JP3216239B2 - Toner for developing electrostatic images - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a toner for developing an electrostatic image used in electrophotography, electrostatic recording, and electrostatic printing.

[0002]

2. Description of the Related Art Conventionally, a toner used in an electrophotographic method uses a pigment as a colorant and a finely divided colored powder in which a charge controlling agent for controlling electric charge is dispersed in a resin as a binder. Have been. These toners develop the electrostatic latent image on the photoreceptor by various developing methods including a magnetic brush developing method that is widely used at present, and are transferred from the photoreceptor to recording paper, and are called "fixing". An operation is performed to form a permanent image. As the fixing method, a heat roll fixing method, an oven fixing method, a flash fixing method and a pressure fixing method have been widely known. Among these fixing methods, a heat fixing method using a heat roll is generally often used from the viewpoints of fixing performance, safety, and machine cost. However, even with a heat roll fixing method having excellent fixing performance, the toner layer is not always sufficient because the toner layer is cracked or peeled off by external force such as bending or rubbing of paper. In order to solve this problem, a method of increasing the fixing temperature or decreasing the melt viscosity of the toner has been considered. That is, by fixing at a high temperature, the resin is sufficiently melted to adhere to the paper, and by using a resin having a low melt viscosity, sufficient fixing can be obtained even at a relatively low temperature, and the softness of the resin is added to the fixed paper. This is because it is effective for bending and rubbing. However, when the fixing temperature is increased, there is an upper limit of the material of the roll, and the power consumption further increases, causing a practical problem. In addition, when the melt viscosity of the resin is reduced, the strength of the resin is weakened, and the fixed image is easily cracked or partially peeled by bending or rubbing by external force on paper, which poses a practical problem.

[0003]

SUMMARY OF THE INVENTION An object of the present invention is to provide a toner which has solved the above-mentioned problems, and to provide a toner which can sufficiently fix a recording medium even at a lower temperature.

[0004]

Means for Solving the Problems The present inventors have made intensive studies to solve the above-mentioned problems, and as a result, have reached the present invention.

That is, the present invention is characterized in that the toner for developing an electrostatic image is at least ethylene and n-butylene.
Having a weight average molecular weight of 960 to 5720.
A general formula having a pour point of −50 ° C. to −15 ° C.
A binder containing the co-oligomer represented by (I),
-Styrene / acrylic graft polyester as resin
The object has been achieved by containing a resin or a polyester resin .

The present invention will be described in detail below.

Ethylene and n-butylene used in the present invention
The structure of the co-oligomer is as shown in the general formula (I).

Formula (I)

Embedded image R: C ₂ H ₅ x, y : integer x> y

The hydrocarbon compound having the above structure can be prepared by a medium / low pressure method using a coordination anion polymerization method using a Ziegler catalyst,
It can be obtained by a high-pressure method by a radical polymerization method, or thermal decomposition or oxidative decomposition of low-density polyethylene.

A co-oligomer of ethylene and n-butylene was prepared in the following manner. Nitrogen gas is replaced in a three-neck separable flask equipped with a stirring blade, a gas inlet tube, and an exhaust port equipped with a drying tube. Furthermore, after adding cyclohexane in a flask, a lithium tetradecyl aluminum solution is added. The mixture was externally cooled in an ice-water bath, and a titanium tetrachloride cyclohexane solution was added to prepare a catalyst. Ethylene and n-butylene were blown from the gas introduction tube while vigorously stirring the prepared catalyst suspension to polymerize the cooligomer. The co-oligomer thus prepared was adjusted by the ratio of lithium tetradecylaluminum and titanium tetrachloride cyclohexane and the reaction temperature to obtain co-oligomers I to V. The ratio of ethylene to n-butylene is 2: 1 to 10:
1 was synthesized. The catalyst may be other than those described above, and may be any ZiEgler catalyst of R ₃ Al—TiCl ₄ . The properties of the synthesized cooligomers are shown in Table 1.

[0011]

[Table 1]

The toner of the present invention has a melt viscosity measured by a flow tester of 1 × 10 ⁴ (100 ° C.) to 5 × 10 ⁵ po.
island (120 ° C.), desirably 1 × 10 ⁴ (1
00 ° C.) to 1 × 10 ⁵ poise (120 ° C.)
Glass transition point is 50 ° C to 75 ° C, preferably 55 ° C to
It shows a range of 70 ° C.

The binder resins used in these toners include polystyrene, styrene-acrylic acid copolymer, styrene-methacrylic acid copolymer, styrene-acrylic ester copolymer, and styrene-methacrylic ester copolymer. , Styrene resins such as styrene-butadiene copolymer, saturated polyester resin, unsaturated polyester resin,
Epoxy resins, phenolic resins, maleic acid resins, coumarone resins, polyalkyl resins, polyalkylene resins, polyalkyl acrylate resins, polyalkyl methacrylate resins, and graft polymerization resins of these resins. Needless to say, two or more of these binder resins may be used as appropriate.

Examples of the charge control agent for controlling charge include a nigrosine-based dye, a metal salt of a fatty acid, a quaternary ammonium salt, a metal-containing dye of an azo type, and a metal salt of salicylic acid. Can be selected and used.

The coloring agent used in the present invention includes:
Black colorants such as carbon black, aniline black and magnetite, and insoluble disazo, azo lake, condensed azo, phthalocyanine, quinacridone, isoindoline, dioxazine, perylene, perinone, thioindigo, anthraquinone, pyrocholine, fluorbin as organic pigments for color toners Quinophthalone is suitable.

[0016]

Embodiments of the present invention will be described below.

Example 1 Resin Styrene / acrylic graft polyester (MW = 12000 MW / MN = 2.5 Tg 61 ° C.) 90 parts by weight Cooligomer I 2 parts by weight Charge control agent Bontron S-34 2 parts by weight (Orient Chemical Industry Co., Ltd.) Coloring agent Carbon black # 40 6 parts by weight (Mitsubishi Chemical Corporation)

After mixing the above ingredients in a mixer, the mixture is melt-kneaded at 120 ° C. using a twin-screw extruder, cooled, pulverized by a jet mill, and classified by a gas stream classifier to obtain an average particle diameter of 1: 1.
Fine particles of 0 μm were obtained. Further, 0.2% of hydrophobized silica (R972 manufactured by Nippon Aerosil Co., Ltd.) was added to the fine particles, and the mixture was mixed for 1 minute with a mixer to prepare toner-1. The melt viscosity of this toner was measured using a flow tester (manufactured by Shimadzu Corporation).
× 10 ⁴ poise was shown.

Example 2 Resin Styrene / acryl graft polyester (MW = 12000 MW / MN = 2.5 Tg61 ° C.) 90 parts by weight Cooligomer II 2 parts by weight Charge control agent Bontron S-34 2 parts by weight (Orient Chemical Industry Co., Ltd.) Colorant Carbon Black # 406 6 parts by weight (manufactured by Mitsubishi Kasei Co., Ltd.) Toner-2 was prepared in the same manner as in Example 1 using the above-mentioned components.

Example 3 Resin Styrene / acryl graft polyester (MW = 12000 MW / MN = 2.5 Tg61 ° C.) 90 parts by weight Cooligomer III 2 parts by weight Charge control agent Bontron S-34 2 parts by weight (Orient Chemical Co., Ltd.) Colorant Carbon black # 406 6 parts by weight (manufactured by Mitsubishi Kasei Co., Ltd.) Toner-3 was prepared using the above-mentioned ingredients in the same manner as in Example 1.

Example 4 Resin Styrene / acrylic graft polyester (MW = 12000 MW / MN = 2.5 Tg61 ° C.) 90 parts by weight Cooligomer IV 2 parts by weight Charge control agent Bontron S-34 2 parts by weight (Orient Chemical Industry Co., Ltd.) Colorant carbon black # 406 6 parts by weight (manufactured by Mitsubishi Kasei Corporation) Toner-4 was prepared using the above-mentioned components in the same manner as in Example 1.

Example 5 Resin Polyester resin (manufactured by Arakawa Chemical) Lunaper 1416 (MW = 9881 MW / MN = 2.5 Tg 55 ° C.) 90 parts by weight Cooligomer II 2 parts by weight Charge control agent Bontron S-34 2 parts by weight (Orient Chemical Co., Ltd.) Colorant Carbon black # 40 6 parts by weight (Mitsubishi Chemical Corporation)

After mixing the above ingredients with a mixer, the mixture is melt-kneaded at 115 ° C. using a twin-screw extruder, cooled, pulverized by a jet mill, and classified by a gas stream classifier to obtain an average particle size of 1: 1.
Fine particles of 0 μm were obtained. Further, 0.2% of silica (R972 manufactured by Nippon Aerosil Co., Ltd.) subjected to a hydrophobic treatment was added to the fine particles, and the mixture was mixed for 1 minute with a mixer to prepare a toner-5. The melt viscosity of this toner was measured using a flow tester (manufactured by Shimadzu Corporation).
× 10 ⁴ poise was shown.

Comparative Example 1 Resin Styrene / butyl acrylate (MW = 12000 MW / MN = 3.2 Tg 62 ° C.) 90 parts by weight Cooligomer II 2 parts by weight Charge control agent Bontron S-34 2 parts by weight (Orient Chemical Industry Co., Ltd.) Coloring agent Carbon black # 40 6 parts by weight (Mitsubishi Chemical Co., Ltd.)

After mixing the above ingredients with a mixer, the mixture is melt-kneaded at 130 ° C. using a twin-screw extruder, cooled, pulverized by a jet mill, and classified by a gas stream classifier to obtain an average particle diameter of 1: 1.
Fine particles of 0 μm were obtained. Further, 0.2% of hydrophobized silica (R972 manufactured by Nippon Aerosil Co., Ltd.) was added to the fine particles, and the mixture was mixed for 1 minute with a mixer to prepare toner-6. The melt viscosity of this toner was measured using a flow tester (manufactured by Shimadzu Corporation).
× 10 ⁵ poise was shown.

Comparative Example 2 Resin Styrene / butyl acrylate (MW = 12000 MW / MN = 3.2 Tg 62 ° C.) 90 parts by weight Cooligomer V 2 parts by weight Charge control agent Bontron S-34 2 parts by weight (Orient Chemical Industry Co., Ltd.) Colorant Carbon Black # 406 6 parts by weight (manufactured by Mitsubishi Kasei Co., Ltd.) Toner 7 was prepared using the above-mentioned formulation components in the same manner as in Comparative Example 1 .

Comparative Example 3 Resin 90 parts by weight of styrene / acrylic graft polyester (MW = 12000 MW / MN = 2.5 Tg 61 ° C.) used in Example 1 Charge controlling agent Bontron S-34 2 parts by weight (Orient Chemical Industry Co., Ltd.) Colorant Carbon black # 406 6 parts by weight (manufactured by Mitsubishi Kasei Co., Ltd.) Toner-8 was prepared in the same manner as in Example 1 using the above prescription components.

Comparative Example 4 Resin Polyester resin used in Example 5 (manufactured by Arakawa Chemical) Lunaper 1416 (MW = 9881 MW / MN = 2.5 Tg 55 ° C.) 92 parts by weight Charge control agent Bontron S-32 (Orient Chemical 6 parts by weight Coloring agent carbon black # 40 (manufactured by Mitsubishi Kasei Corporation) 6 parts by weight A toner 9 was prepared using the above-mentioned ingredients in the same manner as in Example 1.

Comparative Example 5 Resin Styrene / butyl acrylate (MW = 12000 MW / MN = 3.2 Tg 62 ° C.) 92 parts by weight Charge control agent Bontron S-32 (manufactured by Orient Chemical Industry Co., Ltd.) 2 parts by weight Colorant carbon Black # 40 (manufactured by Mitsubishi Chemical Corporation) 6 parts by weight Toner 10 was prepared by using the above ingredients in the same manner as in Example 1.
It was created.

[0030] Using the toners 1 to 10 of Examples 1 5 and Comparative Example 1 to 5 Create a developer was prepared an unfixed image in a commercial copier. After that, the unfixed image on the transfer paper was passed through a heat roll fixing device (temperature: 170 ° C., pressure: 0.5 kg / cm) to obtain a fixed image. The fixing device used here uses a silicone rubber roll and is further coated with silicone oil. The fixability of the fixed image was measured using a rubbing tester.

Table 2 shows the results.

[0032]

[Table 2]

In this specification, various tests were performed as follows. Fixing property 1: Bending test Fixing property 2: Rubbing test ID: Image density is measured with Macbeth reflection densitometer RD-918 (Sakata Shokai) BG: Dirt on the image background is measured with Macbeth reflection densitometer RD-9
Measured at No. 18 (Sakata Shokai) Folding test method The fixed image is bent and set on a rubbing tester (manufactured by Taihei Rika Kogyo Co., Ltd.) and the crease is rubbed 10 times.

The load was set so as to be 1000 g / cm ² . Rubbing test method The fold of the image sample used in the bending test is extended, the felt is set, and rubbing is performed 10 times.

The load was set so as to be 10 g / cm ² . Melt viscosity measurement method Measured with a Shimadzu flow tester.

(Heating rate: 6 ° C./min, die: 1 mm × 1)
mmφ, load: 10 kg) Weight average molecular weight (Mw) Measured by gel permeation chromatography manufactured by Shimadzu Corporation. Molecular weight distribution (Mw / Mn) Measured by gel permeation chromatography manufactured by Shimadzu Corporation. Kinematic viscosity (cSt) According to JIS K2283. Pour point (° C.) According to JIS K2269.

[0037]

The copolymer of ethylene and n-butylene
Has a weight average molecular weight of 960 to 5720,
Contains cooligomers having a working point of -50 ° C to -15 ° C
And styrene-acryl graft as binder resin
After fixing with a heat roll, the polyester resin or the toner containing the polyester resin does not or hardly cause cracking or peeling when the obtained image is bent, so that the fixing performance can be improved.

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-54-119928 (JP, A) JP-A-56-110947 (JP, A) JP-A-1-22563 (JP, A) JP-A-3-3 203747 (JP, A) JP-A-4-9067 (JP, A) JP-A-60-252366 (JP, A) JP-A-1-29763 (JP, A) JP-A-59-188657 (JP, A) JP-A-3-168648 (JP, A) JP-A-2-275962 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) G03G 9/08

Claims (3)

(57) [Claims] 1. A is a copolymer of ethylene and n- butylene, represented by weight average molecular weight of Ri der 960-5720, liquidity point of -50 ℃ ~-15 ℃ formula (I) Contains cooligomers and is used as a binder resin.
Len / acrylic graft polyester resin or polyester
A toner for developing an electrostatic image, comprising a tellurium resin. General formula (I) R: C ₂ H ₅ x, y : integer x> y 2. A copolymer of ethylene and n-butylene.
Has a weight average molecular weight of 1545 to 2470.
The toner for developing an electrostatic image according to claim 1. 3. A copolymer of ethylene and n-butylene.
Has a pour point of -40C to -30C.
The toner for developing an electrostatic image according to claim 2.