JPS6037470B2 - Positively chargeable toner - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a positively charged toner for electrostatic recording and electrophotography, and particularly to a toner that is subjected to a reversal phenomenon using a magnetic brush method.

The magnetic brush method is a type of dry development method for electrostatic latent images, in which toner is charged to a desired polarity by friction between magnetic carrier particles and toner particles in a rotating magnetic brush, and converted to electrostatic charge on a recording medium. This method involves suction and development.

The reversal development method is a method in which the charge portion induced in the non-travel portion of the electrostatic charge image due to the peripheral electric field effect is developed with toner of the opposite polarity to the charge (same polarity as the electrostatic charge image portion), and is particularly useful for developing line drawings. It is said to be advantageous.

However, if the electrostatic attractive force between a carrier particle and a toner particle is not sufficiently overcome by the centrifugal force of the rotating magnetic brush, the toner particles will scatter, causing fog or contaminating the developing device. In particular, as the speed of recording increases, the need for high-speed rotation of the magnetic brush increases, and the problem of toner scattering becomes serious. Furthermore, even if the electrostatic attractive force between the carrier particles and a single toner particle is large enough to prevent the toner particles from scattering, capri may occur if the toner particles are not uniformly charged.

In particular, when applying the reversal development method, if some particles of opposite polarity are mixed in the toner particles, these particles of opposite polarity will be attracted to the background area that has the same charge as the toner polarity, causing capri. arise. The problems of fogging and contamination due to toner scattering, and fogging due to uneven toner charging can be effectively overcome by using toner that is uniformly and sufficiently charged.

However, simply dispersing the nigrosine dye in a resin using an appropriate method does not provide sufficient chargeability, and It is difficult to solve the above problems due to insufficient dispersion. Such an example is
Polystyrene-rosin modified maleic acid alkyd resin shown in Reference Example 1 of Publication No. 5669, epoxy resin shown in the comparative example of the present invention, polystyrene-poly(
Examples include toners obtained from styrene-butyl acrylate mixtures or polyesters and nigrosine dyes. Therefore, a method was devised as disclosed in Japanese Patent Publication No. 48-25669, in which a low-molecular organic monomer or dicarboxylic acid is reacted with a nigrosine base, and the nigrosine salt is added to the resin.

However, with this method, good results can be obtained when combined with a polystyrene-rosin modified maleic acid alkyd resin mixture and polystyrene as shown in Examples 1 and 10 of Japanese Patent Publication No. 48-25669; In the case of resins, such as poly(styrene and/or methacrylic acid acrylic ester) resins, nigusine salt may be too compatible with the resin, causing a drop in the glass transition temperature of the toner, causing a decrease in the toner's glass transition temperature. There is a remarkable tendency to sacrifice the free flow properties of the toner, and a new problem arises in that the toner becomes unusable as a developer, or even if it is not unusable, the toner becomes agglomerated and the workability deteriorates. The cause of this is not clear, but poly(styrene and/or methacrylic acid ester-acrylic ester) resins contain acrylic ester and methacrylic acid ester moieties that have a molecular structure similar to the organic mono or dicarboxylic acid in nigrosine salt. It is assumed that the compatibility is very good because of the As described above, even if a toner is manufactured by combining nigrosine salt and a resin, good results may not always be obtained. The present inventors have discovered that in order to produce toners that exhibit good results using poly(styrene and/or methacrylic acid ester-acrylic ester) based resins,
By introducing a monomer having a carboxyl group into the resin molecule, we succeeded in directly dispersing the nigrosine dye into the resin using an appropriate means, and achieved good results, i.e., no fogging or contamination due to toner scattering. The present inventors have discovered that it is possible to produce a toner that does not have the problem of fogging due to non-uniform charging of the toner, and is free from the risk of a drop in glass transition temperature, and has accomplished the present invention.

That is, in the present invention, (R is hydrogen or a methyl group, R2 is hydrogen or an alkyl group having 1 to 4 carbon atoms.

) and/or (R3 is an alkyl group having 1 to 12 carbon atoms.

) (R4 is an alkyl group having 1 to 12 carbon atoms.

) and a copolymer obtained from (the c-component accounts for 1 to 2% by weight in the copolymer); The present invention relates to a positively chargeable toner containing the present invention.

The copolymer which is the cell component of the present invention (R, is hydrogen or CH8 group, R2 is hydrogen or has 1 to 1 carbon atoms)
4 is an alkyl group.

) and/or (R3 is an alkyl group having 1 to 12 carbon atoms.

) (R4 is an alkyl group having 1 to 12 carbon atoms.
) and are copolymerized, but the 'c' component must be 1 to 2% by weight of the total.

When the amount is less than 1% by weight, the dispersion effect of the nigrosine dye is reduced, and when it exceeds 2% by weight, the resin tends to become negatively chargeable, making it unsuitable as a positively chargeable toner resin.

Components 'a) and 'b) are blended so that the resin has an appropriate glass transition temperature and softening point as a toner resin. % by weight, the 'b' component is 10-4% by weight of the whole. Examples of the wind component 'a-' of the present invention include styrene/Q-methylstyrene, 0-methylstyrene, p-butylstyrene, methyl methacrylate, n-propyl methacrylate, isopropyl methacrylate, methacrylate. n-butyl lylate Isobutyl methacrylate, t-butyl methacrylate, n-bentyl methacrylate, isobentyl methacrylate, neobentyl methacrylate, 3-(methyl)butyl methacrylate, hexyl methacrylate, octyl methacrylate, nonyl methacrylate, methacrylate Examples include decyl acid, undecyl methacrylate, and dodecyl methacrylate.

In addition, examples of [b' in component -Pentyl, isobentyl acrylate, neobentyl acrylate, 3-(methyl)butyl acrylate, hexyl acrylate, heptyl acrylate, octyl acrylate, nonyl acrylate, decyl acrylate, undecyl acrylate, dodel acrylate, etc. can be given. When synthesizing the wind component of the present invention, a desired polymerization method such as solution polymerization or suspension polymerization is employed, and the catalyst has sufficient catalytic activity such as penzoyl peroxide or azobisisoputilonitrile. A catalyst with .

Furthermore, for the purpose of controlling the molecular weight of the copolymer, chain transfer agents such as triethylamine, carbon tetrachloride, carbon tetrabromide, n-butyl mercaptan, etc., which give desired results, can be omitted. The glass transition temperature and softening point of the copolymer which is the wind component of the present invention are mainly determined by the blending amounts of components (a) and 'b' in the wind component as described above, but in addition to this, It can be adjusted by the amount of catalyst and, if desired, by a suitable chain transfer agent as shown above, and the desirable range is a glass transition temperature of 45 to 90 qo and a softening point (ring and ball method) of 85 to 140 oo. The nigrosine dye, which is the 'B} component of the present invention, refers to an alcohol-soluble nigrosine dye and a nigrosine derivative that exhibits basicity, and is used to impart positive charging polarity to toner particles when carrier particles and toner particles are rubbed together. It is something that can be added to. Examples of such nigrosine dyes include nigrosin (Nigrosin).
eProduct name, Ikeda Chemical), Orient Spirit Black AB (OrientSpmtBlac)
kAB), Orient Spirit Black
Bee (OrientSpiritBlackSB) (both trade names manufactured by Orient Chemical), SpiritBlack (SpiritBlack) Snake. 850, Spirit Black M. 920, Spirit Black (SpmtBlack) M. Satoshi 0 (
Both are product names (manufactured by Sumitomo Chemical), nigrosine base,
NfgrosineBase N [trade name, National Aniline Divergence Ally Chemical. &Dye Corporation (NatioMI
Aniline Div Nagiliee Chemic
Al & DyeCorp] Nigrosine Base NB (Nigosinc axis seNB) [Product name, manufactured by Williams Ltd.]
, Nigrosine-based Geebee
BaseGB) [Product name: Farbenfab
rikenBayer AG. )], Nigrosine Base LK (Ni nail osIM BaseLK) [Product name, BAZUF (bag disheAniline & So F.
abrikA. Examples of dyes include Nigrosine Base SEEX (trade name, manufactured by Orient Chemical Co., Ltd.), but the dyes are not limited to the examples described herein.

The negative and B} components in the present invention are 'B'/■=1/
loo920/10 government is 2/100~10'1
It is blended in a weight ratio of 0.00.

When {B}/■ is 2/I00, it is difficult to impart good positive chargeability to the toner, and when 'B'/■ is 20/
Above 100, the resulting image has low density. The object of the present invention can be achieved by using the above-mentioned component be able to.

The toner according to the present invention is produced by melt-mixing wind and component [B}, and other color-adjusting dyes and pigments, such as carbon black, selected as necessary, at an appropriate degree of overflow in the range of 80 to 200 degrees. It is produced by cooling, pulverizing and classifying to the desired particle size.

The thus produced toner has the following properties: When the component (1) and the Tsukuda component are melt-mixed in the range of 80 to 200°C, when the 'B' component is alcohol-soluble nigrosine, it is uniformly dispersed in the component; When it is a basic nigrosine derivative, it is uniformly dispersed in the harmful component and partially reacts with the carboxyl group of the wind component. The toner according to the present invention has a glass transition temperature of 50 to 90 qo and a softening point (ring and ball method) of 90 to 140 qo, as long as the developing device and the fixing device that fixes the developed image to the support are used under normal conditions. It is desirable that the average particle diameter is 1 to 50 mm, preferably 5 to 30 mm, but this is not the case when used under special conditions.

The toner according to the invention forms a developer together with particulate carriers, such as powdered iron, magnetic oxides, glass beads, and the like.

Any particulate carrier may be used as long as it imparts the desired triboelectric properties to the toner particles, and is not limited to the above-mentioned examples of carrier particles. Hereinafter, the details of the present invention will be explained with reference to Examples.

Synthesis Example 1 A 4-necked flask equipped with a stirring bed, a nitrogen blowing tube, a thermometer, a reflux condenser, and a dropping funnel was charged with 1200 g of isopropanol as a solvent, and the temperature was raised to 75 qo while stirring and kept warm.

Next, a mixture of 1,060 ml of styrene, 700 ml of butyl acrylate, 240 ml of methacrylic acid, and 50 ml of azobisisobutyronitrile was added dropwise into the flask kept at 760° C. over 4 hours to effect polymerization. . Immediately after the dropwise addition was completed, the temperature was raised to 80 oo and kept at this temperature for an additional 4 hours to continue the reaction. Then, the contents were taken out and dried under reduced pressure by heating to obtain a solid copolymer. This copolymer has a glass transition temperature of 68qC and a softening point (ring and ball method) of 115oo.
The acid value was 72m9KOH/night. Synthesis Example 2 In the same synthesis apparatus as in Synthesis Example 1, isopropanol 12 was added as a solvent.
00 Yu was prepared and the temperature was raised to 75q0 while stirring.

Next, a mixture of 1060 g of styrene, 700 g of butyl acrylate, 240 g of methacrylic acid and 849 g of azobisisobutyronitrile was added dropwise into the flask kept at 75° C. over 4 hours to effect polymerization. Immediately after the dropwise addition was completed, the temperature was raised to 8,000 ℃, and the temperature was kept for an additional 4 hours to continue the reaction. The contents were then taken out and dried under reduced pressure by heating to obtain a solid copolymer. This copolymer has a glass transition temperature of 6.0 and a softening point (ring and ball method) of 10600.
The acid value was 70 units and 9 KOH/night. Synthesis Example 3 A synthesis apparatus similar to Synthesis Example 1 was charged with 1,200 ml of isopropanol as a solvent, and the temperature was raised to 7,500 ml while stirring and kept at that temperature.

Next, a mixture of 1,700 g of styrene and 100 g of azobisisobutyronitrile was added dropwise into the flask kept at 7,500 g over 4 hours to effect polymerization. Immediately after dropping, the temperature was raised to 80 oo, and then 4
The reaction was continued by keeping it warm for an hour. The contents were then taken out and dried under reduced pressure by heating to obtain solid polystyrene. The polystyrene had a glass transition temperature of 104 qC. Synthesis Example 4 Pour 1200 g of isopropanol as a solvent into the same synthesis apparatus as in Synthesis Example 1, and add 75 q of isopropanol while stirring.
The temperature was raised to 0.

Next, a mixture of 1050 g of styrene, 700 g of butyl acrylate and 50 g of azobisisobutyronitrile was added dropwise into the flask kept at 750 C over 4 hours to effect polymerization. Immediately after dropping, add 800
The temperature was raised to 0, and the reaction was continued by keeping the temperature for an additional 4 hours. The contents were taken out using a vacuum cleaner and dried under reduced pressure by heating to obtain a solid copolymer. This copolymer had a glass transition temperature of 3900. Synthesis Example 5 Neobentyl glycol 44 was placed in a 4-necked flask equipped with a stirring device, a thermometer, a nitrogen blowing tube, and a condensed water distillation tube.
2 parts, 161 parts of trimethylolfuropane and 5 parts of distilled water
I prepared it for 4 nights and raised the temperature to 8000℃ while stirring and kept it warm.

Next, 830 g of terephthalic acid was gradually added and stirred well.

Then, 80% of catalytic dibutyltin oxide was added, and 18% of the catalyst was added.
The temperature was raised to 0 to 190 qo to cause a reaction. When the amount of condensed water reached half of the theoretical amount, the temperature was further raised to 220 pm to continue the reaction. End point was determined by acid. The obtained polyester resin has an acid value of 6, 9KOH/unit, and a softening point (
ring and ball method) was 12,000. Example 1 The resin 900% obtained in Synthesis Example 1 was mixed with Orient Spirit Black SB (Orient SpmtBla).
ckSB) (manufactured by Orient Chemical Co., Ltd.) and carbon black #44 (manufactured by Mitsubishi Kasei Co., Ltd.) for 50 g.
Melt mixing was performed at 0 to 10,000.

After cooling, it was crushed and classified to obtain a toner. This toner has an average particle size of 10 to 20 French, a glass transition temperature of 760,
The softening point (ring and ball method) was 12,500. 5 parts by weight of the above-mentioned toner and a volume resistivity of 8 x lpiQ and enemy iron powder (100
~8% by weight of particles with a particle size of ~400 mesh) 10
parts by weight were mixed well to prepare a developer.

Next, reversal development was performed using an office copying machine equipped with a selenium drum rotating at a circumferential speed of about 10 per second as a photoreceptor. As a result, it was possible to obtain a good positive image without fogging from a negative original. Example 2 5 parts by weight of the toner obtained in Example 1 and a volume resistivity of 90×1 p0. 10 parts by weight of skin iron oxide powder (more than 8% by weight having a particle size of 100 to 400 mesh) were mixed well to prepare a developer.

Next, reversal development was carried out using an office copying machine equipped with a selenium drum rotating at a circumferential speed of about 10 per second as a photoreceptor. As a result, a fog-free image with particularly high line image density was obtained due to the edge effect. Example 3 5 parts by weight of the toner obtained in Example 1 and 10 parts by weight of iron oxide powder having a volume resistivity of 90 x 1 and ○ (more than 8% by weight of particles with a particle size of 100 to 400 mesh) were mixed together. The mixture was mixed to form a developer.

Next, a selenium drum rotating at a circumferential speed of about 40 arc/sec as a photoreceptor was uniformly charged with a corona voltage + shipside V, and then He-Cd
Information was written using a laser, and reversal development was performed using the developer described above. As a result, a good image with no Cap IJ and high image density was obtained. Further, toner scattering from the developing device did not occur at all. Example 4
The resin obtained in Synthesis Example 2, Nigrosine Base. NigrosineBaseEX (manufactured by Orient Chemical) 50 and carbon black #44
, 50 minutes, and then melt-mixed at 90 to 10 degrees using a Konida PR-46.

After cooling, it was crushed and classified to obtain a toner. This toner has an average particle size of 10~20r, a glass transition temperature of 65°C, and a softening point (
ring and ball method) was 115 qo. 5 parts by weight of the above-mentioned toner and iron oxide powder (100 to 4
0.00 mesh particle size (at least 8% by weight) and 10 parts by weight were mixed well to prepare a developer.

Next, reversal development was performed using an office copying machine equipped with a selenium drum rotating at a circumferential speed of about 10/sec as a photoreceptor. As a result, due to the edge effect, a fog-free image with particularly high line image density was obtained. Comparative Example 1 Epikoteloo 7 (epoxy resin, manufactured by Shell Chemical) 900 yen, Orient Spirit Black SB (manufactured by Orient Chemical) 50 yen, and carbon black #44
, 50 minutes, and then melt-mixed using a Konida PR-46 at a temperature of 90 to 10,000.

After cooling, it was crushed and classified to obtain a toner. This toner is
The average particle size was 10 to 20 French, and the glass transition temperature was 8,800. The above-mentioned toner has a volume resistance of 8 x lpi○ with 5 parts by weight.
A developer was prepared by thoroughly mixing 10 parts by weight of arc iron powder (at least 8% by weight of particles having a particle size of 100 to 400 mesh). Next, reversal development was performed using an office copying machine equipped with a selenium drum rotating at a circumferential speed of about 10 k/sec as a photoreceptor. As a result, a positive image could be obtained from the negative original, but there was a lot of fog and the image was unclear. Comparative Example 2 Polystyrene 576 obtained in Synthesis Example 3, copolymer 324 obtained in Synthesis Example 4, Orient Spirit BlackS
B) (Orient Chemical Co., Ltd.) 50 Yen and Carpon Plaque #44, 50 Yen were mixed well, then Conida PR-4
6 was used for melt mixing at 90 to 10,000.

After cooling, it was crushed and classified to obtain a toner. This toner had an average particle size of 10 to 20 flea, a glass transition temperature of 81° C., and a softening point (ring and ball method) of 11,300. 5 parts by weight of the above-mentioned toner and volume resistivity of 90 x l pi○ skin iron oxide powder (100
~80% by weight of grain fleas of ~400 mesh) 10
parts by weight were mixed well to prepare a developer. Next, reversal development was carried out using an office copying machine equipped with a selenium drum that rotates at a circumference of about 10 per second as a photoreceptor. As a result, an image with high line image density was obtained, but some fogging was observed. Comparative Example 3 Polyester resin 900% obtained in Synthesis Example 5, Orient Spirit Black
intBlackSB) (manufactured by Orient Chemical Co., Ltd.) 50 mm and carbon black #44, 50 mm were thoroughly mixed, and then melt-mixed at 90 to 100 mm using Conida PR-46.

After cooling, it was crushed and classified to obtain a toner. This toner had an average particle size of 10-20r and a softening point (ring and ball method) of 129qo. 5 parts by weight of the above-mentioned toner and 10 parts by weight of iron powder with a volume resistance of 8 x 1 PQ/arc (more than 8% by weight of particles with a particle size of 100 to 400 mesh) were mixed well to prepare a developer. .

Next, reversal development was carried out using an office copying machine equipped with a selenium drum rotating at a circumferential speed of about 10 k/sec as a photoreceptor. As a result, it was possible to obtain a positive image from the negative original, but the image had a lot of fog. Comparative Example 4 5 parts by weight of the toner obtained in Comparative Example 3 and a volume resistivity of 90×1
A developer was prepared by thoroughly mixing 10 parts by weight of iron oxide powder of 100 to 400 mesh (8% by weight or more by weight).

Next, a selenium drum rotating at a circumferential speed of about 40 skins/second as a photoreceptor was uniformly charged with a corona voltage + shipside V, and then the He-Cd
Information was written using a laser, and this was reversely developed using the developer described above. As a result, there was almost no fog, but some toner scattering from the developing device was observed. Comparative Example 5 NigrosineBaseEX (manufactured by Orient Chemical) 50% and dodecanedioic acid (manufactured by Toagosei, melting point 128.6)
oo) 39 minutes were well melted and mixed at 14,000.

After thoroughly mixing 50 g of this mixture, 900 g of the resin obtained in Synthesis Example 2, and carbon flakes #44 and 50 g, they were melt-mixed at a temperature of 90 to 10,000 using a Konida PR-46. After cooling, it was crushed and classified to obtain a toner. This toner has an average particle size of 10 to 20 French and a glass transition temperature of 570.
It was 0. The above-mentioned toner and the toner obtained in Example 4 were placed in test tubes with an inner diameter of 1 ratio, and left in a constant temperature air chamber of 40 oo for one week. The toner obtained in Example 4 remained smooth and free-flowing. However, the above-mentioned toner was partially lumped and its free-flowing properties were impaired.

The present invention involves introducing a carboxyl group that is soluble or reactive with a nigrosine dye into poly(styrene and/or methacrylate acrylate) resin molecules, and dispersing the nigrosine dye as it is in the resin. Fog and contamination due to toner scattering, which were previously considered problems (these are problems in high-speed reversal development,
was considered a particular problem.

) and fog caused by non-uniform charging. The present invention also solves a new problem of the disadvantage of the conventional technique of adding a nigrosine dye as a salt of a low-molecular organic mono- or dicarboxylic acid, that is, the deterioration of the free-flowing properties of toners due to a decrease in the glass transition temperature. It is something to do.

Claims (1)

[Scope of Claims] 1 (A) ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼ (R_1 is H or CH_3 group, R_2 is hydrogen or an alkyl group having 1 to 4 carbon atoms.) and/or ▲ Numerical formula, There are chemical formulas, tables, etc. ▼ (R_3 is an alkyl group with 1 to 12 carbon atoms.) ▲ There are numerical formulas, chemical formulas, tables, etc. ▼ (R_4 is an alkyl group with 1 to 12 carbon atoms.) and A copolymer obtained from ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼ and/or ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼ Component (c) accounts for 1 to 20% by weight in the copolymer copolymer, and (B)
A positively chargeable toner containing a mixture of nigrosine dyes and/or a reactant.