JPS62195681A - Developer composition for electrophotography - Google Patents

Abstract

PURPOSE:To prevent offsetting without coating an offset preventive liquid and to permit fixing at a lower fixing temp. by using a specific vinyl resin-contg. polyester resin for the essential component of a binder resin. CONSTITUTION:The essential component of the binder resin consists of the vinyl resin-contg. polyester resin contg. the vinyl resin having <=11,000 number average mol.wt. and 50-100 deg.C glass transition temp. at 5-42wt% per 100wt% polyester resin. >=3.0wt% Ethyl acetate insoluble component is incorporated into the vinyl resin-contg. polyester resin to prevent the decrease of the high- temp. offset temp. The value of the hydroxyl value/acid is specified to >=1.2 to lower the lowest fixing temp. and to improve fluidity. The grindability of a toner is improved if the number average mol.wt. of the vinyl resin is <=11,000 but the grindability is not improved if the content of said resin is <5wt% of the polyester resin even if the number average mol.wt. is <=11,000. The deterioration in image quality arises after the formation of the toner if the content exceeds 42wt%.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a developer composition for developing electrostatic images in electrophotography, electrostatic recording, electrostatic printing, and the like.

[Conventional technology and problems]

Conventional electrophotographic methods include uniformly charging a photoconductive insulating layer, then exposing the layer to light, as described in U.S. Pat. An electrical latent image is formed by dissipating the electric charge on the part, and is made visible by attaching a colored, electrically charged fine powder called toner to the latent image (development process). After the visible image is transferred to a transfer material such as transfer paper (transfer process), heating,
It consists of permanently fixing (fixing step) using pressure or other suitable fixing methods.

In this way, toner is used not only in the development process but also in the transfer process.
It must have the functions required in each step of the fixing process.

Generally, toner is subjected to mechanical frictional force due to shearing force and impact force during mechanical operation in a developing device, and deteriorates during copying of tens to tens of thousands of sheets. To prevent such toner deterioration, it is best to use a strong resin with a large molecular weight that can withstand mechanical friction, but these resins generally have a high softening point and are suitable for non-contact fixing methods such as oven fixing and infrared fixing. With radiant fixing, the thermal efficiency is poor, so fixing is not sufficient.Also, since the contact fixing method has good thermal efficiency, even in the widely used heat roller constant fixing method, it is necessary to use the heat roller to achieve sufficient fixing. Not only does this require higher temperatures, which can cause problems such as deterioration of the fixing device, curling of paper, and increased energy consumption, but the use of such resins has poor pulverization properties, so when manufacturing toner, manufacturing Efficiency is significantly reduced.

Therefore, it is not possible to use a binder resin whose polymerization degree and even softening point are too high. On the other hand, in the heat roller fixed fixing method, the heating roller surface and the toner image surface of the sheet to be fixed are in pressure contact, so the thermal efficiency is extremely high and it is widely used from low speeds to high speeds. Upon contact, a so-called offset phenomenon tends to occur, in which toner adheres to the surface of the heating roller and is transferred to subsequent transfer paper or the like. In order to prevent this phenomenon, the surface of the heating roller is treated with a material with excellent mold release properties such as a fluorine-based resin, and in addition, a mold release agent such as silicone oil is coated on the surface of the heating roller.

However, the method of applying silicone oil or the like is not preferable because the fixing device becomes large and not only expensive but also complicated, which tends to cause trouble.

Also, Japanese Patent Publication No. 55-6895, Japanese Patent Publication No. 56-98202
As described in the above publication, there is a method of improving the offset phenomenon by widening the molecular weight distribution width of the binder resin, but generally the degree of polymerization of the resin increases and the fixing temperature used also needs to be set high.

As a further improved method, as described in Japanese Patent Publication No. 57-493, Japanese Patent Application Laid-Open No. 50-44836, and Japanese Patent Application Laid-open No. 57-37353, the off-set throat phenomenon is improved by making the resin asymmetrical and crosslinking. There is a way to do this, but the fixation point has not been improved.

Generally, the minimum fusing temperature is between the low temperature offset and the high temperature offset, so the usable temperature range is between the minimum fusing temperature and the high temperature offset.The minimum fusing temperature should be lowered as much as possible, and the temperature at which high temperature offset occurs should be raised as much as possible. This makes it possible to lower the usable fixing temperature and widen the usable temperature range, resulting in energy savings, high-speed fixing, and prevention of paper curl.

In addition, in order to be able to make double-sided copies without any trouble, the copiers have become more intelligent, the temperature control of the fixing device has become more accurate, and
There are many advantages such as relaxing the tolerance range.

Therefore, resins and toners with good fixing properties and offset resistance are always desired.

When using a styrene-based binder resin to meet such requirements, Japanese Patent Application Laid-Open Nos. 49-65232 and 1977-
As described in No. 28840 and JP-A No. 50-81342, a method of adding paraffin wax, low molecular weight polyolefin, etc. as an anti-offset agent is known, but if the amount added is small, there is no effect, and if there is a large amount, the developer It has also been confirmed that the deterioration of

Polyester resin inherently has good fixing properties, and can be sufficiently fixed even in a non-contact fixing method, as described in U.S. Pat. It was difficult to use.

As described in JP-A-50-44836, JP-A-57-37353, and JP-A-57-109875, polyester resins with improved anti-offset properties using polyhydric carboxylic acids have sufficient properties for use. There is a problem in that either they do not have anti-offset properties, or those that do do so at the expense of the low-temperature fixing properties that polyester resins inherently have. On the other hand, toners using polyester resins may have poor fluidity compared to styrene-based toners, and may become agglomerated, resulting in poor toner transportability within the developing device.
Developability may deteriorate, resulting in formation of visible images with poor image quality, such as image unevenness and background smearing.

In order to improve the fluidity of toner, a large amount of fluidity improver such as hydrophobic silica fine powder is added, but as a result, the surface of the electrostatic image support is cleaned using a urethane rubber blade or the like. If the blade is used, toner particles may become trapped between the blade and the electrostatic image support, resulting in poor cleaning and smearing of the visible image.
In addition, when using an image forming apparatus that has a recycling system in which toner that has been developed but has not been transferred is returned to the developing device for reuse, fine particles of hydrophobic silica are embedded in the surface of the toner particles. The fluidity of the liquid was reduced and a visible image of poor quality could be formed.

The present invention has been made to meet these demands, and its purpose is to provide a developer that can prevent offset without applying an anti-offset liquid in a heat roller fixed fixing method, and that can be fixed at a lower fixing temperature. The goal is to provide the following.

Another object of the present invention is to provide a developer that has good fluidity, does not cause blocking, and has a long life (hard to deteriorate).

A further object of the present invention is to provide a resin and a toner with good pulverizability.

[Means for solving problems]

That is, the present invention provides an electrophotographic developer composition containing a binder resin, a colorant, and other additives as desired, in which the main component of the binder resin has a number average molecular weight of 11,000.
5 to 42% by weight of a vinyl resin with a glass transition temperature of 50 to 100°C based on the polyester resin.
Consisting of polyester resin containing vinyl resin,
When the vinyl resin-containing polyester resin has an ethyl acetate insoluble content of 3.0% by weight or more, and the vinyl resin-containing polyester resin has an acid value of AV and a hydroxyl value of OHV, 0f(V/AV The invention relates to an electrophotographic developer composition characterized in that the value of is 1.2 or more.

By using a toner obtained by a known method using the vinyl resin-containing polyester resin of the present invention as the main component of the binder resin, the binder resin contains a high molecular weight component that is insoluble in ethyl acetate above a certain level. Therefore, in addition to the effects of polyester resin, the high temperature offset generation temperature is high.
The non-offcent region can be widened.

On the other hand, unless a transesterification reaction or a reaction with a monovalent carboxylic acid or alcohol is carried out, carboxyl groups or hydroxyl groups remain at the molecular ends of polyester resins, but the amount of triboelectrification of the polyester resin itself depends on the amount of these end groups. It is confirmed that this will change. Terminal group amount,
In particular, if the acid value is reduced too much, the amount of charge of the polyester resin will decrease, and if the amount of terminal groups, especially the acid value, is increased too much,
The amount of charge on polyester resin increases up to a certain level,
On the other hand, the environmental dependence after forming into a toner becomes significant, making it difficult to use it as a developer composition. Acid value 5-60 (KOHmg
/g) is often used for toners. Now, the acid value of polyester resin is AV.

When hydroxylization is OHV, the value of OHV/AV is 1
．． Toners made of polyester resins with a polyester resin of 2 or more have better fluidity, although the reason is not strictly clear.
Furthermore, by using this toner, it became possible to lower the minimum fixing temperature.

The polyester moiety in the resin used as the main component of the binder resin in the present invention is obtained by condensation polymerization of alcohol and carboxylic acid, carboxylic acid ester, or carboxylic acid anhydride. , diethylene glycol, triethylene glycol, l,2-propylene glycol, 1°3-propylene glycol, 1,4-butanediol,
Neopentyl glycol, 1,4-butynediol, 1
．． Diols such as 5-bentanediol and 1,6-hexanediol, bisphenol A, hydrogenated bisphenol A1 polyoxyethylated bisphenol A1
Etherified bisphenols such as polypropylenated bisphenol A, other dihydric alcohols, sorbitol, 12,3.6-hexanetetrol, 1°4-
Sorbitan, pentaerythritol, dipentaerythritol, tripentaerythritol, 1,2.4-butanetriol, L2.5-pentanetriol, glycerol, 2-methylpropanetriol, 2-methyl-
Examples include 1,2,4-butanetriol, trimethylolethane, trimethylolpropane, L3.5-1-lyhydroxybenzene, and other trihydric or higher polyhydric alcohols.

In addition, examples of carboxylic acid components include maleic acid, fumaric acid, citraconic acid, itaconic acid, glutaconic acid,
Phthalic acid, isophthalic acid, terephthalic acid, cyclohexanedicarboxylic acid, succinic acid, adipic acid, cepatic acid,
Azelaic acid, malonic acid, alkenylsuccinic acids such as n-dodecenylsuccinic acid, n-dodecylsuccinic acid, or alkylsuccinic acids, anhydrides of these acids, lower alkyl esters, other divalent carboxylic acids, and 1. 2.4-benzenetricarboxylic acid, 1,2.5-benzenetricarboxylic acid, 2.5.7-naphthalenetricarboxylic acid, L2,4-naphthalenetricarboxylic acid, L2
, 4-butanetricarboxylic acid, 1,2.5-hexanetricarboxylic acid, 1,3-dicarboxyl-2-methyl-
2=methylenecarboxypropane, °tetra(methylenecarboxyl)methane, 1,2,7.8-octanetetracarboxylic acid, Empol trimer acid, and their anhydrides, lower alkyl esters, and other trivalent or higher carboxylic acids Mention may be made of acids.

It is desirable that the above trifunctional or higher polyfunctional monomer component be contained in a proportion of 5 to 60 mol % in each of the alcohol component or acid component as a structural unit in the polymer.

The vinyl resin-containing polyester resin used in the present invention has an ethyl acetate insoluble content of 3.0% by weight or more. The ethyl acetate-insoluble content herein refers to the content that does not pass through a filter paper when a sample is dissolved in ethyl acetate, and can be determined as follows.

Grind the resin sample with a coffee mill, accurately weigh 5,000g of the sample that has passed through a 40-mesh sieve, and place it in a container with a capacity of 150ml together with 10.000g of the filter aid Radiolite (+1700), which has been accurately weighed in advance. 100 ml of ethyl acetate was added into the container, rotated on a ball mill stand for 3 hours, and then allowed to stand for 2 hours. A filter paper (N12) is set in a filter, the supernatant liquid in the container is filtered under reduced pressure, and 100 ml of ethyl acetate is added to the undissolved residue on the filter paper to wash it.

Next, 50 ml of ethyl acetate was added to the undissolved residue in the container, poured into the filter, filtered under reduced pressure, and then the container was
Thoroughly wash with 0 ml of ethyl acetate and pour into a filter until there is no insoluble residue left in the container. After performing vacuum filtration, the undissolved residue was transferred to a Petri dish A (g) that had been accurately weighed in advance, and 11 g was placed at a temperature of 80°C and a pressure of 60 mm.
After drying for 7 hours under the conditions of demand.

Ethyl acetate insoluble content (%) = The above-mentioned ethyl acetate insoluble content can be easily obtained by adding an appropriate crosslinking agent in the polycondensation reaction described above.

In the present invention, a vinyl resin-containing polyester resin having an ethyl acetate insoluble content of 3.0% by weight or more, preferably 3.0 to 30.0% by weight in order to maintain fixability, is bound...the main component of the fat. However, a toner obtained using a polyester resin containing a vinyl resin having an ethyl acetate insoluble content of less than 3.0% by weight lowers the temperature at which high-temperature offset occurs.

In addition, the acid value and hydroxyl value of the resin are measured by the method specified in JIS K 0070, but if the ethyl acetate insoluble content is 3.0% by weight or more, it is preferable to use dioxane as the acid value measurement solvent. .

In the present invention, when the acid value is AV and the hydroxyl value is OIIV, a vinyl resin-containing polyester resin having an OHV/AV value of 1.2 or more is used as the main component of the binder resin.
Toners obtained using resins with an HV/AV value of less than 1.2 have a higher minimum fixing temperature than toners obtained using resins with an HV/AV value of 1.2 or more, and in addition, have poor fluidity and do not have sufficient In order to obtain fluidity, it is necessary to add a large amount of fluidity improver such as hydrophobic silica fine powder, and in this case, as described above, visible images with poor image quality are often formed.

The vinyl-based resin-containing polyester resin having an OHV/^V value of 1.2 or more as described above can be easily obtained by using a larger number of functional groups in the alcohol component than in the carboxylic acid component in the polycondensation reaction described above. It will be done.

Further, in the present invention, if the vinyl resin contained in the binder resin has a number average molecular weight of 11,000 or less, it is possible to improve the crushability of the binder resin and thus the toner.

To mix polyester resin and vinyl resin, for example, there is a method of dissolving them in a common solvent, mixing them, and then distilling off the solvent. It is preferable to add the polyester raw material monomers below and proceed with the reaction because the vinyl resin can be dispersed well. However, if the two resin powders are mixed together to form a toner, the image quality may be adversely affected, such as a decrease in image density or the occurrence of background smudges, so the temperature of the powders is unfavorable.

Furthermore, even if a vinyl resin with a number average molecular weight exceeding ii or ooo is used, it is not effective in improving the crushability of the binder resin. On the other hand, if it is less than 5% by weight, it is not effective in improving the crushability, and if it exceeds 42% by weight, it causes a decrease in image quality after forming into a toner, which is not preferable.

Typical monomers used to form vinyl resins include styrene, 0-methylstyrene, m-methylstyrene, p-methylstyrene, alpha-methylstyrene, p-ethylstyrene, 2,4- Ethylenically unsaturated monoolefins such as dimethylstyrene, p-chlorostyrene, vinylnaphthalene, such as ethylene, propylene, butylene, isobutylene, etc., such as vinyl chloride, vinyl bromide,
Vinyl esters such as vinyl fluoride, vinyl acetate, vinyl propionate, vinyl formate, vinyl caproate, etc., such as acrylic acid, methyl acrylate, ethyl acrylate, n-propyl acrylate, isopropyl acrylate,
n-butyl acrylate, isobutyl acrylate, tert-butyl acrylate, amyl acrylate, cyclohexyl acrylate, n-octyl acrylate, isooctyl acrylate, decyl acrylate, lauryl acrylate, 2-ethylhexyl acrylate, acrylic acid Stearyl, methoxyethyl acrylate, 2-hydroxyethyl acrylate, glycidyl acrylate, 2-chloroethyl acrylate, phenyl acrylate, methyl α-chloroacrylate, methacrylic acid, methyl methacrylate, ethyl methacrylate, n-methacrylate Propyl, isopropyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, tert-butyl methacrylate, amyl methacrylate, cyclohexyl methacrylate, n-octyl methacrylate, isooctyl methacrylate, decyl methacrylate, lauryl methacrylate, methacrylate Ethylene monocarboxylic acids and their esters such as 2-ethylhexyl acid, stearyl methacrylate, methoxyethyl methacrylate, 2-hydroxyethyl methacrylate, glycidyl methacrylate, phenyl methacrylate, dimethylaminoethyl methacrylate, diethylaminoethyl methacrylate, etc. , for example, substituted ethylenic monocarboxylic acids such as acrylonitrile, methacrylonitrile, acrylamide, etc., ethylenic dicarboxylic acids such as dimethyl maleate and substituted products thereof, vinyl ketones such as vinyl methyl ketone, etc., such as vinyl methyl ether, etc. Examples include vinyl ethers such as vinylidene halogen 11, such as vinylidene chloride, and N-vinyl compounds such as N-vinylpyrrole, N-vinylpyrrolidone, and the like.

Further, known crosslinking agents such as divinylbenzene can also be used.

A vinyl resin is obtained by addition polymerizing the above monomers, but preferably a radical polymerization method is used, and in order to reduce the number average molecular weight to 11,000 or less, a large amount of polymerization initiator is used, This can be easily achieved by using a chain transfer agent.

Furthermore, the glass transition temperature of the vinyl resin in the present invention is 5
The temperature is preferably 0 to 100°C, and if it is less than 50°C, it will adversely affect the storage stability of the toner, and if it exceeds 100°C,
Adversely affects fixation.

On the other hand, for the same reason, the glass transition temperature of the binder resin in the present invention is preferably 50 to 80°C.

A toner is obtained by using the vinyl resin-containing polyester resin according to the present invention as the main component of the binder resin, but when preparing the toner, in addition to a colorant, a charge control agent and a magnetic substance as necessary, an offset preventive agent is added. Properties improving agents such as wax as a fluidity improver and hydrophobic silica as a fluidity improver are added. However, when the vinyl resin-containing polyester resin according to the present invention is used as a binder resin, the properties improving agent is not added (but It is good, and even if it is added, the amount added can be small.

Colorants used in the present invention include carbon black, acetylene black, phthalocyanine blue, permanent brown FC, brilliant first scarlet, pigment green B10-damin-B base,
Examples include Solvent Red 49, Solvent Red 146, Solvent Blue 35, and mixtures thereof, and are usually used in an amount of about 1 to 15 parts by weight per 100 parts by weight of the binder resin.

When making a magnetic toner using the binder resin according to the present invention,
Examples of the magnetic material include powders of ferromagnetic metals such as iron, cobalt, and nickel, and alloys or compounds containing ferromagnetic elements such as ferrite, hematite, and magnetite, and the magnetic material has an average particle size of 0.1 It can be used by dispersing about 40 to 70 parts by weight in a binder resin in the form of a fine powder of ~1 μm.

〔Example〕

Examples of manufacturing the binder resin and examples of the present invention will be described below, but the present invention is not limited to these examples.

It should be noted that all composition ratios shown in the production examples and examples are expressed in parts by weight.

Production Example 1 Consisting of 84 parts of styrene and 16 parts of 2-ethylhexyl acrylate, glass transition temperature 62°C, number average molecular weight 8.0
00 styrene-acrylic resin 200g.

Polyoxypropylene (2,2)-2,2-bis(4-
551 g of hydroxyphenyl)propane, 463 g of polyoxyethylene(2)-2,2-bis(4-hydroxyphenyl)propane, and 191 g of fumaric acid.

1.2.168 g of 4-benzenetricarboxylic acid, and 1
．． 5 g of hydroquinone was placed in a 21-inch glass four-bottle flask, equipped with a thermometer, a stainless steel stirring bar, a falling condenser, and a nitrogen inlet tube, and the mixture was stirred at 200°C under a nitrogen stream in a mantle heater. Made me react. The degree of polymerization was monitored from the softening point according to ASTM E 28-51T, and the reaction was terminated when the softening point reached 130°C. The resulting resin was a pale yellow solid, and the DSC
The glass transition temperature measured by a differential calorimeter was 64°C. In addition, the ethyl acetate insoluble content of the resin is 4.2% by weight, the acid value is 15KO) 1mg/g, and the hydroxyl value is 26KOHmg.
/g.

This resin is referred to as a binder resin (1).

Production Example 2 75 parts of styrene, 25 parts of 2-ethylhexyl methacrylate
glass transition temperature 64°C, number average molecular weight ft1
0,500 styrene-acrylic resin 450 g, polyoxypropylene (2,2)-2,2-bis(4-hydroxyphenyl)propane 1050 g 1 succinic acid 19
4 g, and 1,2,5-benzenetricarboxylic acid 157
Using the same equipment and procedure as in Production Example 1, a softening point of 130°C, a glass transition temperature of 67°C, ethyl acetate insoluble content of 3.4% by weight, an acid value of 14KOHmg/g, and a hydroxyl value of 24.
A polyester resin containing mg KOH/g was obtained.

This resin is referred to as a binder resin (2).

Production Example 3 250 g of a styrene-acrylic resin with a glass transition temperature of 62°C and a number average molecular weight of 19,500, consisting of 84 parts of styrene, 16 parts of 2-ethylhexyl acrylate, and 0.2 parts of divinylbenzene, polyoxypropylene (2, 2)
-2,2-bis(4-hydroxyphenyl)propane 578g, polyoxyethylene(2)-2,2-bis(4-hydroxyphenyl)propane L 76g,
72g of trimethylolpropane 480g of terephthalic acid
, and 3 g of diptyltin oxide using the same equipment and procedure as in Production Example 1, a softening point of 130°C, a glass transition temperature of 64°C, an ethyl acetate insoluble content of 5.1% by weight, and an acid value of 17 KO.
A polyester resin having a hydroxyl value of 24 KOIImg/g and a hydroxyl value of 24 KOIImg/g was obtained. This resin is referred to as a binder resin (3).

Production Example 4 In the same manner as Production Example 1 except that the styrene-acrylic resin was removed, the softening point was 130°C and the glass transition temperature was 64°C.
°C, ethyl acetate insoluble content 5.0% by weight, acid value 17KOHm
g/g and a hydroxyl value of 30 KOf+mg/g was obtained. This resin is referred to as a binder resin (4).

Production Example 5 In the same manner as Production Example 1, except that the amount of 1,2.4-benzenetricarboxylic acid was changed to 189 g, the softening point was 1.
30°C, glass transition temperature 65°C, ethyl acetate insoluble content3.
8% by weight, acid value 17KOHmg/g, hydroxyl value 18K
A polyester resin of OII mg/g was obtained. This resin is referred to as a binder resin (5).

Production Example 6 In the same manner as Production Example 3, except that the amount of terephthalic acid was changed to 500 g, the softening point was 130°C, the glass transition temperature was 65°C, the ethyl acetate insoluble content was 4.5% by weight, and the acid value was 19KO.
) 1mg7g of polyester resin having a hydroxyl value of 18KOHmg/g was obtained. This resin is referred to as a binder resin (6).

Production Example 7 In Production Example 1, the reaction was terminated when the softening point reached 105°C, glass transition temperature 62°C, ethyl acetate insoluble content 0% by weight, acid value 19KO) 1mg/g, hydroxyl value 34KO
) Img/g of polyester resin was obtained. This resin is referred to as a binder resin.

Production Example 8 In Production Example 1, except that the styrene-acrylic resin was changed to a styrene-acrylic resin with the same composition and a number average molecular weight of 13,000, the softening point was 130°C and the glass transition temperature was 64°C. , 4.3% by weight of ethyl acetate insoluble matter,
Acid value 16KOHmg/g, hydroxyl value 27KOi1mg
/g of polyester resin was obtained. The resin is bound to a binder resin (
8).

Regarding the binder resins obtained in Production Examples 1 to 8 above, the crushability of the resins was evaluated using the following method, and the results are shown in Table 1.

Simple pulverization test> The resin that has undergone the normal pulverization process is passed through a sieve to obtain a resin powder that passes through 16 sieves but does not pass through 20 sieves. Precisely weigh 30.00 g of the above classified resin powder, and mix it with Coffee Mi/L/(HR-2170 manufactured by PHIjPS).
After pulverizing for 15 seconds using a 32-mesh sieve, the weight (A) of the resin that does not pass through is accurately weighed. The following formula % formula % () The residual rate is determined by the amount of resin in t (30,00 g) before grinding with a coffee mill.The above operation is performed three times and averaged, and the average residual rate is 0 to 15.0%. ◎], 15.1-30.
0% (0), 30.1-45.0% [△], 45
．． 1-100% is displayed as [x].

Examples 1 to 3 and Comparative Examples 1 to 6 Materials having the following compositions were mixed in a ball mill, then melted and kneaded in a pressure kneader, cooled, and then subjected to normal pulverization and classification processes to prepare toner with an average particle size of 11 μm. did.

Composition> Example 1 Binder resin + 11 93 parts Example 2 Binder resin (2) 93 parts Carbon blank "Googal 400RJ 7 parts Example 3 Binder resin f3) 93 parts Carbon blank [Googal 400R 47 parts Comparative example 1 Binder resin (4) 93 parts Carbon blank "Googal 400RJ 7 parts Comparative example 2 Binder resin (5193 parts Carbon blank "Googal 400RJ 7 parts Comparative example 3") Binder resin (6193 parts Carbon black "Googal 400RJ 7 parts Comparative example 4") 93 parts of binder resin Carbon blank "Googal 400R 47 parts Comparative Example 5 Binder resin (7193 parts Carbon black "Googal 400RJ 7 parts Polypropylene wax 4 parts [Viscol 550
PJ (manufactured by Sanyo Chemical Co., Ltd.) Binder resin f8) 9
3 parts carbon black "Googal 400RJ 7 parts or more The toners obtained in Examples 1 to 3 were referred to as Toner 1 to Toner 3, respectively, and the toners obtained in Comparative Examples 1 to 6 were referred to as Comparative Toner 1 to Comparative Toner 6, respectively. do.

39g each of the above toners and 1261g of resin-coated iron powder
A commercially available electrophotographic copying machine (the photoreceptor is amorphous selenium, the rotation speed of the fixing roller is 255 mm/sec, the temperature of the heat roller in the fixing device is variable, and the oil coating device is Images were taken using the following image.

The fixing temperature was controlled at 120° C. to 220° C., and the fixing properties and offset properties of the image were evaluated. The results are shown in Table 1.

The minimum fixing temperature here is when the bottom surface is 15mm x 7.5mm.
A load of 500g was placed on a sand eraser, and the image fixed through the fixing machine was rubbed back and forth 5 times. The optical reflection density was measured using a Macbeth reflection densitometer before and after rubbing, and the fixing rate was determined by the following definition. This refers to the temperature of the fixing roller when it exceeds 70%.

Regarding storage stability, each toner was left for 24 hours at 50° C. and 40% relative humidity, and the degree of aggregation was evaluated. The results are also shown in Table 1.

However, Comparative Toner 2, Comparative Toner 3, and Comparative Toner 5 had poor toner fluidity and poor toner conveyance within the developing device, and as a result, image unevenness and background smear occurred from the initial image. For Toners 1 to 3, the minimum fixing temperature was low, the toner transportability was good, and the image quality of visible images was good from the initial stage up to 50,000 sheets.

1 copy of the procedure master's official letter) April 16, 1986

Claims (1)

[Claims] 1. In an electrophotographic developer composition containing a binder resin, a colorant, and other additives as desired, the main component of the binder resin has a number average molecular weight of 11,000 or less and a glass transition temperature of 50 to 100° C., the vinyl resin-containing polyester resin contains 5 to 42% by weight of the polyester resin, and the vinyl resin-containing polyester resin OH
An electrophotographic developer composition having a V/AV value of 1.2 or more. 2. The electrophotographic developer composition according to claim 1, wherein the binder resin has a glass transition temperature of 50 to 80°C.