JP6520589B2 - Electrophotographic image forming method and electrophotographic image forming apparatus - Google Patents

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 and the like in which fixing is performed by a fixing device with air separation using a toner for electrostatic charge image development containing a crystalline polyester resin.

  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 advanced. In order to lower the fixing temperature of the toner, it is necessary to lower the melting temperature and the melt viscosity of the binder resin constituting the toner. However, since the sheet is heated and melted when passing through the fixing nip portion, the sheet may not be wound around the fixing roller or the surface of the fixing belt and separated due to the adhesive force of the toner, which may cause a paper jam. Therefore, in order to prevent the sheet from being wound in the fixing device, a technique relating to an air separation mechanism is proposed in which air is jetted from the discharge port to the sheet discharged from the nip portion to separate the sheet from the fixing roller and the fixing belt. (See, for example, Patent Document 1).

Paper discharged by low-temperature fixing and air jet tends to be low temperature, and when printing a double-printed image with high printing rate in such a process, discharge of the charge stored in the toner does not occur sufficiently . As a result, it was found that a phenomenon occurs in which the images are charged, and the images stick to each other, and further, the stacked sheets having the images stick.
Therefore, there has been a demand for a technology that does not cause sticking between images even in a fixing device process equipped with an air separation mechanism.

For example, Patent Document 2 proposes that an image forming apparatus is provided with a humidifying device to humidify the sheet to suppress curling and waviness of the sheet, but the effect is satisfactory with regard to image sticking. Since it has not been obtained, improvement in performance is desired.
In addition, although a document that defines the volume resistivity of toner is reported (for example, see Patent Documents 3 and 4), all are defined in terms of the stability of the chargeability, and for image sticking. The effect of was not obtained.

JP, 2011-242429, A Unexamined-Japanese-Patent No. 2007-286151 JP 2014-121191 A JP, 2005-266546, A

  The present invention has been made in view of the above problems and circumstances, and an object of the present invention is to provide an electrophotographic image forming method which achieves both excellent fixing separation, suppression of sticking of stacked sheets, and low fog. It is.

As a result of examining the cause of the above problems and the like in order to solve the above-mentioned problems, the inventor of the present invention carries an electrophotographic image forming method of the present invention on which an electrostatic charge image developing toner (hereinafter simply referred to as "toner") is carried. An electrophotographic image forming method using means for spraying air onto the sheet to separate the sheet from the heating / pressurizing section in the step of fixing the toner image by heating / pressurizing the sheet; The toner for image development contains at least a colorant, a release agent, and an amorphous resin and a crystalline polyester resin as a binder resin, and the volume resistivity of the toner for electrostatic charge image development at 70 ° C. is predetermined. The present invention has been found to be compatible with the excellent fixing separation property and the suppression of sticking of stacked sheets.
That is, the above-mentioned subject of the present invention is solved by the following means.

1. Electrophotographic image formation using a means for separating the sheet from the heating / pressurizing section by jetting air onto the sheet in the step of heating / pressurizing the sheet carrying the electrostatic image developing toner to fix the toner image Method,
The toner for electrostatic charge image development contains toner base particles containing at least a colorant, a release agent, and a styrene-acrylic resin and a crystalline polyester resin as a binder resin, and the electrostatic charge image development at 70 ° C. An electrophotographic image forming method characterized in that a volume resistivity of the toner for use is in a range of 1 × 10 ^{13 to} 5 × 10 ¹⁶ Ω · cm.

2. The electrophotographic image forming method according to claim 1 , further comprising an amorphous polyester resin as the binder resin .

3 . 3. The electrophotographic image forming method according to item 1 or 2, wherein the crystalline polyester resin is contained in a range of 3 to 30% by mass with respect to the total amount of the binder resin.

4 . The electrophotographic image forming method according to any one of Items 1 to 3, wherein the crystalline polyester resin contains a hybrid polyester resin formed by bonding with different resins.
5. The electrophotographic image forming method according to any one of claims 1 to 4, wherein the toner base particles have a core-shell structure.

  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.

  According to the above-described means of the present invention, it is possible to provide an electrophotographic image forming method which achieves both excellent fixing and separating properties, suppression of sticking of stacked sheets and less fogging.

The mechanism for expressing the effect of the present invention or the mechanism of action is not clear but is presumed as follows.
The mechanism for preventing the image from being wound around the fixing roller by injecting air to the sheet discharged from the fixing nip portion in order to improve the fixing separation property is also provided with a conventional image forming apparatus. When the image is fixed by the fixing device with air separation, the image is rapidly cooled by the air, so that the charge remains on the image even after the fixing. Then, in the case of double-sided printing, the toner layer on the first side bears a charge at the time of secondary transfer, that is, a reverse charge to the toner. If paper (image) is loaded in this state, the charges on the image on the second side of the n-th sheet and the first side of the n + 1st sheet are attracted to each other, and the images are electrostatically stuck to each other. Is worse.

In addition, when the image is cooled by the decrease of the fixing temperature and the air injection, the amount of charge remaining on the image is further increased due to the volume resistivity of the toner (image) becoming high as the image temperature decreases. Paper sticking tended to deteriorate.
Since the crystalline polyester resin generally tends to have a low volume resistivity even at normal 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 In the high temperature region, the difference becomes more noticeable. The definition of volume resistivity at 70 ° C. assumes the image temperature which is higher than the glass transition temperature 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 decreases and the fogging performance decreases. On the other hand, if the volume resistivity is more than 5 × 10 ¹⁶ Ω · cm, the adhesion between the papers becomes strong, and the paper removability becomes worse.
Therefore, by forming an electrophotographic image using toner having a volume resistivity within a predetermined range used in the present invention, the sticking property is suppressed while preventing winding by air injection, and a good image with less fogging is obtained. It is assumed that you can get

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

In the electrophotographic image forming method of the present invention, air is jetted onto the sheet in the step of fixing the toner image by heating and pressing the sheet carrying the electrostatic image developing toner, and the heating and pressing unit Wherein the toner for developing an electrostatic charge image comprises at least a colorant, a release agent, and a styrene-acrylic resin and a crystalline polyester resin as a binder resin . The toner of the present invention is characterized in that it contains toner base particles and the volume resistivity of the toner for electrostatic charge image development 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 following embodiments.

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

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.
Further, the crystalline polyester resin is preferable in that it contains a hybrid polyester resin formed by bonding different types of resins, so that it becomes easy to conform to the non-crystalline resin and the molecular chain of the crystalline resin is easily arranged.

  Further, 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 the effects of the present invention.

  BEST MODE FOR CARRYING OUT THE 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 uses the numerical value described before and after that in the meaning included as a lower limit and an upper limit.

[Overview of Electrophotographic Image Forming Method]
In the electrophotographic image forming method of the present invention, air is jetted onto the sheet in the step of fixing the toner image by heating and pressing the sheet carrying the electrostatic image developing toner, and the heating and pressing unit An electrophotographic image forming method using means for separating the toner, wherein the toner for developing an electrostatic charge image contains at least a colorant, a releasing agent, and a noncrystalline resin and a crystalline polyester resin as a binder resin, The volume resistivity of the toner for electrostatic charge image development at 70 ° C. is in the range of 1 × 10 ^{13 to} 5 × 10 ¹⁶ Ω · cm.
As a summary of a specific electrophotographic image forming method, a heating member for heating a sheet carrying a toner image and a nip portion for holding the sheet carrying a toner image are brought into contact with the sheet by contacting the heating member. A fixing device is used which has a heating member for fixing an image, and means for injecting air to the sheet discharged from the nip portion to separate the sheet from the heating member.
The details of the electrophotographic image forming apparatus, fixing device and toner used in the present invention will be described in order.

[Overview 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-like intermediate transfer belt 5, a sheet feeding and conveying unit, a fixing device 8, and the like.
An image reading apparatus YS including an automatic document feeder 201 and a document image scanning and exposing apparatus 202 is installed at 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 conveyed by the conveyance unit, and the optical system of the document image scanning and exposing device 202 scans and exposes an image of one side or both sides of the document d. It 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, 3K Sent to
In the image forming unit 10Y for forming a yellow (Y) color image, a charging unit 2Y, an exposure unit 3Y, a developing unit 4Y, and a cleaning unit 7Y are disposed 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 toners and carriers of small particle sizes of yellow (Y), magenta (M), cyan (C), and black (K). The toner is made of, for example, a pigment or a dye serving as a colorant, a release agent that helps the toner to be separated from the fixing belt 81 after fixing, and a binder resin that holds these.

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

[Summary of fixing device]
FIG. 2 is an enlarged sectional view of the fixing device 8.
The fixing device 8 is composed of a fixing frame 8F whose outer frame is composed of a plurality of frame members. Each member constituting the fixing device 8 is directly or indirectly supported by the fixing frame 8F. 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 direction in FIG. 2 and FIG. 2). .

The fixing belt 81, which is a heating member, is formed endlessly, and for example, PI (polyimide) having a thickness of 70 μm is used as a substrate, and a heat resistant silicone rubber having a thickness of 200 μm is used. The surface is coated with PFA (perfluoroalkoxy), which is a heat-resistant resin with a thickness of 30 μm.
The fixing belt 81 is stretched around the heating roller 82 and the fixing roller 83.
The heating roller 82 incorporates a halogen heater 82A for heating the fixing belt 81, and for example, a resin having a thickness of 4 mm and a cylindrical core metal 82B formed of aluminum or the like coated with PTFE of 30 μm thickness It is covered with a 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 correspond to different sheet widths, and the heat generation distributions different in the axial direction corresponding to different sheet widths of sheets. 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 the present embodiment, the pressure roller 84 corresponds to the pressure member in the present invention. The fixing roller 83 covers a solid cored bar 83A made of metal such as iron with a 20 mm thick heat resistant silicone rubber as an elastic layer 83B, and further with a 30 μm thick low friction and heat resistant resin It is coated with a certain PTFE coated resin layer 83C.

A temperature detection sensor SE for detecting the temperature of the fixing belt 81 without contacting the fixing belt 81 is installed around the heating roller 82. Based on the detection result of the temperature detection sensor SE, ON / OFF control of the halogen heater 82A is performed, 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 to shorten the temperature rising time immediately after the power is turned on to the image forming apparatus X, and is a cylinder made of aluminum or the like and having a thickness of 4 mm. The outer peripheral surface of the cored bar 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 There is. The outer diameter dimension is 90 mm. The pressing roller 84 is pressed against the fixing belt 81 and the fixing roller 83 by urging means (not shown).

In the above configuration, when the pressure roller 84 is rotated counterclockwise (x direction in FIG. 2) by the driving unit (not shown), the fixing belt 81, the heating roller 82, and the fixing roller 83 are clockwise (y direction in FIG. 2). To rotate).
The fixing belt 81 is heated by the halogen heater 82A via the heating roller 82 in contact, and the pressure roller 84 is also heated by the halogen heater 84A. Then, in the nip portion N formed between the fixing belt 81 wound around the fixing roller 83 and the pressure roller 84, the fed sheet is heated and pressed, and the toner image on the sheet is fixed. Ru.

[Overview of air separation mechanism]
In the fixing device 8, as a cooling unit, an air separation unit is provided which blows air on the sheet discharged from the nip portion N to separate the sheet from the fixing belt 81. The air separation unit is configured of a suction fan F, a first duct 121, and a second duct 131 shown in FIG.
The first duct 121 is formed of a stretchable flexible member, and the second duct 131 is formed of a metal such as iron. The end of the first duct 121 is fixed to the end of the second duct 131. Even if the second duct 131 is movable as described later, the first duct 121 is deformed and the opening 121b of the first duct 121 is deformed. And air does not leak from between the opening 131a of the second duct 131 and the opening 131a.

As shown in FIG. 2, the opening 121 a 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 131 b, which is the other opening of the second duct 131, is disposed near the nip N. The air sent from the suction fan F flows in the direction of the arrow shown in FIG. 2 in the first duct 121 and the second duct 131 and is discharged from the discharge port 131b, and the vicinity of the leading end of the sheet discharged from the nip N Be sprayed. Thus, air can enter between the sheet and the fixing belt 81, and the sheet can be properly separated from the fixing belt 81 to prevent the sheet from being wound. In addition, the sheet is separated from the fixing belt 81 by the air separation unit including the suction fan F, the first duct 121, and the second duct 131, so that the member such as the separation claw does not contact the surface of the fixing belt 81. Since the sheet can be separated, the surface of the fixing belt 81 is not damaged.
The sheet separated from the fixing belt 81 by the air separation unit is guided by the upper guide 211 and the lower guides 212 and 213, is sandwiched by the conveying rollers R1 and R2, and is a discharge roller positioned downstream of the fixing device 8 in the conveying direction. It is transported in the direction of 24 (see FIG. 1).

[Toner for electrostatic image development]
The toner for electrostatic image development according to the present invention contains at least a colorant, a releasing agent, and a non-crystalline resin and a crystalline polyester resin as a binder resin, and the toner for electrostatic image development at 70 ° C. The volume resistivity is characterized by being in the range of 1 × 10 ^{13 to} 5 × 10 ¹⁶ Ω · cm.
Details of 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". "Toner base particles" are referred to as "toner particles" by the addition of external additives. And "toner" shall mean an aggregate of "toner particles".

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

The glass transition temperature of the toner is preferably 40 to 70 ° C., and more preferably 45 to 65 ° C. When the temperature is lower than 40 ° C., the heat resistance is inferior, and when the temperature is higher than 70 ° C., the fixability is inferior.
Also, 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 reduced, and the fogging performance is reduced. On the other hand, if it is larger than 5 × 10 ¹⁶ Ω · cm, the adhesion between papers becomes strong, and the paper removability becomes worse. From the viewpoint of fogging, the volume resistivity at normal temperature is preferably in the range of 5 × 10 ^{15 to} 3 × 10 ¹⁸ Ω · cm.

Moreover, as for the volume resistivity of crystalline polyester to be used, it is desirable to exist in the range of 1 * 10 < ¹⁰ > -1 * 10 < ¹⁴ > ohm * cm.
In order to achieve the specified volume resistivity, it is better for the crystalline polyester to be uniformly dispersed in the toner. For this purpose, it is desirable that the dispersed particle size of the crystalline polyester be in the range of 100 to 300 nm, more preferably in the range of 150 to 250 nm. The crystalline polyester resin can be uniformly dispersed in the toner by controlling the dispersed particle size. Here, “disperse uniformly” means making the conductive path of the crystalline polyester impossible.

(Toner base particle)
The toner base particles used in the present invention contain an amorphous resin and a crystalline polyester resin as a binder resin (binder resin). In addition, the toner base particles may contain other toner components such as magnetic powder and charge control agent. In addition, it is preferable that the toner base particles used in the present invention be obtained by a wet manufacturing method (for example, an emulsion aggregation method) manufactured in an aqueous medium.

<Binder resin (noncrystalline 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 noncrystalline resin to the crystalline resin (noncrystalline resin / crystalline resin) is preferably in the range of 97/3 to 70/30, and more preferably 95/5 to 75/25. Within the scope of Defining the amount of crystalline polyester makes it easy to control the volume resistivity to a more preferable range.

[Non-crystalline resin]
The non-crystalline resin is not particularly limited, and non-crystalline resins conventionally known in the technical field may be used. Among them, the non-crystalline resin preferably contains a non-crystalline vinyl resin. When the non-crystalline resin contains a vinyl resin, a toner having excellent plasticity at the time of heat fixing can be provided.
Here, the "vinyl-based resin" is a resin obtained by polymerization using at least a vinyl-based monomer.

Specific examples of non-crystalline vinyl resins include acrylic resins and styrene-acrylic resins. Among them, as the non-crystalline vinyl-based resin, a styrene-acrylic resin formed using a styrene-based monomer and a (meth) acrylate-based 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 entire toner. More preferably, it is in the range of 60 to 80% by mass. By adjusting within the range, it becomes possible to control the volume resistivity of the toner.
As a vinyl-type monomer which forms non-crystalline vinyl-type resin, 1 type (s) or 2 or more types selected from the following can be used.

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

(2) (Meth) Acrylate Ester-Based Monomer As the (meth) acrylate-based monomer, methyl (meth) acrylate, ethyl (meth) acrylate, n-butyl (meth) acrylate, ( Isopropyl acrylate, isobutyl (meth) acrylate, t-butyl (meth) acrylate, n-octyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, stearyl (meth) acrylate, (meth) Examples thereof 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-Based Monomer Examples of the vinyl ether-based monomer include vinyl methyl ether and vinyl ethyl ether.

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

(6) N-Vinyl Based Monomer As the N-vinyl based monomer, N-vinylcarbazole, N-vinyl indole, N-vinyl pyrrolidone and the like can be mentioned.

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

Further, as the vinyl-based monomer, it is preferable to use, for example, a monomer having an ionic dissociative group such as a carboxy group, a sulfonic acid group or a phosphoric acid group. Specifically, the following may be mentioned.
Examples of the monomer having a carboxy group include acrylic acid, methacrylic acid, maleic acid, itaconic acid, cinnamic acid, fumaric acid, monoalkyl ester of maleic acid and monoalkyl ester of itaconic acid. Moreover, as a monomer which has a sulfonic acid group, styrene sulfonic acid, allyl sulfosuccinic acid, 2-acrylamido 2-methyl propane sulfonic acid etc. are mentioned. Furthermore, as a monomer having a phosphoric acid group, acid phosphoxoxyethyl methacrylate and the like can be mentioned.

  Furthermore, polyfunctional vinyls may be used as the vinyl-based monomer, and the non-crystalline vinyl-based resin may have a crosslinked structure. As polyfunctional vinyls, 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 Diacrylate etc. are mentioned.

Although the vinyl resin has been described in detail as a preferred embodiment of the non-crystalline resin, it is also preferable that the non-crystalline resin contains a non-crystalline polyester resin.
Also, in general, the volume resistivity is determined by the chemical structure and the thermal characteristics. The non-crystalline polyester resin has many hydroxy groups which tend to lower the volume resistivity, and the temperature difference from the glass transition point to the softening point is small, so that the molecular motion rapidly becomes active with temperature. Therefore, it has the property that resistance to heat is easily lowered.
Specifically, the hydroxyl value of the non-crystalline polyester resin is preferably in the range of 20 to 50 mg KOH / g, and the increase in volume resistivity can be suppressed by setting it to 20 mg KOH or more, and it is set to 50 mg KOH or less The water absorbency 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 the acetic acid bound to the acetylated compound contained in 1 g of resin etc. Etc. and calculated from the amount of neutralization obtained by titration with a potassium hydroxide solution whose titer is accurately confirmed. As a specific measuring method of a hydroxyl value, the method shown by JIS 0070-1992 is mentioned, for example.

The glass transition point (Tg) of the non-crystalline resin is preferably in the range of 40 to 70 ° C., and more preferably in the range of 45 to 65 ° C. When the glass transition temperature of the non-crystalline resin is in the above range, sufficient low temperature fixability and heat resistant storage stability can be obtained at the same time.
In addition, the glass transition point (Tg) of non-crystalline resin is a value measured using "diamond DSC" (made by Perkin-Elmer Co., Ltd.).

  As a measurement procedure, 3.0 mg of a measurement sample (noncrystalline resin) is enclosed in an aluminum pan and set in a holder. The reference used an empty aluminum pan. As measurement conditions, temperature control is performed at a temperature measurement rate of 10 ° C./min at a measurement temperature range of 0 ° C. to 200 ° C., a temperature decrease rate of 10 ° C./min, and temperature control of Heat-cool-Heat. Analysis is performed based on the data in Heat, and an extension line of the baseline before the rising of the first endothermic peak and a tangent showing the maximum slope between the rising portion of the first peak and the peak apex are drawn, and the intersection point As the glass transition point.

  Moreover, it is preferable that the molecular weight measured by gel permeation chromatography (GPC) of non-crystalline resin is in the range of 10000-100000 in a weight average molecular weight (Mw). In the present invention, the molecular weight of the non-crystalline resin by GPC is a value measured as follows. That is, using an apparatus "HLC-8120GPC" (made by Tosoh Corp.) and a column "TSKguardcolumn + TSKgelSuperHZ-M 3-series" (made by Tosoh Corp.), tetrahydrofuran (THF) as a carrier solvent is flowed at a flow rate of 0. The sample is allowed to flow at 2 mL / min, and the measurement sample (noncrystalline resin) is dissolved in tetrahydrofuran so as to have a concentration of 1 mg / mL under dissolution conditions of 5 minutes treatment using an ultrasonic disperser at room temperature. The sample solution is treated with a 2 μm membrane filter to obtain a sample solution, 10 μL of this sample solution is injected into the apparatus together with the above carrier solvent, detected using a refractive index detector (RI detector), and the molecular weight distribution of the measurement sample A calibration curve measured using monodispersed polystyrene standard particles Calculated using. Ten points are used as polystyrene for calibration curve measurement.

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

  The polyvalent carboxylic acid is a compound having 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, nonane dicarboxylic acid, decane dicarboxylic acid, undecane dicarboxylic acid, dodecane dicarboxylic acid, tetradecane dicarboxylic acid Aliphatic dicarboxylic acids such as cyclohexanedicarboxylic acid; Aromatic dicarboxylic acids such as phthalic acid, isophthalic acid and terephthalic acid; Trivalent or higher polyvalent carboxylic acids such as trimellitic acid and pyromellitic acid And acids, anhydrides of these carboxylic acid compounds, and alkyl esters of 1 to 3 carbon atoms. One of these may be used alone, or two or more of these may be used in combination.

  The polyhydric alcohol is a compound having 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 Aliphatic diols such as 1,8-octanediol, 1,9-nonanediol, dodecanediol, neopentyl glycol, and 1,4-butenediol; and trivalent or higher polyvalent compounds such as glycerin, pentaerythritol, trimethylolpropane and sorbitol Alcohol etc. are mentioned. One of these may be used alone, or two or more of these may be used in combination.

The crystalline polyester resin preferably contains a hybrid polyester resin formed by bonding with different resins. This is because the vinyl-based polymer segment introduced into the hybrid polyester resin has a high affinity to the non-crystalline resin, and the hybrid crystalline resin becomes easily compatible with the non-crystalline resin. Therefore, when the crystalline polyester resin contains the 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 if the introduced mass percentage of the hybrid polyester resin is low compared to the non-hybrid crystalline resin. Becomes easy.

  The melting point (Tm) of the crystalline polyester resin (a hybrid crystalline polyester resin and a non-hybrid crystalline polyester resin described later) is preferably 55 to 90 ° C, more preferably 70 to 85 ° C. 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 Perkin-Elmer), the first heating process for raising the temperature from 0 ° C to 200 ° C at an elevation rate of 10 ° C / min, 200 ° C at a cooling rate of 10 ° C / min. Measured under the measurement conditions (temperature rise / cooling conditions) that sequentially go through a cooling process of cooling from 0 ° C to 0 ° C and a second temperature rise process of raising the temperature from 0 ° C to 200 ° C at a lifting rate of 10 ° C / min. Based on the DSC curve obtained by this measurement, the endothermic peak top temperature derived from the crystalline polyester resin in the first temperature raising process is taken as the melting point (Tm). As a measurement procedure, 3.0 mg of a measurement sample (crystalline polyester resin) is enclosed in an aluminum pan and set in a diamond DSC sample holder. The reference uses an empty aluminum pan.

In addition, the molecular weight of the crystalline polyester resin measured by gel permeation chromatography (GPC) is 5,000 to 50,000 in weight average molecular weight (Mw) and 1,500 to 25,000 in number average molecular weight (Mn). preferable. The molecular weight of the crystalline polyester resin measured by GPC 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, and more preferably 95/5 to 75/25. By setting the mass ratio (amorphous resin / crystalline resin) in the above range, the volume resistivity of the toner at 70 ° C. is in the range of 1 × 10 ^{13 to} 5 × 10 ¹⁶ Ω · cm. Becomes easy.

  The crystalline polyester resin is a crystalline polyester resin formed by chemically bonding a vinyl polymer segment and a polyester polymer segment (hereinafter, a crystalline polyester resin having a plurality of such segments is simply referred to as “hybrid crystalline polyester resin It is preferable that the crystalline resin not having the plural segments is simply referred to as "non-hybrid crystalline resin". Under the present circumstances, it is preferable that a vinyl-type polymeric segment and a polyester polymeric segment are crystalline polyester resin couple | bonded through both reactive monomers. The polyester polymerization segment is composed of a crystalline polyester resin.

[Vinyl-based polymerized segment]
The vinyl-based polymerized segment constituting the hybrid crystalline resin is composed of a resin obtained by polymerizing a vinyl-based monomer. Here, as the vinyl-based monomer, those described above as the monomers constituting the vinyl-based resin can be used in the same manner, and thus the detailed description is omitted here. The content of the vinyl-based polymerized segment in the hybrid crystalline resin (hybridization rate (“HB rate” described in the examples to be described later)) is not particularly limited, but the hybridization rate of the hybrid crystalline resin is The content is preferably 40% by mass or more, more preferably 40 to 60% by mass, and still more preferably 45 to 50% by mass.

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

[Bi-reactive monomer]
The “bi-reactive monomer” is a monomer that combines a polyester polymerization segment and a vinyl polymerization segment, and a hydroxyl group, a carboxy group, an epoxy group, and a primary group that form a polyester polymerization segment in the molecule. 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-based polymer segment. The dual reactive monomer is preferably a monomer 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, vinyl carboxylic acids are preferred.
Specific examples of the bireactive monomer include, for example, acrylic acid, methacrylic acid, fumaric acid, maleic acid and the like, and further, esters of these hydroxyalkyl (1 to 3 carbon atoms) Although good, acrylic acid, methacrylic acid or fumaric acid is preferable from the viewpoint of reactivity. The polyester polymerized segment and the vinyl polymerized segment are bonded via 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 dual reactive monomer used is 100 parts by mass of the total amount of vinyl monomers constituting the vinyl polymer segment. 1 to 10 parts by mass is preferable, and 4 to 8 parts by mass is more preferable.

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

In the present invention, although any of the above-mentioned production methods can be used, the method of the above item (2) is preferable. Specifically, a polyvalent carboxylic acid and a polyhydric alcohol which form a polyester polymerization segment, and a vinyl monomer and a bireactive monomer which form a vinyl polymerization segment are mixed, and a polymerization initiator is added. After the vinyl-based monomer and the bireactive monomer are addition-polymerized to form a vinyl-based polymer segment, it is preferable to carry out a polycondensation reaction by adding an esterification catalyst.
Here, various known catalysts can be used as catalysts for synthesizing polyester polymerized segments. 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 bis triethanol aminate. Acid (3,4,5-trihydroxybenzoic acid) etc. are mentioned.

<Release agent (Offset prevention agent)>
In the toner according to the present invention, in the case where the toner base particles are configured to contain a releasing agent, the releasing agent is particularly contained in an amorphous resin from the viewpoint of surface bleeding of the releasing agent at the time of fixing. It is preferable to be done.
As the wax, low molecular weight polypropylene, polyethylene, or oxidized polypropylene, polyolefin-based waxes such as polyethylene, and ester-based waxes such as behenyl behenate can be suitably used.
Specifically, for example, polyolefin wax such as polyethylene wax and polypropylene wax; branched hydrocarbon wax such as microcrystalline wax; long chain hydrocarbon wax such as paraffin wax and sazole wax; dialkyl such as distearyl ketone Ketone wax; carnauba wax, montan wax, behenyl behenate, trimethylolpropane tribehenate, pentaerythritol tetrabehenate, pentaerythritol diacetate dibehenate, glycerin tribehenate, 1,18-octadecanediol di Ester-based waxes such as stearate, tristearyl trimellitate, distearyl maleate, etc .; ethylenediamine behenylamide, trimellitic acid tristearylamide, etc. Such as amide waxes.
Among them, it is preferable to use one having a low melting point, specifically, one having a melting point in the range of 40 to 90 ° C., from the viewpoint of releasability at low temperature fixing. The content of the releasing agent in the toner base particles is preferably 1 to 20% by mass, 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, titanium iron trioxide and the like.
As a dye, for example, 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.
As a pigment, for example, 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 oranges 31, 43, C.I. I. Pigment yellows 14, 17, 74, 93, 94, 138, 155, 156, 158, 180, 185, C.I. I. Pigment green 7, C.I. I. Pigment blue 15: 3, and 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 ratio of the colorant in the toner base particles is preferably 1 to 10% by mass, and more preferably 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 contain external additive particles in addition to toner base particles. As the external additive particles, conventionally known external additive particles can be used. As such external additive particles, for example, inorganic oxide fine particles comprising silica fine particles, alumina fine particles, titania fine particles, etc., inorganic stearic acid compound fine particles such as aluminum stearate fine particles, zinc stearate fine particles, etc., or titanic acid Inorganic titanate compound fine particles such as strontium and zinc titanate may, for example, be mentioned. These can be used singly or in combination of two or more. These inorganic fine particles are preferably subjected to gloss treatment by a silane coupling agent, a titanium coupling agent, a higher fatty acid, a silicone oil or the like in order to improve the heat resistant storage stability and the environmental stability.

(Glass transition point of toner)
The glass transition point (Tg) of the toner according to the present invention is preferably in the range of 25 to 65 ° C, and 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 fixability and heat resistant storage stability can be obtained at the same time. The glass transition point of the toner is measured in the same manner as the noncrystalline resin except that the toner is used as a measurement sample.

(Toner particle size)
The average particle diameter 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 a volume-based median diameter. The average particle size can be controlled by the concentration of the coagulant used at the time of production, the amount of the organic solvent added, the fusion time, the composition of the binder resin (binder resin), and the like. When the volume-based median diameter is in the above range, it is possible to faithfully reproduce, for example, a very minute dot image of 1200 dpi level. The volume-based median diameter of toner is measured and calculated using a measuring device in which a computer system equipped with data processing software “Software V 3.51” is connected to “Multisizer 3” (manufactured by Beckman Coulter, Inc.) It is.

  Specifically, 0.02 g of a measurement sample (toner) 20 mL of a surfactant solution (for the purpose of dispersing toner particles, for example, a surfactant in which a neutral detergent containing a surfactant component is diluted 10 times with pure water The solution is added to the solution and subjected to ultrasonic dispersion for 1 minute to prepare a toner dispersion, and the toner dispersion is added to the beaker containing “ISOTON II” (manufactured by Beckman Coulter, Inc.) in the sample stand. Pipette until the indicated concentration on the measuring device is 8%. Here, by setting the concentration range, reproducible measurement values can be obtained. Then, in the measurement device, the number of measurement particle counts is 25,000, the aperture diameter is 100 μm, the frequency value of dividing the range of 2 to 60 μm which is the measurement range into 256 is calculated, and 50 from the larger volume integration fraction % Particle diameter is taken as the volume-based median diameter.

(Average Toner Roundness)
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, 0 More preferably, it is in the range of 950 to 0.995. When the average circularity is in the above range, individual toner particles are less likely to be broken, contamination of the triboelectric charging member is suppressed, the chargeability of the toner is stabilized, and the image quality is high in the formed image It becomes a thing. The average circularity of the toner is a value measured using “FPIA-2100” (manufactured by Sysmex Corporation). Specifically, the measurement sample (toner) is made to conform in a surfactant-containing aqueous solution, ultrasonic dispersion is performed for 1 minute and dispersed, and then the measurement condition HPF is measured by “FPIA-2100” (manufactured by Sysmex Corporation). In the (high magnification imaging) mode, shoot with the HPF detection number 3000-10000 proper density, calculate the degree of circularity for each toner particle according to the following formula, add the degree of circularity of each toner particle, and select all toner It is a value calculated by dividing by the number of particles. If the HPF detection number is in the above range, reproducibility can be obtained.
Circularity = (perimeter of a circle with the same projected area as particle image) / (perimeter of particle projection)

<Method of manufacturing toner>
<Method of Manufacturing 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 in the case of producing toner base particles according to the present invention by the emulsion aggregation method is, for example, a dispersion (a) containing non-crystalline resin fine particles and a dispersion (b) containing crystalline polyester resin fine particles And preparing the mixed dispersion, and raising the mixed dispersion to aggregate the non-crystalline resin fine particles and the crystalline polyester resin fine particles to form toner base particles. It is

Here, the "aqueous medium" refers to one containing at least 50% by mass of water, and examples of components other than water include organic solvents that are soluble 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 alcohol-based organic solvent such as methanol, ethanol, isopropanol or butanol, which is an organic solvent which does not dissolve the resin. Preferably, only water is used as the aqueous medium.
The manufacturing method can be configured, for example, as including the following steps. Here, the following example describes the case where the non-crystalline resin fine particles contain a releasing agent, the crystalline polyester resin fine particles are contained, and the toner base particles further contain a colorant. And the technical scope of the present invention is not limited to these forms.

(1) preparing a dispersion (a) containing a non-crystalline resin fine particle containing a release agent, the step of preparing the dispersion (a),
(2) A dispersion liquid (b) in which a crystalline polyester resin is dissolved in an organic solvent, emulsified and dispersed in an aqueous dispersion medium, and the organic solvent is removed to prepare a dispersion (b) containing crystalline polyester resin fine particles Preparation step),
(3) A process of preparing a mixed dispersion, adding the dispersion (a) prepared in the above (1) and the dispersion (b) prepared in the above (2) to an aqueous medium to prepare a mixed dispersion,
(4) A coagulated particle forming step of forming toner base particles by aggregating non-crystalline resin fine particles and crystalline resin fine particles by raising the temperature of the mixed dispersion prepared in the above (3).
(5) Aging step of aging the aggregated particles formed in the above (4) with thermal energy to control the shape and obtaining toner base particles;
(6) a cooling step of cooling the dispersion of toner base particles;
(7) A filtration / washing step of filtering out toner base particles from an aqueous medium and removing a surfactant and the like 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 may include those comprising the steps (5) to (8) which can be added to the steps (1) to (4) as required. it can.

In carrying out the above-described respective steps, conventionally known findings can be referred to as appropriate. For example, the dispersion (a) containing the non-crystalline resin fine particles described above and the dispersion (b) containing the crystalline resin fine particles are prepared using various emulsification methods such as a method of emulsifying with mechanical shear force. Although it is possible, it is preferable to prepare using a method called phase inversion emulsification method. In particular, with regard to the dispersion (b), when using one prepared by the 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 superior at the point which is not dispersed by shear force forcibly.
In the “phase inversion emulsification method”, the resin is dissolved in an organic solvent to obtain a resin solution, the neutralization process in which a neutralizing agent is added to the resin solution, and the resin solution after neutralization is dispersed in water. A dispersion liquid of resin fine particles is obtained through an emulsification step of obtaining a resin emulsion liquid by emulsification and dispersion in a medium, and a desolvation step of removing an organic solvent from the resin emulsion liquid. The particle size of the resin fine particles in the dispersion can be controlled by changing the amount of the neutralizing agent added.

  Further, by providing a shell layer on the surface of the toner base particle as a core, it is possible to obtain a toner base particle of a core-shell structure. With the core-shell structure, the heat resistant storage stability and the low temperature fixability can be further improved. In order to produce toner base particles having a core-shell structure, for example, in the above-mentioned production method, after the aggregated particle forming step of (4) above, toner base particles prepared in the following steps: (4 ′) above (4) Of forming a shell on the surface of the core particle by adding the dispersion liquid for shell (c) containing non-crystalline resin fine particles to the mixed dispersion using core particles as core particles, and then carrying out the above (5) The following steps may be performed.

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

<Developer for electrostatic image development>
The toner according to the present invention can be used as a magnetic or nonmagnetic 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, as the carrier, magnetic particles made of conventionally known materials such as metals such as iron, ferrite and magnetite, and alloys of those metals and metals such as aluminum and lead are used. In particular, ferrite particles are preferable. In addition, as the carrier, a coated carrier in which the surface of the magnetic particles is coated with a coating agent such as a resin, or a dispersion type carrier obtained by dispersing magnetic powder in a binder resin may be used.
The volume-based median diameter of the carrier is preferably 20 to 100 μm, and more preferably 25 to 80 μm. The volume-based median diameter of the carrier can be measured typically by a laser diffraction type particle size distribution measuring apparatus "HELOS" (manufactured by SYMPATEC) equipped with a wet disperser.

  In the following examples, unless otherwise stated, "parts" and "%" mean "parts by mass" and "% by mass", respectively, and each operation is performed at room temperature (25.degree. C.). The present invention is not limited to the examples.

<Production of Toner>
(Synthesis of crystalline polyester (1))
281 parts by mass of tetradecanedioic acid and 206 parts by mass of 1,6-hexanediol are charged into a 5 L reaction vessel equipped with a stirrer, a temperature sensor, a cooling pipe and a nitrogen introduction device, and this system is stirred for 1 hour The internal temperature was raised to 190 ° C. After confirming that the state 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 the charged amount of tetradecanedioic acid. Thereafter, while distilling off the water to be produced, the internal temperature is raised from 190 ° C. to 240 ° C. over 6 hours, and the polymerization is carried out by continuing the dehydration condensation reaction for 6 hours under the conditions of 240 ° C. Thus, a crystalline polyester resin (1) was obtained. The number average molecular weight (Mn) was 4400.

(Synthesis of Styrene Acrylic Bonded Hybrid Crystalline Polyester (1))
Raw material monomers of a styrene-acrylic resin unit having a composition shown below containing a bireactive monomer and a radical polymerization initiator 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, the following raw material monomers for the crystalline polyester resin unit can be dehydrated with a nitrogen introducing pipe, The flask was placed in a four-necked flask equipped with a tube, a stirrer and a thermocouple, and heated to dissolve at 170 ° C.
271 parts by mass of tetradecanedioic acid 118 parts by mass of 1,6-hexanediol

Next, while stirring the contents of the flask, the raw material monomer of the styrene-acrylic resin unit is dropped over 90 minutes, and after aging for 60 minutes, the unreacted styrene-acrylic resin unit under reduced pressure (8 kPa) Raw material monomers were removed. The amount of monomer removed at this time was very small relative to the raw material monomer ratio of the above resin.
Then, 0.8 parts by mass of Ti (OBu) ₄ as an esterification catalyst is added, the temperature is raised to 235 ° C., and the reaction is conducted 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 is 10% by mass based on 100% by mass of the total amount of the hybrid crystalline polyester resin (1). Alternatively, the number average molecular weight (Mn) of the hybrid crystalline polyester resin (1) was 6400.

(Synthesis of Styrene-Acryl Bonded Hybrid Crystalline Polyester (2))
A hybrid crystalline polyester resin (2) was obtained in the same manner as the above-mentioned hybrid crystalline polyester (1) except that the raw material monomers of the crystalline polyester resin unit having the composition shown below were 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 pipe, a stirrer and a nitrogen introducing pipe, 316 parts by mass of 2 mol adduct of bisphenol A, 80 parts by mass of terephthalic acid, 34 parts by mass of fumaric acid and titanium tetraisopropoxide as a polycondensation catalyst Two parts by mass were divided into 10 portions and reacted at 200 ° C. for 10 hours while distilling off water generated under a nitrogen stream.
Next, the reaction was performed under reduced pressure of 13.3 kPa (100 mmHg), and when the softening point reached 104 ° C., the reaction was taken out to obtain a non-crystalline polyester resin (1).

(Preparation of Dispersion of Crystalline Polyester (1), Hybrid Crystalline Polyester (1) to (2), Non-Crystalline Polyester (1))
100 parts by mass of the crystalline polyester resin (1) was dissolved in 400 parts by mass of ethyl acetate. Next, 25 parts by mass of a 5.0% by mass aqueous solution of sodium hydroxide was added to form a resin solution. The resin solution was introduced into a container having a stirrer, and while stirring the resin solution, 400 parts by mass of a 0.26% by mass aqueous sodium lauryl sulfate solution was dropwise added and mixed over 30 minutes. The liquid in the reaction vessel became cloudy during the dropping of the sodium lauryl sulfate aqueous solution. Furthermore, the entire amount of the aqueous sodium lauryl sulfate solution was dropped to prepare an emulsion in which resin solution particles having a solid content of 20% were uniformly dispersed.
The other resin was also subjected to the same operation to obtain an emulsified dispersion having a solid content of 20%.

(Preparation of styrene-acrylic resin particle dispersion (1) for wax-containing core)
[First Stage Polymerization]
In a reaction vessel equipped with a stirrer, a temperature sensor, a temperature controller, a condenser 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 The anionic surfactant solution was charged, and the internal temperature was raised to 80 ° C. while stirring under a nitrogen stream at a stirring speed of 230 rpm. After adding 9.0 parts by mass of a polymerization initiator "potassium persulfate: KPS" to this surfactant solution and making the internal temperature 78.degree. C.,
Styrene 540 parts by mass n-butyl acrylate 270 parts by mass Methacrylic acid 65 parts by mass n-octylmercaptan A solution (1) consisting of 17 parts by mass is added dropwise over 3 hours, and heating / stirring is continued for 1 hour at 78 ° C. The polymerization (first stage polymerization) was carried out to prepare “a dispersion of resin particles [a1]”.

[Second-step polymerization: formation of an intermediate layer]
In a flask equipped with a stirrer,
Styrene 94 parts by mass n-butyl acrylate 60 parts by mass methacrylic acid 11 parts by mass n-octylmercaptan 5 parts by mass of paraffin wax (melting point: 73 ° C.) as a release agent is added to a solution (2) consisting of 5 parts by mass The mixture was heated to 85 ° C. for dissolution to prepare “monomer solution [2]”.

  Here, a surfactant solution in which 2 parts by mass of an anionic surfactant “sodium lauryl sulfate” was dissolved in 1100 parts by mass of ion exchange water was heated to 90 ° C. After adding 28 parts by mass of “dispersion liquid of resin particles [a1]” to this surfactant solution in terms of solid content of resin particles [a1], a mechanical disperser “Claremix” (M.M.) having a circulation path The monomer solution [2] was mixed and dispersed for 4 hours according to Technics Co., Ltd.) to prepare a dispersion liquid containing emulsified particles with a dispersed particle diameter of 350 nm.

  To the dispersion, 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, and this system is heated and stirred at 90 ° C for 2 hours for polymerization. The “second-stage polymerization” was performed to prepare “a 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-mentioned "dispersion liquid of resin particles [a2]". ,
Styrene 230 parts by mass n-butyl acrylate 100 parts by mass n-octylmercaptan A solution (3) consisting of 5.2 parts by mass was added dropwise 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 styrene- acryl resin particle dispersion liquid (1) for wax containing cores" with which resin particle (1) for cores was disperse | distributed in anionic surfactant solution. The wax content is 9.8% with respect to 100% of resin.

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

(Preparation of Dispersion of Wax-Containing Noncrystalline Polyester Resin (1) Particles)
100 parts by mass of the non-crystalline polyester resin (1) is dissolved in 400 parts by mass of ethyl acetate (manufactured by Kanto Chemical Co., Inc.) with stirring and dissolved, then 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.

Subsequently, it mixes with 638 mass parts of 0.26 mass% concentration sodium lauryl sulfate solutions prepared beforehand, and carries out ultrasonic dispersion for 30 minutes by V-LEVEL300microA with ultrasonic homogenizer "US-150T" (made by Nippon Seiki Seisakusho), stirring. did.
After that, using a diaphragm vacuum pump V-700 (manufactured by Nippon Buchi) while heating to 50 ° C., ethyl acetate is completely removed while stirring under reduced pressure for 5 hours, and the solid content is 20 parts by mass A dispersion of wax-containing non-crystalline polyester resin (1) particles was obtained.

(Preparation of aqueous dispersion of colorant fine particles (Cy 1))
90 parts by mass of sodium lauryl sulfate was added to 1600 parts by mass of ion exchange water. While this solution is being stirred, 420 parts by mass of copper phthalocyanine (CI Pigment Blue 15: 3) is gradually added, and then dispersion treatment is carried out using a stirring apparatus "Clairemix" (manufactured by M. Technics Co., Ltd.) Thus, an aqueous dispersion (Cy1) of colorant fine particles was prepared. The volume-based median diameter of the colorant fine particles contained in the dispersion liquid (Cy1) was 130 nm.

(Preparation of Toner (1))
After charging 170 parts by mass (solid content conversion) of the styrene-acrylic resin particle dispersion (1) for wax-containing core and 2000 parts by mass of ion-exchanged water into a reaction vessel equipped with a stirrer, a temperature sensor and a cooling pipe, The pH of the solution was adjusted to 10 by addition of 5 mol / l aqueous sodium hydroxide solution.
Thereafter, 10 parts by mass (in terms of solid content) of the colorant fine particle aqueous dispersion (Cy1) is added, and then an aqueous solution in which 60 parts by mass of magnesium chloride is dissolved in 60 parts by mass of ion exchanged water is stirred at 30.degree. 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 crystalline polyester resin fine particle dispersion (1) is added over 10 minutes, and then heated to 82 ° C. over 60 minutes to 82 ° C. The particle growth reaction was continued while holding it.

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

Next, the solid-liquid separated, dewatered toner cake is re-dispersed in ion-exchanged water and the solid-liquid separated operation is repeated three times, followed by washing at 40 ° C. for 24 hours to obtain a toner matrix (1). The
0.6 parts by mass of hydrophobic silica (number average primary particle diameter = 12 nm, degree of hydrophobicity = 68) and hydrophobic titanium oxide (number average primary particle diameter = 20 nm) based on 100 parts by mass of the obtained toner particles (1X) Degree of hydrophobization = 63) 1.0 parts by mass is added, and after mixing at 32 ° C for 20 minutes with "Henshell mixer" (manufactured by Nippon Coke Industry Co., Ltd.) at a rotor peripheral speed of 35 mm / sec, 45 μm A toner (1) was produced by the external additive treatment of removing coarse particles using a sieve with an opening.

(Preparation of Toner (2))
Toner (1) is used 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 to be used is changed to 20 parts by mass (solid content conversion) It produced similarly and obtained the toner (2).

(Preparation of Toner (3))
Similar to toner (1) except that the dispersion of styrene-acrylic resin particles (1) for wax-containing core of toner (1) is changed to dispersion (1) of wax-containing non-crystalline polyester resin (1) particles It produced and obtained the toner (3).

(Preparation of Toner (4))
The styrene-acrylic resin particle dispersion (1) for wax-containing core of toner (1) is changed to a styrene-acrylic resin particle dispersion (2) for wax-containing core, and 10 parts by mass of non-crystalline polyester (1) dispersion (Solid content) was dropped over 10 minutes when the toner reached 6 μm. Other than that was produced similarly to the toner (1).

(Preparation of Toner (5))
The styrene-acrylic resin particle dispersion (1) for wax-containing core of toner (1) is changed to a styrene-acrylic resin particle dispersion (2) for wax-containing core, and crystalline polyester (1) dispersion of toner (1) A toner (1) was prepared in the same manner as the toner (1) except that the solution was changed to 30 parts by mass (solid content conversion).

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

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

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

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

(Preparation of Toner (10))
A toner (7) was prepared in the same manner as 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 electrostatic image development)
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 charged into a high-speed mixer equipped with a stirring blade, and stirred and mixed at 120 ° C. for 30 minutes A resin coating 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 by a laser diffraction type particle size distribution measuring apparatus "HELOS" (manufactured by Sympathic) equipped with a wet disperser. Toners 1 to 10 are added to the above carrier so that the toner concentration is 6% by mass, respectively, and introduced into a micro V-type mixer (Tsukai Rikakai Kikai Co., Ltd.) and mixed for 30 minutes at a rotational speed of 45 rpm. 1 to 10 were produced (Table 1).

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

[Evaluation method]

(Sticking force evaluation)
100 sheets of a solid image (toner adhesion: 10.5 g / m ² ) were output on both sides using “bizhub PRESS C 1070 (manufactured by Konica Minolta)” (paper type: OK top coated paper (manufactured by Oji Paper Co., Ltd.) A3 157 g / m ² ). The formed solid image was printed and loaded. Of the stacked sheets S, extract the 70th to 80th sheets from the top, and place them on a flat table, affix the tape T to the top end of the top sheet S and slowly in the horizontal direction H I slipped.
At this time, the second lower 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 only. This measurement was repeated 10 sheets in order from the top, and the average value of the force indicated by the spring was taken as the sticking force (FIG. 3). It was considered as a practicable level when the sticking force was 1.5 N or less.

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

(Fixation separation evaluation)
Using “bizhub PRESS C 1070 (manufactured by Konica Minolta)”, the margin tip of a solid image (toner adhesion amount: 8.0 g / m ² , paper: mondi 90) at normal temperature and normal humidity (temperature 20 ° C., relative humidity 55%) Was evaluated, and the minimum margin that could be passed in 5 consecutive sheets was evaluated.
The smaller the value of the margin amount, the better the separation performance.
(Judgment criteria)
:: margin less than 4 mm ○: margin 4 or more and less than 7 mm :: margin 7 or more and less than 10 mm ×: margin 10 mm or more

(Fogging measurement)
In the measurement of fogging, the density of the blank sheet of the image support was measured at 20 points of A4 size, and the average value was taken as the blank sheet density. The absolute image density of each sample was measured and averaged, and the value obtained by subtracting the white paper density from this average density was evaluated as the fog density. If the fogging density is 0.01 or less, the fogging was regarded as passing. The concentration was measured using a reflection densitometer "RD-918" (manufactured by Macbeth).
:: less than 0.003 ○: 0.003 or more to less than 0.006 Δ: 0.006 or more to 0.010 or less ×: a value larger than 0.010

(Comprehensive judgment)
Comprehensive judgment was judged as follows from the comprehensive point of each evaluation item, and it showed in Table 2.
:: The number of ◎ in each evaluation item is 2 or more ○: The number of ◎ in each evaluation item is 1 ×: the number of x in each evaluation item is 1 or more

DESCRIPTION OF SYMBOLS 8 Fixing devices 10Y, 10M, 10C, 10K Image forming unit 21 Paper feeding unit 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 device F Suction fan GH Image forming device main body N Nip section P, S Paper X Electrophotographic image forming device YS Image reader d Document T Tape H Horizontal direction

Claims (6)

Electrophotographic image formation using a means for separating the sheet from the heating / pressurizing section by jetting air onto the sheet in the step of heating / pressurizing the sheet carrying the electrostatic image developing toner to fix the toner image Method,
The toner for electrostatic charge image development contains toner base particles containing at least a colorant, a release agent, and a styrene-acrylic resin and a crystalline polyester resin as a binder resin, and the electrostatic charge image development at 70 ° C. An electrophotographic image forming method characterized in that a volume resistivity of the toner for use is in a range of 1 × 10 ^{13 to} 5 × 10 ¹⁶ Ω · cm. The electrophotographic image forming method according to claim 1, wherein the binder resin further contains a non-crystalline polyester resin. The crystalline polyester resin is, electrophotographic imaging process according to claim 1 or claim 2, characterized in that it is contained in the range of 3 to 30 wt% based on the total weight of the binder resin. The electrophotographic image forming method according to any one of claims 1 to 3, wherein the crystalline polyester resin contains a hybrid polyester resin formed by bonding with different resins.   The electrophotographic image forming method according to any one of claims 1 to 4, wherein the toner base particles have a core-shell structure.   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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