JPH04311967A - Toner for electrophotography - Google Patents

Abstract

PURPOSE:To provide toner having a sharp grain size distribution and a small grain size, generating a high quality image and ensuring high durability by constituting the toner of powder particles of specific thermoplastic resin and a coloring agent. CONSTITUTION:In electrostatic image development toner comprising a coloring agent in powder particles mainly composed of thermo-plastic resin, a ratio of a coloring agent inorganic value D1 to organic value D0 (alpha= D1/D0) is kept at 0.9 or less. Also, a ratio of a thermoplastic resin inorganic value R1 to organic value R0 (beta/alpha) is kept within 0.1 to 3.3. Furthermore, powder particles mainly composed of the thermoplastic resin is dyed, using a coloring agent having a ratio alpha of 0.9 or less in combination with resin having a ratio beta/alpha within 0.1 to 3.3. Thereafter, the particles are covered with an antistatic control agent. The organic value is measured in term of a carbon atom number representing a methylene group, and the value of one carbon atom is determined as 20. The inorganic value is measured in term of a hydroxyl group value taken at 100. The number of other constituent groups and transformation part is determined on the basis of the hydroxyl group value of 100.

Description

[Detailed description of the invention]

0001

FIELD OF INDUSTRIAL APPLICATION This invention relates to a new toner for developing electrostatic images in electrophotography, electrostatic recording, etc.

0002

[Prior Art] In recent years, in order to improve the image quality and durability of electrophotographic systems, toner particles with small particle size and sharp particle size distribution have been developed.
Sufficient coloring power and uniform charging control are required. Toner for electrostatic charge development is usually produced by melt-kneading a thermoplastic resin and a colorant, pulverizing the mixture, and then classifying the mixture. When trying to obtain toner manufactured in this way with a small particle size and a narrow particle size distribution, production capacity and yield will be significantly reduced, and costs will increase. Poor toner charging characteristics occur due to non-uniform dispersion of the charge control agent. In addition, the surface shape of the particles obtained by pulverization has many protrusions, making it easy to fuse them to the carrier or toner thinning member. Furthermore, an expensive charge control agent that originally functions on the surface of the toner is also contained inside the toner, resulting in a high cost.

[0003] Therefore, many proposals have been made regarding toners that provide high image quality and high durability and methods for producing the same. For example, a method of forming core particles containing a colored pigment and a charge control agent by a suspension polymerization method (Japanese Patent Publication No. 51-1989)
14895 and Japanese Patent Publication No. 47-51830), but this method is difficult to remove the dispersion stabilizer etc. that adheres to the surface and tends to cause charging deterioration, and furthermore, in internal polymerization, the particle size is small. Moreover, it is difficult to stably produce particles with a narrow and sharp particle size distribution.

[0004] There is also a method of forming core particles containing a pigment and a charge control agent by a spray granulation method (Japanese Patent Publication No. 5, 1983).
No. 7-494 and Japanese Patent Publication No. 56-13945) have also been proposed, but this method is extremely difficult to control the particle size;
It has drawbacks such as requiring classification treatment after granulation, and the inability to use polymeric resins that are effective in preventing hot offset.

On the other hand, as a method for obtaining toner with a uniform particle size, there is a seed polymerization method in which the particles are grown by polymerization after forming the particle size, and a method using a solvent in which the monomer is a good solvent but the polymer is a poor solvent. Dispersion polymerization methods are known, but although these polymerization methods can obtain small resin particles with a sharp particle size distribution, it is difficult to internally add carbona black or other colorants. There have been various proposals in the past.

For example, JP-A No. 61-18965 describes a method of forming a coating layer of a colorant or the like on the surface of dispersed polymer particles using a jet mill device, and JP-A No. 63-2075 and JP-A-63- No. 23166 and Japanese Unexamined Patent Publication No. 63-244057 propose a method of embedding pigments in thermoplastic resin by applying mechanical strain, but these methods do not provide sufficient coloring power and do not coat the surface. Due to the presence of the colorant, toner fixability is poor and offset occurs, among other problems.

[0007] Furthermore, JP-A-50-46333, JP-A-61-228458, JP-A-63-10667, and JP-A-1-103631 disclose a method of dyeing resin particles in a dye solvent. Although it has been proposed, products colored by this method are dyed even inside the resin, and are less susceptible to the above-mentioned effects on the resin particle surface, and have good fixation and offset, but are insufficient in terms of coloring power. there were.

[0008]

[Problems to be Solved by the Invention] The present invention provides an electrophotographic toner that has improved the above-mentioned drawbacks.The purpose of the present invention is to provide a toner for electrophotography that has a sharp particle size distribution, small particle size, high image quality, and high durability. Another object of the present invention is to provide a toner with excellent dyeing properties, high coloring power, and excellent reliability.

[0009]

[Means for Solving the Problems] According to the present invention, in a toner for an electrostatic image developer comprising powder particles containing a thermoplastic resin as a main component and a coloring agent, the inorganic value (D
1) and the organic value (D0) (α=D1/D0) is 0
．． 9 or less, and the inorganic value (R1) of the thermoplastic resin is
and the ratio of the organic value (R0) (β=R1/R0) (
Provided is an electrostatographic toner characterized in that β/α) is in the range of 0.1 to 3.3, and furthermore, powder particles containing a thermoplastic resin as a main component have an α of 0.9 or less. Provided is a method for producing an electrophotographic toner comprising the steps of dyeing the toner using a colorant in combination with a resin having β/α in the range of 0.1 to 3.3, and then coating the toner with a charge control agent. Ru.

[0010] The inorganic value and organic value in the present invention are "
Systematic Organic Qualitative Analysis (Pure Materials Edition)” Fujita, p61-81
, (1953), and the organicity value is measured by the number of carbon atoms representing the methylene group, and the organicity value is measured by the number of carbon atoms representing the methylene group,
The value of the hydroxyl group is set as 20, and the inorganic value is set as 100 for the hydroxyl group, and based on this value, the values of other substituents and modified moieties are determined.

Table 1 shows the inorganic value (D1) and organic value (D0) of specific colorants.

[Table 1]

In the method of producing an electrophotographic toner by dyeing a coloring agent to a thermoplastic resin, in order to impart sufficient coloring power to the toner, the colorant has the above-mentioned inorganic value (D1). Ratio of organic value (D0) (α=D1/D0)
must be 0.9 or less. Most commercially available dyes have α=0.9 or more, and if a thermoplastic resin used in a toner is dyed with a dye having α=0.9 or more, sufficient coloring power cannot be obtained as a toner.

Examples of colorants preferably used in the present invention are as follows. Solvent Yellow-2, Solvent Yellow-3, Solvent Yellow-7, Solvent Yellow-11, Solvent Yellow-14, Solvent Yellow-16, Solvent Yellow-29, Solvent Yellow-56, Solvent Yellow-77, Solvent Yellow-104, Solvent Yellow-105, Solvent Yellow-112, Solvent Yellow-116, Solvent Yellow-150, Solvent Yellow-157, Solvent Yellow-160, Solvent Orange-1, Solvent Orange-2, Solvent Orange-7, Solvent Orange-60, Solvent Orange-68, Solvent Orange-72, Solvent Red-1, Solvent Red-2, Solvent Red-18, Solvent Red-19, Solvent Red-23, Solvent Red-24, Solvent Red-25, Solvent Red-
26, Solvent Red-27, Solvent Red-5
2, Solvent Red-143, Solvent Red-1
46, Solvent Red-147, Solvent Red-
149, Solvent Red-150, Solvent Red-151, Solvent Red-152, Solvent Red-155, Solvent Red-176, Solvent Red-177, Solvent Red-178, Solvent Red-179, Solvent Violet-13, Solvent Violet- 33, Solvent Blue-11,
Solvent Blue-12, Solvent Blue-14, Solvent Blue-35, Solvent Blue-36, Solvent Blue-63, Solvent Blue-78, Solvent Blue-82, Solvent Blue-87, Solvent Blue-90, Solvent Blue-91, Solvent Blue-92, Solvent Blue-93, Solvent Blue-94, Solvent Blue-95, Solvent Blue-97, Solvent Blue-98, Solvent Blue-99, Solvent Blue-103, Solvent Blue-105, Solvent Blue-108, Solvent Blue-109, Solvent Blue-111, Solvent Blue-112, Solvent Blue-116, Solvent Blue-134, Solvent Green-4, Solvent Green-5, Solvent Green-20, Solvent Green-23, Solvent Green-26, Solvent Green-28, Solvent Brown-1, Solvent Brown-3, Solvent Brown-4, Solvent Brown-5, Solvent Black-3, etc.

Furthermore, the composition of the thermoplastic resin used in the toner is determined by its thermal properties, charging properties, chloride resistance, matt properties, etc., and therefore the resin composition of the toner varies depending on the copying process. Therefore, in order to dye these resins, a proper combination of resin and dye is important. In this combination, the ratio of the inorganic value (R1) to the organic value (R0) of the thermoplastic resin (β=R1/R0) and the ratio of α (β/α) described above are 0.1 to 3.3. It has been found that sufficient coloring power can be imparted as a toner within this range.

The thermoplastic resin used in the present invention can be obtained in the form of pulverized particles or suspension polymerized particles, but in order to obtain a toner with a sharp particle size distribution and small particle size, it is possible to obtain the thermoplastic resin using a seed polymerization method or a dispersion polymerization method. It is preferable to use polymerized particles obtained by A wide variety of conventionally known monomers can be used as monomers for forming such polymerized particles.

For example, styrene, parachlorostyrene,
Vinyl toluene, vinyl chloride, vinyl bromide, vinyl fluoride, vinyl acetate, vinyl propionate, methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, n-butyl (meth)acrylate , isobutyl (meth)acrylate, dodecyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, lauryl (meth)acrylate, 2-hydrochitoethyl (meth)acrylate, hydroxypropyl (meth)acrylate, (Meth)acrylic acid 2-chloroethyl, (meth)acrylonitrile, (meth)acrylamide, (meth)acrylic acid, vinyl methyl ether, vinyl ethyl ether, vinyl isobutyl ether, vinyl methyl ketone, N-vinylpyrrolidone, N-vinylpyridine , ethylene, propylene, and butadiene.

[0017] An example of a method of dyeing the resin particles obtained by the above method with a colorant is a method of stirring and mixing the resin particles with the resin particles in a solvent that dissolves the colorant. The solvent used here can be a general-purpose organic solvent, but alcoholic solvents such as methanol, ethanol, n-propyl alcohol, iso-propyl alcohol, n-butyl alcohol, iso-butyl alcohol, and tert-butyl alcohol are preferred. . Further, the ratio of the resin particles to the colorant used varies depending on the monomer composition of the resin particles, the particle size, and the structure of the colorant, but it is preferably about 1 to 20% wt of the colorant to the resin particles.

A coating layer containing a charge control agent or a releasing substance may be provided on the surface of the particles dyed in this manner. As a charge control agent, nigrosine, an azine dye containing an alkyne group having 2 to 16 carbon atoms (described in Japanese Patent Publication No. 1627/1983)
, basic dyes (e.g. C.I.Basic Yel
low 2 (C.I.41000) C. I. Ba
sic Yellow 3,C. I. Basic
Red 1 (C.I.45160), C.I. I. Ba
sic Red 9 (C.I.42500), C.I.
I. BasicViolet 1 (C.I.4253
5), C. I. BasicViolet3 (C.I.4
2555), C. I. Basic Violet
10 (C.I.45170), C.I. I. Basic
Violet 14 (C.I.42510), C.I. I
．． Basic Blue 1 (C.I.42025
), C. I. Basic Blue 3 (C.I.
51005), C. I. Basic Blue 5
(C.I.42140), C.I. I. Basic BL
ue 7 (C.I.42595), C. I. Basi
c Blue 9 (C.I.52015), C. I
．． Basic Blue 24 (C.I.5203
0), C. I. Basic Blue 25 (C.
I. 52025), C. I. BasicBlue26(
C. I. 44045), C. I. Basic Gre
en 1 (C.I.42040), C. I. Basi
c Green 4 (C.I.42000), etc.
Lake pigments of these basic dyes (lake-forming agents include phosphotungstic acid, phosphomolybdic acid, phosphotungstic acid, tannic acid, lauric acid, gallic acid, ferricyanide, ferrocyanide, etc.), C.I. I. Solve
ntBlack 3 (C.I.26150), Hansa Yellow G (C.I.11680), C.I. I. Mord
lant Black 11, C. I. Pigme
ntBlack 1, benzoylmethyl-hexadecyl ammonium chloride, decyl-trimethylaluminum chloride, or dialkyltin borate compounds such as dibutyl or dioctyl, guanidine derivatives,
Polyamine resins such as vinyl polymers containing amino groups and condensation polymers containing amino groups;
No. 20153, No. 43-27596, No. 44-639
No. 7, metal complex salts of monoazo dyes described in No. 45-26478, Japanese Patent Publication No. 57-42752, Japanese Patent Publication No. 54
-415080, Special Publication No. 58-7384, Special Publication No. 58
Zn, Al of salicylic acid, dialkyl salicylic acid, naphthoic acid, dicarboxylic acid described in No. 9-7385
, Co, Cr, Fe and other metal complexes, and sulfonated copper phthalocyanine pigments.

Examples of mold release substances include low molecular weight polyolefins such as low molecular weight polyethylene, low molecular weight polyprolene, and oxidized polyethylene, natural waxes such as beeswax, carnauba wax, and montan wax, stearic acid, palmitic acid, myristic acid, etc. These include higher fatty acids, metal salts of higher fatty acids, and higher fatty acid amides. Although these can be used alone or as a mixture of two or more, it is preferable to use low molecular weight polyolefins, such as polypropylene.

[0020] As a method for coating the above-mentioned charge control agent and releasing substance, generally known methods can be employed. For example, by mixing dyed particles with a charge control agent or a release agent,
By applying mechanical energy to this mixture, the resin-coated coloring agent may be applied to the surfaces of the powder particles to coat them. Here, the mechanical energy can be applied by applying a grinding force, by applying an impact force to the mixture using high-speed rotating blades, or by causing particles to collide with each other or against a collision plate in a high-speed airflow. The specific driving device is Mechano Fusion (Hosokawa Micron Co., Ltd.), 1
Turbo mill (Japan Pneumatic Industry Co., Ltd.) is a type mill (Japan Pneumatic Industry Co., Ltd.) that uses a lower air pressure for grinding than normal grinding.
Turbo Kogyo Co., Ltd.), Hybridizer (Nara Kikai Seisakusho Co., Ltd.), Cosmomizer (Nara Kikai Seisakusho Co., Ltd.)
, automatic mortar, etc.

[0021]

[Example] First, an example of manufacturing a typical resin used in the present invention will be shown. Note that all parts are based on weight.

Production Example 1 15 parts of polyacrylic acid was dissolved in 150 parts of methanol, and the inside of the reaction vessel was replaced with nitrogen using nitrogen gas, and then a solution of 0.82 parts of azobisisobutylnitrile dissolved in 52 parts of styrene was added. , Stir at 60°C for 8 hours to polymerize, leave at room temperature overnight, decant to remove supernatant, add 100 parts of methanol, stir for 30 minutes, filter and dry to obtain 49 parts of white powder. Obtained. This powder has a volume average particle diameter (Dv) of 7.36μ
m, the ratio Dv/Dp to the number average particle diameter (Dp) is 1.09
Met.

Production Examples 2 to 9 Polymerization was carried out in the same manner as Production Example 1 except that the following monomers were used in place of the styrene used in Production Example 1, and the results shown in Table 2 below were obtained.

[0024]

[Table 2] St: styrene, n-BMA: n-butyl acrylate,
2EHMA; 2-ethylhexyl methacrylate, nB
A: n-butyl acrylate, MA: methyl acrylate, AA: acrylic acid, 4VPy: 4-vinylpyridine Next, the present invention will be explained by examples.

Example 11 - Resin particles obtained in Production Example 2 by heating and dissolving 0.5 parts of (4'-butylbenzene azo) 2-naphthol (α=0.51) in 100 parts of methanol (
10 parts of β=0.22, β/α=0.43) were added and stirred for 1 hour under heating and reflux to carry out dyeing. The mixture was then cooled to room temperature and filtered under suction to obtain a yellow powder. The amount of dyeing was 72.6 mg per 1 g of resin. This colored particle 10
part and 3,5-ditertiarybutylsalicylic acid zinc salt 0
．． After stirring 1 part with an Ooster blender for 5 minutes,
A yellow toner was obtained by processing with Hybridization NHS-0 (manufactured by Nara Kikai Seisakusho) at a rotation speed of 10,000 rpm for 5 minutes. A developer was prepared by mixing 3 parts of this toner with 100 parts of iron powder carrier. This developer was placed in a magnetic brush developing device to develop an electrostatic latent image formed on a selenium photoreceptor using normal electrophotography, and when this was transferred to plain paper while applying a corona discharge and heat-fixed, the resolution was An excellent yellow copy image was obtained.

Comparative Example 1 In place of 1-(4'-butylbenzene azo)2-naphthol in Example 1, 1-(4'-carboxybenzene azo)2-naphthol (α=1.04)0
．． Dyeing was carried out in the same manner as in Example 1 except that 5 parts were used, and the color of the powder was pale yellow, and the amount of dyeing was 2.5 parts per 1 g of resin.
5 mg, and the degree of coloring was insufficient.

Example 2C. I. Solvent Blue 11 (
α=0.85) was heated and dissolved in 100 parts of methanol, and the insoluble portion was filtered off. Resin particles 10 obtained in Production Example 6
The mixture was dyed at 50° C. for 1 hour, and then cooled to room temperature to obtain a blue colored powder. The amount of dyeing was 28.1 mg per 1 g of resin. A developer was prepared from this powder in the same manner as in Example 1, and an image was formed using the same copying machine as in Example 1, resulting in a clear blue copy image.

Example 3 Example 1 using the dyes and resins shown in the table below.
When dyeing was carried out under the following conditions, the following results were obtained.

[0029]

[Table 3] From the table, it can be seen that toners with α of 0.9 or more and β/α of 0.1 to 3.3 have good dyeing properties.

[0030]

Effects of the Invention Since the toner of the present invention has the above-mentioned structure, it has a sharp particle size distribution, small particle size, and has good dyeability and
Because it has excellent coloring power and durability, it provides images with high quality and excellent reliability.

Claims (2)

[Claims] 1. A toner for an electrostatic image developer comprising powder particles mainly composed of a thermoplastic resin and a colorant, in which the inorganic value (D1) and the organic value (D0) of the colorant are The ratio (α=D1/D0) is 0.9 or less, and the ratio (β
=R1/R0) (β/α) is in the range of 0.1 to 3.3. Claim 2: Powder particles containing thermoplastic resin as a main component, using a coloring agent with α of 0.9 or less, and β/α of 0.1.
A method for producing an electrophotographic toner, which comprises a step of dyeing in combination with a resin in the range of .about.3.3 and a step of coating with a charge control agent.