JP5151863B2 - Toner for electrostatic image development - Google Patents

Description

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

In recent years, an image forming apparatus that forms an image by an electrophotographic method using toner for developing an electrostatic image has been widely used as a copying machine in an office or the like, and can form a high-quality color image particularly at high speed. The color image forming apparatus that can be used is also referred to as a “digital printing machine”, and is suitably used for creating a document on which variable information such as direct mail and a billing statement is to be printed, and further, no printing plate is required. Therefore, it has begun to spread as an alternative to the offset printing press that has been mainly used for commercial printing.
In addition, an image forming apparatus in which the image forming speed is particularly increased is a so-called option for processing a transfer sheet on which an image such as a stapling function, a bookbinding function, and a punch punching function is formed. Equipment (finishers) is often used with it attached. According to the image forming apparatus provided with such optional equipment, it is possible to further improve the efficiency of the work related to image formation.
Various image forming apparatuses having new functions have been proposed. Particularly, those having high speed and high function have a high usage rate and a large number of printed sheets. Along with this, the consumption rate of consumables such as toner is increased, and studies for differentiating from others are being actively conducted.

  In an image forming apparatus called a digital printing machine, the formed image itself may be used as a product. Therefore, in addition to excellent color reproducibility, image density can be adjusted in image formation from thousands to tens of thousands of times. There is a demand for image density stability capable of forming a large amount of images with stable image quality without fluctuations, and the formed image itself is required to have light resistance and scratch resistance.

Thus, since the image forming apparatus forms an image (toner image) on the transfer paper by frictionally charging the electrostatic image developing toner, there are various demands for images formed by the image forming apparatus. In order to cope with the above, the electrostatic image developing toner used for forming this image has been studied and various toners have been proposed.
Specifically, from the viewpoint of image density stability, as a toner for developing an electrostatic image, a stable toner charge amount is obtained even when the image forming environment (specifically, temperature and humidity) changes. For this purpose, a toner containing a charge control agent has been proposed as a toner constituent material (see, for example, Patent Document 1), but a sufficiently high image density stability required can be obtained. Not.
From the viewpoint of light resistance, a toner for developing an electrostatic charge image that includes a light resistance improver and an ultraviolet absorber as a toner forming material has been proposed (see, for example, Patent Document 2). According to the toner for developing an electrostatic image, color reproducibility and light resistance can be obtained, but image density stability and scratch resistance required together with these toners cannot be obtained.

  As a toner for developing an electrostatic image, a toner having a low fixable temperature (hereinafter also referred to as “low temperature fixing toner”) has been proposed in order to save energy and reduce running cost. The use of toner when forming a large amount of images with a digital printing machine has been studied. However, there is a problem that a document offset phenomenon occurs in practical use.

  Here, the “document offset phenomenon” refers to a transfer sheet (hereinafter referred to as “double-sided image transfer sheet”) on which images are formed on both sides of the transfer sheet, particularly when the image forming apparatus forms an image on both sides of the transfer sheet. Is caused by the fact that the image (toner image) formed on the transfer paper is not sufficiently cooled when discharged from the image forming apparatus. Specifically, a plurality of double-sided image transfer sheets discharged from the image forming apparatus are overlapped on a paper discharge tray, so that one of the double-sided images is placed between the two overlapped double-sided image transfer sheets. In the portion where the image forming unit related to the transfer paper and the non-image forming unit related to the other double-sided image transfer paper are overlapped, image transfer occurs in the non-image forming unit. In the portion where the image forming portions are overlapped with each other, the images related to the overlapped image forming portions are stuck to each other. In addition, when an optional device is to be used, the images are stuck to the double-sided image transfer paper superimposed on the paper discharge tray, and the degree of sticking between the images is crisp when peeling. If this is the case, it will not be possible to make multiple sheets of double-sided image transfer paper neatly aligned (good paper alignment state) on the output tray, and processing with optional equipment will be in the expected state. You may not be able to do it. In addition, when a book that has been bound by using an optional function is stored for a long period of time, there is a possibility that the images overlapped, image transfer, image loss, or the like may occur on the overlapped pages.

The fundamental cause of the occurrence of such document offset phenomenon is that in the toner for developing an electrostatic charge image (low temperature fixing toner), the melting characteristic of the toner is shifted to the low temperature side for the purpose of reducing the fixable temperature. When a high-speed digital printing machine is used to form a large amount of images, the image (toner image) formed on the transfer paper is discharged without being sufficiently cooled. It will be mentioned.
Thus, from the viewpoint of suppressing the occurrence of the document offset phenomenon, it is important that the toner for developing an electrostatic charge image can obtain sufficient heat-resistant storage stability for an image (toner image) to be formed. Is done.

  However, as a toner for developing an electrostatic image, sufficient studies have been made in order to obtain heat-resistant storage stability of the toner particles constituting the toner for developing an electrostatic image. For example, a core-shell technology or the like is used for toner production. (See, for example, Patent Document 3 and Patent Document 4), a technique for obtaining heat-resistant storage stability of the toner particles themselves, and heat-resistant storage of toner images formed on transfer paper. This is different from the technique for obtaining the heat resistance (see, for example, Patent Document 5), and the present situation is that sufficient studies have not been made to obtain the heat-resistant storage stability of the toner image.

JP-A-5-66612 JP 2008-52086 A JP 2006-349722 A JP 2008-64837 A JP 2007-225736 A

  The present invention has been made on the basis of the above circumstances, and the object thereof is to form an image having a stable image density regardless of the image forming environment, and to provide excellent light resistance to the formed image. It is an object of the present invention to provide a toner for developing an electrostatic charge capable of obtaining a high level of resistance, scratch resistance and heat-resistant storage stability.

The electrostatic image developing toner of the present invention is an electrostatic image developing toner containing a resin and a colorant,
An electrostatic image developing toner comprising a compound represented by the following general formula (1):

[Wherein R ¹ represents an alkyl group having a secondary carbon atom or an alkyl group having a tertiary carbon atom, and R ² represents a sulfonic acid group, —SO ₂ NR ⁴ R ⁵ group (where R ⁴ and R ⁵ each independently represents a hydrogen atom, an alkyl group or an aryl group.) Or —SO ₂ OR ⁶ group (where R ⁶ represents an aliphatic hydrocarbon group, an aromatic hydrocarbon group or a heterocyclic ring) Group). R ³ represents a hydrogen atom or a chlorine atom. ]

  The toner for developing an electrostatic charge image of the present invention contains a release agent, and the release agent is a mixture of a branched paraffin compound and a linear paraffin compound, and absorbs heat within a range of 60 to 105 ° C. It is preferable that it has a peak.

  According to the toner for developing an electrostatic charge image of the present invention, a specific benzotriazole compound is contained, and this specific benzotriazole compound has an ultraviolet absorption performance and is derived from the structure thereof, so that it is used in an image forming environment. Regardless of this, it has a charge control function that can keep the charge amount of the toner constant, and an image surface curing function that can increase the hardness of the surface of the toner image, and also acts on the resin constituting the toner. Thus, in the image forming process, the toner image has a heat resistance improving action that can have a high heat resistance. Based on stabilization of development characteristics and transfer characteristics, images with stable image density can be obtained regardless of the image forming environment. In the formed image, it is possible to obtain excellent light resistance based on the ultraviolet absorption action and excellent scratch resistance based on the image surface curing action, and it is expressed in the image forming process. The heat-resistant storability of the image is obtained based on the heat-resistance improving action, and the occurrence of the document offset phenomenon can be suppressed by the heat-resistant storability of the image.

  The toner for developing an electrostatic image of the present invention comprises toner particles containing a resin and a colorant, and is a compound represented by the above general formula (1) (hereinafter also referred to as “specific benzotriazole compound”). It is characterized by containing.

In the general formula (1) showing the specific benzotriazole compound, R ¹ is an alkyl group having a secondary carbon atom (hereinafter also referred to as “secondary alkyl group”) or an alkyl group having a tertiary carbon atom. (Hereinafter also referred to as “tertiary alkyl group”).
Each of the secondary alkyl group and the tertiary alkyl group representing the group R ¹ may be unsubstituted or may have a substituent.

The secondary alkyl group representing the group R ¹ is preferably a group having 4 to 12 carbon atoms, and specifically includes, for example, a sec-butyl group, a sec-pentyl group, a sec-hexyl group, and a sec-octyl group. , Sec-dodecyl group and the like.

As the tertiary alkyl group represented by group R ^1, preferably those having a carbon number of 4 to 6, specifically, include for example tert- butyl group, tert- pentyl group, such as tert- hexyl It is done.

In the general formula (1), R ² represents a sulfonic acid group, a sulfonic acid amide group, or a sulfonic acid ester group.
This group R ² may be bonded to any carbon atom other than the carbon atom at position number 2 to which the hydroxy group is bonded and the carbon atom at position number 3 to which the group R ¹ is bonded in the phenyl group. Although it is good, it is preferably bonded to the carbon atom at position number 5 constituting the phenyl group.

Examples of the sulfonic acid group representing the group R ² include —SO ₃ H group and —SO ₃ Na group.

The —SO ₂ NR ⁴ R ⁵ group (hereinafter also referred to as “sulfonic acid amide group”) representing the group R ² is such that R ⁴ and R ⁵ each independently represents a hydrogen atom, an alkyl group or an aryl group. It is a group to show.

In this sulfonic acid amide group, the group R ⁴ and the group R ⁵ are a hydrogen atom, a linear or branched alkyl group having 1 to 8 carbon atoms, an unsubstituted or substituted alkyl group, or an unsubstituted or substituted group. It is preferable that it is a phenyl group which has, and it is especially preferable that it is a C1-C5 alkyl group.

Preferable specific examples of the sulfonic acid amide group representing the group R ² include an aminosulfonyl group (—SO ₂ —NH ₂ group), a methylaminosulfonyl group (—SO ₂ —NH (CH ₃ ) group), and an ethylaminosulfonyl group. (—SO ₂ —NH (C ₂ H ₅ ) group), propylaminosulfonyl group (—SO ₂ —NH (C ₃ H ₇ ) group), butylaminosulfonyl group (—SO ₂ —NH (C ₄ H ₉ )) Group), dimethylaminosulfonyl group (—SO ₂ —N (CH ₃ ) ₂ group), diethylaminosulfonyl group (—SO ₂ —N (C ₂ H ₅ ) ₂ group), diethanolaminosulfonyl group (—SO ₂ —N) (C ₂ H ₄ OH) ₂ group) and the like.

Also, -SO ₂ OR ⁶ groups represents a group R ² (hereinafter, also referred to as "sulfonic acid ester group.") Shows group R ⁶ is an aliphatic hydrocarbon group, an aromatic hydrocarbon group or heterocyclic group It is a group.

In this sulfonic acid ester group, the group R ⁶ is a linear or branched C 1-8 alkyl group having an unsubstituted or substituted group, or an unsubstituted or substituted phenyl group. Is preferred.

Preferable specific examples of the sulfonic acid ester group representing the group R ² include —SO ₂ OCH ₃ group, —SO ₂ OC ₂ H ₅ group, —SO ₂ OC ₆ H ₅ group, —SO ₂ OC ₃ H ₇ group, -SO ₂ OC ₄ H _{9 group, -SO 2 OCH (CH 3)} 2 _{group, -SO 2 OCH 2 C (CH} 3) 3 group, -SO ₂ OC (CH ₃₎ such as ₃ group can be mentioned.

In the general formula (1), R ³ represents a hydrogen atom or a chlorine atom.

Preferable specific examples of the specific benzotriazole compound represented by the general formula (1) include compounds represented by the following formulas (1-1) to (1-16).
Among these, in general formula (1), R ¹ is a sec-butyl group and R ² is a sulfonic acid group, that is, compounds represented by formulas (1-1) and (1-2) Is particularly preferred.

  The content ratio of the specific benzotriazole compound in the toner for developing an electrostatic charge image of the present invention is preferably 1 to 12% by mass, and particularly preferably 3 to 8% by mass with respect to the whole toner.

When the content of the specific benzotriazole compound is excessive, the toner fluidity and the cleaning properties are reduced by reducing the fluidity of the toner, or the heat resistance of an image formed due to excessive plasticizer action. Preservability may be reduced.
On the other hand, when the content ratio of the specific benzotriazole compound is too small, it is impossible to form an image having a sufficiently stable image density, and the formed image has sufficient light resistance, scratch resistance and heat resistance. Preservability may not be obtained.

The toner for developing an electrostatic charge image of the present invention preferably contains a release agent.
Further, the release agent constituting the toner for developing an electrostatic charge image has an endothermic peak, that is, an endothermic main peak value in a DSC endothermic curve, from the viewpoint of preventing gloss uniformity and toner filming. It is preferable that it consists of a compound which has in the range of 70 degreeC, and also in the range of 70-90 degreeC. Moreover, it is preferable that the compound which comprises a mold release agent is a thing whose tangential separation temperature in a DSC endothermic curve is 40 degreeC or more.

Preferable specific examples of the release agent include those obtained by mixing a branched paraffin compound and a linear paraffin compound.
In the mixture of the branched paraffin compound and the linear paraffin compound, the mixing ratio (branched paraffin compound: linear paraffin compound) is 10: 1 from the viewpoint of preventing gloss uniformity and toner filming. It is preferable that it is 90-30: 70 (mass ratio).
Here, the mixing ratio of the branched paraffin compound and the linear paraffin compound can be confirmed by C ¹³ NMR measurement.

In addition to the mixture of branched paraffin compound and linear paraffin compound, the release agent includes petroleum wax such as ester wax, paraffin wax, microcrystalline wax, petrolactam and derivatives thereof; montan wax and derivatives thereof; Fischer-Tropsch Hydrocarbon wax obtained by the method and derivatives thereof; polyolefin wax such as polyethylene wax and derivatives thereof; natural wax such as carnauba wax and candelilla wax and derivatives thereof can be used.
Derivatives include oxides, block copolymers with vinyl monomers, and graft modified products.

  The content of the release agent in the toner for developing an electrostatic charge image of the present invention is preferably 4 to 25% by mass, and particularly preferably 7 to 15% by mass with respect to the whole toner.

  Specific examples of the resin constituting the electrostatic image developing toner of the present invention include, for example, styrene resins, acrylic resins such as alkyl acrylates and alkyl methacrylates, vinyl polymers such as styrene-acrylic copolymer resins, Examples include olefin resins, polyester resins, isocyanate-modified polyester resins, urea-modified polyester resins, and epoxy-modified polyester polyol resins. Of these, styrene-acrylic copolymer resins are particularly suitable. The reason can be presumed to be that a specific benzotriazole compound is easily dispersed because the molecular main chain of the resin is flexible.

Further, as a polymerizable monomer for obtaining a resin, for example, a styrene monomer such as styrene, methyl styrene, methoxy styrene, butyl styrene, phenyl styrene; methyl acrylate, ethyl acrylate, butyl acrylate, acrylic acid (Meth) acrylic acid ester monomers such as ethylhexyl, methyl methacrylate, ethyl methacrylate, butyl methacrylate, and ethylhexyl methacrylate; carboxylic acid monomers such as acrylic acid and fumaric acid can be used. . These can be used alone or in combination of two or more.
Examples of the monomer for obtaining the polyester resin include bisphenol A, bisphenol A ethylene oxide adduct, bisphenol A propylene oxide adduct, neopentyl glycol, cyclohexyl diol, butane diol, glycerin, adipic acid, phthalic acid, Examples include terephthalic acid, fumaric acid, succinic acid, itaconic acid, dodecenyl succinic acid, adipic acid and trimellitic acid.

In addition, as the colorant constituting the toner for developing an electrostatic charge image of the present invention, a known inorganic or organic colorant can also be used. Specific colorants are shown below.
Examples of the black colorant include carbon black such as furnace black, channel black, acetylene black, thermal black and lamp black, and magnetic powder such as magnetite and ferrite.
Examples of the colorant for magenta include C.I. I. Solvent Red 1, C.I. I. Solvent Red 3, C.I. I. Solvent Red 8, C.I. I. Solvent Red 23, C.I. I. Solvent Red 24, C.I. I. Solvent Red 25, C.I. I. Solvent Red 27, C.I. I. Solvent Red 30, C.I. I. Solvent Red 48, C.I. I. Solvent Red 49, C.I. I. Solvent Red 52, C.I. I. Solvent Red 58, C.I. I. Solvent Red 63, C.I. I. Solvent Red 81, C.I. I. Solvent Red 82, C.I. I. Solvent Red 83, C.I. I. Solvent Red 84, C.I. I. Solvent Red 100, C.I. I. Solvent Red 109, C.I. I. Solvent Red 111, C.I. I. Solvent Red 121, C.I. I. Solvent Red 122, C.I. I. Disper thread 9, C.I. I. Solvent Violet 8, C.I. I. Solvent Violet 13, C.I. I. Solvent Violet 14, C.I. I. Solvent Violet 21, C.I. I. Solvent Violet 27, C.I. I. Oil-soluble dyes such as Disperse Violet 1; I. Basic Red 1, C.I. I. Basic Red 2, C.I. I. Basic Red 9, C.I. I. Basic Red 12, C.I. I. Basic Red 13, C.I. I. Basic Red 14, C.I. I. Basic Red 15, C.I. I. Basic Red 17, C.I. I. Basic Red 18, C.I. I. Basic Red 22, C.I. I. Basic Red 23, C.I. I. Basic Red 24, C.I. I. Basic Red 27, C.I. I. Basic Red 29, C.I. I. Basic Red 32, C.I. I. Basic Red 34, C.I. I. Basic Red 35, C.I. I. Basic Red 36, C.I. I. Basic Red 37, C.I. I. Basic Red 38, C.I. I. Basic Red 39, C.I. I. Basic Red 40, C.I. I. Basic Violet 1, C.I. I. Basic Violet 3, C.I. I. Basic Violet 7, C.I. I. Basic Violet 10, C.I. I. Basic Violet 14, C.I. I. Basic Violet 15, C.I. I. Basic Violet 21, C.I. I. Basic Violet 25, C.I. I. Basic Violet 26, C.I. I. Basic Violet 27, C.I. I. And basic dyes such as basic violet 28.
These dyes can be used alone or in combination with a pigment. Examples of the colorant for orange or yellow include C.I. I. Pigment orange 31, C.I. I. Pigment orange 43, C.I. I. Pigment yellow 12, C.I. I. Pigment yellow 13, C.I. I. Pigment yellow 14, C.I. I. Pigment yellow 15, C.I. I. Pigment yellow 65, C.I. I. Pigment yellow 68, C.I. I. Pigment yellow 74, C.I. I. Pigment yellow 83, C.I. I. Pigment yellow 93, C.I. I. Pigment yellow 94, C.I. I. Pigment yellow 138, and the like.
Examples of the colorant for cyan include pigments and C.I. I. Solvent Blue 25, C.I. I. Solvent Blue 36, C.I. I. Solvent Blue 60, C.I. I. Solvent Blue 70, C.I. I. Solvent Blue 93, C.I. I. And dyes such as Solvent Blue 95.
These can be used alone or in combination with a pigment and a dye.
Of these, the dyes exemplified as the colorant for magenta are preferable.

The above colorants can be used alone or in combination of two or more.
Further, the content ratio of the colorant is in the range of 1 to 30% by mass, preferably 2 to 20% by mass with respect to the whole toner.

  As the colorant, a surface-modified one can also be used. As the surface modifier, conventionally known ones can be used, and specifically, silane coupling agents, titanium coupling agents, aluminum coupling agents and the like can be preferably used.

The toner for developing an electrostatic charge image of the present invention may contain an internal additive in addition to a resin, a colorant, a specific benzotriazole compound and a release agent.
As the internal additive, for example, a charge control agent made of a metal complex compound can be used in combination.

The toner for developing an electrostatic charge image of the present invention may be composed only of toner particles, but as an external additive (external additive), inorganic fine particles having a number average primary particle diameter of 4 to 800 nm or Particles such as organic fine particles or a structure in which a lubricant is added to colored particles may be used.
By adding an external additive, fluidity and chargeability are improved, and cleaning properties and transfer properties are improved.

  As the inorganic fine particles, conventionally known ones can be used. For example, silica fine particles, titania fine particles, alumina fine particles, strontium titanate fine particles and the like can be suitably used. Moreover, what hydrophobized these inorganic fine particles can also be used.

Specific examples of the silica fine particles include, for example, “R-805”, “R-976”, “R-974”, “R-972”, “R-812”, “R-809” manufactured by Nippon Aerosil Co., Ltd .; "HVK-2150", "H-200" manufactured by Hoechst, "TS-720", "TS-530", "TS-610", "H-5", "MS-5" manufactured by Cabot Is mentioned.
Specific examples of the titania fine particles include “T-805” and “T-604” manufactured by Nippon Aerosil Co., Ltd .; “MT-600S”, “MT-100B”, “MT-500BS”, “MT” manufactured by Teica. -600 "," MT-600SS "," JA-1 ";" TA-300SI "," TA-500 "," TAF-130 "," TAF-510 "," TAF-510T "manufactured by Fuji Titanium ; “IT-S”, “IT-OA”, “IT-OB”, “IT-OC” manufactured by Idemitsu Kosan Co., Ltd.
Specific examples of the alumina fine particles include “RFY-C” and “C-604” manufactured by Nippon Aerosil Co., Ltd. and “TTO-55” manufactured by Ishihara Sangyo Co., Ltd.

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

  As the lubricant, metal salts of higher fatty acids can be used. Specifically, salts of zinc stearate, aluminum, copper, magnesium, calcium, etc .; zinc oleate, manganese, iron, copper, magnesium, etc. Salts: salts of palmitic acid zinc, copper, magnesium, calcium, etc .; zincs of linoleic acid, salts of calcium, etc .; salts of ricinoleic acid zinc, calcium, etc.

  The addition amount of the external additive is preferably 0.1 to 10.0% by mass in the whole toner.

  In the method of adding the external additive, various known mixing apparatuses such as a Turbuler mixer, a Henschel mixer, a Nauter mixer, and a V-type mixer can be used.

  The electrostatic image developing toner of the present invention can be used as a magnetic or non-magnetic one-component developer, but can also be mixed with a carrier and used as a two-component developer.

  In the case where the toner for developing an electrostatic charge image according to the present invention is used as a two-component developer, the carrier is conventionally a metal such as iron, ferrite, or magnetite, or an alloy of such a metal with a metal such as aluminum or lead. From the above, magnetic particles made of a known material can be used, and ferrite particles are particularly preferable. The carrier preferably has a volume average particle diameter of 15 to 100 μm, particularly preferably 25 to 80 μm.

  Further, when used as a non-magnetic one-component developer, since the toner constituting the developer is charged by being rubbed and pressed against the charging member or the developing roller surface, the developing device Therefore, the entire image forming apparatus can be made compact, so that it is possible to form a full-color image having excellent color reproducibility even in a space-limited work environment. .

The electrostatic image developing toner of the present invention can be produced by a conventionally known method.
That is, a pulverization method that goes through a kneading step, a pulverization step and a classification step in this order, a so-called polymerization method in which a polymerizable monomer is polymerized and particles are formed while controlling the shape and size in the polymerization step (specifically, For example, an emulsion polymerization method, a suspension polymerization method, a polyester elongation method, or the like can be used.

  According to the toner for developing an electrostatic charge image of the present invention as described above, the specific benzotriazole compound is contained, and the specific benzotriazole compound has an ultraviolet absorption performance and is derived from the structure thereof to form an image. It has a charge control function that can keep the charge amount of the toner constant regardless of the environment, and an image surface curing function that can increase the hardness of the surface of the toner image. Since it has a heat resistance improving action that can make the toner image have high heat resistance in the image forming process by the action, the action of this specific benzotriazole compound, specifically, the charge control action Based on this, the development characteristics and transfer characteristics are stabilized, so that the image density is stable regardless of the image forming environment. An image can be formed, and in the formed image, excellent light resistance based on an ultraviolet ray absorbing action and excellent scratch resistance based on an image surface curing action can be obtained, and in the image forming process The heat-resistant storage stability of the image is obtained based on the heat-resistance improving effect that is expressed, and the occurrence of the document offset phenomenon can be suppressed by the heat-resistant storage stability of the image.

Therefore, according to the toner for developing an electrostatic charge image of the present invention, even when a large amount of image is formed in a color image forming apparatus called “digital printing machine” which is particularly speeded up, image formation is possible. In addition to being able to obtain high image density stability regardless of the environment, it is possible to obtain excellent light resistance and scratch resistance in the obtained image (toner image), and in addition,
Since the obtained image has high heat-resistant storage stability, the occurrence of document offset phenomenon is suppressed even when the fixable temperature is set to a low temperature such that the transfer paper temperature is less than 100 ° C., for example. can do.
Even when an optional device is attached to the image forming apparatus and images are formed on both sides of the transfer paper, the occurrence of document offset can be suppressed. Since the transfer paper on which images are formed on both sides can be neatly arranged, the processing by these optional devices can be performed in an intended state.
Furthermore, since the fixing temperature can be set to a low temperature such that the transfer paper temperature is less than 100 ° C., for example, the image forming apparatus is used in a color image forming apparatus called a “digital printing machine”. In this case, even if it is requested to use an offset printing paper other than the electrophotographic paper as the transfer paper, the transfer paper temperature of the offset printing paper having a large water content is set to the boiling point of water, that is, less than 100 ° C. Thus, an image can be formed without the adverse effect of curling the transfer paper by heat fixing.

The reason why the specific benzotriazole compound has a charge control action is that, due to its structure, it can accept the charge generated excessively by triboelectric charging, or it relaxes the excess charge based on the dipole relaxation action. This is thought to be due to the effect.
Further, the reason why the image surface curing action is obtained is considered to be due to the presence of hydrogen bonds.
The reason why the heat resistance improving effect is obtained is that when the toner in the image forming process is melted, the specific benzotriazole compound is hydrogenated between the resin and the resin in the process of cooling the molten toner to form a toner image. This is presumably because the glass transition temperature of the toner image forming material is increased by forming a bond or ionic crosslink.

  Hereinafter, specific examples of the present invention will be described, but the present invention is not limited thereto.

[Toner Production Example 1 (Toner Production Example by Crushing Method)]
(1) Synthesis Example of Titanium Catalyst In a reaction vessel equipped with a cooling tube, a stirring device, and a nitrogen introducing tube capable of bubbling in liquid, 1617 parts by mass of titanium diisopropoxybis (triethanolaminate) and 126 ion-exchanged water Titanium dihydroxy was prepared by charging the mass part and gradually raising the temperature in the reaction vessel to 90 ° C. while bubbling in liquid with nitrogen gas, followed by reaction (hydrolysis) at 90 ° C. for 4 hours. Bis (triethanolaminate) was obtained.

(2) Synthesis Example of Amorphous Polyester Resin In a reaction vessel equipped with a cooling pipe, a stirrer, and a nitrogen introduction pipe, 350 parts by mass of EO2 mol adduct of bisphenol A, 326 parts by mass of PO3 mol adduct of bisphenol A, 278 parts by mass of terephthalic acid, 40 parts by mass of phthalic anhydride, 2 parts by mass of titanium dihydroxybis (triethanolamate) as a condensation catalyst, and 50 parts by mass of the exemplified compound (1-1) as a specific benzotriazole compound were charged at a temperature of 230 The reaction was carried out over 10 hours while distilling off the water produced under a nitrogen stream under the condition of ° C. Further, the reaction was carried out under reduced pressure of 5 to 20 mmHg, and when the acid value became 2 or less, the temperature in the reaction vessel was cooled to 180 ° C., and then 62 parts by mass of trimellitic anhydride was added and sealed at normal pressure. The reaction product was taken out after making it react for 2 hours under. The obtained reaction product was cooled to room temperature and then pulverized to obtain a non-linear polyester resin (1).
The obtained non-linear polyester resin (1) does not contain tetrahydrofuran insolubles, has an acid value of 35, a hydroxyl value of 17, a glass transition temperature (Tg) of 69 ° C., a number average molecular weight (Mn ) Is 3920, molecular weight distribution (Mw / Mn) is 4.5, Mp is 11200, storage modulus is 7.8 × 104 Pa at 100 ° C. and 4.5 × 103 Pa at 150 ° C., softening point temperature is 143 ° C. Met. The ratio of components having a molecular weight of 1500 or less was 0.9%.

(3) Preparation Example of Toner Particles Nonlinear polyester resin (1) 100 parts by mass, linear paraffin wax (melting point 70 ° C.) 5 parts by mass as a release agent, and branched paraffin wax (melting point 84) isolated from microcrystalline wax C.) 1 part by mass, and C.I. 10 parts by weight of I Solvent Red was mixed for 20 minutes using a Henschel mixer at a temperature of 37 ° C. and a peripheral speed of a stirring blade of 20 m / s, then kneaded by a twin-screw extruder, and then an air-flow type pulverizer And toner particles (hereinafter referred to as “toner particles (1)”) having a volume-based median diameter of 6.5 μm were obtained by classification using an airflow classifier utilizing the Coanda effect.

(4) External Addition Treatment To 100 parts by mass of the obtained toner particles (1), an external additive consisting of 1 part by mass of colloidal silica “R972” (manufactured by Nippon Aerosil Co., Ltd.) is added, and Henschel mixer (Mitsui Miike Mining) A toner (hereinafter, referred to as “toner (1)”) was obtained by performing an external addition process using a product manufactured by Komatsu.
The shape and particle size of the toner particles (1) did not change depending on the addition of the external additive.

[Toner Production Example 2 (Example of Toner Production by Emulsion Association Method)]
(1) Preparation Example 1 of Colorant Fine Particle Dispersion
A surfactant aqueous solution was prepared by stirring and dissolving 11.5 parts by mass of sodium n-dodecyl sulfate in 160 parts by mass of ion-exchanged water. In this surfactant aqueous solution, C.I. Colorant fine particles in which colorant fine particles are dispersed by gradually adding 4825 parts by mass of I Solvent Red and then performing a dispersion treatment using “CLEARMIX W Motion CLM-0.8” (manufactured by M Technique Co., Ltd.) A dispersion (hereinafter referred to as “colorant fine particle dispersion (1)”) was prepared.
The volume-based median diameter of the colorant fine particles in this colorant fine particle dispersion (1) was measured to be 126 nm.
The volume-based median diameter is “MICROTRAC UPA 150” (manufactured by HONEYWELL), sample refractive index 1.59, sample specific gravity 1.05 (in terms of spherical particles), solvent refractive index 1.33, solvent viscosity 0 Measurement was performed by adjusting the zero point by introducing ion-exchanged water into the measurement cell under the measurement conditions of .797 (30 ° C.) and 1.002 (20 ° C.).

(2) Preparation example of core part resin particles (a) First stage polymerization (formation of core particles)
Anionic surfactant 4 made of sodium dodecyl sulfate (C ₁₀ H ₂₁ (OCH ₂ CH ₂ ) ₂ SO ₃ Na) in a 5 L reaction vessel equipped with a stirrer, temperature sensor, condenser, and nitrogen introducing device A surfactant aqueous solution having mass parts dissolved in 3040 mass parts of ion-exchanged water is charged, and while stirring at a stirring speed of 230 rpm under a nitrogen stream, the internal temperature is raised to 80 ° C., and potassium persulfate (KPS) 10 masses. After adding a polymerization initiator solution in which 400 parts by mass of ion-exchanged water are dissolved and raising the liquid temperature to 75 ° C., 532 parts by mass of styrene, 200 parts by mass of n-butyl acrylate, 68 parts by mass of methacrylic acid And a polymerizable monomer solution consisting of 16.4 parts by mass of n-octyl mercaptan was added dropwise over 1 hour, followed by heating and stirring at 75 ° C. for 2 hours for polymerization (first Polymerization was conducted), the resin particle dispersion containing resin particles (1h) to (1H) was prepared.
The obtained resin particles (1h) had a weight average molecular weight of 16,500.

(B) Second stage polymerization (formation of intermediate layer)
Illustrated as 101.1 parts by weight of styrene, 62.2 parts by weight of n-butyl acrylate, 12.3 parts by weight of methacrylic acid, 1.75 parts by weight of n-octyl mercaptan and a specific benzotriazole compound in a flask equipped with a stirrer Branched paraffin wax isolated from 8 parts by mass of linear paraffin wax (melting point 70 ° C.) and microcrystalline wax as a release agent, charged with a polymerizable monomer solution containing 30 parts by mass of compound (1-2) A monomer solution containing a release agent was prepared by adding 2 parts by mass (melting point: 84 ° C.) and heating the inner temperature to 80 ° C. for dissolution.

On the other hand, a surfactant aqueous solution in which 3 parts by mass of the anionic surfactant used in the first stage polymerization was dissolved in 1560 parts by mass of ion-exchanged water was charged and heated so that the internal temperature became 80 ° C. After adding 32.8 parts by mass (in terms of solid content) of resin particles (1h) obtained in the first-stage polymerization to this surfactant aqueous solution, and further adding a monomer solution containing a release agent An emulsified particle dispersion containing emulsified particles (oil droplets) having a dispersed particle diameter of 340 nm by mixing and dispersing for 8 hours using a mechanical disperser “CLEAMIX” (manufactured by M Technique Co., Ltd.) having a circulation path Was prepared.
Next, a polymerization initiator solution in which 6 parts by mass of potassium persulfate was dissolved in 200 parts by mass of ion-exchanged water was added to this dispersion, and the system was polymerized by heating and stirring at 80 ° C. for 3 hours. Two-stage polymerization) was performed to prepare a resin particle dispersion (1HM) containing resin particles (1 hm).
In addition, the weight average molecular weight of the obtained resin particle (1 hm) was 23000.

(C) Third stage polymerization (formation of outer layer)
A polymerization initiator solution in which 5.45 parts by mass of potassium persulfate was dissolved in 220 parts by mass of ion-exchanged water as a polymerization initiator was added to the resin particle dispersion (1HM) obtained in the second stage polymerization, and 80 ° C. The polymerizable monomer solution consisting of 293.8 parts by mass of styrene, 154.1 parts by mass of n-butyl acrylate and 7.08 parts by mass of n-octyl mercaptan was added dropwise over 1 hour. After completion of the dropwise addition, polymerization (third stage polymerization) was performed by heating and stirring for 2 hours, followed by cooling to 28 ° C. to obtain a resin particle dispersion containing the core part resin particles (1).
The weight average molecular weight of the obtained resin particles for core part (1) was 26800, and the glass transition temperature (Tg) was 28.1 ° C.
In addition, it was 125 nm when the mass mean particle diameter of the resin particle for core parts (1) in this resin particle dispersion was measured.

(3) Preparation Example of Resin Particles for Shell Layer In the first-stage polymerization, 624 parts by mass of styrene, 120 parts by mass of 2-ethylhexyl acrylate, 56 parts by mass of methacrylic acid and n-octyl mercaptan are used as the polymerizable monomer. Polymerization was carried out in the same manner as in the first-stage polymerization except that 16.4 parts by mass were used, thereby obtaining resin particles (1) for shell layer.
The weight average molecular weight of the obtained resin particles for shell layer (1) was 16400, and the glass transition temperature (Tg) was 62.6 ° C.
In addition, it was 95 nm when the mass mean particle diameter of the resin particle (1) for shell layers in this resin particle dispersion was measured.

(4) Preparation Example of Toner Particles (a) Formation of Core Portion Resin particle for core portion (1) 420.7 parts by mass, ion exchange in a reaction vessel equipped with a stirrer, temperature sensor, cooling pipe, and nitrogen introducing device 900 parts by weight of water and 12.9 parts by weight of the colorant fine particle dispersion (1) (in terms of solid content) were stirred and adjusted so that the internal temperature was 30 ° C., and then sodium hydroxide having a concentration of 5 mol / liter. The pH was adjusted to 8 by adding an aqueous solution.
Next, an aqueous solution in which 2 parts by mass of magnesium chloride hexahydrate was dissolved in 1000 parts by mass of ion-exchanged water was added at 30 ° C. over 10 minutes with stirring. After standing for 3 minutes, the temperature was raised and the system was heated to 65 ° C. over 60 minutes. In this state, the average particle diameter of the associated particles was measured with “Coulter Multisizer III” (manufactured by Beckman Coulter), and when the volume-based median diameter became 5.5 μm, 40.2 mass of sodium chloride. An aqueous solution in which 1000 parts by mass of ion-exchanged water is dissolved is added to stop particle growth, and further, fusion is continued by heating and stirring at a liquid temperature of 75 ° C. for 1 hour. A core part-containing liquid (1) containing 1) was obtained.
With respect to the obtained core part (1), the average circularity was measured by using “FPIA2100” (manufactured by Sysmex Corporation), and it was 0.931.

(B) Formation of Shell Layer After adjusting the core part-containing liquid (1) to 65 ° C., 96 parts by mass of resin particles (1) for the shell layer are added, and 2 parts by mass of magnesium chloride hexahydrate is ionized. An aqueous solution dissolved in 1000 parts by mass of exchange water is added over 10 minutes, the temperature is raised to 70 ° C. (shelling temperature), and the mixture is stirred for 1 hour, whereby the shell layer resin is formed on the surface of the core part (1). After fusing the particles (1), a shell layer was formed by performing an aging treatment at a liquid temperature of 75 ° C. for 20 minutes.
Then, after aging treatment (shell layer formation) was stopped by adding 40.2 parts by mass of sodium chloride, the mixture was cooled to 30 ° C. at 6 ° C./min, and the produced particles were filtered. Washing with ion exchange water at 0 ° C. and drying with hot air at 40 ° C. to form toner particles having a shell layer formed on the surface of the core (hereinafter referred to as “toner particles (2)”). Got.

(5) External Addition Treatment The resulting toner particles (2) are subjected to an external addition treatment by the same method as in Toner Production Example 1 to obtain toner (hereinafter referred to as “toner (2)”). Obtained.
The shape and particle size of the toner particles (2) did not change with the addition of the external additive.

[Toner Production Examples 3 to 16 and Comparative Examples 1 to 4]
In toner production example 2, toner particles having a structure in which a shell layer is formed on the surface of the core by the same method as in toner production example 1 except that the compounds shown in Table 1 were used as the specific benzotriazole compounds. (Hereinafter referred to as “toner particles (3)” to “toner particles (16)” and “comparative toner particles (1)” to “comparative toner particles (4)”, respectively).
By subjecting each of the obtained toner particles (3) to toner particles (16) and comparative toner (1) to comparative toner (4) to an external addition treatment in the same manner as in Toner Production Example 1. And toner (hereinafter referred to as “toner (3)” to “toner (16)” and “comparative toner (1)” to “comparative toner (4)”, respectively).
The shapes and particle sizes of the toner particles (3) to the toner particles (16) and the comparative toner (1) to the comparative toner (4) were not changed by the addition of the external additive.

  Here, in Comparative Examples 1 to 4, compounds represented by the following formulas (A) to (D) were used as benzotriazole compounds, respectively.

[Examples 1 to 16 and Comparative Examples 1 to 4]
For each of the toners according to Production Example 1 to Toner Production Example 16 and Comparative Toner Production Example 1 to Comparative Toner Production Example 4 thus obtained, a developer was produced by the following method. Evaluation was performed. The results are shown in Table 1.

(Developer Production Examples 1 to 16 and Comparative Developer Production Examples 1 to 4)
Each of toner (1) to toner (16) and comparative toner (1) to comparative toner (4) is coated with a silicone carrier-coated ferrite carrier having a volume average particle diameter of 60 μm, and the toner concentration is 6 mass%. By mixing so as to obtain developer (1) to developer (16) and comparative developer (1) to comparative developer (4).

<Evaluation of image density stability>
Using an image forming apparatus “bizhub PRO C6500” (manufactured by Konica Minolta Business Technologies, Inc.), image formation was continuously performed 50,000 times in a high temperature and high humidity environment (temperature 33 ° C., relative humidity 80%). Using the reflection densitometer “RD-917” (manufactured by Macbeth Co., Ltd.) for each of the first transfer paper and the 50,000th transfer paper formed, the density of the solid portion of the image formed on the transfer paper Is measured five times, and the difference (image density change amount) between the image density related to the first image and the image density related to the 50,000th image is confirmed, and the change amount of the image density is less than 0.08. If it is good, “◎”, and if the change amount of the image density is 0.08 or more and less than 0.15, “◯” means that there is no practical problem, and the change amount of the image density is 0.15. The case where it was more than was evaluated as "x" as a defect. The results are shown in Table 1.

<Evaluation of light resistance>
Using the image forming apparatus “bizhub PRO C6500” (manufactured by Konica Minolta Business Technologies, Inc.), image formation was performed in a high temperature and high humidity environment (temperature 33 ° C., relative humidity 80%), and the image density of the obtained image was determined. After measurement using a color reflection densitometer “X-Rite 404A” (manufactured by X-Rite), the image was irradiated with light by a xenon fade meter (70000 lux) for 14 days. Thereafter, the image density of the image irradiated with light is measured using a color reflection densitometer “X-Rite 404A” (manufactured by X-Rite), and the difference from the image density before and after the light irradiation (change in image density). The case where the change amount of the image density was 1.0 or less was evaluated as “◯”, assuming that there was no practical problem, and the case where the change amount of the image density exceeded 1.0 was evaluated as “x”. The results are shown in Table 1.

<Evaluation of scratch resistance>
Using the image forming apparatus “bizhub PRO C6500” (manufactured by Konica Minolta Business Technologies, Inc.), image formation is performed in a high temperature and high humidity environment (temperature 33 ° C., relative humidity 80%). After measuring the glossiness (75 degrees) of a black solid part of 1.0 using “Gloss Meter” (manufactured by Murakami Color Engineering Laboratory), a 14000 sandpaper was wrapped around the black solid part of this image. The rubbing treatment was performed by reciprocating a 1 kg weight 5 times. Thereafter, the glossiness (75 degrees) of the image reciprocated with the weight was measured using “Gloss Meter” (manufactured by Murakami Color Engineering Laboratory), and the glossiness change rate was calculated based on the following formula (1). The case where the degree change rate was 80% or more was evaluated as “◯” because there was no practical problem, and the case where the degree of gloss change rate was less than 80% was evaluated as “Poor”. The results are shown in Table 1.

  In this scratch resistance evaluation, in the image formed with the comparative toner, blur stains occurred in the non-image forming portion around the image forming portion. It was confirmed that it was broken and smudged due to this. The image formed with the toner according to the example was also observed with an electron microscope, and it was confirmed that the image was not broken.

<Evaluation of document offset (heat-resistant image storage)>
The image forming apparatus “bizhub PRO C6500” (manufactured by Konica Minolta Business Technologies, Inc.) is loaded with a dedicated finisher “FS-608” (manufactured by Konica Minolta Business Technologies, Inc.), and a transfer paper having a basis weight of 64 g is loaded as a transfer paper. In the default setting, an automatic bookbinding production test of 20 copies of saddle stitch printing (5 sheets per copy) was repeated 50 times under the condition of a pixel rate of 50% per page.
After the produced printed matter is naturally cooled until it reaches room temperature, all the pages are visually confirmed, and evaluation is performed by performing the four-grade grading according to the following evaluation criteria on the page having the largest image defect degree. It was. The results are shown in Table 1.

Rank 1: In the overlapped pages, image defects such as white spots are generated due to the adhesion of the overlapped image forming portions, and clear image transfer occurs in the non-image forming portions. Yes.
Rank 2: Because of the disorder in the paper alignment, for some pages, the edge is cut with the image tilted.
Rank 3: Although a slight resistance (friction) is felt when turning pages, there is no practical problem.
Rank 4: There is no image loss or image transfer in either the image forming unit or the non-image forming unit.

Claims (2)

An electrostatic charge image developing toner containing a resin and a colorant,
An electrostatic image developing toner comprising a compound represented by the following general formula (1):

[Wherein R ¹ represents an alkyl group having a secondary carbon atom or an alkyl group having a tertiary carbon atom, and R ² represents a sulfonic acid group, —SO ₂ NR ⁴ R ⁵ group (where R ⁴ and R ⁵ each independently represents a hydrogen atom, an alkyl group or an aryl group.) Or —SO ₂ OR ⁶ group (where R ⁶ represents an aliphatic hydrocarbon group, an aromatic hydrocarbon group or a heterocyclic ring) Group). R ³ represents a hydrogen atom or a chlorine atom. ]   The mold release agent according to claim 1, comprising a mold release agent, wherein the mold release agent is a mixture of a branched paraffin compound and a linear paraffin compound, and has an endothermic peak in the range of 60 to 105 ° C. The toner for developing an electrostatic image according to the description.