KR840000557B1 - Electro photography - Google Patents

Abstract

Electronic photo is treated by means of developing the electronic picture with toner fine particles(I) and fixing through irradiation with high-energy ultraviolet or visible light. I contains 0.6 - 8 wt % carbon, 0 -5 wt % dye, 62 - 99.4 wt % resin of bis-phenol Alepichlorohydrine epoxy resin, of which melting point is 60 - 160oC, epoxy equivalent wt. is 450 - 5500, and average molecular wt. is 900 - 8250. The fixing agent is 1 - 20 wt % C20 - C30 carboxylic acid ester such as montanic acid wax ester.

Description

Electrophotographic Processing Method

1 is a gas chromatogram of a gas mixture released when a phase developed with the toner of the present invention is settled by flash fixing.

2 is a gas chromatogram of a gas mixture released when a phase developed with a toner comprising a conventional styrene / butyl acrylate ester is settled by flash fixing.

The present invention relates to an electrophotographic processing method in which an image developed with toner particles is fixed by flash fixing.

In a conventional electrophotographic processing method used in electrophotographic apparatuses such as printers, facsimiles, and copiers, images developed with a toner are usually fixed using a heat oven (OVEN) or a thermal roll. However, the toners used in these conventional electronic test processes are not suitable for the processing method of fixing the developed image by flash fixing. The term "flash fixation" as used herein refers to a fixing process in which the toner phase is settled by rapidly raising the toner temperature to a temperature at which the toner can melt by irradiating the toner phase with high energy ultraviolet rays or visible light. .

Conventional toners are generally described in, for example, Japanese Patent Application Publication Nos. 17,434 / 72, 17, 435/72, 8, 141, / 73, 16, 646/73, 75, 033/73, 78, 936/73, 79, 639 / 73, 90, 238/73, 90, 132/74, 44, 836/75, 23, 941/77, and contains a resin binder of a styrene / acrylic acid ester copolymer system.

If a toner made of this styrene / acrylic acid ester copolymer is used in the electrophotographic processing in which the toner image is developed and fixed by flash fixing, the styrene / acrylic acid ester copolymer tends to be of poor quality.

In other words, the main chain of the styrene / acrylic acid ester copolymer tends to break at the ester linkage. This produces odorous low molecular weight substances such as styrene, xylene, isopropylbenzene, butanol, isobutyl acetate, methacrylic acid methyl ester and methacrylic acid butyl ester.

Moreover, most of the conventional toners contain carbon and various organic dyes as coloring materials. In particular, some commercial toners contain only organic dyes as colorants. Typical organic dyes in use include, for example, heavy metal-containing acid dyes and nigrosine base dyes, which tend to release low molecular weight substances such as nitrobenzene, aniline and biphenylamine when the developed toner phase is fixed by flash fixation. There is this.

In other words, when a conventional toner is used in the electrophotographic process in which the shaped toner image is settled by flash fixing, the toner particles produce a gaseous low molecular weight substance to emit an unpleasant odor and harm health.

Thus, an object of the present invention is an electrophotographic process for flash-fixing a developed toner phase developed with a specific toner, that is, an electrophotographic process for flash-fixing a very small amount of a gaseous low molecular weight compound which gives off an unpleasant smell to the developed toner phase. To provide a way.

In one aspect of the present invention, in the electrophotographic process of developing an electrostatic latent image as toner particles and fixing the developed image by irradiation with high energy ultraviolet or visible light, the toner particles are suitable for fixing by flash fixing. The particles are composed of 0.6 to 8% by weight of carbon, 0 to 5% by weight of dye as a colorant, 62 to 99.4% by weight of binder resin, and 95% of binder resin. More than% is a bisphenol A / epichlorohydrin type epoxy resin having a melting point of 60 to 160 ° C., an epoxy equivalent of about 450 to about 5,500, and a weight average molecular weight of about 900 to about 8,250. An improved electrophotographic processing method is provided that uses fine toner particles.

The present invention is provided below.

The total weight or at least 95% of the amount of the binder resin contained in the toner fine particles is composed of the specific bisphenol A / epichlorohydrin type epoxy resin. One or more resin binders are used in combination with bisphenol A / epichlorohydrin type epoxy resins for the purpose of depositing antistatic properties. The amount of such resin binder should not exceed 5% of the total weight of the resin binder.

The specific bisphenol A / epichlorohydrin type epoxy resin has a very stable molecular structure against high energy ultraviolet exposure, and thus, even if ultraviolet light is irradiated to the epoxy resin, unpleasant and harmful gases are not emitted.

This bisphenol A / epichlorohydrin type epoxy resin should not be blocked at room temperature and should also easily and rapidly melt when exposed to flash light of appropriate intensity.

For these requirements, the bisphenol A / epichlorohydrin type epoxy resin has a melting point of 60 to 160 ° C, more preferably 80 to 120 ° C, an epoxy equivalent of 450 to 5,500 and an average molecular weight of about 900 to about 8,250. Has As a bisphenol A / epichlorohydrin type epoxy resin, Epikote (brand name) 1001, 1004, 1007, 1009 by Cell Chemical Co., Ltd. is made, for example, from Ciba_Geigy Co. Araldite (trade name) 6071, 7071, 7072, 6084, 7097, 6097, 6099, DER (trade name) 660, 661, 662, 664, 667, 668, 669 and Dainipek ink company And commercial epoxy resins such as Epiklon (trade name) 1050, 3050, 4050, 7050. The bisphenol A / epichlorohydrin type epoxy resin can be varied in the range of 62 to 99.4% by weight based on the weight of the toner particles.

The smallest possible fine carbon powder occupies the core of each toner particle. This fine carbon powder should be present in an amount sufficient to dissolve the binder resin when the toner particles are exposed to the flash light. For this purpose, the amount of fine carbon powder should be at least 0.6% by weight, preferably at least 4% by weight, based on the weight of the toner particles. The maximum allowable capacity of the fine carbon powder is 8% by weight, preferably 6% by weight, based on the weight of the toner particles.

When the fine carbon powder exceeds 8% by weight, the melter's melt fluidity becomes insufficient and thus requires exposure to a higher fixing temperature, ie stronger flash light.

A small amount of dye is mixed with the toner fine particles for the purpose of adjusting the color tone of the toner and to prevent irregular reflection of the flash light on the surface of the toner particles.

As such dyes, nigrosine base dyes are more preferably used. However, nigrosine base dyes and some other organic dyes tend to decompose when exposed to flash light as previously described. Therefore, this dye amount should not exceed approximately 5% by weight based on the weight of the toner particles. Perhaps the preferred amount of dye is generally in the range of 3% by weight.

When a small amount of montanic acid ester wax is mixed with the toner fine particles, it has been found that the radiation quality is improved. In other words, even if a lot of radiation is made repeatedly, the image luminance is not greatly reduced, and the backside of each radiation can be crushed and the incomplete transfer on the toner can be minimized. This improvement in radiation quality is presumed to be due to the fact that the montanic acid ester wax provides blocking resistance and lubricity to the toner particles.

As used herein, "Montanic acid ester wax" means montanic acid wax, which is composed of C20 to C30 fatty acids such as montanic acid (monobasic straight saturated fatty acid having 28 carbon atoms). Ester.

When the amount of this montanic acid ester wax is too small of the toner particles, toner particles having the desired blocking resistance and lubricity cannot be obtained. On the contrary, if the amount of the montanic acid ester wax is too high, undesirably only wax is formed on the surface of the carrier and the photosensitive member, and a fog occurs on the copy and the toner image is not transferred intact, resulting in a change in charge and a latent image obtained. This is not satisfactory.

Moreover, most waxes other than montanic acid ester waxes result in toner particles having poor blocking resistance and fixability.

If desired, small amounts of suitable additives may be added to the toner fine particles used in the present invention, for example charging agents such as polyphenylene-polyamine (trade name "AFP-B" manufactured by Orient Chemical Industries, Inc.) based on the weight of the toner particles. It may be used in an amount not exceeding approximately 3% by weight.

The toner fine particles used in the present invention can be produced by a conventional method of classifying each component by mixing and grinding each other into particles of a desired size.

Each process of the electrophotographic processing method of the present invention using the toner fine particles as a developing material will be by a conventional method. The latent image is developed with the toner fine particles of the present invention, and the developed toner phase is fixed by exposing the toner phase to high energy ultraviolet rays or visible light. For example, the developed toner image may be exposed to flash light emitted from a xenon flash lamp of 300 to 1500 j / pulse.

When the present invention is described below as examples and comparative examples according to the present invention, each part is represented by weight.

Example 1

92 parts of bisphenol A / epichlorohydrin-type epoxy resins (trade name "Epiclon 4050" manufactured by Dainippon Ink, Inc.) having an epoxy equivalent weight of about 950, a weight average molecular weight of about 2,000, and a melting point of about 100 캜, and an average particle diameter of 24 microns. 5 parts of fine carbon black powder (brand name "Black-Pearls L" manufactured by Kabot Corporation) and 2 parts of nigrozin base dye ("Nigrozin black EX" made by Orient Chemical Industries, Inc.) One part of di- (2-hydroxyepoxyethyl) octadecylamine was mixed together by using a kneader to be kept at a temperature of 100 ° C.

The kneaded material was crushed by a spray mill and mixed together by using a wind classifier.

Using the toner particles thus obtained, a correspondence copy was made by a laser printer operating at a printing speed of 16 cm / min. The printer was equipped with a xenon flash lamp (manufactured by Ushio Electric Co., Ltd.), and the developed toner image was flash-fixed at 300j / pulse. The printer's flash fixing chamber was ventilated at a rate of 1 l / min, and gaseous organic matter in the released air was analyzed as follows. This gaseous organic material was collected by porous plymer beads Tenax GC (for use as a fill of gas chromatography) and separated by using a gas chromatography mass spectrometer. This separated gaseous organic material was quantified by an ion multiplier. Toluene below 10 ppb was improved by analysis.

Comparative Example 1

In a similar process to that used in Example 1, the toner fine particles were subjected to 46 parts of bisphenol A / epichlorohydrin type epoxy resin as used in Example 1, and a styrene / acrylic acid having a weight average molecular weight of approximately 60,000 and a melting point of 140 캜. 46 parts of n-butyl copolymer (trade name "Hymer SBM" -600, manufactured by Sanyo Chemical Co., Ltd.) and 6 parts of nugget black EX are prepared. Made. When the developed toner image was flash settled, the unpleasant smell disappeared. 20-30 ppb of styrene, trichloroethylene, xylene, isobutyl acetate, butyl acrylate, and methyl acrylate was detected by analysis of the gaseous organic matter contained.

Example 2

According to a procedure similar to that used in Example 1, the toner fine particles were bisphenone A / epichlorohydrin type epoxy resin (cell) having an epoxy equivalent weight of about 950, a weight average molecular weight of about 1,400, and a melting point of about 100 캜. 93 parts of the trademark "Epikote 1004" manufactured by Chemical Co., Ltd., 5 parts of the same carbon black powder as used in Example 1, and 2 parts of nigrosine black EX were used. Using the prepared toner, a new copy was made in a manner similar to that performed in Example 1. The flash settled on the developed toner released an unpleasant smell only negligible. A chart of the gas chromatograph mass spectrometer of the generated gaseous organic compound is shown in FIG. 1, where the peaks a, d, e and g represent air, methyl isobutyl ketone, toluene and xylene, respectively.

Example 3

According to a procedure similar to that used in Example 1, the toner fine particles were subjected to 83 parts of bisphenol A / epichlorohydrin type epoxy resin, 5 parts of carbon black powder, 2 parts of nigoro acid black EX, and Montan acid ester wax (Hoechst A. The ester wax E and Ewax made by G Company were made into 10 parts with a dropping point of 79-85, an acid value of 15-20, a saponification value of 130-160, and a density of 1.01-1.03 g / cm ³ ). Epoxy resins, carbon black powder and nigrosine black EX were the same as those used in Example 2.

Using the toner fine particles thus prepared, a correspondence copy was made by a method similar to that performed in Example 1. When flashing the developed toner phase, an unpleasant odor was emitted to a negligible level. The gaseous organic compounds detected were similar to those mentioned in Example 1. Even when 30,000 copies were made, the printed image was clear and there was no crushing on the back side. On the other hand, when 30,000 sheets of copying were carried out using the toner particles of Example 2, the print image became blurred and crushed on the back, and incomplete image transfer was observed.

Comparative Example 2

Following a similar procedure as in Example 3, styrene / methacrylic acid n-butyl copolymer (trade name "Hymer SBM" -73 manufactured by Sanyo Chemical Co., Ltd.) was used as a bonding resin instead of bisphenol A / epichlorohydrin type epoxy resin. Toner was prepared. All conditions were substantially the same.

Using the toner thus prepared, a copy of the correspondence was made in a manner similar to that performed in Example 3. An unpleasant odor was emitted when the developed toner was flash-set onto the image. A chart of a gas chromatographic mass spectrometer of a gaseous organic compound is shown in FIG. 2, with the peaks representing the following low molecular weight compounds. Ie a is air, b is n-butanol, c is methyl methacrylate and trichloroethylene, d is methyl isobutyl ketone, e is toluene, f isobutyl acetate, g is xylene, h is styrene, i Is a methylation of α-methylstyrene and butyl methacrylate, and j is an unidentified acrylic acid compound.

The arrow in FIG. 2 means that the low molecular weight compound corresponding to the peak indicated by the arrow is the source of the unpleasant odor.

Claims (1)

In the electrophotographic method of developing an electro latent image with toner fine particles and fixing the developed image by irradiation with high energy ultraviolet rays or visible light, 0.6 to 8 wt% of carbon and 0 to 5 wt% based on the toner weight 62 to 99.4, wherein the dye is a colorant and a bisphenol A / epichlorohydrin type epoxy resin having a melting point of 60 to 160 ° C, an epoxy equivalent of about 450 to 5,500 and a weight average molecular weight of about 900 to about 8,250. An electrophotographic processing method characterized in that an electro latent image is fixed by adding 1 to about 20 wt% of Montan acid ester wax to a toner made of a wt% binder resin.

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