JP2000284525A - Encapsulated toner for thermal pressure fixation - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain an encapsulated toner for thermal pressure fixation excellent in the dispersibility of a wax, having good low temperature fixability, releasability and anti-offsetting properties and excellent also in blocking resistance. SOLUTION: The encapsulated toner comprises a heat meltable core material containing a thermoplastic resin, a colorant and a wax and a shell disposed so as to cover the surface of the core material. The wax is an isoparaffin wax-containing wax having <=60 deg.C melting point and a penetration of >=40 at 25 deg.C. The wax content of the encapsulated toner is 1-20 wt.%.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

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

[0002]

2. Description of the Related Art With the development of electrophotography, various toners have been developed, and the development of a capsule toner for heat and pressure fixing comprising a core material and an outer shell covering the surface of the core material has been advanced. In. In particular, many wax-containing capsule toners have been reported for the purpose of improving the low-temperature fixability, releasability and offset resistance of the toner. However, many waxes are insoluble or hardly soluble in the raw material monomer of the thermoplastic resin constituting the core material, and a decrease in the dispersibility of the wax causes a decrease in the blocking resistance.
Therefore, in order to finely disperse the wax in the core material,
There is a need for a method such as dispersion under heating and high pressure.

[0003]

SUMMARY OF THE INVENTION The present invention provides a capsule toner for heat and pressure fixing having excellent wax dispersibility, good low-temperature fixability, releasability and offset resistance, and also excellent blocking resistance. The purpose is to provide.

[0004]

SUMMARY OF THE INVENTION The present invention provides a heat-fusible core material containing a thermoplastic resin, a colorant and a wax, and an outer shell provided so as to cover the surface of the heat-fusible core material. A heat and pressure fixing capsule toner, wherein the wax contains isoparaffin wax and has a melting point of 6.
The present invention relates to a capsule toner for heat and pressure fixing, which is a wax having a penetration of 40 or more at 0 ° C. or less and 25 ° C. and having a wax content of 1 to 20% by weight in the capsule toner.

[0005]

BEST MODE FOR CARRYING OUT THE INVENTION The heat-fusible core material of the capsule toner for heat and pressure fixing according to the present invention contains an isoparaffin wax and has a melting point of 60 ° C. or less, preferably 10 to 60 ° C. Is 40 or more, preferably 40 to 90. Since such a wax is excellent in solubility of the raw material monomer of the thermoplastic resin constituting the hot-melt core material, no special mixing conditions are required even when the wax is uniformly finely dispersed in the core material. .
Therefore, the encapsulated toner of the present invention in which the wax is finely dispersed in the core material is excellent not only in the properties possessed by the wax such as low-temperature fixing property, releasability and offset resistance, but also in blocking resistance. The wax penetration in the present invention is represented by a value at 25 ° C. as an index.

It is desirable that the wax contains 30 to 100% by weight, preferably 50 to 100% by weight of isoparaffin wax from the viewpoint of blocking resistance. , Normal paraffin wax, polyethylene wax, polypropylene wax, Fischer-Tropsch wax and the like, and these may be contained alone or as a mixture of two or more.

[0007] The content of the wax in the capsule toner is 1% by weight or more from the viewpoint of low-temperature fixability, offset resistance and release property, and 20% by weight or less from the viewpoint of offset resistance and blocking resistance. Yes, preferably 1 to
15% by weight.

[0008] The capsule toner for heat and pressure fixing according to the present invention comprises:
It comprises a heat-fusible core material containing a thermoplastic resin and a colorant in addition to the wax, and an outer shell provided so as to cover the surface of the heat-fusible core material.

Examples of the thermoplastic resin include a vinyl polymer resin, polyester / polyamide, polyamide and the like.
Vinyl polymer resins are preferred.

The raw material monomers for the vinyl polymer resin include styrene compounds such as styrene and α-methylstyrene; ethylenically unsaturated monoolefins such as ethylene and propylene; diolefins such as butadiene; and halovinyls such as vinyl chloride. Vinyl esters such as vinyl acetate and vinyl propionate; ethylenic monocarboxylic acids such as (meth) acrylic acid; alkyl (C1-18) esters of (meth) acrylic acid;
Hydroxyethyl, glycidyl (meth) acrylate,
Esters of ethylenic monocarboxylic acids such as dimethylaminoethyl (meth) acrylate; vinyl ethers such as vinyl methyl ether; vinylidene halides such as vinylidene chloride; and N-vinyl compounds such as N-vinylpyrrolidone.

When polymerizing the raw material monomers of the vinyl polymerizable resin, a polymerization initiator, a crosslinking agent, and the like may be used as necessary.

As the colorant used in the present invention, all of dyes and pigments used as conventional colorants for toners can be used. For example, carbon black, phthalocyanine blue, permanent brown FG,
Brilliant First Scarlet, Pigment Green B, Rhodamine-B Base, Solvent Red 49,
Solvent Red 146, Solvent Blue 35, Quinacridone, Carmine 6B, Disazo Yellow, and the like. These can be used alone or in combination of two or more. The amount of the coloring agent used is the raw material monomer 1 of the thermoplastic resin.
It is preferably about 2 to 25 parts by weight with respect to 00 parts by weight.

The outer shell is preferably made of a hydrophilic resin. Examples of the hydrophilic resin include polyester, hybrid resin, polyamide, polyester polyamide, polyurea and the like. Among these, polyester and hybrid resin are preferable from the viewpoint of fixability and storage stability.

The polyester used in the present invention can be obtained, for example, by the production method described in JP-A-7-175260.

In the present invention, as described in JP-A-8-171231, a hybrid resin is prepared by mixing a mixture of two polymerizable raw material monomers having independent reaction paths, and carrying out two polymerization reactions. Obtained in the same reaction vessel.

The two polymerization reactions proceed in independent reaction paths, and are preferably reactions that produce a condensation polymerization resin and an addition polymerization resin, respectively. Typical examples of the condensation polymerization resin include polyester, polyester polyamide, and polyamide, and typical examples of the addition polymerization resin include a vinyl resin obtained by a radical polymerization reaction.

In the present invention, the acid value of the hydrophilic resin is preferably 0.1 to 30 KOH mg / g, more preferably 5 to 15 KOH mg / g, and the softening point is preferably 90 to 140 ° C., more preferably 95-130 ° C, and the glass transition point is preferably 50-80 ° C, more preferably 55-75 ° C.

The content of the hydrophilic resin is preferably from 0.5 to 100 parts by weight of the raw material monomer of the thermoplastic resin.
It is 50 parts by weight, more preferably 5 to 20 parts by weight.

The capsule toner of the present invention contains a charge control agent, a fluidity improver, a cleaning improver, a conductive filler, a body pigment, a reinforcing filler such as a fibrous substance, an antioxidant, and an antioxidant. And the like may be appropriately contained.

The heat and pressure fixing capsule toner of the present invention comprises:
From the viewpoint of simplification of manufacturing equipment and manufacturing steps, it is preferable to manufacture by a in-situ polymerization method using a raw material monomer of a thermoplastic resin, a coloring agent, a wax, a hydrophilic resin and the like. In the present invention, the in situ polymerization method comprises:
JP-A-6-317925, JP-A-7-17526
This is the same as the polymerization method disclosed in detail in JP-A No. 0, JP-A-9-15900 and the like.

The weight average particle diameter of the capsule toner of the present invention is preferably 3 to 12 μm.

In the present invention, the capsule toner for heat and pressure fixing obtained as described above is used as a precursor particle, and further described in JP-A-6-317925, JP-A-7-175260, and JP-A-9-175260. Seed polymerization described in JP-A-15900 may be performed.

The softening point of the hot-press fixing capsule toner of the present invention is preferably 90 to 150 ° C., and the glass transition point derived from the thermoplastic resin contained in the core material is the storage stability and fixing strength of the capsule toner. 20 ° C to maintain
~ 60 ° C is preferred.

The capsule toner for heat and pressure fixing according to the present invention comprises:
It can be used as a non-magnetic one-component developer or as a two-component developer by mixing with a carrier. For example, JP-A-2-190870 and JP-A-2-16235
No. 6, it is possible to efficiently fix a recording material such as paper by a heat and pressure fixing method.

[0025]

[Example] [Glass transition point of resin] Differential scanning calorimeter "D
It is measured at a heating rate of 10 ° C./min using “SC210” (manufactured by Seiko Instruments Inc.).

[Acid value of resin] Measured according to the method of JIS K0070.

[Softening Point of Toner] Using a Koka type flow tester “CFT-500” (manufactured by Shimadzu Corporation), the temperature at which half of the resin flows out is taken as the softening point (sample: 1 g, heating rate: 6 ° C.) / Min, load: 1.96 MPa, nozzle: 1 mm
φ × 1 mm).

[Melting point of wax] JIS K2235-
Measure according to the method according to 5.3.

[Wax penetration] JIS K2235
-Measure according to the method according to 5.4.

[Content of Isoparaffin Wax in Wax] Measured from the peak area of the gas chromatograph.

Resin Production Example 1 367.5 g of a 2.2 mol adduct of bisphenol A with propylene oxide, 146.4 g of a 2.0 mol adduct of bisphenol A with ethylene oxide, and terephthalic acid 12
6.0 g, dodecenyl succinic anhydride 40.2 g, trimellitic anhydride 77.7 g and dibutyltin oxide 1.4 g
Is reacted at 220 ° C. under a nitrogen atmosphere to obtain ASTM E
When the softening point according to 28-67 reached 110 ° C., the reaction was terminated, and a polyester was obtained. Let the obtained polyester be resin A. The glass transition point of the resin A was 65 ° C., and the acid value was 18 KOH mg / g.

Example 1 154 parts by weight of styrene, 46 parts by weight of 2-ethylhexyl acrylate, grafted carbon black "405P"
26 parts by weight (manufactured by Ryoyu Kogyo Co., Ltd.), 20 parts by weight of resin A, 1.0 part by weight of divinylbenzene, "isoparaffin wax EMW-0001" (manufactured by Nippon Seiro Co., Ltd., content of isoparaffin: 70% by weight, melting point: 49) 1 ° C, penetration: 4
4) 20 parts by weight and 5,2 parts by weight of 2,2'-azobisisobutyronitrile were stirred with a magnetic stirrer, sufficiently dissolved and dispersed to obtain a polymerizable composition.

The obtained polymerizable composition was added to 600 g of an aqueous colloid solution containing 4% by weight of tricalcium phosphate,
Using a “TK homomixer” (manufactured by Tokushu Kika Kogyo Co., Ltd.), the mixture was emulsified and dispersed at 15 ° C. at a rotation speed of 12,000 rpm for 5 minutes, and then reacted at 70 ° C. for 10 hours in a nitrogen atmosphere.

After cooling, 10% by weight of hydrochloric acid was added to dissolve the dispersant, followed by filtration and washing with water.
g for 12 hours, and classified with an air classifier to obtain a capsule toner having a weight average particle size of 8.2 μm. To 100 parts by weight of the obtained capsule toner, 0.4 parts by weight of hydrophobic silica fine powder “R-972” (manufactured by Nippon Aerosil Co., Ltd.) was added and mixed to obtain Toner 1. The softening point of Toner 1 is 1
35.1 ° C.

Example 2 Toner 2 was obtained in the same manner as in Example 1, except that the amount of divinylbenzene used was changed to 0.8 parts by weight and the amount of “isoparaffin wax EMW-0001” was changed to 5 parts by weight. Was. The softening point of Toner 2 was 138.2 ° C.

Comparative Example 1 Comparative toner 1 was obtained in the same manner as in Example 1 except that "isoparaffin wax EMW-0001" was not used. The softening point of Comparative Toner 1 was 164.9 ° C.

Comparative Example 2 Comparative toner 2 was obtained in the same manner as in Example 1 except that the amount of “isoparaffin wax EMW-0001” was changed to 80 parts by weight. The softening point of Comparative Toner 2 is 102.
3 ° C.

Comparative Example 3 In place of "Isoparaffin wax EMW-0001", 20 parts by weight of "Normal paraffin wax 115" (manufactured by Nippon Seiro, melting point: 47 ° C., penetration: 30) were used. Comparative toner 3 was obtained in the same manner as in Example 1. The softening point of Comparative Toner 3 was 134.6 ° C.

Test Example 1 6 parts by weight of each of the obtained toners and 94 parts by weight of spherical ferrite powder coated with a styrene-methyl methacrylate resin having a particle size of 250 to 400 mesh were placed in a polycontainer, and rotated at 150 rpm. For 20 minutes with a container on a roller to prepare a developer. A commercially available electrophotographic copier (printing speed:
255 mm / sec), an image was formed while the fixing temperature was raised from 90 ° C. to 220 ° C. every 10 ° C., and the minimum fixing temperature, releasability and non-offset area were measured by the following methods. Table 1 shows the results.

(1) Minimum fixing temperature The image fixed with a load of 500 g was rubbed five times back and forth with a sand eraser of 15 mm × 7.5 mm through a fixing machine, and the optical reflection density before and after rubbing was measured by a reflection densitometer. "RD
-915 "(manufactured by Macbeth), and the lowest fixing temperature is the temperature of the fixing roller whose ratio (after rubbing / before rubbing) initially exceeds 70%.

(2) Releasability When an image of a chart having a printing rate of 15% consisting of solids, halftones, and characters was printed, the presence or absence of occurrence of a jam was visually observed, and judged according to the following evaluation criteria. I do.

[Evaluation Criteria] A: No jam occurs in the entire evaluation region of 90 to 220 ° C. ×: Jam occurs in any of the evaluation regions of 90 to 220 ° C.

(3) Non-offset area After an image is formed at each temperature, a blank transfer sheet is continuously fed to the fixing roller under the same conditions. The toner area on the white paper is visually observed, and the temperature range from the disappearance of the low-temperature offset to the occurrence of the high-temperature offset is defined as a non-offset area.

Test Example 2 Each of 20 g of the obtained toner was put in a plastic container and sealed.
The degree of agglomeration after standing in a thermostat at 50 ° C. for 48 hours was visually observed, and the blocking resistance was evaluated according to the following criteria. Table 1 shows the results.

[Evaluation Criteria] A: No or almost no aggregation. X: Aggregation is observed partially or entirely.

[0046]

[Table 1]

From the above results, it is understood that the toners obtained in Examples 1 and 2 are excellent not only in low-temperature fixability, release property and offset resistance but also in blocking resistance. On the other hand, the toner of Comparative Example 1 containing no wax lacks low-temperature fixability, releasability, and offset resistance, and Comparative Example 2 containing a large amount of wax.
It can be seen that the toner of Comparative Example 3 lacks offset resistance and blocking resistance, and the toner of Comparative Example 3 containing a wax containing normal paraffin as a main component lacks blocking resistance.

[0048]

According to the present invention, it is possible to provide a hot and pressure fixing capsule toner which is excellent in wax dispersibility, has good low-temperature fixability, releasing property and offset resistance and also has excellent blocking resistance. It has become possible.

Claims (2)

[Claims] 1. A hot-press fixing capsule comprising a heat-fusible core material containing a thermoplastic resin, a colorant and a wax, and an outer shell provided so as to cover the surface of the heat-fusible core material. A toner, wherein the wax contains isoparaffin wax and has a melting point of 60 ° C. or less, a penetration at 25 ° C. of 40 or more, and a wax content of 1 to 20% by weight in the capsule toner. Capsule toner for heat and pressure fixing. 2. The capsule toner according to claim 1, wherein the outer shell is made of a polyester or a hybrid resin.