JPS61240254A - Toner - Google Patents

Abstract

PURPOSE:To enhance electrification characteristics and fixability and to enable a latent image to be developed and fixed satisfactorily by incorporating a cross- linkable polyester and an epoxy resin having an epoxy equiv. of >=1,500 and a positively chargeable electrostatic charge controller in an amt. of 3-12wt% of the total weight of a toner. CONSTITUTION:The binder contains the cross-linkable polyester prepared by polymerizing polyol and polybasic acid, one of both being a polyfunctional component having >=3 valences and the epoxy resin having an epoxy equiv. of >=1,500 in an amt. of 50-95wt% of the binder. A toner is prepared by adding the positively triboelectrifiable charge controller and a colorant and other necessary additives to said binder. This charge controller acts when the toner is rubbed, so as to positively charge the toner, and it is embodied by nigrosine and azine type dyes each having 2-16C, etc. and it is used in an amt. of 3-12wt% of the total weight of the toner.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a positively chargeable toner for developing an electrostatic latent image or a magnetic latent image.

[Conventional technology]

Currently, as a method for forming a visible image from given image information, a method using electrostatic latent images is widely used, and a method using magnetic latent images is also coming into use. . In developing these latent images,
A powdered toner is used which adheres to the latent image and makes the latent image visible.

Such toners are required to have excellent initial properties such as charging properties and fixing properties so that good results can be obtained in each process that the toner undergoes up to the formation of a visible image.

Incidentally, there are many cases in which printed matter formed by toner development must be stored for a long period of time or semi-permanently. In such cases, the printed matter, which has a visible image formed on paper, is usually stored in a so-called document holder made of a resin film, or one or both sides of the printed matter are covered with a laminated resin film. Often.

However, if storage is carried out using such a resin cover, over time, the toner that forms the image will stick to the resin cover that is in close contact with the surface of the print, and when the print is separated from the cover, the toner will peel off from the print. As a result, accidents often occur in which printed materials are damaged by the burrs.

This is because the resin material used for storage resin covers is usually a vinyl chloride polymer and always contains a plasticizer, and this plasticizer acts on the binder resin that makes up the toner to plasticize it. This is thought to be due to the fact that

[Problems to be solved by the invention]

The present invention solves the above-mentioned problem, namely, when a printed matter comes into contact with a resin film such as a vinyl polymer.
To solve the problem that the toner constituting the visible image of printed matter changes in quality due to the influence of resin components, to have excellent charging characteristics and fixing characteristics, and to perform good development and fixing of latent images. It is an object of the present invention to provide a toner that can form visible images with high resistance to resin and good storage stability.

Means for Solving Problem C] The above problem is that the binder contains a crosslinkable polyester and an epoxy resin having an epoxy equivalent of 1500 or more, and the content ratio of the epoxy resin is 50% to the binder.
The problem is solved by a toner characterized in that a positively chargeable charge control agent is added at a content ratio of 3 to 12% by weight based on the total amount of the toner.

The present invention will be explained in detail below.

In the present invention, a monomer composition consisting of a polyhydric alcohol and a polybasic acid, in which at least one of the polyhydric alcohol and the polybasic acid contains a polyfunctional component having a valence of 3 or more, is obtained by polymerizing the monomer composition. A binder is a mixture of a crosslinkable polyester and an epoxy resin having an epoxy equivalent of 1,500 or more in a specific ratio, and a positive charge control agent, a colorant, and other necessary components are added to the binder to form a toner. Configure.

In the above, examples of dihydric alcohols used in the synthesis of crosslinkable polyester include ethylene glycol, diethylene glycol, triethylene glycol,
．． Diols such as 2-propylene glycol, 1.3-propylene glycol, 1.4-7" tanediol, neopentyl glycol, 1.4-butynediol, 1.
Examples include 4-bis(hydroxymethyl)cyclohexane, and etherified bisphenols such as bisphenol A, hydrogenated bisphenol A1, polyoxyethylene/bisphenol A1, polyoxypropylenated bisphenol A, and others.

Examples of trihydric or higher polyhydric alcohols that participate in crosslinking of polyester include sorbitol and ■.

2.3.6-hexanetetrol, 1.4-sorbitan, hentaerythritol, dipentaerythritol, tripentaerythritol, sucrose, 1,2.4-butanetriol, 1,2.5-pentanetriol, glycerol, 2 -methylpropanetriol, 2-methyl-1
, 2,4-butanetriol, trimethylolethane,
Mention may be made of trimethylolpropane, 1,3.5-trihydroxymethylbenzene, and others.

Examples of polybasic acids used to synthesize crosslinkable polyesters include maleic acid, fumaric acid, mesaconic acid, citraconic acid, itaconic acid, glutaconic acid, phthalic acid, isophthalic acid, terephthalic acid, cyclohexanedicarboxylic acid, and succinic acid. Examples include adipic acid, sepatic acid, malonic acid, anhydrides of these acids, dimers of lower alkyl esters and liluic acid, and other divalent organic acids.

Examples of trivalent or higher polybasic acids involved in crosslinking polyester include 1.2.4-benzenetricarboxylic acid,
1,2.5-benzenetricarboxylic acid, 1゜2.4-cyclohexanetricarboxylic acid, 2.5.1-naphthalenetricarboxylic acid, 1,2.4-naphthalenetricarboxylic acid, 1,2.4-butanetricarboxylic acid, 1.2.5-
Hexanetricarboxylic acid, 1,3-dicarboxyl-2
-Methyl-2-methylenecarboxypropane, tetra(
(methylenecarboxyl)methane, 1.2.7.8-octane tetracarboxylic acid, embol trimer acid and acid anhydrides thereof, and others.

The trihydric or higher polyhydric alcohol and/or polybasic acid component involved in crosslinking the polyester is contained in a proportion of 5 to 80 mol% in each of the alcohol component or acid component as a structural unit in the polymer. is preferable.

The crosslinkable polyester used in the present invention preferably has an aliphatic hydrocarbon group having 3 to 22 carbon atoms in its side chain. By using such a branched non-linear crosslinkable polyester, the non-offset properties of the toner are improved. In order to introduce the aliphatic hydrocarbon group into the crosslinkable polyester, a polybasic acid or a polyhydric alcohol having a divalent or higher valence having the aliphatic hydrocarbon group in its side chain is used as a monomer. As such monomers, for example, n-dodecenylsuccinic acid, isododecenylsuccinic acid, n-dodecylsuccinic acid, iso-octylsuccinic acid, n-octylsuccinic acid, n-octylsuccinic acid, etc. can be suitably used. The amount of the above-mentioned divalent or higher polybasic acid and polyhydric alcohol having an aliphatic hydrocarbon group in the side chain is 1 to 1 to 100% of the total monomer component.
It is 50 mol%, preferably 10 to 30 mol%. If the amount used exceeds 50 mol %, the non-cohesive properties of the toner will be insufficient, and if the amount used is less than 1 mol %, the low temperature fixing properties of the toner will become insufficient.

The epoxy resin used in the present invention has an epoxy equivalent of 1,500 or more, preferably 1,500 to 3,000. Here, the epoxy equivalent refers to the number of equivalents per epoxy group (g/eq), and specifically, it is the value obtained by dividing the average molecular weight by the epoxy group per molecule. The measurement of epoxy equivalent is mainly carried out by direct titration of α-epoxy groups.

Furthermore, the epoxy resin used in the present invention has a melting point in the range of 60 to 160°C, preferably 115 to 140°C, and a glass transition point of 55
℃ or higher is preferably used. Particularly preferred epoxy resins include bisphenol A epoxy resins.

A specific example of an epoxy resin that can be suitably used in the present invention is 1007.
1009 (manufactured by Yuka Shell Epoxy Co., Ltd.), product name r
70 sold as Araldite GY J
97.6097.6099 (manufactured by Ciba Geigy)
, 667 sold under the trade names rD, E, R, J
．． 668 (manufactured by Dow Chemical International), and others.

The content ratio of the above epoxy resin is 5% to the binder.
It is 0 to 95% by weight, preferably 60 to 90% by weight.

If the content of the epoxy resin in the binder exceeds 95% by weight, the off-cent phenomenon tends to occur, and bis[4-(2,3-epoxy) contained in the epoxy resin is irritating to human skin. propoxy) propane CCa5N0.167-54-3) (rD
C, BAJ) concentration becomes high, which is not preferable.

In addition, the content ratio of the epoxy resin to the binder is 5
If it is less than 0% by weight, the proportion of negatively chargeable crosslinked polyester becomes relatively large, so the toner tends to be negatively charged, and therefore has good positive chargeability and a high rate of increase in charge amount due to friction. Not only is it difficult to obtain a positively chargeable toner, but also the softening point of the toner becomes high, resulting in insufficient low-temperature fixability.

The toner of the present invention is configured by using a mixture of the above-mentioned crosslinkable polyester and epoxy resin as a binder, and containing a positively chargeable charge control agent, a colorant, and a property improver added as necessary, In the case of a magnetic toner, a magnetic substance is contained together with or instead of a colorant.

The positively chargeable charge control agent used in the present invention is:
It acts so that when the toner is rubbed, the toner becomes positively charged. Specific examples of such positively chargeable charge control agents include nigrosine, azine dyes containing an alkyl group having 2 to 16 carbon atoms, basic dyes (e.g. C, 1B
asic Yellow 2 (C, 1, No, 4100
0), C, 1, Ba5ic Yellow 3, C,
I.

Ba5ic Red 1 (C, 1, No, 45160
), C,1,Ba5ic Violetl(C,1,N
o, 42535), C, 1, Ba5ic Blue
1 (C, 1, No.

42025), C,1,Ba5ic Green 1(
C, 1, No. 42040), and other lake pigments of these basic dyes (lake-forming agents include phosphotungstic acid, phosphomolybdic acid, phosphotungsten molybdic acid, tannic acid, lauric acid, gallic acid, ferricyanide). *), C0I, 5olv
ent Black 3 (C, 1, No, 26150)
, Hansa Yellow G (C, 1, No.

11680), C, 1, Pigment Black
1, and others.

Specific examples of positively chargeable charge control agents that can be suitably used in the present invention include N-1, N-2, N-4, N-5, and N-1 sold under the trade name "Bontron".
-7, N-11, and others.

The proportion of the positively chargeable charge control agent used is 3 to 12% by weight based on the total amount of the toner. If this proportion is too small, the effect of adding the charge control agent will be insufficient, and the charge build-up will be very poor. Furthermore, if the usage ratio is excessive, the electrical resistance of the toner becomes insufficient and the amount of charge becomes low, making it impossible to obtain an appropriate charging state.

As the coloring agent, carbon blank, nigrosine dye (C, 1, No. 50415B), aniline blue (
C, 1, No. 50405), Calco Oil Blue (C
,1,No.

azoecBlue 3), chrome yellow (C, I
, No. 14090), Ultramarine Blue (C,
1, No. 77103), DuPont Oil Red (C
, 1, No. 26105), Quinoline Yellow (C,
1, No, 47005), Methylene Blue Chloride (C, 1, No, 52015), Phthalocyanine Blue (C, 1, No, 74160), Malachite Green Off Sarate (C, 1, No, 42000), Lamp Black (C, 1, No.

77266), Rose Bengal (C, 1, No. 454)
35), perylene scarlet (C, 1, No, 71
137), mixtures thereof, and others. These colorants need to be contained in a sufficient proportion to form a visible image with sufficient concentration, and are usually 1 to 20 parts by weight per 100 parts by weight of the binder. .

The magnetic material may be a metal or alloy that exhibits ferromagnetism such as ferrite, magnetite, iron, cobalt, or nickel, or a compound containing these elements, or a material that does not contain a ferromagnetic element but can be prepared by subjecting it to appropriate heat treatment. Mention may be made of alloys which become ferromagnetic, for example alloys of the type called Heusler alloys containing manganese and copper, such as manganese-copper-aluminum, manganese-copper-tin, or chromium dioxide, among others. These magnetic substances are uniformly dispersed in the binder in the form of fine powder with an average particle size of 0.1 to 1 micron. And its content is
The amount is 20 to 70 parts by weight, preferably 40 to 70 parts by weight per 100 parts by weight of toner.

Examples of the property improving agent include an anti-offset agent, a lubricant for improving fluidity, and others.

The toner of the present invention is two-component developed by being mixed with a carrier made of iron powder, ferrite powder, glass beads, etc., or a carrier whose surface is coated with a specific resin to improve its durability, charge controllability, etc. It can be used as a developer or as a one-component developer when it contains a magnetic substance, for developing electrostatic latent images or magnetic latent images.

〔Example〕

Examples of the present invention will be described below, but the present invention is not limited thereto.

Synthesis Example 1 (Crosslinkable Polyester A) Polyoxypropylene (2,2”)-bis(4-hydroxyphenyl)propane 211g Terephthal M 299g Pentaerythritol 82g or more of the substance was mixed with a temperature needle, a stainless steel stirrer, and a glass Place it in a round-bottomed flask equipped with a gas inlet tube and a flow-down condenser, set this flask on a mantle heater, and introduce nitrogen gas through the gas inlet tube to raise the temperature while maintaining an inert atmosphere inside the flask. Then, 0.05 g of dibutyltin oxide was added, and the reaction was carried out at a temperature of 200° C. while monitoring the reaction at the softening point.

The softening point of the crosslinkable polyester A thus obtained by the ring and ball method (according to the method of JIS K2531-1960; the same applies hereinafter) was 135°C, and the chloroform insoluble content was 17% by weight.

Synthesis Example 2 (Crosslinkable Polyester B) Polyoxypropylene (2,2)-2,2-bis(4-
Hydroxyphenyl)propane 700 g Fumaric acid 150 g Dodecenylsuccinic anhydride 55.4 g Hydroquinone At least 0.1 g of the substance in a round bottom flask equipped with a thermometer, stainless steel stirrer, glass gas inlet tube and down-flow condenser. The flask was placed in a mantle heater, and nitrogen gas was introduced through the gas inlet tube to raise the temperature while maintaining an inert atmosphere inside the flask, and the reaction was carried out at a temperature of 250°C with stirring. When the water produced by the reaction stopped flowing out, the acid value was measured and found to be 1.5.

Furthermore, 65.4 g of 1,2.4-benzenetricarboxylic acid anhydride was added and reacted for about 8 hours, and the reaction was terminated when the acid value reached 20.

The softening point of the crosslinkable polyester B thus obtained was 128°C by the ring and ball method.

Synthesis Example 3 (Crosslinkable Polyester C) Polyoxypropylene (2,2)-2,2-bis(4-
Hydroxyphenyl)propane 650 g Fumaric acid 120 g Isododecenylsuccinic anhydride 55.4 g of the above substances are placed in a round bottom flask equipped with a thermometer, a stainless steel stirrer, a glass gas inlet tube and a down-flow condenser. Set the flask on a mantle heater, introduce nitrogen gas from the gas inlet tube to raise the temperature while keeping the inside of the flask in an inert atmosphere, and bring it to a temperature of 22°C while stirring.
The reaction was carried out at 0°C. When the water produced by the reaction stopped flowing out, the acid value was measured and found to be 1.5.

Further, 79 g of 1.2.4-benzenetricarboxylic acid anhydride was added and reacted at a temperature of 200°C, and the reaction was terminated when the softening point according to the ring and ball method reached 130°C.

Example 1 Crosslinkable polyester A 20 parts by weight Epoxy resin "Epicote 1007 J (epoxy equivalent: 205
1) 80 parts by weight charge control agent “Bontron N-2J (manufactured by Orient Chemical Co., Ltd.)
7 parts by weight polypropylene [Viscol 660
PJ (manufactured by Mitsubishi Kasei Corporation)
A mixture containing 3 parts by weight of carbon black 1130J (manufactured by Mitsubishi Kasei Corporation) and 6 parts by weight or more was prepared in a Henschel mixer for 15 minutes, and then melt-kneaded with a two-wheeled extruder. After being cooled to room temperature and solidified, it was coarsely crushed using a hammer mill, and then finely crushed using a type 1 mill. The obtained fine powder was classified using an air classifier, and the average particle size was 10.4 to 11.
A toner of 8 μm was obtained.

Examples 2 to 5 and Comparative Examples 1 to 4 Various toners were obtained in the same manner as in Example 1 according to the following formulations.

Example 2 Crosslinkable polyester 8 40 parts by weight Epoxy resin "Epikote 1007 J" 60 parts by weight Charge control agent "Bontron N-11" (manufactured by Orient Chemical Co., Ltd.)
9 parts by weight Polypropylene "Viscol 660PJ 3 parts by weight Carbon black RL 3
0J 6 parts by weight Example 3 Cross-linkable polyester C40 parts by weight Epoxy resin "Epicoat 1007460 parts by weight Charge control agent" Bontron N-4J (manufactured by Orient Chemical Co., Ltd.)
12 parts by weight polypropylene
Viscole 660PJ 3 parts by weight Carbon black RL 30J 6 parts by weight Example 4 Cross-linkable polyester 8 30 parts by weight Epoxy resin "Epicoat 1007 J 70 parts by weight Charge control agent" Bontron N-IJ (manufactured by Orient Chemical Co., Ltd.)
4 parts by weight Polypropylene "Viscol 660PJ 3 parts by weight Carbon black RL
3QJ 6 parts by weight Example 5 Crosslinkable polyester 8 40 parts by weight Epoxy resin "Ebiko" 1007 J 60 parts by weight Charge control agent "Bontron N-11J 9 parts by weight Carbon black RL 30J 6 parts by weight Comparative example 1 Crosslinkable polyester A 4 Parts by weight Epoxy resin "Epikoat 1007 J 96 parts by weight Charge control agent [Bontron N-11J 5 parts by weight Polypropylene [Viscol 660PJ 3 parts by weight Carbon black RLL 30J 6 parts by weight Comparative example 2 Crosslinkable polyester 8 55 parts by weight Epoxy resin "Epikoat" 1007445 parts by weight Charge control agent "Bontron N-IJ 15 parts by weight Polypropylene" Viscole 660PJ 3 parts by weight Carbon black rll
30J 6 parts by weight Comparative Example 3 Crosslinkable polyester A 10 parts by weight Epoxy resin "Epikote 1007 J 90 parts by weight Charge control agent [Bontron N-2J 2 parts by weight 1 part by weight Polypropylene [Viscol 660PJ 3 parts by weight Carbon blank rll 30J 6 parts by weight Comparison Example 4 Styrene-acrylic resin (styrene/methyl methacrylate/butyl acrylate-75/10/15)
100 parts by weight Charge control agent "Bontron N-4J 4 parts by weight Polypropylene" Viscoel 66QPJ 3 parts by weight Carbon black l130
J For each toner of 6 parts by weight or more,
The following items were tested.

(1) Charging characteristics Each of the above toners and 100 to 200 meshes of conductive spherical carrier were mixed to prepare a developer having a toner concentration of 2.0% by weight. Each of these developers is shaken by a shaking machine.
After mixing for 1 minute using es+-YSJ (manufactured by Yayoi Co., Ltd.), the charge amount Q/M (unit: microcoulombs/g) of the toner per unit weight was measured by a blow-off method. Further, the mixing time was set to 10 minutes, and the amount of charge Q/M (unit: 2 microcoulombs/g) per unit weight of the toner was measured in the same manner, and the increase in charge due to friction (hereinafter referred to as "rise of charge") was measured. ) was considered to be prompt.

(2) Softening point The softening point of each toner was measured using a Koka type flow tester r CTF.
-500J (manufactured by Shimabara Seisakusho).

(3) Fixing properties A developer with a toner concentration of 2.5% by weight was prepared by mixing each of the toners with 100 to 200 meshes of carrier made of iron powder coated with styrene-acrylic resin. , each of which provides electrophotographic reproduction 49 rU
- Using Bix 4500J (manufactured by Konishi Roku Photo Industry Co., Ltd.), we conducted a real-print test using the steps of developing an electrostatic latent image, transferring the toner image to transfer paper, and fixing the toner image with a heat roller fixing device. For each, the minimum fixing temperature and offset occurrence temperature were determined.

(i) Minimum fixing temperature Regarding the minimum fixing temperature, a heat roller whose surface layer is made of Teflon (polytetrafluoroethylene manufactured by DuPont) and a heat roller whose surface layer is made of silicone rubber rKE-1300RTVJ
The operation of fixing the toner image of the sample toner transferred onto a 64 g/- transfer paper at a high linear speed of 350 ml/sec using a fixing device consisting of a pressure roller (manufactured by Shin-Etsu Chemical Co., Ltd.) was performed using heat. Set roller temperature to 100℃
The temperature is then raised stepwise by 10°C and repeated at each temperature, and Kimwipe rubbing is applied to the formed fixed image. did. Note that the fixing device used here does not have the X7 U controller oil supply mechanism.

(ii) Offset generation temperature To measure the offset generation temperature, transfer the toner image and perform the fixing process using the above-mentioned fixing device, and then transfer a blank transfer paper to the fixing device under the same conditions. The operation of sending the toner to the printer and observing whether or not toner stains occur is repeated while increasing the set temperature of the heat roller of the fixing unit sequentially, and the off-cent occurs at the lowest set temperature at which toner stains occur. Temperature.

(4) Resin durability vs. resin durability was determined by placing a commercially available polyvinyl chloride cover film in close contact with the surface of a printed matter formed in a continuous copy test, applying a load of 100 g/am'', and applying a load of 100 g/am'' at a temperature of 70°C. The cover film was left for 3 hours in an atmosphere of , “Q” if no metastasis was observed, “Δ” if slight metastasis was observed, and “×” if significant metastasis was observed.
" is displayed.

(5) DGBAt 1 degree The concentration of DGBA contained in the epoxy resin in each toner was measured by liquid chromatography. The sample used at this time was 5 g of toner sample 200+*
Extracted in 0ml methanol for 5 hours.

Since DGBA is irritating to human skin, it is desired that its content be as low as possible, and as a standard, it is preferably 1% or less.

The above results are shown in Table 1.

As is clear from the results in Table 1, in the examples of the present invention, good results were obtained across all evaluation items, but in the comparative examples, insufficient results were obtained in any of the evaluation items. It was done.

In other words, in Comparative Example 1, the content ratio of the epoxy resin is too high, so the DGBAtJ1 degree is large, and not only is it inferior in terms of safety to the human body, but also the occurrence of an offset phenomenon is significant.In Comparative Example 2, the crosslinking property is Due to the excessive content of polyester, the positive chargeability of the toner is insufficient, and as a result, the build-up of charge due to friction is slow, and it takes a long time to reach the desired amount of charge, making it impossible to perform a quick charging process. In Comparative Example 3, since the content of the positively chargeable charge control agent was too small, the build-up of charge due to friction was slow, and therefore it took a long time to reach a predetermined charge amount, and
Charging processing can be performed71. In Comparative Example 4, since styrene-acrylic resin is used, the durability against the resin is insufficient.

〔Effect of the invention〕

As described above, the toner of the present invention uses a blend of a specific crosslinkable polyester and an epoxy resin in a specific ratio as a binder, and further contains a positively chargeable charge control agent in a specific ratio. It has excellent properties as a developer, especially excellent developability and fixing properties, and can form good visible images. Even when a cover such as a film is provided, there is no adverse effect due to this, and therefore a visible image that can be stored semi-permanently is formed.

Hereinafter, the effects of the present invention will be specifically explained.

(1) Excellent charging characteristics.

Generally, polyester resins have strong negative chargeability, but in the present invention, by mixing an epoxy resin with crosslinkable polyester, the negative chargeability of the polyester resin itself is weakened, and the toner becomes negatively charged. It becomes less sexual. Furthermore, in the present invention, since a positively chargeable charge control agent is added, the build-up of charge due to friction is extremely rapid, and the charging process can be performed at high speed, and there is little change in the amount of charge over time. . As a result, when development should be done with positively charged toner,
For example, when developing an electrostatic latent image formed by a negative charge, or by reversing development of a positive electrostatic latent image formed using a selenium photoreceptor with excellent photoconductivity as a latent image support as in a laser printer. In such cases, it is extremely advantageous for speeding up the copying process and simplifying the developing device.

(2) Excellent fixing properties.

Since polyester resin generally has a low softening point, toners using polyester resin as a binder are characterized by a low temperature required for fixing. The crosslinkable polyester used as a binder in the present invention is obtained from a monomer composition containing a trifunctional or higher polyfunctional component, and has a molecularly branched and crosslinked structure. While preserving the low-temperature fixing properties that are characteristic of polyester resins, the off-cent phenomenon during fixing is less likely to occur. Furthermore, epoxy resin also greatly contributes to lowering the softening point of toner.

Therefore, by fixing the toner image using the hot roller fixing method, which has many advantages, sufficient fixing can be achieved at high speed and with less energy consumption.

(3) Excellent durability against resin.

The crosslinkable polyester and epoxy resin used as the binder in the present invention both have excellent chemical resistance, so that when the toner of the present invention comes into contact with a resin such as a vinyl chloride polymer that is normally used as a storage cover, Furthermore, it is less susceptible to the effects of plasticizers contained in this resin, and therefore can form toner images with good storage stability.

(4) Excellent durability.

The cross-linked polyester and epoxy resin used as the binder in the present invention both have excellent mechanical strength, and by using a blend of these, the toner of the present invention has excellent impact resistance, and therefore can last for a long time. Good images can be formed.

Claims (1)

[Scope of Claims] 1) The binder contains a crosslinkable polyester and an epoxy resin having an epoxy equivalent of 1500 or more, and the content ratio of the epoxy resin is 50 to 95% by weight based on the binder, and A toner characterized in that a chargeable charge control agent is added in a content ratio of 3 to 12% by weight based on the total amount of the toner. 2) The toner according to claim 1, wherein the crosslinkable polyester is obtained by polymerizing a monomer composition containing a trifunctional or higher functional polybasic acid and/or a trifunctional or higher functional polyhydric alcohol. 3) Crosslinkable polyester has 3 to 22 carbon atoms in its side chain.
The toner according to claim 1, having an aliphatic hydrocarbon group. 4) The toner according to claim 1, wherein the content of the charge control agent is 4 to 9% by weight.