JP4687592B2 - Toner for electrostatic image development - Google Patents

Description

  The present invention relates to an electrostatic charge image developing toner used for electrophotographic image formation.

  In the field of electrophotographic image forming technology, with the progress of digitalization in recent years, a small-diameter toner capable of forming a high-definition image is required. Under such a background, a method for producing a toner by a polymerization method capable of obtaining a small-diameter toner without undergoing a conventional kneading and pulverizing process has attracted attention (for example, see Patent Document 1).

  The toner produced by the polymerization method is easy to obtain a small diameter toner having a sharp shape distribution and a uniform charge amount, compared with the toner obtained by the kneading and pulverization method, so that high-definition image quality reproduction is required. Advantageous characteristics for digital image formation. In addition, since a kneading / pulverizing step is not required, energy consumption and cost at the time of toner production can be reduced, so that it is possible to provide a toner with high production efficiency and environmentally friendly.

  By the way, the toner produced by the polymerization method tends to exhibit higher water content than the toner obtained by the kneading / pulverization method because there are many steps in which moisture is interposed, as represented by the particle formation step in the aqueous medium. There is. Thus, studies have been conducted to stably form a good toner image even in a case where image formation is performed in an environment where the toner may affect the charging property due to moisture absorption, such as a high temperature and high humidity environment. Has also been done.

  Among them, there is a technique for improving image forming performance in a high temperature and high humidity environment by paying attention to the presence of a specific element in the toner. For example, with respect to a polymerized toner produced by a suspension polymerization method, a technique (for example, refer to Patent Document 2) for setting the content of metal ions attributed to a poorly water-soluble compound to a specific range, or a positive toner contained in the toner. By specifying the total amount of ions, a technique for improving the chargeability of the toner in a high-temperature and high-humidity environment can be cited (see, for example, Patent Document 3).

Furthermore, paying attention to the ratio of the total content of elements such as magnesium, calcium, barium, zinc, aluminum, and phosphorus and the content of sulfur elements, a toner-related technology that provides stable charging characteristics regardless of the environment. (For example, refer to Patent Document 4).
JP 2000-214629 A JP-A-8-160661 JP 2000-330330 A JP 2005-62807 A

  However, the technique disclosed in the above-mentioned patent document exhibits the disclosed performance in a case where image formation is performed in a high temperature and high humidity environment of a certain level, but in an environment where the temperature and humidity fluctuate frequently. Thus, it has been difficult to form a stable image. As described above, in a case where the image forming environment frequently changes, a toner capable of forming a stable image has not yet been realized.

  The present invention provides an electrostatic charge image developing toner (hereinafter also simply referred to as toner) capable of stably producing a printed image having good image quality without being influenced by the influence of environmental fluctuations. It is intended. In other words, a toner image with stable image density can be obtained without causing a change in chargeability with respect to environmental fluctuations, and a toner capable of obtaining a high density toner image even when continuous printing over a large number of sheets is performed. The purpose is to provide.

  The object of the present invention is achieved by adopting the following configuration.

1.
An electrostatic charge image developing toner containing at least a binder resin, a colorant, a phosphorus (P) element, and a potassium (K) element,
The binder resin is a resin containing a carboxyl group,
50 ppm or more and 3000 ppm or less of phosphorus (P) element,
A toner for developing an electrostatic charge image, comprising 300 ppm or more and 4000 ppm or less of a potassium (K) element.

2.
An electrostatic charge image developing toner containing at least a binder resin, a colorant, a phosphorus (P) element, and a sodium (Na) element,
The binder resin is a resin containing a carboxyl group,
50 ppm or more and 3000 ppm or less of phosphorus (P) element,
A toner for developing an electrostatic charge image, comprising a sodium (Na) element in a range of 150 ppm to 2300 ppm.

3.
An electrostatic charge image developing toner containing at least a binder resin, a colorant, a phosphorus (P) element, a potassium (K) element, and a sodium (Na) element,
The binder resin is a resin containing a carboxyl group,
50 ppm or more and 3000 ppm or less of phosphorus (P) element,
A potassium (K) element of 300 ppm to 4000 ppm,
A toner for developing an electrostatic charge image, comprising a sodium (Na) element in a range of 150 ppm to 2300 ppm.

  The toner according to the present invention always develops a certain level of charged state regardless of the influence of the environment. Therefore, even if image formation is performed in an environment where there is a concern that the image density may fluctuate in the prior art. Thus, it has become possible to stably produce print images with good image quality. That is, according to the present invention, the toner chargeability fluctuations are suppressed, and a toner image with a stable image density can be obtained even when the environment fluctuates. A high-density toner image can be formed stably. As described above, according to the present invention, a toner image having a predetermined image density can be stably formed without being substantially affected by environmental fluctuations.

  In particular, in a toner containing 50 ppm to 3000 ppm of phosphorus (P) element, 300 ppm to 4000 ppm of potassium (K) element, and 150 ppm to 2300 ppm of sodium (Na) element, the above effect is most remarkably exhibited. Even in an environment where the humidity in the air is likely to fluctuate, stable image formation can be reliably performed without causing fluctuations in the charge amount.

  The present invention relates to a toner containing a specific amount of a phosphorus element and a potassium element, or a phosphorus element and a sodium element, and further a phosphorus element, a potassium element, and a sodium element.

  The present inventor has examined the factors that change the chargeability of the toner, and presumed that the factor exists in the molecular structure of the binder resin constituting the toner. In other words, paying attention to the presence of a polar group such as a carboxyl group contained in the molecule constituting the binder resin, it is assumed that if the dissociation state of the polar group is maintained at a certain level, the chargeability of the toner is less likely to fluctuate. is there. Then, by controlling the amount of various elements including metal elements, it was considered that the dissociation state of the polar group was maintained at a constant level in the toner particles.

  This is because when a phosphorus element and a potassium element or a phosphorus element and a sodium element coexist in a toner particle under specific conditions, a buffering action is expressed by these elements, and the charging action of the toner is caused by this buffering action. Is assumed to be maintained at a certain level. In other words, the pH of the toner particles is kept weakly alkaline by the buffering action, and the dissociation state of the carboxyl groups present in the molecules is constant in the binder resin constituting the toner particles, and the amount of charging sites is kept constant. It is guessed. Further, in this state, it is presumed that the affinity with water molecules is also constant, and it is considered that the effect is such that the change in chargeability is further suppressed.

  Furthermore, when three elements of phosphorus element, potassium element, and sodium element are contained under a specific range of contents, a buffering action is expressed between the three elements, and more than when two elements coexist. It is presumed that the pH can be kept at a weak alkali. In this way, the affinity for water molecules is maintained at a constant level due to the interposition of the three elements, and the chargeability is less likely to fluctuate even in a high temperature and high humidity environment (for example, 30 ° C., 80% RH). It is presumed that

  As described above, since the toner according to the present invention can suppress fluctuations in chargeability, even if image formation is performed in an environment where there is a concern that fluctuations in image density may occur in the prior art, image density and A print image having a stable image quality with no variation in image uniformity is formed.

  Hereinafter, the present invention will be described in detail.

  The toner capable of exhibiting the effect of the present invention includes toner particles containing 50 ppm to 3000 ppm of phosphorus (P) element and 300 ppm to 4000 ppm of potassium (K) element. ) Containing 50 ppm or more and 3000 ppm or less of the element, 150 ppm or more and 2300 ppm or less of the sodium (Na) element, and further containing 50 ppm or more and 3000 ppm or less of phosphorus (P) element, And it contains 150 ppm or more and 2300 ppm or less of sodium (Na) element.

  In the present invention, it has been found that the charge site amount of the toner can be controlled by specifying the contents of phosphorus element and potassium element, and phosphorus element and sodium element. This is because, when the contents of the two sets of elements are within a specific range, an electrically appropriate interaction (buffer action) occurs between the two elements, and the pH in the toner particles becomes a constant level. As a result, the dissociation state of the carboxyl groups in the binder resin constituting the toner particles is maintained at a constant level, and even if the image forming environment changes, the dissociation state of the carboxyl groups is not affected, and the amount of charged sites is constant. It is estimated that In addition, by specifying the content of potassium element or sodium element and the content of phosphorus element, the influence of what promotes moisture adsorption on the toner surface such as potassium element or sodium element is suppressed, for example, the humidity increases. However, it is estimated that the charge level is maintained.

  As described above, the present invention maintains the chargeability of the toner at a certain level by controlling the dissociation state of the carboxyl group in the binder resin by utilizing the buffer action generated between the two specific elements in the toner particles. However, stable image formation can be performed even if the image forming environment fluctuates.

  In the toner according to the present invention, as described above, in the toner containing phosphorus element and potassium element, the content of phosphorus element is 50 ppm or more and 3000 ppm or less, preferably 500 or more and 3000 ppm or less. Further, the content of potassium element is 300 ppm to 4000 ppm, preferably 1100 to 2800 ppm.

  In the toner containing phosphorus element and sodium element, the content of phosphorus element is 50 ppm or more and 3000 ppm or less, preferably 500 ppm or more and 3000 ppm or less. Further, the content of sodium element is 150 ppm or more and 2300 ppm or less, preferably 300 or more and 1700 ppm or less.

  Further, in the toner containing phosphorus element, potassium element and sodium element, the phosphorus element is 50 ppm or more and 3000 ppm or less, preferably 500 ppm or more and 3000 ppm or less. Further, the content of potassium element is 300 ppm to 4000 ppm, preferably 1100 ppm to 2800 ppm. The content of sodium element is 150 ppm or more and 2300 ppm or less, preferably 300 ppm or more and 1700 ppm or less.

  The contents of the phosphorus element, potassium element, and sodium element contained in the toner according to the present invention are in the above-described range. On the other hand, when the contents of phosphorus element, potassium element and sodium element in the toner according to the prior art are measured by the same method, phosphorus element is not contained, potassium element is contained in 80 ppm to 400 ppm, and sodium element is contained in 400 ppm to 1000 ppm. It was a thing. As described above, the toner according to the prior art does not contain phosphorus element, and the content of potassium element or sodium element is small, though there is an overlapping range as compared with the toner according to the present invention. Further, as in Patent Document 4 described above, it is considered that there was a technical idea focusing on the content of phosphorus element in the toner, but in Patent Document 4, the contents of phosphorus element and metal element are specified respectively. To do was not described.

  Thus, the present invention can be easily conceived from the prior art that a stable toner that is not affected by environmental fluctuations can be obtained by specifying the contents of phosphorus element, potassium element, and sodium element. We have found a technology that can be said to be difficult.

  The addition method of the phosphorus element, potassium element, and sodium element contained in the toner according to the present invention into the toner particles is not particularly limited. For example, the addition is performed in the aggregation process in which the particles grow during the manufacturing process. Is mentioned. In particular, it is preferable to add it when the particle growth is almost completed, and it is also possible to add it when starting the particle growth or in the shape control step described later. Furthermore, it is also possible to add after particle formation. In addition, the contents of phosphorus element, potassium element, and sodium element can be adjusted by adjusting the addition amount of the compound containing these elements, or by adjusting the washing conditions in the solid-liquid separation / washing process described later. It is possible to control. Examples of the method for adjusting the cleaning conditions include the number of times of cleaning.

  Hereinafter, specific examples relating to a method for adding a phosphorus element, a potassium element, and a sodium element will be described through the description of the manufacturing process of the toner according to the present invention.

  The method for producing the toner according to the present invention is not particularly limited, but as one example, there is a production method for producing a toner through a step of forming resin particles by emulsion polymerization and aggregating the resin particles. It is done.

  Hereinafter, a toner manufacturing method according to this method will be described.

The manufacturing method performed through the steps of forming resin particles capable of producing the toner according to the present invention and aggregating the resin particles is performed through the following steps.
(1) Polymerization step of polymerizing a polymerizable monomer to prepare a resin particle dispersion (2) The resin particles produced in the polymerization step are added to an aqueous medium together with colorant particles to aggregate the resin particles (3) Following the agglomeration step, operations such as heating and agitation are carried out to proceed with the fusion of the materials constituting the agglomerates (also referred to as toner particle intermediates) to control the shape of the agglomerates. Shape control step (4) Solid-liquid separation of the produced toner particle intermediate from the aqueous medium and solid-liquid separation and washing step for cleaning the surface of the toner particle intermediate (5) Solid-liquid separation and washing step (6) An external additive processing step for making the toner usable for image formation by adding an external additive to the dried toner particle intermediate. Is.

  Hereinafter, each step will be specifically described.

[Polymerization process]
In a preferred example of the polymerization step, a radically polymerizable monomer solution is added to an aqueous medium containing a surfactant, mechanical energy is applied to form droplets, and then water-soluble radical polymerization is initiated. The polymerization reaction proceeds in the droplets by radicals from the agent. In addition, you may add the resin particle as a core particle in the said aqueous medium.

  In the polymerization, it is preferable to control the molecular weight distribution in several stages by changing the amount of the chain transfer agent. By this polymerization step, resin particles are obtained.

  Such resin particles may contain a release agent (wax) or may contain a colorant. The colored resin particles can be obtained by polymerizing a monomer composition containing a colorant.

  Further, when using uncolored resin particles, in the aggregation step described later, the toner particles are aggregated by adding the colorant particle dispersion to the resin particle dispersion and aggregating the resin particles and the colorant particles. It can be an intermediate (toner base).

[Aggregation process]
This step is a step of growing the particles by aggregating the resin particles in the aqueous medium.

  In this step, the resin particles produced in the polymerization step are aggregated with toner particle constituent materials such as colorant particles, whereby a toner particle intermediate (before a function as a toner is imparted by a final treatment such as an external additive treatment). Particles, also referred to as toner matrix and colored particles). In this step, agglomeration (fusion) is also performed in which the aggregated particles are firmly bonded together by an action such as heat.

In the present invention, the concentration (content) of phosphorus element, potassium element, and sodium element in the toner is determined depending on the amount of the compound containing phosphorus element, potassium element, and sodium element added to the aqueous medium. Can be adjusted.
Is possible.

  Specifically, by adding a divalent or trivalent salt in the aqueous medium, the electrostatic repulsion between the particles such as the resin particles and the colorant particles is alleviated. These particles aggregate and grow to form a toner particle intermediate. The agglomerated particles are fused by being bonded by receiving an action such as heat. In this way, the toner particle intermediate is formed and grown.

  The step of aggregating the resin particles will be further described. In the step of aggregating the resin particles, as described above, the resin particles and colorant particles generated in the polymerization step are agglomerated and the particles are fused in a temperature environment equal to or higher than the glass transition temperature of the resin particles. is there.

  Particle agglomeration is performed by mixing a resin particle dispersion or a colorant particle dispersion below the glass transition temperature of the resin particles, and simultaneously fusing the agglomerated particles by fusing the particles while aggregating the particles. There is a method of aggregating particles. According to this method, since the fusion can proceed while growing the particles, there is an advantage that the particle shape and the particle size distribution can be easily controlled.

  From this point of view, in the step of aggregating the resin particles, agglomeration and fusion (fusion) are advanced in parallel to grow to the desired particle size and heating is continued to control the particle shape as necessary. It is preferable to use a so-called “salting out / fusion method”.

  The “aqueous medium” in the present invention refers to a material whose main component (50% by mass or more) is water. Examples of components other than water include water-soluble organic solvents such as methanol, ethanol, isopropanol, butanol, and acetone.

  Aggregation of particles is promoted by adding a metal salt such as a divalent salt. Examples of the metal salt that promotes aggregation include monovalent alkali metal salts such as sodium, potassium, and lithium, divalent metal salts such as calcium, magnesium, manganese, and copper, and trivalent metal salts such as aluminum and iron. Etc. Specific examples include sodium chloride, potassium chloride, lithium chloride, calcium chloride, magnesium chloride, zinc chloride, copper sulfate, magnesium sulfate, and manganese sulfate. These salts may be used alone or in combination of two or more.

  Among these metal salts, a divalent metal salt is particularly preferable because aggregation can be advanced with a small addition amount.

  The addition amount of these metal salts is preferably added so that the concentration of the metal salt is equal to or higher than the critical aggregation concentration in the aqueous medium, specifically, 1.2 times the critical aggregation concentration or more, preferably It is preferable to add 1.5 times or more. Here, the “critical aggregation concentration” is an index relating to the stability of the aqueous dispersion. The critical aggregation concentration can be calculated in detail, for example, by the technique described in Seizo Okamura et al., “Polymer Chemistry, Vol 17, 601 (1960) (edited by the Society of Polymer Science)”. Also, a desired salt is added to the target dispersion for aggregation at different concentrations, the ζ (zeta) potential of the dispersion for aggregation is measured, and the salt concentration at which this value changes is calculated as the critical aggregation concentration. It is also possible.

  In the step of aggregating the resin particles, it is possible to agglomerate toner particle constituent materials such as wax, fixing aid, charge control agent and the like together with the resin particles and the colorant particles.

  In addition, when a compound containing phosphorus element, potassium element, or sodium element is added to the aqueous medium in the aggregation step, it is possible to use the following oxo acids, potassium salts, sodium salts, and the like thereof. This will be described below.

As a method of adding a compound containing phosphorus element, potassium element, and sodium element to the aqueous medium in the aggregation step, for example,
(1) Method of adding potassium salt or sodium salt of oxo acid containing phosphorus element (2) Method of adding oxo acid containing phosphorus element and potassium salt or sodium salt containing phosphorus element ( 3) A method of adding an oxo acid containing a phosphorus element and a potassium salt or sodium salt of an oxo acid not containing a phosphorus element can be mentioned.

  These oxo acids are represented by the following general formula (1).

Formula (1); XO _m (OH) _n
That is, X in the formula corresponds to an oxo acid containing phosphorus element, and OH of OH replaced with potassium element or sodium element corresponds to potassium salt or sodium salt To do. In addition, m and n in a formula represent an integer.

Examples of the oxo acid containing phosphorus element and the potassium salt and sodium salt thereof include the following compounds. That is,
Compound 1; phosphoric acid (H ₃ PO ₄ ) and its potassium salt, sodium salt Compound 2; orthophosphoric acid (H ₄ P ₂ O ₆ or (OH) ₂ PO—PO (OH) ₂ ) and its potassium Salt, sodium salt compound 3; phosphorous acid (H ₃ PO ₃ or (HO) ₃ P) and its potassium salt, sodium salt compound 4; pyrophosphoric acid (also referred to as diphosphoric acid) (H ₄ P ₂ O ₇ Or (OH) ₂ PO—O—PO (OH) ₂ ) and its potassium salt, sodium salt Compound 5; hypophosphoric acid (also referred to as diphosphorus (IV) acid) (H ₄ P ₂ O ₆ or (OH ) ₂ PO—PO (OH) ₂ ) and its potassium salt, sodium salt Compound 6: Isohypophosphoric acid ((OH) (H) PO—PO (OH) ₂ ) and its potassium salt, sodium salt Compound 7; diphosphorus (III, V) acid ((OH) ₂ P— _{O-PO (OH) 2)} , and its potassium salt, sodium salt compound 8; triphosphate (H ₅ P ₃ O ₁₀ or _{(OH) 2 PO-O-} PO (OH) -PO (OH) 2) And its potassium salt, sodium salt Compound 9; metaphosphoric acid ((HPO ₃ ) _n or (— (OH) PO—O—) _n ), and its potassium salt, sodium salt Among the potassium salts and sodium salts of oxo acids containing phosphorus element, particularly preferred compounds are potassium pyrophosphate, sodium pyrophosphate, dipotassium dihydrogen pyrophosphate, disodium dihydrogen pyrophosphate, potassium phosphate, Examples thereof include sodium phosphate.

In addition to the method of adding the potassium salt and sodium salt, in addition to the oxo acid containing the phosphorus element, a method of using the potassium salt and sodium salt of the oxo acid containing the silicon element and boron element shown below together Can be mentioned. That is,
Compound 10: potassium salt or sodium salt of orthosilicic acid (H ₄ SiO ₄ or (OH) ₄ Si) Compound 11; metasilicic acid ((H ₂ SiO ₃ ) _n or (— (OH) ₂ Si—O—) _n ) Potassium salt, sodium salt Compound 12; orthoboric acid (also referred to as boric acid) (H ₃ BO ₃ or (HO) ₃ B) potassium salt, sodium salt Compound 13; metaboric acid ((HBO ₂ ) _n or (-( HO) B—O—) _n ) potassium salt, sodium salt Compound 14; perboric acid (H ₂ B ₂ (O ₂ ) ₂ (OH) ₄ ) potassium salt, sodium salt Compound 15; hypoboric acid (H ₄ B ₂ O ₄ or (HO) ₂ BB (OH) ₂ ) potassium salt, sodium salt Compound 16; pentaboric acid (HB ₅ O ₈ ) potassium salt, sodium salt In the present invention, the phosphorus element is 50 ppm. More than 3000p m or less and, 300 ppm or more 4000ppm or less elemental potassium, or by toner containing a sodium element 150ppm or 2300ppm or less, the above effect is expressed. When adding a compound containing phosphorus element, potassium element, and sodium element in the aggregation step, if the compound is added in an amount of 0.5 to 7.0 parts by mass with respect to 100 parts by mass of the aqueous medium, the content of each element is as follows. A toner within the above range is produced.

  The contents of the phosphorus element, potassium element, and sodium element contained in the toner particles according to the present invention can be quantified by, for example, a fluorescent X-ray analyzer (WDX).

  An X-ray fluorescence analyzer (WDX) irradiates a sample with continuous X-rays to generate characteristic X-rays (fluorescence X-rays) unique to the elements constituting the sample. Then, the generated fluorescent X-rays are spectrally dispersed (wavelength dispersion type) with a spectroscopic crystal to generate a spectrum, and the obtained spectrum is measured to quantitatively analyze elements constituting the sample.

The above-described element quantification method using a fluorescent X-ray analyzer is performed in the following procedure.
(1) First, a sample for preparing a calibration curve is prepared. A known amount of potassium phosphate or sodium phosphate is added to 100 parts by mass of styrene powder, mixed with a 2 L Henschel mixer, and then a measurement pellet is prepared.
(2) The prepared pellet is measured with a fluorescent X-ray analyzer, and a calibration curve is created from the mixing ratio of potassium phosphate or sodium phosphate in styrene powder and the peak intensity obtained from each sample.
(3) Next, the toner is measured with a fluorescent X-ray analyzer, and the peak intensity obtained is collated with a calibration curve to calculate the contents of phosphorus element, potassium element, and sodium element.

  As a specific fluorescent X-ray analyzer, for example, an X-ray fluorescent analyzer “XRF-1800” (manufactured by Shimadzu Corporation) is used, and in this apparatus, Kα ray of rhodium (Rh) is used, and 20 kV, It can be performed under an output condition of 100 mA.

  Further, the contents of potassium element and sodium element can be quantified using an inductively coupled plasma spectrometer (ICP).

[Shape control process]
This is a step of controlling the shape of the toner particle intermediate (toner base material) by continuing the heating and stirring following the above-described aggregation step. When the heating and stirring time is lengthened, the shape of the toner particle intermediate (toner base) becomes nearly spherical, and the shape of the toner particle intermediate becomes non-spherical as the heating and stirring time becomes shorter.

[Solid-liquid separation and washing process]
In the solid-liquid separation / washing step, a solid-liquid separation process in which the toner particle intermediate (toner base) is solid-liquid separated from the dispersion of the toner-particle intermediate (toner base) cooled to a predetermined temperature in the above step; And a cleaning process for removing unnecessary substances such as surfactants from the solid-liquid separated toner cake (a lump obtained by agglomerating a toner particle intermediate (toner base) in a wet state) into a cake. The

  In the washing treatment, the filtrate is washed with water until the electric conductivity of the filtrate reaches 10 μS / cm.

  Here, the solid-liquid separation and washing methods are not particularly limited, such as a centrifugal separation method, a vacuum filtration method using Nutsche or the like, a method using a filter press or the like.

[Drying process]
The drying step is a step of drying the cleaned toner particle intermediate. In the drying process, the drying process is usually performed in the state of a toner cake. Examples of dryers used in this process include spray dryers, vacuum freeze dryers, vacuum dryers, etc., stationary shelf dryers, mobile shelf dryers, fluidized bed dryers, rotary dryers It is preferable to use a stirring dryer or the like. The water content of the dried toner particle intermediate is preferably 5% by mass or less, and more preferably 2% by mass or less. In the case where toner particle intermediates (toner base materials) that have been dried are agglomerated weakly due to the attractive force between the particles, the agglomerates may be crushed. Here, as the crushing treatment apparatus, a mechanical crushing apparatus such as a jet mill, a Henschel mixer, a coffee mill, or a food processor can be used.

[External process]
In this step, an external additive is mixed with the dried toner particle intermediate (toner base) to produce a toner that can be used for image formation.

  As an external additive mixing device, a mechanical mixing device such as a Henschel mixer or a coffee mill can be used.

  Next, the physical properties of the toner according to the present invention will be described.

(Median diameter based on volume (D ₅₀ ))
The toner according to the present invention preferably has a volume-based median diameter (D ₅₀ ) of 3 to 8 μm.

For the median diameter (D ₅₀ ) of the toner based on the volume and the coefficient of variation in the particle size distribution based on the volume, a computer system for data processing (manufactured by Beckman Coulter) is added to “Multisizer 3” (Beckman Coulter). Measurement and calculation can be performed by using a connected device.

  As a measurement procedure, 0.02 g of toner is used in 20 ml of a surfactant solution (for example, a surfactant solution obtained by diluting a neutral detergent containing a surfactant component 10 times with pure water for the purpose of dispersing the toner). Then, ultrasonic dispersion is performed for 1 minute to prepare a toner dispersion. This toner dispersion is poured into a beaker containing ISOTON II (manufactured by Beckman Coulter, Inc.) in a sample stand with a pipette until a measurement concentration of 8% by mass, and the measuring machine count is set to 2500 and measured. . The aperture diameter of “Multisizer 3” is 50 μm.

(Coefficient of variation in volume-based particle size distribution)
The coefficient of variation in the volume-based particle size distribution of the toner according to the present invention is preferably 12 to 22%, more preferably 10 to 22%.

  The coefficient of variation in the volume-based particle size distribution is calculated from the following equation.

Coefficient of variation (%) in volume-based particle size distribution = (S ₂ / Dn) × 100
(In the formula, S ₂ represents the standard deviation in the volume-based particle size distribution, and Dn represents the median diameter (D ₅₀ ) based on the volume).
(Average circularity)
The average circularity of the toner according to the present invention is preferably 0.951 to 0.990.

  The circularity of the toner is defined by the following formula.

Circularity = (perimeter of a circle having the same projection area as the particle image) / (perimeter of the particle projection image)
The average circularity is a value calculated by dividing the sum of the circularity of each particle by the total number of particles.

  The circularity of the toner is a value measured using “FPIA-2100” (manufactured by Sysmex). Specifically, the toner is blended with an aqueous solution containing a surfactant, subjected to ultrasonic dispersion treatment for 1 minute to disperse the toner, and then measured using “FPIA-2100”. Measurement conditions are set to the HPF (high magnification imaging) mode and the number of HPF detections is set to an appropriate density of 3000 to 10,000.

(Molecular weight of resin)
The molecular weight of the resin constituting the toner according to the present invention is preferably 1000 to 100,000 in terms of number average molecular weight (Mn) and 2,000 to 1,000,000 in terms of weight average molecular weight (Mw). The molecular weight of the resin constituting the toner can be calculated by, for example, gel permeation chromatography or gel permeation chromatography.

  Here, molecular weight measurement by gel permeation chromatography (hereinafter also referred to as GPC) will be described.

  Specifically, the following procedure is performed. First, 1 ml of tetrahydrofuran solvent is added to 1 mg of the measurement resin, and the mixture is stirred at room temperature using a magnetic stirrer, etc., and the resin is sufficiently dissolved and filtered through a membrane filter having a pore size of 0.45 to 0.50 μm. To prepare a sample for GPC measurement. Next, after the GPC measurement column is heated and stabilized at 40 ° C., tetrahydrofuran is flowed at a rate of 1 ml per minute, and 100 μl of a measurement sample having a concentration of 1 mg / ml is injected and measured. The measurement column is preferably used in combination with a commercially available polystyrene gel column. For example, a combination of Shodex GPC KF-801, 802, 803, 804, 806, 807 manufactured by Showa Denko KK, a combination of TSKgel G1000H, G2000H, G3000H, G4000H, G5000H, G6000H, G7000H, TSK guard column manufactured by Tosoh Corporation, etc. Can be mentioned. As a detector, a refractive index detector (IR detector) or a UV detector may be used.

  The number average molecular weight and the weight average molecular weight of the tetrahydrofuran-soluble component in the resin fine particles are expressed in terms of styrene resin equivalent molecular weight. The molecular weight in terms of styrene resin is determined from a styrene calibration curve. A styrene calibration curve may be prepared by measuring about 10 monodisperse polystyrene standard resins.

  Next, materials (raw materials) that can be used for the toner according to the present invention will be described.

(Binder resin)
The binder resin constituting the resin particles is prepared by polymerizing a polymerizable monomer. Examples of the polymerizable monomer used for polymerization include a polymerizable monomer having a carboxyl group and a polymerizable monomer used in combination with the polymerizable monomer having a carboxyl group.

  Specifically, as a polymerizable monomer having a carboxyl group, methyl methacrylate, ethyl methacrylate, n-butyl methacrylate, isopropyl methacrylate, isobutyl methacrylate, t-butyl methacrylate, n-octyl methacrylate, Methacrylic acid ester derivatives such as 2-ethylhexyl methacrylate, stearyl methacrylate, lauryl methacrylate, phenyl methacrylate, diethylaminoethyl methacrylate, dimethylaminoethyl methacrylate, methyl acrylate, ethyl acrylate, isopropyl acrylate, acrylic acid n -Butyl, t-butyl acrylate, isobutyl acrylate, n-octyl acrylate, 2-ethylhexyl acrylate, stearyl acrylate, lauryl acrylate, phenyl acrylate, etc. Le ester derivatives, acrylonitrile, methacrylonitrile, acrylic acid or methacrylic acid derivatives such as acrylamide.

  Moreover, as a polymerizable monomer used in combination with a polymerizable monomer having a carboxyl group, styrene, o-methylstyrene, m-methylstyrene, p-methylstyrene, α-methylstyrene, p-phenylstyrene, p -Ethyl styrene, 2,4-dimethyl styrene, p-tert-butyl styrene, pn-hexyl styrene, pn-octyl styrene, pn-nonyl styrene, pn-decyl styrene, pn- Styrene or styrene derivatives such as dodecylstyrene, olefins such as ethylene, propylene and isobutylene, vinyl esters such as vinyl propionate, vinyl acetate and vinyl benzoate, vinyl ethers such as vinyl methyl ether and vinyl ethyl ether, vinyl methyl Ketone, vinyl ethyl ketone, vinyl hex Vinyl ketones such as ketones, N- vinylcarbazole, N- vinyl indole, N- vinyl compounds such as N- vinylpyrrolidone, vinyl naphthalene, and vinyl compounds such as vinyl pyridine.

  Further, it is more preferable to use a combination of monomers having an ionic dissociation group as the polymerizable monomer constituting the resin. For example, it has a substituent such as a carboxyl group, a sulfonic acid group, and a phosphoric acid group as a constituent group of the monomer. Specifically, acrylic acid, methacrylic acid, maleic acid, itaconic acid, cinnamic acid, fumar Examples include acid, maleic acid monoalkyl ester, itaconic acid monoalkyl ester, styrene sulfonic acid, allyl sulfosuccinic acid, 2-acrylamido-2-methylpropane sulfonic acid, and acid phosphooxyethyl methacrylate.

  Furthermore, polyfunctionality such as divinylbenzene, ethylene glycol dimethacrylate, ethylene glycol diacrylate, diethylene glycol dimethacrylate, diethylene glycol diacrylate, triethylene glycol dimethacrylate, triethylene glycol diacrylate, neopentyl glycol dimethacrylate, neopentyl glycol diacrylate, etc. It is also possible to use a crosslinkable resin by using a functional vinyl.

  In addition, when producing binder resin by an emulsion association method, it is possible to use a water-soluble radical polymerization initiator, for example. Examples of the water-soluble polymerization initiator include persulfates such as potassium persulfate and ammonium persulfate, azobisaminodipropane acetate, azobiscyanovaleric acid and its salts, hydrogen peroxide, and the like.

(Coloring agent)
As the colorant used in the present invention, a known inorganic or organic colorant can be used. Specific colorants are shown below.

  Examples of the black colorant include carbon black such as furnace black, channel black, acetylene black, thermal black, and lamp black, and magnetic powder such as magnetite and ferrite.

  Examples of the colorant for magenta or red include C.I. I. Pigment red 2, C.I. I. Pigment red 3, C.I. I. Pigment red 5, C.I. I. Pigment red 6, C.I. I. Pigment red 7, C.I. I. Pigment red 15, C.I. I. Pigment red 16, C.I. I. Pigment red 48; 1, C.I. I. Pigment red 53: 1, C.I. I. Pigment red 57: 1, C.I. I. Pigment red 122, C.I. I. Pigment red 123, C.I. I. Pigment red 139, C.I. I. Pigment red 144, C.I. I. Pigment red 149, C.I. I. Pigment red 166, C.I. I. Pigment red 177, C.I. I. Pigment red 178, C.I. I. And CI Pigment Red 222.

  Examples of the colorant for orange or yellow include C.I. I. Pigment orange 31, C.I. I. Pigment orange 43, C.I. I. Pigment yellow 12, C.I. I. Pigment yellow 13, C.I. I. Pigment yellow 14, C.I. I. Pigment yellow 15, C.I. I. Pigment yellow 74, C.I. I. Pigment yellow 93, C.I. I. Pigment yellow 94, C.I. I. And CI Pigment Yellow 138.

  Examples of the colorant for green or cyan include C.I. I. Pigment blue 15, C.I. I. Pigment blue 15; 2, C.I. I. Pigment blue 15; 3, C.I. I. Pigment blue 15; 4, C.I. I. Pigment blue 16, C.I. I. Pigment blue 60, C.I. I. Pigment blue 62, C.I. I. Pigment blue 66, C.I. I. And CI Pigment Green 7.

  These colorants may be used alone or in combination of two or more as required. The addition amount of the colorant is set in the range of 1 to 30% by mass, preferably 2 to 20% by mass with respect to the whole toner.

(Chain transfer agent)
In order to adjust the molecular weight of the resin, a commonly used chain transfer agent can be used. The chain transfer agent used is not particularly limited. For example, mercaptans such as n-octyl mercaptan, n-decyl mercaptan, tert-dodecyl mercaptan, and mercaptopropionate esters such as n-octyl-3-mercaptopropionate. , Terpinolene and α-methylstyrene dimer are used.

(wax)
A known compound can be used for the wax used in the present invention.

  As such, for example, polyolefin wax such as polyethylene wax and polypropylene wax, long chain hydrocarbon wax such as paraffin wax and sazol wax, dialkyl ketone wax such as distearyl ketone, carnauba wax, montan wax, Trimethylolpropane tribehenate, pentaerythritol tetrabehenate, pentaerythritol tetrastearate, pentaerythritol diacetate dibehenate, glycerin tribehenate, 1,18-octadecanediol distearate, tristearyl trimellitic acid , Ester waxes such as distearyl maleate, amide waxes such as ethylenediamine behenyl amide, trimellitic acid tristearyl amide, etc. It is.

  The amount of wax contained in the toner is preferably 1 to 20% by mass, and more preferably 3 to 15% by mass with respect to the total toner.

(Charge control agent)
A charge control agent can be added to the toner according to the present invention as necessary. A known compound can be used as the charge control agent.

(External additive)
Examples of inorganic particles that can be used as an external additive include conventionally known particles. Specifically, silica fine particles, titania fine particles, alumina fine particles, and complex oxides thereof can be preferably used. These inorganic particles are preferably hydrophobic.

  Examples of the organic fine particles that can be used as the external additive include spherical fine particles having a number average primary particle diameter of about 10 to 2000 nm. Examples of the constituent material of the organic fine particles include polystyrene, polymethyl methacrylate, and styrene-methyl methacrylate copolymer.

  The toner according to the present invention can be used as a one-component developer or a two-component developer.

  When used as a one-component developer, it can be used as a non-magnetic one-component developer or a magnetic one-component developer containing about 0.1 to 0.5 μm of magnetic particles in a toner.

  It is also possible to use a two-component developer using a carrier. As the carrier, conventionally known magnetic particles such as metals such as iron, ferrite, and magnetite, and alloys of these metals with metals such as aluminum and lead can be used. Ferrite particles are particularly preferable. The particle diameter of the carrier is preferably 20 to 100 μm, and more preferably 25 to 80 μm.

  The particle diameter of the carrier can be typically measured by a laser diffraction particle size distribution measuring apparatus “HELOS” (manufactured by SYMPATEC) equipped with a wet disperser.

  The carrier is preferably a carrier in which magnetic particles are further coated with a resin, or a so-called resin dispersion type carrier in which magnetic particles are dispersed in a resin. The coating resin is not particularly limited, and for example, an olefin resin, a styrene resin, a styrene-acrylic resin, a silicon resin, an ester resin, a fluorine-containing polymer resin, or the like is used. In addition, the resin for constituting the resin-dispersed carrier is not particularly limited, and a known resin can be used. For example, a styrene-acrylic resin, a polyester resin, a fluorine resin, a phenol resin, or the like is used. be able to. Among these, a coat carrier coated with a styrene-acrylic resin is more preferable because it can prevent the external additive from being detached and ensure durability.

  Next, an image forming apparatus capable of forming an image with the toner will be described.

  FIG. 1 is a schematic sectional view showing an example of an image forming apparatus in which the toner can be used.

  In FIG. 1, 1Y, 1M, 1C and 1K are photosensitive members, 4Y, 4M, 4C and 4K are developing means, 5Y, 5M, 5C and 5K are primary transfer rolls as primary transfer means, and 5A is a secondary transfer. Secondary transfer rolls as means, 6Y, 6M, 6C and 6K are cleaning means, 7 is an intermediate transfer member unit, 24 is a heat roll type fixing device, and 70 is an intermediate transfer member.

  This image forming apparatus is called a tandem color image forming apparatus, and includes a plurality of sets of image forming units 10Y, 10M, 10C, and 10K, an endless belt-shaped intermediate transfer body unit 7 as a transfer unit, and a recording member P. An endless belt-shaped sheet feeding / conveying means 21 and a heat roll type fixing device 24 as a fixing means. A document image reading device SC is disposed on the upper part of the main body A of the image forming apparatus.

  As one of the different color toner images formed on each photoconductor, an image forming unit 10Y that forms a yellow image includes a drum-shaped photoconductor 1Y as a first photoconductor, and a periphery of the photoconductor 1Y. A charging unit 2Y, an exposure unit 3Y, a developing unit 4Y, a primary transfer roll 5Y as a primary transfer unit, and a cleaning unit 6Y. An image forming unit 10M that forms a magenta image as another different color toner image is disposed around a drum-shaped photoconductor 1M as a first photoconductor, and the photoconductor 1M. A charging unit 2M, an exposure unit 3M, a developing unit 4M, a primary transfer roll 5M as a primary transfer unit, and a cleaning unit 6M. In addition, an image forming unit 10C that forms a cyan image as one of other different color toner images is disposed around the photoconductor 1C as a drum-type photoconductor 1C as a first photoconductor. The charging unit 2C, the exposure unit 3C, the developing unit 4C, the primary transfer roll 5C as the primary transfer unit, and the cleaning unit 6C are provided. Further, an image forming unit 10K that forms a black image as one of other different color toner images is disposed around a drum-shaped photosensitive member 1K as a first photosensitive member, and the photosensitive member 1K. It has a charging means 2K, an exposure means 3K, a developing means 4K, a primary transfer roll 5K as a primary transfer means, and a cleaning means 6K.

  The endless belt-like intermediate transfer body unit 7 has an endless belt-like intermediate transfer body 70 as an intermediate transfer endless belt-like second image carrier that is wound around a plurality of rolls and is rotatably supported.

  Each color image formed by the image forming units 10Y, 10M, 10C, and 10K is sequentially transferred onto the rotating endless belt-shaped intermediate transfer body 70 by the primary transfer rolls 5Y, 5M, 5C, and 5K, and is combined. A colored image is formed. A recording member P such as a sheet as a transfer material accommodated in the sheet feeding cassette 20 is fed by the sheet feeding / conveying means 21, passes through a plurality of intermediate rolls 22 A, 22 B, 22 C, 22 D, and a registration roll 23, and is secondary. A color image is transferred onto the recording member P at a time by being conveyed to a secondary transfer roll 5A as a transfer means. The recording member P to which the color image has been transferred is fixed by the heat roll type fixing device 24, is sandwiched by the paper discharge roll 25, and is placed on the paper discharge tray 26 outside the apparatus.

  On the other hand, after the color image is transferred to the recording member P by the secondary transfer roll 5A, the residual toner is removed from the endless belt-shaped intermediate transfer body 70 from which the recording member P is separated by the curvature by the cleaning means 6A.

  During the image forming process, the primary transfer roll 5K is always in pressure contact with the photoreceptor 1K. The other primary transfer rolls 5Y, 5M, and 5C are in pressure contact with the corresponding photoreceptors 1Y, 1M, and 1C, respectively, only during color image formation.

  The secondary transfer roll 5A is pressed against the endless belt-shaped intermediate transfer body 70 only when the recording member P passes through the secondary transfer roll 5A and the secondary transfer is performed.

  Further, the housing 8 can be pulled out from the apparatus main body A through the support rails 82L and 82R.

  The housing 8 includes image forming units 10Y, 10M, 10C, and 10K, and an endless belt-shaped intermediate transfer body unit 7.

  The image forming units 10Y, 10M, 10C, and 10K are arranged in tandem in the vertical direction. An endless belt-shaped intermediate transfer body unit 7 is disposed on the left side of the photoreceptors 1Y, 1M, 1C, and 1K in the figure. The endless belt-shaped intermediate transfer body unit 7 includes an endless belt-shaped intermediate transfer body 70 that can be rotated by winding rolls 71, 72, 73, 74, and 76, primary transfer rolls 5Y, 5M, 5C, and 5K, and a cleaning unit. 6A.

  The image forming units 10Y, 10M, 10C, and 10K and the endless belt-shaped intermediate transfer body unit 7 are integrally pulled out from the main body A by the drawer operation of the housing 8.

  In this way, toner images are formed on the photoreceptors 1Y, 1M, 1C, and 1K by charging, exposure, and development, and the toner images of the respective colors are superimposed on the endless belt-shaped intermediate transfer body 70, and are collectively applied to the recording member P The image is transferred, and fixed by pressing and heating with a heat roll type fixing device 24 and fixed. The photoreceptors 1Y, 1M, 1C, and 1K after transferring the toner image to the recording member P are cleaned with the cleaning device 6A to remove the toner remaining on the photoreceptor, and then the above-described charging, exposure, and development cycle. The next image formation is performed.

  FIG. 2 shows an example of a full-color image forming apparatus using the toner according to the present invention as a non-magnetic one-component developer.

  FIG. 2 is a schematic sectional view showing an example of a full-color image forming apparatus.

  In the full-color image forming apparatus shown in FIG. 2, a charging brush 111 that uniformly charges the surface of the photosensitive drum 10 to a predetermined potential around the photosensitive drum 10 that is rotationally driven, and the photosensitive drum 10 A cleaner 112 for scraping off the remaining toner is provided.

  Further, a laser scanning optical system 20 for scanning and exposing the photosensitive drum 10 charged by the charging brush 111 with a laser beam is provided. The laser scanning optical system 20 includes a laser diode, a polygon mirror, and an fθ optical element. As is well known, print data for each of yellow, magenta, cyan, and black is transferred from the host computer to the control unit. The laser scanning optical system 20 sequentially outputs the laser beam as a laser beam based on the print data for each color, scans and exposes the photosensitive drum 10, and thereby the static image for each color is formed on the photosensitive drum 10. Electro latent images are sequentially formed.

  In addition, the full-color developing device 30 that supplies full-color development to the photosensitive drum 10 on which the electrostatic latent image is formed in this manner, performs yellow, magenta, cyan, and black around the support shaft 33. Four color-developing units 31Y, 31M, 31C, and 31Bk each containing non-magnetic one-component toner are provided. The developing units 31Y, 31M, 31C, and 31Bk rotate around the support shaft 33, and the developing units 31Y, 31M, 31C, and 31Bk are rotated. It is guided to a position facing the photosensitive drum 10.

  Further, in each of the developing devices 31Y, 31M, 31C, and 31Bk in the full-color developing device 30, as shown in FIG. 2, the toner is formed on the outer peripheral surface of the developer carrying member (developing roller) 32 that rotates and conveys the toner. A regulating member is in pressure contact, and the toner regulating member regulates the amount of toner conveyed by the developing roller 32 and charges the conveyed toner. In the full-color developing device 30, two toner regulating members may be provided in order to appropriately regulate and charge the toner conveyed by the developing roller.

  Then, whenever the electrostatic latent image of each color is formed on the photosensitive drum 10 by the laser scanning optical system 20 as described above, the full-color developing device 30 is rotated around the support shaft 33 as described above. Then, the developing devices 31Y, 31M, 31C, and 31Bk containing toner of the corresponding colors are sequentially guided to positions facing the photosensitive drum 10, and the developing rollers 32 in the developing devices 31Y, 31M, 31C, and 31Bk are moved. Development is performed by sequentially supplying charged toner of each color onto the photosensitive drum 10 in which the electrostatic latent images of each color are sequentially formed as described above in contact with the photosensitive drum 10. It has become.

  Further, an endless intermediate transfer belt 40 that is rotationally driven is provided as an intermediate transfer body 40 at a position downstream of the full-color developing device 30 in the rotation direction of the photosensitive drum 10. Is driven to rotate in synchronization with the photosensitive drum 10. The intermediate transfer belt 40 is pressed by a rotatable primary transfer roller 41 so as to come into contact with the photosensitive drum 10, and a portion of a support roller 42 that supports the intermediate transfer belt 40 includes: A secondary transfer roller 43 is rotatably provided, and the recording material S such as recording paper is pressed against the intermediate transfer belt 40 by the secondary transfer roller 43.

  Further, a cleaner 50 that scrapes off the toner remaining on the intermediate transfer belt 40 is provided in a space between the full-color developing device 30 and the intermediate transfer belt 40 so as to be able to contact with and separate from the intermediate transfer belt 40. ing.

  Further, the paper feeding means 60 that guides the recording material S such as plain paper to the intermediate transfer belt 40 includes a paper feeding tray 61 that accommodates the recording material S and the recording material S that is accommodated in the paper feeding tray 61 one by one. The recording material S fed in synchronization with the paper feed roller 62 for feeding paper and the image formed on the intermediate transfer belt 40 is sent between the intermediate transfer belt 40 and the secondary transfer roller 43. The recording material S sent between the intermediate transfer belt 40 and the secondary transfer roller 43 in this way is pressed against the intermediate transfer belt 40 by the secondary transfer roller 43. The toner image is pressed and transferred from the intermediate transfer belt 40 to the recording material S.

  On the other hand, the recording material S on which the toner image is pressed and transferred as described above is guided to the fixing device 70 by the conveying means 66 constituted by an air suction belt or the like, and is transferred by the fixing device 70. The toner image is fixed on the recording material S, and then the recording material S is discharged onto the upper surface of the apparatus main body 100 through the vertical conveyance path 80.

  Next, the operation of forming a full color image using this full color image forming apparatus will be specifically described.

  First, the photosensitive drum 10 and the intermediate transfer belt 40 are rotationally driven in the respective directions at the same peripheral speed, and the photosensitive drum 10 is charged to a predetermined potential by the charging brush 11.

  The photosensitive drum 10 thus charged is exposed to a yellow image by the laser scanning optical system 20 to form an electrostatic latent image of a cyan image on the photosensitive drum 10. The yellow image is developed by supplying the yellow toner charged by the toner regulating member as described above from the developing device 31Y in which the yellow toner is accommodated in the photosensitive drum 10, and the yellow toner image is thus formed. The intermediate transfer belt 40 is pressed against the body drum 10 by the primary transfer roller 41, and the yellow toner image formed on the photosensitive drum 10 is primarily transferred to the intermediate transfer belt 40.

  After the yellow toner image is transferred to the intermediate transfer belt 40 in this way, the full-color developing device 30 is rotated around the support shaft 33 as described above, and the developing device 31M containing magenta toner is exposed to light. As in the case of the yellow image described above, the magenta image is exposed to the photosensitive drum 10 charged by the laser scanning optical system 20 to form an electrostatic latent image. The electrostatic latent image is developed by a developing device 31M containing magenta toner, and the developed magenta toner image is primarily transferred from the photosensitive drum 10 to the intermediate transfer belt 40. Black image exposure, development and primary transfer are sequentially performed, and yellow, magenta, cyan, and black toner images are sequentially superimposed on the intermediate transfer belt 40. To form a toner image of Rukara.

  When the final black toner image is primarily transferred onto the intermediate transfer belt 40, the recording material S is fed between the secondary transfer roller 43 and the intermediate transfer belt 40 by the timing roller 63, and the secondary transfer roller. The recording material S is pressed against the intermediate transfer belt 40 by 43, and the full color toner image formed on the intermediate transfer belt 40 is secondarily transferred onto the recording material S.

  When the full-color toner image is secondarily transferred onto the recording material S in this way, the recording material S is guided to the fixing device 70 by the conveying means 66, and the full-color toner transferred by the fixing device 70 is transferred. The image is fixed on the recording material S, and then the recording material S is discharged onto the upper surface of the apparatus main body 1 through the vertical conveyance path 80.

  The embodiments of the present invention will be specifically described below with reference to examples, but the present invention is not limited thereto.

<Preparation of resin particle dispersion 1>
In a separable flask equipped with a stirrer, a temperature sensor, a cooling pipe, a nitrogen introducing device, and a stirrer, 97.0 parts by mass of sodium dodecyl sulfate aqueous solution (2.6 parts by mass of active ingredient) is 1510 parts by mass of ion-exchanged water. To prepare “Aqueous medium 1”. Thereafter, a mixed solution composed of the following components was added to the “aqueous medium 1”.

Styrene 213 parts by mass n-butyl acrylate 62 parts by mass Acrylic acid 7 parts by mass Pentaerythritol tetrastearate 154 parts by mass Thereafter, an initiator solution having the following constitution was added, and the temperature was raised to 82.5 ° C. for 2 hours. To carry out the polymerization reaction.

Hydrogen peroxide aqueous solution (active ingredient 2.5 parts by mass) 42 parts by mass Potassium erythorbate aqueous solution (active ingredient 6.5 parts by mass) 42 parts by mass n-octyl mercaptan 0.6 parts by mass
Styrene 542 parts by weight n-butyl acrylate 157 parts by weight A monomer mixture consisting of 18 parts by weight of acrylic acid was added, followed by
Hydrogen peroxide aqueous solution (active ingredient 9 parts by mass) 145 parts by mass Potassium erythorbate aqueous solution (active ingredient 23.5 parts by mass) 153 parts by mass An initiator solution consisting of 8.2 parts by mass of n-octyl mercaptan was added. Further, 48 parts by mass of an aqueous sodium dodecyl sulfate solution (4.8 parts by mass of active ingredient) was added, the temperature was raised to 90 ° C., and the polymerization reaction was carried out with stirring for 1 hour to prepare a resin particle dispersion. This was designated as “resin particle dispersion 1”.

<Preparation of colorant dispersion>
The colorant dispersion is C.I. as a magenta colorant. I. Pigment Red 122 was dispersed in ion-exchanged water to a solid content concentration of 12.5% by mass to prepare an aqueous dispersion. This was designated as “colorant dispersion”.

<Production of toner>
<Preparation of Toner 1>
"Resin particle dispersion 1" 1700 parts by mass (converted to solid content), ion exchange water 2100 parts by mass, "colorant dispersion" 250 parts by mass, thermometer, condenser, nitrogen introduction device, and stirrer Into a separate separable flask. Further, an aqueous sodium hydroxide solution (25% by mass) was added while maintaining the temperature at 30 ° C. to adjust the pH to 10.

Next, an aqueous solution in which 54.3 parts by mass of magnesium chloride hexahydrate is dissolved in 104.3 parts by mass of ion-exchanged water is added, and then the temperature inside the system is raised to 75 ° C. The aggregation reaction of the colorant particles was started. After the start of aggregation, the median diameter (D ₅₀ ) and circularity on the volume basis of the particles were measured using a particle size distribution measuring device “Multisizer 3” (manufactured by Beckman Coulter, Inc.). When the median diameter (D ₅₀ ) on the volume basis reached 6.2 μm, 43.4 parts by mass of potassium pyrophosphate was added, and stirring was further continued.

  When the circularity of the particles reached 0.976, the temperature in the system was cooled to 30 ° C. to complete the aggregation reaction, and a “dispersed liquid of toner particle intermediate 1” was produced.

  The produced “dispersion of toner particle intermediate 1” was subjected to solid-liquid separation with a basket-type centrifuge “MARK III type (model number 60 × 40)” (manufactured by Matsumoto Kikai Manufacturing Co., Ltd.). A “wet cake” was formed, and the “wet cake of toner particle intermediate 1” was washed and filtered with washing water, and washed until the electrical conductivity of the filtrate was 10 μS / cm or less. The amount of washing water used for washing was 18 times the solid content of “wet cake of toner particle intermediate 1”. Thereafter, it is transferred to an air-flow dryer “flash jet dryer” (manufactured by Seishin Enterprise Co., Ltd.), and the washed toner particle intermediate is dried until the water content becomes 0.5 mass%. Was made. In addition, the airflow used at the time of a drying process used the thing of 40 degreeC and about 20% RH.

  After completion of the drying treatment, the obtained “toner particle intermediate 1” was subjected to 1% by mass of hydrophobic silica having a number average primary particle size of 12 nm, a hydrophobization degree of 68, and a number average primary particle size of 80 nm. Hydrophobic titanium oxide having a hydrophobization degree of 63 was added so as to be 1% by mass, and mixed using a “Henschel Miki mixer” (manufactured by Mitsui Miike Chemical Co., Ltd.). In this way, “Toner 1” was produced.

The produced “Toner 1” had a volume-based median diameter (D ₅₀ ) of 6.3 μm, a variation coefficient in the volume-based particle size distribution of 18, and a content of particles having a particle diameter of 10 μm or more was 5% by volume. .

<Preparation of Toner 2>
In the above-mentioned “toner particle intermediate 1”, when the median diameter on the volume basis of the particles became 5.3 μm, 22.0 parts by mass of potassium pyrophosphate and 23.0 parts by mass of pyrophosphate were added. “Toner 2” was prepared in the same procedure.

<Preparation of Toner 3>
In the above-mentioned “toner particle intermediate 1”, when the median diameter on the volume basis of the particles became 7.0 μm, “Toner 3” was prepared in the same procedure except that 45.0 parts by mass of sodium pyrophosphate was added. Produced.

<Preparation of Toner 4>
In the above-mentioned “toner particle intermediate 1”, when the median diameter on the volume basis of the particles became 6.3 μm, “Toner 4” was prepared in the same procedure except that 60.0 parts by mass of sodium pyrophosphate was added. Produced.

<Preparation of Toner 5>
In the above-mentioned “toner particle intermediate 1”, when the median diameter on the volume basis of the particles becomes 7.3 μm, 20.0 parts by mass of pyrophosphate, 21.0 parts by mass of potassium orthosilicate, and 20. “Toner 5” was prepared in the same procedure except that 0 part by mass was added.

<Preparation of Toner 6>
In the above-mentioned “toner particle intermediate 1”, when the median diameter on the volume basis of the particles became 6.1 μm, the same procedure was performed except that 38.5 parts by mass of potassium pyrophosphate and 28.0 parts by mass of sodium pyrophosphate were added. “Toner 6” was prepared by the procedure described above.

<Preparation of Toner 7>
In the aforementioned “toner particle intermediate 1”, when the median diameter on the volume basis of the particles became 5.4 μm, 35.5 parts by mass of potassium pyrophosphate and 36.5 parts by mass of sodium pyrophosphate were added. “Toner 7” was prepared in the same procedure. The amount of washing water used in the production of “Toner 7” was 22 times the solid-liquid amount of “wet cake of toner particle intermediate 7”, and the final conductivity value of the filtrate was 10 μS / cm or less. It became.

<Preparation of Toner 8>
In the above-mentioned “toner particle intermediate 1”, when the median diameter on the volume basis of the particles became 7.7 μm, 15.0 parts by mass of sodium pyrophosphate and 20.0 parts by mass of pyrophosphoric acid were added. “Toner 8” was prepared in the same procedure.

<Preparation of Toner 9>
In the aforementioned “toner particle intermediate 1”, when the median diameter on the volume basis of the particles became 2.9 μm, 53.0 parts by mass of sodium pyrophosphate and 80.0 parts by mass of pyrophosphate were added. “Toner 9” was prepared in the same procedure. The amount of washing water used in the production of “Toner 9” was 25 times the solid-liquid amount of “wet cake of toner particle intermediate 9”, and the final conductivity value of the filtrate was 10 μS / cm or less. It became.

<Preparation of Toner 10>
In the above-mentioned “toner particle intermediate 1”, when the median diameter on the volume basis of the particles became 3.0 μm, 100.0 parts by mass of sodium pyrophosphate and 80.0 parts by mass of pyrophosphate were added. “Toner 10” was prepared in the same procedure. The amount of washing water used in the production of “Toner 7” was 25 times the solid-liquid amount of “wet cake of toner particle intermediate 10”, and the final conductivity value of the filtrate was 10 μS / cm or less. It became.

<Preparation of Toner 11>
In the above “toner particle intermediate 1”, when the median diameter on the volume basis of the particles becomes 7.0 μm, 4.0 parts by mass of pyrophosphoric acid, 20.0 parts by mass of sodium orthosilicate, and sodium orthoborate “Toner 11” was prepared in the same procedure except that 20.0 parts by mass were added.

<Preparation of Toner 12>
In the above-mentioned “toner particle intermediate 1”, when the median diameter on the volume basis of the particles becomes 6.1 μm, 5.0 parts by mass of potassium pyrophosphate and 22.1 parts by mass of pyrophosphate are added. “Toner 12” was prepared in the same procedure.

<Preparation of Toner 13>
In the above-mentioned “toner particle intermediate 1”, when the median diameter on the volume basis of the particles became 6.2 μm, 25.0 parts by mass of potassium orthosilicate and 23.0 parts by mass of sodium orthoborate were added. “Toner 13” was prepared by the procedure described above.

<Preparation of Toner 14>
In the above-mentioned “toner particle intermediate 1”, “toner 14” was prepared by the same procedure except that 18.0 parts by mass of pyrophosphoric acid was added when the median diameter on the volume basis of the particles became 6.4 μm. did.

<Preparation of Toner 15>
In the above-mentioned “toner particle intermediate 1”, when the median diameter on the volume basis of the particles became 5.3 μm, 35.0 parts by mass of pyrophosphate and 1.5 parts by mass of sodium pyrophosphate were added. “Toner 15” was prepared in the same procedure.

<Preparation of Toner 16>
In the above-mentioned “toner particle intermediate 1”, when the median diameter on the volume basis of the particles became 5.2 μm, 80.0 parts by mass of pyrophosphoric acid and 11.0 parts by mass of potassium pyrophosphate were added. “Toner 16” was prepared in the same procedure.

<Preparation of Toner 17>
In the above-mentioned “toner particle intermediate 1”, when the median diameter on the volume basis of the particles is 6.9 μm, 75.0 parts by mass of pyrophosphate, 1.5 parts by mass of potassium pyrophosphate, 20 mg of sodium pyrophosphate “Toner 17” was prepared in the same manner except that 0.0 part by mass was added.

Table 1 shows the contents of phosphorus element, potassium element and sodium element of toners 1 to 17 produced, the median diameter (D ₅₀ ) based on volume, and the coefficient of variation based on volume. These values are measured and calculated by the method described above.

<Preparing a two-component developer>
“Toner 1-17” produced by using the magenta colorant described above was mixed with a ferrite carrier having a median diameter (D ₅₀ ) of 45 μm on a volume basis so that the toner concentration was 7% by mass. 1-17 "were prepared.

<Evaluation>
<Image forming device>
As an image forming apparatus for evaluation, a commercially available digital color multifunction peripheral “Bizhub C300” (manufactured by Konica Minolta Business Technologies) was used, and only magenta toner was output for evaluation.

<Evaluation item>
(Changes in toner charge amount depending on storage environment)
The toner charge amount varies depending on the storage environment. The developer used in Examples 1 to 12 and Comparative Examples 1 to 5 is stored in a high temperature and high humidity (30 ° C., 80% RH) environment for 24 hours, and then charged. The amount was measured. After that, it was stored in a low temperature and low humidity (10 ° C., 20% RH) environment, and the charge amount was measured when the temperature and humidity inside the cartridge reached 10 ° C., 20% RH. Table 2 shows the charge amount difference (ΔμC / g) of the developer. The charge amount of the toner was measured by the following measuring method using a blow-off type charge amount measuring device “TB-200” (manufactured by Toshiba).

Blow-off type charge measuring device “TB-200” (manufactured by Toshiba) equipped with a 400 mesh stainless steel screen is blown with nitrogen gas for 10 seconds under the condition of blow pressure 4.9 × 10 ⁴ Pa. The charge amount (μC / g) is calculated by dividing the measured charge by the flying toner mass.

  The difference in charge amount (ΔμC / g) between a high temperature and high humidity (30 ° C., 80% RH) environment and a low temperature and low humidity (10 ° C., 20% RH) environment was 35 μC / g or less.

(Evaluation of image density due to changes in print creation environment)
The printing environment is a high-quality, high-quality paper (65g) in a high-temperature, high-humidity (30 ° C, 80% RH) environment and a low-temperature, low-humidity (10 ° C, 20% RH) environment. / m ²⁾ was printed on, the difference in image density from the obtained print image (.DELTA.Dmax) was calculated. The image density was determined by measuring the density of the solid magenta image portion at 12 points using a reflection densitometer “RD-918” (manufactured by Macbeth), and taking the average value.

Evaluation criteria A: Excellent image density difference (ΔDmax) between high temperature and high humidity and low temperature and low humidity is less than 0.01 ○: Image density difference (ΔDmax) between high temperature and high humidity and low temperature and low humidity is 0.01 or more, 0.04 Good if less than x: Poor when the image density difference (ΔDmax) between high temperature and high humidity and low temperature and low humidity is 0.04 or more.

(Evaluation of image density accompanying printing durability)
The image density evaluation accompanying printing durability was evaluated based on the print image density at the start of print production and when 10,000 continuous prints were completed.

Specifically, under the environmental conditions of low temperature and low humidity (10 ° C, 20% RH), 10,000 continuous prints were made on high-quality A4 size paper (65 g / m ² ). The image density of the solid magenta image area at the end was measured. The image density was determined by measuring the density of the solid magenta image portion at 12 points using a reflection densitometer “RD-918” (manufactured by Macbeth), and taking the average value.

Evaluation Criteria A: The difference in image density at the start of printing and the end of printing 10,000 sheets is less than 0.01, and the printing durability is excellent. ○: The difference in image density at the start of printing and the end of printing 10,000 sheets is 0. .01 or more and less than 0.04, good printing durability ×: Image printing density difference between the start of print production and the end of 10,000-sheet printing is 0.04 or more, resulting in poor printing durability.

  Table 2 shows the evaluation results.

  As shown in Table 2, “Examples 1 to 12” having the configuration of the present invention obtained favorable results for all evaluation items, whereas “Comparative Examples 1 to 5” deviating from the configuration of the present invention. No satisfactory results were obtained for any of the evaluation items.

FIG. 2 is a schematic cross-sectional view illustrating an example of an image forming apparatus that can use the toner. It is a schematic sectional drawing which shows an example of a full-color image forming apparatus.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Semiconductor laser light source 2 Polygon mirror 3 f (theta) lens 4 Photosensitive drum 5 Charging device 6 Developing device 7 Transfer device 9 Separator (separation pole)
P transfer material 10 fixing device 11 cleaning device 12 pre-charge exposure (PCL)
13 Cleaning blade

Claims (3)

An electrostatic charge image developing toner containing at least a binder resin, a colorant, a phosphorus (P) element, and a potassium (K) element,
The binder resin is a resin containing a carboxyl group,
50 ppm or more and 3000 ppm or less of phosphorus (P) element,
A toner for developing an electrostatic charge image, comprising 300 ppm or more and 4000 ppm or less of a potassium (K) element. An electrostatic charge image developing toner containing at least a binder resin, a colorant, a phosphorus (P) element, and a sodium (Na) element,
The binder resin is a resin containing a carboxyl group,
50 ppm or more and 3000 ppm or less of phosphorus (P) element,
A toner for developing an electrostatic charge image, comprising a sodium (Na) element in a range of 150 ppm to 2300 ppm. An electrostatic charge image developing toner containing at least a binder resin, a colorant, a phosphorus (P) element, a potassium (K) element, and a sodium (Na) element,
The binder resin is a resin containing a carboxyl group,
50 ppm or more and 3000 ppm or less of phosphorus (P) element,
A potassium (K) element of 300 ppm to 4000 ppm,
A toner for developing an electrostatic charge image, comprising a sodium (Na) element in a range of 150 ppm to 2300 ppm.

Images