JPH03122662A - Heat fixable and positive chargeable toner - Google Patents

Abstract

PURPOSE:To obtain the heat fixable and positive chargeable toner having good developing and transferring properties and excellent low-temp. fixability and offset resistance by incorporating a crosslinked polyester resin having 0.1 to 10mgKOH/g acid value and a specific org. metal compd. into the toner. CONSTITUTION:The crosslinked polyester resin having 0.1 to 10mgKOH/g acid value and the org. metal compd. contg. bivalent or higher valency metal at 0.1 to 10.0 pts. wt. per 100 pts. wt. resin are incorporated into the toner. Resins which consist of etherified diphenyls and arom. dicarboxylic acids as basic skeleton and contain tervalent or higher valency polycarboxylic acids of 3 to 30mol% per the total monomer component and alkyl-substd. dicarboxylic acids or alkenyl-substd. dicarboxylic acids of 10 to 30mol% per the total monomer component are preferable as the constituting raw material of the polyester resin as the binder resin to constitute the toner. The toner having the good developing and transferring properties and the excellent low-temp. fixability and offset resistance is obtd. in this way.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention is applicable to developing electrostatic latent images in electrophotography or electrostatic printing, and to heat fixing methods such as fixed fixing with a hot roller. The present invention relates to a heat-fixable positively chargeable toner.

[Prior art] As a conventional electrophotographic method, US Pat. No. 2,297°6
Specification No. 91, Japanese Patent Publication No. 42-23910 (U.S. Patent No. 3,666, 363) or Japanese Patent Publication No. 4
No. 3-24748 (U.S. Pat. No. 4,071,361)
A large number of methods are known, such as those described in US Pat. Generally, an electrical latent image is formed on a photoreceptor by various means using a photoconductive substance, and then the latent image is developed using a colored fine powder called toner having an opposite charge. , if necessary, after transferring it to a transfer material such as paper, fixing it by heating, pressure, heat pressure, solvent vapor, etc.
It is for obtaining a copy.

Therefore, toner is used in each process of development, transfer, and fixing.
It must have the required performance. Usually, toner is made of a thermoplastic resin as a binder and a colorant.
If necessary, a charge control agent is blended, melt-mixed under heating, and then pulverized to a predetermined particle size.

In recent years, organic photoreceptors (negatively charged) have been increasingly used as photoreceptors in copying machines, etc., instead of conventional inorganic photoreceptors (positively charged) due to demands for cost, processability, non-pollution, etc. In some cases, conventional inorganic photoreceptors are also installed in laser beam printers that perform reversal development, and there is a desire to develop positively chargeable toners with better developability.

At the same time, in order to meet the demands for faster speeds, energy savings, and cost reductions in copying machines and the like, it is desired that toner be fixed at a lower temperature.

Various methods and devices have been developed for fixing toner on paper, etc., but the pressure contact heating method using a heating member, such as the fixed fixing method using a heated roller, is the most popular method because it is advantageous in terms of thermal efficiency. In this fixing method, efforts are being made to fix the toner at a low temperature.

[Problems to be Solved by the Invention] Conventionally, positively chargeable toners have been produced by adding a positively chargeable charge control agent to a styrene-acrylic copolymer resin that is approximately neutral in terms of charge, or by adding an amino group to the styrene-acrylic copolymer resin, which is approximately neutral in terms of charge. A method has been adopted in which a binder resin is prepared by copolymerizing an acrylic monomer with a styrene monomer. However, at present, it is not possible to obtain a toner that satisfies all of the important properties required for a toner, such as anti-offset properties, anti-blocking properties, and low-temperature fixing properties. On the other hand, polyester resin is attracting attention as a binder resin that satisfies these fixing properties in a well-balanced manner.
60, JP-A-59-9669, JP-A-59-Sho.
Applications using polyester resin as a binder have been filed in JP-A-29256 and the like. Indeed, the polyester resins in these disclosed techniques have a relatively high acid value and are excellent binder resins for use in negatively chargeable toners.

Several studies have been made to use polyester resins with such excellent fixing properties for positively chargeable toners. For this, the acid value is 4K.
A polyester resin having a OHmg/g or less and a hydroxyl value of 20KOHmg/g or less was prepared using JP-A No. 63-148271.
The publication states that when a polyester resin having an acid value of 5 KOHmg/g or less and a hydroxyl value of 60 KOHmg/g or less is used, it can also be used as a binder for positively chargeable toner.

In our study, it is true that the acid value of polyester resin and the amount of negative charge are correlated, and the lower the acid value, the more neutral the charge tends to be.

However, these polyester resins (1) have an acid value of 5;
It is difficult to stably produce a polyester resin having a concentration of mgKOH/g or less, and it is particularly difficult to obtain a crosslinked polyester resin for the purpose of improving offset resistance in a fixing process.

(2) Even if the obtained binder resin has a low acid value, the acid value may increase when various additives such as colorants are blended, heat kneaded, and made into a toner. When polyester is used, this tendency is strong.Therefore, it is difficult to obtain a toner that satisfies fixing properties and developability (as a positively chargeable toner).

In particular, when trying to maintain a low acid value with a crosslinked polyester resin, the viscosity within the reaction system increases rapidly during resin production, making it difficult to stably obtain a product with desired properties. .

In other words, in view of the above circumstances, it is an object of the present invention to provide a heat-fixable, positively chargeable toner that has good development and transfer properties, and is also excellent in low-temperature fixability and offset resistance. It is in.

[Means and effects for solving the problem] The present invention is characterized by using a crosslinked polyester resin having an acid value of 0.1 to 10 mgKOH/g, and 100 parts by weight of the resin.
The present invention provides a heat-fixable positively chargeable toner containing at least 0.1 to 10.0 parts by weight of an organometallic compound containing a divalent or higher valence metal.

The invention also features a heat-fixable, positively chargeable toner in which the temperature at which the crosslinked polyester resin starts flowing out in an elevated flow tester is in the range of 85 to 105°C, and the softening point is in the range of 120 to 150°C, and further, Acid value is 5 mgK
It is also characterized by a heat-fixable positively chargeable toner having an OH/g.

The present invention will be explained in detail below.

In the present invention, the acid value of the toner can be effectively lowered by blending an organometallic compound containing an ionic crosslinkable metal with a valence of 2 or more to the polyester resin having an acid value. The acid value of is 0.1
When the acid value is in the range of 10 mgKOH/g or less, the acid value of the obtained toner can be 5 mgKOH/g or less. When the acid value of the polyester resin used as the binder exceeds lontgKOH/g, it may be difficult to reduce the acid value of the toner to 5 mgKOH/g or less. becomes inferior.

Furthermore, in order to achieve both low-temperature fixing properties and anti-offset properties, after performing esterification or transesterification under reduced pressure during the polymerization process of polyester resin, the reaction system changes as the viscosity of the polymer increases. The pressure is increased to control the crosslinking reaction rate, and by this operation, the outflow start temperature in the elevated flow tester is 85 to 105°C, the softening point is 120 to 150°C, and the acid value is 0.1 to 10 mgK.
A crosslinked polyester resin can be obtained with good reproducibility within the OH/g range without being greatly influenced by the composition of the polymerization components used. When the outflow start temperature exceeds 105° C., the low-temperature fixability of the toner is impaired. Softening point is 120℃
If the value is below , the offset resistance of the toner will be impaired.

Therefore, for example, in the hot roller fixed fixing method, an auxiliary means such as applying oil having mold release properties to the heating member such as the upper roller is required. Polyester resins with a runoff start temperature of less than 85°C and a softening point of 120°C or more can certainly achieve both low-temperature fixing properties and anti-offset properties, but unreacted components remain in the resin, resulting in a rapid increase in acid value. Resin T
This results in a decrease in g, resulting in a problem of deterioration of toner developability and printability.

The glass transition point (Tg) in the present invention is measured using a Perkin-Nilmer DSC-7 at a heating rate of 10°C/min and a sample of 10 mg.
41,! ! -82). As shown in Figure 4, in the DSC curve during the second temperature rise, Tg shall be.

The constituent raw materials of the polyester resin as the binder resin constituting the toner of the present invention have a basic skeleton of etherified diphenols and aromatic dicarboxylic acids, and have a trivalent or higher valence of 3 to 30 m0β% with respect to the Kaneko Tsumar component. of polycarboxylic acids and 10 to 30 mof% of the total monomer components.
Those containing alkyl-substituted dicarboxylic acids or alkenyl-substituted dicarboxylic acids are preferred.

Here, as the etherified diphenols that can be used, polyoxystyrene (6)-2,2-bis(4-hydroxyphenyl)propane, polyhydroxybutylene (2)-2,2-bis( 4-hydroxyphenyl)propane, polyoxyethylene(3)-2,2-bis(4-hydroxyphenyl)propane, polyoxypropylene(3)-bis(4-hydroxyphenyl)thioether, polyoxyethylene(2)- 2,6-dichloro-4-hydroxyphenyl, 2',3',6'-trichloro4'-hydroxyphenylmethane, polyoxypropylene (3)-2-bromo-4-hydroxyphenyl, 4-hydroxyphenyl ether, polyoxyethylene (2,5)-P-P-bisphenol, polyoxybutylene (4) bis(4-hydroxyphenyl)ketone,
Polyoxystyrene (7)-bis(4-hydroxyphenyl)ether, polyoxyethylene (3)-2.2
-bis(2,6-diaiodo-4-hydroxyphenyl)propane and polyoxypropylene (2,2)2,
Examples include 2-bis(4-hydroxyphenyl)propane.

One group of etherified diphenols are the etherified bisphenols. A preferred group of etherified bisphenols are those that are ethoxylated or propoxylated and have 2 to 3 mails of oxyethylene or oxypropylene per moj7 of bisphenol, with R being a propylene or sulfone group. Examples of this group are polyoxyethylene(2,5)-bis(2,6-
dipromo-4-hydroxyphenyl) sulfone, polyoxypropylene (3)-2,2-bis(2,6-difluoro-4-hydroxyphenyl)propane and polyoxyethylene (l·5)-polyoxypropylene (l·
0)-bis(4-hydroxyphenyl)sulfone.

Another preferred group of etherified bisphenols falling into the group characterized by the above formula is polyoxypropylene 2
・2'-bis(4-hydroxyphenyl)propane and polyoxyethylene or polyoxypropylene 2.
2-bis(4-hydroxy, 2,6-dichlorophenyl)propane (the number of oxyalkylene units per unit of bisphenol is 2.1 to 2.5).

In addition, examples of the aromatic dicarboxylic acids that can be used include terephthalic acid, isophthalic acid, phthalic acid,
diphenyl-p'p'-dicarboxylic acid, naphthalene-2
・7-dicarboxylic acid, naphthalene-2,6-dicarboxylic acid, diphenylmethane-p'p'-dicarboxylic acid, benzophenone-4,4'-dicarboxylic acid, 1,2-diphenoxyethane-p'p'-dicarboxylic acid etc. can be used,
Other acids include maleic acid, fumaric acid, glitaric acid, cyclohexanecarboxylic acid, succinic acid, malonic acid, adipic acid, mesaconic acid, citraconic acid, sebacic acid, and anhydrides and esters of these acids. Can be mentioned.

Examples of trivalent or higher polycarboxylic acids include trimellitic acid, pyromellitic acid, cyclohexanetricarboxylic acids,
2,5,7-naphthalenetricarboxylic acid, 1,2,4-
naphthalenetricarboxylic acid, 1,2,4-butanetricarboxylic acid, l,2,5-hexanetricarboxylic acid, l.
3-dicarboxyl-2-methylenecarboxylpropane, l.3-dicarboxyl-2-methyl-2-methylenecarboxylpropane, tetra(methylenecarboxyl)methane, l.2.7.8-octanetetracarboxylic acid and their Examples include anhydrides and esters.

Further, as the alkenyl-substituted dicarboxylic acid or alkyl-substituted dicarboxylic acid, maleic acid substituted with an alkenyl group or alkyl group having 6 to 18 carbon atoms,
Examples include fumaric acid, adipic acid, succinic acid, glutaric acid, sepatic acid, azelaic acid, and anhydrides and esters thereof.

Particularly preferred are n-dodecenylsuccinic acid, indocenylsuccinic acid, n-dodecylsuccinic acid, iso-dodecylsuccinic acid, iso-octylsuccinic acid, n-octylsuccinic acid, n-butylsuccinic acid, and the like.

Further, as a constituent component of the polyester fat used in the toner of the present invention, a polyhydric alcohol component other than etherified diphenols may be used at a molar fraction of 1710 or less in the total alcohol component, such as ethylene Glycol, diethylene glycol, triethylene glycol, 1
．． Diols such as 2-propylene glycol, 1.3-propylene glycol, 1.4-butanediol, neopentyl glycol, 1.4-butenediol, 1.5-bentanediol, 1.6-hexanediol, and other Dihydric alcohol or sorbitol, 1.2.3
．． 6-hexanetetrol, 1,4-sorbitanepentaerythritol, dipentaerythritol, tripentaerythritol, 1.2.4-butanetriol, 1,
2.5-pentanetriol, glycerol, diglycerol, 2-methylpropanetriol, 2-methyl-
Examples include 1,2,4-butanetriol, trimethylolethane, trimethylolpropane, 1,3,5-trihydroxybenzene, and other trihydric or higher polyhydric alcohols.

As the organometallic compound applied to the toner of the present invention,
Examples include organic salts or complexes that combine divalent or higher valence metals. Effective metal species include A2, Ba%Ca%C
d%Cos Crs Cu%Fes Hg, Mg,
Examples include polyvalent materials such as Mn, Ni, Pb, Sn, and Sr%Zn.

Metal complexes include iron (II) acetylacetonate, iron ([) acetylacetonate, aluminum acetylacetonate, beryllium acetylacetonate, manganese (rll) acetylacetonate, copper (II) acetylacetonate, cobalt ( III) Acetylacetonate and the like.

Examples of metal salts include zinc acetate, magnesium acetate, calcium acetate, aluminum acetate, magnesium stearate, calcium stearate, aluminum stearate, and the like.

Other examples include aluminum isopropoxide, aluminum methylate, diorganotin oxides, dehydrated condensates of diorganotin oxides and polyhydric alcohols, and diorganotin borates.

These organometallic compounds have varying degrees of reactivity with the aforementioned low acid value polyester resin, and although it cannot be generally specified, in order to lower the acid value, 0.1 to 10 parts by weight of the resin should be added. It can be contained in the range of .0 parts by weight, and if it exceeds 10 parts by weight, the ionic crosslinking reaction will proceed too much.
It may affect the heat fixability of the toner and impair the low temperature fixability, and if it is less than 0.1 part by weight, the acid value of the toner cannot be effectively lowered. Among these organometallic compounds, iron (II) acetylacetate, magnesium acetate, aluminum isopropoxide, and diorganotin borates are particularly preferred.

Further, these organometallic compounds may themselves have positive charge control properties, and even in such cases, a positively charge control agent may be further blended.

Examples of the positive charge control agent that can be used include electron-donating dyes (for example, nigrosine dyes), alkoxylated amines, quaternary ammonium salts, triphenylmethane dyes, and vinyl polymers having amino groups.

As the colorant that can be used in the present invention, well-known dyes and pigments such as carbon black, iron black, and graphite can be used.As the dye, for example, c, r.

Direct Red 1, C, 1, Direct Red 4, C
,1, Acid Red 1, C,1, Basic Red 1
, C,1, Modern Tread 30, C,1, Direct Blue 1, C,1, Direct Blue 2, C,1, Acid Blue 9, c,r, Acid Blue 15, C,1,
Basic Blue 3, C, 1, Basic Blue 5, C
, 1, Mordand Blue, C, 1, Direct Green 6, C, 1, Basic Green 4, C, 1, Basic Green 6, etc.

Pigments include yellow lead, cadmium yellow, mineral fast yellow, navel yellow, naphthol yellow S1 Hansa Yellow G, and permanent yellow NCG.
, tartrazine lake, red yellow lead, molybdenum orange, permanent orange GTR, pyrazolone orange,
Benzidine Orange G1 Cadmium Red, Permanent Red 4R, Watching Red Calcium Salt, Eosin Lake, Brilliant Carmino 3B, Manganese Purple,
First Violet B, Methyl Violet Lake, Navy Blue, Cobalt Blue, Alkaline Blue Lake, Victoria Blue Lake, Phthalocyanine Blue First Sky Blue, Indan Stremburu-BC, Chrome Green, Chromium Oxide, Pigment Green B, Malachite Green Lake, Fainal There are yellow green G, etc.

When the toner of the present invention is used as a magnetic toner, it is sufficient that the toner contains magnetic fine particles (the magnetic fine particles may be any material that exhibits magnetism or can be magnetized;
There are metals such as iron, manganese, nickel, cobalt, and chromium, magnetite, hematite, various ferrites, manganese alloys, and other ferromagnetic alloys, which are made into fine powder with an average particle size of about 0.05 to 5 pm. can be used. The amount of magnetic fine particles contained in the magnetic toner is 15 to 70% by weight (more preferably 25 to 70% by weight) of the total weight of the magnetic toner.
45% by weight) is good.

Furthermore, the toner of the present invention may contain various release agents as necessary. For example, polyfluorinated ethylene, fluororesin, fluorinated carbon oil, silicone oil, low molecular weight polyethylene, low molecular weight polypropylene, etc. are preferably used in an amount of 0.1 to 10% by weight based on the toner.

The acid value of the polyester resin and toner according to the present invention is J
It is measured according to the method of ISKOO70. However, if the resin and toner do not dissolve in the solution, it is okay to use a good solvent such as dioxane (in the case of toner, measurements are taken without adding any external additives.

In the present invention, the outflow start temperature and softening point of the toner binder resin are measured using an elevated flow tester using an elevated flow tester (Shimadzu flow tester, C) shown in FIG.
FT-500 type) is used.

First, sample 3 with a weight of 1.0 g was molded using a pressure molder.
, with a heating rate of 5.0°C/min, a load of 10 kgf applied by plunger 1, diameter φ1 non, length 1
It was extruded from a nozzle 4 of 1.0 mm in diameter, and the amount of plunger descent of the flow tester was thereby measured.

At this time, when the height of the S-curve in the flow tester's plunger descent amount-temperature curve (see outflow curve Figure 2) is h, the temperature corresponding to h/2 is defined as the softening point, and the sample outflow starting point is The temperature at is the outflow start temperature.

[Example] Hereinafter, the present invention will be specifically explained with reference to resin production examples, examples, and comparative examples, but these are not intended to limit the present invention in any way. Note that all parts used are parts by weight.

Production 1. Raw materials were charged into a reactor equipped with a distillation column according to the composition shown below.

Furthermore, dibutyltin oxide was added at 0.0% relative to the total acid components.
After 4 hours, the system was depressurized to 5 mmHg when the distillation of water in the system stopped and the dialcohol component was distilled. The rotational load on the stirring blade gradually increased as the mixture was discharged, and after 1.5 hours, the load began to increase rapidly. When the pressure in the system was changed to 50 mmHg, the stirring load increased slowly. When this operation was repeated several times until the pressure in the system reached 300 mmHg, almost no distillate components were generated (and the stirring load was reduced to less than three times the starting level. At this point, the pressure in the system The pressure was returned to normal pressure and stirring was continued for about 1 hour.After the pressure was returned to normal pressure, there was hardly any increase in the stirring load, and the crosslinked polymer could be easily taken out from the reaction tower after the reaction was completed.

The acid value of this resin is 1.0 mgKOH/g, the Tg is 60°C, and the outflow start temperature by a flow tester is 9.
1°C, and the softening point was 133°C.

Using the same composition as Production Example 1, the polymerization reaction was started in the same manner as Production Example 1, and the pressure in the system was reduced to 5 mmHg, but after that the pressure in the system increased. When the distillate was continued to be removed without cooling, the reaction temperature reached 300℃ after 3 hours, even though the cooling capacity of the reaction tower was maximized.
℃, at which point the pressure was returned to normal and the reaction was stopped. At this time, the stirrer was also overloaded and stopped. Removal of the crosslinked polymer from the reaction tower was extremely difficult, and only about 40% of the charged amount could be taken out.

The acid value of this resin is 23.0 mgKOH/g, and the Tg
was 61'C, the outflow start temperature was 120C and the softening point was 160C by a flow tester.

Milk 1 plate Uni 1 Composition ratio of raw materials A, B, C, D, E in Production Example 1 (
The polymerization operation was carried out in the same manner as in Production Example 1, except that the rno (rno: 12%) was changed. (However, the elapsed time until the end of the reaction is different.) Here, the physical properties of the obtained resin are shown in Table 1 below (in addition,
The cases of Production Examples 1 and 2 are also shown. ).

(Margin below) Examples will be described below, and the evaluation methods for fixability and developability were as follows unless otherwise specified.

Evaluation of fixing performance> The fixing unit of a Canon Fe-5 copying machine (the pressure between the upper and lower rollers was 0.30 kg/cm in linear pressure, the nip width was 3.0 kg/cm).
0 mm) and set the temperature of the upper roller to 100~2
The linear velocity was set to be variable at 50°C, and the linear velocity was set to 60mm/
A separate fixing device fixed at sec was prepared. The upper roller is not coated with release oil, etc., and the set temperature is varied.
An unfixed image was passed through the paper at each temperature setting, and the fixing properties and offset properties were evaluated. Regarding the fixing performance, the fixing point was set at a temperature at which the image density decrease rate was 7% or less after vibrations were damped using Silbon paper with a load of 50 g/cm'' applied on the fixed image.

The offset property was determined based on the degree of dirt on the image margins and the fixing members such as the upper and lower rollers.

<Evaluation of Developability> Using a Canon NP5540 copying machine (using a black developer for magnetic toner and a color developer for non-magnetic toner), a continuous copying test of 10,000 sheets was conducted. In the case of non-magnetic toner, the toner to carrier ratio T/c ratio was set to 8/100. The carrier used was a ferrite core coated with a styrene-methyl methacrylate-fluorine copolymer. The NP5540 machine was also used to create unfixed images for the fixation test.

... 3 parts The mixture of the above formulation was melt-kneaded using a twin-screw extruder, cooled, and pulverized and classified to obtain a black fine powder with a weight average particle size of about 11 pm.

The acid value of this black fine powder is 0.5 mgKOH/g,
The amount of blow-off charge to the iron powder was +13.2 μc/g. Next, 0.4 parts of amino-modified silicone oil-treated silica fine powder was externally added to 100 parts of the black fine powder to obtain a positively charged magnetic toner. The blow-off charge amount of this toner against iron powder was +15.0 H/g.

Regarding fixing performance, the fixing point is 130'C, high temperature offset occurs from 190'C, and the fixing temperature is 6.
It was also 0°C, which was very good.

Regarding developability, the image density was maintained at 1.3 to 1.4, and images without fogging, scattering, or roughness were obtained unchanged from the initial stage.

The same toner as in Example 1 was used, and the fixing device was as shown in FIG. 3, consisting of a pressure member that was in pressure contact with the heating body and brought the recording material into close contact with the heating body through a film. It was carried out using an external fixing device. As the material of the fixing film 5, an endless film was used, which was based on a polyimide film and coated with 10 pm of a release layer in which a conductive material was added to a fluororesin. The pressure roller 18 is made of silicone rubber, has a nip width of 3.5 mm, and has a linear speed of 60 mm.
It was performed at mm/sec. The film is driven by the drive roller 16 and the driven roller 17, and by tension, moves in the direction of the arrow without wrinkles. Further, the heating element 11 is a linear heating element with a low heat capacity, and obtains pulsed energy to regulate the temperature.

As a result, the fixing point was 130° C., and the temperature at which high-temperature offset occurred was 200° C., indicating extremely excellent fixing properties. Further, there were no problems such as wrapping around the fixing member during paper ejection.

... A fine blue powder having a weight average particle size of about 12 μm was obtained using a mixture containing 3 parts or more of the formulation in the same manner as in Example 1.

The acid value of this blue fine powder is 3.2 mgKOH/g,
Blow-off charge amount for iron powder is +18.51Lc/g
Met. Next, 1.0 part of amino-modified silicone oil-treated silica fine powder was externally added to 100 parts of the blue fine powder to obtain a positively charged nonmagnetic pre-toner. The blow-off charge amount of this toner against iron powder is +16.3 μc/g
Met.

Regarding fixing performance, the fixing point is 140°C, high temperature offset occurs from 210°C, and the fixable temperature is 70°C.
There was, and it was very good.

Regarding developability, the image density is maintained at 1.3 to 1.4,
Clear blue images without fogging, scattering, or roughness.
This has remained unchanged since the beginning.

Furthermore, there was no carrier adhesion or spent carrier formation.

Same as Example 1 except that the resin of Production Example 3 was used instead of Production Example 1 used in Example 1, and 2 parts of dibutyltin borate was used instead of iron (n) acetyl acetate. The acid value of the black fine powder obtained was 1.5 mgKOH.
/g, and the blow-off charge amount for iron powder is +10.
The blow-off charge amount of the externally added toner was 71 Lc/g, and the blow-off charge amount of the externally added toner was 13.0 μc/g.

Regarding fixing properties, the fixing point was 135°C, and high temperature offset occurred at 210°C. Furthermore, the fixable temperature was 75° C., which was very excellent.

Regarding developability, the image density was maintained at 1.3 to 1.4, and images without fogging, scattering, or roughness were obtained unchanged from the initial stage.

<Comparative Examples 1 to 3. Comparative Example 2'> Next, the organometallic compound was removed from Examples 1 and 3.4,
The rest was the same as in each example, and the results are shown in Comparative Examples 1, 2.2', and 3 below.

Ratio 10 skin 1 The acid value of the toner before external addition is 6.1 mgKOH/g, the charge amount is +6.3 pc/g, the charge amount of the external addition toner + loμc/g
It became.

The fixability was not much different from Example 1 and there were no problems. However, regarding the developability, the initial image density was 1.2, which was a little inferior but still at a practical level, but after 1000 sheets, the image density was 1.0. At the same time, fog started to become noticeable, and
000 sheets was not enough for practical use, and the test was discontinued.

The acid value of the toner before external addition is 12.0 mgKOH/g, the charge amount is -21.5 μc/g, and the charge amount of the external addition toner is +4.
It became 2pc/g.

An attempt was made to mix the toner with a carrier to act as a starter, but the test was discontinued at this point as it was hardly mixed.

In Example 3, 4 parts of nigrosine dye was added except dibutyltin borate (same as in Comparative Example 2), and the other conditions were the same as in Example 3. The acid value of the toner before external addition was 11.8mgKOH/g, charge amount +4.2μc/g
, the amount of charge of the externally added toner was +15.3 pc/g.

Regarding fixing properties, although the high temperature offset occurrence temperature was 200° C., which was slightly inferior to that of Example 3, it was still at a practically acceptable level. However, regarding developability, although image density is achieved, toner scattering and
The fog was so bad (it was not very useful for practical use).

Comparison ■ The acid value of the toner before external addition is 5.7 mgKOH/g, the charge amount is ÷ 7.5 pc/g, the charge amount of the external addition toner + 10.0 lc
/g.

Regarding fixing properties, although the high temperature offset occurrence temperature was 200° C., which was slightly inferior to that of Example 4, it was still at a practically acceptable level. However, in terms of developability, the image density was 1.0 after 2000 sheets.
At the same time, the fog decreased below 0, and the test was stopped at 5,000 sheets.

Comparative Examples 4 to 6> Next, the resin used in Example 1 was compared to Production Examples 2 and 4, respectively. When the same procedure as in Example 1 was carried out except that E> was used, the results shown in Comparative Examples 4 to 6 below were obtained.

Engineering comparison 1 The acid value of the toner before external addition is 27.0 mgKOH/g, the charge amount is -12.0 pc/g, the charge amount of the external addition toner is -1,
It was 1 pc/g.

Developability was out of the question, so we only evaluated fixability by replacing the external additive with negative silica (unfixed images were made using Canon NP-
270RE machine).

The fixing point was 180° C., and it was not practical as a negative toner or as a low-temperature fixing toner.

Comparison■2 The acid value of the toner before external addition is 0.5 mgKOH/g, and the charge amount is +14.2 μc/g.The charge amount of the toner with external addition is ÷15.
The final value was 5c/g.

As for fixing properties, although the fixing point is as low as 110° C., offset occurs in any temperature range, and when we actually tested it on an NP5540 machine, the offset image wrapped around the fixing device, making it impossible to feed the paper.

L comparison ■ E The acid value of the toner before external addition is 7.6 mgKOH/g, the charge amount is +3.1 uc/g, the charge amount of the external addition toner is +9.2 μc/
It became g.

Regarding fixability, the fixing point was 190° C., making it impractical as a low-temperature fixing toner.

The developability was also at the same level as Comparative Example 3, and it was not practical as a positively charged toner.

Table 2 summarizes the results of Examples and Comparative Examples.

According to this, it can be clearly seen that the toner of the present invention has excellent heat fixability and image characteristics as a positively chargeable toner.

(The following is a blank space) [Effects of the Invention] As described above, according to the heat-fixable positively chargeable toner of the present invention, it is possible to satisfy all of offset resistance, blocking resistance, low-temperature fixability, etc. Yes, fog,
Clear images without scattering or roughness can be obtained.

[Brief explanation of drawings]

FIG. 1 is a schematic diagram showing an elevated flow tester used to measure the outflow start temperature and melt viscosity according to the present invention. FIG. 2 is a graph showing the relationship between plunger descent amount and temperature of the device shown in FIG. 1. FIG. 3 is a schematic diagram showing a fixing device used in an embodiment of the present invention. Figure 4 shows the DS for defining the glass transition temperature (Tg).
C shows an endothermic curve. 1...Piston (plunger) 2...Cylinder 3...Sample 4...Gui (nozzle) 5...Gui (nozzle) presser 11...Heating body 12...Alumina substrate 13.・Resistive material 14 ・Temperature detection element 15 ・Fixing film 16 ・Drive roller 17 ・Followed roller 18 ・Pressure roller 19 ・Recording material 20 ・Unfixed toner 21 ・・・Entrance guide

Claims (3)

[Claims] (1) A crosslinked polyester resin with an acid value of 0.1 to 10 mgKOH/g and 0.1 to 100 parts by weight of the resin.
1. A positively chargeable heat-fixable toner, comprising at least 10.0 parts by weight of an organometallic compound containing a divalent or higher valence metal. (2) Heat fixing properties according to claim 1, wherein the crosslinked polyester resin has an outflow start temperature in an elevated flow tester in a range of 85 to 105°C, and a softening point in a range of 120 to 150°C. Positively chargeable toner. (3) The positively chargeable heat-fixable toner according to claim 1, having an acid value of 5 mgKOH/g or less.