JP2010145673A - Toner for image formation, single-component developer or two-component developer having the toner, and image forming method, image forming apparatus and process cartridge using the toner - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a toner for image formation, the toner achieving both of low temperature fixability and heat-resistant storage properties having gloss, even in high-speed fixing and no offset phenomenon, and to provide an image forming method and apparatus, and a process cartridge. <P>SOLUTION: The toner is prepared by compounding a colorant and a binder resin, and release agent by 3 to 8 parts, with respect to 100 parts of the binder resin, and subjecting the compounded material to a melt-kneading step, followed by pulverizing and classifying steps. The release agent shows a permeation amount of 15 mm to 30 mm calculated by an evaluation method, as described in the following section. The evaluation method for a permeation amount includes charging a glass container (having a diameter of about 35 mm and a volume of 50 ml) with 6 g of the toner; heating the toner for one hour at a temperature where the release agent fuses fully; dipping one end of a rectangular sheet (in a size of 1 cm×10 cm), prepared by cutting a copy sheet T6000 manufactured by RICOH, in the fused toner and keeping for 2 hours; and then measuring, by visual observation, the infiltration height L0 (mm) and the infiltration height Lt (mm) of the toner release agent and the toner, respectively; and calculating a permeation amount L (mm) defined by L(mm)=L0(mm)-Lt(mm). <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an electrophotographic toner, and more specifically, an image forming toner used in an image forming apparatus using a so-called electrophotographic method, such as an electrostatic copying machine or a laser beam printer, and a one-component developer thereof. The present invention relates to a two-component developer, an image forming method using an image forming toner, an image forming apparatus, and a process cartridge.

  Since the number of output sheets per unit time required for the image forming apparatus is increasing year by year, further speeding is desired. As this speed increases, technically more severe conditions are required. In particular, in recent years when electrophotographic systems are being used for on-demand digital printing, it is necessary to further widen the temperature range in which no offset occurs while maintaining high gloss.

  However, since the thermal energy per unit time (nip time) that can be supplied to the image forming toner with the increase in speed becomes smaller than in the past, sufficient heat is not transmitted to the image forming toner, and the recording medium An image forming toner existing on or near the surface is poorly melted.

  When a fusing failure of the image forming toner occurs during fixing, the image forming toner layer on the recording medium is cut at a location where the fusing failure occurs due to insufficient viscosity, one remaining on the recording medium and the other Adheres to the fixing roller. Alternatively, since the melting defect occurs, the adhesion between the recording medium and the image forming toner is insufficient, and all the image forming toner on the recording medium adheres to the fixing roller. The toner adhering to the roller portion of the fixing roller is fixed to a place other than the desired location as in the case of the offset described above, causing a ghost image or the like. That is, when the heating is not sufficient, an offset phenomenon, a so-called cold offset phenomenon occurs, which is a problem.

  In addition, poor melting of the image forming toner during fixing is a problem because even if the cold offset phenomenon does not occur, the image quality of the output image is deteriorated such that the glossiness is significantly reduced. .

Therefore, in order to solve these problems related to poor melting, an image forming toner containing a resin having a low softening point (melting point), a release agent, a fixing auxiliary agent, etc. for the purpose of fixing at a lower temperature. R & D has been vigorously done.
For example, the applicant of the present application first focused on the endothermic peak of the toner and specified the difference between the maximum endothermic peak before and after the heat treatment of the toner (40 ° C. × 72 hours) (see, for example, Patent Document 1), or By prescribing the FTIR spectral ratio of the crystalline polyester resin before and after isothermal storage of the toner containing the crystalline polyester resin as a raw material (45 ° C. × 12 hours) (see, for example, Patent Document 2), A method to improve low-temperature fixability, heat-resistant storage stability and offset resistance was proposed.
In addition, by defining the dispersion diameter of the colorant and the dispersion diameter of the release agent, and by defining the charge amount (charge rising ratio) of the toner, color reproducibility, offset resistance, and charging can be achieved at a high toner image density. A method for improving the rising characteristics has been proposed (see, for example, Patent Document 3).

  However, image forming toners excellent in low-temperature fixability generally have a problem related to heat-resistant storage stability in which the storage stability in a high-temperature environment is reduced and solidified. That is, in the image forming toner, there is a trade-off relationship between low-temperature fixability and heat-resistant storage stability. In other words, as the speed of the image forming apparatus increases, it is required to fix the image forming toner with lower thermal energy. However, the image forming toner having excellent low temperature fixability has sufficient heat-resistant storage stability. In addition, it is difficult and difficult to handle during storage and transportation in a high temperature environment. On the other hand, an image forming toner having excellent heat-resistant storage stability does not have sufficient low-temperature fixability and causes image quality problems such as a cold offset phenomenon.

JP 2007-72333 A JP 2007-206097 A Japanese Patent No. 3478963

  The present invention has been made in view of the problems in the prior art described above, and can be applied to an electrophotographic image forming apparatus capable of high-speed output without causing an offset phenomenon while maintaining gloss. An object of the present invention is to provide an image forming toner, a one-component developer and a two-component developer thereof, which are fixed only at a desired position on a recording medium and have excellent low-temperature fixability and heat-resistant storage stability. It is another object of the present invention to provide an image forming method, an image forming apparatus, and a process cartridge using the image forming toner.

  As a result of intensive studies, the present inventors have found that the above problems can be solved by the inventions described in the following [1] to [11], and have reached the present invention. Hereinafter, the present invention will be specifically described.

[1]: The above problem is in an image forming toner in which a compound containing at least a colorant, a binder resin, and a release agent is pulverized and classified after passing through a melting and kneading step.
The release agent is blended in the range of 3 to 8 parts by weight with respect to 100 parts by weight of the binder resin, and the penetration amount of the release agent calculated by the following evaluation method is 15 mm to 30 mm. This is solved by the characteristic image forming toner.
[Method of evaluating penetration of release agent]
Into a glass container having a diameter of about 35 mm and a capacity of 50 ml, 6 g of the image forming toner is charged, heated to a temperature at which the release agent is sufficiently melted, and heated for 1 hour. One end of a strip-shaped paper (the longitudinal direction of the strip shape is a horizontal direction) obtained by cutting Ricoh Co. copy paper T6000 (A4 horizontal side) into 1 cm × 10 cm is immersed in the melted toner, and after maintaining for 2 hours, visually Observed height L0 (mm) where the release agent soaked from one end (bottom side) of the strip-shaped paper and height Lt (mm) where the toner soaked from one end (bottom side) of the strip-shaped paper, respectively. Measure and calculate the permeation amount L (mm) of the release agent from the following equation. L (mm) = L0 (mm) -Lt (mm)

  [2]: The image forming toner according to [1], wherein the release agent is a ketone wax or diglyceryl tetrastearate.

  [3]: In the image forming toner described in [1] or [2] above, the binder resin is mainly composed of a polyester resin.

  [4]: The image forming toner according to any one of [1] to [3], wherein the toner has a weight average particle diameter of 3.5 μm to 10 μm.

  [5]: The above problem is solved by a one-component developer comprising the image forming toner according to any one of [1] to [3].

  [6]: The above problem is solved by a two-component developer comprising the image forming toner according to any one of [1] to [3] and a carrier.

[7]: The above-described problems include a charging step for charging at least the surface of the image carrier, an electrostatic latent image forming step for forming an electrostatic latent image on the image carrier, and the electrostatic latent image for image formation. A development process for forming a visible image by developing with toner, a transfer process for transferring the visible image onto a recording medium to form an unfixed image, and fixing the unfixed image on the recording medium An image forming method comprising: a fixing step
The image forming toner used for forming the visible image is the image forming toner described in any one of [1] to [4].

  [8]: In the image forming method described in [7], the recording medium conveyance speed in the fixing step is 280 mm / second or more.

[9]: The above-described problems include at least an image carrier, a charging unit that charges the surface of the image carrier, an exposure unit that exposes the charged image carrier surface to form an electrostatic latent image, and A developing unit that develops an electrostatic latent image using image forming toner to form a visible image; a transfer unit that transfers the developed toner image onto a recording medium to form an unfixed image; and An image forming apparatus comprising a fixing unit that fixes an unfixed image on the recording medium,
The image forming toner used for forming the visible image is the image forming toner according to any one of [1] to [4].

  [10]: In the image forming apparatus described in [9], a recording medium conveyance speed during fixing by the fixing unit is 280 mm / second or more.

[11]: The above problem is solved by an image carrier,
A charging unit that charges the surface of the image carrier, an exposure unit that exposes the charged image carrier surface to form an electrostatic latent image, and develops the formed electrostatic latent image using image forming toner. At least one means selected from developing means, transfer means for transferring the developed toner image to a recording medium, and cleaning means for removing toner remaining on the surface of the image carrier after transfer;
Is a process cartridge that can be attached to and detached from the integrated image forming apparatus body,
The image forming toner to be used is the image forming toner according to any one of [1] to [4].

According to the image forming toner of the present invention and its one-component developer and two-component developer, glossiness is maintained even at high-speed output in an electrophotographic image forming apparatus, and offset phenomenon (cold offset and hot offset). The toner is fixed only at a desired position on the recording medium without occurrence of the toner, and has excellent low-temperature fixability and heat-resistant storage stability.
According to the image forming method of the present invention, since the image forming toner having both the low-temperature fixability and the heat-resistant storage stability and having the excellent glossiness and offset resistance is used, the image forming apparatus of the electrophotographic system having a high output can be used. Even when an image is formed, it is possible to stably output a high-quality image without generating a ghost or the like.
According to the image forming apparatus of the present invention, since the image forming toner having both the low temperature fixing property and the heat resistant storage stability and having the excellent glossiness and offset resistance is used, an abnormal image is generated even if the process linear velocity is high. A stable image can be output.
The image forming method and the image forming apparatus of the present invention can be widely applied to electrophotographic application fields using electrophotography (for example, electrostatic copying machines, laser beam printers, etc.).
In the process cartridge of the present invention, since the image forming toner of the present invention is supplied from the developing unit, the fixing unit is stably fixed only at a desired position on the recording medium without causing an offset phenomenon due to an unfixed image. High quality images can be output. In addition, maintenance management and handling are easy.

As described above, the image forming toner according to the present invention is an image forming toner obtained by pulverizing and classifying a compound containing at least a colorant, a binder resin, and a release agent after a melting and kneading step.
The release agent is blended in the range of 3 to 8 parts by weight with respect to 100 parts by weight of the binder resin, and the penetration amount of the release agent calculated by the following evaluation method is 15 mm to 30 mm. It is a feature.
[Method of evaluating penetration of release agent]
Into a glass container having a diameter of about 35 mm and a capacity of 50 ml, 6 g of the image forming toner is charged, heated to a temperature at which the release agent is sufficiently melted, and heated for 1 hour. One end of a strip-shaped paper (the longitudinal direction of the strip shape is a horizontal direction) obtained by cutting Ricoh Co. copy paper T6000 (A4 horizontal side) into 1 cm × 10 cm is immersed in the melted toner, and after maintaining for 2 hours, visually Observed height L0 (mm) where the release agent soaked from one end (bottom side) of the strip-shaped paper and height Lt (mm) where the toner soaked from one end (bottom side) of the strip-shaped paper, respectively. Measure (for example, using calipers), and calculate the permeation amount L (mm) of the release agent from the following equation.
L (mm) = L0 (mm) -Lt (mm)

  Hereinafter, the image forming toner according to the present invention, its one-component developer or two-component developer, and an image forming method, an image forming apparatus, and a process cartridge using the image forming toner will be described in detail with specific examples. However, the present invention is not limited to these.

The temperature at which the release agent is sufficiently melted in the method for evaluating the amount of penetration of the release agent is not particularly limited. For example, it may be 140 ° C. or 160 ° C.
However, a release agent that does not melt even at 160 ° C., which is considered to be close to the fixing temperature of a general copying machine, does not sufficiently dissolve even at the time of heat fixing, and therefore cannot exert a toner release effect. In addition, a release agent that actively vaporizes even at 160 ° C. may adversely affect developability, such as a decrease in charge due to spent on the developer. Accordingly, in the present invention, about 160 ° C. is preferable as the evaluation temperature of the release agent that is less likely to cause various problems.
The melting point of the release agent can be measured using a TG-DSC system (TAS-100) manufactured by Rigaku Corporation.

The permeability is greatly influenced not only by the type of the release agent but also by the combination with the binder resin. This is because the state of presence of the release agent in the toner differs depending on the compatibility between the release agent and the resin. When the compatibility is high, the release agent is difficult to dissolve from the toner, and the paper does not ooze out actively, so the minimum fixing temperature becomes high. On the other hand, when the compatibility is low, exudation is actively performed, and the minimum fixing temperature is lowered. Therefore, even if the same release agent is used, for example, the exudation of the release agent A when using the resin A is high, and the exudation becomes low when using the resin B, so that the minimum fixing temperature is lowered. Phenomenon occurs. For this reason, as a result of considering paying attention to the need to evaluate the effect on the fixing property of the release agent in consideration of the combination with the resin, the present invention has been achieved.
That is, in an image forming toner in which a compound containing at least a colorant, a binder resin, and a release agent is subjected to a melting and kneading step and then pulverized and classified, the compounding ratio of the release agent to the binder resin, If the penetration amount of the release agent calculated by the evaluation method is defined, the present invention can be satisfied without being particularly limited to the type of resin and release agent used for the image forming toner.

In the present invention, the amount (penetration amount) of the release agent in the image forming toner (hereinafter sometimes abbreviated as “toner”) soaks into the strip-shaped paper within a predetermined time is from 15 mm to 30 mm. Stipulated in
This is because the speed at which the release agent finely dispersed in the toner penetrates into the paper of the base material greatly affects the fixing property of the toner. Therefore, if the thickness is less than 15 mm, the release agent eluted from the toner has less penetration into the paper substrate, so fixing at a low temperature has insufficient binding force with the substrate, and cold offset occurs. Cause.
If it exceeds 30 mm, the mechanism is not clear, but the release agent oozing out from the toner is likely to be interposed between the melted toner and the paper (there is a release agent between the fixing roller and the toner). In this state, the binding force between the toner and the paper is insufficient, and it is assumed that a cold offset occurs.

Further, the blending amount of the release agent in the present invention is in the range of 3 to 8 parts by weight with respect to 100 parts by weight of the binder resin.
That is, when the amount is less than 3 parts, the amount of the release agent that can be eluted from the toner is reduced, so that the effect of releasing from the base material is not sufficiently exhibited in fixing at a high temperature, causing hot offset. In addition, when more than 8 parts are added, the mechanism is not clear, but the release agent exuded from the toner tends to be interposed between the molten toner and the paper (between the fixing roller and the toner). In such a state that a release agent is present in the toner), the binding force between the toner and the paper becomes insufficient, causing a cold offset.
Further, when the blending agent containing the colorant, binder resin and release agent used as the image forming toner of the present invention is melted and kneaded, the binder is added when the amount of the release agent having a low viscosity is large. The mixed state with the resin becomes poor, and the release agent is dispersed with coarse particles in the resin. Especially in the case of two-component development, it may cause adverse effects such as spent on the carrier. Since it may be a cause, it is not preferable.

As described above, the compounding ratio of the release agent to the binder resin (in the range of 3 to 8 parts by weight with respect to 100 parts by weight of the binder resin) and the penetration amount of the release agent calculated by the evaluation method (15 mm) Since the present invention can be satisfied if it is defined as 30 mm or less), the release agent is not particularly limited as long as it satisfies these conditions.
As the release agent component, waxes and waxes (natural wax, synthetic wax, etc.) can be used. Examples of natural waxes include plant waxes, mineral waxes, and petroleum waxes.
Further, fatty acid amides such as 12-hydroxystearic acid amide, stearic acid amide, phthalic anhydride imide, chlorinated hydrocarbon, and poly-n-stearyl methacrylate, poly-n-, which are low molecular weight crystalline polymer resins A crystalline polymer having a long alkyl group in the side chain such as a homopolymer or copolymer of polyacrylate such as lauryl methacrylate (for example, a copolymer of n-stearyl acrylate-ethyl methacrylate, etc.) can also be used. .
Particularly preferred examples include ketone wax and diglyceryl tetrastearate.

As in the case of the release agent, the compounding ratio of the binder resin to the release agent (100 parts by weight of the binder resin with respect to 3 to 8 parts by weight of the release agent) and the release calculated by the evaluation method described above. If the penetration amount of the agent (15 mm or more and 30 mm or less) is defined, the present invention can be satisfied, so that the binder resin satisfying these conditions is not particularly limited.
As the binder resin used in the present invention, all those conventionally used for image forming toners can be used. For example, homopolymers of styrene such as polystyrene, polychlorostyrene, and polyvinyltoluene, and substituted products thereof; styrene / p-chlorostyrene copolymer, styrene / propylene copolymer, styrene / vinyltoluene copolymer, styrene / vinyl Naphthalene copolymer, styrene / methyl acrylate copolymer, styrene / ethyl acrylate copolymer, styrene / butyl acrylate copolymer, styrene / octyl acrylate copolymer, styrene / methyl methacrylate copolymer, Styrene / ethyl methacrylate copolymer, styrene / butyl methacrylate copolymer, styrene / α-chloromethyl methacrylate copolymer, styrene / acrylonitrile copolymer, styrene / vinyl ethyl ether copolymer, styrene / vinyl methyl Ketone copolymer, steel Styrene copolymers such as styrene / butadiene copolymer, styrene / isoprene copolymer, styrene / acrylonitrile / indene copolymer, styrene / maleic acid copolymer, styrene / maleic acid ester copolymer; polymethyl methacrylate , Polybutyl methacrylate, polyvinyl chloride, polyvinyl acetate, polyethylene, polypropylene, polyester, polyvinyl butyl butyral, polyacrylic acid resin, rosin, modified rosin, terpene resin, phenol resin, aliphatic or alicyclic hydrocarbon resin, aromatic A group petroleum resin, chlorinated paraffin, paraffin wax and the like can be mentioned, and these are used alone or in admixture of two or more.

In the image forming toner according to the present invention, among the enumerated above, it is preferable to use a polyester resin as a binder resin because of excellent low-temperature fixability.
In addition, since the image needs to be glossy, the molecular weight of the binder resin is relatively small. In the case of a polyester resin, the resin strength can be easily obtained even if the molecular weight is small, and the toner is finely pulverized while stirring the toner. It is less likely to aggregate or agglomerate, and is more advantageous than a general vinyl polymer resin for toner.

In the image forming toner of the present invention, in order to achieve both low-temperature fixability and heat-resistant storage stability and appropriate gloss (glossiness), the weight average molecular weight (Mw) of the resin (for example, polyester resin) in the toner is 1000. It is desirable to be about ˜500000. Note that the number average molecular weight (Mn) may be measured instead of the weight average molecular weight.
The weight average molecular weight (Mw) or the number average molecular weight (Mn) can be measured as follows.
[Measurement of weight average molecular weight (Mw)]
The mass average molecular weight of the binder resin is measured by GPC (gel permeation chromatography) under the following conditions.
・ Apparatus: GPC-150C (manufactured by Waters)
Column: KF801-807 (manufactured by Shodex)
・ Temperature: 40 ℃
・ Solvent: THF (tetrahydrofuran)
・ Flow rate: 1.0 mL / min ・ Sample: 0.1 mL injection of a sample with a concentration of 0.05 to 0.6% Molecular weight created from a monodisperse polystyrene standard sample from the molecular weight distribution of the binder resin measured under the above conditions The mass average molecular weight of the binder resin is calculated using the calibration curve.
[Measurement of Number Average Molecular Weight (Mn)]
The number average molecular weight of the binder resin is measured by GPC under the following conditions.
・ Apparatus: GPC-150C (manufactured by Waters)
Column: KF801-807 (manufactured by Shodex)
・ Temperature: 40 ℃
・ Solvent: THF (tetrahydrofuran)
Flow rate: 1.0 mL / min Sample: Inject 0.1 mL of a sample having a concentration of 0.05 to 0.6%.
Further, when the insoluble content when 1 g of a sample (binder resin) is added to 100 ml of THF is 75% by weight or more, DMF (dimethylformamide) is used as a solvent. The number average molecular weight is calculated from a molecular weight calibration curve prepared using a monodisperse polystyrene standard sample.

Examples of the monomer constituting the polyester resin include, but are not limited to, the following.
Examples of the divalent alcohol component include ethylene glycol, propylene glycol, 1,3-butanediol, 1,4-butanediol, 2,3-butanediol, diethylene glycol, triethylene glycol, 1,5-pentanediol, 1 , 6-hexanediol, neopentyl glycol, 2-ethyl-1,3-hexanediol, hydrogenated bisphenol A, diol obtained by polymerizing cyclic ethers such as ethylene oxide and propylene oxide to bisphenol A, and the like. Can be mentioned.

  In order to crosslink the polyester resin, it is preferable to use a trivalent or higher alcohol together. Examples of the trihydric or higher polyhydric alcohol include sorbitol, 1,2,3,6-hexanetetrol, 1,4-sorbitan, pentaerythritol, such as dipentaerythritol, tripentaerythritol, 1,2,4- Butanetriol, 1,2,5-pentatriol, glycerol, 2-methylpropanetriol, 2-methyl-1,2,4-butanetriol, trimethylolethane, trimethylolpropane, 1,3,5-trihydroxybenzene , Etc.

Examples of acid components that form polyester polymers include benzene dicarboxylic acids such as phthalic acid, isophthalic acid, and terephthalic acid, or anhydrides thereof, alkyl dicarboxylic acids such as succinic acid, adipic acid, sebacic acid, and azelaic acid, or the like. Unsaturated dibasic acids such as anhydride, maleic acid, citraconic acid, itaconic acid, alkenyl succinic acid, fumaric acid, mesaconic acid, maleic anhydride, citraconic anhydride, itaconic anhydride, alkenyl succinic anhydride, etc. Unsaturated dibasic acid anhydrides, and the like.
Trivalent or higher polyvalent carboxylic acid components include trimet acid, pyrometic acid, 1,2,4-benzenetricarboxylic acid, 1,2,5-benzenetricarboxylic acid, 2,5,7-naphthalenetricarboxylic acid, 1 , 2,4-Naphthalenetricarboxylic acid, 1,2,4-butanetricarboxylic acid, 1,2,5-hexanetricarboxylic acid, 1,3-dicarboxy-2-methyl-2-methylenecarboxypropane, tetra (methylenecarboxy ) Methane, 1,2,7,8-octanetetracarboxylic acid, emporic trimer acid, or their anhydrides, partially lower alkyl esters, and the like.

The glass transition temperature (Tg) of the polyester resin preferably used in the present invention is desirably low as long as the heat resistant storage stability of the toner is not deteriorated. In general, the Tg is 40 to 70 ° C., preferably 60 to 70 ° C. 65 ° C. When Tg is higher than the above range, the lower limit fixing temperature of the toner is increased, so that the low temperature fixing property of the toner is deteriorated.
The glass transition temperature (Tg) was measured using a TG-DSC system (TAS-100) manufactured by Rigaku Corporation in the same manner as the toner Tg described later.

  As the binder resin that can be used in the toner of the present invention, a polyester resin component containing a vinyl polymer component can also be used. In this case, a resin containing a monomer component capable of reacting with both of these resin components may be used in at least one of the vinyl polymer component and the polyester resin component. Examples of monomers that can react with the vinyl polymer among the monomers constituting the polyester resin component include unsaturated dicarboxylic acids such as phthalic acid, maleic acid, citraconic acid, and itaconic acid, or anhydrides thereof. Examples of the monomer constituting the vinyl polymer component include those having a carboxyl group or a hydroxy group, and acrylic acid or methacrylic acid esters.

As the colorant used in the image forming toner of the present invention, all known dyes and pigments can be used.
For example, carbon black, nigrosine dye, iron black, naphthol yellow S, Hansa yellow (10G, 5G, G), cadmium yellow, yellow iron oxide, ocher, yellow lead, titanium yellow, polyazo yellow, oil yellow, Hansa Yellow (GR, A, RN, R), Pigment Yellow L, Benzidine Yellow (G, GR), Permanent Yellow (NCG), Vulcan Fast Yellow (5G, R), Tartrazine Lake, Quinoline Yellow Lake, Anthrazan Yellow BGL , Isoindolinone yellow, bengara, red lead, red lead, cadmium red, cadmium mercury red, antimony red, permanent red 4R, para red, phise red, parachlor ortho nitroaniline red, risor fast scarlet G, Reliant Fast Scarlet, Brilliant Carmin BS, Permanent Red (F2R, F4R, FRL, FRLL, F4RH), Fast Scarlet VD, Belkan Fast Rubin B, Brilliant Scarlet G, Resol Rubin GX, Permanent Red F5R, Brilliant Carmine 6B, Pogment Scarlet 3B, Bordeaux 5B, Toluidine Maroon, Permanent Bordeaux F2K, Helio Bordeaux BL, Bordeaux 10B, Bon Maroon Light, Bon Maroon Medium, Eosin Lake, Rhodamine Lake B, Rhodamine Lake Y, Alizarin Lake, Thioindigo Red B, Thioindigo Maroon, oil red, quinacridone red, pyrazolone red, polyazo red, chrome vermilion, benzidine Range, Perinone Orange, Oil Orange, Cobalt Blue, Cerulean Blue, Alkaline Blue Lake, Peacock Blue Lake, Victoria Blue Lake, Metal Free Phthalocyanine Blue, Phthalocyanine Blue, Fast Sky Blue, Indanthrene Blue (RS, BC), Indigo , Ultramarine, bitumen, anthraquinone blue, fast violet B, methyl violet lake, cobalt purple, manganese purple, dioxane violet, anthraquinone violet, chrome green, zinc green, chromium oxide, pyridiane, emerald green, pigment green B, naphthol green B, Green Gold, Acid Green Lake, Malachite Green Lake, Phthalocyanine Green, Anthraquinone Green, Oxidized Chi Tan, zinc white, litbon and mixtures thereof.
The content of the colorant is usually 1 to 15% by weight, preferably 3 to 10% by weight, based on the image forming toner.

  The image forming toner according to the present invention may contain a charge control agent, a magnetic powder, an external additive, and the like as required, as long as the effects of the present invention are not impaired.

(Charge control agent)
As the charge control agent used in the present invention, any conventionally known charge control agent can be used. For example, nigrosine dyes, triphenylmethane dyes, chromium-containing metal complex dyes, molybdate chelate pigments, rhodamine dyes, alkoxy amines, quaternary ammonium salts (including fluorine-modified quaternary ammonium salts), alkylamides, phosphorus Simple substance or compound, tungsten simple substance or compound, fluorine-based activator, salicylic acid metal salt, metal salt of salicylic acid derivative, and the like.
Specifically, Bontron 03 of a nigrosine dye, Bontron P-51 of a quaternary ammonium salt, Bontron S-34 of a metal-containing azo dye, E-82 of an oxynaphthoic acid metal complex, E-84 of a salicylic acid metal complex , Phenolic condensate E-89 (above, Orient Chemical Industries, Ltd.), quaternary ammonium salt molybdenum complex TP-302, TP-415 (above, Hodogaya Chemical Co., Ltd.), quaternary ammonium salt copy Charge PSY VP2038, copy blue PR of triphenylmethane derivative, copy charge of quaternary ammonium salt NEG VP2036, copy charge NX VP434 (manufactured by Hoechst), LRA-901, LR-147 which is a boron complex (Nippon Carlit) Manufactured), copper phthalocyanine, perylene, quinacridone, azo series Fee, a sulfonic acid group, a carboxyl group, and polymer compounds having a functional group such as quaternary ammonium salts.
The content of the charge control agent is appropriately determined according to desired charging characteristics.

(External additive)
As the external additive used in the present invention, inorganic fine particles are preferably used for the purpose of imparting fluidity, chargeability and developability. The primary particle diameter of the inorganic fine particles is preferably 5 × 10 ^-3 ~2μm, it is particularly preferably 5 × 10 ^-3 ~0.5μm. Moreover, it is preferable that the specific surface area by BET method is 20-500 m < ² > / g. The amount of the inorganic fine particles added is preferably 0.01 to 5 wt% of the image forming toner.
Specific examples of the inorganic fine particles include, for example, silica, alumina, titanium oxide, barium titanate, magnesium titanate, calcium titanate, strontium titanate, zinc oxide, tin oxide, silica sand, clay, mica, wollastonite, Examples thereof include diatomaceous earth, chromium oxide, cerium oxide, bengara, antimony trioxide, magnesium oxide, zirconium oxide, barium sulfate, barium carbonate, calcium carbonate, silicon carbide, and silicon nitride.

  Such external additives can be surface treated to increase hydrophobicity and prevent deterioration of flow characteristics and charging characteristics even under high humidity. For example, silane coupling agents, silylating agents, silane coupling agents having an alkyl fluoride group, organic titanate coupling agents, aluminum coupling agents, silicone oils, modified silicone oils and the like are preferable surface treatment agents. .

The weight average particle diameter of the toner is not particularly limited and can be appropriately selected according to the purpose. However, in order to obtain a high-quality image with excellent granularity, sharpness, and fine line reproducibility, the weight average particle diameter Is preferably 3.5 μm to 10 μm. The smaller the particle size, the better the image sharpness and fine line reproducibility. In particular, in a color image forming apparatus, the demand for image quality is strict and toner of 10 μm or less is required. In particular, 7.5 μm or less is preferable for image quality. On the other hand, if the toner particle size becomes too small, the fluidity and transferability of the toner deteriorate. Here, the weight average particle diameter of the toner can be obtained as follows.
As an apparatus for measuring the particle size distribution of toner particles by the Coulter counter method, there are Coulter Counter TA-II and Coulter Multisizer II (both manufactured by Coulter). In the present invention, measurement was performed using Coulter Multisizer II. The measurement method is described below.

[Weight average particle diameter (Dw) of toner]
First, 0.1 to 5 ml of a surfactant, preferably polyoxyethylene alkyl ether, is added as a dispersant to 100 to 150 ml of an electrolytic aqueous solution. Here, the electrolytic solution is prepared by preparing an about 1% NaCl aqueous solution using primary sodium chloride, and for example, ISOTON-II (manufactured by Coulter) can be used. Here, 2 to 20 mg of a measurement sample is further added. The electrolytic solution in which the sample is suspended is subjected to a dispersion treatment with an ultrasonic disperser for about 1 to 3 minutes, and the measurement device is used to measure the volume and number of toner particles or toner using a 100 μm aperture as an aperture. Volume distribution and number distribution are calculated. From the obtained distribution, the weight average particle diameter (Dw) and the number average particle diameter (Dn) of the toner can be obtained.

  The channel in the above measurement is as follows: 2.00 to less than 2.52 μm; 2.52 to less than 3.17 μm; 3.17 to less than 4.00 μm; 4.00 to less than 5.04 μm; 5.04 to 6.35 μm Less than 6.35 to less than 8.00 μm; less than 8.00 to less than 10.08 μm; less than 10.08 to less than 12.70 μm; less than 12.70 to less than 16.00 μm; less than 16.00 to less than 20.20 μm; ≦ 25.40 μm; 25.40 to less than 32.00 μm; 13 channels of 32.00 to less than 40.30 μm are used, and particles having a particle diameter of 2.00 μm to less than 40.30 μm are targeted.

The Tg of the image forming toner of the present invention is preferably 60 to 65 ° C. When Tg is higher than the above range, the lower limit fixing temperature of the toner is increased, so that the low temperature fixing property of the toner is deteriorated.
The Tg (DSC maximum endothermic peak) of the toner for image formation is tangent to the endothermic curve near the melting point using a TG-DSC system (TAS-100) manufactured by Rigaku Corporation and using an analysis system in the TAS-100 system. And calculated from the point of contact with the baseline.
That is, about 10 mg of a toner sample is placed in an aluminum sample container, which is placed on a holder unit and set in an electric furnace. Heating was performed from room temperature to 180 ° C. at a heating rate of 10 ° C./min, and calculation was performed based on the obtained endothermic curve.

The image forming toner of the present invention can be used as a one-component developer or a two-component developer. That is, the one-component developer is composed of only the image forming toner, and the two-component developer is composed of the image forming toner and the carrier.
[One-component developer]
In the one-component developer, it can be used as a non-magnetic one-component toner or a magnetic one-component toner (magnetic toner).
When used as a magnetic toner, a known magnetic material can be used. That is, magnetic materials contained in the magnetic toner include iron oxides such as magnetite, hematite, and ferrite, metals such as iron, cobalt, and nickel, or aluminum, cobalt, copper, lead, magnesium, tin, and the like of these metals. Examples include alloys of metals such as zinc, antimony, beryllium, bismuth, cadmium, calcium, manganese, selenium, titanium, tungsten, vanadium, and mixtures thereof. These ferromagnetic materials desirably have an average particle size of about 0.1 to 2 μm. The amount of the ferromagnetic material contained in the toner is 20 to 200 parts by weight, particularly preferably 100 parts by weight of the resin component, with respect to 100 parts by weight of the binder resin. 40 to 150 parts by weight per part.

[Two-component developer]
As the carrier used in the two-component developer of the present invention, conventionally known ones for two-component developers can be used.
For example, a carrier made of magnetic particles such as iron or ferrite, a resin-coated carrier in which such magnetic particles are coated with a resin, or a binder-type carrier in which magnetic fine powder is dispersed in a binder resin. Can be used.
Magnetic materials include iron oxides such as magnetite, hematite, and ferrite, metals such as iron, cobalt, and nickel, or aluminum, cobalt, copper, lead, magnesium, tin, zinc, antimony, beryllium, bismuth, cadmium, Metal alloys such as calcium, manganese, selenium, titanium, tungsten, vanadium and mixtures thereof can be used.

Among these carriers, a silicone resin, a copolymer resin (graft resin) of an organopolysiloxane and a vinyl monomer, or a resin-coated carrier using a polyester resin can be used as a coating resin, such as toner spent. A carrier coated with a resin obtained by reacting an isocyanate with a copolymer resin of an organopolysiloxane and a vinyl monomer is preferable from the viewpoint of durability, environmental stability, and spent resistance. .
As the vinyl monomer, it is necessary to use a monomer having a substituent such as a hydroxyl group reactive with isocyanate. In addition, it is preferable to use a magnetic carrier having a volume average particle diameter of 20 to 100 μm, preferably 20 to 60 μm from the viewpoint of ensuring high image quality and preventing carrier fogging.

  In addition to the above, examples of carrier coating materials used for carriers include amino resins such as urea-formaldehyde resins, melamine resins, benzoguanamine resins, urea resins, polyamide resins, and epoxy resins. Polyvinyl resins and polyvinylidene resins, acrylic resins, polymethyl methacrylate resins, polyacrylonitrile resins, polyvinyl acetate resins, polyvinyl alcohol resins, polyvinyl butyral resins, polystyrene resins and styrene-acrylic copolymer resins, Halogenated olefin resins such as vinyl chloride, polyester resins such as polyethylene terephthalate resin and polybutylene terephthalate resin, polycarbonate resins, polyethylene resins, polyvinyl fluoride resins, polyvinylidene fluoride resins, polytrifluoroethylene resins, polyhexafluoropropylene Resin, copolymer of vinylidene fluoride and acrylic monomer, copolymer of vinylidene fluoride and vinyl fluoride, tetrafluoroethylene and fluoride Vinylidene fluoro such as terpolymers of non-fluorinated monomer, and silicone resins.

  Moreover, you may make conductive powder etc. contain as a filler in coating resin as needed. As the conductive powder, metal powder, carbon black, titanium oxide, tin oxide, zinc oxide, aluminum oxide, silica and the like can be used. These preferably have an average particle diameter of 1 μm or less. When the average particle diameter is larger than 1 μm, it is difficult to control electric resistance in the case of conductive powder.

The toner for image formation according to the present invention is obtained by pulverizing and classifying a compound containing at least a colorant, a binder resin, and a release agent through a melting and kneading step. explain. The image forming toner of the present invention is not limited to this.
As a method for producing the image forming toner according to the present invention, first, the binder resin described above, a pigment or dye as a colorant, a release agent, and, if necessary, a charge control agent and other additives are added. The blend containing is thoroughly mixed with a mixer such as a Henschel mixer. The blended mixture is converted into a continuous twin screw extruder (for example, KTK type twin screw extruder manufactured by Kobe Steel, TEM type twin screw extruder manufactured by Toshiba Machine Co., Ltd., PCM type twin screw extruder manufactured by Ikekai Tekko Co., Ltd.) The components are often kneaded using a thermal kneader such as a KEX type twin screw extruder manufactured by Kurimoto Iron Works Co., Ltd. or a continuous single screw kneader (eg, Kneader manufactured by Buss Co., Ltd. or KCK kneader). To do. At this time, as a method for increasing the specific energy, a method of decreasing the kneading amount or a method of lowering the kneader setting temperature and kneading the kneaded material in a high viscosity state is used.
Next, after cooling the kneaded product, it is coarsely pulverized using a hammer mill or the like, and further pulverized by a fine pulverizer or mechanical pulverizer using a jet stream, and a classifier using a swirling air stream or the Coanda effect is used. The image forming toner of the present invention is obtained by classifying to a predetermined particle size with a classifier.
Furthermore, inorganic fine particles as external additives and the above-classified toner are sufficiently mixed by a mixer such as a Henschel mixer and passed through a sieve of 250 mesh or more to remove coarse particles and aggregated particles, thereby forming an image. It may be used as a toner.

[Image forming method]
The image forming method of the present invention comprises at least a charging step for charging the surface of an image carrier, an electrostatic latent image forming step for forming an electrostatic latent image on the image carrier, and the electrostatic latent image for image formation. A development process for forming a visible image by developing with toner, a transfer process for transferring the visible image onto a recording medium to form an unfixed image, and fixing the unfixed image on the recording medium The image forming method includes a fixing step, and the image forming toner used for forming the visible image is the image forming toner described above. Here, the toner for image formation can be satisfactorily fixed even if the conveyance speed of the recording medium in the fixing step is 280 mm / second or more.

  According to the image forming method of the present invention, an image forming toner that has excellent low-temperature fixability and heat-resistant storage stability even at high speed and is fixed only at a desired position on a recording medium without causing an offset phenomenon is used. Therefore, even when an image is formed by an electrophotographic image forming apparatus having a high output speed, it is excellent in glossiness, and it is possible to stably output a high-quality image without generating a ghost or the like.

[Image forming apparatus]
The image forming apparatus of the present invention includes at least an image carrier, a charging unit that charges the surface of the image carrier, and an exposure unit that exposes the charged image carrier surface to form an electrostatic latent image. Developing means for developing the electrostatic latent image using an image forming toner to form a visible image; and transfer means for transferring the developed toner image onto a recording medium to form an unfixed image; An image forming apparatus comprising fixing means for fixing the unfixed image to the recording medium,
The image forming toner used to form the visible image is the image forming toner described above.

According to the image forming apparatus of the present invention, an image forming toner that has excellent low-temperature fixability and heat-resistant storage stability even at a high speed and is fixed only at a desired position on a recording medium without causing an offset phenomenon is used. Therefore, even if the process line speed is high, an abnormal image is not generated and the image can be fixed stably. For example, if a tandem full-color image forming apparatus is used, a higher-quality image can be output at a higher speed.
The image forming method and the image forming apparatus of the present invention can be widely applied to electrophotographic application fields using electrophotography (for example, electrostatic copying machines, laser beam printers, etc.).
Hereinafter, a tandem full-color image forming apparatus will be described as an example of the image forming apparatus of the present invention, and will be described with reference to the drawings.

  FIG. 1 is a schematic view for explaining a tandem-type full-color image forming apparatus of the present invention. In FIG. 1, reference numerals (1C, 1M, 1Y, 1K) denote drum-shaped image carriers (hereinafter referred to as “photosensitive members”). This photosensitive member (1C, 1M, 1Y, 1K) rotates in the direction of the arrow in the figure, and at least around that is a charging member (2C, 2M, 2Y, 2K) as a charging means and a developing member as a developing means. (4C, 4M, 4Y, 4K) and cleaning members (5C, 5M, 5Y, 5K) are arranged. The charging members (2C, 2M, 2Y, 2K) are charging members that constitute a charging device for uniformly charging the surface of the photoreceptor.

  From the back side of the photoreceptor between the charging member (2C, 2M, 2Y, 2K) and the developing member (4C, 4M, 4Y, 4K), laser light (3C, 3M, 3Y, 3K) is irradiated, and electrostatic latent images are formed on the photoreceptors (1C, 1M, 1Y, 1K). Then, four image forming elements (6C, 6M, 6Y, 6K) centering on such a photoreceptor (1C, 1M, 1Y, 1K) are along a transfer conveyance belt (10) which is a transfer material conveyance means. Are juxtaposed. The transfer conveying belt (10) as a transfer means includes a developing member (4C, 4M, 4Y, 4K) of each image forming unit (6C, 6M, 6Y, 6K) and a cleaning member (5C, 5M, 5Y, as a cleaning means). 5K), and a transfer brush for applying a transfer bias to the back surface (back surface) of the transfer conveyance belt (10) which is in contact with the back side of the photoconductor side (5C). 11C, 11M, 11Y, 11K). Each image forming element (6C, 6M, 6Y, 6K) is different in the color of the toner inside the developing device, and the others are the same in configuration.

  In the color electrophotographic apparatus having the configuration shown in FIG. 1, the image forming operation is performed as follows. First, in each image forming element (6C, 6M, 6Y, 6K), the charging member (2C, 2M, 2Y) in which the photoconductor (1C, 1M, 1Y, 1K) rotates in the direction of the arrow (direction along with the photoconductor). , 2K), and then an electrostatic latent image corresponding to each color image to be created by laser light (3C, 3M, 3Y, 3K) by an exposure unit (not shown) disposed outside the photoconductor. It is formed.

  Next, the latent image is developed by a developing member (4C, 4M, 4Y, 4K) to form a toner image. The developing members (4C, 4M, 4Y, and 4K) are C (cyan), M (magenta), Y (yellow), and K (black) image forming toners of the present invention (hereinafter referred to as “toners”). )), The color toner images formed on the four photoconductors (1C, 1M, 1Y, 1K) are superimposed on the transfer paper. The transfer paper (7) is fed out from the tray by the paper feed roller (8), temporarily stopped by the pair of registration rollers (9), and then transferred to the transfer conveyance belt (10) in synchronization with the image formation on the photosensitive member. Sent. The transfer paper (7) held on the transfer / conveying belt (10) is conveyed, and the toner images of the respective colors are transferred at the contact positions (transfer portions) with the respective photoreceptors (1C, 1M, 1Y, 1K). It is.

  The toner image on the photosensitive member is transferred onto the transfer paper (by the electric field formed by the potential difference between the transfer bias applied to the transfer brush (11C, 11M, 11Y, 11K) and the photosensitive member (1C, 1M, 1Y, 1K). 7) Transferred on top. Then, the recording paper (7) on which the toner images of four colors are superimposed through the four transfer portions is conveyed to the fixing device (12), where the toner is fixed, and is discharged to a paper discharge portion (not shown). Further, the residual toner remaining on the respective photoconductors (1C, 1M, 1Y, 1K) without being transferred by the transfer unit is collected by the cleaning device (5C, 5M, 5Y, 5K).

In the example of FIG. 1, the image forming elements are arranged in the order of C (cyan), M (magenta), Y (yellow), and K (black) from the upstream side to the downstream side in the transfer paper conveyance direction. However, it is not limited to this order, and the color order is arbitrarily set. Further, when a black-only document is created, it is particularly effective to use the present invention to provide a mechanism for stopping the image forming elements (6C, 6M, 6Y) other than black. Further, although the charging member is in contact with the photosensitive member in FIG. 1, by providing an appropriate gap (for example, about 10 to 200 μm) between them, the wear amount of both can be reduced and the charging member can be attached to the charging member. Less toner filming and good use.
The above-described tandem image forming apparatus can transfer a plurality of toner images at a time, so that high-speed full-color printing is realized.

Further, the image forming means as described above may be fixedly incorporated in the copying apparatus, facsimile, or printer, but may be incorporated in these apparatuses in the form of a process cartridge.
The process cartridge is an apparatus (part) that contains an image carrier (photoconductor) and further includes a means selected from a charging unit, an exposure unit, a developing unit, a transfer unit, and a cleaning unit. If necessary, other means such as a static elimination means may be included. There are many shapes and the like of the process cartridge, but a general example is the one shown in FIG.
Here, the process cartridge includes a photosensitive member (101), and includes a charging unit (102), an exposure unit (103), a developing unit (104), and a cleaning unit (107). It has the means of. In the figure, reference numeral 105 denotes a recording medium (transfer body), and 106 denotes transfer means.

  That is, the process cartridge of the present invention includes an image carrier, a charging unit that charges the surface of the image carrier, an exposure unit that exposes the charged image carrier surface to form an electrostatic latent image, and a formed static charge. It is selected from developing means for developing the electrostatic latent image using image forming toner, transfer means for transferring the developed toner image to the recording medium, and cleaning means for removing the toner remaining on the surface of the image carrier after the transfer. A process cartridge which can be attached to and detached from an image forming apparatus main body integrated with at least one means, and the image forming toner used is the image forming toner of the present invention. It is. It should be noted that other means (for example, static elimination means) may be included as necessary as at least one means to be selected.

  In the process cartridge of the present invention, since the image forming toner of the present invention is supplied from the developing unit, the fixing unit is stably fixed only at a desired position on the recording medium without causing an offset phenomenon due to an unfixed image. High quality images can be output. In addition, it is easy to store and transport and has excellent handling properties.

  EXAMPLES Hereinafter, although an Example and a comparative example are given and this invention is demonstrated further more concretely, this invention is not restrict | limited by these Examples. In the following description, “parts” means parts by weight unless otherwise specified.

[Example 1]
Polyester resin 1 used for the following toner formulation was synthesized as follows.
(Synthesis of polyester resin 1)
443 parts of PO adduct of bisphenol A (propylene oxide added to bisphenol A: hydroxyl value 320) in a reaction vessel equipped with a thermometer, stirrer, cooler and nitrogen introduction tube, 135 parts of diethylene glycol, 422 parts of terephthalic acid Then, 2.5 parts of dibutyltin oxide was added and reacted at 230 ° C. until the acid value became 7, to obtain polyester resin 1. Polyester resin 1 had a Tg of 65 ° C. and a peak molecular weight of 16000. The Tg of polyester resin 1 was measured using a TG-DSC system (TAS-100) manufactured by Rigaku Corporation.

A master batch 1 (prepared by uniformly dispersing a colorant in a part of the polyester resin 1) used for toner formulation was prepared as follows.
The materials shown in the following masterbatch 1 recipe were mixed for 3 minutes at 1500 rpm using a Henschel mixer (Henschel 20B; manufactured by Mitsui Mining Co., Ltd.), and the resulting mixture was mixed at 120 ° C. for 45 minutes using two rolls. After kneading, rolling and cooling and pulverization with a pulverizer gave a master batch 1.

[Prescription of Masterbatch 1]
Water: 25 parts Carbon black (Mitsubishi Chemical # C-44): 50 parts Polyester resin 1: 50 parts

(Manufacture of image forming toner 1)
Using the polyester resin 1, master batch 1 and ketone wax obtained above, an image-forming toner 1 was produced according to the following formulation.

[Formulation of toner 1 for image formation]
Polyester resin 1: 95 parts Ketone wax: 5 parts Masterbatch 1: 10 parts

The materials shown in the prescription of the image forming toner 1 were mixed at 1500 rpm for 3 minutes using a Henschel mixer (Henschel 20B: manufactured by Mitsui Mining Co., Ltd.), and a uniaxial kneader (small bus co-kneader: manufactured by Buss). Were mixed under the following conditions to obtain [Base toner 1].
Set temperature: Inlet part 90 ° C., outlet part 60 ° C., Feed amount: 10 kg / Hr
Since the polyester resin 1 in the master batch 1 used in the prescription of the image forming toner 1 is 50 wt%, the ratio of the polyester resin 1 and the ketone wax in the prescription is 100 parts by weight in total of the polyester resin 1. The ketone wax is 5 parts by weight.

Further, the above [base toner 1] is kneaded and then cooled by rolling, pulverized by a pulverizer, and further, air pressure by using a flat impact plate in an I-type mill (manufactured by Nippon Pneumatic Co., Ltd .: IDS-2 type). Fine pulverization was performed under the conditions of 6.0 atm / cm ² and feed amount: 0.5 kg / hr, followed by classification (132MP manufactured by Alpine Co.) to obtain [Mother toner particles 1].
Thereafter, 100 parts by weight of [toner base particle 1], 1.0 part by weight of hydrophobic silica (external additive A) having a primary particle size of 10 nm as an external additive, a primary particle size of 110 nm produced by a sol-gel method, and substantially spherical. 1.0 part by weight of hexamethyldisilazane hydrophobized silica (external additive B) and 1.0 part of hydrophobic titanium oxide (external additive C) having a primary particle size of 15 nm were added to a Henschel mixer (Henschel manufactured by Mitsui Mining Co., Ltd.). 20B) to obtain [Toner 1].

The above mixing conditions were mixed by repeating the set of rotating for 30 seconds and stopping rotation for 60 seconds 5 times at a peripheral speed of 30 m / sec. The toner obtained here is referred to as [Toner 1]. [Toner 1] had a weight average particle diameter (Dw) of 6.8 μm and a number average particle diameter (Dn) of 6.0 μm. The weight average particle diameter (Dw) and the number average particle diameter (Dn) were measured using the aforementioned Coulter Multisizer II.
Further, the penetration amount of [Toner 1] was 28.1 mm.
The amount of paper immersion of the release agent of toner 1 was measured according to the above-mentioned [Method of evaluating the amount of penetration of release agent], and specifically, was measured under the following conditions.

3 g of [Toner 1] containing a release agent is put into a 50 ml screw vial tube (manufactured by ASONE) as shown in FIG. 3, and the temperature is raised with a heater at 140 ° C. for 1 hour. (A4 horizontal) is soaked in a 1cm x 10cm strip in a horizontal direction for 2 hours, and the length L (mm) infiltrated with the release agent that is visually observed is measured with a caliper. Amount.
However, L (mm) = L0 (mm) −Lt (mm).
As shown in FIG. 3, L0 = the height at which the release agent soaks from the bottom of the strip-shaped paper (distance: mm), Lt = the height at which the toner penetrates from the bottom of the strip-shaped paper (distance: mm) And
Table 1 below summarizes the compounding amount (release agent amount: parts by weight) of the release agent contained in [Toner 1] with respect to polyester resin 1 (100 parts by weight) and the penetration amount L (mm) of the release agent. Show.

Using [Toner 1] obtained above, the fixability (cold offset and hot offset evaluation) was evaluated according to the following evaluation method.
[Evaluation of fixability]
<Cold offset>
Evaluation of low-temperature fixability was performed by visual confirmation of cold offset as follows.
Using the Ricoh copier imageo Neo C600, [Toner 1] was mixed with the carrier used in the copier, and the following image evaluation test was performed.
A toner sample having an adhesion amount of 0.85 mg / cm ² is prepared on an A4 size paper (T6000 70W T-th, manufactured by Ricoh Co., Ltd.) with an image of a 3 cm × 5 cm rectangle at a position 5 cm from the front end of the paper surface. The fixing member was constantly controlled at 140 ° C. and fixed at a linear speed of 300 mm / sec (toner weight was calculated from the weight of the paper before and after image output). At this time, the presence or absence of offset generation was evaluated by visual inspection of the tester. At this time, the toner was determined to be acceptable only when no offset was observed at 140 ° C. The results are shown in Table 1 below.
In Table 1 below, the presence or absence of the occurrence of cold offset is indicated as follows.
・ No cold offset: ○
・ With cold offset: ×
<Hot offset>
Except that the temperature of the fixing member was always controlled at 180 ° C., the hot offset evaluation was performed under the same conditions as in the cold offset evaluation. The results are shown in Table 1 below.
In Table 1 below, presence or absence of occurrence of hot offset is indicated as follows.
・ No hot offset: ○
・ With hot offset: ×

  As shown in Table 1 below, in [Toner 1] of Example 1 of the present invention, neither cold offset nor hot offset occurred, and good results were obtained.

[Example 2]
[Toner 2] was obtained in the same manner as in Example 1 except that the addition amount of ketone wax used in the formulation of image-forming toner 1 of Example 1 was changed from 5 parts to 3 parts.
As a result of measurement in the same manner as in Example 1, [Toner 2] had a weight average particle diameter (Dw) of 6.7 μm and a number average particle diameter (Dn) of 6.1 μm. The penetration amount of [Toner 2] was 27.5 mm.
Table 1 below summarizes the blending amount (release agent amount: parts by weight) of the release agent contained in [Toner 2] with respect to polyester resin 1 (100 parts by weight) and the release agent penetration amount L (mm). Show.

Using [Toner 2] obtained above, evaluation of fixability (evaluation of cold offset and hot offset) was performed in the same manner as in Example 1. The results are shown in Table 1 below.
As shown in Table 1 below, in [Toner 2] of Example 2 of the present invention, neither cold offset nor hot offset occurred, and good results were obtained.

[Example 3]
[Toner 3] was obtained in the same manner as in Example 1 except that the addition amount of ketone wax used in the formulation of image-forming toner 1 of Example 1 was changed from 5 parts to 8 parts.
As a result of measurement in the same manner as in Example 1, [Toner 3] had a weight average particle diameter (Dw) of 6.8 μm and a number average particle diameter (Dn) of 6.1 μm. Further, the penetration amount of [Toner 3] was 28.7 mm.
Table 1 below summarizes the compounding amount (release agent amount: parts by weight) of the release agent contained in [Toner 3] with respect to polyester resin 1 (100 parts by weight) and the release agent penetration amount L (mm). Show.

Using [Toner 3] obtained above, evaluation of fixability (evaluation of cold offset and hot offset) was performed in the same manner as in Example 1. The results are shown in Table 1 below.
As shown in Table 1 below, in [Toner 3] of Example 3 of the present invention, neither cold offset nor hot offset occurred, and good results were obtained.

[Example 4]
[Toner 4] All in the same manner as in Example 1 except that diglyceryl tetrastearate (5 parts) was used instead of the ketone wax (5 parts) used in the formulation of image-forming toner 1 of Example 1. Got.
As a result of measurement in the same manner as in Example 1, [Toner 4] had a weight average particle diameter (Dw) of 6.8 μm and a number average particle diameter (Dn) of 6.3 μm. The penetration amount of [Toner 4] was 15.6 mm.
Table 1 below summarizes the blending amount (release agent amount: parts by weight) of the release agent contained in [Toner 4] with respect to polyester resin 1 (100 parts by weight) and the release agent penetration amount L (mm). Show.

Using [Toner 4] obtained above, evaluation of fixability (evaluation of cold offset and hot offset) was performed in the same manner as in Example 1. The results are shown in Table 1 below.
As shown in Table 1 below, in [Toner 4] of Example 4 of the present invention, neither cold offset nor hot offset occurred, and good results were obtained.

[Example 5]
[Toner 5] in the same manner as in Example 2 except that diglyceryl tetrastearate (3 parts) was used instead of the ketone wax (3 parts) used in the formulation of image-forming toner 2 of Example 2. Got.
As a result of measurement in the same manner as in Example 1, [Toner 5] had a weight average particle diameter (Dw) of 7.0 μm and a number average particle diameter (Dn) of 6.3 μm. The penetration amount of [Toner 5] was 15.5 mm.
Table 1 below summarizes the compounding amount (release agent amount: parts by weight) of the release agent contained in [Toner 5] with respect to polyester resin 1 (100 parts by weight) and the penetration amount L (mm) of the release agent. Show.

Using [Toner 5] obtained above, evaluation of fixability (evaluation of cold offset and hot offset) was performed in the same manner as in Example 1. The results are shown in Table 1 below.
As shown in Table 1 below, in [Toner 5] of Example 5 of the present invention, neither cold offset nor hot offset occurred, and good results were obtained.

[Example 6]
[Toner 6] All in the same manner as in Example 3 except that diglyceryl tetrastearate (8 parts) was used instead of the ketone wax (8 parts) used in the formulation of image-forming toner 3 of Example 3. Got.
As a result of measurement in the same manner as in Example 1, [Toner 6] had a weight average particle diameter (Dw) of 7.1 μm and a number average particle diameter (Dn) of 6.4 μm. Further, the penetration amount of [Toner 6] was 16.3 mm.
Table 1 below summarizes the compounding amount (release agent amount: parts by weight) of the release agent contained in [Toner 6] with respect to polyester resin 1 (100 parts by weight) and the penetration amount L (mm) of the release agent. Show.

Using [Toner 6] obtained above, evaluation of fixability (evaluation of cold offset and hot offset) was performed in the same manner as in Example 1. The results are shown in Table 1 below.
As shown in Table 1 below, in [Toner 6] of Example 6 of the present invention, neither cold offset nor hot offset occurred, and good results were obtained.

[Comparative Example 1]
[Toner 7] was obtained in the same manner as in Example 1 except that carnauba wax (5 parts) was used instead of the ketone wax (5 parts) used in the formulation of image-forming toner 1 of Example 1. It was.
As a result of measurement in the same manner as in Example 1, [Toner 7] had a weight average particle diameter (Dw) of 6.8 μm and a number average particle diameter (Dn) of 6.0 μm. Further, the penetration amount of [Toner 7] was 12.0 mm.
Table 2 below summarizes the blending amount (release agent amount: parts by weight) of the release agent contained in [Toner 7] with respect to polyester resin 1 (100 parts by weight) and the release agent penetration amount L (mm). Show.

Using the [Toner 7] obtained above, evaluation of fixability (evaluation of cold offset and hot offset) was performed in the same manner as in Example 1. The results are shown in Table 2 below.
As shown in Table 2 below, cold offset was confirmed in [Toner 7] of Comparative Example 1, and problematic results were obtained.

[Comparative Example 2]
[Toner 8] was obtained in the same manner as in Example 2 except that carnauba wax (3 parts) was used in place of the ketone wax (3 parts) used in the formulation of image-forming toner 2 of Example 2. It was.
As a result of measurement in the same manner as in Example 1, [Toner 8] had a weight average particle diameter (Dw) of 6.8 μm and a number average particle diameter (Dn) of 6.1 μm. Further, the penetration amount of [Toner 8] was 11.7 mm.
Table 2 below summarizes the blending amount (release agent amount: parts by weight) of the release agent contained in [Toner 8] with respect to polyester resin 1 (100 parts by weight) and the release agent penetration amount L (mm). Show.

Using [Toner 8] obtained above, evaluation of fixability (evaluation of cold offset and hot offset) was performed in the same manner as in Example 1. The results are shown in Table 2 below.
As shown in Table 2 below, in [Toner 8] of Comparative Example 2, both cold offset and hot offset occurred, and problematic results were obtained.

[Comparative Example 3]
[Toner 9] was obtained in the same manner as in Example 3, except that carnauba wax (8 parts) was used instead of the ketone wax (8 parts) used in the formulation of image-forming toner 3 of Example 3. It was.
As a result of measurement in the same manner as in Example 1, [Toner 9] had a weight average particle diameter (Dw) of 6.7 μm and a number average particle diameter (Dn) of 6.1 μm. The penetration amount of [Toner 9] was 11.9 mm.
Table 2 below summarizes the compounding amount (release agent amount: parts by weight) of the release agent contained in [Toner 9] with respect to polyester resin 1 (100 parts by weight) and the release agent penetration amount L (mm). Show.

Using [Toner 9] obtained above, evaluation of fixability (evaluation of cold offset and hot offset) was performed in the same manner as in Example 1. The results are shown in Table 2 below.
As shown in Table 2 below, cold offset was confirmed in [Toner 9], and problematic results were obtained.

[Comparative Example 4]
[Toner 10] was obtained in the same manner as in Example 1 except that paraffin wax (5 parts) was used in place of the ketone wax (5 parts) used in the formulation of image-forming toner 1 of Example 1. .
As a result of measurement in the same manner as in Example 1, [Toner 7] had a weight average particle diameter (Dw) of 6.8 μm and a number average particle diameter (Dn) of 6.0 μm. The penetration amount of [Toner 10] was 41.6 mm.
Table 2 below summarizes the compounding amount (release agent amount: parts by weight) of the release agent contained in [Toner 10] with respect to polyester resin 1 (100 parts by weight) and the penetration amount L (mm) of the release agent. Show.

Using [Toner 10] obtained above, evaluation of fixability (evaluation of cold offset and hot offset) was performed in the same manner as in Example 1. The results are shown in Table 2 below.
As shown in Table 2 below, cold offset was confirmed in [Toner 10] of Comparative Example 4, and problematic results were obtained.

[Comparative Example 5]
[Toner 11] was obtained in the same manner as in Example 2 except that paraffin wax (3 parts) was used in place of the ketone wax (3 parts) used in the formulation of image-forming toner 2 of Example 2. .
As a result of measurement in the same manner as in Example 1, [Toner 11] had a weight average particle diameter (Dw) of 6.8 μm and a number average particle diameter (Dn) of 6.1 μm. The penetration amount of [Toner 8] was 44.4 mm.
Table 2 below summarizes the compounding amount (release agent amount: parts by weight) of the release agent contained in [Toner 11] with respect to polyester resin 1 (100 parts by weight) and the release agent penetration amount L (mm). Show.

Using the [Toner 11] obtained above, evaluation of fixability (evaluation of cold offset and hot offset) was performed in the same manner as in Example 1. The results are shown in Table 2 below.
As shown in Table 2 below, cold offset was confirmed in [Toner 11] of Comparative Example 5, and problematic results were obtained.

[Comparative Example 6]
[Toner 12] was obtained in the same manner as in Example 3 except that paraffin wax (8 parts) was used instead of ketone wax (8 parts) used in the formulation of image-forming toner 3 of Example 3. .
As a result of measurement in the same manner as in Example 1, [Toner 12] had a weight average particle diameter (Dw) of 6.7 μm and a number average particle diameter (Dn) of 6.1 μm. The penetration amount of [Toner 12] was 43.5 mm.
Table 2 below summarizes the blending amount (release agent amount: parts by weight) of the release agent contained in [Toner 12] with respect to polyester resin 1 (100 parts by weight) and the penetration amount L (mm) of the release agent. Show.

Using [Toner 12] obtained above, evaluation of fixability (evaluation of cold offset and hot offset) was performed in the same manner as in Example 1. The results are shown in Table 2 below.
As shown in Table 2 below, cold offset was confirmed in [Toner 12], and problematic results were obtained.

[Comparative Example 7]
[Toner 13] was obtained in the same manner as in Example 1 except that the addition amount of ketone wax used in the formulation of image-forming toner 1 of Example 1 was changed from 5 parts to 2 parts.
As a result of measurement in the same manner as in Example 1, [Toner 13] had a weight average particle diameter (Dw) of 6.7 μm and a number average particle diameter (Dn) of 6.1 μm. The penetration amount of [Toner 13] was 27.4 mm.
The blending amount (release agent amount: parts by weight) of the release agent contained in [Toner 13] with respect to the polyester resin 1 (100 parts by weight) and the penetration amount L (mm) of the release agent are summarized in Table 2 below. Show.

Using [Toner 13] obtained above, evaluation of fixability (evaluation of cold offset and hot offset) was performed in the same manner as in Example 1. The results are shown in Table 2 below.
As shown in Table 2 below, hot offset was confirmed in [Toner 13], and problematic results were obtained.

[Comparative Example 8]
[Toner 14] was obtained in the same manner as in Example 1 except that the addition amount of the ketone wax used in the formulation of image-forming toner 1 of Example 1 was changed from 5 parts to 10 parts.
As a result of measurement in the same manner as in Example 1, [Toner 14] had a weight average particle diameter (Dw) of 6.6 μm and a number average particle diameter (Dn) of 6.1 μm. Further, the penetration amount of [Toner 14] was 29.0 mm.
Table 2 below summarizes the blending amount (release agent amount: parts by weight) of the release agent contained in [Toner 14] with respect to polyester resin 1 (100 parts by weight) and the release agent penetration amount L (mm). Show.

Using [Toner 14] obtained above, evaluation of fixability (evaluation of cold offset and hot offset) was performed in the same manner as in Example 1. The results are shown in Table 2 below.
As shown in Table 2 below, cold offset was confirmed in [Toner 14], and problematic results were obtained.

[Comparative Example 9]
[Toner 15] All in the same manner as in Example 1 except that diglyceryl monostearate (5 parts) was used instead of the ketone wax (5 parts) used in the formulation of image-forming toner 1 of Example 1. Got.
As a result of measurement in the same manner as in Example 1, [Toner 15] had a weight average particle diameter (Dw) of 6.9 μm and a number average particle diameter (Dn) of 6.1 μm. The penetration amount of [Toner 7] was 1.5 mm.
The blending amount (release agent amount: parts by weight) of the release agent contained in [Toner 15] with respect to the polyester resin 1 (100 parts by weight) and the penetration amount L (mm) of the release agent are summarized in Table 2 below. Show.

Using [Toner 15] obtained above, evaluation of fixability (evaluation of cold offset and hot offset) was performed in the same manner as in Example 1. The results are shown in Table 2 below.
As shown in Table 2 below, in [Toner 15] of Comparative Example 9, both cold offset and hot offset occurred, and problematic results were obtained.

  As can be seen from the above evaluation results, the image forming toner of the present invention can output a stable image without occurrence of ghosting and the like without an offset phenomenon (cold offset and hot offset) even at a high fixing speed. Further, the image forming toner of the present invention has both low-temperature fixability and heat-resistant storage stability, and glossiness is maintained even at high-speed output. Therefore, when used as a one-component developer and a two-component developer, it can be applied to an image forming method, an image forming apparatus, and a process cartridge having a high process linear velocity. In particular, it is useful for application fields using electrophotography (for example, electrostatic copying machines and laser beam printers).

1 is a schematic diagram for explaining an image forming apparatus and an image forming method according to the present invention. It is the schematic for demonstrating the process cartridge of this invention. It is a schematic diagram for demonstrating the penetration amount evaluation method of the mold release agent in this invention.

Explanation of symbols

1C, 1M, 1Y, 1K Photoconductor 2C, 2M, 2Y, 2K Charging member 3C, 3M, 3Y, 3K Laser light 4C, 4M, 4Y, 4K Developing member 5C, 5M, 5Y, 5K Cleaning member 6C, 6M, 6Y , 6K image forming element 7 transfer paper 8 feeding roller 9 registrar 10 transfer conveying belt 11C, 11M, 11Y, 11K transfer brush 12 fixing device 101 photoconductor 102 contact charging device 103 image exposure 104 developing device 105 transfer body 106 contact transfer Device 107 Cleaning unit

Claims (11)

In an image forming toner in which a compound containing at least a colorant, a binder resin, and a release agent is pulverized and classified after undergoing a melting and kneading step.
The release agent is blended in the range of 3 to 8 parts by weight with respect to 100 parts by weight of the binder resin, and the penetration amount of the release agent calculated by the following evaluation method is 15 mm to 30 mm. A toner for image formation.
[Method of evaluating penetration of release agent]
Into a glass container having a diameter of about 35 mm and a capacity of 50 ml, 6 g of the image forming toner is charged, heated to a temperature at which the release agent is sufficiently melted, and heated for 1 hour. One end of a strip-shaped paper (the longitudinal direction of the strip shape is a horizontal direction) obtained by cutting Ricoh Co. copy paper T6000 (A4 horizontal side) into 1 cm × 10 cm is immersed in the melted toner, and after maintaining for 2 hours, visually Observed height L0 (mm) where the release agent soaked from one end (bottom side) of the strip-shaped paper and height Lt (mm) where the toner soaked from one end (bottom side) of the strip-shaped paper, respectively. Measure and calculate the permeation amount L (mm) of the release agent from the following equation. L (mm) = L0 (mm) -Lt (mm)   The image forming toner according to claim 1, wherein the release agent is a ketone wax or diglyceryl tetrastearate.   The image forming toner according to claim 1, wherein the binder resin contains a polyester resin as a main component.   4. The image forming toner according to claim 1, wherein the toner has a weight average particle diameter of 3.5 μm to 10 μm.   A one-component developer comprising the image forming toner according to any one of claims 1 to 3.   A two-component developer comprising the image forming toner according to any one of claims 1 to 3 and a carrier. A charging process for charging at least the surface of the image bearing member, an electrostatic latent image forming process for forming an electrostatic latent image on the image bearing member, and development of the electrostatic latent image using image forming toner. Image formation comprising: a development step for forming a visual image; a transfer step for transferring the visible image onto a recording medium to form an unfixed image; and a fixing step for fixing the unfixed image to the recording medium. A method,
The image forming method according to claim 1, wherein the image forming toner used for forming the visible image is the image forming toner according to claim 1.   The image forming method according to claim 7, wherein a conveyance speed of the recording medium in the fixing step is 280 mm / second or more. At least an image carrier, a charging unit that charges the surface of the image carrier, an exposure unit that exposes the charged image carrier surface to form an electrostatic latent image, and forms the electrostatic latent image. Developing means for developing a visible image by using the toner for transfer, transfer means for transferring the developed toner image onto a recording medium to form an unfixed image, and the unfixed image as the recording medium An image forming apparatus comprising a fixing unit for fixing to the image forming apparatus,
An image forming apparatus according to claim 1, wherein the image forming toner used for forming the visible image is the image forming toner according to claim 1.   The image forming apparatus according to claim 9, wherein a conveyance speed of the recording medium at the time of fixing by the fixing unit is 280 mm / second or more. An image carrier;
A charging unit that charges the surface of the image carrier, an exposure unit that exposes the charged image carrier surface to form an electrostatic latent image, and develops the formed electrostatic latent image using image forming toner. At least one means selected from developing means, transfer means for transferring the developed toner image to a recording medium, and cleaning means for removing toner remaining on the surface of the image carrier after transfer;
Is a process cartridge that can be attached to and detached from the integrated image forming apparatus body,
The process cartridge according to claim 1, wherein the image forming toner used is the image forming toner according to claim 1.

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