JP2920423B2 - Flash fixing toner - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

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

[0002]

2. Description of the Related Art For fixing a toner image of an electrostatic charge image, there are two methods: melting and fixing of toner by heat, and pressing and fixing of toner particles between paper fibers by pressure. The shadow has become thinner, offset by the high cost, weight increase, and imperfect fixability required for the pressure mechanism, and fusion fixing has become the mainstream of fixing.

[0003] Melt fixing includes a conventional method using conduction heating by a heat roller and a method using radiation heating.

[0004] The conduction heating method has disadvantages such as a long time required to heat up a heat roller to a fixing temperature, an offset of a toner to a roller, and the like. Has danger.

In order to solve the above-mentioned drawback of radiation heating, a flash fixing method has been developed in which radiation heating is performed in a flash manner (Japanese Patent Publication Nos. 44-13116 and 44-13117), and the heat-up time until the toner melts is extremely long. It has many advantages, such as being short, having little energy consumption, and being completely unrelated to the offset phenomenon.

In flash fixing, for example, light having a high luminous intensity, such as xenon gas or halogen gas, is applied to a toner image by 0.1 to 1%.
Irradiation for milliseconds gives a heat amount of about 0.5 to 10 joules / cm ² to fuse and fix.

[0007] As a developer toner capable of flash fixing, it satisfies requirements such as softening and melting with a heat amount of about 0.5 to 10 joules / cm ² , and decomposing by irradiation so as not to generate toxic gas or unpleasant odor. It is necessary, and there are already several proposals.

For example, paying attention to the binder resin of the toner, an epoxy resin having specific requirements in its composition and a resin such as bisphenol A used together with the resin are selected.
Proposal for giving melt viscosity (JP-A-53-91746, JP-A-56-30139)
Nos. 58-168053, 58-203451, 58-215660).

Further, it is not necessary to melt the toner resin itself, and it is sufficient to glue the toner particles as a toner image. Therefore, a compound such as a lubricant focused on the melting point and melt viscosity is melted. Techniques for use as a glue are disclosed (JP-A-57-79957 and JP-A-63-30857).

[0010] However, the disclosed technique focusing on the binder is defective in fixing at low energy irradiation, and when the fixing property is good, the fluidity and aggregation resistance of the toner are poor. In addition, those intended for the effect of gluing similarly have poor fluidity and cohesion resistance and have practical problems.

Further, if the toner image is brought into close contact with a PVC surface such as a PVC bag or the like, the toner image adheres to the PVC surface and is scraped off. Notable for toner images.

[0012]

SUMMARY OF THE INVENTION The object of the present invention is to address the above-mentioned problems relating to flash fixing; (1) a toner which is sufficiently and reliably fixed by a flash fixing method; and (2) a real image having a good resolution without developing unevenness. (3) without being decomposed by flash light irradiation,
Toner that does not generate toxic gas and off-flavor, (4) toner that has good fluidity and does not cause blocking (aggregation resistance), and (5) toner that does not cause adhesion to PVC surfaces (PVC resistance) It is in.

[0013]

SUMMARY OF THE INVENTION An object of the present invention is to provide a toner for flash fixing, characterized in that the toner contains at least a binder resin and a colorant, wherein the binder resin contains an epoxy resin and a crystalline polyester resin. Achieved.

In the above embodiment, the epoxy resin has a softening point of 60 to 130 ° C., the crystalline polyester resin has a melting point of 50 to 120 ° C., and the epoxy resin (EP) and the crystalline polyester resin (CPE _S ) EP / CPE _S (9
(5-50) / (5-50).

Further, according to the present invention, in a toner containing at least a binder resin and a colorant, the binder resin is a block copolymer or a graft copolymer of an epoxy resin structural unit and a crystalline polyester resin structural unit. May be adopted.

As the epoxy resin used in the present invention, various known epoxy resins can be used, and a typical epoxy resin is a bisphenol A type epoxy resin produced by a condensation reaction between bisphenol A and epichlorohydrin. .

Epoxy resins include “Epicoat resin” (produced by Yuka Shell Epoxy Co., Ltd.) which is one of the famous epoxy resins on the market.
From 828 ”(epoxy equivalent 184-194, molecular weight about 380), Epicoat 1009” (epoxy equivalent 2400-3300, molecular weight about 37)
Epoxy resins of all types up to 50) can be used, and the epoxy resin is not limited to “epicoat resin”, and many other commercial products or its own products can be used. Incidentally, there is also a method using novolak in place of bisphenol A, or a method of introducing an epoxy group using an unsaturated compound, for example, cyclopetadiene or a cyclohexane derivative, polybutadiene, an unsaturated group such as drying oil, using peracetic acid, Those having properties different from those of the bisphenol A-based resin are exemplified.

From the viewpoint of fixability, a softening point of 60 to 130 ° C. gives good results.

Next, as the crystalline polyester according to the present invention, those described in JP-A-63-27855 and JP-A-63-27856 are used. Melting points of 50-120 ° C give good results.

The ratio of epoxy resin EP to CPE _S used is EP: CPE
_S = 95-50: 5-50 (weight ratio). CPE _S content is 5
Below, the fixability becomes poor, and when it exceeds 50, the fluidity of the toner becomes poor, and the rise of charging becomes poor.

When the binder resin is a block or graft copolymer of an epoxy resin and a crystalline polyester, the characteristics of the toner such as fluidity and chargeability are improved. In the synthesis method, an epoxy group in an epoxy resin is chemically bonded to a —OH group or —COOH group of a CPE _S terminal by a reaction.

The synthesis may be performed by a known method, and includes a reaction by heat during kneading, a reaction in a solution, and the like. The reaction efficiency is high when two kinds of resins are dissolved in an organic solvent and reacted by heating. .

Next, the toner of the present invention will be described.
The toner of the present invention comprises the above-described binder resin containing an epoxy resin and a crystalline polyester resin component, and a toner component such as a colorant, a magnetic material used as necessary, and a property improving agent. . In the toner of the present invention, other resins may be used as the binder resin in addition to the above specific binder resin. But,
The content of the specific binder resin in the entire binder resin is preferably 30% by weight or more, and particularly preferably in the range of 50 to 100% by weight.

Examples of the colorant used in the toner include carbon black and nigrosine dye (CI No. 50415).
B), aniline blue (CINo. 50405), calco oil blue (CINo. Azoic Blue 3), chrome yellow (C.
I.No.14090), Ultramarine Blue (CINo.7710)
3), Dupont oil red (CINo.26105), quinoline yellow (CINo.47005), methylene blue chloride (CINo.52015), phthalocyanine blue (CINo.7)
4160), Malachite Green Oxalate (CINo.420)
00), Rose Bengal (CINo. 45435), and mixtures thereof. The amount of colorant used is
It is usually in the range of 0.1 to 20 parts by weight, particularly preferably 0.5 to 10 parts by weight, per 100 parts by weight.

The magnetic material used in the toner does not contain ferromagnetic metals or alloys such as ferrite and magnetite, cobalt, nickel and the like, or compounds containing these elements or ferromagnetic elements. Alloys that become ferromagnetic when subjected to heat treatment, for example, alloys of a type called a Heusler alloy containing manganese and copper, such as manganese-copper-aluminum and manganese-copper-tin, or chromium dioxide, and the like. Can be. For example, in the case of obtaining a black toner, magnetite, which is itself black and also functions as a colorant, is preferable. When a color toner is to be obtained, a toner having less blackness such as metallic iron is preferable. Some of these magnetic materials also function as a colorant, and in such a case, they may also be used as a colorant. These magnetic substances are contained in the form of fine powder having an average particle size of 0.1 to 1 μm. The content of the magnetic toner is preferably 20 to 70% by weight of the toner, particularly preferably 40 to 70% by weight.

As the property improving agent used in the toner,
There are a fixability improving agent, a charge control agent and the like.

Examples of the fixability improver include polyolefin wax, fatty acid metal salt, fatty acid ester and fatty acid ester wax, partially saponified fatty acid ester, higher fatty acid, higher alcohol, fluid or solid paraffin wax, polyamitic wax, and polyvalent wax. Alcohol esters, silicone varnishes, aliphatic fluorocarbons and the like can be used. In particular, the softening point (ring and ball method JIS K 253
Wax of 1) at 60 to 150 ° C. is preferred.

As the charge control agent, those conventionally known can be used. For example, a nigrosine dye, a metal-containing dye and the like can be mentioned.

In one example of the method for producing a toner of the present invention, a binder resin containing at least the above specific binder resin and a toner component such as a colorant are mixed, and the mixture is melted and kneaded by, for example, an extruder. After cooling, the mixture is finely pulverized by a jet mill or the like and classified to produce a toner having a desired particle size.

In another example of the method for producing a toner according to the present invention, in the same manner as described above, what is melt-kneaded from an extruder or the like is sprayed or dispersed in a liquid in a molten state by a spray dryer or the like. To produce a toner having a desired particle size.

In the present invention, the toner obtained as described above may be mixed with inorganic fine particles such as a fluidity improver to form a toner.

As such inorganic fine particles, those having a primary particle diameter of 5 nm to 2 μm, particularly preferably 5 to 500 nm are preferable. The BET specific surface area of the inorganic fine particles is preferably in the range of 20 to 500 m ² / g.

The addition ratio of the inorganic fine particles is 0.1% of the whole toner.
The range is preferably from 01 to 5% by weight and from 0.01 to 2.0% by weight.

As the constituent material of the inorganic fine particles, for example, silica, alumina, titanium oxide, barium titanate, magnesium titanate, calcium titanate, strontium titanate, zinc oxide, silica sand, clay, mica, wollastonite,
Diatomaceous earth, chromium oxide, cerium oxide, red iron oxide, antimony trioxide, magnesium oxide, zirconium oxide, barium sulfate, barium carbonate, calcium carbonate, silicon carbide, silicon nitride, and the like can be given. Of these, silica fine powder is particularly preferred.

The silica fine powder is a fine powder having a Si—O—Si bond, and may be manufactured by either a dry method or a wet method. In addition to anhydrous silicon dioxide, aluminum silicate, sodium silicate, potassium silicate, magnesium silicate, it may be any of such zinc silicate, the SiO ₂ 85
It is preferable that the content be contained at a ratio of not less than weight%.

Specific examples of these silica fine powders include various commercially available silicas, and those having a hydrophobic group on the surface are preferable. For example, AEROSIL R-972, R-974, R-80
5, R-812 (above, manufactured by Aerosil), Tarax 500
(Manufactured by Talco) and the like. In addition, fine powder of silica treated with a silane coupling agent, a titanium coupling agent, silicon oil, silicon oil having an amine in a side chain, or the like can also be used.

[0037]

[Example]-Epoxy resin Epicoat 1002 (manufactured by Yuka Shell Epoxy Co.) with a softening point of 80 ° C is used.

Crystalline Polyester Crystalline Polyester 1 1500 g of sebacic acid and 964 g of hexamethylene glycol were placed in a 5-liter round bottom flask equipped with a thermometer, a stainless steel stirrer, a glass nitrogen inlet tube and a falling condenser. Then, the flask was placed in a mantle heater, and nitrogen gas was introduced through a glass nitrogen introducing tube to raise the temperature while keeping the inside of the reactor under an inert atmosphere. Then add 13.2 g of p-toluenesulfonic acid and add
The reaction was performed at 50 ° C. When the amount of distilled water reached 250 ml, the reaction was stopped, and the reaction system was cooled to room temperature to obtain a crystalline polyester 1 comprising polyhexamethylene sebacate having a hydroxyl group at a molecular terminal. The melting point Tm of this crystalline polyester 1 (a value measured by a differential scanning calorimeter “DSC-20” (manufactured by Seiko Instruments Inc .; the same applies hereinafter)) was 64 ° C.
The weight average molecular weight Mw was 14,000.

Crystalline polyester 2 Polyethylene sebacate having a melting point Tm = 72 ° C. and a weight average molecular weight Mw = 12,800 was obtained in the same manner as the crystalline polyester 1.

Examples 1 to 3 The above-mentioned epoxy resin and crystalline polyester resin were mixed at the ratios shown in Table 1 to produce a toner.

[0041]

[Table 1]

[0042] Epoxy resin
Listed amount Crystalline polyester 1 or 2
Listed amount Carbon black
10 parts paraffin wax
3 parts alkylene bis fatty acid amide
3 parts or more of the materials are put into a V-type mixer, mixed for 20 minutes, melt-kneaded by a twin-screw extruder, cooled, coarsely pulverized by a wheely mill to form a 2 mm mesh pass product, and further finely mixed by a supersonic jet mill. Crushed, then the particle size of 5 by air classifier
By removing fine powder having a particle size of μm or less, colored particles having an average particle size of 11 μm were obtained.

To 100 parts of the colored particles, 0.8 part of silica and 0.05 part of zinc stearate were mixed by a V-type mixer to produce Toners 1 to 3 of the present invention.

Example 4 Crystalline polyester 1; 15 parts, 85 parts of Epicoat 1007 (manufactured by Yuka Shell Epoxy Co.) having a softening point of 125 ° C., xylene 100
Part of the mixture in a separable flask having a capacity of 3 l.
The mixture was refluxed at 5 ° C. for 1 hour, and then xylene was distilled off to obtain a graft copolymer having a softening point of 105 ° C. A trial production of a toner was performed in the same manner as in Example 1.

Comparative Example (1) A toner was trial-produced in the same manner as in Example 1 except that only Epicoat 1007 (epoxy resin) having a softening point of 125 ° C. was used as a binder resin.

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

The characteristics of the toner described above were evaluated and the results 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 having 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.

A latent image carrier comprising an organic photoconductive semiconductor,
Electrophotographic copier "U-" equipped with a developing device for two-component developer
Bix 1550MR ”(manufactured by Konica Corporation) forms a so-called solid black copy image, and has a pulse duration of 1 millisecond by a fixing device equipped with a reflector of 179 cm ² and a xenon lamp (manufactured by Ushio Inc.). Flash fixing was performed on the surface of the image bearing sheet with the energy of a flash lamp at 2.5 joules / cm ² .

After rubbing the end of the obtained fixed toner image with a constant load using a rubbing tester, the residual ratio of the image at the end was measured with a microdensitometer, and the residual ratio was 80% or more. Is indicated by “○”, and the fixing state below “×” is indicated by “×”.

(2) PVC Resistance of Toner The PVC resistance was measured by applying a load of 100 g / cm ² by applying a cover film made of a commercially available polyvinyl chloride to the surface of the printed matter formed by the continuous copy test, and applying a load of 100 g / cm ^2. The cover film was allowed to stand for 3 hours in an atmosphere of ° C., then cooled to room temperature, and the cover film was peeled off from the printed matter, and the degree of transfer of the toner to the cover film was visually determined. Regarding the result of the judgment, “○” indicates that no metastasis is observed, “△” indicates that a trace amount of metastasis is observed, and “×” indicates that metastasis is observed.

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

(4) Cohesiveness of toner 2 g of each toner is placed in a sample tube, and is tapped with a tap capacitor.
After tapping 500 times, the battery was discharged for 2 hours in an atmosphere of a temperature of 60 ° C. and a relative humidity of 34%, and then separated by a 48-mesh sieve, and the ratio of aggregates remaining on the sieve was measured.

[0054]

[Table 2]

As is clear from Table 2, the toner of Comparative Example has no practical use. Further, the toner of the example was not decomposed by flashing, and thus did not generate toxic gas or off-flavor.

[0056]

According to the present invention, a toner having high utility as a flash fixing toner can be obtained.

────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Hiroyuki Takagaki Inspector Yaichi Inoue, Konica Corporation, 2970 Ishikawa-cho, Hachioji-shi, Tokyo (56) Reference JP-A-58-215660 (JP, A) JP-A-2-71276 (JP, A) JP-A-50-87032 (JP, A) JP-A-56-65146 (JP, A) (58) Fields investigated (Int. Cl. ⁶ , DB name) G03G 9 / 087

Claims (3)

(57) [Claims] 1. A flash fixing toner comprising at least a binder resin and a colorant, wherein the binder resin contains an epoxy resin and a crystalline polyester resin. 2. 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., the content weight ratio EP / CPE _S of the epoxy resin (EP) and the crystalline polyester resin (CPE _S) is (95-50) / (5 Five
2. The flash fixing toner according to claim 1, which is 0). 3. A toner containing at least a binder resin and a colorant , 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.