JP2010210862A - Toner for electrostatic charge image development, and method of manufacturing toner for electrostatic charge image development - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a toner for electrostatic charge image development capable of allowing low temperature fixing and showing no fluctuation in the glossiness of toner images when continuous printing is carried out. <P>SOLUTION: The toner is a capsule toner comprising core particles and shell layers. The core particles are produced by mixing and agitating a dispersion liquid of colorant particles, a resin dispersion liquid (A) having Mw of 10,000 to 30,000, a softening point of 80 to 100°C, and Tg of 30 to 40°C, a resin dispersion (B) having Mw of 250,000 to 350,000, a softening point of 140 to 160°C and Tg of 60 to 80°C, and an aqueous solution of magnesium chloride, and heating, associating and fusing the mixture. To the dispersion liquid of the core particles, a dispersion liquid (C) having Mw of 5,000 to 20,000, a softening point of 100 to 120°C and Tg of 45 to 55°C and an aqueous solution of magnesium chloride are added and deposited on the surfaces of the core particles to form the shell layers. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a toner for developing an electrostatic charge image (hereinafter simply referred to as toner) used in an electrophotographic image forming apparatus and a method for producing a toner for developing electrostatic charge image (hereinafter also simply referred to as a toner production method). )

  In recent years, in an electrophotographic image forming apparatus, energy saving of a fixing device, which is said to have a large proportion of power consumption, has been promoted. For example, measures such as zero power consumption in a standby state are taken. It has been. As one of the technologies for realizing energy saving of such a fixing device, there is a toner fixing at a low temperature, and if it is a toner compatible with a low temperature fixing, a print can be produced from a standby state through a short warm-up time. Expected. However, in order to achieve low-temperature fixing, it is necessary to set the glass transition temperature of the resin constituting the toner to be low, so that the heat-resistant storage property of the toner is lowered. That is, a phenomenon of blocking in which toners stored in the storage state are fixed and aggregated by the action of temperature is likely to occur. Therefore, a so-called core-shell toner having a structure in which the surface of resin particles having a low glass transition temperature for low-temperature fixing is coated with a resin having a higher glass transition temperature has been proposed (for example, see Patent Document 1).

  In addition, recent digital image processing technology and toner diameter reduction technology enable high-resolution image formation with an electrophotographic image forming apparatus. As a result, it is possible to quickly provide high-quality prints without the hassle of printing, which was essential in conventional printing, and it is also possible to accept small-scale print orders on the order of hundreds to thousands of sheets. In particular, it has become active in the light printing field. Among such printed materials produced in the light printing field, there are also printed materials having a high glossiness typified by photographic images. In order to produce a toner image having a high glossiness, a resin constituting the toner It was necessary to lower the molecular weight in addition to the glass transition temperature. That is, it is required to form a smooth toner image surface when melted during fixing.

  However, the toner having a low glass transition temperature and molecular weight of the constituent resin has a low viscosity of the toner melted at the time of fixing, and also the internal cohesive force of the melted toner layer is reduced. There was a tendency to generate hot offset that causes fouling of fixing rolls and the like. In addition, when continuous printing is performed, there may be a difference in gloss between the first and last prints, leaving a problem in terms of maintaining a stable gloss level.

  From such a background, a combination of toner composed of a crystalline resin as a main component and a fixing device including a heat fixing roll and an endless belt is used to achieve both low temperature fixability and hot offset resistance. An image forming method has been proposed. This technique is intended to control the glossiness (gloss) of the toner image with the above configuration (see, for example, Patent Document 2). Although the technology of the above-mentioned patent document can confirm that the low-temperature fixability and the hot offset resistance are compatible and the image glossiness is widely controlled, it is possible to maintain the glossiness of the image without variation when continuous printing is performed. There was no description or suggestion. The technology of the above-mentioned patent document is specialized for belt fixing, and when the disclosed toner is combined with a fixing device having a configuration other than the fixing device disclosed in the patent document, the low-temperature fixing property and the offset resistance are reduced. It was not known from the contents of the literature whether or not both can be achieved.

JP 2002-116574 A JP 2003-29463 A

  The present invention is capable of so-called low-temperature fixing in which a toner image is fixed at a temperature lower than that of the prior art, and electrostatic image development without causing variation in the glossiness of the toner image formed during continuous printing. It is an object to provide a toner. In addition, the present invention can prevent contamination caused by adhesion of toner to transfer paper, a fixing roll, etc. by imparting appropriate strength to the melted toner to prevent breakage of the toner layer during fixing. An object of the present invention is to provide a toner for developing an electrostatic image having excellent offset resistance.

The present inventor has found that the above-described problem can be solved by any of the configurations described below. That is,
1. In an electrostatic charge image developing toner containing at least a binder resin, a colorant, and a wax,
The binder resin is
A resin (A) having a weight average molecular weight of 10,000 to 30,000, a softening point of 80 ° C. to 100 ° C., and a glass transition temperature of 30 ° C. to 40 ° C .;
A resin (B) having a mass average molecular weight of 250,000 to 350,000, a softening point of 140 ° C. to 160 ° C., and a glass transition temperature of 60 ° C. to 80 ° C .;
It is composed of a resin (C) having a mass average molecular weight of 5,000 to 20,000, a softening point of 100 ° C. to 120 ° C., and a glass transition temperature of 45 ° C. to 55 ° C. Toner for developing electrostatic image.

2. The electrostatic image developing toner has a core-shell structure,
A binder resin composed of the resin (A) and the resin (B), a core composed of a colorant and a wax, and a shell composed of the binder resin composed of the resin (C). 2. The toner for developing an electrostatic charge image as described in 1 above.

  3. 3. The electrostatic image developing toner according to 1 or 2 above, wherein the binder resin constituting the electrostatic image developing toner contains a vinyl resin.

4). In the method for producing a toner for developing an electrostatic image containing at least a binder resin, a colorant, and a wax,
At least resin particles containing a resin (A) having a weight average molecular weight of 10,000 to 30,000, a softening point of 80 ° C. to 100 ° C., and a glass transition temperature of 30 ° C. to 40 ° C .;
After aggregating the resin particles containing the resin (B) having a mass average molecular weight of 250,000 to 350,000, a softening point of 140 ° C. to 160 ° C., and a glass transition temperature of 60 ° C. to 80 ° C.,
Through the step of aggregating resin particles containing resin (C) having a mass average molecular weight of 5,000 to 20,000, a softening point of 100 ° C. to 120 ° C., and a glass transition temperature of 45 ° C. to 55 ° C. A method for producing a toner for developing an electrostatic image, comprising producing a toner for developing an electrostatic image.

5). After agglomerating the resin particles containing the resin (A) and the resin particles containing the resin (B) to form a core,
5. The electrostatic charge image development according to 4 above, wherein the core surface is formed by agglomerating resin particles containing the resin (C) to form a shell to produce a toner for electrostatic charge image development having a core-shell structure. Of manufacturing toner.

  According to the present invention, by using the above three types of resins (A), (B), and (C) as the binder resin constituting the toner, low-temperature fixing that fixes a toner image at a lower temperature than before is realized. As a result, it was found that the glossiness of the toner image does not vary during continuous printing. In addition, since the molten toner is imparted with an appropriate strength, the toner layer is not broken at the time of fixing, and the occurrence of hot offset that contaminates the transfer paper, the fixing roll and the like is eliminated.

1 is a schematic diagram illustrating an example of a tandem full-color image forming apparatus capable of two-component development type image formation.

(Technical idea of the present invention)
In the present invention, the resin (B) having a high molecular weight expresses a function like a filler with respect to other resins having a low molecular weight, so that viscosity and internal cohesive force are secured to some extent when the toner is melted, and the toner layer is broken. As a result, it is considered that the offset resistance is improved. That is, since the resin (B) has a higher molecular weight than other resins, it is difficult to be compatible with other resins, and it is considered that the resin (B) takes a form like a phase separation structure in the binder resin phase. By adopting such a form, it is considered that when the toner layer is melted, strength is imparted and breakage is avoided.

  Further, in the present invention, by setting the softening point and the glass transition temperature of the resin constituting the toner as described above, a good gloss image can be obtained even if the constituent resins have a difference in molecular weight. It is thought that. That is, by setting the softening point and glass transition temperature of the constituent resin as described above, the high molecular weight resin (B) does not always take the form of a phase separation structure with respect to other resins, and the fixing is completed. It is considered that the toner image is sufficiently heated until it is mixed and finally mixed with other resin, and a toner image with high glossiness is obtained.

  Hereinafter, the present invention will be described in detail.

(Description of Toner Constituent Resins (A), (B), (C))
First, three resins, resin (A), resin (B), and resin (C) constituting the binder resin of the toner according to the present invention will be described.

The binder resin constituting the toner according to the present invention is:
(1) Resin (A); a resin having a mass average molecular weight of 10,000 to 30,000, a softening point of 80 ° C. to 100 ° C., and a glass transition temperature of 30 ° C. to 40 ° C. (2) Resin (B) A resin having a mass average molecular weight of 250,000 to 350,000, a softening point of 140 ° C. to 160 ° C., and a glass transition temperature of 60 ° C. to 80 ° C. (3) Resin (C); 000 to 20,000, a softening point of 100 ° C. to 120 ° C., and a glass transition temperature of 45 ° C. to 55 ° C. Here, the mass average molecular weight is usually called a weight average molecular weight, and is an average molecular weight represented by Mw.

(Description of ratio of resin (A), (B), (C))
In the present invention, the resin (A) is 65% by mass to 94% by mass and the resin (B) is 1% by mass with respect to the ratio of the above-described resins (A), (B), and (C) constituting the binder resin. The content is preferably 20% by mass or less and the resin (C) is preferably 5% by mass or more and 15% by mass or less.

  As described above, the ratio of the resin (A) in the binder resin is preferably 65% by mass or more and 94% by mass or less, more preferably 70% by mass or more and 90% by mass or less, and still more preferably 75% by mass or more and 85% by mass. It is as follows. By setting the ratio of the resin (A) within the above range, mechanical properties and thermal properties of the resin (A) component described later act appropriately, and both low-temperature fixability and heat-resistant storage stability can be more reliably achieved. It seems to become like.

  As described above, the ratio of the resin (B) in the binder resin is preferably 1% by mass or more and 20% by mass or less, more preferably 2% by mass or more and 18% by mass or less, and further preferably 4% by mass or more. It is 16 mass% or less. By setting the ratio of the resin (B) within the above range, mechanical properties and thermal properties of the resin (B) component described later act appropriately, and it is easy to impart appropriate gloss on the formed toner image. It seems to be.

  As described above, the ratio of the resin (C) in the binder resin is preferably 5% by mass or more and 15% by mass or less, more preferably 6% by mass or more and 14% by mass or less, and further preferably 7% by mass or more. It is 13 mass% or less. By setting the ratio of the resin (C) within the above range, mechanical properties and thermal properties of the resin (C) component described later act appropriately, and both low temperature fixability and heat resistant storage stability can be more reliably achieved. It seems to become like.

(Description of mass average molecular weight, softening point temperature, glass transition temperature of resins (A), (B), and (C))
Next, the mass average molecular weight, softening point temperature, and glass transition temperature of the resins (A), (B), and (C) will be specifically described.

  First, the resin (A) will be described. The resin (A) has a weight average molecular weight Mw of 10,000 or more and 30,000 or less, preferably 12,000 to 28,000, and more preferably 14,000 to 26,000. In the present invention, by setting the mass average molecular weight of the resin (A) within the above range, it is considered that low-temperature fixability and good glossiness are imparted to the toner. That is, if the mass average molecular weight of the resin (A) is less than 10,000, it acts in a direction to reduce the viscosity and internal cohesive force of the binder resin, and the toner layer is easily broken at the time of fixing. Contamination into the image and the machine is likely to occur. If the mass average molecular weight is larger than 30,000, the viscosity of the binder resin and the internal cohesive force are increased, and the toner image cannot be fixed at a low temperature. Further, since the difference in molecular weight with the resin (B) is reduced, the compatibility tendency becomes strong, and it becomes impossible to give sufficient strength to the toner layer at the time of melting, and it is difficult to avoid breakage of the toner layer. It is also possible to become.

  The resin (A) has a softening point temperature Tsp (hereinafter referred to as a softening point temperature) of 80 ° C. or higher and 100 ° C. or lower, preferably 82 ° C. to 98 ° C., and more preferably 84 ° C. to 96 ° C. In the present invention, by setting the softening point temperature of the resin (A) within the above range, it is considered that the toner is imparted with low-temperature fixability and good toner storage property. That is, if the softening point temperature of the resin (A) is lower than 80 ° C., the toner is likely to melt even under a slightly higher temperature environment, so that it is difficult to keep the toner stably in a wide temperature range. There are concerns about the effect on heat-resistant storage. Also, if the softening point temperature of the resin (A) is higher than 100 ° C., the heat storage stability is improved, but the toner cannot be melted easily, and so-called low-temperature fixing that melts and fixes the toner image at a low temperature is realized. There is a concern that it will interfere.

  The resin (A) has a glass transition temperature Tg (hereinafter referred to as a glass transition temperature) of 30 ° C. or higher and 40 ° C. or lower, preferably 31 ° C. to 39 ° C., and more preferably 32 ° C. to 38 ° C. In the present invention, it is considered that by setting the glass transition temperature of the resin (A) within the above range, the toner is imparted with low-temperature fixability and good heat-resistant storage property. That is, when the glass transition temperature of the resin (A) is less than 30 ° C., the temperature range in which the resin (A) can be frozen is narrowed, and the temperature range causing molecular motion is expanded, so that the heat resistant storage stability of the toner is improved. There is a concern that it will cause trouble. On the other hand, if the glass transition temperature of the resin (A) exceeds 40 ° C., the temperature range in which the resin (A) can be frozen is expanded and contributes to the improvement of heat-resistant storage, but the micro Brownian motion cannot be started. It becomes difficult to melt and fix the toner image by setting the temperature lower.

  Thus, the presence of the resin (A) whose mass average molecular weight, softening point temperature, and glass transition temperature are set relatively low promotes smooth melting of the toner at the time of fixing. It is considered that the toner image can be formed. It is also conceivable that toner melting is promoted at a lower heating temperature than before.

  Next, the resin (B) has a mass average molecular weight of 250,000 or more and 350,000 or less, preferably 260,000 to 340,000, and more preferably 270,000 to 330,000. In the present invention, it is considered that strength is imparted to the toner according to the present invention by setting the mass average molecular weight of the resin (B) in the above range. That is, when the mass average molecular weight of the resin (B) is smaller than 250,000, the resin (B) hardly functions as a filler in the binder resin, and the strength cannot be imparted to the molten toner layer. It is thought that it is easy to break and hinders hot offset resistance. If the mass average molecular weight of the resin (B) is larger than 330,000, the resin (B) component cannot be completely melted within a predetermined time of the fixing step due to the high molecular weight, and a good gloss screen is obtained. There is a concern that it will not be possible.

  Resin (B) has a softening point temperature of 140 ° C. or higher and 160 ° C. or lower, preferably 142 ° C. to 158 ° C., more preferably 144 ° C. to 156 ° C. In the present invention, it is considered that the softening point temperature of the resin (B) is within the above range so as not to hinder the formation of a good glossy screen. That is, when the softening point temperature of the resin (B) is lower than 140 ° C., it is preferable for the formation of a uniform glossy surface by reliably melting at the time of fixing, but sufficient strength cannot be imparted to the molten toner layer and it is easy to break. Thus, the hot offset resistance is likely to be hindered. On the other hand, if the softening point temperature of the resin (B) is higher than 160 ° C., sufficient strength is given to the molten toner layer at the time of fixing, but if the fixing temperature is set low, it cannot be melted and gloss on the toner image. There is a concern that it will not be possible to grant.

  The resin (B) has a glass transition temperature of 60 ° C. or higher and 80 ° C. or lower, preferably 61 ° C. to 79 ° C., more preferably 62 ° C. to 78 ° C. In the present invention, it is considered that the toner according to the present invention is given good strength by setting the glass transition temperature of the resin (B) within the above range. That is, if the glass transition temperature of the resin (B) is lower than 60 ° C., the start temperature of the micro Brownian motion is lowered, which contributes to improving the adhesion of the toner image to the transfer sheet, but gives sufficient strength to the toner layer. The melted toner layer cannot be easily broken. Further, it is considered that the contaminated toner adhering to the transfer sheet surface or the fixing roller surface due to breakage is difficult to remove due to the low glass transition temperature.

  Thus, the presence of the resin (B) whose mass average molecular weight, softening point temperature, and glass transition temperature are set to be relatively high gives strength to the toner and avoids cutting of the molten toner layer during fixing. It seems to be. In particular, during continuous print production, where stress is frequently applied and frequently applied, it is considered that fracture of the melted toner layer is avoided by imparting strength with the resin (B), thereby contributing to improvement in hot offset resistance. .

  Next, the resin (C) has a mass average molecular weight of 5,000 or more and 20,000 or less, preferably 7,000 to 18,000, and more preferably 9,000 to 16,000. In the present invention, by setting the mass average molecular weight of the resin (C) within the above range, it is considered that the toner according to the present invention acts to promote strength improvement and glossy surface formation. That is, when the mass average molecular weight of the resin (C) is less than 5,000, it is difficult to improve the strength of the toner layer at the time of fixing because the viscosity of the resin (C) and the internal cohesive force are low. As a result, even if the resin (B) is contained, the molten toner layer is easily broken, and the image and the machine are easily contaminated by hot offset. On the other hand, if the mass average molecular weight is greater than 20,000, the viscosity and internal cohesive force of the resin (C) will increase, so that an appropriate strength is imparted to the molten toner layer during fixing, contributing to hot offset resistance. When the fixing temperature is set to a low value, the resin (C) is hardly melted and hinders glossiness on the toner image surface.

  Resin (C) has a softening point temperature of 100 ° C or higher and 120 ° C or lower, preferably 102 ° C to 118 ° C, and more preferably 104 ° C to 116 ° C. In the present invention, by setting the softening point temperature of the resin (C) within the above range, it is considered that the toner according to the present invention is provided with a good balance between heat-resistant storage property and low-temperature fixability. That is, if the softening point temperature of the resin (C) is lower than 100 ° C., there is a slight concern about the effect on heat-resistant storage stability. For example, the toner particles adhere to each other when left in a high temperature and high humidity environment for a long time. There is concern about the occurrence. Further, if the softening point temperature of the resin (C) is higher than 120 ° C., there is a concern that the toner melting does not proceed in the fixing step and it becomes difficult to smoothly melt and fix the toner image within a predetermined time. The

  Resin (C) has a glass transition temperature of 45 ° C or higher and 55 ° C or lower, preferably 46 ° C to 54 ° C, and more preferably 47 ° C to 53 ° C. In the present invention, by setting the glass transition temperature of the resin (C) within the above range, the environment in which the toner according to the present invention can be stored is expanded, and the ability to smoothly perform high-speed fixing during continuous printing is provided. It seems that there is. That is, when the glass transition temperature of the resin (C) is lower than 45 ° C., the temperature range in which the resin (C) can be frozen becomes narrow, so that the toner becomes soft in the storage environment and the toner particles adhere to each other. There is concern that it will be easier to do. Also, if the glass transition temperature of the resin (C) exceeds 55 ° C., the start temperature of the micro Brownian motion becomes high, so the melting of the toner image tends to be delayed at the initial stage of fixing, and in a short time like continuous printing. There is a concern that it may adversely affect image formation for fixing.

  Here, a method for measuring the mass average molecular weight, softening point temperature, and glass transition temperature of the resins (A), (B), and (C) constituting the toner according to the present invention will be described.

  The mass average molecular weights of the resins (A), (B), and (C) described above can be measured and calculated by a known molecular weight measurement method. Hereinafter, the procedure of the method for measuring the molecular weight of a resin by the GPC method (gel permeation chromatography), which is one of the typical methods for measuring the mass average molecular weight, will be described.

As a method for measuring the molecular weight of a resin by GPC (gel permeation chromatography), a measurement sample is dissolved in tetrahydrofuran so as to have a concentration of 1 mg / ml. As dissolution conditions, it is carried out at room temperature for 5 minutes using an ultrasonic disperser. Next, after processing with a membrane filter having a pore size of 0.2 μm, a 10 μL sample solution is injected into the GPC. Specific examples of GPC measurement conditions are shown below. That is,
Apparatus: HLC-8220 (manufactured by Tosoh Corporation)
Column: TSK guard column + TSK gel SuperHZM-M3 series (manufactured by Tosoh Corporation)
Column temperature: 40 ° C
Solvent: Tetrahydrofuran (THF)
Flow rate: 0.2 ml / min Detector: Refractive index detector (RI detector)
In the measurement of the molecular weight of the sample, the molecular weight distribution of the sample is calculated using a calibration curve measured using monodisperse polystyrene standard particles. Ten polystyrenes were used for calibration curve measurement.

  The softening point temperatures of the resins (A), (B), and (C) can be measured and calculated by a known measurement method. Hereinafter, the procedure of the softening point measurement by the flow tester method, which is one of the typical methods of softening point temperature measurement, will be described.

The softening point temperature is measured by the flow tester method according to the following procedure. That is,
(1) Sample preparation Temperature: 20 ± 1 ° C., relative humidity: 50 ± 5% RH, 1.1 g of toner is placed in a petri dish and left flat for 12 hours or more. -A (manufactured by Shimadzu Corporation) ”is pressed with a force of 3.75 × 10 ⁸ Pa (3820 kg / cm ² ) for 30 seconds to produce an in-mold sample having a diameter of 1 cm.

(2) Measurement of softening point The molded sample is set in “Flow Tester CFT-500D (manufactured by Shimadzu Corporation)” in an environment of temperature: 24 ± 5 ° C. and relative humidity: 50 ± 20% RH. Next, using a piston with a diameter of 1 cm from a hole (1 mm × 1 mm) of a cylindrical die under the conditions of a load of 196 N (20 kgf), a starting temperature of 60 ° C., a preheating time of 300 seconds, and a heating rate of 6 ° C./min. Extrude Extrusion is performed from the end of preheating. The offset method temperature Toffset measured at a setting of an offset value of 5 mm by the melting temperature measurement method of the temperature raising method was used as the softening point of the toner.

  Furthermore, the glass transition temperatures of the resins (A), (B), and (C) can be measured and calculated by a known glass transition temperature measurement method. Hereinafter, a procedure for measuring the glass transition temperature using a differential scanning calorimeter, which is one of the typical methods for measuring the glass transition temperature, will be described.

  The glass transition temperature can be measured using a DSC-7 differential scanning calorimeter (manufactured by PerkinElmer) and a TAC7 / DX thermal analyzer controller (manufactured by PerkinElmer).

  As a measurement procedure, 5.0 mg of toner is precisely weighed to two digits after the decimal point, sealed in an aluminum pan (KITNO.0219-0041), and set in a DSC-7 sample holder. The reference was an empty aluminum pan.

  As measurement conditions, the measurement temperature is 0 to 200 ° C., the temperature increase rate is 10 ° C./min, the temperature decrease rate is 10 ° C./min, and the heat-cool-heat control is performed, and the analysis is performed based on the data in the 2nd Heat. went.

  The glass transition temperature draws an extension of the baseline before the rise of the first endothermic peak and a tangent line indicating the maximum slope between the rise of the first peak and the peak apex, and the intersection is taken as the glass transition point. Show.

  Further, as a method for calculating the glass transition temperature, the following method for calculating the theoretical glass transition temperature can also be mentioned. Here, the theoretical glass transition temperature is calculated by multiplying the glass transition temperature when each component constituting the copolymer resin forms a homopolymer by the respective composition mass fraction, that is, by weighted averaging. is there.

  That is, the theoretical glass transition temperature Tg (referred to as absolute temperature Tg ′) is calculated from the following formula (1) using the glass transition temperature of the homopolymer of the component constituting the copolymer resin.

Formula (1): 1 / Tg ′ = W1 / T1 + W2 / T2 +... + Wn / Tn
(Wherein W1, W2,... Wn is the mass fraction of each polymerizable monomer with respect to the total polymerizable monomer constituting the copolymer resin, and T1, T2,... Tn are each polymerizable. (The glass transition temperature (absolute temperature) of a homopolymer formed using a monomer is shown.)
As described above, in the toner according to the present invention, the binder resin is composed of the resins (A), (B), and (C) described above, but the low-temperature fixability and the heat-resistant storage property are more reliably ensured. From the viewpoint of expression, it is preferable to have a core-shell structure. Specifically, a binder resin composed of a resin (A) and a resin (B), a core composed of a colorant and a wax, and a shell composed of a binder resin composed of a resin (C). Is preferred.

  That is, the resin (A) contributing to the low temperature fixability and the resin (B) added to improve the internal cohesive force of the resin (A) at the start of melting have good low temperature fixability as a core constituent resin. To express. Further, the heat-resistant storage property of the toner can be improved by forming the shell using the resin (C) having a glass transition temperature higher than that of the resin (A). As described above, by using the resins (A), (B), and (C) to obtain a function-separated structure type toner, the effects of the present invention can be expressed more reliably.

  Next, the polymerizable monomer capable of forming the resins (A), (B), and (C) will be described. The binder resin constituting the toner according to the present invention is formed using the resins (A), (B), and (C) having the above-described mass average molecular weight, softening point temperature, and glass transition temperature. Resin (A), (B), (C) can be formed using a well-known polymerizable monomer. Among these, a polymerizable monomer used to form a vinyl resin is preferable.

  Hereinafter, the polymerizable monomer used to form the vinyl resin will be described.

The resin according to the present invention contains a polymer obtained by polymerizing at least one polymerizable monomer as a constituent component. Examples of the polymerizable monomer include the following (1) to (10). Examples thereof include vinyl monomers. That is,
(1) Styrene or styrene derivatives Styrene, o-methylstyrene, m-methylstyrene, p-methylstyrene, α-methylstyrene, p-phenylstyrene, p-ethylstyrene, 2,4-dimethylstyrene, p-tert- Butyl styrene, pn-hexyl styrene, pn-octyl styrene, pn-nonyl styrene, pn-decyl styrene, pn-dodecyl styrene, etc. (2) Methacrylate derivatives Methyl methacrylate, methacryl Ethyl acetate, n-butyl methacrylate, isopropyl methacrylate, isobutyl methacrylate, t-butyl methacrylate, n-octyl methacrylate, 2-ethylhexyl methacrylate, stearyl methacrylate, lauryl methacrylate, phenyl methacrylate, diethyl methacrylate Aminoethyl, dimethylaminoethyl methacrylate, etc. (3) Acrylic acid ester derivatives Methyl acrylate, ethyl acrylate, isopropyl acrylate, n-butyl acrylate, t-butyl acrylate, isobutyl acrylate, n-octyl acrylate, 2-ethylhexyl acrylate, stearyl acrylate, lauryl acrylate, phenyl acrylate, and the like.

(4) Olefins Ethylene, propylene, isobutylene, etc. (5) Vinyl esters Vinyl propionate, vinyl acetate, vinyl benzoate, etc. (6) Vinyl ethers Vinyl methyl ether, vinyl ethyl ether, etc. (7) Vinyl ketones Vinyl methyl ketone, Vinyl ethyl ketone, vinyl hexyl ketone, etc. (8) N-vinyl compounds N-vinyl carbazole, N-vinyl indole, N-vinyl pyrrolidone, etc. (9) Vinyl compounds Vinyl naphthalene, vinyl pyridine, etc. (10) Acrylic acid or methacrylic acid Derivatives Acrylonitrile, methacrylonitrile, acrylamide, etc.

  Moreover, it is also possible to use combining the polymerizable monomer which has an ionic dissociation group as a polymerizable monomer which comprises resin. Examples of the ionic dissociation group include substituents such as a carboxyl group, a sulfonic acid group, and a phosphoric acid group, and the polymerizable monomer having an ionic dissociation group has these substituents.

Specific examples of the polymerizable monomer having an ionic dissociation group are given below. That is,
Acrylic acid, methacrylic acid, maleic acid, itaconic acid, cinnamic acid, fumaric acid, maleic acid monoalkyl ester, itaconic acid monoalkyl ester, styrene sulfonic acid, allyl sulfosuccinic acid, 2-acrylamido-2-methylpropane sulfonic acid, Acid phosphooxyethyl methacrylate, 3-chloro-2-acid phosphooxypropyl methacrylate, and the like.

Furthermore, it is also possible to use a polyfunctional vinyl as a polymerizable monomer constituting the resin to obtain a resin having a crosslinked structure. Specific examples of the polyfunctional vinyls are listed below. That is,
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, and the like.

  Next, materials other than the binder resin used when producing the toner according to the present invention, that is, a colorant, wax, and external additive will be described.

  As the colorant that can be used in the toner according to the present invention, known colorants can be used, and specific colorants are listed 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 can also be used.

  Examples of the colorant for magenta or red include C.I. I. Pigment Red 2, 3, 5, 6, 7, 15, 15, 48: 1, 53: 1, 57: 1, 60, 63, 64, 68, the same 81, 83, 87, 88, 89, 90, 112, 114, 122, 123, 139, 144, 149, 150, 163, 166, 170, 177, 178, 184, 202, 206, 207, 209, 222, 238, 269, and the like.

  Examples of the colorant for orange or yellow include C.I. I. Pigment Orange 31 and 43, C.I. I. Pigment Yellow 12, 14, 15, 17, 74, 83, 93, 94, 138, 155, 162, 180, 185, and the like.

  Further, as a colorant for green or cyan, C.I. I. Pigment Blue 2, 3, 15, 15, 15: 2, 15: 3, 15: 4, 16, 17, 17, 60, 62, 66, C.I. I. Pigment Green 7 etc.

  Examples of the dye include C.I. I. Solvent Red 1, 49, 52, 58, 63, 111, 122, C.I. I. Solvent Yellow 2, 6, 14, 15, 16, 19, 21, 21, 33, 44, 56, 61, 77, 79, 80, 81, 82, the same 93, 98, 103, 104, 112, 162, C.I. I. Solvent Blue 25, 36, 60, 70, 93, 95, etc.

  These colorants can be used alone or in combination of two or more as required. Further, the amount of the colorant added is in the range of 1 to 30% by mass, preferably 2 to 20% by mass, based on the whole toner, and a mixture thereof can also be used. The number average primary particle size varies depending on the type, but is preferably about 10 to 200 nm.

  As a method for adding the colorant, the resin fine particles are added at the stage of agglomeration by the addition of the flocculant to color the polymer. The colorant can also be used by treating the surface with a coupling agent or the like.

Next, the wax that can be used for the toner according to the present invention will be described. Examples of the wax that can be used in the toner according to the present invention include conventionally known waxes, and specific examples include the following. That is,
(1) Long-chain hydrocarbon wax Polyolefin wax such as polyethylene wax and polypropylene wax, paraffin wax, sazol wax, etc. (2) Ester wax Trimethylolpropane tribehenate, pentaerythritol tetramyristate, pentaerythritol tetrasteare Rate, pentaerythritol tetrabehenate, pentaerythritol diacetate dibehenate, glycerol tribehenate, 1,18-octadecanediol distearate, tristearyl trimellitic acid, distearyl maleate, etc. (3) Amide wax Ethylenediamine dibehenyl amide, trimellitic acid tristearyl amide, etc. (4) Dialkyl ketone waxes, distearyl ketone, etc. (5) Others Carnauba Vinegar, montan waxes, and the like.

  The melting point of the wax is usually 40 to 160 ° C, preferably 50 to 120 ° C, more preferably 60 to 90 ° C. By setting the melting point within the above range, the heat-resistant storage stability of the toner is ensured, and stable toner image formation can be performed even when fixing at a low temperature. Further, the wax content in the toner is preferably 1% by mass to 30% by mass, and more preferably 5% by mass to 20% by mass.

  Next, a toner manufacturing method according to the present invention will be described.

  The toner according to the present invention contains at least a resin (A) having a mass average molecular weight of 10,000 to 30,000, a softening point of 80 ° C. to 100 ° C., and a glass transition temperature of 30 ° C. to 40 ° C. Aggregating resin particles and resin particles containing resin (B) having a weight average molecular weight of 250,000 to 350,000, a softening point of 140 ° C. to 160 ° C., and a glass transition temperature of 60 ° C. to 80 ° C. Then, the resin particles containing the resin (C) having a mass average molecular weight of 5,000 to 20,000, a softening point of 100 ° C. to 120 ° C., and a glass transition temperature of 45 ° C. to 55 ° C. are aggregated. It is produced through a process.

  As a typical method for producing a toner through the above steps, for example, a so-called emulsion association method for producing a toner through the following steps can be mentioned. The following process includes a process for producing a toner having a core-shell structure. However, when a toner having a structure other than the core-shell structure is to be produced, the same procedure is used except that the processes (5) and (6) are eliminated. Can do.

(1) Dissolution / dispersion step for dissolving or dispersing a release agent in a radical polymerizable monomer (2) Polymerization step for preparing a dispersion of resin fine particles (3) Resin fine particles and colorant particles in an aqueous medium Agglomeration and fusion step for aggregating and fusing the particles to obtain associated particles (core particles) (4) a first aging step for adjusting the shape by aging the associated particles with thermal energy (5) in the core particle dispersion Shell forming step of adding shell resin particles to agglomerate and fuse the shell particles on the surface of the core particles to form core-shell structured colored particles (6) Aging the core-shell structured colored particles with thermal energy Second aging step for adjusting the shape of the core-shell structured colored particles (7) The washing step for solid-liquid separation of the colored particles from the cooled colored particle dispersion and removing the surfactant from the colored particles (8) ) Washed A drying step of drying the colored particles. If necessary, after the drying step,
(9) There may be a step of adding an external additive to the dried colored particles. The above steps will be described in detail later.

  In the present invention, the resin particles containing the resin (A) and the resin particles containing the resin (B) are first aggregated to form a core first, and then the resin (C) described above is formed on the core surface. It is also possible to produce a core-shell toner by aggregating the resin particles contained therein to form a shell. Thus, in the present invention, first, resin particles (A) and (B) and colorant particles are associated and fused to produce core particles (hereinafter referred to as core particles), followed by core particle dispersion. A toner having a core-shell structure is prepared by adding resin particles (C) to the liquid, aggregating and fusing the resin particles (C) on the surface of the core particles, and coating the surface of the core particles with the resin particles (C). Can do.

  When a toner having a core-shell structure is prepared, it is preferable that the toner has an extremely thin shell and a constant film thickness. A uniform toner can be produced more reliably. In order to produce a toner having a uniform shape and particle size, core particles having a uniform particle size and shape are prepared, and a shell resin particle is added thereto to form a shell. Is preferred.

  The shelling step is a step of controlling the final toner shape and particle size, but the resin particles for the shell are added under the same conditions to each core particle. It is preferable that the diameter and shape are uniform. If the core particles have the same particle size and shape, the toner particles having the same shape and size are formed while the shell-forming resin particles are easily uniformly adhered to the surface, and a shell having a uniform thickness is formed. Particles can be produced reliably.

  The core particles constituting the toner according to the present invention are produced by a production method in which resin fine particles and colorant particles are aggregated and fused. The shape of the core particles is controlled, for example, by controlling the heating temperature in the aggregation / fusion process and the heating temperature and time in the first aging process.

  Of these, the time control in the first aging step is the most effective. Since the ripening step is intended to adjust the circularity of the associated particles, the target circularity is reached by controlling this time.

  The core part constituting the toner according to the present invention is, for example, after dissolving or dispersing the release agent component in the polymerizable monomer forming the resin (A), and then mechanically dispersing fine particles in the aqueous medium. A method of salting out and fusing the composite resin fine particles formed through the step of polymerizing the polymerizable monomer by the miniemulsion polymerization method and the colorant particles, which will be described later, is preferably used. The method of dissolving the release agent component in the polymerizable monomer may be either a method of dissolving or melting the release agent component.

  Hereinafter, each manufacturing process of the toner by the emulsion association method will be described.

(1) Dissolution / dispersion step This step is a step of preparing a radical polymerizable monomer solution in which the release agent compound is dissolved in the radical polymerizable monomer and the release agent compound is mixed.

(2) Polymerization step In a preferred example of this polymerization step, a radical polymerizable monomer solution in which a wax is dissolved or dispersed in an aqueous medium containing a surfactant having a critical micelle concentration (CMC) or less is added. Then, mechanical energy is applied to form droplets, and then a water-soluble radical polymerization initiator is added to advance the polymerization reaction in the droplets. Note that an oil-soluble polymerization initiator may be contained in the droplet. In such a polymerization process, mechanical energy is imparted and forcedly emulsified (formation of droplets) is essential. Examples of the means for applying mechanical energy include means for applying strong stirring or ultrasonic vibration energy such as homomixer, ultrasonic wave, and manton gorin.

  By this polymerization step, resin fine particles containing a wax and a binder resin are obtained. Such resin fine particles may be either colored fine particles or fine particles that are not colored. The colored resin fine particles can be produced by polymerizing a monomer composition containing a colorant. In addition, when a toner is prepared using resin particles that are not colored, a dispersion of colorant particles is added to a dispersion of resin particles in the aggregation / fusion process described below to obtain resin particles and colorant particles. By fusing, toner base particles called colored particles can be produced.

(3) Aggregation / fusion process In this aggregation / fusion process, as a specific method for agglomerating and fusing the resin fine particles (colored or non-colored resin fine particles) obtained by the polymerization process, salting out / fusion is possible. The method is preferred. In the agglomeration / fusion step, it is possible to agglomerate and fuse internal additive fine particles such as release agent fine particles and charge control agents together with resin fine particles and colorant fine particles.

  Here, “salting out / fusion” means that the aggregation and fusion of resin fine particles and the like proceed in parallel, and when the particles grow to a desired particle size, an aggregation terminator is added to stop the particle growth. In order to control the particle shape as needed, heating is continued.

  Further, the “aqueous medium” in the aggregation / fusion process refers to a material in which the main component (50% by mass or more) is made of water. Examples of components other than water include organic solvents that dissolve in water, such as methanol, ethanol, isopropanol, butanol, acetone, methyl ethyl ketone, and tetrahydrofuran.

  The colorant fine particles can be prepared by dispersing the colorant in an aqueous medium. The dispersion treatment of the colorant is performed in a state where the surfactant concentration is set to a critical micelle concentration (CMC) or more in water. The disperser used for the dispersion treatment of the colorant is not particularly limited, but preferably an ultrasonic disperser, a mechanical homogenizer, a pressure disperser such as a manton gorin or a pressure homogenizer, a sand grinder, a Getzmann mill, a diamond fine mill, or the like. Examples thereof include a medium type disperser.

  Examples of the surfactant used in the aqueous medium include the same surfactants as those described above. The colorant (fine particles) may be a surface modified one. In the surface modification method of the colorant, the colorant is dispersed in a solvent, the surface modifier is added to the dispersion, and the system is reacted by raising the temperature. After completion of the reaction, the colorant is separated by filtration, washed and filtered with the same solvent, and dried to obtain a colorant (pigment) treated with the surface modifier.

  The salting out / fusing method, which is a preferred agglomeration and fusing method, is a salting out method comprising an alkali metal salt, an alkaline earth metal salt, a trivalent salt, or the like in water in which resin fine particles and colorant fine particles are present. Add the agent as a coagulant with a critical coagulation concentration or higher, and then proceed to salting out by heating to a temperature above the glass transition point of the resin fine particles and above the melting peak temperature (° C) of the mixture. At the same time, it is a step of performing fusion. Here, the alkali metal salt and the alkaline earth metal salt which are salting-out agents include lithium, potassium, sodium and the like as the alkali metal, and examples of the alkaline earth metal include magnesium, calcium, strontium and barium. Preferably, potassium, sodium, magnesium, calcium, and barium are used.

  When agglomeration and fusion are performed by salting out / fusion, it is preferable to make the time allowed to stand after adding the salting-out agent as short as possible. The reason for this is that depending on the standing time after salting out, the aggregation state of the particles may fluctuate and the particle size distribution may become unstable, or the surface properties of the fused particles may vary. This is because of concern. Moreover, it is preferable that the addition temperature of the salting-out agent is at least equal to or lower than the glass transition temperature of the resin fine particles. This is because if the addition temperature of the salting-out agent is equal to or higher than the glass transition temperature of the resin fine particles, salting out / fusion of the resin fine particles proceeds rapidly, but it becomes difficult to control the particle size. This is because there are concerns about the occurrence of problems such as generation of particles having a particle size. A preferable range of the addition temperature of the salting-out agent is not higher than the glass transition temperature of the resin, but is generally 5 to 55 ° C, preferably 10 to 45 ° C.

  In addition, after adding the salting-out agent below the glass transition temperature of the resin fine particles, the temperature is raised as quickly as possible, and heated to a temperature equal to or higher than the glass transition temperature of the resin fine particles and higher than the melting peak temperature of the mixture. It is preferable to do. The time until this temperature rise is preferably less than 1 hour. Further, although it is necessary to quickly raise the temperature, the rate of temperature rise is preferably 0.25 ° C./min or more. The upper limit of the rate of temperature rise is not particularly specified, but if the temperature is raised rapidly, salting out proceeds rapidly, which may cause a problem that it is difficult to control the particle size. The following is preferred.

  By this aggregation / fusion process, a dispersion liquid of associated particles (core particles) formed by salting out / fusion of resin fine particles and arbitrary fine particles is obtained.

(4) First ripening step Next, by controlling the heating temperature in the aggregation / fusion step and particularly the heating temperature and time in the first ripening step, the surface of the core particles formed with a uniform particle size and a narrow distribution is obtained. Control to have a smooth but uniform shape. Specifically, the heating temperature is lowered in the aggregation / fusion process to suppress the progress of fusion between the resin particles to promote homogenization, the heating temperature is lowered in the first aging process, and the time The surface of the core particles is controlled to have a uniform shape by increasing the length.

(5) Shelling step In the shelling step, the resin particle dispersion for the shell is added to the core particle dispersion to agglomerate and fuse the resin particles for the shell onto the surface of the core particles. The resin particles are coated to form colored particles serving as a base of toner particles.

  Specifically, the core particle dispersion is added with a dispersion of resin particles for shells while maintaining the temperature in the above-described aggregation / fusion process and the first aging process, and it takes several hours while continuing heating and stirring. Then, the resin particles for shell are slowly coated on the surface of the core particles to form colored particles. The heating and stirring time is preferably 1 hour to 7 hours, particularly preferably 3 hours to 5 hours.

(6) Second ripening step Resin for shell which is added to a core particle after adding a terminator such as sodium chloride to stop the particle growth at the stage when colored particles become a predetermined particle size by shelling. Heating and stirring are continued for several hours in order to fuse the particles. In the shelling step, a shell having a thickness of 100 to 300 nm is formed on the surface of the core particle. In this way, resin particles are fixed to the surface of the core particles to form a shell, and rounded and colored particles having a uniform shape are formed.

  In the present invention, it is possible to control the shape of the colored particles in the true sphere direction by setting the time of the second aging step longer or by setting the aging temperature higher.

(7) Washing step In this step, first, the dispersion liquid of the colored particles is subjected to a cooling process (rapid cooling process). As cooling process conditions, it can cool at the cooling rate of 1-20 degreeC / min, for example. The cooling treatment method is not particularly limited, and examples include known methods such as a method of cooling by introducing a refrigerant from the outside of the reaction vessel, and a method of cooling by directly introducing cold water into the reaction system. it can.

  Next, the cooled colored particle dispersion is subjected to solid-liquid separation, and the solid-liquid separated colored particles are washed. That is, a colored liquid toner cake (in a wet state) formed by performing solid-liquid separation processing for solid-liquid separation of the colored particles from the colored particle dispersion liquid that has been cooled to a predetermined temperature by performing a cooling process. Deposits such as surfactants and salting-out agents are removed from the aggregate of colored particles agglomerated in a cake. A typical example of the solid-liquid separation process is a filtration process. As a specific method of the filtration process, for example, a centrifugal separation method, a vacuum filtration method using Nutsche or the like, a filter press, or the like is used. There are filtration methods.

(8) Drying step This step is a step of drying the washed cake to obtain dried colored particles. Examples of dryers that can be used in this process include known drying processors such as spray dryers, vacuum freeze dryers, and vacuum dryers, stationary shelf dryers, mobile shelf dryers, fluidized bed dryers, It is also possible to use a rotary dryer, a stirring dryer or the like. The water content of the dried colored particles is preferably 5% by mass or less, and more preferably 2% by mass or less.

  In addition, when the dried colored particles are aggregated with weak interparticle attractive force, the aggregate can be crushed. Specific examples of the crushing treatment apparatus include mechanical crushing treatment apparatuses such as a jet mill, a Henschel mixer, a coffee mill, and a food processor.

(9) External Addition Processing Step This step is a step of preparing a toner by adding and mixing external additives as necessary to the dried colored particles.

  The colored particles produced through the above steps can be used as toner particles as they are. However, from the viewpoint of improving charging performance, fluidity, or cleaning properties, the surface of the colored particles is made of known inorganic fine particles or organic fine particles. It is preferable to add the particles as an external additive.

  The type of the external additive is not particularly limited, and examples thereof include the following inorganic fine particles, organic fine particles, and lubricants.

  As the inorganic fine particles, conventionally known fine particles can be used. For example, silica, titania, alumina, strontium titanate fine particles and the like are preferable.

  Moreover, what hydrophobized these inorganic fine particles as needed can also be used.

  Specific examples of the silica fine particles include commercially available products R-805, R-976, R-974, R-972, R-812, R-809 manufactured by Nippon Aerosil Co., Ltd., HVK-2150 manufactured by Hoechst, H -200, commercially available products TS-720, TS-530, TS-610, H-5, MS-5 and the like manufactured by Cabot Corporation.

  As the titania fine particles, for example, commercially available products T-805 and T-604 manufactured by Nippon Aerosil Co., Ltd., commercially available products MT-100S, MT-100B, MT-500BS, MT-600, MT-600SS, JA- 1. Commercial products TA-300SI, TA-500, TAF-130, TAF-510, TAF-510T manufactured by Fuji Titanium Co., Ltd. Commercial products IT-S, IT-OA, IT-OB, IT- manufactured by Idemitsu Kosan Co., Ltd. OC etc. are mentioned.

  Examples of the alumina fine particles include commercial products RFY-C and C-604 manufactured by Nippon Aerosil Co., Ltd. and commercial products TTO-55 manufactured by Ishihara Sangyo Co., Ltd.

  As the organic fine particles, spherical organic fine particles having a number average primary particle diameter of about 10 to 2000 nm can be used. Specifically, homopolymers such as styrene and methyl methacrylate and copolymers thereof can be used.

  Further, a lubricant can be used to further improve the cleaning property and transfer property, and examples thereof include the following higher fatty acid metal salts. That is, salts of zinc stearate, aluminum, copper, magnesium, calcium, etc., zinc oleate, salts of manganese, iron, copper, magnesium, etc., zinc palmitate, salts of copper, magnesium, calcium, etc., linoleic acid And salts of zinc and calcium of ricinoleic acid.

  The addition amount of these external additives and lubricants is preferably 0.1 to 10.0% by mass with respect to the whole toner. Examples of methods for adding external additives and lubricants include methods using various known mixing devices such as a turbuler mixer, a Henschel mixer, a nauter mixer, and a V-type mixer.

  Next, a polymerization initiator, a dispersion stabilizer, a surfactant and the like used when the toner according to the present invention is produced in an aqueous medium will be described.

When the binder resin constituting the toner according to the present invention is formed using a vinyl polymerizable monomer, a known oil-soluble or water-soluble polymerization initiator can be used. Specific examples of the oil-soluble polymerization initiator include the following azo or diazo polymerization initiators and peroxide polymerization initiators. That is,
(1) Azo or diazo polymerization initiator 2,2'-azobis- (2,4-dimethylvaleronitrile), 2,2'-azobisisobutyronitrile, 1,1'-azobis (cyclohexane-1 -Carbonitrile), 2,2'-azobis-4-methoxy-2,4-dimethylvaleronitrile, azobisisobutyronitrile, etc. (2) peroxide-based polymerization initiators benzoyl peroxide, methyl ethyl ketone peroxide, diisopropyl Peroxycarbonate, cumene hydroperoxide, t-butyl hydroperoxide, di-t-butyl peroxide, dicumyl peroxide, 2,4-dichlorobenzoyl peroxide, lauroyl peroxide, 2,2-bis- (4 4-t-butylperoxycyclohexyl) propane, tris (T-butylperoxy) triazine In the case of forming the resin particles by emulsion polymerization is a water-soluble radical polymerization initiators can be used. 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.

  In addition, a known chain transfer agent can be used for adjusting the molecular weight of the resin particles. Specific examples include octyl mercaptan, dodecyl mercaptan, tert-dodecyl mercaptan, n-octyl-3-mercaptopropionic acid ester, terpinolene, carbon tetrabromide, α-methylstyrene dimer and the like.

  In the present invention, a method is preferably employed in which the polymerization is carried out in a state where the polymerizable monomer is dispersed in the aqueous medium, or the toner particles are produced by agglomerating and fusing the resin particles dispersed in the aqueous medium. In order to stably disperse these in an aqueous medium, it is preferable to use a dispersion stabilizer.

  Examples of the dispersion stabilizer include tricalcium phosphate, magnesium phosphate, zinc phosphate, aluminum phosphate, calcium carbonate, magnesium carbonate, calcium hydroxide, magnesium hydroxide, aluminum hydroxide, calcium metasilicate, calcium sulfate, Examples include barium sulfate, bentonite, silica, and alumina. In addition, polyvinyl alcohol, gelatin, methylcellulose, sodium dodecylbenzenesulfonate, ethylene oxide adduct, higher alcohol sodium sulfate and the like that can be generally used as a surfactant can be used as a dispersion stabilizer.

  Further, when polymerization is performed using a polymerizable monomer in an aqueous medium, it is necessary to uniformly disperse oil droplets of the polymerizable monomer in the aqueous medium using a surfactant. In this case, usable surfactants are not particularly limited, but for example, the following ionic surfactants can be used as preferable ones. Examples of the ionic surfactant include a sulfonate, a sulfate ester salt, and a fatty acid salt. Examples of the sulfonate include sodium dodecylbenzenesulfonate, sodium arylalkylpolyethersulfonate, and 3,3-disulfonediphenyl. Urea-4,4-diazo-bis-amino-8-naphthol-6-sulfonate sodium, ortho-carboxybenzene-azo-dimethylaniline, 2,2,5,5-tetramethyl-triphenylmethane-4,4 -Sodium diazo-bis-β-naphthol-6-sulfonate.

  Examples of sulfate salts include sodium dodecyl sulfate, sodium tetradecyl sulfate, sodium pentadecyl sulfate, and sodium octyl sulfate. Fatty acid salts include sodium oleate, sodium laurate, sodium caprate, sodium caprylate, Examples include sodium caproate, potassium stearate, and calcium oleate.

  Nonionic surfactants can also be used. Specifically, polyethylene oxide, polypropylene oxide, a combination of polypropylene oxide and polyethylene oxide, esters of polyethylene glycol and higher fatty acids, alkylphenol polyethylene oxide, higher fatty acids and Examples include polyethylene glycol esters, higher fatty acid and polypropylene oxide esters, sorbitan esters, and the like.

  Next, a developer using the toner according to the present invention will be described.

  The toner according to the present invention can be used for both a one-component developer (including magnetic and non-magnetic) that forms an image without using a carrier and a two-component developer that forms an image using a carrier. is there.

  When used as a two-component developer, it can be prepared by mixing toner and carrier. The mixing amount of the toner with respect to the carrier is preferably 2 to 10% by mass. The mixing apparatus for mixing the toner and the carrier is not particularly limited, and examples thereof include a Nauter mixer, a W cone, and a V-type mixer.

  The carrier is preferably a ferrite carrier having a volume average particle size of 10 to 60 μm and a saturation magnetization value of 20 to 80 emu / g. Thus, by using a carrier having a small carrier particle size and a low saturation magnetization value, the magnetic brush on the developing sleeve becomes soft, and an electrophotographic image with good sharpness can be formed.

  The volume average particle diameter can be measured by, for example, a laser diffraction particle size analyzer “HELOS (manufactured by Sympatec Corporation)” equipped with a wet disperser. The saturation magnetization can be measured by, for example, “DC magnetization characteristic automatic recording device 3257-35 (manufactured by Yokogawa Electric Corporation)”.

  It is preferable that the carrier has magnetic particles as a core (core) and the surface thereof is coated with a resin. The resin used for coating the carrier core material is not particularly limited, and various resins can be used. For the positively chargeable toner, for example, a fluorine resin, a fluorine-acrylic resin, a silicone resin, a modified silicone resin, or the like can be used, and a condensation type silicone resin is preferable. For negatively chargeable toners, for example, acrylic-styrene resins, mixed resins of acrylic-styrene resins and melamine resins and cured resins thereof, silicone resins, modified silicone resins, epoxy resins, polyesters Resin, urethane resin, polyethylene resin, etc. can be used. Among these, a mixed resin of an acrylic-styrene resin and a melamine resin, a cured resin thereof, and a condensation type silicone resin are preferable. If necessary, a two-component developer can be formed by adding a charge control agent, an adhesion improver, a primer treatment agent, a resistance control agent, and the like.

  When the toner is used as a non-magnetic one-component developer that forms an image without using a carrier, the toner is rubbed against and pressed against the charging member and the developing roller surface during image formation. Image formation by the non-magnetic one-component development method can simplify the structure of the developing device, and thus has an advantage that the entire image forming device can be made compact. Therefore, when the toner according to the present invention is used as a non-magnetic one-component developer, a full color print can be created with a compact color printer, and a full color print excellent in color reproducibility can be created even in a space-limited work environment. Is possible.

  A magnetic toner which is one of the one-component developers can be produced by using magnetic fine particles as a colorant. As the magnetic fine particles, particles such as ferrite and magnetite having an average primary particle diameter of 0.1 to 2.0 μm are used. The addition amount of the magnetic fine particles is preferably 20 to 70% by mass in the toner.

  Further, from the viewpoint of imparting fluidity, it is possible to mix known inorganic fine particles. As the inorganic fine particles, inorganic oxide particles such as silica, titania and alumina are preferable, and these inorganic fine particles are more preferably hydrophobized with a silane coupling agent or a titanium coupling agent.

  Next, an image forming apparatus capable of forming an image using the toner according to the present invention will be described. FIG. 1 is a schematic view showing an example of an image forming apparatus that can be used when the toner according to the present invention is used as a two-component developer.

  In FIG. 1, 1Y, 1M, 1C and 1K are photoreceptors, 4Y, 4M, 4C and 4K are developing devices, 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 devices, 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 above 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, as one of the other different color toner images, the image forming unit 10K that forms a black image includes a drum-shaped photoconductor 1K as a first photoconductor, and a charge disposed around the photoconductor 1K. Means 2K, exposure means 3K, developing means 4K, primary transfer roll 5K as primary transfer means, and 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 by the cleaning unit 6A from the endless belt-shaped intermediate transfer body 70 in which the recording member P is separated by curvature.

  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 comes into pressure contact with the endless belt-shaped intermediate transfer body 70 only when the recording member P passes through the secondary transfer roll 5A and secondary transfer is performed.

  In this manner, 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 the recording member P is collectively collected. Then, the image is fixed and fixed by pressure and heating by the fixing device 24. 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 charging, exposure, and development cycle. The next image formation is performed.

  As an image forming method when the toner according to the present invention is used as a non-magnetic one-component developer, the two-component developing device may be replaced with a non-magnetic one-component developing device.

  FIG. 1 shows a roller fixing type fixing device including a heating roller and a pressure roller. However, the fixing method is not particularly limited, and the above-described roller fixing method, heating roller, and heating roller are not limited. Known fixing methods such as a fixing method comprising a pressure belt, a fixing method comprising a heating belt and a pressure roller, and a belt fixing method comprising a heating belt and a pressure belt can be used. As the heating method, any known heating method such as a halogen lamp method or an IH fixing method can be employed.

  The recording paper on which an image can be formed using the toner according to the present invention is generally called a transfer material or an image support. For example, toner formed by a known image forming method using the above-described image forming apparatus or the like. There is no particular limitation as long as it holds an image. Examples of the recording paper that can be used in the present invention include known paper such as plain paper from thin paper to thick paper, high-quality paper, art paper, coated printing paper such as coated paper, and commercially available Japanese paper. There are postcard paper, plastic films for OHP, cloth, and the like.

  EXAMPLES The present invention will be described below with reference to examples, but the present invention is not limited to these embodiments.

1. Production of “Toners 1 to 15” “Toners 1 to 15” were produced through the steps of aggregating and fusing three kinds of resin fine particles by the following procedure. That is,
1-1. Preparation of “resin fine particle dispersions A1 to A5” (1) Preparation of “resin fine particle dispersion A1” (a) First-stage polymerization An anion was placed in a reaction vessel equipped with a stirrer, a temperature sensor, a cooling tube, and a nitrogen introduction device. A surfactant solution in which 2.0 parts by mass of a surfactant (sodium dodecylbenzenesulfonate: SDS) was dissolved in 2900 parts by mass of ion-exchanged water was added, and the mixture was stirred while stirring at a rate of 230 rpm under a nitrogen stream. The temperature was raised to 80 ° C.

After adding 9.0 parts by mass of a polymerization initiator (potassium persulfate: KPS) to the surfactant solution and adjusting the internal temperature to 78 ° C,
Styrene 551 parts by mass n-butyl acrylate 280 parts by mass Methacrylic acid 44 parts by mass n-Octyl mercaptan 14.6 parts by mass A monomer mixed solution [1] was added dropwise over 3 hours.

  After completion of the dropwise addition, the polymerization reaction was carried out by heating and stirring at 78 ° C. for 1 hour to prepare a dispersion of resin fine particles. This resin fine particle dispersion is referred to as “resin fine particle dispersion a1”.

(B) Second-stage polymerization: formation of an intermediate layer A monomer mixed solution composed of the following compounds was put into a flask equipped with a stirrer, followed by paraffin wax “HNP-57 (Nippon Seiwa) as a release agent. 51 parts by mass) was added and dissolved by heating to 85 ° C. In this way, a monomer mixed solution [2] was prepared.

Styrene 104 parts by weight n-butyl acrylate 53 parts by weight Methacrylic acid 8 parts by weight n-octyl mercaptan 2.7 parts by weight On the other hand, 2 parts by weight of an anionic surfactant (polyoxy (2) dodecyl ether sulfate sodium salt) is ion-exchanged. A surfactant solution dissolved in 1100 parts by mass of water was prepared and heated to 90 ° C. To this surfactant solution, 28 parts by mass (in terms of solid content) of the above-mentioned “resin fine particle dispersion a1” was added, and after adding the monomer mixed solution [2], a mechanical disperser having a circulation path “ "Clea mix (M Technique Co., Ltd.)" was mixed and dispersed for 4 hours. An emulsified particle dispersion containing emulsified particles having a dispersed particle size of 350 nm was prepared by the mixing and dispersing.

  Next, a polymerization initiator solution in which 2.5 parts by mass of a polymerization initiator (KPS) is dissolved in 110 parts by mass of ion-exchanged water is added to the emulsified particle dispersion, and the system is heated at 90 ° C. for 2 hours. A polymerization reaction (second stage polymerization) was performed by stirring to prepare a dispersion of resin fine particles. This resin particle dispersion is designated as “resin particle dispersion a11”.

(C) Third-stage polymerization: Formation of outer layer In “resin fine particle dispersion a11” obtained by the second-stage polymerization, 2.5 parts by mass of a polymerization initiator (KPS) was dissolved in 110 parts by mass of ion-exchanged water. An aqueous polymerization initiator solution was added, and a monomer mixed solution [3] comprising the following compound was added dropwise over 1 hour under a temperature condition of 80 ° C.

Styrene 231 parts by mass n-butyl acrylate 99 parts by mass n-octyl mercaptan 4.4 parts by mass After completion of dropping, the mixture was heated and stirred for 3 hours to conduct a polymerization reaction (third stage polymerization). A “resin fine particle dispersion A1” composed of composite resin fine particles having a multilayer structure was produced by cooling to 0 ° C. The “resin fine particles A1” constituting the “resin fine particle dispersion A1” had a weight average molecular weight of 20,000, a softening point of 90 ° C., and a glass transition temperature of 35 ° C.

(2) Production of “resin fine particle dispersions A2 to A5” (a) Production of “resin fine particle dispersion A2” Monomer mixed solution used in the first stage polymerization in the production of “resin fine particle dispersion A1” The addition amount of each compound constituting [1] was changed as follows. That is,
Styrene 529 parts by weight n-butyl acrylate 303 parts by weight Methacrylic acid 44 parts by weight n-octyl mercaptan 17.4 parts by weight The addition amount of each compound constituting the monomer mixed solution [2] used in the second stage polymerization Was changed as follows. That is,
Styrene 100 parts by mass n-butyl acrylate 57 parts by mass Methacrylic acid 8 parts by mass n-octyl mercaptan 3.3 parts by mass Furthermore, the addition amount of each compound constituting the monomer mixed solution [3] used in the third stage polymerization Was changed as follows. That is,
Styrene 222 parts by mass n-butyl acrylate 108 parts by mass n-octyl mercaptan 6.5 parts by mass The same procedure except that the addition amount of each compound constituting each monomer mixed solution was changed as described above. Liquid A2 "was prepared. The “resin fine particles A2” constituting the “resin fine particle dispersion A2” had a weight average molecular weight of 10,000, a softening point of 80 ° C., and a glass transition temperature of 30 ° C.

(B) Production of “resin fine particle dispersion A3” In the production of “resin fine particle dispersion A1”, the addition amount of each compound constituting the monomer mixed solution [1] used in the first stage polymerization was as follows. Changed. That is,
Styrene 578 parts by mass n-butyl acrylate 254 parts by mass Methacrylic acid 44 parts by mass n-octyl mercaptan 11.8 parts by mass The addition amount of each compound constituting the monomer mixed solution [2] used in the second stage polymerization Was changed as follows. That is,
Styrene 109 parts by weight n-butyl acrylate 48 parts by weight Methacrylic acid 8 parts by weight n-octyl mercaptan 2.2 parts by weight Further, the amount of each compound constituting the monomer mixed solution [3] used in the third stage polymerization Was changed as follows. That is,
Styrene 240 parts by mass n-butyl acrylate 90 parts by mass n-octyl mercaptan 4.4 parts by mass The same procedure except that the addition amount of each compound constituting each monomer mixed solution was changed as described above. Liquid A3 "was prepared. The “resin fine particles A3” constituting the “resin fine particle dispersion A3” had a weight average molecular weight of 30,000, a softening point of 100 ° C., and a glass transition temperature of 40 ° C.

(C) Production of “resin fine particle dispersion A4” In the production of “resin fine particle dispersion A1”, the addition amount of each compound constituting the monomer mixed solution [1] used in the first stage polymerization was as follows. Changed. That is,
Styrene 503 parts by weight n-butyl acrylate 328 parts by weight Methacrylic acid 44 parts by weight n-octyl mercaptan 23.1 parts by weight The addition amount of each compound constituting the monomer mixed solution [2] used in the second stage polymerization Was changed as follows. That is,
Styrene 95 parts by mass n-butyl acrylate 62 parts by mass Methacrylic acid 8 parts by mass n-octyl mercaptan 4.4 parts by mass Furthermore, the addition amount of each compound constituting the monomer mixed solution [3] used in the third stage polymerization Was changed as follows. That is,
Styrene 212 parts by weight n-butyl acrylate 118 parts by weight n-octyl mercaptan 8.7 parts by weight The same procedure was followed except that the addition amount of each compound constituting each monomer mixed solution was changed as described above. Liquid A4 "was prepared. The “resin fine particles A4” constituting the “resin fine particle dispersion A4” had a weight average molecular weight of 8,000, a softening point of 75 ° C., and a glass transition temperature of 25 ° C.

(D) Production of “resin fine particle dispersion A5” In the production of “resin fine particle dispersion A1”, the addition amount of each compound constituting the monomer mixed solution [1] used in the first stage polymerization was as follows. Changed. That is,
Styrene 600 parts by weight n-butyl acrylate 231 parts by weight Methacrylic acid 44 parts by weight n-octyl mercaptan 8.8 parts by weight The addition amount of each compound constituting the monomer mixed solution [2] used in the second stage polymerization Was changed as follows. That is,
Styrene 113 parts by mass n-butyl acrylate 44 parts by mass Methacrylic acid 8 parts by mass n-octyl mercaptan 1.7 parts by mass Furthermore, the addition amount of each compound constituting the monomer mixed solution [3] used in the third stage polymerization Was changed as follows. That is,
Styrene 249 parts by mass n-butyl acrylate 81 parts by mass n-octyl mercaptan 3.3 parts by mass The same procedure except that the addition amount of each compound constituting each monomer mixed solution was changed as described above. Liquid A5 "was prepared. The “resin fine particles A5” constituting the “resin fine particle dispersion A5” had a weight average molecular weight of 35,000, a softening point of 105 ° C., and a glass transition temperature of 45 ° C.

1-2. Preparation of “resin fine particle dispersions B1 to B5” (1) Preparation of “resin fine particle dispersion B1” An anionic surfactant (dodecylbenzene) was placed in a reaction vessel equipped with a stirrer, temperature sensor, cooling pipe, and nitrogen introducing device. A surfactant solution in which 2.0 parts by mass of sodium sulfonate (SDS) was dissolved in 2900 parts by mass of ion-exchanged water was added, and the internal temperature was raised to 80 ° C. while stirring at a stirring speed of 230 rpm under a nitrogen stream. I let you.

After adding 9.0 parts by mass of a polymerization initiator (potassium persulfate: KPS) to the surfactant solution and adjusting the internal temperature to 78 ° C,
Styrene 648 parts by weight n-butyl acrylate 153 parts by weight Methacrylic acid 74 parts by weight n-octyl mercaptan 0.15 parts by weight A monomer mixed solution [4] was added dropwise over 3 hours.

  After completion of the dropwise addition, the polymerization reaction was carried out by heating and stirring at 78 ° C. for 1 hour to prepare a dispersion of resin fine particles. This resin fine particle dispersion is referred to as “resin fine particle dispersion B1”. The “resin fine particles B1” constituting the “resin fine particle dispersion B1” had a weight average molecular weight of 300,000, a softening point of 150 ° C., and a glass transition temperature of 70 ° C.

(2) Preparation of “resin fine particle dispersion B2 to B5” (a) Preparation of “resin fine particle dispersion B2” The monomer mixed solution [4] used in the preparation of “resin fine particle dispersion B1” is constituted. The amount of each compound added was changed as follows. That is,
Styrene 608 parts by weight n-butyl acrylate 197 parts by weight Methacrylic acid 74 parts by weight n-octyl mercaptan 0.20 parts by weight The same procedure except that the addition amount of each compound constituting each monomer mixed solution was changed as described above Thus, “resin fine particle dispersion B2” was prepared. The “resin fine particles B2” constituting the “resin fine particle dispersion B2” had a weight average molecular weight of 250,000, a softening point of 140 ° C., and a glass transition temperature of 60 ° C.

(B) Production of “resin fine particle dispersion B3” The addition amount of each compound constituting the monomer mixed solution [4] used in the production of “resin fine particle dispersion B1” was changed as follows. That is,
Styrene 665 parts by mass n-butyl acrylate 136 parts by mass Methacrylic acid 74 parts by mass n-octyl mercaptan 0.10 parts by mass The same procedure except that the addition amount of each compound constituting each monomer mixed solution was changed as described above Thus, “resin fine particle dispersion B3” was produced. The “resin fine particles B3” constituting the “resin fine particle dispersion B3” had a weight average molecular weight of 350,000, a softening point of 160 ° C., and a glass transition temperature of 80 ° C.

(C) Production of “resin fine particle dispersion B4” The addition amount of each compound constituting the monomer mixed solution [4] used in the production of “resin fine particle dispersion B1” was changed as follows. That is,
Styrene 538 parts by weight n-butyl acrylate 263 parts by weight Methacrylic acid 74 parts by weight n-octyl mercaptan 0.25 parts by weight The same procedure except that the addition amount of each compound constituting each monomer mixed solution was changed as described above To produce “resin fine particle dispersion B4”. The “resin fine particles B4” constituting the “resin fine particle dispersion B4” had a weight average molecular weight of 200,000, a softening point of 130 ° C., and a glass transition temperature of 50 ° C.

(D) Production of “resin fine particle dispersion B5” The addition amount of each compound constituting the monomer mixed solution [4] used in the production of “resin fine particle dispersion B1” was changed as follows. That is,
Styrene 685 parts by mass n-butyl acrylate 116 parts by mass Methacrylic acid 74 parts by mass n-octyl mercaptan 0.00 part by mass The same procedure except that the addition amount of each compound constituting each monomer mixed solution was changed as described above Thus, “resin fine particle dispersion B5” was prepared. The “resin fine particles B5” constituting the “resin fine particle dispersion B5” had a weight average molecular weight of 370,000, a softening point of 165 ° C., and a glass transition temperature of 85 ° C.

1-3. Preparation of “resin fine particle dispersions C1 to C5” (1) Preparation of “resin fine particle dispersion C1” An anionic surfactant (dodecylbenzene) was placed in a reaction vessel equipped with a stirrer, temperature sensor, cooling pipe, and nitrogen introducing device. A surfactant solution in which 2.0 parts by mass of sodium sulfonate (SDS) was dissolved in 2900 parts by mass of ion-exchanged water was added, and the internal temperature was raised to 80 ° C. while stirring at a stirring speed of 230 rpm under a nitrogen stream. I let you.

After adding 9.0 parts by mass of a polymerization initiator (potassium persulfate: KPS) to the surfactant solution and adjusting the internal temperature to 78 ° C,
Styrene 543 parts by mass n-butyl acrylate 228 parts by mass Methacrylic acid 105 parts by mass n-octyl mercaptan 24 parts by mass A monomer mixed solution [5] was added dropwise over 3 hours.

  After completion of the dropwise addition, the polymerization reaction was carried out by heating and stirring at 78 ° C. for 1 hour to prepare a dispersion of resin fine particles. This resin fine particle dispersion is referred to as “resin fine particle dispersion C1”. The “resin fine particles C1” constituting the “resin fine particle dispersion C1” had a weight average molecular weight of 10,000, a softening point of 110 ° C., and a glass transition temperature of 50 ° C.

(2) Preparation of “resin fine particle dispersion C2 to C5” (a) Preparation of “resin fine particle dispersion C2” Monomer mixed solution [5] used in the preparation of “resin fine particle dispersion C1” is configured. The amount of each compound added was changed as follows. That is,
Styrene 517 parts by mass n-butyl acrylate 254 parts by mass Methacrylic acid 105 parts by mass n-octyl mercaptan 48 parts by mass The same procedure except that the addition amount of each compound constituting each monomer mixed solution was changed as described above. Resin fine particle dispersion C2 "was prepared. The “resin fine particles C2” constituting the “resin fine particle dispersion C2” had a weight average molecular weight of 5,000, a softening point of 100 ° C., and a glass transition temperature of 45 ° C.

(B) Production of “resin fine particle dispersion C3” The addition amount of each compound constituting the monomer mixed solution [5] used in the production of “resin fine particle dispersion C1” was changed as follows. That is,
Styrene 562 parts by mass n-butyl acrylate 209 parts by mass Methacrylic acid 105 parts by mass n-octyl mercaptan 12 parts by mass The same procedure except that the addition amount of each compound constituting each monomer mixed solution was changed as described above. Resin fine particle dispersion C3 "was prepared. The “resin fine particles C3” constituting the “resin fine particle dispersion C3” had a weight average molecular weight of 20,000, a softening point of 120 ° C., and a glass transition temperature of 55 ° C.

(C) Production of “resin fine particle dispersion C4” The addition amount of each compound constituting the monomer mixed solution [5] used in the production of “resin fine particle dispersion C1” was changed as follows. That is,
Styrene 495 parts by weight n-butyl acrylate 276 parts by weight Methacrylic acid 105 parts by weight n-octyl mercaptan 71 parts by weight The same procedure except that the addition amount of each compound constituting each monomer mixed solution was changed as described above. Resin fine particle dispersion C4 "was prepared. The “resin fine particles C4” constituting the “resin fine particle dispersion C4” had a weight average molecular weight of 3,000, a softening point of 95 ° C., and a glass transition temperature of 40 ° C.

(D) Production of “resin fine particle dispersion C5” The addition amount of each compound constituting the monomer mixed solution [5] used in the production of “resin fine particle dispersion C1” was changed as follows. That is,
Styrene 604 parts by mass n-butyl acrylate 166 parts by mass Methacrylic acid 105 parts by mass n-octyl mercaptan 9 parts by mass The same procedure except that the addition amount of each compound constituting each monomer mixed solution was changed as described above. Resin fine particle dispersion C5 "was prepared. The “resin fine particles C5” constituting the “resin fine particle dispersion C5” had a weight average molecular weight of 25,000, a softening point of 130 ° C., and a glass transition temperature of 65 ° C.

  By the above procedure, “resin fine particles A1 to A5”, “resin fine particles B1 to B5”, and “resin fine particles C1 to C5” were produced.

1-4. Preparation of “Colorant Fine Particle Dispersion 1K” 90 parts by mass of sodium n-dodecyl sulfate was added to 1600 parts by mass of ion-exchanged water, and dissolved and stirred to prepare an aqueous surfactant solution. Subsequently, 420 parts by mass of carbon black “Regal 330R (manufactured by Cabot)” was gradually added to the surfactant aqueous solution while stirring. Next, a “colorant fine particle dispersion 1K” was prepared by performing a dispersion treatment using “Clearmix W Motion CLM-0.8 (M Technique Co., Ltd.)”.

  The particle size of the colorant fine particles in the “colorant fine particle dispersion 1K” was measured using an electrophoretic light scattering photometer “ELS-800” (manufactured by Otsuka Electronics Co., Ltd.). It was.

1-5. Preparation of “Toners 1-15” (1) Preparation of “Toner 1” “Toner 1” was prepared according to the following procedure.

(A) Formation of “core particle 1” (aggregation / fusion process)
In a reaction vessel equipped with a stirrer, temperature sensor, cooling pipe, nitrogen introduction device,
"Resin fine particle dispersion A1" 400 parts by mass (in terms of solid content)
"Resin fine particle dispersion B1" 21 parts by mass (solid content conversion)
900 parts by mass of ion-exchanged water “Colorant particle dispersion 1K” 200 parts by mass (in terms of solid content)
Was added and stirred. After adjusting the temperature in the reaction vessel to 30 ° C., a 5 mol / liter aqueous sodium hydroxide solution was added to adjust the pH to 8-11.

  Next, an aqueous solution in which 2 parts by mass of magnesium chloride hexahydrate was dissolved in 100 parts by mass of ion-exchanged water was added over 10 minutes at 30 ° C. with stirring. After standing for 3 minutes, the heating was started, and the system was heated to 65 ° C. over 60 minutes to associate the particles. In this state, the particle size of the associated particles was measured using “Multisizer 3 (manufactured by Beckman Coulter)”, and when the volume-based median diameter of the associated particles reached 5.5 μm, 40.2 parts by mass of sodium chloride The solution was dissolved in 1000 parts by mass of ion-exchanged water to stop the association.

  After termination of the association, the core temperature 1 was further produced by continuing the fusion by heating and stirring for 1 hour at a liquid temperature of 70 ° C. as an aging treatment.

(B) Shell formation (shell formation process)
Next, the dispersion of the “core particle 1” is set to 65 ° C., 47 parts by mass of the “resin fine particle dispersion C1” (in terms of solid content) is added, and 2 parts by mass of magnesium chloride hexahydrate is further added. An aqueous solution in which 1000 parts by mass of ion-exchanged water was dissolved was added over 10 minutes. Thereafter, the temperature was raised to a shelling temperature of 70 ° C. and stirring was continued for 1 hour to fuse the “resin fine particles C1” to the surface of the “core particles 1”, followed by aging treatment at 75 ° C. for 20 minutes. A shell was formed.

  Thereafter, an aqueous solution in which 40.2 parts by mass of sodium chloride was dissolved in 1000 parts by mass of ion-exchanged water was added to stop shell formation. Further, the colored particles produced by cooling to 30 ° C. at a rate of 8 ° C./min were filtered, washed repeatedly with ion exchange water at 45 ° C., and then dried with hot air at 40 ° C. In this manner, “colored particles 1” which are toner base particles having a shell of “resin fine particles C1” on the surface of “core particles 1” were produced.

(C) External Addition Treatment The following external additives were added to the produced “colored particles 1” and subjected to external addition treatment with “Henschel mixer (Mitsui Miike Mining Co., Ltd.)” to produce “Toner 1”. That is,
Silica treated with hexamethylsilazane (average primary particle size 12 nm)
0.6 part by mass n-octylsilane-treated titanium dioxide (average primary particle size 24 nm)
0.8 parts by mass The external addition treatment by the Henschel mixer was performed under the conditions of a peripheral speed of the stirring blade of 35 m / second, a treatment temperature of 35 ° C., and a treatment time of 15 minutes.

  By the above procedure, “Toner 1” containing three kinds of resins was produced.

(5) Production of “Toner 2-15” The combinations of “resin fine particle dispersion A1” and “resin fine particle dispersion B1” used in the production of “core particle 1” in the production of “toner 1” are shown in Table 1. As shown in FIG. 4, the resin fine particle dispersions A1 to A5 and the resin fine particle dispersions B1 to B5 were changed to be combined. Further, the “resin fine particles C1” used in the formation of the shell was changed to use any of “resin fine particles C1 to C5” as shown in Table 1.

  The addition amount of each resin fine particle dispersion when preparing each toner is the same as that of “Toner 1” except that the combination of resin fine particle dispersions is changed, such as the same addition amount as that of “Toner 1”. By taking the procedure, “Toners 2 to 15” containing three kinds of resins were prepared.

  Table 1 shows the weight average molecular weight Mw, softening point temperature Tsp, and glass transition temperature Tg of each resin fine particle (A1 to A5, B1 to B5, C1 to C5) used for the production of “Toners 1 to 15”.

2. Preparation of “Developers 1 to 15” Each of the “Toners 1 to 15” was mixed with a ferrite carrier having a volume average particle diameter of 50 μm coated with a silicone resin, and the “Developer 1 to 1” having a toner concentration of 6%. 15 "was prepared.

3. Evaluation Experiment With respect to “Toners 1 to 15” produced by the above procedure, the heat resistance storage stability, glossiness, gloss difference during continuous printing, low-temperature fixability, and crease fixing strength were evaluated. Here, “Examples 1 to 7” using “Toners 1 to 3, 6, 7, 10 and 11” and “Toners 4, 5, 8, 9, 12 to 15” using “Toners 1 to 3, 6, 7, 10 and 11” Comparative Examples 1 to 8 ”were designated.

  The evaluation other than the heat-resistant storage property of the toner is described in the above-mentioned commercially available composite printer “bizhub PRO C550 (manufactured by Konica Minolta Business Technologies, Inc.)” corresponding to the two-component development type image forming apparatus shown in FIG. Each of “Developers 1 to 15” was loaded. The evaluation by the image forming apparatus was performed in a so-called room temperature and normal humidity environment at a temperature of 20 ° C. and a relative humidity of 55% RH.

<Heat resistant storage>
The heat-resistant storage property is that the amount of agglomerates remaining on the sieve after 100 g of each of the toners prepared above was left for 24 hours under conditions of 55 ° C. and 90% RH and then sieved with a sieve having an opening of 45 μm. It was evaluated with. Among the following evaluation criteria, ◎ and ○ were accepted. That is,
Evaluation criteria:
A: Residual amount on the sieve is less than 5%, agglomeration amount is very small and heat-resistant storage property is excellent (a level where no agglomerates are generated even if transported in the summer without any heat insulating packing material)
○: Residual amount on the sieve is 5% or more and less than 20%, and the amount of agglomeration is small and heat-resistant storage stability is good.
X: The residual amount on the sieve is 20% or more, and the amount of agglomeration is large so that there is a practical problem (a level at which cold transport is required).

<Low temperature fixability>
The surface temperature of the heating roller of the image evaluation apparatus was changed in increments of 5 ° C. within a range of 90 to 130 ° C., and the occurrence of image contamination due to fixing offset was evaluated at each surface temperature. Specifically, an A4 size toner image that outputs a belt-like solid image having a width of 5 mm and a halftone image having a width of 20 mm in a direction perpendicular to the transfer paper with respect to the conveyance direction is laterally fed and conveyed, and a temperature region in which image contamination does not occur ( (Non-offset region) was detected and evaluated. That is,
Evaluation criteria:
A: The lower limit temperature of the non-offset region is 110 ° C. or lower, and the non-offset region is 15 ° C. or higher. ○: The lower limit temperature of the non-offset region is 120 ° C. or lower, and the non-offset region is lower than 15 ° C. ×: The lower limit temperature of the non-offset region is 125 ° C or higher.

<Fold crease strength>
The crease fixing strength was evaluated by measuring the toner fixing rate at the crease as described below. Here, the “fold fixing rate” is the fixing rate indicating the degree of toner peeling at the bent portion when the print image surface is folded. The solid image part (image density is 0.8) is folded inside and rubbed with a finger three times, then the image is opened and wiped three times with “JK Wiper” (manufactured by Crecia Co., Ltd.). This is a value calculated from the image density before and after the folding of the crease portion according to the following formula.

Fold fixing rate (%) = (image density after folding / image density before folding) × 100
The crease fixing strength was evaluated from the obtained crease fixing rate as shown in the following evaluation criteria. ◎ and ○ were accepted. That is,
Evaluation criteria:
A: The crease fixing rate is 90 to 100% and the crease fixing strength is excellent. ○: The crease fixing rate is less than 80 to 90% and the crease fixing strength is good. X: The crease fixing rate is less than 80% and the crease fixing strength is poor. .

<Glossiness>
The glossiness of the fixed image was evaluated by selecting a 75 ° measuring square type using a gloss meter “GMX-203 (Murakami Color Research Laboratory Co., Ltd.)” according to JIS Z8741. The glossiness is an average value of five points at the center and four corners of the measurement image. The fixing temperature when forming the gloss evaluation image was set to 160 ° C. Further, as a sheet for producing a fixed image, a commercially available A4 size glossy paper “POD Super Gloss 170 (manufactured by Oji Paper Co., Ltd.) (basis weight 128 g / m ² , thickness 0.17 mm)” was used. The evaluation was as follows, and ◎ and ○ were accepted. That is,
Evaluation criteria:
A: Gloss value is 70% or more. B: Gloss value is 60% or more and less than 70%. X: Gloss value is less than 60%.

<Gloss difference during continuous printing>
A continuous 1000 prints were made using A4 size paper, all solid images were produced on the first and 1000th continuous prints, and the glossiness of these images was measured to determine the difference. The glossiness measurement procedure is the same as the procedure performed in the “glossiness” evaluation. The evaluation was as follows, and ◎ and ○ were accepted. That is,
Evaluation criteria:
◎ 1% or less gloss difference between 1st sheet and 1000th sheet (no problem)
○: The above gloss difference is more than 1% and less than 5% (it is a level that is hardly understood by visual observation and has no problem).
X: The above gloss difference is 5% or more (this is a level where a difference can be seen even visually).
The results are shown in Table 2.

  As is apparent from the results shown in Table 2, “Examples 1 to 7” using the toner satisfying the constitution of the present invention have good results in low-temperature fixability, crease fix strength, heat-resistant storage stability, and It was confirmed that good image quality was obtained with high glossiness and a small difference in gloss during continuous printing. On the other hand, it was confirmed that none of “Comparative Examples 1 to 8” using toner that deviates from the configuration of the present invention has performance that satisfies all of the evaluation items.

1 (1Y, 1M, 1C, 1K) Photosensitive member 4 (4Y, 4M, 4C, 4K) Developing device 5 (5Y, 5M, 5C, 5K, 5A) Transfer roll 6 (6Y, 6M, 6C, 6K) Cleaning device 7 Intermediate transfer unit 24 Heat roll type fixing device 70 Intermediate transfer unit

Claims (5)

In an electrostatic charge image developing toner containing at least a binder resin, a colorant, and a wax,
The binder resin is
A resin (A) having a weight average molecular weight of 10,000 to 30,000, a softening point of 80 ° C. to 100 ° C., and a glass transition temperature of 30 ° C. to 40 ° C .;
A resin (B) having a mass average molecular weight of 250,000 to 350,000, a softening point of 140 ° C. to 160 ° C., and a glass transition temperature of 60 ° C. to 80 ° C .;
It is composed of a resin (C) having a mass average molecular weight of 5,000 to 20,000, a softening point of 100 ° C. to 120 ° C., and a glass transition temperature of 45 ° C. to 55 ° C. Toner for developing electrostatic image. The electrostatic image developing toner has a core-shell structure,
A binder resin composed of the resin (A) and the resin (B), a core composed of a colorant and a wax, and a shell composed of the binder resin composed of the resin (C). The electrostatic image developing toner according to claim 1, wherein   3. The electrostatic image developing toner according to claim 1, wherein the binder resin constituting the electrostatic image developing toner contains a vinyl resin. In the method for producing a toner for developing an electrostatic image containing at least a binder resin, a colorant, and a wax,
At least resin particles containing a resin (A) having a weight average molecular weight of 10,000 to 30,000, a softening point of 80 ° C. to 100 ° C., and a glass transition temperature of 30 ° C. to 40 ° C .;
After aggregating the resin particles containing the resin (B) having a mass average molecular weight of 250,000 to 350,000, a softening point of 140 ° C. to 160 ° C., and a glass transition temperature of 60 ° C. to 80 ° C.,
Through the step of aggregating resin particles containing resin (C) having a mass average molecular weight of 5,000 to 20,000, a softening point of 100 ° C. to 120 ° C., and a glass transition temperature of 45 ° C. to 55 ° C. A method for producing a toner for developing an electrostatic image, comprising producing a toner for developing an electrostatic image. After agglomerating the resin particles containing the resin (A) and the resin particles containing the resin (B) to form a core,
5. The electrostatic charge image according to claim 4, wherein the core surface is formed by agglomerating resin particles containing the resin (C) to form a shell, thereby producing an electrostatic charge image developing toner having a core-shell structure. A method for producing a developing toner.

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