic core material has at least inorganic compound particles and a thermosetting phenol resin as a binder resin. It is characterized by being.

  In order to achieve the third object, in the two-component developer according to claim 4, the toner has a weight average particle diameter of 3.0 to 10.0 μm and contains 1 to 40% by mass of a solid wax. The developing device according to claim 9, wherein the developing device of the developer which is opposed to the surface of the developing sleeve in the developer accommodating portion in a non-contact manner and is carried and conveyed by the developing sleeve is provided. It has a peeling member for peeling off the upper layer portion.

  In order to achieve the fourth object, the two-component developer according to claim 5 is characterized in that the toner is a polymerized toner, and the developing device according to claim 10 includes the peeling member. Is characterized by using a magnetic material.

  According to the present invention, by controlling the particle size distribution of a low-density coat carrier having a resin content of 5 to 25% by mass within a specific range, the present invention can be applied to a simple development method that does not use a toner concentration detection means. In addition, toner deterioration and toner spent over a long period can be suppressed, and image stability can be achieved.

  Hereinafter, embodiments in which the present invention is applied to a developing device of an image forming apparatus such as a copying machine, a facsimile machine, and a printer will be described.

  FIG. 1 is a schematic configuration diagram of a main part of the printer according to the present embodiment. In FIG. 1, a developing device 2 disposed on the side of a photosensitive drum 1 serving as a latent image carrier is a support case 10, a developing sleeve 4, a developer containing member 11, and a first developer regulating member. It is mainly composed of the first doctor blade 6 and the like.

  A support case 10 having an opening on the side of the photosensitive drum 1 forms a toner hopper 8 as a toner storage portion for storing the toner 3a therein. Near the photosensitive drum 1 side of the toner hopper 8, a developer accommodating member 11 that accommodates a two-component developer 3 composed of toner 3a and a carrier 3b is provided integrally with the support case 10. Further, the support case 10 located below the developer containing member 11 is formed with a protruding portion 10a having a facing surface 10b, and the space between the lower portion of the developer containing member 11 and the facing surface 10b A toner supply opening 20 for supplying the toner 3a is formed.

  Inside the toner hopper 8, a toner agitator 9 is disposed as toner supply means that is rotated by a drive means (not shown). The toner agitator 9 sends out the toner 3a in the toner hopper 8 toward the toner supply opening 20 while stirring. Further, on the side of the toner hopper 8 facing the photosensitive drum 1, a toner end detection means 10c for detecting when the amount of the toner 3a in the toner hopper 8 decreases is disposed.

  A developing sleeve 4 is disposed in a space between the photosensitive drum 1 and the toner hopper 8. The developing sleeve 4 that is rotationally driven in the direction of the arrow in the figure by a driving means (not shown) has a magnet roller 5 as a magnetic field generating means disposed in a relative position unchanged with respect to the developing device 2. Yes.

  The first doctor blade 6 is integrally attached to the developer accommodating member 11 on the side facing the side attached to the support case 10. The first doctor blade 6 is disposed in a state where a certain gap is maintained between the tip of the first doctor blade 6 and the outer peripheral surface of the developing sleeve 4.

  A second doctor blade 7 as a second restricting member is disposed in a portion of the developer containing member 11 located in the vicinity of the toner supply opening 20. The second doctor blade 7 has a free end in a direction that obstructs the flow of the layer of the developer 3 formed on the surface of the developing sleeve 4 in order to keep a constant gap with respect to the outer peripheral surface of the developing sleeve 4, that is, free The base end is integrally attached to the developer accommodating member 11 with the end facing the center of the developing sleeve 4.

  The developer accommodating portion A is configured to have a sufficient space for circulating and moving the developer 3 within a range where the magnetic force of the magnet roller 5 in the developing sleeve 4 reaches.

  The facing surface 10b is formed over a predetermined length so as to incline downward from the toner hopper 8 side toward the developing sleeve 4 side. As a result, when vibration, uneven magnetic distribution of the magnet roller 5 provided inside the developing sleeve 4 or a partial increase in toner concentration in the developer 3 occurs, the second doctor blade 7 and the developing sleeve 4 Even if the carrier 3b in the developer accommodating portion A falls from between the peripheral surface of the toner, the dropped carrier 3b is received by the opposing surface 10b and moves to the developing sleeve 4 side, and is magnetically attached to the developing sleeve 4 by magnetic force. Then, it is supplied again into the developer accommodating portion A. As a result, it is possible to prevent a decrease in the amount of the carrier 3b in the developer accommodating portion A, and it is possible to prevent occurrence of uneven image density in the axial direction of the developing sleeve 4 during image formation.

  With the above configuration, the toner 3 a sent out from the inside of the toner hopper 8 by the toner agitator 9 is supplied to the developer 3 carried on the developing sleeve 4 through the toner supply opening 20 and is carried to the developer accommodating portion A. It is. The developer 3 in the developer accommodating portion A is carried on the developing sleeve 4 and conveyed to a position facing the outer peripheral surface of the photosensitive drum 1, and only the toner 3 a is formed on the photosensitive drum 1. A toner image is formed on the photosensitive drum 1 by electrostatic coupling with the electrostatic latent image.

  Next, when the toner 3 a is set in the toner hopper 8, the toner 3 a is supplied from the toner supply opening 20 to the magnetic carrier 3 b carried on the developing sleeve 4. Therefore, the developing sleeve 4 carries the developer 3 that is a mixture of the toner 3a and the magnetic carrier 3b.

  In the developer accommodating portion A, when the capacity of the developer 3 accommodated in accordance with the toner concentration increases or decreases and the toner concentration decreases (the image density decreases), the developer capacity in the developer accommodating portion A Decreases, more toner 3a is sent to the developer accommodating portion through the toner supply opening 20, and the toner density increases. On the other hand, when the toner density increases (the image density increases), the developer capacity in the developer accommodating portion A increases, and the developer overflows to the toner supply opening 20, and the toner 3a becomes the developer. Since the toner is prevented from being sent to the container, the toner density is lowered.

  As described above, the toner concentration in the developer accommodating portion changes according to the toner concentration, so that the toner concentration in the developer accommodating portion can be kept within a certain range. As described above, according to the developing device of the present embodiment, it is possible to perform self-control of the toner concentration of the developer without requiring a conventional toner replenishing mechanism and a toner concentration sensor.

  Next, the carrier and toner constituting the developer used in the developing device of the present embodiment will be described.

  We have investigated the spent property of the toner and external additives to the carrier in durability with a small amount of developer. As for the physical properties of the carrier, those having a larger particle size and a larger apparent density are those of the toner and the external additive. It was found that the spent property of the additive is high. The reason for this is that when the apparent density is large, the compression of the developer in the developing device becomes strong, the spent property increases, and when the particle size is large, the contact opportunity with the toner in the developing device increases. It is thought that the spent property increases.

  On the other hand, in order to faithfully reproduce the latent image, a toner having a smaller particle diameter must be uniformly charged, so that the contact opportunity between the toner and the carrier is increased and the spent property is increased. That is, satisfying the above-mentioned conflicting carrier characteristics can provide a two-component developer having high image quality and excellent durability.

From this point of view, we have intensively studied and found that the above problems can be solved by well controlling the particle size distribution and the apparent density of the carrier. That is, the resin-coated carrier used has a resin content of 5 to 25% by mass, an apparent density of 1.2 to 2.3 g / cm ³ , preferably 1.6 to 2.0 g / cm ³ , and an average The particle size is 25 to 55 μm, preferably 30 to 50 μm, 21 μm or less is 0.01 to 12% by volume, preferably 0.03 to 6.0%, and 72 μm or more is 1.0% by volume or less, preferably Is to satisfy the structure satisfying 0.5% by volume or less.

  The resin-coated carrier has an average particle diameter of 25 to 55 μm so that the present invention is suitably expressed. When it is larger than 55 μm, it becomes insufficient to give a uniform and good charge to the toner with a small amount of developer, which causes fogging and toner scattering. On the other hand, when the particle size is smaller than 25 μm, the fluidity of the developer tends to be deteriorated, and the developer capacity does not show an expected fluctuation depending on the toner concentration, and as a result, the self-controllability of the toner concentration is likely to be impaired. .

  In addition, when the abundance on the fine particle side is large, not only the fluidity of the developer is deteriorated, the coating is likely to be non-uniform and image density unevenness is likely to occur, but also an electrostatic latent image is formed via a carrier. It becomes easy to disturb. On the contrary, when the abundance on the fine particle side is small, the flowability of the developer is good, but it becomes insufficient to give the toner uniform and good charge, and it is difficult to faithfully reproduce the latent image. In addition, it causes fogging and toner scattering.

  As described above, iron powder, ferrite, and magnetite are used as the carrier ferromagnetic material in the present invention, and ferrite or magnetite is preferable. Since the iron powder carrier has a large saturation magnetization, it becomes easy to toner spend, and is not particularly preferable in the present invention.

An apparent density of 1.2 to 2.3 g / cm ³ is required to suppress toner deterioration with durability, which is one of the objects of the present invention, and in order to suppress carrier adhesion to the photoreceptor. The apparent density is preferably 1.5 to 2.0 g / cm ³ .

In the present invention, examples of the ferromagnetic material that can be suitably used include magnetite and ferrite having magnetism represented by the following formula (1) or (2).
MO · Fe ₂ O ₃ (1)
M · Fe ₂ O ₄ (2)
(In the formula, M represents a trivalent, divalent or monovalent metal ion.)
Examples of M include Be, Mg, Ca, Rb, Sr, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Y, Zr, Nb, Mo, Cd, Pb, and Li. It can be used alone or in plural.

  In the present invention, Li, Be, Mg, K. Light metals composed of Ca, Sr and Rb can be mentioned, and these are preferably used singly or in a plurality so that the specific gravity and density can be easily controlled, but they can be used in combination with other metals such as Mn and K. You may adjust with content.

  Specific examples of the metal compound particles having magnetism include Ca—Mg—Fe ferrite, Li—Fe ferrite, Mn—Mg—Fe ferrite, Ca—Be—Fe ferrite, and Mn—Mg. Examples thereof include iron-based oxides such as -Sr-Fe-based ferrite, Li-Mg-Fe-based ferrite, and Li-Rb-Fe-based ferrite.

In particular, the ratio of one or more oxides selected from the group consisting of Li, Be, Mg, Ca and Sr to Fe ₂ O ₃ in the ferrite component is 5:95 to 55:45, preferably in mol%. The range of 35:65 to 55:45 is suitable. When the ratio is out of the range, the surface state is difficult to control as described later, and it may be difficult to carry 5 to 25% by mass of the resin.

It is desirable to add a small amount of other metal oxides to the ferrite particles for the core material in order to control the degree of crystal growth and unevenness on the particle surface or to control the particle density. Other metal oxides are one or more oxides belonging to groups IA, IIA, IIIA, IVA, VA, IIIB and VB of the periodic table, such as BaO, Al ₂ O ₃ , TiO ₂ , SiO _2. , SnO ₂ and Bi ₂ O ₅ .

  Further, conventionally known heavy metal oxides such as Cu0 and Zn0 may be added as a charge accelerator.

  The amount of the other metal oxide added is preferably 0.01 to 10 parts by mass, preferably 0.05 to 5 parts in total with respect to 100 parts by mass of the ferrite component. When the addition amount is less than 0.01 parts by mass, crystal growth tends to be low, and the particle strength tends to be low. On the other hand, when the amount exceeds 10 parts by mass, the uniformity of the composition is lost, and the production of oxides other than the ferrite composition and the production of non-magnetic or weak magnetic materials due to the reaction between the oxide and hematite are likely to occur. As a result, there is a disadvantage that carrier adhesion to the photoreceptor occurs.

  In the present invention, in order to satisfy the above-mentioned apparent density, the resin content is desirably 5 to 25% by mass, preferably 8 to 17% by mass.

  Next, a spherical magnetic fine particle dispersed resin carrier (hereinafter referred to as “resin carrier”) particularly preferably used in the present invention will be described in detail.

  The resin carrier of the present invention is preferably formed of a carrier core in which inorganic compound particles are dispersed in a binder resin, and the particle surface of the carrier core is preferably treated.

  The inorganic compound particles constituting the carrier core in the present invention may be any inorganic compound particles that do not dissolve in water or are not altered or denatured by water, and include those obtained by mixing magnetic inorganic compound particles and nonmagnetic inorganic compound particles.

  Examples of magnetic inorganic compound particles include magnetite particles, maghemite particles, particles obtained by depositing or containing cobalt therein, barium, strontium or barium-strontium-containing magnetoplumbite type ferrite particles, manganese, nickel, zinc, Various magnetic particles such as spinel ferrite particles containing one or more selected from lithium and magnesium can be used.

  Nonmagnetic inorganic compound particles include hematite particles, hydrous ferric oxide particles, titanium oxide particles, silica particles, talc particles, alumina particles, barium sulfate particles, barium carbonate particles, cadmium yellow particles, calcium carbonate particles, zinc white particles. Etc. can be used.

  As the particle form of the inorganic compound particles, particles having any form such as cubic, polyhedral, spherical, needle-like, and plate-like can be used. The 50% particle size of the inorganic compound particles may be any particle that is smaller than the 50% particle size of the magnetic carrier, and is preferably 0.02 to 5.0 μm. In particular, the 50% particle size of the magnetic inorganic compound particles is (a). When the 50% particle size of the nonmagnetic inorganic compound particles is (b), (a) is 0.02 to 2 μm, (b) is 0.05 to 5 μm, and 1.5 (a) <(B) is more preferable.

Further, the nonmagnetic inorganic compound particles have a larger volume resistance value than the magnetic inorganic compound particles, and the 50% particle size of the nonmagnetic inorganic compound particles is larger than the 50% particle size of the magnetic inorganic compound particles. It is preferable for increasing the resistance value and reducing the true specific gravity of the carrier. In particular, the nonmagnetic inorganic compound particles are preferably 10 ⁷ Ωcm or more, more preferably 10 ⁸ to 10 ¹⁴ Ωcm, from the viewpoint that the resistance of the magnetic carrier can be adjusted.

  The magnetic inorganic compound particles are contained in an amount of 30 to 95% by mass with respect to the total amount of the magnetic inorganic compound particles and the nonmagnetic inorganic compound particles, thereby adjusting the magnetic force of the carrier to prevent carrier adhesion. It is preferable for adjusting the volume resistance value.

  It is also preferred that the inorganic compound particles are all or partly treated with a lipophilic agent. As the lipophilic agent, an organic compound having one or more functional groups selected from an epoxy group, amino group, mercapto group, organic acid group, ester group, ketone group, halogenated alkyl group and aldehyde group A compound or a mixture thereof can be used, and any of them can achieve the object of the present invention. Among these, a coupling agent having the above functional group is preferable, and a silane coupling agent is particularly preferable. Furthermore, as a preferable functional group, an epoxy group, an amino group, and a mercapto group are preferable in that the particle size distribution of the carrier is sharp, and further, the epoxy group makes the dispersed state of the inorganic compound particles uniform, and the temperature and humidity This is preferable in that the charge imparting ability of the carrier is stable.

  As the binder resin constituting the carrier core in the present invention, a thermosetting resin is particularly preferable.

  Thermosetting resins include phenolic resins, epoxy resins, polyamide resins, melamine resins, urea resins, unsaturated polyester resins, alkyd resins, xylene resins, acetoguanamine resins, furan resins, silicone resins, polyimide resins, urethane resins. These resins may be used alone or in combination of two or more, but preferably contain at least a phenol resin.

  The surface of the carrier core used in the magnetic carrier of the present invention may be coated with a coupling agent or resin as necessary.

  The resin used for coating may be any resin as long as it is a common resin, and examples thereof include epoxy resins, silicone resins, polyester resins, fluororesins, styrene resins, acrylic resins, and phenol resins. A polymer obtained by polymerization from monomers may also be used. In view of durability and stain resistance, silicone resin is preferable.

  The coating amount of the resin covering the carrier core is preferably 0.05% by mass or more with respect to the carrier core. When the amount is less than 0.05% by mass, an insufficient and non-uniform film tends to be formed, and it becomes difficult to freely control the charge amount. On the other hand, if the coating amount is too large, the electric resistance of the magnetic carrier tends to be too high, causing problems on the image. More preferably, it is 0.1-10 mass%, More preferably, it is 0.2-5 mass% in order to prevent unity of the particles at the time of resin coating.

  If necessary, the resin covering the carrier core may contain a coupling agent in an amount of 0.1 to 20.0% by mass based on the resin solid content. As the coupling agent, a silane coupling agent is preferable. More preferably, the content is 0.1 to 10.0% by mass in order to prevent strength reduction due to self-condensation of the coupling agent.

  Moreover, when coat | covering a carrier core with a coupling agent, 0.001-0.5 mass% is preferable with respect to a carrier core. In this case, the coupling agent includes one or more functional groups selected from an epoxy group, amino group, mercapto group, organic acid group, ester group, ketone group, halogen group, alkyl group and aldehyde group. A coupling agent having, particularly preferably, a silane coupling agent can be used.

  As a more preferable form of the resin carrier, a phenol resin is used as the binder resin of the carrier core, an epoxy group-containing silane coupling agent is used as the surface treatment agent of the inorganic compound particles, and it is contained in the silicone coat resin covering the carrier core. A thing using the silane coupling agent which has an amino group as a thing or a pre-processing material of a carrier core is mentioned. By doing so, the moisture adsorbed moderately in the binder resin causes the silane coupling agent containing amino groups to hydrolyze and self-condensate while hydrogen bonding with the hydroxyl groups of the phenol resin, or Condensation with the remaining silanol groups in the silicone resin to form a strong coating, and at the same time, the amino groups react with the epoxy groups of the surface treatment agent of the inorganic compound particles, improving the adhesion of the silicone resin, missing the coating resin, etc. Is suppressed.

  In order to make the physical properties of the resin carrier fall within a predetermined range, it is preferable to add nonmagnetic inorganic compound particles to the carrier core in addition to the magnetic inorganic compound particles. Adjustment of the specific gravity of the carrier is that the total amount of the magnetic inorganic compound particles and the nonmagnetic inorganic compound particles is 70 to 99% by mass in the magnetic carrier, more preferably 80 to 99% by mass. And the relationship between the adjustment of the particle size distribution of the carrier and the mechanical strength of the carrier core.

  The shape of the resin carrier is appropriately selected so as to be convenient for a predetermined system. However, the resin carrier is more preferably spherical. If the resin carrier is not spherical, the fluidity of the developer will be inferior, and if a small amount of developer is used, the ability to impart triboelectric charge to the toner will be reduced and the shape of the magnetic brush will become uneven at the development pole. It is difficult to obtain high quality images.

  Next, the suitable manufacturing method of the resin carrier based on this invention is described.

  The treatment with the lipophilic agent for the inorganic compound particles may be performed by adding and mixing a solution of a coupling agent or an organic compound to the inorganic compound particles.

  The carrier core is a so-called polymerization method in which inorganic compound particles dispersed in a solvent are dispersed in a monomer constituting the binder resin, and an initiator or a catalyst is added, or a binder resin containing inorganic compound particles. The so-called kneading and pulverizing method can be used, but a polymerization method is preferable in order to easily control the particle size of the resin carrier and to obtain a sharp particle size distribution. That is, the carrier core produced by the polymerization method can be arbitrarily controlled by the reaction conditions during the polymerization, for example, the catalyst addition conditions, the polymerization temperature conditions, the stirring conditions of the solvent dispersion, and the like. Unlike the case where it carries out, even if it does not pass through a classification process, since it can achieve a sharp particle size distribution with a fine particle size of 25-55 μm and no fine powder, it is preferable.

  The production of a carrier core by a polymerization method using a phenol resin as a binder resin preferably used in the present invention is performed by, for example, dispersing inorganic compound particles subjected to lipophilic treatment with phenols and aldehydes in an aqueous medium. And a method in which a basic catalyst is added to cause a polymerization reaction. A method of forming a so-called modified phenol resin in which a natural resin such as rosin and a dry oil such as paulownia oil or linseed oil are mixed and reacted together with phenols can also be mentioned.

  In particular, when the binder resin is a phenol resin, an appropriate amount of adsorbed water is retained, which is preferable in order to promote hydrolysis of the coupling agent and form a strong coating.

  As another condition, the production of a carrier core using an epoxy resin as a binder resin can be performed, for example, by dispersing bisphenols, epihalohydrin, and lipophilic inorganic compound particles in an aqueous medium, and polymerizing in an alkaline aqueous medium. The method of making it react is mentioned.

  As yet another condition, the production of a carrier core using a melamine resin as a binder resin can be achieved by, for example, dispersing melamines and aldehydes in an aqueous medium and inorganic compound particles subjected to oleophilic treatment to form a weakly acidic catalyst. And a polymerization reaction in the presence of.

  Examples of the carrier core manufacturing method using other binder resins include, for example, kneading inorganic compound particles that have been subjected to lipophilic treatment with various resins, pulverizing, classifying as necessary, and further spheroidizing The method of performing a process etc. are mentioned.

  The carrier core composed of the inorganic compound particles subjected to the oleophilic treatment and the binder resin is subjected to heat treatment as necessary in order to further cure the resin. It is particularly preferable to carry out under reduced pressure or in an inert atmosphere in order to prevent oxidation of inorganic compound particles and the like.

  The coating treatment of the carrier core with the coupling agent is carried out by immersing the carrier core in a solution obtained by dissolving the coupling agent in water or a solvent by a conventional method, followed by filtration and drying, or the coupling agent while stirring the carrier core. A method of spraying and drying an aqueous solution or a solvent solution is used. In particular, in order to prevent the carrier cores from being united and to form a uniform coating layer, a method of treating with stirring is preferred.

  The coating of the resin may be performed by a known method, for example, a method of dry-mixing the carrier core and the resin using a Hellshell mixer, a high speed mixer or the like, a method of impregnating the carrier core in a solvent containing the resin Any of the methods of spraying resin on the carrier core using a spray dryer may be used.

  In addition, a method in which a carrier core is reacted with phenols, aldehydes, or melamines and aldehydes in an aqueous medium to coat the phenol resin or melamine resin, or a mixture of acrylonitrile and other vinyl monomers in an aqueous medium. A method of coating with acrylonitrile and polymerizing with acrylonitrile, or a method of coating with polyamide resin by anionic polymerization of lactams may be used.

(Measurement method of carrier characteristic value)
Here, a method of measuring characteristic values used for the carrier of the present invention will be described. In addition, it measured similarly also in the Example mentioned later.

  (1) The 50% particle size of the carrier, carrier core, and inorganic compound particles is a value measured by a laser diffraction particle size distribution meter (manufactured by Horiba, Ltd.). A specific measurement method is as follows.

  Using a Microtrac particle size analyzer (manufactured by Nikkiso Co., Ltd.), the carrier and carrier core are measured with a range setting of 7 to 700 μm, and the inorganic compound particles are measured with a range setting of 0.0032 to 6.5406 μm. To obtain a 50% particle size.

  (2) Measurement of apparent density: The apparent density is measured using a powder tester (manufactured by Hosokawa Micron). As a measurement, a 100 mesh (140 μm mesh) sieve is set on a vibration table, and an apparent density measuring cup (internal capacity 100 cc) whose weight has been measured in advance is placed immediately below.

  Next, the rheostat scale is set to 2.0 and vibration is started. A measurement sample is gently allowed to flow out of the vibrating 100 mesh sieve so as to enter the measurement cup.

  When the cup is filled with the heaped sample, the vibration is stopped, and the upper surface of the heaped cup is ground with a blade and accurately weighed with a balance.

Since the measuring cup has an internal capacity of 100 cc, the apparent density (g / cm ³ ) = the weight of the sample ÷ 100.

  The sample used was left for about 12 hours in an environment of 23 ° C. and 60% RH, and the measurement environment was 23 ° C. and 60% RH.

  When measuring the carrier physical properties from the developer, the developer is washed with ion-exchanged water containing 1% of Contaminone N (surfactant) to separate the toner and the carrier, and then the above measurement is performed.

<2> Developer in the Present Invention Next, a preferable embodiment of the toner used in the developer of the present invention will be described.

  The toner according to the present invention preferably has a weight average particle diameter of 3.0 to 10.0 [mu] m, and particularly preferably 4.5 to 9.5 [mu] m.

  When the weight average particle diameter (D4) of the toner exceeds 10.0 μm, the toner particles for developing the electrostatic latent image become large. Therefore, even if the magnetic force of the carrier is lowered, development faithful to the electrostatic latent image is performed. In addition, the toner is likely to be scattered when electrostatic transfer is performed. In addition, a toner having a weight average particle size of less than 3.0 μm has a reduced handling property as a powder, and at the same time, a miscibility with a carrier is not uniform, toner charging cannot be performed well, and a toner tribo distribution is wide. Therefore, problems such as a change in particle diameter due to durability are likely to occur due to poor charging (generation of reversal component) and uneven distribution of the developed toner particle diameter.

  The toner used in the present invention preferably has an average circularity of 0.945 to 0.995 in the circularity distribution of the particles measured by a flow particle analyzer. A more preferable average circularity is 0.955 to 0.995.

  If the average circularity is less than 0.945, the transfer efficiency is lowered, and if it exceeds 0.995, it tends to be difficult to clean the toner on the photosensitive drum, the intermediate transfer member, or the transfer conveyance belt. It is not preferable.

The average circularity in the present invention is used as an index for quantitatively expressing the shape of particles, and in the present invention, measurement is performed using a flow type particle image analyzer “FPIA-1000” manufactured by Toa Medical Electronics, A value obtained by calculating the circularity (ai) of the measured particle by the following formula (2), and further dividing the total roundness of all the particles measured by the following formula (3) by the total number of particles (m). Is defined as the average circularity (am).
Circularity (ai) = L0 / L Formula (2)
(In the formula, L0 represents the circumference of a circle having the same projected area as the toner particle image, and L represents the circumference of the projected image of toner particles.)

  In addition, "FPIA-1000" which is a measuring apparatus used in the present invention calculates the circularity of each particle, and then calculates the average circularity, and the circularity of 0.40 to 1.. A calculation method is used in which 00 is divided into 61 classes, and the average circularity is calculated using the center value and frequency of the division points. However, there is very little error between each value of the average circularity calculated by this calculation method and each value of the average circularity calculated by the above-described calculation formula that directly uses the circularity of each particle. In the present invention, the calculation formula directly using the circularity of each particle described above is used for reasons of data handling such as shortening the calculation time and simplifying the calculation formula. Such a calculation method that is partially changed using the concept may be used.

  The measurement procedure is as follows.

  A dispersion is prepared by dispersing about 5 mg of magnetic toner in 10 ml of water in which about 0.1 mg of a surfactant is dissolved, and the dispersion is irradiated with ultrasonic waves (20 kHz, 50 W) for 5 minutes. Measurement is performed with the above apparatus at 5000 to 20,000 / μl, and the average circularity and mode circularity of a particle group having a circle-equivalent diameter of 3 μm or more are obtained.

  The average circularity in the present invention is an index of the degree of unevenness of the toner, and indicates 1.000 when the toner is a perfect sphere, and the average circularity becomes smaller as the toner surface shape becomes more complicated.

  As the binder resin used for the toner, the following binder resins can be used.

  For example, styrene such as polystyrene, poly-p-chlorostyrene, and polyvinyltoluene, and homopolymers of substituted styrene; styrene-p-chlorostyrene copolymer, styrene-vinyltoluene copolymer, styrene-vinylnaphthalene copolymer , Styrene-acrylic acid ester copolymer, styrene-methacrylic acid ester copolymer, styrene-α-chloromethyl methacrylate copolymer, styrene-acrylonitrile copolymer, styrene-vinyl methyl ether copolymer, styrene-vinyl Styrene copolymers such as ethyl ether copolymer, styrene-vinyl methyl ketone copolymer, styrene-butadiene copolymer, styrene-isoprene copolymer, styrene-acrylonitrile-indene copolymer; polyvinyl chloride; phenol Resin; Naturally modified Natural resin modified maleic acid resin; acrylic resin; methacrylic resin; polyvinyl acetate; silicone resin; polyester resin; polyurethane; polyamide resin; furan resin; Petroleum-based resins can be used. Preferable binder resins include styrene copolymers or polyester resins. A cross-linked styrene resin is also a preferable binder resin.

  The styrenic polymer or styrenic copolymer may be cross-linked, or may be a mixed resin of a cross-linked resin and a non-cross-linked resin.

  As the crosslinking agent for the binder resin, a compound having two or more polymerizable double bonds may be mainly used. For example, aromatic divinyl compounds such as divinylbenzene and divinylnaphthalene; carboxylic acid esters having two double bonds such as ethylene glycol diacrylate, ethylene glycol dimethacrylate, and 1,3-butanediol dimethacrylate; divinylaniline; And divinyl compounds such as divinyl ether, divinyl sulfide and divinyl sulfone; and compounds having three or more vinyl groups. These are used alone or as a mixture.

  As addition amount of a crosslinking agent, 0.001-10 mass parts is preferable with respect to 100 mass parts of polymerizable monomers.

  The toner may contain a charge control agent.

  The following substances are used for controlling the toner to be negatively charged. For example, organometallic compounds and chelate compounds are effective, and monoazo metal compounds, acetylacetone metal compounds, aromatic hydroxycarboxylic acids, and aromatic dicarboxylic acid metal compounds are preferably used. Further, aromatic hydroxycarboxylic acids, aromatic mono- and polycarboxylic acids and their metal salts, their anhydrides, their esters, their phenol derivatives such as bisphenol; urea derivatives; metal-containing salicylic acid compounds; Metallic naphthoic acid compounds; boron compounds; quaternary ammonium salts; calixarene; silicon compounds; styrene-acrylic acid copolymers; styrene-methacrylic acid copolymers; styrene-acrylic-sulfonic acid copolymers; and nonmetal carboxylic acid systems Compounds.

  The following substances are used to control the toner to be positively charged.

  Modified products with nigrosine and fatty acid metal salts, quaternary ammonium salts such as guanidine compounds, imidazole compounds, tributylbenzylammonium-1-hydroxy-4-naphthosulfonate, tetrabutylammonium tetrafluoroborate, and analogs thereof Some onium salts such as phosphonium salts and their lake pigments, triphenylmethane dyes and these lake pigments (as rake agents, phosphotungstic acid, phosphomolybdic acid, phosphotungsten molybdic acid, tannic acid, lauric acid, gallic acid) Acids, ferricyanides, ferrocyanides, etc.), metal salts of higher fatty acids; diorganotin oxides such as dibutyltin oxide, dioctyltin oxide, dicyclohexyltin oxide; dibutyltin borate, Octyl tin borate, diorgano tin borate such as dicyclohexyl tin borate; can be used in combination singly, or two or more kinds. Among these, a charge control agent such as a nigrosine-type quaternary ammonium salt is particularly preferably used.

  These charge control agents may be used in an amount of 0.01 to 20 parts by weight, preferably 0.1 to 10 parts by weight, more preferably 0.2 to 4 parts by weight, based on 100 parts by weight of the resin component of the toner. .

  As the colorant of the toner used in the present invention, a black colorant prepared by using carbon black, a magnetic material, and the following yellow / magenta / cyan colorant is used.

  As the yellow colorant, compounds represented by condensed azo compounds, isoindolinone compounds, anthraquinone compounds, azo metal complexes, methine compounds, and allylamide compounds are used. Specifically, C.I. I. Pigment Yellow 12, 13, 14, 15, 17, 62, 74, 83, 93, 94, 95, 109, 110, 111, 128, 129, 147, 168 or 180 are preferably used. Furthermore, C.I. I. You may use together dyes, such as Solvent Yellow 93 and 162.

  As the magenta colorant, condensed azo compounds, diketopyrrolopyrrole compounds, anthraquinones, quinacridone compounds, basic dye lake compounds, naphthol compounds, benzimidazolone compounds, thioindigo compounds, and perylene compounds are used. Specifically, C.I. I. Pigment Red 2, 3, 5, 6, 7, 23, 48: 2, 48: 3, 48: 4, 57: 1, 81: 1, 144, 146, 166, 169, 177, 184, 185, 202 , 206, 220, 221 or 254 are preferably used.

  As the cyan colorant, copper phthalocyanine compounds and derivatives thereof, anthraquinone compounds, basic dye lake compounds, and the like can be used. Specifically, C.I. I. Pigment Blue 1, 7, 15, 15: 1, 15: 2, 15: 3, 15: 4, 60, 62, 66 can be used particularly preferably.

  These colorants can be used alone or mixed and further in a solid solution state. The colorant of the present invention is selected from the viewpoints of hue angle, saturation, brightness, weather resistance, OHP transparency, and dispersibility in the toner. The colorant is added in an amount of 1 to 20 parts by mass with respect to 100 parts by mass of the resin.

  It is preferable that the toner particles contain 1 to 40% by mass, preferably 2 to 20% by mass of solid wax. If the wax is less than 1% by mass, the effect of suppressing the offset is small, and if it exceeds 40% by mass, the toner surface is unevenly distributed, and sleeve contamination is likely to occur, resulting in an uneven amount of developer on the developing sleeve. It is easy to change the image density. As a preferred wax, the toner has excellent fluidity by using a wax having a weight average molecular weight (Mw) / number average molecular weight (Mn) of 1.45 or less in the molecular weight distribution measured by gel permeation chromatography (GPC). A uniform fixed image with no gloss unevenness can be obtained. Further, contamination of the heating member of the fixing device and deterioration of storage stability are difficult to occur, and the fixing property and light transmittance of the fixed image are excellent. In addition to being able to create a full color OHP and exhibit good low-temperature fixability without partly offsetting the toner, a part or all of the wax coats the heating member appropriately when producing a full color OHP excellent in Thus, the life of the pressure contact member can be extended.

  The wax contained in the toner used in the present invention has a weight average molecular weight (Mw) / number average molecular weight (Mn) of 1.45 or less, preferably 1.30 or less in GPC molecular weight distribution using a double column. It is more preferable in terms of uniformity of the fixed image, good transferability of the toner, and prevention of contamination of the contact charging means for charging in contact with the photoreceptor.

  When the value of Mw / Mn of the wax exceeds 1.45, the fluidity of the toner is lowered, so that uneven glossiness of the fixed image is likely to occur. Further, the transferability of the toner is lowered and the contact charging means is contaminated. Is likely to occur.

  In the present invention, the molecular weight distribution of the wax is measured by GPC using a double column under the following conditions.

(GPC measurement conditions)
Apparatus: GPC-150C (manufactured by Waters)
Column: GMH-HT 30 cm 2 series (manufactured by Tosoh Corporation)
Temperature: 135 ° C
Solvent: o-dichlorobenzene (0.1% ionol added)
Flow rate: 1.0 ml / min
Sample: 0.4 ml injection of 0.15% concentration sample. The molecular weight calibration curve prepared with a monodisperse polyurethane standard sample is used for calculating the molecular weight of the sample. Furthermore, a weight average molecular weight and a number average molecular weight are calculated by converting to polyethylene using a conversion formula derived from the Mark-Houwink viscosity formula.

  The melting point of the wax used in the present invention is preferably 40 to 150 ° C, more preferably 50 to 120 ° C. When the melting point of the wax is lower than 40 ° C., the toner is resistant to blocking, and the sleeve is liable to be contaminated when copying a large number of sheets. When the image forming speed is changed, the coating of the developer becomes uneven and uneven image density occurs. Cheap. When the melting point of the wax exceeds 150 ° C., excessive energy is required for uniform mixing with the binder resin in the toner production method by the pulverization method, and even in the toner production method by the polymerization method For this reason, there is a limit to the size of the apparatus by increasing the viscosity or the amount of compatibility, which makes it difficult to contain a large amount.

  The melting point of the wax is the temperature at the main peak value in the endothermic curve measured according to ASTM D3418-8.

  For the measurement according to ASTM D3418-8, for example, DSC-7 manufactured by Perkin Elmer is used. The temperature correction of the device detection unit uses the melting point of indium zinc, and the correction of heat uses the heat of fusion of indium. As the sample, an aluminum pan is used, an empty pan is set for control, and measurement is performed at a temperature rising rate of 10 ° C./min in a temperature range of 20 to 200 ° C.

  Further, the wax used in the present invention has a molecular weight distribution measured by GPC having two or more peaks or one or more peaks and one or more shoulders, and in the molecular weight distribution, the weight average molecular weight ( Mw) is preferably 200 to 2,000, and the number average molecular weight (Mn) is preferably 150 to 2,000. The molecular weight distribution described above may be achieved with either a single wax or a plurality of waxes, and as a result, it has been found that crystallinity can be hindered and transparency is further improved. The method of blending two or more kinds of waxes is not particularly limited. For example, a media type disperser (ball mill, sand mill, attritor, apex mill, coball mill, handy mill) is used above the melting point of the wax to be blended. It is also possible to melt and blend, or to dissolve the wax to be blended into a polymerizable monomer and blend it with a media type disperser. At this time, pigments, charge control agents, and polymerization initiators may be used as additives.

  The wax preferably has a weight average molecular weight (Mw) of 200 to 2000 and a number average molecular weight (Mn) of 150 to 200. More preferably, it is good that Mw is 200-1500, More preferably, it is 300-1000, Mn is 200-1500, More preferably, it is 250-1000. When the Mw of the wax is less than 200 and the Mn is less than 150, the blocking resistance of the toner may be lowered. When the Mw of the wax exceeds 2000 and the Mn exceeds 2000, the crystallinity of the wax itself is developed and the transparency may be lowered.

  Examples of waxes that can be used in the present invention include paraffin waxes, polyolefin waxes, modified products thereof (for example, oxides and grafted products), higher fatty acids, and metal salts thereof, amide waxes, and ester systems. Wax etc. are mentioned.

  Among these, ester wax is particularly preferable in that a higher-quality full-color OHP image can be obtained.

  As a method for producing an ester wax preferably used in the present invention, for example, a synthesis method by an oxidation reaction, a synthesis from a carboxylic acid and a derivative thereof, and an ester group introduction reaction represented by a Michael addition reaction are used.

  Next, a method for producing the toner used in the present invention will be described. The toner used in the present invention can be manufactured using a pulverized toner manufacturing method and a polymerized toner manufacturing method.

  As a method for producing the polymerized toner, there are disclosed a method for obtaining a spherical toner by atomizing a molten mixture in air using a disk or other fluid nozzle described in JP-B-56-13945, JP-B-36-10231, JP A method of directly producing toner using the suspension polymerization method described in JP-A-59-53856 and JP-A-59-61842, or a monomer that is soluble and insoluble in a monomer. An emulsion polymerization method represented by a dispersion polymerization method that directly produces a toner using an aqueous organic solvent or a soap-free polymerization method that produces a toner by directly polymerizing in the presence of a water-soluble polar polymerization initiator, After the production, the toner can be produced using a hetero-aggregation method in which polar particles having opposite charges are added and associated.

  Among these, polymerized toner particles obtained by a method of directly polymerizing a monomer composition containing at least a polymerizable monomer, a colorant and a wax to produce toner particles are preferable.

  In the present invention, a suspension polymerization method under normal pressure or under pressure, in which a fine particle toner having a sharp particle size distribution can be obtained relatively easily, is particularly preferred. A so-called seed polymerization method in which a monomer is further adsorbed to the polymer particles once obtained and then polymerized using a polymerization initiator can also be suitably used in the present invention.

  As a preferable form of the toner used in the present invention, wax is encapsulated in an outer shell resin layer by a tomographic surface measurement method of the toner using a transmission electron microscope (TEM). From the viewpoint of fixing properties, it is necessary to include a large amount of wax in the toner, so that the wax is encapsulated in the outer shell resin layer from the viewpoint of the storage stability and fluidity of the toner. When the toner is not encapsulated, the wax cannot be uniformly dispersed, and as a result, the particle size distribution becomes wide and toner fusion to the mounting is likely to occur.

  As a specific method for embedding the wax, the polarity of the material in the aqueous medium is set to be smaller than that of the main monomer, and a small amount of a large polarity resin or monomer is added. A toner having a so-called core-shell structure in which wax is coated with an outer shell resin can be obtained. Toner particle size distribution control and particle size control can be achieved by changing the type and amount of a poorly water-soluble inorganic salt or dispersant that acts as a protective colloid, as well as mechanical equipment conditions such as rotor peripheral speed, number of baths, and stirring. A predetermined toner of the present invention can be obtained by controlling stirring conditions such as blade shape, container shape, solid content concentration in an aqueous solution, and the like.

  When the direct polymerization method is used in the toner manufacturing method of the present invention, the toner can be specifically manufactured by the following manufacturing method. Add monomer, wax, colorant, charge control agent, polymerization initiator and other additives to the monomer, and uniformly dissolve or disperse the monomer composition with a homogenizer, ultrasonic disperser, etc. The aqueous phase is dispersed with a normal stirrer or a stirrer such as a homomixer or a homogenizer. Preferably, granulation is performed by adjusting the stirring speed and time so that the droplets of the monomer composition have a desired toner particle size. Thereafter, stirring may be performed to such an extent that the particle state is maintained and precipitation of particles is prevented by the action of the dispersion stabilizer. Polymerization is carried out at a polymerization temperature of 40 ° C. or higher, generally 50 to 90 ° C. In addition, the temperature may be raised in the latter half of the polymerization reaction, and further, in order to remove unreacted polymerizable monomers and by-products that cause odors during toner fixing, the latter half of the reaction or after the completion of the reaction. A part of the aqueous medium may be distilled off. After completion of the reaction, the produced toner particles are recovered by washing and filtration and dried. In the suspension polymerization method, it is usually preferable to use 300 to 3000 parts by weight of water as a dispersion medium with respect to 100 parts by weight of the monomer composition.

  As a polymerizable monomer for directly obtaining a toner by using a polymerization method, a styrene monomer such as styrene, o (m-, p-)-methylstyrene, m (p-)-ethylstyrene; ) Methyl acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, butyl (meth) acrylate, octyl (meth) acrylate, dodecyl (meth) acrylate, stearyl (meth) acrylate, (meth) (Meth) acrylate monomers such as behenyl acrylate, 2-ethylhexyl (meth) acrylate, dimethylaminoethyl (meth) acrylate, diethylaminoethyl (meth) acrylate; butadiene, isoprene, cyclohexene, (meta ) Diene monomers such as acrylonitrile and acrylamide are preferably used.

  Examples of polar resins used in the toner polymerization method include polymers of nitrogen-containing monomers such as dimethylaminoethyl methacrylate and diethylaminoethyl methacrylate, or a copolymer of nitrogen-containing monomers and styrene-unsaturated carboxylic acid esters. Nitrile monomers such as acrylonitrile; halogen-containing monomers such as vinyl chloride; unsaturated carboxylic acids such as acrylic acid and methacrylic acid; unsaturated dibasic acids; unsaturated dibasic acid anhydrides; A monomer polymer or a copolymer thereof and a styrene monomer; polyester; epoxy resin; More preferable examples include a copolymer of styrene and (meth) acrylic acid, a maleic acid copolymer, a saturated polyester resin, and an epoxy resin.

  Examples of the polymerization initiator include 2,2′-azobis- (2,4-dimethylvaleronitrile), 2,2′-azobisisobutyronitrile, and 1,1′-azobis (cyclohyxane-1-carbonitrile). ), 2,2′-azobis-4-methoxy-2,4-dimethylvaleronitrile, azo or diazo polymerization initiators such as azobisisobutyronitrile; benzoyl peroxide, methyl ethyl ketone peroxide, diisopropyl peroxycarbonate, cumene hydro Peroxide, t-butyl hydroperoxide, di-t-butyl peroxide, dicyl peroxide, 2,4-dichlorobenzoyl peroxide, lauroyl peroxide, 2,2-bis (4,4-t-butylperoxycyclohexyl) propane, tris- (T-Butylperu Sheet) such as triazine peroxide initiators; peroxide polymer initiator having a side chain; such persulfate potassium persulfate and ammonium persulfate; hydrogen peroxide, etc. are used. These can be used alone or in combination of two or more.

  The polymerization initiator is preferably added in an amount of 0.5 to 20 parts by mass with respect to 100 parts by mass of the polymerizable monomer.

  In order to control molecular weight, you may add a well-known crosslinking agent and a chain transfer agent, As a preferable addition amount, it is 0.001-15 mass parts with respect to 100 mass parts of polymerizable monomers.

  A suitable inorganic compound or organic compound stabilizer is used for the dispersion medium used in the production of the polymerization method toner by emulsion polymerization, dispersion polymerization, suspension polymerization, seed polymerization, or polymerization method using hetero-aggregation method. It is preferable to do. Examples of inorganic compound stabilizers include tricalcium phosphate, magnesium phosphate, aluminum phosphate, zinc phosphate, calcium carbonate, magnesium carbonate, calcium hydroxide, magnesium hydroxide, aluminum hydroxide, calcium metasilicate, Examples thereof include calcium sulfate, barium sulfate, bentonite, silica, and alumina. As stabilizers for organic compounds, polyvinyl alcohol, gelatin, methylcellulose, methylhydroxypropylcellulose, ethylcellulose, sodium salt of carboxymethylcellulose, polyacrylic acid and its salts, starch, polyacrylamide, polyethylene oxide, poly (hydroxystearic acid) -G-methyl methacrylate-eu-methacrylic acid) copolymers and nonionic or ionic surfactants.

  When the emulsion polymerization method and the heteroaggregation method are used, an anionic surfactant, a cationic surfactant, a zwitterionic surfactant and a nonionic surfactant are used. These stabilizers are preferably used in an amount of 0.2 to 30 parts by mass with respect to 100 parts by mass of the polymerizable monomer.

  Among these stabilizers, when an inorganic compound is used, a commercially available one may be used as it is, but in order to obtain fine particles, the inorganic compound may be produced in a dispersion medium.

  For fine dispersion of these stabilizers, 0001 to 0.1 parts by mass of a surfactant may be used with respect to 100 parts by mass of the polymerizable monomer. This surfactant is for promoting the stabilizing action of the dispersion stabilizer. Specific examples thereof include sodium dodecylbenzene sulfate, sodium tetradecyl sulfate, sodium pentadecyl sulfate, sodium octyl sulfate, sodium oleate, sodium laurate, potassium stearate, calcium oleate and the like.

  In the present invention, as the colorant used in the polymerization toner, it is necessary to pay attention to the polymerization inhibitory property and water phase transferability of the colorant. It is better to apply the process. In particular, dyes and carbon blacks have a polymerization inhibition property, so care must be taken when using them. A preferable method for surface-treating the dye system includes a method of polymerizing a polymerizable monomer in the presence of these dyes in advance, and the obtained colored polymer is added to the monomer system. Carbon black may be treated with a material that reacts with the surface functional groups of carbon black, such as polyorganosiloxane, in addition to the same treatment as the above dye.

  When the glass transition temperature of the binder resin is less than 40 ° C., the storability of the toner is lowered and the fluidity is deteriorated, and a good image tends not to be obtained. When the glass transition temperature of the binder resin exceeds 90 ° C., the low-temperature fixability is inferior, and the transparency of full color transparency is deteriorated. In particular, the halftone part is dull and a projected image with no saturation is likely to occur.

  The glass transition temperature (Tg) of the binder resin is measured by measurement according to ASTM D3418-8. For example, it is performed using DSC-7 manufactured by PerkinElmer. The temperature correction of the device detection unit uses the melting points of indium and zinc, and the correction of heat uses the heat of fusion of indium. For the sample, an aluminum pan is used, and an empty pan is set as a control.

  Next, the external additive that is externally added to the toner particles will be described.

  In the toner used in the present invention, inorganic fine particles such as silica, alumina and titanium oxide; fine powders of organic fine particles such as polytetrafluoroethylene, polyvinylidene fluoride, polymethyl methacrylate, polystyrene and silicone are externally added. Is preferred. By externally adding the above-mentioned fine powder to the toner particles, the fine powder exists between the toner and the carrier or between the toner particles, the developer fluidity is improved, and the developer life is also improved. To do. The average particle size of the fine powder is preferably 0.2 μm or less. When the number average particle diameter exceeds 0.2 μm, the effect of improving the fluidity is reduced, and the image quality may be deteriorated due to defects during development and transfer. The measurement of the number average particle diameter of these fine powders will be described later.

The surface area of these fine powders, the specific surface area by nitrogen adsorption ^{30 m} 2 / g or more measured by a BET method, is good especially in the range of 5~400m ² / g. The addition amount of the fine powder is preferably 0.1 to 20 parts by mass with respect to 100 parts by mass of the toner particles.

  Since the toner is a negatively chargeable toner, it is preferable from the viewpoint of chargeability to use at least one kind of hydrophobically treated silica. That is, since silica is more negatively charged than a fluidizing agent such as alumina or titanium oxide, the adhesion to toner particles is high, and the amount of free external additives is reduced. Therefore, filming on the electrostatic latent image carrier and contamination of the charging member can be suppressed. However, when the negative chargeability is increased, a part of the external additive that has been released tends to be transferred to the carrier. Even in that case, the polymerization method carrier of the present invention can suppress adhesion of the fluidizing agent because of its surface shape.

  In addition, the inorganic fine particles are preferably subjected to a hydrophobic treatment in order to maintain chargeability under high humidity. An example of the hydrophobic treatment is shown below.

  A silane coupling agent is mentioned as one of the hydrophobizing agents, and the amount thereof is 1 to 40 parts by mass, preferably 2 to 35 parts by mass with respect to 100 parts by mass of the inorganic fine particles. When the amount is 1 to 40 parts by mass, moisture resistance is improved and aggregates are hardly generated.

As a silane coupling agent used for this invention, what is shown by following General formula (3) is mentioned.
R _m SiY _n formula (3)
[In the formula, R represents an alkoxy group or a chlorine atom, m is an integer of 1 to 3, and Y represents a hydrocarbon group (for example, an alkyl group, a vinyl group, a glycidoxy group, or a methacryl group). , N is an integer of 3-1. ]
Specifically, for example, dimethyldichlorosilane, trimethylchlorosilane, allyldimethylchlorosilane, hexamethyldisilazane, allylphenyldichlorosilane, benzyldimethylchlorosilane, vinyltriethoxysilane, γ-methacryloxypropyltrimethoxysilane, Examples thereof include vinyltriacetoxysilane, divinylchlorosilane, dimethylvinylcholorsilane and the like.

  The silane coupling agent treatment of the inorganic fine particles is a dry treatment in which the vaporized silane coupling agent is reacted with the inorganic fine particles made into a cloud by stirring, or the inorganic fine particles are dispersed in a solvent and the silane coupling agent is dropped. The treatment can be performed by a generally known method such as a wet method for reacting. The above hydrophobization treatment can be used in combination as appropriate.

  Another example of the hydrophobizing agent is silicone oil.

As a preferable silicone oil, those having a viscosity at 25 ° C. of 5 to 2000 mm ² / s are preferably used. A silicone oil having a low molecular weight and a low viscosity is not preferable because volatile matter may be generated by heat treatment, while a silicone oil having a high molecular weight and a high viscosity is difficult to perform a surface treatment operation. As the silicone oil, methyl silicone oil, dimethyl silicone oil, phenylmethyl silicone oil, chlorophenyl methyl silicone oil, alkyl-modified silicone oil, fatty acid-modified silicone oil, and polyoxyalkyl-modified silicone oil are preferable.

  The above-described silicone oil is preferably a negatively chargeable oil having the same polarity as the toner particles in order to improve the chargeability of the toner.

  A known technique is used as a method of treating the inorganic fine particles with silicone oil. For example, inorganic fine particles and silicone oil may be directly mixed using a mixer such as a Henschel mixer, or a method of spraying silicone oil onto inorganic fine particles may be used. Alternatively, it may be prepared by dissolving or dispersing silicone oil in an appropriate solvent, mixing with inorganic fine particles, and then removing the solvent.

  The silicone oil is used in an amount of 1.5 to 60 parts by mass, preferably 3.5 to 40 parts by mass, with respect to 100 parts by mass of the inorganic fine particles to be treated. When the amount is 1.5 to 60 parts by mass, the surface treatment with silicone oil can be performed uniformly, and filming and voids can be suitably prevented, and the toner chargeability is prevented from deteriorating due to moisture absorption under high humidity, and durable. It is possible to prevent a decrease in image density.

  The additive for the purpose of imparting various toner characteristics preferably has an average particle diameter of 0.005 to 0.2 μm in the toner or from the viewpoint of durability when added to the toner. The average particle diameter of the additive means the number average particle diameter obtained by observing the surface of the toner particles with an electron microscope. As additives for the purpose of imparting these characteristics, for example, the following are used.

  In addition to the inorganic fine particles and organic fine particles described above, other fluidity imparting agents include metal oxides such as silicon oxide, aluminum oxide, and titanium oxide; carbon black; and carbon fluoride. Each of these is more preferably subjected to a hydrophobic treatment.

  Examples of the abrasive include metal oxides such as strontium titanate, cerium oxide, aluminum oxide, magnesium oxide and chromium oxide; nitrides such as silicon nitride; carbides such as silicon carbide; and calcium sulfate, barium sulfate and carbonate. Examples include metal salts such as calcium.

  Examples of the lubricant include fluorine resin powders such as vinylidene fluoride and polytetrafluoroethylene; and fatty acid metal salts such as zinc stearate and calcium stearate.

  Examples of the charge controllable particles or conductivity imparting particles include metal oxides such as tin oxide, titanium oxide, zinc oxide, silicon oxide and aluminum oxide; and carbon black.

  These additives are preferably used in an amount of 0.1 to 10 parts by weight, more preferably 0.1 to 5 parts by weight, based on 100 parts by weight of the toner particles. These additives may be used alone or in combination.

  The developer used in the present invention is used as a two-component developer by mixing the above-described magnetic carrier and toner.

  When a two-component developer is prepared by mixing toner and a magnetic carrier, good results are obtained when the mixing ratio is 3 to 30% by mass, preferably 4 to 20% by mass, as the toner concentration in the developer. can get. When the toner concentration is less than 3% by mass, the image density tends to be low, and when it exceeds 30% by mass, fogging or in-machine scattering tends to occur, and the useful life of the developer tends to decrease.

  The ratio (A / B) between the weight average particle diameter (A) of the toner and the 50% particle diameter (B) of the magnetic carrier is preferably 0.1 to 0.3. If it is less than 0.1, it becomes difficult to charge the toner satisfactorily, and the toner tends to be fogged or scattered in a high humidity environment. On the other hand, if it exceeds 0.3, the charge amount of the toner particularly under low humidity becomes too high, the stability of the self-control of the toner density is lowered, the fluctuation of the image density tends to be large, and the fog is likely to occur.

  Hereinafter, specific examples of measurement of the average particle size and particle size distribution of the toner will be shown.

  0.1 to 5 ml of a surfactant (alkylbenzene sulfonate) is attached to 100 to 150 ml of the electrolyte solution, and 2 to 20 mg of a measurement sample is added thereto. The electrolytic solution in which the sample is suspended is dispersed for 1 to 3 minutes with an ultrasonic disperser, and the aperture is adjusted to a toner size appropriately between 17 μm and 100 μm using the Coulter counter multisizer described above, and the volume is 0 based on the volume. Measure the particle size distribution of 3 to 40 μm. The number average particle diameter and weight average particle diameter measured under these conditions were determined by computer processing.

  By using the two-component developer of the present invention, the share of the developer in the developing device is small, and an image without image quality deterioration can be achieved even when a large number of copies are made.

In order to obtain a more tightened image, it is preferable to have a developing device for magenta, cyan, yellow, and black, and a tightened image can be obtained by performing black development last.
(Example)
EXAMPLES Hereinafter, although this invention is demonstrated concretely using an Example, this invention is not limited to these.
<1> Manufacture of magnetic carrier <Manufacture of magnetic carrier 1>
-Phenol (hydroxybenzene) 50 parts by weight-37 wt% formalin aqueous solution 80 parts by weight-Water 50 parts by weight-Magnetite fine particles surface-treated with an epoxy group-containing silane coupling agent 280 parts by weight (50% particle size 0.21 μm )
120 parts by mass of α-Fe ₂ O ₃ fine particles surface-treated with an epoxy group-containing silane coupling agent (50% particle size 0.35 μm)
-25 wt% ammonia water 15 parts by mass The above materials were put into a four-necked flask, heated to 85 ° C for 60 minutes while stirring and mixed, and reacted and cured for 120 minutes. After cooling to 28 ° C. and adding 500 parts by mass of water, the supernatant was removed, the precipitate was washed with water and air-dried. Next, this was dried under reduced pressure (665 Pa = 5 mmHg) at 180 ° C. for 24 hours to obtain a magnetic carrier core (A) having a phenol resin as a binder resin.

  A 5% by mass methanol solution of γ-aminopropyltrimethoxysilane was applied to the surface of the obtained magnetic carrier core (A).

  During coating, methanol was volatilized while coating while applying a shear stress to the magnetic carrier core (A) continuously.

  While stirring the magnetic carrier core (A) treated with the silane coupling agent in the processing machine at 70 ° C., the silicone resin SR2411 (manufactured by Toray Dow Corning Co., Ltd.) is 10% as the silicone resin solid content. After diluting with toluene, it was added under reduced pressure to coat 0.5% by mass of resin.

  Thereafter, the toluene was volatilized while stirring in a nitrogen gas atmosphere for 2 hours, and then heat treatment was performed at 140 ° C. for 2 hours in a nitrogen gas atmosphere to loosen the agglomeration, and then 200 mesh (75 μm aperture) The above coarse particles were removed to obtain a magnetic carrier 1.

The resin content of the obtained magnetic carrier 1 is 10% by mass, the 50% particle size is 35 μm, 21 μm or less is 0.1% by volume, 72 μm or more is 0.1% by volume, and the apparent density is 1.85 g / cm ^3. Met.

<Manufacture of magnetic carriers 2 and 3>
In the production example of the magnetic carrier 1, by changing the individual liquid ratio, the resin content is 10% by mass, the 50% particle size is 23 μm, 21 μm or less is 55.3% by volume, 72 μm or more is 0% by volume, apparent density Is 1.82 g / cm ³ of the magnetic carrier 2 and the resin content is 10% by mass, the 50% particle size is 58 μm, 21 μm or less is 0% by volume, 72 μm or more is 16% by volume, and the apparent density is 1.87 g / cm. ³ magnetic carrier 3 was obtained.

<Manufacture of magnetic carrier 4>
Ferrite component (Fe ₂ O ₃ : 56.3 mol%, MgO: 23.0 mol%, SrO: 20.7 mol%)
The ferrite raw material oxide blended in the above composition was wet mixed in a ball mill, dried and pulverized, then calcined at 750 ° C. for 2 hours, and pulverized to a crusher of about 0.1 to 1.0 mm. Furthermore, it is wet pulverized with a ball mill to form a slurry, and 1.0% of polyvinyl alcohol is added as a binder and 4% of CaCO3 is added as a pore adjusting agent. The mixture is granulated into spherical particles by a spray dryer method, and an oxygen gas concentration of 0.5%. Baked at 980 ° C. in a nitrogen gas atmosphere and sieved with a 200 μm sieve to remove coarse particles, then classified with an air classifier (Elbow Jet Lab EJ-L3, manufactured by Nippon Steel Mining Co., Ltd.). The particle size was adjusted to obtain core particles.

next,
Toluene and methyl ethyl ketone (4: 1) mixed solvent 1000 parts Styrene / methyl methacrylate copolymer (4: 6, Mw = 50,000) 70 parts Methyl methacrylate / perfluoropropylethyl methacrylate copolymer (80:20, Mw = 1) 80,000) 30 parts The above ingredients were mixed to prepare a coating liquid. Next, the composition of the solution was adjusted with respect to the core material particles so that the solid content of the coating resin was 10.0 wt%, and the solvent was removed by drying under reduced pressure while stirring and mixing with a vacuum kneader, at 140 ° C. for 2 hours. Baking and sieving with a sieve having an aperture of 74 μm, a 50% particle size is 35 μm, 21 μm or less is 3.8% by volume, 72 μm or more is 1.3% by volume, and an apparent density is 1.83 g / cm ³ . Carrier 4 was obtained.

<Manufacture of magnetic carriers 5 and 6>
In Production Example 4, 50% particle size was 35 μm and 21 μm in the same manner except that CaCO ₃ was changed to 2% and 7% as the pore adjuster and the coating resin solid content was 4.0 wt% and 350 wt%. The following is 2.7% by volume, 72 μm or more is 1.1% by volume, the magnetic carrier 5 has an apparent density of 2.4 g / cm ³ and 50% particle size is 35 μm, 21 μm or less is 5.8% by volume, and 72 μm or more A magnetic carrier 6 having 2.7% by volume and an apparent density of 1.1 g / cm ³ was obtained.

<Manufacture of magnetic carrier 7>
The 50% particle size is 35 μm and 21 μm or less in the same manner as in Production Example 4 except that the ferrite component (Fe ₂ O ₃ : 58 mol%, NiO: 21.0 mol%, ZnO: 21.0 mol%) is used. A magnetic carrier 7 having 2.5% by volume, 2.8% by volume of 72 μm or more, and an apparent density of 2.2 g / cm ³ was obtained.

<1> Manufacture of toner <Manufacture of toner 1>
To 710 parts by mass of ion-exchanged water, 450 parts by mass of 0.1 M Na ₃ PO ₄ aqueous solution was added and heated to 60 ° C., and then at 14000 rpm using a TK homomixer (made by Tokushu Kika Kogyo). Stir. To this, 68 parts by mass of 1.0 M CaCl ₂ aqueous solution was gradually added to obtain an aqueous medium having a pH of 5.8 containing a calcium phosphate compound.
Styrene 160 parts by mass n-butyl acrylate 34 parts by mass copper phthalocyanine pigment 10 parts by mass di-t-butylsalicylic acid aluminum compound 0.8 parts by mass saturated polyester 10 parts by mass ester wax (Mw: 500, Mn: 400, Mw / Mn: 1.25) 20 parts by mass The above materials were heated to 60 ° C., and uniformly dissolved and dispersed at 13000 rpm using a TK homomixer (manufactured by Tokushu Kika Kogyo Co., Ltd.). Into this, 10 g of a polymerization initiator 2,2′-azobis (2,4-dimethylvaleronitrile) was dissolved to prepare a polymerizable monomer composition. The polymerizable monomer composition was put into the aqueous medium, and stirred at 10,000 rpm for 10 minutes in a Claire mixer (manufactured by MTechnic Co., Ltd.) at 65 ° C. in an N2 atmosphere to prepare the polymerizable monomer composition. Grained. Thereafter, while stirring the aqueous medium with a paddle stirring blade, the temperature was raised to 80 ° C., and the polymerization reaction was carried out for 8 hours while maintaining the pH at 6.

  After the completion of the polymerization reaction, the mixture was cooled and hydrochloric acid was added to adjust the pH to 1.5 to dissolve calcium phosphate, followed by filtration, washing with water, drying, and classification to obtain polymer particles (toner particles 1).

The following two types of external additives are externally added to 100 parts by mass of the resulting polymer particles (toner particles 1), and after the external addition, coarse particles are removed with a 300 mesh (aperture 53 μm) sieve, and negatively charged. Cyan toner 1 was obtained. The weight average particle diameter of cyan toner 1 was 7.1 μm, and the average circularity was 0.977.
(1) First external additive (0.7 parts by mass of hydrophobic silica fine powder)
Hydrophobized with 100 parts by mass of silica fine powder with 10 parts by mass of hexamethyldisilazane in the gas phase, the BET specific surface area is 37 m ² / g, and the number average particle size is 30 nm.
(2) Second external additive (0.5 parts by mass of hydrophobic titanium oxide fine powder)
Hydrophobized with 10 parts by mass of n-hechiral trimethoxysilane in an aqueous medium to 100 parts by mass of fine titanium oxide powder, the BET specific surface area is 90 m ² / g, and the number average particle size is 35 nm. is there.

<Manufacture of toner 2>
・ Polyester resin consisting of terephthalic acid / fumaric acid / trimellitic anhydride / bisphenol A derivative 100 parts by mass ・ Copper phthalocyanine pigment 4 parts by mass ・ Aluminum compound of di-t-butylsalicylic acid 1 part by mass The mixture was preliminarily mixed, melt-kneaded with a twin-screw extrusion kneader, cooled and roughly pulverized to about 1 to 2 mm using a hammer mill, and then finely pulverized with an air jet type pulverizer. Further, the obtained finely pulverized product was classified and then subjected to spheronization treatment to obtain negative triboelectrically chargeable cyan toner particles 2 having a weight average particle size of 7.3 μm.

  In the same manner as in the production of cyan toner 1, two kinds of external additives were externally added to the obtained cyan toner particles to prepare negatively chargeable cyan toner 2. The cyan toner 2 had a weight average particle diameter of 7.3 μm and an average circularity of 0.951.

<Manufacture of toners 3 to 4>
After changing the classification conditions of the toner particles 2 to obtain toner particles 3 to 4, two external additives are externally added in the same manner as in the production of the toner 2, and the weight average particle diameter is 11.0 μm, the average circularity is 0. Cyan toner 3 having a weight of 949 and cyan toner 4 having a weight average particle diameter of 2.8 μm and an average circularity of 0.957 were obtained.

<Manufacture of toner 5>
Magenta polymer particles (toner particles) were obtained in the same manner as in the production of the toner 1 except that 10 parts by mass of a quinacridone pigment was used instead of the copper phthalocyanine pigment. In the same manner as in the production of the toner 1, two kinds of external additives were externally added to the obtained polymer particles to prepare a negatively chargeable magenta toner 5. The magenta toner 5 had a weight average particle diameter of 7.4 μm and an average circularity of 0.971.

<Manufacture of toner 6>
Instead of copper phthalocyanine pigment, C.I. I. Yellow polymer particles (toner particles) were obtained in the same manner as in the production of the toner 1 except that 5 parts by mass of Pigment Yellow 93 and 6 parts by mass of Solvent Yellow 93 were used. An external additive was externally added to the obtained polymer particles in the same manner as in the production of the toner 1 to prepare a negatively charged yellow toner 5. Yellow toner 5 had a weight average particle diameter of 7.3 μm and an average circularity of 0.968.

<Manufacture of toner 7>
Black polymer particles (toner particles) were obtained in the same manner as in the production of the toner 1 except that 10 parts by mass of carbon black was used in place of the copper phthalocyanine pigment. An external additive was externally added to the obtained polymer particles in the same manner as in the production of the toner 1 to prepare a negatively charged black toner 6. The black toner had a weight average particle diameter of 7.7 μm and an average circularity of 0.977.

  The carrier 1 (92 parts by mass) obtained above and cyan toner 1 (8 parts by mass) were mixed with a V-type mixer to obtain a starting cyan developer 1.

  Next, the developing device of a commercially available color copying machine CP2150 (manufactured by Canon) was modified as shown in FIG. 1, and 100 g of developer was added.

  Using an original document with an image area of 5% and using CLC 80g paper (manufactured by Canon Sales Co., Ltd.) in an environment of 23 ° C./60%, a 10,000 sheet passing test was performed while supplying cyan toner 1. Evaluation was performed based on the following evaluation method.

  The results are shown in Table 1. As can be seen from Table 1, good results were obtained.

[Evaluation methods and standards]
(1) Image density The image density was formed on plain paper with an original image density of 1.5 using a Macbeth Densitometer RD918 type (Macbeth Densitometer RD918manufactured by Mcbeth Co.) equipped with an SPI filter. It was measured as the relative density of the average of 5 points at the 4 corners and the center of the image.
(2) Halftone reproducibility Using the original image density of 0.3, the relative density was measured in the same manner as in (1).
A: 0.3 to 0.4
○: 0.25 to less than 0.3, more than 0.4 to 0.45
Δ: 0.20 to less than 0.25, more than 0.45 to 0.5
×: Less than 0.2, more than 0.5 (3) fog The average reflectance Dr (%) of plain paper before image printing was measured by a reflectometer (“REFLECTOMETER MODEL TC-6DS” manufactured by Tokyo Denshoku Co., Ltd.). It was measured. On the other hand, a solid white image was drawn on plain paper, and then the reflectance Ds (%) of the solid white image was measured. The fog (%) is calculated from the following formula.

Fog (%) = Dr (%) − Ds (%)
◎: Less than 0.4% ○: 0.4 to less than 0.8% Δ: 0.8 to less than 1.2% ×: 1.2% or more (4) Solid uniformity Using original image density of 1.5 (1) Similarly, the relative density of 5 points was measured and measured as the maximum density difference.
A: 0.0 to less than 0.05 B: 0.05 to less than 0.15 Δ: 0.15 to less than 0.25 x: 0.25 or more (Comparative Example 1)
A two-component developer was produced in the same manner as in Example 1 except that it was replaced with the carrier 2, and the image was printed and evaluated. Although it was initially good, the halftone uniformity and solid uniformity deteriorated due to durability. did. The evaluation results are shown in Table 1. This is presumably because the mixing property with the toner deteriorated due to the small particle size of the carrier.

(Comparative Example 2)
A two-component developer was produced in the same manner as in Example 1 except that the carrier 3 was used, and the image was printed and evaluated. As a result, the fog and solid uniformity deteriorated due to durability. The evaluation results are shown in Table 1. This is presumably because the charge imparting ability to the toner deteriorates due to the large particle size of the carrier, resulting in non-uniform charging.

  A two-component developer was produced in the same manner as in Example 1 except that it was replaced with the carrier 4, and imaged and evaluated. As a result, although fog and halftone uniformity slightly deteriorated due to durability, there was a practical problem. No results were obtained. The evaluation results are shown in Table 1. This is presumably because the carrier core material is ferrite, which increases the stress on the toner and makes the charge imparting ability of the carrier non-uniform.

(Comparative Example 3)
A two-component developer was produced in the same manner as in Example 1 except that the carrier 5 was used, and the image was printed and evaluated. As a result, the fog deteriorated and the halftone uniformity deteriorated due to durability. The evaluation results are shown in Table 1. This is presumably because the amount of resin in the carrier is small and the apparent density is large, so that the toner is easily damaged from the carrier, the toner spent is increased, and the toner is non-uniformly charged.

(Comparative Example 4)
A two-component developer was produced in the same manner as in Example 1 except that the carrier 6 was used, and the image was printed and evaluated. As a result, the fog deteriorated and the solid uniformity deteriorated due to durability. The evaluation results are shown in Table 1. This is presumably because the amount of the resin in the carrier is large and the resistance is high, so that charges are accumulated on the carrier and the toner cannot be uniformly charged.

  A two-component developer was produced in the same manner as in Example 1 except that the carrier 7 was used, and the image was printed and evaluated. As a result, although fog was slightly deteriorated, a result having no practical problem was obtained. The evaluation results are shown in Table 1. This is presumably because toner spent easily occurs because the heavy metal is contained, and the toner is not uniformly charged.

  In Example 1, the same procedure was performed except that the cyan toner 2 was used. As shown in Table 1, although the fogging was slightly deteriorated, a result having no practical problem was obtained. This is presumably due to the fact that the toner has a non-core / shell structure, so that the wax has migrated to the carrier surface.

  In Example 1, the same procedure was performed except that the cyan toner 3 was used. As shown in Table 1, although the halftone reproducibility and Dmax were slightly deteriorated, there were obtained practically no problems. This is presumably because the development uniformity was slightly deteriorated because the toner particle size was increased.

  Example 1 was carried out in the same manner except that cyan toner 4 was used. As shown in Table 1, although the fogging and Dmax were slightly deteriorated, practically satisfactory results were obtained. This is presumed to be due to the fact that the toner particle size became smaller and the charge became slightly non-uniform.

  Except that yellow toner 6, magenta toner 5, cyan toner 1 and black toner 7 were used, image output was performed and evaluated in the same manner as in Example 1. As a result, as in Example 1, good results were obtained.

1 is a diagram showing an embodiment of an image forming apparatus of the present invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Photosensitive drum 2 Developing apparatus 3 Developer 3a Magnetic carrier 3b Toner 4 Developing sleeve 5 Magnet roller 6 1st doctor blade 7 2nd doctor blade 8 Toner hopper 11 Developer accommodating member 20 Toner supply opening A A Developer accommodating part A

Claims (11)

While rotating the developing sleeve having the magnetic field generating means inside, the developer containing the toner and the magnetic carrier in the developer accommodating portion is removed by the developer regulating member on the downstream side in the developer conveying direction of the developer accommodating portion. The developer is transported by regulating the transport amount toward the developing area, and the developer containing part that contains the developer blocked by the developer regulating member, and adjacent to the developer containing part from the upstream side in the developer transport direction And a toner container having a toner replenishment opening facing the surface of the developing sleeve at a position where the developer is moved to a capacity of the developer in the developer container by conveying the developer on the developing sleeve. In a two-component developer used for a developing device that takes in the toner in the toner storage portion into the developer storage portion accordingly,
The magnetic carrier is a resin-coated carrier having at least a magnetic core material and a resin,
The resin content is 5 to 25% by mass, the apparent density is 1.2 to 2.3 g / cm ³ , the average particle size is 25 to 55 μm, and 21 μm or less is 0.01 to 12% by volume. A two-component developer in which 72 μm or more is 1.0% by volume or less.   The magnetic core material is magnetite or ferrite containing at least one magnetic oxide of an element selected from a light metal group consisting of Fe, Li, Be, Mg, Ca, Sr, and Rb, or at least inorganic compound particles and a binder resin. The two-component developer according to claim 1, wherein the two-component developer is a magnetic fine particle-dispersed resin carrier.   The two-component developer according to claim 2, wherein the binder resin of the magnetic fine particle dispersed resin carrier is a magnetic fine particle dispersed resin carrier having a thermosetting phenol resin.   4. The two-component developer according to claim 1, wherein the toner has a weight average particle diameter of 3.0 to 10.0 μm and contains 1 to 40% by mass of a solid wax.   The two-component developer according to claim 4, wherein the toner is a polymerized toner.   6. The two-component developer according to claim 5, wherein the toner has a core / shell structure, and the core is formed of a release agent and / or a low softening point substance. While rotating the developing sleeve having the magnetic field generating means inside, the developer containing the toner and the magnetic carrier in the developer accommodating portion is removed by the developer regulating member on the downstream side in the developer conveying direction of the developer accommodating portion. The developer is transported by regulating the transport amount toward the developing area, and the developer containing part that contains the developer blocked by the developer regulating member, and adjacent to the developer containing part from the upstream side in the developer transport direction And a toner container having a toner replenishment opening facing the surface of the developing sleeve at a position where the developer is moved to a capacity of the developer in the developer container by conveying the developer on the developing sleeve. A developing device that takes the toner in the toner storage portion into the developer storage portion accordingly,
The magnetic carrier constituting the developer is a resin-coated carrier having at least a magnetic core material and a resin,
The resin content is 5 to 25% by mass, the apparent density is 1.2 to 2.3 g / cm ³ , the average particle size is 25 to 55 μm, and 21 μm or less is 0.01 to 12% by volume. , 15 μm or less is 3.0% by volume or less, 50 μm or more is 0.1 to 20% by volume, and 72 μm or more is 1.0% by volume or less.   The developing device according to claim 7, further comprising a peeling member that faces the surface of the developing sleeve in a non-contact manner in the developer accommodating portion and peels an upper layer portion of the developer carried and conveyed by the developing sleeve. Positioned between the toner replenishment opening facing the surface of the developing sleeve of the toner accommodating portion and the developer accommodating portion, and is carried and conveyed from the facing portion of the toner accommodating portion toward the developer accommodating portion. A second developer regulating member that regulates the amount of the developer on the developing sleeve;
8. The gap between the second developer regulating member and the developing sleeve surface is set so that the regulated amount of the developer increases with an increase in toner concentration of the developer on the developing sleeve. The developing device according to any one of Items 8 to 8.   The developing device according to claim 7, wherein the peeling member is made of a magnetic material. The developing device according to claim 10, wherein the peeling member is a roller-like rotating member, and a plurality of the magnetic poles are magnetized on the surface of the peeling member.

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