JP2017054057A - Electrophotographic image forming method and electrophotographic image forming apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electrophotographic image forming method for achieving excellent separability in fixing, suppression of adhesion of loaded sheets, and reduction in fogging.SOLUTION: An electrophotographic image forming method of the present invention is an electrophotographic image forming method using, in a step of applying heat and pressure to a sheet carrying a toner for electrostatic charge image development to fix a toner image, means that injects air to the sheet to separate the sheet from a heat and pressure application part, where the toner for electrostatic charge image development contains at least a colorant, mold release agent, and amorphous resin and crystalline polyester resin as a binder resin, and the volume resistivity at 70°C of the toner for electrostatic charge image development is within a range of 1×10to 5×10Ω cm.SELECTED DRAWING: Figure 1

Description

  The present invention relates to an electrophotographic image forming method and an electrophotographic image forming apparatus. More specifically, the present invention relates to an electrophotographic image forming method in which a toner for developing an electrostatic charge image containing a crystalline polyester resin is used for fixing with a fixing device with air separation.

  In recent years, from the viewpoint of energy saving, development of a low-temperature fixing toner capable of fixing a toner image with less energy than conventional products has been promoted. In order to lower the toner fixing temperature, it is necessary to lower the melting temperature and the viscosity of the binder resin constituting the toner. However, since the paper is heated and melted when passing through the fixing nip portion, the paper may wrap around the surface of the fixing roller or the fixing belt due to the adhesive force of the toner and may not be separated, and paper jam may occur. In order to prevent paper wrapping in the fixing device, a technique related to an air separation mechanism for separating the paper from the fixing roller and the fixing belt by injecting air from the discharge port to the paper discharged from the nip portion has been proposed. (For example, refer to Patent Document 1).

Paper discharged by low-temperature fixing and air jet tends to be low-temperature, and when a high-print rate image is printed on both sides in such a process, the charge stored in the toner is not sufficiently released. . As a result, it has been found that a phenomenon occurs in which the images are charged, the images stick to each other, and the stacked paper having the image sticks.
Therefore, a technique that does not cause sticking of images even in a fixing device process equipped with an air separation mechanism has been desired.

For example, Patent Document 2 proposes that the image forming apparatus is provided with a humidifier, which humidifies the paper and suppresses curling and waviness of the paper. Since it was not obtained, improvement in performance is desired.
Further, although literatures defining the volume resistivity of the toner have been reported (see, for example, Patent Documents 3 and 4), both are defined from the viewpoint of charging stability, and are suitable for image sticking. The effect of was not obtained.

JP 2011-242429 A JP 2007-286151 A JP 2014-112191 A JP 2005-266546 A

  SUMMARY OF THE INVENTION The present invention has been made in view of the above problems and circumstances, and a solution to the problem is to provide an electrophotographic image forming method that achieves both excellent fixing and separating properties, suppression of sticking of stacked sheets, and little fogging. That is.

As a result of studying the cause of the above-mentioned problem in order to solve the above-mentioned problems, the present inventor carried the electrophotographic image forming method of the present invention with an electrostatic charge image developing toner (hereinafter also simply referred to as “toner”). An electrophotographic image forming method using means for spraying air onto the paper in a step of fixing the toner image by heating and pressurizing the applied paper, and separating the paper from the heating and pressurizing unit. The image developing toner contains at least a colorant, a releasing agent, and a non-crystalline resin and a crystalline polyester resin as a binder resin, and the volume resistivity of the electrostatic image developing toner at 70 ° C. is predetermined. In this range, the inventors have found that both excellent separation and separation properties and suppression of sticking of stacked sheets are achieved, and the present invention has been achieved.
That is, the said subject of this invention is solved by the following means.

1. Electrophotographic image formation using means for spraying air to the paper and separating the paper from the heating / pressurizing unit in the step of fixing the toner image by heating and pressurizing the paper carrying the electrostatic image developing toner. A method,
The electrostatic charge image developing toner contains at least a colorant, a release agent, and a non-crystalline resin and a crystalline polyester resin as a binder resin, and the volume resistivity of the electrostatic charge image developing toner at 70 ° C. Is in the range of 1 × 10 ^{13 to} 5 × 10 ¹⁶ Ω · cm.

  2. 2. The electrophotographic image forming method according to item 1, wherein the non-crystalline resin contains a non-crystalline polyester resin.

  3. 3. The electrophotographic image forming method according to item 2, wherein the non-crystalline resin further contains a styrene-acrylic resin.

  4). The crystalline polyester resin is contained within a range of 3 to 30% by mass with respect to the total amount of the binder resin, according to any one of items 1 to 3, Electrophotographic image forming method.

  5. The electrophotographic image forming method according to any one of Items 1 to 4, wherein the crystalline polyester resin contains a hybrid polyester resin formed by bonding with a different resin.

  6). An electrophotographic image forming apparatus comprising means for forming an image by the electrophotographic image forming method according to any one of items 1 to 5.

  By the above means of the present invention, it is possible to provide an electrophotographic image forming method that achieves both excellent fixing and separating properties, suppression of sticking of stacked sheets and little fogging.

The expression mechanism or action mechanism of the effect of the present invention is not clear, but is presumed as follows.
In order to improve the fixing separation property, a mechanism for preventing the image from being wound around the fixing roller by injecting air onto the sheet discharged from the fixing nip portion also includes a conventional image forming apparatus. When an image is fixed by a fixing device with air separation, the image is rapidly cooled by air, so that charges remain on the image after fixing. In the case of double-sided printing, the toner layer on the first side has a charge during secondary transfer, that is, a charge opposite to that of the toner. When sheets (images) are stacked in this state, the charges on the images on the second side of the nth sheet and the first side of the (n + 1) th sheet attract each other, so that the images are electrostatically attached to each other, and the paper is easy to cut. It gets worse.

In addition, when the image is cooled by lowering the fixing temperature and air jet, etc., the amount of charge remaining on the image increases due to the volume resistivity of the toner (image) that increases as the image temperature decreases. There was a tendency for paper sticking to deteriorate.
Since the crystalline polyester resin generally has a tendency to have a low volume resistivity even at room temperature, there is a difference in the volume resistivity of the toner with and without the addition of the crystalline polyester resin, but the glass transition point (Tg) of the toner. The difference becomes more prominent in the high temperature region. The definition of the volume resistivity at 70 ° C. assumes an image temperature higher than the glass transition point of the toner and after the image is fixed and air-jetted.
When the volume resistivity at 70 ° C. is less than 1 × 10 ¹³ Ω · cm, the charge amount is lowered and the fogging performance is lowered. On the other hand, when the volume resistivity is larger than 5 × 10 ¹⁶ Ω · cm, the sticking force between the papers becomes strong, and the paper is not easily cut.
Therefore, by forming an electrophotographic image using a toner having a volume resistivity within a predetermined range used in the present invention, it is possible to suppress sticking while preventing wrapping by air jetting, and a good image with little fogging. I guess it can be obtained.

Schematic sectional view of the electrophotographic image forming apparatus of the present invention Schematic sectional view of a fixing device used in the present invention Schematic explaining the measurement of sticking force

In the electrophotographic image forming method of the present invention, in a step of fixing a toner image by heating and pressurizing a sheet carrying a toner for developing an electrostatic image, air is jetted on the sheet, and the sheet is heated from the heating and pressing unit. An electrophotographic image forming method using a means for separating the toner, wherein the electrostatic image developing toner contains at least a colorant, a release agent, and a non-crystalline resin and a crystalline polyester resin as a binder resin, The volume resistivity of the toner for developing an electrostatic charge image at 70 ° C. is in the range of 1 × 10 ^{13 to} 5 × 10 ¹⁶ Ω · cm. This feature is a technical feature common to or corresponding to the inventions according to claims 1 to 6.

The amorphous resin according to the present invention is preferable in that it contains a non-crystalline polyester resin, so that the volume resistivity can be lowered and resistance to heat can be easily reduced.
Further, the amorphous resin is preferable because it further contains a styrene-acrylic resin so that the volume resistivity of the toner can be easily controlled.

The crystalline polyester resin according to the present invention is preferable in that the volume resistivity of the toner can be more easily controlled by being contained in the range of 3 to 30% by mass with respect to the total amount of the binder resin.
In addition, the crystalline polyester resin is preferable in that it contains a hybrid polyester resin bonded to a different resin, so that the crystalline polyester resin can easily become compatible with the amorphous resin and the molecular chains of the crystalline resin can be easily arranged.

  The electrophotographic image forming apparatus of the present invention preferably includes means for forming an image by the electrophotographic image forming method of the present invention from the viewpoint of manifesting the effects of the present invention.

  Hereinafter, the present invention, its components, and modes and modes for carrying out the present invention will be described in detail. In addition, "-" shown in the following description is used with the meaning which includes the numerical value described before and behind that as a lower limit and an upper limit.

[Outline of electrophotographic image forming method]
In the electrophotographic image forming method of the present invention, in a step of fixing a toner image by heating and pressurizing a sheet carrying a toner for developing an electrostatic image, air is jetted on the sheet, and the sheet is heated from the heating and pressing unit. An electrophotographic image forming method using a means for separating the toner, wherein the electrostatic image developing toner contains at least a colorant, a release agent, and a non-crystalline resin and a crystalline polyester resin as a binder resin, The volume resistivity of the toner for developing an electrostatic charge image at 70 ° C. is in the range of 1 × 10 ^{13 to} 5 × 10 ¹⁶ Ω · cm.
As a specific outline of the electrophotographic image forming method, a heating member that heats a paper carrying a toner image and a nip portion that sandwiches the paper carrying a toner image are brought into contact with the heating member to contact the paper. A fixing device having a heating member for fixing an image and means for separating the paper from the heating member by injecting air onto the paper discharged from the nip portion is used.
Details of the electrophotographic image forming apparatus, the fixing device, and the toner used in the present invention will be described in order.

[Outline of electrophotographic image forming apparatus]
FIG. 1 is an overall configuration diagram of an electrophotographic image forming apparatus (hereinafter also simply referred to as an image forming apparatus) X using the electrophotographic image forming method of the present invention.
The image forming apparatus X includes an image forming apparatus main body GH and an image reading apparatus YS. The image forming apparatus main body GH includes a plurality of sets of image forming units 10Y, 10M, 10C, and 10K, a belt-shaped intermediate transfer belt 5, a paper feeding / conveying unit, a fixing device 8, and the like.
An image reading device YS including an automatic document feeder 201 and a document image scanning exposure device 202 is installed on the upper part of the image forming apparatus main body GH. The document d placed on the document table of the automatic document feeder 201 is transported by the transport unit, and an image on one or both sides of the document d is scanned and exposed by the optical system of the document image scanning exposure device 202, and the line image sensor CCD is scanned. Is read.

The signal formed by photoelectric conversion by the line image sensor CCD is subjected to analog processing, A / D conversion, shading correction, image compression processing, and the like in the image processing unit, and then the exposure units 3Y, 3M, 3C, and 3K. Sent to.
In the image forming unit 10Y that forms a yellow (Y) image, a charging unit 2Y, an exposure unit 3Y, a developing unit 4Y, and a cleaning unit 7Y are arranged around the photosensitive drum 1Y. The image forming units 10M, 10C, and 10K have substantially the same configuration as the image forming unit 10Y. The developing units 4Y, 4M, 4C, and 4K include a two-component developer including yellow (Y), magenta (M), cyan (C), and black (K) toner having a small particle diameter and a carrier. The toner includes, for example, a pigment or dye serving as a colorant, a release agent that helps the toner peel from the fixing belt 81 after fixing, and a binder resin that holds them.

The intermediate transfer belt 5 is wound around a plurality of rollers and is rotatably supported.
The fixing device 8 heats and presses the toner image of the paper P at a nip portion formed between the heated fixing belt 81 and the pressure roller 84 and fixes the toner image.
Each color image formed by the image forming units 10Y, 10M, 10C, and 10K is sequentially transferred to the rotating intermediate transfer belt 5 by the transfer units 6Y, 6M, 6C, and 6K, thereby forming a color toner image. . The paper P stored in the paper feed cassette 20 is fed by the paper feed unit 21 and is conveyed to the transfer unit 6A through the paper feed rollers 22A, 22B, 22C, 22D, the registration roller 23, and the like. A color toner image is transferred. The sheet P on which the color toner image is transferred is heated and pressurized in the fixing device 8, and the color toner image is fixed on the sheet P. Thereafter, the sheet is sandwiched between the sheet discharge rollers 24 and placed on the sheet discharge tray 25.
After the color toner image is transferred onto the paper P by the transfer unit 6A, the toner remaining on the intermediate transfer belt 5 from which the paper P has been peeled is removed by the cleaning unit 7A.

[Outline of fixing device]
FIG. 2 is an enlarged cross-sectional view of the fixing device 8.
The fixing device 8 includes a fixing frame 8F having an outer frame made up of a plurality of frame members. Each member constituting the fixing device 8 is supported by the fixing frame 8F directly or indirectly. The fixing frame 8F is movably supported by a guide mechanism such as a slide rail, and the fixing device 8 can be pulled out of the image forming apparatus X in the front direction (the front side in FIG. 1 and FIG. 2). .

The fixing belt 81 as a heating member is formed in an endless shape. For example, PI (polyimide) having a thickness of 70 μm is used as a base, and heat-resistant silicon rubber having a thickness of 200 μm is used as an elastic layer (hardness JIS-). A surface is coated with PFA (perfluoroalkoxy), which is a heat-resistant resin having a thickness of 30 μm.
The fixing belt 81 is stretched between the heating roller 82 and the fixing roller 83.
The heating roller 82 has a built-in halogen heater 82A for heating the fixing belt 81. For example, a resin in which the outer peripheral surface of a cylindrical cored bar 82B formed of aluminum or the like is coated with 30 μm thick PTFE. Covered with layer 82C. The halogen heater 82A is composed of, for example, two of 1200 W, two of 750 W, and one of 500 W in order to cope with different paper widths, and different heat generation distributions in the axial direction corresponding to different paper widths of the paper. It is arranged to be.

  The fixing roller 83 is disposed to face the pressure roller 84 in order to form a nip portion N between the fixing belt 81 and the pressure roller 84. That is, in this embodiment, the pressure roller 84 corresponds to the pressure member in the present invention. The fixing roller 83 is made of a solid metal core 83A formed of a metal such as iron, which is coated with a heat-resistant silicon rubber having a thickness of 20 mm as an elastic layer 83B, and is further made of a heat-resistant resin with a low friction of 30 μm. It is covered with a resin layer 83C coated with some PTFE.

Around the heating roller 82, a temperature detection sensor SE that detects the temperature of the fixing belt 81 in a non-contact state with the fixing belt 81 is provided. The ON / OFF control of the halogen heater 82A is performed based on the detection result of the temperature detection sensor SE, and the fixing belt 81 is maintained at a temperature suitable for the fixing operation.
The pressure roller 84 in contact with the fixing belt 81 incorporates a halogen heater 84A as a heating means in order to shorten the heating time immediately after the power supply to the image forming apparatus X is turned on, and is a cylinder having a thickness of 4 mm formed from aluminum or the like. The outer peripheral surface of the metal core 84B is covered with a 1 mm thick heat-resistant silicon rubber (hardness JIS-A 30 °) as an elastic layer 84C, and further covered with a resin layer 84D of a 30 μm thick PFA tube. Yes. The outer diameter is 90 mm. The pressure roller 84 is pressed against the fixing belt 81 and the fixing roller 83 by an urging means (not shown).

In the above configuration, when the pressure roller 84 is rotated counterclockwise (x direction in FIG. 2) by a driving unit (not shown), the fixing belt 81, the heating roller 82, and the fixing roller 83 are rotated clockwise (y direction in FIG. 2). ) Rotate and rotate.
The fixing belt 81 is heated by the halogen heater 82A through the heating roller 82 that is in contact, and the pressure roller 84 is also heated by the halogen heater 84A. The fed paper is heated and pressurized at the nip portion N formed between the fixing belt 81 wound around the fixing roller 83 and the pressure roller 84 to fix the toner image on the paper. The

[Outline of air separation mechanism]
In the fixing device 8, an air separation unit that blows air against the paper discharged from the nip portion N to separate the paper from the fixing belt 81 is installed as a cooling unit. The air separation unit includes the suction fan F, the first duct 121, and the second duct 131 shown in FIG.
The first duct 121 is formed of an elastic flexible member, and the second duct 131 is formed of a metal such as iron. The end portion of the first duct 121 is fixed to the end portion of the second duct 131, and the first duct 121 is deformed even when the second duct 131 is movable, as will be described later, and the opening portion 121 b of the first duct 121. And air does not leak from between the opening 131a of the second duct 131.

As shown in FIG. 2, the opening 121a of the first duct 121 is connected to the suction fan F directly or via a communication duct (not shown). The other opening 121 b of the first duct 121 is connected to the opening 131 a of the second duct 131.
The discharge port 131b, which is the other opening of the second duct 131, is installed near the nip N. Air sent from the suction fan F flows through the first duct 121 and the second duct 131 in the direction of the arrow shown in FIG. 2 and is discharged from the discharge port 131b, and near the leading edge of the paper discharged from the nip portion N. And sprayed. As a result, air enters between the paper and the fixing belt 81, and the paper is appropriately separated from the fixing belt 81, thereby preventing the paper from being wound. In addition, by separating the paper from the fixing belt 81 by the air separation unit including the suction fan F, the first duct 121, and the second duct 131, a member such as a separation claw is not brought into contact with the surface of the fixing belt 81. Since the paper can be separated, the surface of the fixing belt 81 is not damaged.
The paper separated from the fixing belt 81 by the air separation unit is guided by the upper guide 211, the lower guide 212, and 213, and is sandwiched by the transport rollers R1 and R2 and is located on the downstream side in the transport direction of the fixing device 8. It is conveyed in the direction of 24 (see FIG. 1).

[Toner for electrostatic image development]
The electrostatic image developing toner according to the present invention contains at least a colorant, a release agent, and a non-crystalline resin and a crystalline polyester resin as a binder resin, and the electrostatic image developing toner at 70 ° C. The volume resistivity is in the range of 1 × 10 ^{13 to} 5 × 10 ¹⁶ Ω · cm.
Details of the physical properties and configuration of the toner according to the present invention will be described. The “toner” according to the present invention contains “toner base particles”. The “toner base particles” are referred to as “toner particles” by adding an external additive. The “toner” means an aggregate of “toner particles”.

[Volume resistivity]
Since the crystalline polyester resin generally tends to have a low volume resistivity even at room temperature, there is a difference in the volume resistivity of the toner with and without the addition of the crystalline polyester, but the glass transition point (hereinafter also referred to as Tg) of the toner. )), The difference becomes more remarkable in the temperature range higher than the glass transition point.
The regulation of the volume resistivity at 70 ° C. assumes an image temperature higher than the Tg of the toner and after the image is fixed and air-jetted.

The glass transition point of the toner is preferably 40 to 70 ° C, more preferably 45 to 65 ° C. When it is lower than 40 ° C., the heat resistance is inferior, and when it is higher than 70 ° C., the fixing property is inferior.
Further, the volume resistivity of the toner at 70 ° C. is in the range of 1 × 10 ^{13 to} 5 × 10 ¹⁶ Ω · cm, and more preferably in the range of 5 × 10 ¹³ to 1 × 10 ¹⁶ Ω · cm. . That is, when the volume resistivity is less than 1 × 10 ¹³ Ω · cm, the charge amount is lowered and the fogging performance is lowered. On the other hand, if it is larger than 5 × 10 ¹⁶ Ω · cm, the sticking force between the papers becomes strong, and the paper's cutability deteriorates. From the viewpoint of fogging, the volume resistivity at room temperature is preferably in the range of 5 × 10 ^{15 to} 3 × 10 ¹⁸ Ω · cm.

The volume resistivity of the crystalline polyester to be used is desirably in the range of 1 × 10 ¹⁰ to 1 × 10 ¹⁴ Ω · cm.
In order to keep the volume resistivity within a specified range, it is better that the crystalline polyester is uniformly dispersed in the toner. For this purpose, the dispersed particle diameter of the crystalline polyester is desirably in the range of 100 to 300 nm, more preferably in the range of 150 to 250 nm. By controlling the dispersed particle diameter, the crystalline polyester resin can be uniformly dispersed in the toner. Here, “uniformly disperse” means that the conductive path of the crystalline polyester cannot be formed.

(Toner base particles)
The toner base particles used in the present invention contain an amorphous resin and a crystalline polyester resin as a binder resin (binder resin). The toner base particles may contain other toner constituents such as magnetic powder and a charge control agent. The toner base particles used in the present invention are preferably those obtained by a wet manufacturing method (for example, an emulsion aggregation method) prepared in an aqueous medium.

<Binder resin (non-crystalline resin and crystalline resin)>
The toner base particles used in the present invention include an amorphous resin and a crystalline polyester resin as a binder resin (binder resin).
The mass ratio of the amorphous resin to the crystalline resin (noncrystalline resin / crystalline resin) is preferably in the range of 97/3 to 70/30, more preferably 95/5 to 75/25. Is within the range. By defining the amount of the crystalline polyester, the volume resistivity can be easily controlled in a more preferable range.

[Amorphous resin]
There is no particular limitation on the amorphous resin, and any conventionally known amorphous resin in this technical field can be used. Among them, the amorphous resin preferably contains an amorphous vinyl resin. When the amorphous resin contains a vinyl resin, a toner having excellent plasticity at the time of heat fixing can be provided.
Here, the “vinyl resin” is a resin obtained by polymerization using at least a vinyl monomer.

Specific examples of the amorphous vinyl resin include acrylic resins and styrene-acrylic resins. Among these, as the non-crystalline vinyl resin, a styrene-acrylic resin formed using a styrene monomer and a (meth) acrylic acid ester monomer is preferable.
When a styrene-acrylic resin is used, the ratio of the styrene-acrylic resin is preferably in the range of 55 to 85% by mass of the whole toner. More preferably, it exists in the range of 60-80 mass%. By adjusting within this range, the volume resistivity of the toner can be controlled.
As the vinyl monomer forming the non-crystalline vinyl resin, one or more selected from the following can be used.

(1) Styrene monomer As the styrene monomer, styrene, o-methylstyrene, m-methylstyrene, p-methylstyrene, α-methylstyrene, p-phenylstyrene, p-ethylstyrene, 2, 4-dimethylstyrene, p-tert-butylstyrene, pn-hexylstyrene, pn-octylstyrene, pn-nonylstyrene, pn-decylstyrene, pn-dodecylstyrene, and derivatives thereof Etc.

(2) (Meth) acrylic ester monomers As (meth) acrylate monomers, methyl (meth) acrylate, ethyl (meth) acrylate, n-butyl (meth) acrylate, ( (Meth) acrylic acid isopropyl, (meth) acrylic acid isobutyl, (meth) acrylic acid t-butyl, (meth) acrylic acid n-octyl, (meth) acrylic acid 2-ethylhexyl, (meth) acrylic acid stearyl, (meth) Examples include lauryl acrylate, phenyl (meth) acrylate, diethylaminoethyl (meth) acrylate, dimethylaminoethyl (meth) acrylate, and derivatives thereof.

(3) Vinyl ester-based monomer Examples of the vinyl ester-based monomer include vinyl propionate, vinyl acetate, and vinyl benzoate.

(4) Vinyl ether monomers Monomers include vinyl methyl ether and vinyl ethyl ether.

(5) Vinyl ketone monomer Examples of the vinyl ketone monomer include vinyl methyl ketone, vinyl ethyl ketone, and vinyl hexyl ketone.

(6) N-vinyl monomer Examples of the N-vinyl monomer include N-vinyl carbazole, N-vinyl indole, and N-vinyl pyrrolidone.

(7) Others As other types of monomers, vinyl compounds such as vinyl naphthalene and vinyl pyridine, acrylic acid or methacrylic acid derivatives such as acrylonitrile, methacrylonitrile, and acrylamide can be used.

Moreover, as a vinyl-type monomer, it is preferable to use the monomer which has ionic dissociation groups, such as a carboxy group, a sulfonic acid group, a phosphoric acid group, for example. Specific examples include the following.
Examples of the monomer having a carboxy group include acrylic acid, methacrylic acid, maleic acid, itaconic acid, cinnamic acid, fumaric acid, maleic acid monoalkyl ester, itaconic acid monoalkyl ester, and the like. Examples of the monomer having a sulfonic acid group include styrene sulfonic acid, allyl sulfosuccinic acid, and 2-acrylamido-2-methylpropane sulfonic acid. Furthermore, examples of the monomer having a phosphate group include acid phosphooxyethyl methacrylate.

  Furthermore, polyfunctional vinyls can be used as the vinyl monomer, and the non-crystalline vinyl resin can have a crosslinked structure. Polyfunctional vinyls include divinylbenzene, ethylene glycol dimethacrylate, ethylene glycol diacrylate, diethylene glycol dimethacrylate, diethylene glycol diacrylate, triethylene glycol dimethacrylate, triethylene glycol diacrylate, neopentyl glycol dimethacrylate and neopentyl glycol. Examples include diacrylate.

The vinyl resin has been described in detail as a preferred form of the amorphous resin, but it is also preferable that the amorphous resin includes an amorphous polyester resin.
In general, volume resistivity is determined by chemical structure and thermal characteristics. The amorphous polyester resin has many hydroxy groups that tend to lower the volume resistivity, and since the temperature difference from the glass transition point to the softening point is small, the molecular motion rapidly becomes active with respect to the temperature. Therefore, it has the property of easily reducing resistance to heat.
Specifically, the hydroxyl value of the non-crystalline polyester resin is preferably in the range of 20 to 50 mgKOH / g, and the increase in volume resistivity can be suppressed by setting it to 20 mgKOH or more, and by setting it to 50 mgKOH or less. The water absorption of the resin can be controlled within an appropriate range, and the charging performance can be maintained appropriately.
Here, the hydroxyl value refers to the number of mg of potassium hydroxide necessary to neutralize acetic acid bound to acetylated compounds contained in 1 g of a resin or the like. It is calculated from the amount of neutralization obtained by dissolving in titania and titrating with a potassium hydroxide solution whose titer has been confirmed accurately. Specific methods for measuring the hydroxyl value include, for example, the method described in JIS 0070-1992.

The glass transition point (Tg) of the amorphous resin is preferably in the range of 40 to 70 ° C, more preferably in the range of 45 to 65 ° C. When the glass transition point of the amorphous resin is in the range, sufficient low-temperature fixing property and heat-resistant storage property can be obtained at the same time.
The glass transition point (Tg) of the amorphous resin is a value measured using “Diamond DSC” (Perkin Elmer).

  As a measurement procedure, 3.0 mg of a measurement sample (noncrystalline resin) is sealed in an aluminum pan and set in a holder. The reference used an empty aluminum pan. The measurement conditions were a temperature range of 0 to 200 ° C., a temperature increase rate of 10 ° C./min, a temperature decrease rate of 10 ° C./min, and heat-cool-heat temperature control. Perform analysis based on the data in Heat, draw 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 its intersection Is the glass transition point.

  The molecular weight of the amorphous resin measured by gel permeation chromatography (GPC) is preferably in the range of 10,000 to 100,000 in terms of weight average molecular weight (Mw). In this invention, the molecular weight by GPC of an amorphous resin is a value measured as follows. That is, using an apparatus “HLC-8120GPC” (manufactured by Tosoh Corporation) and a column “TSKguardcolumn + TSKgelSuperHZ-M3 series” (manufactured by Tosoh Corporation), while maintaining the column temperature at 40 ° C., tetrahydrofuran (THF) was used as a carrier solvent at a flow rate of 0. The sample to be measured (non-crystalline resin) was dissolved in tetrahydrofuran so as to have a concentration of 1 mg / mL under a dissolution condition in which the measurement sample (noncrystalline resin) was treated for 5 minutes using an ultrasonic disperser at room temperature. A sample solution is obtained by processing with a 2 μm membrane filter, and 10 μL of this sample solution is injected into the apparatus together with the carrier solvent, detected using a refractive index detector (RI detector), and the molecular weight distribution of the measurement sample. A calibration curve measured using monodisperse polystyrene standard particles Is used to calculate. Ten polystyrenes are used for calibration curve measurement.

[Crystalline polyester resin]
“Crystalline polyester resin” means a differential scanning among known polyester resins obtained by polycondensation reaction of divalent or higher carboxylic acid (polyvalent carboxylic acid) and divalent or higher alcohol (polyhydric alcohol). In calorimetry (DSC), it refers to a resin having a clear endothermic peak rather than a stepwise endothermic change. The clear endothermic peak specifically means a peak in which the half-value width of the endothermic peak is within 15 ° C. when measured at a rate of temperature increase of 10 ° C./min in differential scanning calorimetry (DSC). To do.

  The polyvalent carboxylic acid is a compound containing two or more carboxy groups in one molecule. Specifically, for example, oxalic acid, malonic acid, succinic acid, adipic acid, sebacic acid, azelaic acid, n-dodecyl succinic acid, nonanedicarboxylic acid, decanedicarboxylic acid, undecanedicarboxylic acid, dodecanedicarboxylic acid, tetradecanedicarboxylic acid Saturated aliphatic dicarboxylic acids such as cycloaliphatic dicarboxylic acids such as cyclohexanedicarboxylic acid, aromatic dicarboxylic acids such as phthalic acid, isophthalic acid and terephthalic acid, and more than trivalent polyvalent carboxylic acids such as trimellitic acid and pyromellitic acid Acid; and anhydrides of these carboxylic acid compounds or alkyl esters having 1 to 3 carbon atoms. These may be used individually by 1 type and may be used in combination of 2 or more type.

  A polyhydric alcohol is a compound containing two or more hydroxy groups in one molecule. Specifically, for example, 1,2-propanediol, 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,7-heptanediol, 1 , 8-octanediol, 1,9-nonanediol, dodecanediol, neopentylglycol, 1,4-butenediol, and other aliphatic diols; trivalent or more polyvalent such as glycerin, pentaerythritol, trimethylolpropane, sorbitol Examples include alcohol. These may be used individually by 1 type and may be used in combination of 2 or more type.

The crystalline polyester resin preferably contains a hybrid polyester resin formed by bonding with a different resin. This is because the vinyl-based polymer segment introduced into the hybrid polyester resin has a high affinity with the amorphous resin, so that the hybrid crystalline resin easily becomes compatible with the amorphous resin. Therefore, when the crystalline polyester resin contains a hybrid polyester resin, the molecular chains of the crystalline resin are easily arranged. As a result, the volume resistivity of the toner is controlled within the range of 1 × 10 ^{13 to} 5 × 10 ¹⁶ Ω · cm even when the mass% introduced by the hybrid polyester resin is lower than that of the non-hybrid crystalline resin. It becomes easy.

  It is preferable that melting | fusing point (Tm) of crystalline polyester resin (Hybrid crystalline polyester resin and the non-hybrid crystalline polyester resin mentioned later) is 55-90 degreeC, More preferably, it is 70-85 degreeC. When the melting point of the crystalline polyester resin is in the above range, sufficient low-temperature fixability and excellent hot offset resistance can be obtained. The melting point of the crystalline polyester resin can be controlled by the resin composition.

  In the present invention, the melting point of the crystalline polyester resin is a value measured as follows. That is, using a differential scanning calorimeter “Diamond DSC” (manufactured by PerkinElmer Co., Ltd.), a first temperature raising process in which the temperature is raised from 0 ° C. to 200 ° C. at an elevation rate of 10 ° C./min, It is measured by the measurement conditions (temperature increase / cooling conditions) that pass through the cooling process for cooling from 0 to 0 ° C. and the second temperature increasing process for increasing the temperature from 0 ° C. to 200 ° C. at a rate of 10 ° C./min. The endothermic peak top temperature derived from the crystalline polyester resin in the first temperature raising process is defined as the melting point (Tm) based on the DSC curve obtained by this measurement. As a measurement procedure, 3.0 mg of a measurement sample (crystalline polyester resin) is sealed in an aluminum pan and set in a diamond DSC sample holder. The reference uses an empty aluminum pan.

The molecular weight of the crystalline polyester resin measured by gel permeation chromatography (GPC) is 5000 to 50000 in terms of weight average molecular weight (Mw) and 1500 to 25000 in terms of number average molecular weight (Mn). preferable. The molecular weight measured by GPC of the crystalline polyester resin is measured in the same manner as described above except that the crystalline polyester resin is used as a measurement sample.
The mass ratio of the noncrystalline resin to the crystalline resin (noncrystalline resin / crystalline resin) is preferably 97/3 to 70/30, more preferably 95/5 to 75/25. By setting the mass ratio (non-crystalline resin / crystalline resin) within the above range, the volume resistivity of the toner at 70 ° C. should be in the range of 1 × 10 ^{13 to} 5 × 10 ¹⁶ Ω · cm. Becomes easy.

  A crystalline polyester resin is a crystalline polyester resin formed by chemically bonding a vinyl polymer segment and a polyester polymer segment (hereinafter referred to simply as “hybrid crystal polyester resin having a plurality of such segments”). And the crystalline resin having no plurality of segments is also simply referred to as “non-hybrid crystalline resin”). At this time, the vinyl polymer segment and the polyester polymer segment are preferably a crystalline polyester resin bonded via both reactive monomers. In addition, the said polyester polymerization segment is comprised from crystalline polyester resin.

[Vinyl polymer segment]
The vinyl polymer segment constituting the hybrid crystalline resin is composed of a resin obtained by polymerizing a vinyl monomer. Here, as the vinyl monomer, those described above as the monomers constituting the vinyl resin can be used in the same manner, and thus detailed description thereof is omitted here. Although there is no particular limitation on the content of the vinyl polymer segment in the hybrid crystalline resin (hybridization rate (“HB rate” described in the examples described later)), the hybridization rate of the hybrid crystalline resin is It is preferably 40% by mass or more, more preferably 40 to 60% by mass, and further preferably 45 to 50% by mass.

[Polyester polymerization segment]
The polyester polymerization segment constituting the hybrid resin is composed of a crystalline polyester resin produced by performing a polycondensation reaction between a polyvalent carboxylic acid and a polyhydric alcohol in the presence of a catalyst. Here, specific types of the polyvalent carboxylic acid and the polyhydric alcohol are as described above.

[Amotropic monomer]
“Amotropic monomer” is a monomer that binds a polyester polymer segment and a vinyl polymer segment, and in the molecule, a hydroxy group, a carboxy group, an epoxy group, a primary polymer that forms a polyester polymer segment. It is a monomer having both a group selected from an amino group and a secondary amino group and an ethylenically unsaturated group forming a vinyl polymerized segment. Both reactive monomers are preferably monomers having a hydroxy group or a carboxy group and an ethylenically unsaturated group. More preferably, it is a monomer having a carboxy group and an ethylenically unsaturated group. That is, it is preferably a vinyl carboxylic acid.
Specific examples of the both reactive monomers include, for example, acrylic acid, methacrylic acid, fumaric acid, maleic acid and the like, and even these hydroxyalkyl (1 to 3 carbon atoms) esters. Acrylic acid, methacrylic acid or fumaric acid is preferred from the viewpoint of reactivity. The polyester polymer segment and the vinyl polymer segment are bonded through the both reactive monomers.
From the viewpoint of improving the low-temperature fixability, high-temperature offset resistance and durability of the toner, the amount of the both reactive monomers used is based on 100 parts by mass of the total amount of vinyl monomers constituting the vinyl polymer segment. 1-10 mass parts is preferable and 4-8 mass parts is more preferable.

[Method for producing hybrid crystalline resin]
An existing general scheme can be used as a method for producing the hybrid crystalline resin. The following three methods are listed as typical methods.
(1) A polyester polymerization segment is preliminarily polymerized, and both reactive monomers are reacted with the polyester polymerization segment, and an aromatic vinyl monomer for forming a vinyl polymerization segment and (meth) A method of forming a hybrid crystalline resin by reacting an acrylic ester monomer.
(2) A vinyl polymer segment is polymerized in advance, the vinyl polymer segment is reacted with both reactive monomers, and further reacted with a polyvalent carboxylic acid and a polyhydric alcohol to form a polyester polymer segment. A method for forming a polyester polymer segment by causing the polyester polymer segment to form.
(3) A method in which a polyester polymer segment and a vinyl polymer segment are polymerized in advance, and then both reactive monomers are reacted with each other to bond them together.

In the present invention, any of the above production methods can be used, but the method of the above item (2) is preferred. Specifically, the polyhydric carboxylic acid and polyhydric alcohol forming the polyester polymerization segment, the vinyl monomer forming the vinyl polymerization segment and the both reactive monomers are mixed, and a polymerization initiator is added. It is preferable to carry out a polycondensation reaction by adding an esterification catalyst after addition polymerization of a vinyl monomer and an amphoteric monomer to form a vinyl polymer segment.
Here, as a catalyst for synthesizing the polyester polymerization segment, various conventionally known catalysts can be used. In addition, examples of the esterification catalyst include tin compounds such as dibutyltin oxide and tin (II) 2-ethylhexanoate, and titanium compounds such as titanium diisopropylate bistriethanolamate. Acid (3,4,5-trihydroxybenzoic acid) and the like.

<Release agent (offset prevention agent)>
In the toner according to the present invention, when the toner base particles are configured to contain a release agent, the release agent is particularly contained in the amorphous resin from the viewpoint of surface exudation of the release agent during fixing. Is preferred.
As the wax, polyolefin waxes such as low molecular weight polypropylene, polyethylene, or oxidized polypropylene, polyethylene, and ester waxes such as behenyl behenate can be preferably used.
Specifically, polyolefin waxes such as polyethylene wax and polypropylene wax; branched chain hydrocarbon waxes such as microcrystalline wax; long chain hydrocarbon waxes such as paraffin wax and sazol wax; dialkyls such as distearyl ketone Ketone wax; carnauba wax, montan wax, behenyl behenate, trimethylolpropane tribehenate, pentaerythritol tetrabehenate, pentaerythritol diacetate dibehenate, glycerin tribehenate, 1,18-octadecanedioldi Ester waxes such as stearate, trimellitic trimellitic acid and distearyl maleate; ethylenediamine behenylamide, trimellitic acid tristearylamide, etc. Such as amide waxes.
Among these, from the viewpoint of releasability at low-temperature fixing, it is preferable to use those having a low melting point, specifically those having a melting point in the range of 40 to 90 ° C. The content of the releasing agent is preferably 1 to 20% by mass in the toner base particles, and more preferably 5 to 20% by mass.

<Colorant>
Examples of carbon black include channel black, furnace black, acetylene black, thermal black, and lamp black. Examples of black iron oxide include magnetite, hematite, and iron iron trioxide.
Examples of the dye include C.I. I. Solvent Red 1, 49, 52, 58, 63, 111, 122, C.I. I. Solvent Yellow 19, 44, 77, 79, 81, 82, 93, 98, 103, 104, 112, 162, C.I. I. Solvent Blue 25, 36, 60, 70, 93, 95 and the like.
Examples of the pigment include C.I. I. Pigment Red 5, 48: 1, 48: 3, 53: 1, 57: 1, 81: 4, 122, 139, 144, 149, 150, 166, 177, 178, 222, 238, 269, C.I. I. Pigment Orange 31 and 43, C.I. I. Pigment yellow 14, 17, 74, 93, 94, 138, 155, 156, 158, 180, 185, C.I. I. Pigment green 7, C.I. I. Pigment Blue 15: 3, 60, and the like.
The colorant for obtaining the toner of each color can be used singly or in combination of two or more for each color. The content of the colorant is preferably 1 to 10% by mass in the toner base particles, and more preferably in the range of 2 to 8% by mass.

<Charge control agent>
The content ratio of the charge control agent is usually 0.1 to 10 parts by mass, preferably 0.5 to 5 parts by mass with respect to 100 parts by mass of the finally obtained binder resin.

(External additive particles)
The toner according to the present invention may include external additive particles in addition to the toner base particles. As the external additive particles, conventionally known external additive particles can be used. Examples of such external additive particles include inorganic oxide fine particles composed of silica fine particles, alumina fine particles, titania fine particles, inorganic stearic acid compound fine particles such as aluminum stearate fine particles and zinc stearate fine particles, or titanic acid. Examples thereof include fine particles of inorganic titanate compounds such as strontium and zinc titanate. These can be used alone or in combination of two or more. These inorganic fine particles are preferably subjected to a gloss treatment with a silane coupling agent, a titanium coupling agent, a higher fatty acid, a silicone oil or the like in order to improve heat-resistant storage stability and environmental stability.

(Toner glass transition point)
The glass transition point (Tg) of the toner according to the present invention is preferably in the range of 25 to 65 ° C., more preferably in the range of 35 to 55 ° C. When the glass transition point of the toner according to the present invention is in the above range, sufficient low-temperature fixing property and heat-resistant storage property can be obtained at the same time. The glass transition point of the toner is measured in the same manner as the amorphous resin except that the toner is used as a measurement sample.

(Toner particle size)
The average particle size of the toner according to the present invention is, for example, preferably 3 to 8 μm, more preferably 5 to 8 μm in terms of volume-based median diameter. This average particle diameter can be controlled by the concentration of the coagulant used in the production, the amount of the organic solvent added, the fusing time, the composition of the binder resin (binder resin), and the like. When the volume-based median diameter is in the above range, a very small dot image of 1200 dpi level can be faithfully reproduced. The volume-based median diameter of the toner is measured and calculated using a measuring device in which a computer system equipped with data processing software “Software V3.51” is connected to “Multisizer 3” (manufactured by Beckman Coulter). It is.

  Specifically, 0.02 g of a measurement sample (toner) was added to 20 mL of a surfactant solution (for example, a surfactant obtained by diluting a neutral detergent containing a surfactant component 10 times with pure water for the purpose of dispersing toner particles). The solution is added to the solution and allowed to acclimate. Then, ultrasonic dispersion is performed for 1 minute to prepare a toner dispersion, and this toner dispersion is placed in a beaker containing “ISOTON II” (Beckman Coulter) in a sample stand. Then, inject with a pipette until the displayed concentration of the measuring device is 8%. Here, a reproducible measurement value can be obtained by setting the concentration range. In the measuring apparatus, the measurement particle count number is 25000, the aperture diameter is 100 μm, and the frequency value is calculated by dividing the range of 2 to 60 μm, which is the measurement range, into 256 parts. % Particle diameter is defined as the volume-based median diameter.

(Average circularity of toner)
In the toner according to the present invention, the individual toner particles constituting the toner preferably have an average circularity of 0.930 to 1.000 from the viewpoint of stability of charging characteristics and low-temperature fixability. More preferably, it is in the range of 950 to 0.995. When the average circularity is within the above range, the individual toner particles are less likely to be crushed, the contamination of the frictional charge imparting member is suppressed, the toner chargeability is stabilized, and the image quality of the formed image is high. It will be a thing. The average circularity of the toner is a value measured using “FPIA-2100” (manufactured by Sysmex). Specifically, the measurement sample (toner) was blended with an aqueous solution containing a surfactant, dispersed by performing ultrasonic dispersion for 1 minute, and then subjected to measurement conditions HPF by “FPIA-2100” (manufactured by Sysmex). In the (high magnification imaging) mode, photographing is performed at an appropriate density with an HPF detection number of 3000 to 10000, the circularity is calculated according to the following formula for each toner particle, the circularity of each toner particle is added, and all toners are added. It is a value calculated by dividing by the number of particles. If the number of HPF detections is in the above range, reproducibility can be obtained.
Circularity = (perimeter of a circle having the same projection area as the particle image) / (perimeter of the particle projection image)

<Toner production method>
<Method for producing toner base particles>
The toner base particles according to the present invention can be produced, for example, by an emulsion aggregation method. The production method for producing the toner base particles according to the present invention by the emulsion aggregation method includes, for example, the dispersion liquid (a) containing the amorphous resin fine particles and the dispersion liquid (b) containing the crystalline polyester resin fine particles in the aqueous medium. And preparing a mixed dispersion, and heating the mixed dispersion to agglomerate the amorphous resin fine particles and the crystalline polyester resin fine particles to form toner base particles. It is a waste.

Here, the “aqueous medium” refers to a medium containing at least 50% by mass of water, and examples of components other than water include organic solvents that dissolve in water. For example, methanol, ethanol, isopropanol, butanol, acetone, methyl ethyl ketone, dimethylformamide, methyl cellosolve, tetrahydrofuran and the like can be mentioned. Among these, it is preferable to use an organic organic solvent such as methanol, ethanol, isopropanol, and butanol, which is an organic solvent that does not dissolve the resin. Preferably, only water is used as the aqueous medium.
The said manufacturing method can be comprised as what includes each following process, for example. Here, the following examples described the case where the amorphous resin fine particles contain a release agent, the crystalline polyester resin fine particles contain, and the toner base particles contain a colorant. However, the technical scope of the present invention is not limited to these forms.

(1) preparing a dispersion liquid (a) containing amorphous resin fine particles containing a release agent, a preparation process of the dispersion liquid (a),
(2) Dispersing the crystalline polyester resin in an organic solvent, emulsifying and dispersing it in an aqueous dispersion medium, and removing the organic solvent to prepare a dispersion (b) containing crystalline polyester resin fine particles. Preparation process)
(3) A step of preparing a mixed dispersion, wherein the dispersion (a) prepared in (1) and the dispersion (b) prepared in (2) are added to an aqueous medium to prepare a mixed dispersion,
(4) Aggregated particle forming step for forming toner base particles by aggregating the amorphous resin fine particles and the crystalline resin fine particles by heating the mixed dispersion prepared in (3) above;
(5) A maturing step of aging the aggregated particles formed in (4) above with heat energy to control the shape and obtaining toner base particles,
(6) a cooling step for cooling the dispersion of toner base particles;
(7) A filtration / washing step of filtering the toner base particles from the aqueous medium and removing the surfactant from the toner base particles.
(8) A drying step of drying the washed toner base particles.
As described above, the toner base particles according to the present invention include those composed of the steps (5) to (8) that can be added to the essential steps (1) to (4) as necessary. it can.

In carrying out the above-described steps, conventionally known knowledge can be referred to as appropriate. For example, the dispersion liquid (a) containing the amorphous resin fine particles and the dispersion liquid (b) containing the crystalline resin fine particles are prepared using various emulsification methods such as a method of emulsifying by mechanical shearing force. However, it is preferable to prepare using a method called a phase inversion emulsification method. In particular, when the dispersion (b) is prepared by a phase inversion emulsification method, oil droplets can be uniformly dispersed by changing the stability of the carboxy group of the polyester, as in the mechanical emulsification method. It is excellent in that it is not dispersed by shear force.
In the “phase inversion emulsification method”, a resin is dissolved in an organic solvent to obtain a resin solution, a neutralization step in which a neutralizer is added to the resin solution, and the neutralized resin solution is dispersed in an aqueous system. By passing through an emulsification step of emulsifying and dispersing in a medium to obtain a resin emulsion, and a desolvation step of removing the organic solvent from the resin emulsion, a dispersion of resin fine particles is obtained. The particle size of the resin fine particles in the dispersion can be controlled by changing the amount of neutralizing agent added.

  Further, the toner base particles having a core-shell structure can be obtained by using the toner base particles as a core and providing a shell layer on the surface thereof. By adopting a core-shell structure, heat-resistant storage properties and low-temperature fixability can be further improved. To produce toner base particles having a core-shell structure, for example, in the above-described production method, after the aggregated particle forming step (4), the following steps: (4 ′) toner base particles prepared in (4) above Is used as a core particle, and a shell dispersion (c) containing amorphous resin fine particles is added to the mixed dispersion to form a shell on the surface of the core particle, and then the above (5) The subsequent steps may be performed.

<Method for producing toner particles>
(External additive addition process)
The external additive adding step is a step of preparing toner particles by adding and mixing the external additive particles to the dried toner base particles. Examples of the method for adding the external additive include a dry method in which the external additive is added in powder form to the dried toner base particles. Examples of the mixing device include mechanical mixing devices such as a Henschel mixer and a coffee mill. It is done.

<Developer for developing electrostatic image>
The toner according to the present invention can be used as a magnetic or non-magnetic one-component developer, but may be mixed with a carrier and used as a two-component developer. When the toner is used as a two-component developer, the carrier uses magnetic particles made of a conventionally known material such as a metal such as iron, ferrite, or magnetite, or an alloy of such a metal with a metal such as aluminum or lead. In particular, ferrite particles are preferred. Further, as the carrier, a coated carrier in which the surface of magnetic particles is coated with a coating agent such as a resin, a dispersion type carrier in which a magnetic fine powder is dispersed in a binder resin, or the like may be used.
The volume-based median diameter of the carrier is preferably 20 to 100 μm, more preferably 25 to 80 μm. The volume-based median diameter of the carrier can be typically measured by a laser diffraction particle size distribution measuring apparatus “HELOS” (manufactured by SYMPATEC) equipped with a wet disperser.

  In the following examples, unless otherwise specified, “parts” and “%” mean “parts by mass” and “% by mass”, respectively, and each operation is performed at room temperature (25 ° C.). In addition, this invention is not limited to an Example.

<Production of toner>
(Synthesis of crystalline polyester (1))
A 5 L reaction vessel equipped with a stirrer, a temperature sensor, a cooling tube and a nitrogen introducing device was charged with 281 parts by mass of tetradecanedioic acid and 206 parts by mass of 1,6-hexanediol, and the system was stirred for 1 hour. The internal temperature was raised to 190 ° C. After confirming that the mixture was uniformly stirred, Ti (OBu) ₄ as a catalyst was added in an amount of 0.003% by mass with respect to 100% by mass of tetradecanedioic acid. Then, while distilling off the water produced, the internal temperature is raised from 190 ° C. to 240 ° C. over 6 hours, and polymerization is carried out by continuing the dehydration condensation reaction over 6 hours under the condition of 240 ° C. As a result, a crystalline polyester resin (1) was obtained. The number average molecular weight (Mn) was 4400.

(Synthesis of Styrene Acrylic Bonded Hybrid Crystalline Polyester (1))
A raw material monomer and a radical polymerization initiator of a styrene-acrylic resin unit having the following composition containing both reactive monomers were placed in a dropping funnel.
Styrene 34 parts by mass n-butyl acrylate 12 parts by mass Acrylic acid 2 parts by mass Polymerization initiator (di-t-butyl peroxide) 7 parts by mass In addition, a raw material monomer of the following crystalline polyester resin unit is replaced with a nitrogen inlet tube, dehydration It put into the 4 necked flask equipped with the pipe | tube, the stirrer, and the thermocouple, and it heated and dissolved at 170 degreeC.
Tetradecanedioic acid 271 parts by mass 1,6-hexanediol 118 parts by mass

Next, while stirring the contents of the flask, the raw material monomer of the styrene-acrylic resin unit was dropped over 90 minutes, and after aging for 60 minutes, unreacted styrene-acrylic resin unit under reduced pressure (8 kPa). The raw material monomer was removed. The amount of monomer removed at this time was very small with respect to the raw material monomer ratio of the resin.
Thereafter, 0.8 part by mass of Ti (OBu) ₄ was added as an esterification catalyst, the temperature was raised to 235 ° C., and the reaction was performed for 5 hours under normal pressure (101.3 kPa) and further for 1 hour under reduced pressure (8 kPa). went.

  Next, after cooling to 200 ° C., a hybrid crystalline polyester resin (1) was obtained by reacting under reduced pressure (20 kPa) for 1 hour. The content (HB ratio) of styrene-acrylic resin units other than CPEs with respect to 100% by mass of the total amount of the hybrid crystalline polyester resin (1) is 10% by mass. Alternatively, the number average molecular weight (Mn) of the hybrid crystalline polyester resin (1) was 6400.

(Synthesis of Styrene-Acrylic Bond Hybrid Crystalline Polyester (2))
A hybrid crystalline polyester resin (2) was obtained in the same manner as the hybrid crystalline polyester (1) except that the raw material monomer of the crystalline polyester resin unit having the composition shown below was used. The HB ratio was 10% by mass, and the number average molecular weight (Mn) was 7500.
Dodecanedioic acid 241.5 parts by mass Ethylene glycol 62.1 parts by mass

(Synthesis of non-crystalline polyester (1))
In a reaction vessel equipped with a cooling tube, a stirrer and a nitrogen introduction tube, 316 parts by mass of bisphenol A propylene oxide 2 mol adduct, 80 parts by mass of terephthalic acid, 34 parts by mass of fumaric acid and titanium tetraisopropoxide as a polycondensation catalyst 2 parts by mass were divided into 10 times and reacted at 200 ° C. for 10 hours while distilling off the water generated under a nitrogen stream.
Subsequently, it was made to react under reduced pressure of 13.3 kPa (100 mmHg), and it took out when the softening point became 104 degreeC, and obtained amorphous polyester resin (1).

(Preparation of dispersion of crystalline polyester (1), hybrid crystalline polyester (1) to (2), amorphous polyester (1))
100 parts by mass of the crystalline polyester resin (1) was dissolved in 400 parts by mass of ethyl acetate. Subsequently, 25 mass parts of 5.0 mass% sodium hydroxide aqueous solution was added, and the resin solution was formed. This resin solution was put into a container having a stirrer, and 400 parts by mass of a 0.26 mass% sodium lauryl sulfate aqueous solution was dropped and mixed over 30 minutes while stirring the resin solution. During the dropwise addition of the sodium lauryl sulfate aqueous solution, the liquid in the reaction vessel became cloudy. Further, the whole amount of the sodium lauryl sulfate aqueous solution was dropped to prepare an emulsion in which resin solution particles having a solid content of 20% were uniformly dispersed.
For other resins, an emulsion dispersion having a solid content of 20% was obtained in the same manner.

(Preparation of Wax-Containing Styrene-Acrylic Resin Particle Dispersion (1) for Core)
[First stage polymerization]
In a reaction vessel equipped with a stirrer, a temperature sensor, a temperature controller, a cooling pipe, and a nitrogen introduction device, 2.0 parts by mass of an anionic surfactant “sodium lauryl sulfate” was dissolved in 2900 parts by mass of ion-exchanged water in advance. An anionic surfactant solution was charged, and the internal temperature was raised to 80 ° C. while stirring at a stirring speed of 230 rpm under a nitrogen stream. To this surfactant solution, 9.0 parts by mass of a polymerization initiator “potassium persulfate: KPS” was added and the internal temperature was adjusted to 78 ° C.
Styrene 540 parts by weight n-butyl acrylate 270 parts by weight Methacrylic acid 65 parts by weight n-octyl mercaptan 17 parts by weight of solution (1) was added dropwise over 3 hours, and after completion of the addition, heating and stirring at 78 ° C. for 1 hour Thus, polymerization (first stage polymerization) was performed to prepare “a dispersion of resin particles [a1]”.

[Second stage polymerization: formation of intermediate layer]
In a flask equipped with a stirrer,
Styrene 94 parts by weight n-butyl acrylate 60 parts by weight Methacrylic acid 11 parts by weight n-octyl mercaptan 5 parts by weight Paraffin wax (melting point: 73 ° C.) 51 parts by weight as a release agent was added, “Monomer solution [2]” was prepared by heating to 85 ° C. and dissolving.

  Here, a surfactant solution in which 2 parts by mass of the anionic surfactant “sodium lauryl sulfate” was dissolved in 1100 parts by mass of ion-exchanged water was heated to 90 ° C. After adding 28 parts by mass of “dispersion of resin particles [a1]” in terms of solid content of resin particles [a1] to this surfactant solution, mechanical disperser “Clairemix” (M The above-mentioned monomer solution [2] was mixed and dispersed for 4 hours by Technic Co., Ltd. to prepare a dispersion containing emulsified particles having a dispersed particle diameter of 350 nm.

  An initiator aqueous solution in which 2.5 parts by mass of a polymerization initiator “KPS” was dissolved in 110 parts by mass of ion-exchanged water was added to the dispersion, and the system was polymerized by heating and stirring at 90 ° C. for 2 hours. (Second-stage polymerization) was performed to prepare “dispersion of resin particles [a2]”.

[Third-stage polymerization: formation of outer layer]
An initiator aqueous 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 above “dispersion of resin particles [a2]”, and the temperature is 80 ° C. ,
Styrene 230 mass parts n-butyl acrylate 100 mass parts n-octyl mercaptan Solution (3) which consists of 5.2 mass parts was dripped over 1 hour. After completion of the dropwise addition, polymerization (third stage polymerization) was carried out by heating and stirring for 3 hours. Then, it cooled to 28 degreeC and prepared "the wax-containing styrene-acryl resin particle dispersion liquid (1) for cores" which dispersed the resin particles for cores (1) in the anionic surfactant solution. The wax content is 9.8% with respect to 100 mass of the resin.

(Preparation of wax-containing core styrene-acrylic resin particle dispersions (2) to (3))
The styrene-acrylic resin particle dispersion liquid (2) for the wax-containing core is a styrene-acrylic resin particle dispersion liquid (1) for the wax-containing core except that the wax content is adjusted to 11.0% with respect to 100 mass of the resin. Adjusted in the same manner.
The styrene-acrylic resin particle dispersion liquid (3) for the wax-containing core is used except that the wax content is adjusted to 13.5% with respect to 100 mass of the resin. Adjusted in the same manner.

(Preparation of wax-containing amorphous polyester resin (1) particle dispersion)
After adding 100 parts by mass of amorphous polyester resin (1) to 400 parts by mass of ethyl acetate (manufactured by Kanto Chemical Co., Inc.) with stirring, 9.8 parts by mass of paraffin wax (melting point: 73 ° C.) and wax 5 parts by mass of a dispersion aid (manufactured by NOF Corporation: BP-70R sorbitan monobehenate) was added and dissolved by heating.

Next, 638 parts by mass of a sodium lauryl sulfate solution having a concentration of 0.26% by mass prepared in advance was mixed, and ultrasonic dispersion was performed with an ultrasonic homogenizer “US-150T” (manufactured by Nippon Seiki Seisakusho Co., Ltd.) at 300 μA for 30 minutes. did.
Then, using a diaphragm vacuum pump V-700 (manufactured by Nihon Büch) while being heated to 50 ° C., ethyl acetate was completely removed while stirring for 5 hours under reduced pressure, and the solid content was 20 parts by mass. A wax-containing amorphous polyester resin (1) particle dispersion ”was obtained.

(Preparation of aqueous dispersion of colorant fine particles (Cy1))
90 parts by mass of sodium lauryl sulfate was added to 1600 parts by mass of ion-exchanged water. While stirring this solution, 420 parts by mass of copper phthalocyanine (CI Pigment Blue 15: 3) is gradually added, and then dispersed using a stirrer “CLEARMIX” (manufactured by M Technique). As a result, an aqueous dispersion (Cy1) of colorant fine particles was prepared. The volume-based median diameter of the colorant fine particles contained in the dispersion (Cy1) was 130 nm.

(Production of Toner (1))
Into a reaction vessel equipped with a stirrer, a temperature sensor and a cooling tube, 170 parts by mass (in terms of solid content) of styrene-acrylic resin particle dispersion (1) for wax-containing core and 2000 parts by mass of ion-exchanged water were added. The pH of the solution was adjusted to 10 by adding 5 mol / liter aqueous sodium hydroxide solution.
Thereafter, 10 parts by mass (based on solid content) of an aqueous dispersion (Cy1) of colorant fine particles was added, and then an aqueous solution in which 60 parts by mass of magnesium chloride was dissolved in 60 parts by mass of ion-exchanged water was stirred at 30 ° C. Added over 10 minutes. Next, the mixture is allowed to stand for 3 minutes, and 30 parts by mass (in terms of solid content) of an aqueous dispersion of crystalline polyester resin fine particles (1) is added over 10 minutes, and then the temperature is raised to 82 ° C. over 60 minutes. The particle growth reaction was continued while being held.

  In this state, the particle size of the associated particles was measured with “Coulter Multisizer 3” (manufactured by Beckman Coulter). When the volume-based median diameter reached 6.0 μm, 190 parts by mass of sodium chloride was ion-exchanged. An aqueous solution dissolved in 760 parts by mass of water is added to stop particle growth, and the mixture is heated and stirred at a temperature of 74 ° C. to advance the fusion of the particles and to measure the average circularity of the toner “FPIA-2100” ( When the average circularity reached 0.957, the mixture was cooled to 30 ° C. at a cooling rate of 2.5 ° C./min.

Next, the operation of solid-liquid separation and re-dispersion of the dehydrated toner cake in ion-exchanged water and solid-liquid separation is washed three times, and then dried at 40 ° C. for 24 hours to obtain a toner base (1). It was.
To 100 parts by mass of the obtained toner particles (1X), 0.6 part by mass of hydrophobic silica (number average primary particle size = 12 nm, degree of hydrophobicity = 68) and hydrophobic titanium oxide (number average primary particle size = 20 nm, Hydrophobic degree = 63) 1.0 part by mass was added and mixed with a “Henschel mixer” (manufactured by Nihon Coke Kogyo Co., Ltd.) at a rotating blade peripheral speed of 35 mm / sec at 32 ° C. for 20 minutes. A toner (1) was produced by applying an external additive treatment to remove coarse particles using a sieve with openings.

(Production of Toner (2))
Toner (1) except that the crystalline polyester resin of toner (1) is changed to an aqueous dispersion (1) of hybrid crystalline polyester resin fine particles and the mass used is changed to 20 parts by mass (in terms of solid content). A toner (2) was obtained in the same manner.

(Production of Toner (3))
Similar to toner (1), except that the styrene-acrylic resin particle dispersion (1) for the wax-containing core of toner (1) is changed to a dispersion (1) of wax-containing amorphous polyester resin (1) particles. The toner (3) was obtained.

(Production of Toner (4))
The styrene-acrylic resin particle dispersion (1) for the wax-containing core of the toner (1) is changed to a styrene-acrylic resin particle dispersion (2) for the wax-containing core, and 10 parts by mass of the amorphous polyester (1) dispersion (Solid content conversion) was added dropwise over 10 minutes when the toner became 6 μm. Other than that was produced like toner (1).

(Production of Toner (5))
The styrene-acrylic resin particle dispersion (1) for the wax-containing core of the toner (1) is changed to the styrene-acrylic resin particle dispersion (2) for the wax-containing core, and the crystalline polyester (1) dispersion of the toner (1) is changed. It was produced in the same manner as the toner (1) except that the liquid was changed to 30 parts by mass (in terms of solid content).

(Production of Toner (6))
A toner was prepared in the same manner as in the toner (1) except that the crystalline polyester (1) dispersion of the toner (1) was changed to 3 parts by mass (in terms of solid content) of the hybrid crystalline polyester (1) dispersion.

(Production of Toner (7))
The styrene-acrylic resin particle dispersion (1) for the wax-containing core of the toner (1) is changed to the styrene-acrylic resin particle dispersion (3) for the wax-containing core, and the crystalline polyester (1) dispersion of the toner (1) is changed. It was prepared in the same manner as the toner (1) except that the liquid was changed to 35 parts by mass (in terms of solid content).

(Production of Toner (8))
The toner (1) was prepared in the same manner as the toner (1) except that the crystalline polyester (1) dispersion was not added.

(Production of Toner (9))
The toner (4) was prepared in the same manner as the toner (4) except that the crystalline polyester (1) dispersion was not added.

(Production of Toner (10))
A toner was prepared in the same manner as in the toner (7) except that the crystalline polyester (2) dispersion of the toner (7) was changed to 40 parts by mass of the hybrid polyester resin (2) dispersion.

(Preparation of developers 1 to 10 for developing electrostatic image)
100 parts by mass of ferrite core and 5 parts by mass of copolymer resin particles of cyclohexyl methacrylate / methyl methacrylate (copolymerization ratio 5/5) are put into a high-speed mixer equipped with stirring blades and stirred and mixed at 120 ° C. for 30 minutes. A resin coat layer was formed on the surface of the ferrite core by the action of mechanical impact force to obtain a carrier having a volume-based median diameter of 35 μm.
The volume-based median diameter of the carrier was measured with a laser diffraction particle size distribution measuring apparatus “HELOS” (manufactured by Sympathic) equipped with a wet disperser. Toners 1 to 10 are added to the carrier so that the toner concentration is 6% by mass, and the toner is introduced into a micro-type V-type mixer (Tsutsui Riken Kikai Co., Ltd.), mixed at a rotational speed of 45 rpm for 30 minutes, and developed. 1 to 10 were produced (Table 1).

(Volume resistivity)
About the produced electrostatic charge image developing developers 1 to 10, 2 g of toner previously conditioned overnight at a temperature of 20 ° C. and a humidity of 25% was molded for 45 seconds with a thickness of 45 mm and a pressure of 150 kN for 10 seconds. Volume resistivity was measured using a digital ultra-high resistance measuring instrument 5450 (conditions: temperature 70 ° C., applied voltage 500 V, 3 minutes value).

[Evaluation method]

(Adhesion force evaluation)
Using “bizhub PRESS C1070 (manufactured by Konica Minolta)”, 100 sheets of solid images (toner adhesion amount: 10.5 g / m ² ) were output on both sides (paper type: OK top coat paper (manufactured by Oji Paper Co., Ltd.)) A3 157 g / m ² ). The formed solid image was stacked. From the stacked sheets S, 11 out of 70 to 80 sheets from the top are extracted and placed on a flat table, and a tape T is applied to the tip of the short side of the top sheet S and slowly in the horizontal direction H. I slipped.
At this time, the sheet lower than the second sheet from the top is fixed to the table so as not to move. The force required to slide the paper was measured with a spring alone. This measurement was repeated ten times in order from the top, and the average value of the force indicated by the spring was used as the sticking force (FIG. 3). When the sticking force was 1.5 N or less, it was set to a practical level.

◎: 0 or more and less than 1.0N ○: 1.0N or more and 1.5N or less ×: Greater than 1.5N

(Evaluation of fixing separation)
Using “bizhub PRESS C1070 (manufactured by Konica Minolta Co., Ltd.)”, the margin of the solid image (toner adhesion amount: 8.0 g / m ² , paper: mondi90) at normal temperature and normal humidity (temperature 20 ° C., relative humidity 55%) The minimum amount of blank space that can be passed continuously for five sheets was evaluated.
The smaller the margin amount, the better the separation performance.
(Criteria)
◎: Margin less than 4 mm ○: Margin 4 or more and less than 7 mm Δ: Margin 7 or more and less than 10 mm ×: Margin 10 mm or more

(Measurement of fogging)
In the fog measurement, the white density of the image support is measured at 20 points of A4 size, and the average value is set as the white paper density. Next, the white background portion of the 4000th image at a printing rate of 5% is similarly 20 The absolute image density was measured and averaged, and the value obtained by subtracting the blank paper density from this average density was evaluated as the fog density. If the fog density was 0.01 or less, the fog was accepted. Density measurement was performed using a reflection densitometer “RD-918” (manufactured by Macbeth).
A: Less than 0.003 B: 0.003 or more and less than 0.006 B: 0.006 or more and 0.010 or less X: A value greater than 0.010

(Comprehensive judgment)
Comprehensive determination was determined as follows from the comprehensive points of each evaluation item, and is shown in Table 2.
◎: Number of ◎ in each evaluation item is 2 or more ○: Number of ◎ in each evaluation item is 1 ×: Number of x in each evaluation item is 1 or more

DESCRIPTION OF SYMBOLS 8 Fixing device 10Y, 10M, 10C, 10K Image forming part 21 Paper feed part 23 Registration roller 24 Paper discharge roller 25 Paper discharge tray 81 Fixing belt 82 Heating roller 83 Fixing roller 84 Pressure roller 85 Pressure roller holding plate 201 Automatic document Feeder 202 Document image scanning exposure apparatus F Suction fan GH Image forming apparatus main body N Nip part P, S Paper X Electrophotographic image forming apparatus YS Image reading apparatus d Document T Tape H Horizontal direction

Claims (6)

Electrophotographic image formation using means for spraying air to the paper and separating the paper from the heating / pressurizing unit in the step of fixing the toner image by heating and pressurizing the paper carrying the electrostatic image developing toner. A method,
The electrostatic charge image developing toner contains at least a colorant, a release agent, and a non-crystalline resin and a crystalline polyester resin as a binder resin, and the volume resistivity of the electrostatic charge image developing toner at 70 ° C. Is in the range of 1 × 10 ^{13 to} 5 × 10 ¹⁶ Ω · cm.   2. The electrophotographic image forming method according to claim 1, wherein the amorphous resin contains an amorphous polyester resin.   The electrophotographic image forming method according to claim 2, wherein the amorphous resin further contains a styrene-acrylic resin.   The said crystalline polyester resin is contained within the range of 3-30 mass% with respect to the total amount of the said binder resin, It is any one of Claim 1 to 3 characterized by the above-mentioned. Electrophotographic image forming method.   5. The electrophotographic image forming method according to claim 1, wherein the crystalline polyester resin contains a hybrid polyester resin formed by bonding with a different resin. 6.   An electrophotographic image forming apparatus comprising: means for forming an image by the electrophotographic image forming method according to any one of claims 1 to 5.

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