JP2769856B2 - Image forming method - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to an electrophotographic toner, and more particularly, to an image forming method in which the durability of a fixing roller is significantly improved.

[Prior Art] Conventionally, many electrophotographic methods have been known as described in US Pat. No. 2,297,691 and JP-B-42-23910 and JP-B-43-24748. Generally, a photoconductive substance is used, and then the latent image is developed using toner, and if necessary, a toner image is transferred to a transfer material such as paper. Is what you get.

Also, various development methods for visualizing an electric latent image using toner have been known.

For example, the magnetic brush method described in U.S. Pat. No. 2,874,063, the cascade development method described in U.S. Pat. No. 2,815,552, and the jumping-brush development method and liquid development method described in JP-A-62-63970. Many other developing methods are known. As a toner used in such a developing method or the like, conventionally, a fine powder in which a dye or a pigment is dispersed in a natural or synthetic resin is used. Further, it is known to use a finely developed powder to which a third substance is added for various purposes.

In recent years, the development from white-black copiers to full-color copiers has been rapidly progressing, and two-color color transfer machines and digitized full-color copiers have been launched in the market.

Color image formation by full-color electrophotography generally reproduces all colors using three color toners of three primary colors, yellow, magenta, and cyan, or four colors including black.

The general method is to first form an electrostatic latent image on a photoconductive layer by passing light from a document through a color separation light transmitting filter having a complementary color relationship with the color of the toner. Next, the toner is held on a support through development and transfer steps. Next, the above-described steps are sequentially performed a plurality of times, and while the registration is being performed, the toner is superimposed on the same support, and the final full-color image is obtained by performing the fixing only once.

In such a color electrophotography method in which development is performed a plurality of times and several types of toner layers having different colors are superposed on the same support as a fixing step, the fixing characteristics that the color toner should have are extremely important. Element.

That is, the fixed color toner is required to suppress irregular reflection due to toner particles as much as possible and have appropriate gloss and gloss.

Further, the color toner must be transparent and have a wide color reproducibility so as not to hinder the toner layers of different color tones under the toner layer.

As color toners that can satisfy these requirements, the present applicants have disclosed a novel color binder resin and a coloring agent in JP-A-50-62442, JP-A-51-144625, and JP-A-59-57256. A combination of agents has been disclosed.

The color toners described above have considerable sharp melt properties, change the toner shape to a state close to complete melting at the time of fixing, and obtain favorable glossiness and color reproducibility. However, the offset resistance is not yet sufficient.

The fixing roller is roughly classified into a silicone rubber roller and a Teflon-coated roller.Especially, when a silicone rubber roller is used as the fixing roller, the silicon rubber surface is essentially separated by repeated use regardless of the application of a releasing oil. Due to the reduction in moldability, high-temperature offset is likely to occur. In the silicon rubber roller, a certain degree of mold releasability can be maintained at the beginning of use due to the smoothness and cleanliness of the roller surface. However, when a color copy having a large image area such as a color image and a toner holding amount on a support is remarkably increased as compared with a black and white copy image, the releasability of the roller gradually decreases. The speed at which the releasability deteriorates reaches several times that of black-and-white copying. As a result, a so-called high-temperature offset occurs, in which a toner film or a granular attachment is formed on the roller surface after only several thousand to tens of thousands of sheets, or the toner upper layer portion of the image surface is peeled off when passing through the heat roller. .

On the other hand, a Teflon-coated roller generally has good durability, but easily spreads the toner by pressure, and therefore has a disadvantage that the resolution is reduced in a copy image and the background stain is conspicuous. To improve these drawbacks, rubber coated with a 300-100 μm PFA (perfluoroalkoxy resin) tube (Japanese Patent Publication No. 58-43740)
Publication). When these rollers are used, the reduction in the resolving power of the copied image due to the toner expansion is improved.

However, in general, when a Teflon-coated roller is used as a fixing roller, for example, a roller in which an outer peripheral surface of a cored bar is covered with a relatively thick rubber or other elastic material layer is used as a pressure roller.

In this case, on the contrary to the direction shown in FIG. 1, the direction from which the sheet is discharged from the fixing roller after the fixing is performed from the vertical direction of the line connecting the centers of the fixing roller and the pressure roller is toward the fixing roller. I have.

For this reason, the fixed image is dragged by the fixing roller even after passing through the nip portion where the fixing roller and the pressure roller are in contact with each other, causing a so-called “swirling” phenomenon, thereby causing an offset. In order to prevent this, there is a method to attach a separation paper for paper discharge.However, this separation paper is in contact with the fixing roller, and therefore, it is particularly scratched and leaves traces on the image surface. In full-color copying such as a photograph having a large image area, the image quality is significantly reduced.

Various measures have been attempted for fixing devices and toners to solve or alleviate this problem, but they have not been sufficiently solved.

As the fixing device, a material having excellent surface releasability is used.
Alternatively, a device such as applying oil to the roller is used.
Most of the heat roller fixing devices of currently commercialized copiers apply oil in some form. However, the application of a large amount of oil to enhance the releasability causes undesired problems such as oil contamination of the sheet and an increase in cost.

Also, as a toner, a method of adding a low molecular weight polyethylene wax that sufficiently melts when heated to increase the releasability has been used, but it is effective in preventing offset, but a large amount is included in color toner OHP. Adverse effects such as impairing the transparency of the image, instability of the charging characteristics, and deterioration of the durability are also recognized, and it is difficult to say that the image is satisfactory.

In addition, as a problem peculiar to color copying, in particular, the color balance of at least three color toners, and preferably four colors, must be in harmony. Therefore, the respective colors are balanced in the fixing characteristics and color reproducibility. Must be something.

In principle, if there are three primary colors, yellow, magenta, and cyan, almost all colors should be able to be reproduced by the subtractive color mixing method, and therefore, full-color copying machines currently on the market Has a configuration in which three primary color toners are used in an overlapping manner. This should ideally allow any color to achieve any density range,
In reality, there are still points to be improved, such as the spectral reflection characteristics of the toner, the color mixing at the time of superimposing and fixing the toner, and the decrease in the saturation.

When black is obtained by superimposing three colors, three times more toner layers are formed on the transfer paper than in the case of a single color, as described above, and further, it is necessary to further reduce the offset resistance.

However, the present inventors have intensively studied to complement the improvement of the color toner and the improvement of the fixing device, and have found the following.

That is, when a pigment-based colorant is used for a color toner, contamination of the fixing roller is significantly reduced as compared with the case where a dye-based colorant is used. Therefore, the durability of the fixing roller is also improved. However, when only a pigment-based colorant is used, particularly for a magenta toner, the obtained image has poor chroma and poor color reproducibility.

Regarding magenta toner and fixing property, the applicant of the present invention
-15555-7, the use of a rhodamine-based basic dye alone or in combination with a pigment makes it possible to remarkably improve the dyeing offset on the silicone rubber fixing roller as compared with the rhodamine-based oil-soluble dye. showed that.

However, as a result of detailed studies by the present inventors, as for the use of a rhodamine-based basic dye alone, since it forms a salt that is easily dissociated in water, it is inferior in charging characteristics and affected by environment such as temperature and humidity. I knew that I would be greatly affected.

Further, the pigment / dye combination system can increase the saturation, but has a drawback due to the combination system.

Since the affinity between the dye and the pigment used is poor, they mutually repel each other in the binder resin during the dispersion step, making it difficult to make the color tone uniform. In addition, since the compatibility of each dye / pigment with the binder resin is not uniform, the two are not simultaneously in the same dispersion state, and the pigment is poorly dispersed or the dispersion time is too long. As a result, separation of the dye tends to occur. If the colorant unevenly distributed as described above is used as the toner, the charging characteristics of the electrophotography are inferior, and the cause of fogging, contamination due to scattering of the toner in the machine, and the translucency of the OHP image are also reduced. I understood that.

Also, in the examples of JP-A-62-15555-7, a phenol resin is used as a charge control agent, and a combined use of this rhodamine-based basic dye and a pigment is used as a colorant, and the dyeing offset to a silicone rubber roller is reduced. It did not occur at all.

However, as described above, the dispersion of the colorant is poor,
A toner having poor charging characteristics has a property of easily aggregating. In particular, a phenomenon called "carrier pulling" occurs in which the toner adheres to the periphery of the carrier during development, and the carrier is developed together with the toner.

Therefore, the present inventors conducted intensive studies, and in a pigment-dye combination system, by using a dye treated with a resin different from the binder resin, migration of the dye was prevented,
A color toner having good color reproducibility and good fixing characteristics has been invented.

 This is presumed to be due to the following reasons.

A method in which a dye previously treated with a resin different from the binder resin is kneaded with a pigment and a binder resin to obtain a toner, and a method in which a pigment, a dye, a resin for dye treatment, and a binder resin are kneaded at a time to form a toner Is obtained, the dispersion state of the colorant is completely different. Although this is not clear, it is considered that the action between the dye processing resin and the dye is changed by the presence of the pigment or the binder resin.

As a result, even if the pigment-dye combination system and the phenol resin are contained as described above, those having poor dispersion may cause a phenomenon such as "carrier pulling", and when the carrier passes through the fixing machine, In particular, in the case of a silicon rubber roller, the carrier is embedded in the rubber, and as a result, the life of the fixing roller is shortened.

Therefore, the fact that the dye is treated in advance with a resin different from the binder resin is not the same as the case where the toner is used.

Further, in the fixing device including the fixing roller and the pressure roller, when the white paper is passed, the paper discharge direction is set to be higher than the vertical direction of the line connecting the center of the fixing roller and the pressure roller. It has been found that by setting it on the roller side, it is possible to prevent "fixation" of the fixed image surface by the fixing roller.

By using the fixing device and the color toner, it was found that a copied image having good color reproducibility was obtained, and the durability of the fixing roller could be drastically increased.

[Problems to be Solved by the Invention] In view of the above-mentioned problems, an object of the present invention is to provide an image forming method using a color toner exhibiting good fixability and color mixing in full-color copying.

Another object is to provide an image forming method using a color toner having a sufficient triboelectric charging property.

It is another object of the present invention to provide an image forming method using a highly glossy color toner which significantly improves image quality.

It is another object of the present invention to provide an image forming method using a color toner which is hard to cause carrier spent even when repeatedly copied and has excellent durability.

Another purpose is to prevent hot offset sufficiently,
An object of the present invention is to provide an image forming method having a wide fixable temperature range.

It is another object of the present invention to provide an image forming method in which the offset resistance is maintained even after repeated fixing.

[Means and Actions for Solving the Problems] A feature of the present invention is that a multicolor electrophotographic method is performed using a magenta toner, a cyan toner, and a yellow toner, or a developer having the three-color toner and a black toner. A magenta toner is a toner having resin particles containing a magenta dye treated with a resin different from the magenta coloring pigment and the binder resin, and a flow improver. The cyan toner is a toner having resin particles containing a color pigment for copper cyanide and a flow improver, and the yellow toner is a toner having resin particles containing a color pigment for yellow and a flow improver, The black toner includes at least two pigments selected from a magenta color pigment, a cyan color pigment, and a yellow color pigment.
A toner having resin particles containing at least one kind of pigment or carbon black and a flow improver, transferring the full-color toner image to a transfer paper, and a fixing roller and a pressure roller having a rubber-like elastic material on the core metal. (I) the hardness of the pressure roller so that the paper discharge direction is closer to the pressure roller than the direction perpendicular to the line connecting the center of the fixing roller and the pressure roller. Higher than the fixing roller hardness, or
(Ii) An image forming method for fixing a full-color toner image on transfer paper by using a fixing device in which the diameter of the fixing roller is larger than the diameter of the pressure roller.

Examples of the binder resin used in the present invention include styrene resin, polyester, polyvinyl chloride, polyethylene, polypropylene, polyurethane, polyamide, silicone resin, epoxy resin, polyvinyl butyral, phenol resin, xylene resin, chlorinated paraffin, and paraffin wax. , Etc. are used alone or in combination.

Preferred binder resins include styrene resins and polyester resins.

As the styrene-based resin, for example, styrene, o-methylstyrene, m-methylstyrene, p-methylstyrene, p-phenylstyrene, p-
Ethylstyrene, 2,4-dimethylstyrene, pn-butylstyrene, p-tert-butylstyrene, pn-hexylstyrene, pn-octylstyrene, pn-
Nonylstyrene, pn-decylstyrene, pn-dodecylstyrene, p-methoxystyrene, p-chlorostyrene, 3,4-dichlorostyrene, m-nitrostyrene, o-nitrostyrene, p-nitrostyrene, etc. Styrene derivatives of ethylene; ethylene and unsaturated monoolefins such as ethylene, propylene, butylene and isobutylene; unsaturated diolefins such as butadiene and isoprene; vinyl halides such as vinyl chloride, vinylidene chloride, vinyl bromide and vinyl fluoride Vinyl esters such as vinyl acetate, vinyl propionate and vinyl benzoate; methyl methacrylate, ethyl methacrylate, propyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, n-octyl methacrylate, dodecyl methacrylate; Methacrylic acid-2-ethyl Α-methylene aliphatic monocarboxylic esters such as hexyl, stearyl methacrylate and phenyl methacrylate; methyl acrylate, ethyl acrylate, n-butyl acrylate, isobutyl acrylate, propyl acrylate, n-octyl acrylate, Acrylic esters such as dodecyl acrylate, 2-ethylhexyl acrylate, stearyl acrylate, 2-chloroethyl acrylate and phenyl acrylate; maleic acid, maleic acid half ester, vinyl methyl ether, vinyl ethyl ether, vinyl isobutyl ether, etc. Vinyl ethers such as vinyl methyl ketone, vinyl hexyl ketone, and methyl isopropenyl ketone; N-vinyl pyrrole, N-vinyl carbazole, N-vinyl indole, N-vinyl pyrrol N- vinyl compounds such emissions; vinyl naphthalenes; acrylonitrile, methacrylonitrile, acrylic acid or methacrylic acid derivatives such as acrylamide; those obtained by polymerizing using acrolein, etc. one or more is used.

Styrene resins particularly preferred for the practice of the present invention include copolymers of styrene and acrylic esters or α-methylene aliphatic monocarboxylic esters.

This is because, when the styrene-based resin obtained from these monomers is used as a binder resin for a full-color toner, it has good color mixing properties and excellent offset resistance.

Furthermore, in order to obtain a styrenic resin with excellent fixability,
The amount of styrene in the resin is 50 to 95 mol%, preferably 60 to 90 m
ol% is desirable.

 The composition of the polyester resin is as follows.

45 to 55 mol% of all components of the polyester resin is an alcohol component, and 55 to 45 mol% is an acid component.

As the alcohol component, ethylene glycol, propylene glycol, 1,3-butanediol, 1,4-butanediol, 2,3-butanediol, diethylene glycol, triethylene glycol, 1,5-pentanediol, 1,6-hexane Diol, neopentyl glycol, 2-ethyl-1,3-hexanediol, hydrogenated bisphenol A, and a bisphenol derivative represented by the formula (A); (Wherein R is an ethylene or propylene group, x and y are each an integer of 1 or more, and the average value of x + y is 2 to 10.) Diols represented by the formula (B); Examples include polyhydric alcohols such as glycerin, sorbit, and sorbitan.

Examples of the divalent carboxylic acid containing 50 mol% or more of the total acid component include phthalic acid, terephthalic acid, isophthalic acid,
Benzenedicarboxylic acids such as phthalic anhydride or anhydrides thereof; alkyldicarboxylic acids such as succinic acid, adipic acid, sebacic acid, azelaic acid or anhydrides thereof, and further, succinic acid substituted with an alkyl group having 6 to 18 carbon atoms Or an anhydride thereof; fumaric acid, maleic acid, citraconic acid, an unsaturated dicarboxylic acid such as itaconic acid or an anhydride thereof, and the like, and examples of the trivalent or higher carboxylic acid include trimellitic acid, pyromellitic acid, Benzophenone tetracarboxylic acid and its anhydride are exemplified.

The alcohol component of the polyester resin particularly preferred in the practice of the present invention is a bisphenol derivative represented by the formula (A), and the acid component is phthalic acid, terephthalic acid, isophthalic acid or anhydride thereof; succinic acid, n
-Dodecenyl succinic acid or anhydride thereof, fumaric acid, maleic acid, dicarboxylic acids such as maleic anhydride, and trimellitic acid or tricarboxylic acids of anhydride thereof.

This is because the polyester resins obtained with these acids and alcohols show sharp melting properties, have good color mixing properties as toners for full color and heat roller fixing, and have excellent offset resistance.

Furthermore, the glass transition temperature of the polyester resin obtained here is 50 to 75 ° C., preferably 55 to 65 ° C., and the number average molecular weight n is 1,500 to 7,000, preferably 2,000 to 5,000, and the weight average molecular weight is 6,000 to 150,000. Is 10,000-100,0
Desirably it is 00.

The acid value is 90 or less, preferably 50 or less, the OH value is
It is desirably 50 or less, preferably 30 or less. This is because when the number of terminal groups on the molecular chain increases,
This is because the charging characteristics of the toner greatly depend on the environment.

As the magenta coloring pigment used in the present invention, any pigment can be used in the present invention, but a high-saturation magenta color can be obtained by using it in combination with a dye. The following are examples of pigments that exhibit a black color having a certain color. CI Pigment Red
1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,2
1,22,23,30,31,32,37,38,39,40,41,48,49,50,51,52,53,
54,55,57,58,60,63,64,68,81,83,87,88,89,90,112,114,
122, 123, 163, 202, 26, 207, 209, CI Pigment Violet 19, CI Butt Red 1, 2, 10, 13, 15, 23, 29, 35 and the like.

As the dye for magenta used in the present invention, any dye can be used in the present invention. The following can be mentioned as those which can be used in combination with a pigment to make the color clearer and more close to magenta.

CI Solvent Red 1,3,8,23,24,25,27,30,49,81,8
2,83,84,100,109,121, CI Disperse Red 9, C.
I. Solvent violet 8,13,14,21,27, oil-soluble dyes such as CI Disperse Violet 1, CI Basic Red 1,2,9,12,13,14,15,17,18,22,23, 24,27,29,32,34,3
5,36,37,38,39,40, CI Basic Violet 1,3,7,
And basic dyes such as 10, 14, 15, 21, 25, 26, 27, 28.

As the resin used in the present invention, any resin can be used as long as it is different from the binder resin and can be dispersed in the binder resin. Examples thereof include the following.

Polychlorostyrene, styrene-p-chlorostyrene copolymer, styrene-maleic acid copolymer, styrene-
Fumaric acid copolymer, styrene-methyl acrylate copolymer, styrene-ethyl acrylate copolymer, styrene-
Butyl acrylate copolymer, styrene-octyl acrylate copolymer, styrene-methyl methacrylate copolymer, styrene-ethyl methacrylate copolymer, styrene butyl methacrylate copolymer, styrene-2 ethylhexyl copolymer, Styrene-α-chloromethyl methacrylate copolymer, styrene-vinyl methyl ether copolymer,
Grafted with styrene-based resins such as styrene-vinyl methyl ketone copolymer, styrene-maleic acid-methyl methacrylate terpolymer, polyvinyl chloride, polyvinylidene chloride, polyvinyl acetate, polyethylene, polypropylene and styrene. Modified polyethylene, modified polypropylene, polyester, phenolic resin, epoxy resin,
Polyvinyl butyral resin, chlorinated paraffin and the like.

As a preferred combination among these dyes, pigments and processing resins, the dyes include CI Solvent Red 2
Oil-soluble dyes such as 3,24,25,27,30,49,109 and CI Disperse Violet 1; and as pigments, CI Pigment Red 13,16,18,22,23,38,81,122,123,202,206,20
7,209, CI Butt Red 1,2,29, CI Pigment Violet 19 and the like. In the resin for dye treatment, styrene-methyl acrylate copolymer, styrene-ethyl acrylate copolymer, styrene-butyl acrylate copolymer, styrene-methyl methacrylate copolymer, styrene-ethyl methacrylate copolymer Styrene resins such as styrene-butyl methacrylate copolymer, styrene-maleic acid-methyl methacrylate terpolymer, styrene-maleic acid-2-ethylhexyl terpolymer, polyethylene, polypropylene and styrene, acrylic Modified polyethylene or modified polypropylene grafted with acid, etc.
Examples include polyester, phenol resin, and epoxy resin.

Since the processing resin is dispersed in the toner binder resin, a resin having a melt viscosity equal to or lower than that of the binder resin has good dispersion.

For this purpose, the number average molecular weight n of the processing resin is 300 to 60,
000, preferably 500-50,000, and the weight average molecular weight w
It is desirably 1,000 to 100,000, preferably 1,500 to 90,000. Further, those which are hardly soluble in a solvent for measuring molecular weight such as polyethylene and polypropylene preferably have an average molecular weight of 300 to 70,000, preferably 600 to 50,000 depending on viscosity.

The method of treating the dye or pigment with the resin in the present invention includes: (1) a method of melting and kneading the dye or pigment and the resin with a two-roll mill, a Banbury mixer, a kneader, a three-roll mill, or the like; A method of dissolving in a suitable solvent, dissolving or dispersing the dye or pigment therein, and then removing and drying the solvent.

(3) When a dye or pigment that does not inhibit the polymerization reaction is used, a method of dispersing the dye during polymerization to obtain the dye or pigment is also possible.

Color pigments for cyan used in the present invention include CI Pigment Blue 2,3,15,16,17, CI Bat Blue 6, CI
Acid Blue 45 or a copper phthalocyanine pigment in which 1 to 5 phthalimidomethyl groups are substituted on a phthalocyanine skeleton having a structure represented by the formula (1).

As the coloring pigment for yellow used in the present invention, CI Pigment Yellow 1,2,3,4,5,6,7,10,11,12,13,14,15,1
6, 17, 23, 65, 73, 83, CI bat yellow 1, 3, 20 and the like.

As for the content, for the yellow toner which is sensitive to the transparency of the OHP film, the binder resin 100
12 parts by weight or less based on parts by weight, preferably 0.5 to
7 parts by weight is desirable.

If the amount exceeds 12 parts by weight, the reproducibility of green, red, which is a mixed color of yellow, and human skin color as an image is poor.

For other magenta and cyan color toners, the amount is preferably 15 parts by weight or less, more preferably 0.1 to 9 parts by weight, based on 100 parts by weight of the binder resin.

In particular, for a black toner using two or more colorants in combination, the addition of a total colorant amount of 20 parts by weight or more not only tends to cause spent to the carrier, but also causes a large amount of colorant to be exposed on the toner surface. As a result, the fusing of the toner to the drum and the anxiety of the fixing property also increase. Therefore, the amount of the colorant is preferably 3 to 15 parts by weight based on 100 parts by weight of the binder resin.

A preferable mixing ratio of the colorant for forming the black toner is such that the ratio of the yellow color pigment, the magenta color pigment, and the cyan color pigment is 1: 1.5 to 2.5: 0.5 to 1.5.

The particle size of the carbon black used in the present invention is from 50 to
70 mμ, preferably 50-60 μm. Particle size 50m
The toner containing carbon black of less than μ has a chromaticity that shifts to yellowish, and not only a sharp black color cannot be obtained, but also
Dispersion of the carbon black becomes extremely difficult, and the carbon black exposed on the toner surface becomes non-uniform. Therefore, the adhesion of the fluidity improver is deteriorated, and the fluidity is remarkably reduced, so that a good triboelectric charge amount cannot be obtained. As a result, fogging and toner scattering are caused. The particle size is 70mμ
In the case of exceeding, the blackness of the carbon black is low, and an image showing a vivid black cannot be obtained.

The oil absorption of this carbon black is 50-100cc /
100 g, preferably 60-80 cc / 100 g. If the oil absorption exceeds 100 cc / 100 g, the structure of the carbon black becomes longer, the conductivity increases, and the triboelectric charge of the toner decreases, causing fogging and scattering. If the oil absorption is less than 50 cc / 100 g, a high image density cannot be obtained.

The carbon black contained in the resin is a binder resin
2.1 to 10.0 parts by weight based on 100 parts by weight, preferably 3.0 to 10.0 parts by weight
6.0 parts by weight. If the carbon black content is less than 2.1 parts by weight, a high image density cannot be obtained, and the uniformity of the solid portion decreases. If the carbon black content exceeds 10.0 parts by weight, a sufficient amount of triboelectricity cannot be obtained.

In the measurement of the physical properties of the carbon black, the particle size was measured by directly and selectively counting the particle size in a scanning electron micrograph.

 The method of measuring the oil absorption is described later.

It is also preferable that the toner according to the present invention contains a charge control agent in order to stabilize the negative charge characteristics. At that time, a colorless or light-colored negative charge controlling agent which does not affect the color tone of the toner is preferable. Examples of the negative charge control agent include an organic metal complex such as a metal complex of an alkyl-substituted salicylic acid (for example, a chromium complex or a zinc complex of di-tert-butyl salicylic acid). When the negative charge control agent is blended in the toner, 0.1 to 10 parts by weight based on 100 parts by weight of the binder resin.
It is preferable to add 0.5 parts by weight, preferably 0.5 to 8 parts by weight.

Particle size distribution of classified products of magenta toner, cyan toner, yellow toner, and black toner (colorant-containing resin particles having no flow improver such as silica, aluminum oxide, and titanium oxide described below) obtained using the above-described materials. The volume average particle size is 4.0 to 16.0 μm, preferably 6.0 to 14.0 μm, and 5.0% or less of 5.04 μm in the number average distribution is 50% in terms of copy image quality.
Or less, preferably 40% or less, 20.2 of the volume average distribution.
It is desirable that the value of μm or more is 9% or less, preferably 5% or less.

As the flow improver used in the present invention, any one can be used as long as it can be added to the colorant-containing resin particles to increase the flowability before and after the addition.

For example, fluororesin powder, that is, vinylidene fluoride fine powder, polytetrafluoroethylene fine powder, and the like; or fatty acid metal salt, that is, zinc stearate, calcium stearate, lead stearate, and the like; or metal oxide, that is, aluminum oxide, titanium oxide , Zinc oxide powder, etc .;
Alternatively, there are finely divided silica, that is, wet-process silica, dry-process silica, and treated silica obtained by subjecting the silica to a surface treatment with a silane coupling agent, a titanium coupling agent, silicon oil, or the like.

Preferred flow improvers are fine powders produced by gas phase oxidation of silicon halide compounds, so-called dry silica or fumed silica, which is produced by a conventionally known technique. For example, it utilizes the thermal decomposition oxidation reaction of silicon tetrachloride gas in an oxyhydrogen flame, and the basic reaction formula is as follows.

SiCl ₄ + 2H ₂ + O ₂ → SiO ₂ + 4HCl Preferred examples of the flow improver include aluminum oxide and titanium oxide obtained in the same manner as in the above-mentioned production process.

The particle size is preferably in the range of 0.001 to 2 μm as an average primary particle size, and particularly preferably 0.002 to 2 μm.
It is preferable to use a fine powder within a range of 0.2 μm.

Commercially available fine silica powder produced by vapor phase oxidation of a silicon halide used in the present invention includes, for example, those commercially available under the following trade names.

AEROSIL (Aerosil Japan) 130 200 300 380 TT600 MOX170 MOX 80 COK 84 Ca-O-SiL (CABOT Co.) M-5 MS- 7 MS-75 HS- 5 EH-5 Wacker HDK N 20 (WACKER-CHEMIE GMBH) V15 N20E T30 T40 DC Fine Silica (Dow Corning Co.) Fransol (Fransil) Further, the silica fine powder produced by the gas phase oxidation of the silicon halide is treated with hydrophobic fine silica powder. It is more preferable to use. It is particularly preferable that the treated silica fine powder is obtained by treating the silica fine powder such that the degree of hydrophobicity measured by a methanol titration test shows a value in the range of 30 to 80.

Hydrophobizing is applied by reacting with silica fine powder or chemically treating with an organic silicon compound or the like which physically adsorbs.

As a preferred method, silica fine powder produced by the gas phase oxidation of a silicon halide is treated with an organosilicon compound.

Examples of such organosilicon compounds are hexamethyldisilazane, trimethylsilane, trimethylchlorosilane,
Trimethylethoxysilane, dimethyldichlorosilane,
Methyltrichlorosilane, allyldimethylchlorosilane, allylphenyldichlorosilane, benzyldimethylchlorosilane, bromomethyldimethylchlorosilane, α
-Chloroethyltrichlorosilane, ρ-chloroethyltrichlorosilane, chloromethyldimethylchlorosilane,
Triorganosilyl mercaptan, trimethylsilyl mercaptan, triorganosilyl acrylate, vinyldimethylacetoxysilane, dimethylethoxysilane,
Dimethyldimethoxysilane, diphenyldiethoxysilane, hexamethyldisiloxane, 1,3-divinyltetramethyldisiloxane, 1,3-diphenyltetramethyldisiloxane, and 2 to 12 siloxane units per molecule with terminal positions For example, dimethylpolysiloxane containing a hydroxyl group bonded to one Si unit may be used for each unit. These are used alone or as a mixture of two or more.

The particle size of the treated silica fine powder is 0.003-0.1μm
It is preferable to use those in the range of Commercial products include Taranox-500 (Talco), AEROSIL R-972
(Nippon Aerosil).

The amount added to the colorant-containing resin particles, the resin particles
0.01 to 10 parts by weight, preferably 0.1 to 5 parts by weight per 100 parts by weight
Parts by weight. If it is less than 0.01 part by weight, there is no effect on improving the fluidity, and if it exceeds 10 parts by weight, fogging and bleeding of letters,
Promote in-flight scattering.

The fixing device used in the present invention may be configured such that, when white paper is passed, the paper discharge direction is closer to the pressure roller side than the vertical direction of a line connecting the center of the fixing roller and the pressure roller. It can be used in the invention.

As a method of setting the paper discharge direction to the pressure roller side, for example, the hardness of the pressure roller is made higher than the hardness of the fixing roller. (As a method of increasing the hardness of the pressure roller,
(I) a method of using an elastic body having a hardness higher than that of the fixing roller attached to the cored bar, and (ii) when using the same elastic body as the fixing roller, by making the elastic body layer thickness of the fixing roller thinner. There is a method of making the roller hard. ) The diameter of the fixing roller is made larger than the diameter of the pressure roller.

Further, by mounting the heating device not only on the fixing roller side but also on the pressure roller side, it is possible to significantly reduce the "skew" as compared with the case where the heating device is mounted only on the fixing roller side.

As a fixing device incorporating these methods, for example, as a fixing roller, an elastic body is a silicone rubber-based RTV or LTV.
To reduce rubber swelling due to a single-layer roller or fixing oil, an HTV layer is provided as a lower layer, and an RTV or LTV layer is provided as an upper layer to improve the wetting with the fixing oil. , Its rubber hardness (JIS-A) 30-70 degrees,
(In the case of two layers, when two layers are combined), preferably 35 to
60 degrees, the layer thickness is 0.5-5mm, preferably 1.0-3.5mm
The pressure roller has a hardness of 40 degrees or more, preferably 50 degrees or more, and may be a silicone rubber type, a fluorine rubber type, or a Teflon coat type.

Further, a fixing roller having a two-layer structure such as a silicone rubber-fluoro rubber type, a silicone rubber or a fluoro rubber-Teflon coating type, or a silicone rubber or a fluorine rubber is used for the purpose of improving fixing oil resistance and abrasion resistance. A material having a three-layer structure such as -Teflon coat-silicon rubber may be used, but in this case, it is important that the hardness is within the above-mentioned range.

The diameter of the fixing roller cannot be increased so much because the miniaturization of the copying machine is required. Also, when the diameter of the fixing roller is reduced, the toner is not sufficiently melted due to insufficient nip, so that the color mixing property is deteriorated, and the fixing speed has to be reduced to increase the color mixing property. Therefore, the diameter of the fixing roller and the pressure roller is 40 to 80.
mmφ is appropriate.

 Hereinafter, each measurement method in the present invention will be described.

(1) Measurement of glass transition temperature Tg In the present invention, measurement is performed using a differential thermal analysis measuring device (DSC measuring device), DSC-7 (manufactured by PerkinElmer).

The measurement sample is precisely weighed in an amount of 5 to 20 mg, preferably 10 mg.

Put this in an aluminum pan and use an empty aluminum pan as a reference.
The measurement is performed at normal temperature and normal humidity at a heating rate of 10 ° C./min.

In this heating process, an endothermic peak of a main peak in a temperature range of 40 to 100 ° C. is obtained.

The intersection of the line of the midpoint of the baseline before and after the endothermic peak appears and the differential heat curve is defined as the glass transition temperature Tg in the present invention.

(2) Measurement of molecular weight distribution In the present invention, the molecular weight distribution was measured by high performance liquid chromatography (JASCO TRI ROTAR-VI HPLC system manufactured by JASCO Corporation). The column is Toso TSK gel-2000, manufactured by Toyo Soda Industry Co., Ltd.
-3000, -4000, -5000 were used, and THF was used as a solvent. Detect
or is Shodex RISE-51 manufactured by Showa Denko KK, and the measurement conditions were as follows: Flow rate 1.0 ml / min, column temperature 40 ° C, Inj vol. 75
Performed in μl.

The molecular weight of the sample was calculated from the relationship between the logarithmic value of a calibration curve prepared from several types of monodisperse polystyrene standard samples and the count number, based on the molecular weight distribution of the sample.

As a standard polystyrene sample for preparing a calibration curve, for example, a molecular weight of 6 × 10 ² , 2.1 × 10 ³ , 4 × 10 ³ , 1.75 × 10 ⁴ , 5.15 manufactured by Pressure Chemical Co. or Toyo Soda Industry Co., Ltd.
× 10 ⁴ , 1.1 × 10 ⁵ , 3.9 × 10 ⁵ , 8.6 × 10 ⁵ , 2 × 10 ⁶ , 4.48 × 10 ⁶
It is appropriate to use at least about 10 standard polystyrene samples.

(3) Particle size distribution measurement Coulter counter TA-II type (manufactured by Coulter, Inc.) was used as the measuring device, and an interface (manufactured by Nikkaki) for outputting the number average distribution and volume average distribution, and a CX-1 personal computer (manufactured by Canon) ) Is connected, and a 1% NaCl aqueous solution is prepared as the electrolytic solution using primary sodium chloride.

As a measuring method, a surfactant as a dispersing agent, preferably 0.1 to 5 ml of an alkylbenzene sulfonate is added to the electrolytic aqueous solution of 100 to 150 ml, and a measurement sample of 0.5 to 50 mg is further added.
Add.

The electrolytic solution in which the sample was suspended was subjected to a dispersion treatment for about 1 to 3 minutes using an ultrasonic disperser.
The volume average distribution and the number average distribution are obtained by measuring the particle size distribution of the particles of up to 40 μm.

From the obtained volume average distribution and number average distribution, respective values of the volume average particle diameter, the number average particle diameter, the number average distribution of 5.04 μm or less, and the volume average distribution of 20.2 μm or more are obtained.

(4) Measurement of oil absorption (DBP method) Measurement of oil absorption is performed in accordance with ASTM method D 2414-79.

Operate the faucet of the absorber meter and completely fill DBP (dibutyl phthalate) so that no air bubbles remain in the automatic burette system.

Spring tension 2.68kg / cm Rotor rotation speed 125rpm Scale of limit switch for torque 5 Damper valve 0.150 Dropping speed of DBP 4ml / min After adjusting dropping speed of DBP by actual measurement, dry a certain amount in the absorption meter mixing chamber The sample is put, the buret counter is set to 0 point, and the switch is automatically turned on to start dropping. When the torque reaches the set point (5 in this case), the limit switch is activated and the dripping stops automatically,
The scale (V) of the bullet counter at that time is read, and the oil absorption is calculated by the following equation.

OA: Oil absorption (ml / 100g) V: DBP used up to the end point (limit switch operating point) (ml) W: Weight of dried sample (g) [Examples] Will be described in detail.

Example 1 Polyester resin obtained by condensation of propoxylated bisphenol and fumaric acid (n = 3,800, w = 21,000, T
g = 57 ° C., acid value = 12, OH value = 23) 100 parts by weight of the coloring agent and the charge controlling agent in the amounts prescribed in Table 1 below were used to obtain a full-color toner.

The production method was performed by a master batch method. First,
Melt and knead the polyester resin and the colorant in an amount 6 times the amount of the colorant with a three-roll mill.
It was crushed in the following to obtain a colored resin for a master batch. Next, the polyester resin, the charge control agent, and the colored resin for the master batch were weighed so as to have the above-mentioned predetermined amounts, and were premixed by a Henschel mixer. Thereafter, the mixture is melted and kneaded with a three-roll mill, and after cooling, about 1 to 2 mm using a hammer mill.
The mixture was coarsely pulverized to an appropriate degree, and then finely pulverized to a particle size of 30 μm or less by a pulverizer using an air jet method. Further, the obtained finely pulverized product was classified and adjusted to the particle size distribution shown in Table 2.

As a flow improver for each of these classified products, 0.5 parts by weight of silica fine powder treated with hexamethyldisilazane was added to 100 parts by weight of each classified product, 0.2 parts by weight of aluminum oxide fine powder,
Was added externally to obtain a full-color toner.

As a carrier, styrene-2-ethylhexyl acrylate-methyl methacrylate (copolymer weight ratio 50: 20: 3)
Using a Cu-Zn-Fe-based ferrite carrier coated with 0.5% by weight of (0) (average particle size 42 μm; 250 mesh pass, 400 mesh on 82% by weight), a developer was prepared so that the toner concentration of each color was 5% by weight. .

Using these developers and toners, an image output test was performed with a full-color copying machine CLC-1 manufactured by Canon. The fixing roller is a three-layer RTV / Teflon coat (tetrafluoroethylene resin) / HTV with a rubber layer thickness of 3.0 mm, a hardness of 45 degrees, and a fixing roller diameter of 40 mmφ. Rubber-based roller, hardness 55 degrees, layer thickness 1mm, diameter
The thing of 40mmφ was used. The heating device was also attached to the pressure roller side. In the blank paper passing test, the paper discharge direction was toward the pressure roller.

As a result of the image formation test, there was no offset to the fixing roller even after printing for 20,000 sheets in the full-color mode, and a full-color image faithfully reproducing the original color chart without fog was obtained.

Example 2 Styrene-based resin obtained by polymerizing styrene and n-butyl acrylate (n = 16,000, w = 49,000, Tg = 59)
C.) 100 parts by weight of the coloring agent and the charge control agent in the amounts prescribed in Table 3 below were used, and the same procedure as in Example 1 was carried out to obtain a classified full-color toner having a particle size distribution shown in Table 4. .

0.5 parts by weight of silica fine powder treated with hexamethyldisilazane as a flow improver was externally added to 100 parts by weight of the classified toner to obtain a full-color toner.

The carrier is vinylidene fluoride-tetrafluoroethylene copolymer (copolymerization weight ratio 8: 2) and styrene-
Cu-Zn-Fe ferrite carrier coated with 0.6% by weight of acrylic 2-ethylhexyl-methyl methacrylate (copolymerization ratio: 45:20:35) at a weight ratio of 50:50 (average particle size)
Using a 48 μm, 250 mesh pass, 400 mesh on 91.0 wt%), a developer was prepared such that the toner concentration of each color became 9 wt%.

Using these developers and toners, a full-color copier CLC-1 made by Canon was manufactured using the same fixing device as in Example 1.
An image output test was performed.

As a result, there was no offset to the fixing roller even after printing for 20 000 sheets in the full-color mode, and a full-color image faithfully reproducing the original color chart without fog was obtained.

Example 3 The fixing roller has a two-layer structure of silicon rubber (RTV) -silicon rubber (HTV), a layer thickness of 2.0 mm, a hardness of 50 degrees,
A roller with a roller diameter of 60 mmφ is used. The pressure roller has a two-layer structure of silicon rubber (HTV) -Teflon coat (tetrafluoroethylene resin), and has a layer thickness of 1.0 mm and a hardness of 60 mm.
A roller with a roller diameter of 60 mmφ was used. The heating device was also mounted on the pressure roller side. In a blank paper passing test using this fixing device, the paper discharging direction was toward the pressure roller. This fixing device is a Canon full-color copier CLC-
1 and an image output test was performed using the toner and the developer of Example 1.

As a result, a full-color image faithfully reproducing the original color chart without fogging and having no offset to the fixing roller even after printing 15,000 sheets in the full-color mode was obtained.

Example 4 The fixing roller was a two-layer RTV / HTV silicone rubber having a layer thickness of 1.5 mm, a hardness of 55 degrees, and a roller diameter of 80 mmφ. The pressure roller was a silicone rubber (HTV) -fluororubber rubber. A layered structure having a layer thickness of 1.0 mm, a hardness of 55 degrees and a roller diameter of 60 mm was used. The heating device was also attached to the pressure roller side. In a blank paper passing test using this fixing device, the paper discharging direction was toward the pressure roller.
This fixing device was attached to a Canon full-color copying machine CLC-1, and an image output test was performed using the toner and developer of Example 2.

As a result, there was no offset to the fixing roller even after printing for 35,000 sheets in the full-color mode, and a full-color image faithfully reproducing the original color chart without fog was obtained.

Comparative Example 1 A classified product of magenta toner was prepared in the same manner as in Example 1, except that 1.5 parts by weight of CI Solvent Red 25 was used as a colorant for magenta toner.
91μm, number average distribution 5.04μm or less 33.1%, volume average distribution
20.2 μm or more and 0.0%). The other colors used in Example 1 were used.

Thereafter, an image-drawing test was performed in the same manner as in Example 1.

As a result, it was found that only magenta toner was offset to the fixing roller after 6,000 printings in the full color mode.

Comparative Example 2 A fixing roller having a two-layer fluororubber-teflon coat (tetrafluoroethylene-fluoroalkoxyethylene copolymer resin) having a hardness of 78 degrees, a layer thickness of 0.5 mm and a roller diameter of 60 mm was used. As the pressure roller, a single layer of silicon rubber (HTV) having a hardness of 50 degrees, a layer thickness of 5.0 mm, and a roller diameter of 60 mmφ was used. The heating device was attached only to the fixing roller side. In a blank paper passing test using this fixing device, the paper discharging direction was toward the fixing roller.

The fixing device was attached to a full-color copying machine CLC-1 manufactured by Canon Inc., and an image output test was performed using the toner and the developer of Example 1.

As a result, a so-called "offset jam", in which the image was wound around the fixing roller from the first image output, occurred, and the printing durability test could not be performed.

[Effects of the Invention] As described above, according to the image forming method of the present invention,
Even after an image formation test, for example, after printing for 35,000 sheets, no offset occurs and a full-color image faithfully reproducing the original color chart without fog can be obtained.

In addition, the toner transportability in the copying machine is good, a stable image density can be obtained, and a good image with little fog and toner scattering can be obtained.

[Brief description of the drawings]

FIG. 1 is a view illustrating a state in which a sheet is discharged from a direction perpendicular to a line connecting a center line of a fixing roller and a pressure roller to a pressure roller side in order to explain a feature of the present invention. It is.

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-63-301960 (JP, A) JP-A-63-313174 (JP, A) JP-A-64-9466 (JP, A) JP-A-54-946 5733 (JP, A) JP-A-63-125950 (JP, A) JP-A-60-56066 (JP, U) JP-A-61-42555 (JP, U) JP-A-63-148962 (JP, U) (58) Field surveyed (Int.Cl. ⁶ , DB name) G03G 9/09 G03G 9/08 G03G 15/01 G03G 15/20

Claims (1)

(57) [Claims] 1. A full-color toner image is formed by a multicolor electrophotographic method using a developer having three colors of magenta toner, cyan toner and yellow toner, or a developer having the three-color toner and black toner. Are resin particles containing a magenta dye treated with a resin different from the magenta color pigment and the binder resin, and a toner having a flow improver. The cyan toner is a resin particle containing a cyan color pigment. The yellow toner is a resin particle containing a yellow color pigment and a toner having a flow improver, and the black toner is a magenta color pigment, a cyan color pigment and a yellow toner. Particles containing at least two or more pigments selected from color pigments for use or carbon black and flow trends A transfer roller for transferring the full-color toner image to a transfer paper, wherein the fixing roller and the pressure roller are a heat roller fixing device having a rubber-like elastic layer on a cored bar; The paper direction is
(I) The hardness of the pressure roller is higher than the hardness of the fixing roller so that the pressure roller is closer to the pressure roller than the vertical direction of the line connecting the center of the fixing roller and the pressure roller, or (ii)
An image forming method, comprising: fixing a full-color toner image on transfer paper using a fixing device in which the diameter of a fixing roller is larger than the diameter of a pressure roller.