JPH04250464A - Toner for flash fixing - Google Patents

Abstract

PURPOSE:To provide a toner for developing an electrostatic image fit for flash fixing. CONSTITUTION:A mixture of epoxy resin with crystalline polyester resin or a block or graft copolymer consisting of the structural units of both the resins is used as binder resin for a toner.

Description

[Detailed description of the invention]

0001

[Field of Industrial Application] The present invention relates to the fixing properties of toner for developing electrostatic images used in electrophotography, electrostatic recording, etc.
Regarding flash fixation.

0002

[Prior Art] Fixing of electrostatic charge toner images includes melt fixing of the toner using heat and pressure fixing of toner particles between paper fibers.The advantage of pressure fixing is that The high cost of the pressure mechanism, the increased weight, and the imperfect fixing performance have all offset this, and melting fixing has become the mainstream of fixing.

[0003] There are two methods for melt fixing: a method using conduction heating using a heat roller, which has been commonly used, and a method using radiation heating.

The conduction heating method has drawbacks such as the need for a long time to heat up the heat roller to the fixing temperature and the offset of the toner to the roller, and even with radiation heating, there are problems such as burning of the copy. It is dangerous.

[0005] To address the above-mentioned drawbacks of radiant heating, a flash fixing method has been developed in which radiant heating is performed in a flash manner (
Special Publication No. 44-13116, No. 44-13117),
It has many advantages, such as a very short heat-up time until the toner melts, little wasted energy consumption, and no relation to the offset phenomenon.

[0006] Flash fixing uses high-intensity light emitted from xenon gas, halogen gas, etc. to fix a toner image at a rate of 0.1~
It is irradiated for 1 millisecond and melts and fixes by applying a heat amount of about 0.5 to 10 joules/cm 2 .

[0007] As a developer toner capable of flash fixing, it softens with a heat amount of about 0.5 to 10 Joules/cm2.
It is necessary to satisfy requirements such as melting and not decomposing by irradiation and producing no toxic gas or odor, and several proposals have already been made.

For example, focusing on the binder resin of the toner, selecting an epoxy resin whose composition meets specific requirements and a resin such as bisphenol A used in combination with the epoxy resin, and having a predetermined melting point,
Proposals to provide melt viscosity (JP-A Nos. 53-91746, 56-30139, 58-168053, 58
-203451, 58-215660, etc.).

Furthermore, from the viewpoint that it is not necessary to melt the toner resin itself and that it is sufficient to glue the toner particles as a toner image, it is possible to melt compounds such as lubricants by paying attention to their melting point and melt viscosity. A technique for using it as a glue has been disclosed (
JP-A-57-79957, JP-A No. 63-30857).

However, the disclosed technique focusing on the binder has poor fixing in low-energy irradiation, and even when the fixing performance is good, the fluidity and aggregation resistance of the toner are poor. Also, those intended for adhesive properties have poor fluidity and agglomeration resistance, which poses a practical problem.

Furthermore, if the toner image is kept in close contact with a PVC surface such as a PVC bag, the toner image will adhere to the PVC surface and be scraped off, which will completely destroy the value of the copy from the user's perspective, causing problems such as flash fixation. The toner image is remarkable.

0012

OBJECTS OF THE INVENTION The purpose of the present invention is to provide toner that can be sufficiently and reliably fixed by the flash fixing method, and (2) provide high-resolution, photorealistic images without uneven development. (3) Highly durable toner that will not be decomposed by flash light irradiation.
Providing a toner that does not produce toxic gases or strange odors; (4) a toner that has good fluidity and does not cause blocking (agglomeration resistance); and (5) a toner that does not adhere to PVC surfaces (vinyl chloride resistance). It is in.

[0013]

SUMMARY OF THE INVENTION The object of the present invention is to provide a toner for flash fixing which contains at least a binder resin and a colorant, the binder resin containing an epoxy resin and a crystalline polyester resin. achieved.

In the above embodiment, the softening point of the epoxy resin is 60 to 130°C, the melting point of the crystalline polyester resin is 50 to 120°C, and the epoxy resin (EP
) and the crystalline polyester resin (CPES) (EP/CPES) is preferably (95-50)/(5-50).

The present invention further provides a toner containing at least a binder resin and a colorant, wherein the binder resin is a block copolymer or graft copolymer of an epoxy resin structural unit and a crystalline polyester resin structural unit. It may be an aspect characterized by.

Various known epoxy resins can be used as the epoxy resin used in the present invention, and a typical epoxy resin includes bisphenol A type epoxy resin produced by a condensation reaction of bisphenol A and epichlorohydrin. .

Epoxy resins include "Epikoat resin" (manufactured by Yuka Ciel Epoxy Co., Ltd., etc.), which is one of the famous commercially available epoxy resins, and "Epicoat 828" (epoxy equivalent: 184 to 194, molecular weight: Approximately 38
0) to Epicoat 1009” (epoxy equivalent weight 240
0 to 3300, molecular weight approximately 3750) can be used, and the epoxy resin is not limited to "Epicote resin", but many other commercially available products or equivalent in-house products can be used. . In addition, there are also methods that use novolac instead of bisphenol A, and methods that use peracetic acid to introduce epoxy groups into unsaturated groups of unsaturated compounds such as cyclopetadiene, cyclohexane derivatives, polybutadiene, and drying oil. Examples include those having properties different from bisphenol A-based resins.

From the viewpoint of fixing properties, the softening point is 60 to 130°C.
gives good results.

Next, as the crystalline polyester according to the present invention, Japanese Patent Application Laid-open Nos. 63-27855 and 63-27856
The one listed in the number is used. A melting point of 50-120°C gives good results.

The ratio of the epoxy resin EP and CPES used is EP:CPES=95-50:5-50 (weight ratio). If the CPES content is less than 5, the fixing performance will be poor;
If it exceeds 0, the fluidity of the toner will deteriorate and the rise of charging will also be poor.

When the binder resin is a block or graft copolymer of an epoxy resin and a crystalline polyester, the toner has good properties such as fluidity and chargeability. The synthesis method is to combine the epoxy group in the epoxy resin and the -OH of the CPES terminal.
The chemical bond is made by reaction with a group or a -COOH group.

Synthesis can be carried out by known methods, such as reaction using heat during kneading or reaction in a solution, but the reaction efficiency is high if the two resins are dissolved in an organic solvent and reacted by heating. .

Next, the toner of the present invention will be explained. The toner of the present invention is composed of a binder resin containing the above-mentioned epoxy resin and crystalline polyester resin component, and toner components such as a colorant, a magnetic material used as necessary, and a property improver. . In addition, in the toner of the present invention, other resins may be used in combination as the binder resin in addition to the above-mentioned specific binder resin. but,
The content of the specific binder resin in the entire binder resin is preferably 30% by weight or more,
Particularly preferred is a range of 50 to 100% by weight.

Colorants used in toner include, for example, carbon black, nigrosine dye (C.I.No.
50415B), Aniline Blue (C.I.No.50
405), Calco Oil Blue (C.I.No.azo
ic Blue 3), Chrome Yellow (C.I.No.
．． 14090), Ultramarine Blue (C.I.No.
．． 77103), DuPont Oil Red (C.I.No.
．． 26105), Quinoline Yellow (C.I. No. 4)
7005), methylene blue chloride (C.I.No.
．． 52015), Phthalocyanine Blue (C.I.No.
．． 74160), malachite green oxalate (C
．． I. No. 42000), Rose Bengal (C.I.
No. 45435), mixtures thereof, and the like. The amount of colorant used is usually in the range of 0.1 to 20 parts by weight, particularly 0.5 to 20 parts by weight, per 100 parts by weight of toner.
10 parts by weight is preferred.

[0025] The magnetic material used in the toner may include ferrite, magnetite, iron, cobalt, nickel, or other ferromagnetic metals or alloys, compounds containing these elements, or suitable materials that do not contain ferromagnetic elements. Alloys that become ferromagnetic through heat treatment, such as alloys called Heusler alloys containing manganese and copper, such as manganese-copper-aluminum, manganese-copper-tin, chromium dioxide, and others. Can be done. For example, when obtaining a black toner, magnetite is preferred because it is black in itself and also functions as a coloring agent. Also, when obtaining color toner,
It is preferable to use a material with little darkness, such as metal iron. Some of these magnetic materials also function as a coloring agent, and in that case, they may also serve as a coloring agent. These magnetic substances are contained in the form of fine powder with an average particle size of 0.1 to 1 μm. In magnetic toner, the content is preferably 20 to 70% by weight, particularly 40 to 70% by weight of the toner.
0% by weight is preferred.

[0026] Characteristic improvers used in toner include:
These include fixability improvers, charge control agents, etc.

Examples of fixing property improvers include polyolefin waxes, fatty acid metal salts, fatty acid esters and fatty acid ester waxes, partially saponified fatty acid esters, higher fatty acids, higher alcohols, liquid or solid paraffin waxes, polyamide waxes, and polyvalent waxes. Alcohol esters, silicone varnishes, aliphatic fluorocarbons, etc. can be used. In particular, the softening point (ring and ball method JIS K
2531) is preferably 60 to 150°C.

As the charge control agent, conventionally known ones can be used. Examples include nigrosine dyes and metal-containing dyes.

In one example of the toner manufacturing method of the present invention, a binder resin containing at least the above-mentioned specific binder resin and toner components such as a colorant are mixed, and the mixture is melt-kneaded using, for example, an extruder. After cooling, it is finely pulverized using a jet mill or the like, and then classified to produce a toner having a desired particle size.

[0030] In another example of the toner manufacturing method of the present invention, the toner is melt-kneaded using an extruder or the like in the same manner as described above and then sprayed or dispersed in a liquid using a spray dryer or the like in the melted state. A toner with a desired particle size is manufactured by the following steps.

Further, in the present invention, the toner may be constituted by adding and mixing inorganic fine particles such as a fluidity improver to the toner obtained as described above.

[0032] Such inorganic fine particles preferably have a primary particle diameter in the range of 5 nm to 2 μm, particularly 5 to 500 nm. In addition, the BET specific surface area of inorganic fine particles is 20
The range of ~500 m2/g is preferred.

[0033] The addition ratio of inorganic fine particles is 0 to the total toner.
．． The range is preferably from 0.01 to 5% by weight, and from 0.01 to 2.0% by weight.

Examples of constituent materials of the inorganic fine particles include silica, alumina, titanium oxide, barium titanate, magnesium titanate, calcium titanate, strontium titanate, zinc oxide, silica sand, clay, mica, wollastonite,
Examples include diatomaceous earth, chromium oxide, cerium oxide, red iron oxide, antimony trioxide, magnesium oxide, zirconium oxide, barium sulfate, barium carbonate, calcium carbonate, silicon carbide, and silicon nitride. Among these, silica fine powder is particularly preferred.

The silica fine powder is a fine powder having Si--O--Si bonds, and may be produced by either a dry method or a wet method. In addition to anhydrous silicon dioxide, aluminum silicate, sodium silicate, potassium silicate,
Any of magnesium silicate, zinc silicate, etc. may be used, but S
Those containing iO2 in a proportion of 85% by weight or more are preferable.

Specific examples of these fine silica powders include various commercially available silicas, but those having hydrophobic groups on the surface are preferred, such as AEROSIL R-972,
Examples include R-974, R-805, R-812 (manufactured by Aerosil), and Turrax 500 (manufactured by Talco). In addition, silica fine powder treated with a silane coupling agent, a titanium coupling agent, silicone oil, silicone oil having an amine in its side chain, etc. can also be used.

[0037]

[Example] - Epikote 1002 (manufactured by Yuka Shell Epoxy Co., Ltd.) with an epoxy resin softening point of 80°C was used.

・Crystalline polyester Crystalline polyester 1 1500 g of sebacic acid and 96 hexamethylene glycol
4 g and a capacity 5 with a thermometer, stainless steel stirrer, glass nitrogen inlet tube and down-flow condenser.
This flask was then placed in a mantle heater, and nitrogen gas was introduced through a glass nitrogen inlet tube to raise the temperature while maintaining an inert atmosphere inside the reactor. Then, 13.2 g of p-toluenesulfonic acid was added and reacted at a temperature of 150°C. The amount of distilled water is 2
The reaction was stopped when the volume reached 50 ml, and the reaction system was cooled to room temperature to obtain a crystalline polyester 1 made of polyhexamethylene sebacate having a hydroxyl group at the end of the molecule. The melting point Tm of this crystalline polyester 1 (differential scanning calorimeter "D"
Value measured with "SC-20" (manufactured by Seiko Electronics Industries, Ltd.). (same below) is 64℃, weight average molecular weight Mw is 1
It was 4,000.

Crystalline polyester 2 Same as crystalline polyester 1, melting point Tm=72°C,
Polyethylene sebacate with a weight average molecular weight Mw=12,800 was obtained.

Examples 1 to 3 The above epoxy resin and crystalline polyester resin were mixed in the proportions shown in Table 1 to prepare toners.

[0041]

[Table 1]

[0042] Epoxy resin

Listed amount Crystalline polyester 1 or 2
Listed amount carbon black

10 parts paraffin wax

Tripartite alkylene bis fatty acid amide
3
20 minutes of materials were placed in a V-type mixer, mixed for 20 minutes, melt-kneaded using a twin-screw extruder, cooled, coarsely ground using a Willey mill to obtain a 2mm mesh pass product, and then finely ground using a supersonic jet mill. Then, fine particles with a particle size of 5 μm or less were removed using an air classifier to obtain colored particles with an average particle size of 11 μm.

Toners 1 to 3 of the present invention were prepared by mixing 0.8 parts of silica and 0.05 parts of zinc stearate with 100 parts of the colored particles using a V-type mixer.

Example 4 15 parts of crystalline polyester 1, 85 parts of Epikote 1007 (manufactured by Yuka Shell Epoxy Co., Ltd.) with a softening point of 125°C, and 100 parts of xylene were placed in a separable flask with a capacity of 3 liters, and the temperature The mixture was refluxed at 135°C for 1 hour, and then xylene was distilled off to obtain a graft copolymer with a softening point of 105°C. A toner was experimentally produced in the same manner as in Example 1.

Comparative Example-(1) Epikote 100 with a softening point of 125°C as a binder resin
A toner was experimentally produced in the same manner as in Example 1, except that EXAMPLE 7 (epoxy resin) was used.

Comparative Example-(2) Only crystalline polyester 1 was used as the binder resin,
A toner was produced as a prototype in the same manner as in Example 1.

The following characteristics were evaluated for the above toner and are shown in Table 2.

Evaluation (1) Flash fixability Each toner was mixed with a coated carrier in which a fluorinated alkyl methacrylate polymer was coated on a ferrite core material with an average particle size of 80 μm at a ratio of 2% by weight, and the content ( A two-component developer having a toner concentration of 5% by weight was prepared.

[0049] A latent image carrier made of an organic photoconductive semiconductor;
Electrophotographic copying machine "U-" equipped with a developing device for two-component developer
Bix 1550MR (manufactured by Konica Corporation) to form a so-called solid black copy image, and a fixing device equipped with a reflector with an area of 179 cm2 and a xenon lamp (manufactured by Ushio Inc.) to produce a pulse duration of 1 millisecond and a flash. The energy from the lamp is applied to the surface of the image-bearing sheet by 2
．． Flash fixing was performed under the condition of 5 joules/cm2.

After rubbing the edges of the obtained fixed toner image with a rubbing tester applying a constant load, the residual rate of the image at the edge was measured with a microdensitometer, and the residual rate was 80% or more. The fixation state indicating the fixing condition was rated "○", and the case where the fixation state was lower was rated "x".

(2) Resistance to vinyl chloride of toner The resistance to vinyl chloride of toner was determined by applying a load of 100 g/cm2 to the surface of a printed matter formed by a continuous copy test with a cover film made of commercially available polyvinyl chloride, and at a temperature of 70°C.
The cover film was left to stand for 3 hours under an atmosphere of 100 mL, and then cooled to room temperature, and the cover film was peeled off from the printed matter.The degree of toner transfer to the cover film was visually determined. The results of the evaluation are indicated as "○" if no metastasis is observed, "△" if a small amount of metastasis is observed, and "×" if metastasis is observed.

(3) Fluidity of toner Taking advantage of the fact that powder resistance with higher fluidity has a lower degree of compression,
Each toner was loosely filled from above into a container with a diameter of 28 mm and a volume of 100 ml, and its weight was determined to determine the static bulk density of the toner. In the evaluation, a static bulk density of 0.40 g/ml or more was rated "○", and a static bulk density of less than 0.40 g/ml was rated "x".

(4) Cohesive property of toners 2 g of each toner was taken into a sample tube, tapped 500 times with a tap densityer, and then the temperature was 60°C and the relative humidity was 34°C.
% atmosphere for 2 hours, and then separated using a 48-mesh sieve, and the proportion of aggregates remaining on the sieve was measured.

[0054]

[Table 2]

As is clear from Table 2, the toner of the comparative example has no practical use. Furthermore, the toner of the example did not decompose by flashing, and therefore did not generate any toxic gas or odor.

[0056]

According to the present invention, a toner which is highly practical as a toner for flash fixing can be obtained.

Claims (3)

[Claims] 1. A toner for flash fixing comprising at least a binder resin and a colorant, the binder resin containing an epoxy resin and a crystalline polyester resin. [Claim 2] The epoxy resin has a softening point of 60 to 1.
30℃, the melting point of crystalline polyester resin is 50-120
The flash fixing toner according to claim 1, wherein the content weight ratio EP/CPES of the epoxy resin (EP) and the crystalline polyester resin (CPES) is (95 to 50)/(5 to 50). . 3. A toner containing at least a binder resin and a fixing agent, wherein the binder resin is a block copolymer or a graft copolymer of an epoxy resin structural unit and a crystalline polyester resin structural unit. Flash fixing toner.