JPS60252365A - Toner for developing electrostatic charge image - Google Patents

Abstract

PURPOSE:To improve low-temp. fixability, release property, fluidity, durability, etc. by using a polyester resin contg. an insoluble component of chloroform at a high rate as a binder resin and incorporating specific two kinds of release agents in combination into said resin. CONSTITUTION:The polyester resin having >=5wt% insoluble component of chloroform is prepd. by bringing an alcohol component and carboxylic acid component into condensation polymn. under the controlled reaction conditions. Such resin is used as the binder resin. The release agent consisting of the wax having >=20wt% ester component and having <=4 penetration (e.g.; carnauba wax) and the release agent consisting of the alkylene bis-fatty acid amide compd. (e.g.; formula II, formula III) expressed by formula I (R1, R2 are aliphat. hydrocarbon of >=10C; R3, R4 are H, -OCR5; R5 are aliphat. hydrocarbon; n is a positive integer) as well as a colorant, etc. are uniformly dispersed into such resin.

Description

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

[Background of the invention]

For example, in electrophotography, an electrostatic latent image is usually formed by charging and exposing an electrostatic image support such as a photoconductive photoreceptor, and then this electrostatic latent image is transferred to fine particles such as a binder resin. The toner image is developed using a toner containing a colorant and the like, and the resulting toner image is transferred to a support such as transfer paper and then fixed by heating, pressure, etc. to form a visible image.

It is of course preferable to form a visible image via such an electrostatic charge image at high speed, and from this point of view, conventionally, the heat roller fixing method has high thermal efficiency in the fixing process and is advantageous compared to other methods. has been widely adopted.

However, in recent years, there has been a strong demand for even higher speeds, and in order to achieve this, it is essential to increase the speed of toner image fixing.

However, in order to fix toner images at high speed in the hot roller fixing method, the toner used for development is required to have good low-temperature fixability. Need to lower the score. However, if the softening point of the binder resin of the toner is lowered, a part of the toner forming the image will be transferred to the surface of the heat roller during fixing, and this will be transferred again to the transfer paper etc. that is sent next, forming the image. There is a tendency for the so-called offset phenomenon to occur easily. Furthermore, in the heat roller fixing method, in addition to the above-described offset phenomenon, there is a problem in that a so-called wrapping phenomenon occurs in which the transfer paper or the like is adhered to the surface of the heat roller and wrapped around it. This wrapping phenomenon occurs particularly when the temperature of the heat roller is too low.

In order to successfully achieve such high-speed fixing, the toner needs to be capable of low-temperature fixing and have excellent non-offset and non-wrapping properties.

[Prior art]

Divinyl polymers have traditionally been widely used as binders in toners, but in order to obtain non-offset properties in toners that use vinyl polymers as binders, it has been proposed to use high molecular weight polymers. However, high molecular weight vinyl polymers have a high softening point,
Therefore, even if the offset generation temperature is high, it is difficult to obtain a wide fixable temperature range, and a suitable toner cannot be obtained.

On the other hand, polyester resin can be relatively easily obtained in the form of a low molecular weight, so it can be used as a binder to obtain toner with a low softening point, and it can also be used as an interlayer instead of vinyl polymers. Compared to the toner that
When melted, it has good "wetting" to a support such as transfer paper, and can be sufficiently fixed at a lower temperature than toners made of vinyl polymers, which have approximately the same softening point. preferable.

However, toners using polyester resin as an inder usually have a drawback of low offset generation temperature. In order to increase the temperature at which toner offset occurs in response to peeling,
It is effective to include a high molecular weight component in the toner resin (inner resin), but if you try to obtain sufficient non-offset properties in the toner by this means, the resin has a high softening point, so the toner's The minimum temperature required for fixing (hereinafter referred to as "minimum fixing temperature") becomes high, and the advantages of the heat roller fixing method are lost.Of course, it is desirable that this minimum fixing temperature be low.
In addition, in order to achieve the ability to form visible images on both sides of a single sheet of transfer paper, which has become increasingly popular in recent years,
It is necessary that the toner used for development can be fixed at a low temperature.

From the above background, by incorporating a release agent such as polyolefin wax such as polypropylene wax or polyethylene wax into the toner particles, it is possible to lower the minimum fixing temperature and improve non-offset and non-wrapping properties. Measures have been developed to improve this. Such a method allows the toner itself to have low-temperature fixing properties and release properties, and compared to a method in which fixing is performed while applying release oil such as silicone oil to the surface of a heated roller, silicone oil application is less effective. Since no mechanism is required, the structure of the fixing device is simple, and maintenance such as replenishment of silicone oil is not required.

However, in such a method, in order to fully obtain the effect of adding wax, the content ratio of the wax must be increased, and as a result, the fluidity of the powdered toner is reduced. As a result, a good visible image cannot be formed due to a decrease in developability and transferability, and a carrier tends to become agglomerated.Furthermore, a carrier that is mixed with the toner to form a two-component developer; There is a drawback that wax components adhere to the developing sleeve or electrostatic image support, forming a film and contaminating the developing sleeve or the electrostatic image support, thereby impeding its function. In addition, in a glue cycle system for efficient use of toner, that is, a system in which toner that has been subjected to development but did not participate in the formation of a visible image is returned to the developing device and used again for development, the fluidity of the toner is The disadvantage is that the durability is low.

In this way, it is difficult to obtain sufficient low-temperature fixing properties, release properties, and sufficient fluidity in a toner using only one type of release agent, and it is particularly This is extremely difficult when forming images at even higher speeds.

[Purpose of the invention]

The present invention has been made based on the above-mentioned circumstances, and its objects are to have a low minimum fixing temperature, sufficient mold releasability, and, in addition, to have good fluidity and high durability. An object of the present invention is to provide a toner for developing electrostatic images that can form excellent visible images at high speed over many times.

[Structure of the invention]

The above object is to provide a binder resin made of a polyester resin containing 5% by weight or more of chloroform-insoluble matter, a mold release agent such as wax containing 20% by weight or more of an ester component and having a penetration of 4 or less; This is achieved by a toner for developing electrostatic images characterized by containing a release agent such as an alkylene bis fatty acid amide compound represented by the following general formula.

General formula [In the formula, R1 and R2 each have the same or different carbon number 1]
3 and R4d each represent the same or different hydrogen atoms or 10CR5 groups (wherein R5 represents a saturated or unsaturated aliphatic hydrocarbon group). ), and n represents a positive integer.] The present invention will be specifically described below.

In the present invention, a polyester resin having a chloroform-insoluble content of 5 weight or more is used as a binder resin,
A release agent (hereinafter simply referred to as "first release agent") such as a wax containing at least 20% by weight or more of an ester component and a penetration degree of 4 or less together with other necessary toner components in the particles.
Also called a mold release agent. ) and a mold release agent (hereinafter also simply referred to as "second mold release agent") consisting of an alkylene bis fatty acid amide compound represented by the above general formula to prepare a toner for developing an electrostatic image.

The polyester resin used as the binder resin in the present invention is obtained by condensation polymerization of alcohol and carboxylic acid, and the alcohols used include, for example, ethylene glycol, diethylene glycol, triethylene glycol, 1°2-propylene glycol, 1.3
- Diol Ll such as propylene glycol, 1,4-phthanediol, neopentyl glycol, 1,4-butynediol, 4-bis(hydroxymethyl)cyclohexane, and bisphenol A1 Hydrogenated bisphenol A1 Polyoxyethylenated bisphenol A1 Etherified bisphenols such as polyoxypropylenated bisphenol A and other dihydric alcohol monomers can be mentioned.

Examples of carboxylic acids include maleic acid, fumaric acid, mesaconic acid, 7todiconic acid, itaconic acid, curtaconic acid, phthalic acid, isophthalic acid, terephthalic acid, cyclohexanedicarboxylic acid, succinic acid, adipic acid, cepatic acid, Mention may be made of malonic acid, anhydrides of these acids, lower alkyl esters, dimers of luic acid, and other divalent organic acid monomers.

As the polyester resin used in the present invention, it is preferable to use not only a polymer composed only of the above difunctional monomers but also a polymer containing a component composed of trifunctional or higher polyfunctional monomers. Examples of such polyfunctional monomers, such as trivalent or higher polyhydric alcohol monomers, include sorbitol, 1°2.3.6-hexanetetrol, 1.
4-Sorbitan, pentaerythritol, dipentaerythritol, tripentaerythritol, sucrose, 1゜2
．． 4-butanetriol, 1,2.5-pentanetriol, glycerol, 2-methylpropanetriol,
2-Methyl-1,2,4-butanetriol, trimethylolethane, trimethylolepropane, 1131
5-t') hydroxymethylbenzene, and others.

In addition, as the trivalent or higher polyvalent carboxylic acid monomer, for example, 1
, 2.4-benzenetricarboxylic acid, 1゜2.5-benzenetricarboxylic acid, 1,2.4-cyclohexanetricarboxylic acid, 215+7-sil' lenttricarboxylic acid, 1,2.4-naphthalenetricarboxylic acid, 1, 2.4
-butanetricarboxylic acid, 1.2.5-hexanetricarboxylic acid, 1,3-dicarboxyl-2-methyl-2-
Mention may be made of methylenecarboxypropane, tetra(methylenecarboxyl)methane, 1.2,7.8-octanetetracarboxylic acid, embol trimer acid, acid anhydrides thereof, and others.

It is desirable that the above trifunctional or higher polyfunctional monomer component be contained in a proportion of 30 to 80 mol-0 in each of the alcohol component or acid component as a structural unit in the polymer.

The polyester resin used in the present invention has a chloroform-insoluble content of 5% by weight or more.

In particular, the chloroform-insoluble content refers to the content that does not pass through a filter paper when a sample is dissolved in chloroform, and can be determined as follows.

5. Sample powder obtained by finely pulverizing the resin sample and passing it through a 40 mesh sieve. Collect OOf and filter aid Radiolite (S7
00) 5.0Of in a container with a capacity of 150-
100 f of chloroform was poured into this container, and the container was placed on a ball mill stand and rotated for 5 hours or more to sufficiently dissolve the sample in chloroform.

Meanwhile, in the pressure filter, put a filter paper with a diameter of 7 crn (Boiled 2)
5.00 t of Radiolite was precoated uniformly on it, a small amount of chloroform was added to make the filter paper adhere to the filter, and the contents of the container were poured into the filter. Furthermore, the container is thoroughly washed with 100% chloroform and poured into a filter to prevent any deposits from remaining on the walls of the container. After that, close the top lid of the filter and perform filtration. Filtration is performed under pressure of 4 kg/cm2 or less,
After the outflow of chloroform has stopped, add 100% new chloroform to wash the residue on the paper, and pressurize again.
do something wrong

After the above operations are completed, the filter paper, the residue on it, and the radiolite are all placed on aluminum foil and placed in a vacuum dryer, at a temperature of 80~ioo, °C, and a pressure of 100 m.
After drying under Hg conditions for 10 hours, the total weight a(1) of the dried product thus obtained was measured, and the cycloform insoluble content X (% by weight) was calculated according to the following formula.

X (wt%) Sampling weight (s, ooy) In the case of polyester resin, the chloroform-insoluble content determined in this way is a high molecular weight polymer component or a crosslinked polymer component, and its molecular weight is approximately 20.
It is thought that it is 0,000 or more.

The above-mentioned chloroform-insoluble components can be controlled to a considerable extent by appropriately selecting the reaction conditions or by making an appropriate crosslinking agent exist in the reaction system in the polymerization reaction between alcohol and carboxylic acid mentioned above. It can be formed at the same ratio.

In the present invention, the chloroform insoluble content is 5% by weight.
The above polyester resin is used as a binder, but if a polyester resin containing less than 5% by weight of chloroform-insoluble matter is used, the resulting toner will have a low offset generation temperature.

The first mold release agent contained in the toner of the present invention contains an ester as one component, and the content thereof is 20% by weight or more, and other components include higher fatty acids,
(It may contain higher alcohols, hydrocarbons, etc.) and has a penetration level of 4 or less. Further, it is preferable that this wax has a melting point of 60 to 110'C-.

In the above, the wax penetration is JISK2235-
This refers to the value obtained in accordance with the test method specified in 1980. That is, the sample wax was heated and melted, placed in a sample container, and allowed to cool.Then, the temperature was maintained at a constant temperature of 25°C in a constant temperature water bath, and a needle with a total mass of 10° was vertically inserted into the sample wax. Allow the needle to enter for 5 seconds, measure the depth to which the needle has entered to 0.1 m, and multiply this by 10 to determine the penetration.

Further, the melting point is determined by differential scanning calorimetry (DSC). In other words, several kilograms of samples were heated at a constant heating rate (10°C/
The melting point is the melting peak value when heated at -).

Specific examples of the first mold release agent include those listed in Table 1.

For example, the following structural formula can be cited as a representative example.

1, Cja H2ICO-NH-(CH2)5-NH
-OCC1oH212, cll H23CO-NH-(
CH2)4-NH-occ, 1n263, c13H
27CO-NH-(CI(2)2-NH-0CC15
H274, C1oH21C0-NH-(CH2)s-N
H-OCC14H29s, C15H31C0-NH-
(CH2)2-NH-OCC15H316, C17H5
5Co-NH-CH2-NH-0CC15H317,
c17 H35Co-NH-(CH2)2-NH-oc
c15a618, C23H47Co -NH-CH2
-NH-occ15u3112, C21H41CO-N
H-CH2-NH-0CC21H4113゜14, C17H55CO-NH-(CH2)2- NH
-o5c, 7H3115° Incidentally, examples of commercially available second mold release agents include the following.

“Bisamide” (manufactured by Nippon Hydrogen Industries Co., Ltd.) “Plastflow” (manufactured by Nitto Kagaku Co., Ltd.) “Diamid 200 Bis” (manufactured by Nippon Hydrogen Industries Co., Ltd.) “Lubloon EJ (manufactured by Nippon Hydrogen Industries Co., Ltd.) “Alflow H3O5J (manufactured by Nippon Oil & Fats Co., Ltd.) ) “Alph-
V-60J (manufactured by Bhon Yushi Co., Ltd.) [Amide-6LJ (manufactured by Shuki Fine Chemical Co., Ltd.) "Amide-7SJ (manufactured by Shuki Fine Chemical Co., Ltd.)""Amido-6HJ (manufactured by Shuki Fine Chemical Co., Ltd.)""Armowax-EBSJ (manufactured by Lion Co., Ltd.)" Armor Co., Ltd.) "Hoechst Wax C" (Hoechst Java Co., Ltd.) "Nopco Wax-22DS J (Nopco Chemical Co., Ltd.) - "Adopa Wax-280J (Advance Co., Ltd. M) "Kaohwax-EB J (Kako Soap Co., Ltd.)" Varisin-285J (manufactured by Baker Castor Oil Co., Ltd.) Generally, the second mold release agent has a higher softening point as the number of carbon atoms in the aliphatic hydrocarbon group and the length of the alkylene chain increase. It is desirable that the alkylene chain has a softening point of 100 to 180°C, preferably 130 to 160°C, from the viewpoint of reducing the heating temperature or fixing temperature during production.For this reason, the alkylene chain has 5 or less carbon atoms. Preferably, the length is such that

The content ratio of the mold release agent is such that the sum of the first mold release agent and the second mold release agent is 1 to 20. The amount is within a range of 1 to 10% by weight, preferably 1 to 10% by weight. If this proportion is less than 1% by weight, the effect as a release agent is not exhibited, so the non-offset property of the toner is not improved, and the effect of lowering the minimum fixing temperature cannot be obtained.

On the other hand, if it exceeds 20% by weight, the fluidity of the toner will decrease, resulting in poor developability and transferability, resulting in a failure to form a good visible image, and may also cause damage to the developing sleeve or electrostatic image support. The mold release agent adheres and forms a film, which inhibits its function.

Further, the content ratio of the first mold release agent and the second mold release agent is preferably 1:0.5 to 10 in weight ratio, particularly preferably 1:0.5 to 5. If the amount of the second release agent is too small, the fluidity of the toner tends to decrease, and if the amount of the first release agent is too small, the low-temperature fixing properties and release properties of the toner tend to be insufficient. .

The toner of the present invention includes the above-mentioned first mold release agent and second mold release agent together with other toner components added as necessary, such as a colorant, a magnetic substance, a property improver, etc. The powder is dispersed in a binder resin, and its average particle size is usually in the range of 5 to 30 microns. Further, a toner may be constituted by further adding and mixing a fluidity improver such as fine silica powder to the powder or granules thus obtained.

As a coloring agent, carbon black, nigrosine dye (
C,1,A 50415B), Aniline Blue (C,1
, A 50405), Calco Oil Blue (C, I.

Azoec Blue 3), Chrome Yeo-
(C, 1, A14090), Ultramarine Blue (C
, 1, A77103), DuPont Oil Red (C,
1, 26105), quinoline yellow (C, 1, black 47005), methylene blue chloride (C1I-A
52015), Phthalocyanine Blue (C,1,A7
4160), malachite green oxalay) (C
, 1, A 42000), lamp black (C, I,
A7266), Rose Bengal (C,1,A454
35), 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 added in an amount of 1 to 20 parts by weight per 100 parts by weight of the binder resin. Ru.

The magnetic material may be a ferromagnetic metal or alloy 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 is subjected to appropriate heat treatment. Examples include alloys which exhibit ferromagnetic properties due to the use of metals, such as 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. The content thereof is 20 to 70 parts by weight, preferably 40 to 70 parts by weight per 100 parts by weight of toner.
It is 70 parts by weight.

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

The toner of the present invention is mixed with a carrier composed of iron powder, glass beads, etc. to form a two-component developer, but when it contains a magnetic material, it can be directly used as a one-component developer to develop electrostatic images. Ru.

〔Effect of the invention〕

As described above, in the toner of the present invention, the binder resin is made of a polyester resin containing a high molecular weight component that is insoluble in chloroform above a certain level, and the toner has a first mold release agent as described above and a second mold release agent. As it is clear from the description of the examples below, it has a low minimum fixing temperature, sufficient mold release properties, and excellent non-offset properties. It provides non-wrapping properties, good fluidity, and high durability.As a result, it is possible to produce excellent visible images with high image density without the occurrence of offset and wrapping phenomena at low fixing temperatures. Moreover, it can be stably formed many times at an even higher speed. Even when subjected to the development process in a recycling system, it has excellent durability and can stably obtain the above characteristics, and contamination of the carrier, electrostatic image support, and developer sleeve by toner is significantly reduced. Become.

Although the reason why the toner of the present invention has such excellent properties as described above has not been strictly elucidated, it is believed that the following is a part of the reason.

- The binder resin itself has non-offset properties and can be fixed at low temperatures.

■The toner contains not only one type of release agent, but also both the first release agent and the second release agent, which have different characteristics. If the releasability required for the toner is obtained only by using a second release agent, the fluidity will be greatly reduced, and if the low-temperature fixing property required for the toner is obtained only by the second release agent, the releasability will be significantly reduced. As a result, the drawback that each mold release agent alone causes a large decrease in mold properties does not appear in this case, and the favorable effects of each of the first mold release agent and the second mold release agent are fully exhibited. To make it possible to stably obtain excellent low-temperature fixing properties, high mold release properties, and high fluidity in a toner for a long period of time.

■Moreover, the first mold release agent has a penetration degree of 4 or less and is itself hard and highly durable, which causes problems such as decreased fluidity especially when used in a recycling system. There is no deterioration in properties, and since the first release agent is hard, the surface of the toner has high smoothness and fixing properties are improved.

Furthermore, although the toner of the present invention contains a release agent, it has good fluidity, so it is not necessary or necessary to add a fluidity improver such as hydrophobic silica fine powder. Even in cases where hydrophobic silica fine powder is used, it is sufficient to add only a small amount of it; therefore, adding a large amount of hydrophobic silica fine powder may cause harmful effects, such as electrostatic charge image due to high hardness. Problems such as damage to the surface of the support will not occur.

[Embodiments of the invention]

Examples of the present invention will be described below, but the present invention is not limited thereto. Note that "1 part" represents parts by weight.

The binder resin and mold release agent used in the following examples are as follows.

[Binder resin]

1) Binder resin A terephthalic acid 2991 and polyoxypropylene (2,
2) 211 tons of -2,2-bis(4-hydroxyphenyl)furopane and 829 pentaerythritol were placed in a round-bottomed flask equipped with a thermometer, a stainless steel stirrer, a glass nitrogen gas inlet tube, and a down-flow condenser. Place the flask in a mantle heater, introduce nitrogen gas through the nitrogen gas inlet tube to raise the temperature while keeping the inside of the flask in an inert atmosphere, and add 0.05F of diptyltin oxide. Polyester resin with a chloroform-insoluble content of 17% by weight and a softening point of 131°C obtained by reacting at a temperature of 200°C while monitoring the reaction at the softening point [Release agent] 1) Mold release agent al (first mold release agent) ) ``Carnauba wax A I J (manufactured by Noda Fuchs Co., Ltd.) 2) l1lIt mold agent a2 (first mold release agent) ``Candelilla wax A2'' (manufactured by Noda Wax Company) 3) mold release agent b1 (second mold release agent) Mold release agent) "Hoechst Wax C" (manufactured by Hoechst Japan Co., Ltd.) 4) Mold release agent b2 (second mold release agent) "Bisamide" (manufactured by Nitto Kagaku Co., Ltd.) 5) Mold release agent C' (for comparison) [ Viscol 660PJ (manufactured by Jojo Kasei Co., Ltd., low molecular weight polypropylene wax) In each of the Examples and Comparative Examples, the materials with the indicated formulations were placed in an extruder set at a temperature 10°C lower than the softening point of the binder resin. A toner powder consisting of particles with an average particle size of 11 μm was obtained by a method of mixing, cooling (water cooling), pulverizing, and classifying, and to this was added 0.8% by weight of hydrophobic silica fine powder. A toner was produced.

Example 1 Binder resin A 100 parts Mold release agent al 2 Molding agent b1 2 parts Carbon black "Mogul L" (manufactured by Cabot)
10 parts Example 2 Contains binder resin 100 parts Release agent a1 Type 2 formulation agent b1 6 parts Carbon black "Mogal L" 10 parts Example 3 Binder resin A 100 parts Release agent, 2 Type 2 formulation agent b2 2 Part carbon black "Mogal L" 10 parts Comparative example 1 Binder resin A 100 parts fIa type agent al 2 parts Carbon black "Mogal L" 10 parts Comparative example 2 Binder resin A I00 parts Release agent at 4 parts Carbon black "Mogal L ” 10 parts Comparative Example 3 Binder resin A 100 parts Mold release agent BL 2 parts Carbon black “Mogul L” 10 parts Comparative example 4 Binder resin A 100 parts Mold release agent BL 4 parts Carbon blank “Mogul L” 10 parts Comparative example 5 Binder resin A 100 parts Release agent d 4 parts Carbon black "Mogul L" 10 parts Comparative example 6 Binder resin A 100 parts Carbon black "Mogul L" 10 parts or more Toner obtained in Examples 1 to 3 "Toner 1" each
~ "Toner 3" and the toners obtained in Comparative Examples 1 to 6 were respectively designated as "Comparative Toner 1" to "Comparative Toner 6", and each of these toners was evaluated as having high fluidity as an index of fluidity. Taking advantage of the small degree of compression of powder and granular material, it is placed in a container with a diameter of 28+m and a volume of 100-m from above.
The sample was loosely packed through a Metssie sieve, and the weight was measured to determine the static bulk density.

In addition, each of the above toners is mixed with a carrier made of iron powder coated with resin (to prepare a developer with a toner concentration of 2 weight), and each of the toners is used for electrophotographic copying with a stain toner recycling system. Machine r U-Bix 450
0 J (manufactured by Konishiroku Photo Industry Co., Ltd.) at a temperature of 33°C.
Development of an electrostatic charge image under environmental conditions of relative humidity of 80 degrees,
Actual copying tests were conducted 60,000 times using the steps of transferring the toner image to transfer paper and fixing the toner image using a heat roller fixing device, and the initial image density of the resulting copied image and the image density after 60,000 copies were determined. was measured. In addition, the bulk density of each toner after 60,000 copies was measured. After 60,000 copies, the degree of toner contamination on the surface of the carrier, the surface of the photosensitive drum, and the surface of the developing sleeve was examined.

Furthermore, for each toner, the minimum fixing temperature, offset occurrence temperature (measured only for Toners 1 to 3), and wrapping occurrence temperature were determined.

Regarding the minimum fixing temperature, we used a heat roller whose surface layer was made of Teflon (polytetrafluoro-tetraethylene manufactured by DuPont) and a pressure roller whose surface layer was made of silicone rubber "rKE-1300T" (manufactured by Shin-Etsu Chemical Co., Ltd.). The toner image of the sample toner transferred to the transfer paper of 64 f/m2 is fixed at a high linear speed of 200 m/s using a fixing device consisting of a heat roller set at 100°C. Kimwipe rubbing was applied to the formed fixed image repeatedly at each temperature raised stepwise by 5° C., and the lowest setting temperature for a fixed image exhibiting sufficient rubbing resistance was defined as the lowest fixing temperature. Note that the fixing device used here does not have a silicone oil supply mechanism.

In addition, to measure the offset occurrence temperature, the toner image is transferred and fixed to the above-mentioned fixing device, and then a blank transfer sheet is sent to the fixing device under the same conditions. The operation of observing whether or not toner stains occur was repeated while the set temperature of the heat roller of the fixing device was successively increased, and the temperature at which offset occurred was determined.

In addition, using a so-called solid black original, the operation of fixing the toner on almost the entire surface of the transfer paper was carried out by sequentially lowering the set temperature of the heat roller of the fixing device in accordance with the measurement of the offset occurrence temperature described above. (repeatedly) to determine the temperature at which winding occurs.

The results are shown in Table 2.

As is clear from the results in Table 2, according to the toner of the present invention, the offset generation temperature is high and excellent non-offset properties are obtained, and the winding generation temperature is low and excellent non-coiling properties are obtained. In addition, it has a low minimum fixing temperature and excellent low-temperature fixing properties, has good fluidity, is highly durable and retains its excellent properties even after 60,000 copies, has little toner contamination, and, as a result, can be used at high speeds. Excellent visible images can be stably formed over many times.

On the other hand, Comparative Toners 1 and 2 contained only the first releasing agent, and therefore had poor fluidity and image density. Comparative toners 3 and 4 contain only the second release agent, so the minimum fixing temperature is high and the non-wrapping property is poor. According to Comparative Toner 5, the release agent contained was a low molecular weight polypropylene wax;
The minimum fixing temperature and wrapping temperature are high, and contamination with toner is observed, and durability is low. Furthermore, according to Comparative Toner 6, since it does not contain gold as a release agent, the minimum fixing temperature is considerably high, the temperature at which curling occurs is high, and the non-rolling property is poor.

Claims (1)

[Scope of Claims] 1) A binder resin consisting of a polyester resin containing 5 weight or more of chloroform-insoluble content, and a mold release agent consisting of a wax containing 200 weight or more of an ester component and having a penetration of 4 or less. and a release agent made of an alkylene bis fatty acid amide compound represented by the following general formula. A toner for developing an electrostatic image. General formula [wherein R1 and dog have 10 carbon atoms, which are the same or different from each other]
represents a saturated or unsaturated aliphatic hydrocarbon group,
R3 and R4 each represent the same or different hydrogen atom or -0CB5 group (wherein R5 represents a saturated or unsaturated aliphatic hydrocarbon group), and n represents a positive integer. 2) The content ratio of a mold release agent such as a wax containing 20% by weight or more of an ester component and a penetration degree of 4 or less to a mold release agent υ such as an alkylene bis fatty acid amide compound represented by the general formula is The toner for developing an electrostatic image according to claim 1, wherein the ratio is 1:0.5 to 10.