JP2736987B2 - Color toner for color image formation - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a mono-color copying machine to a full-color copying machine for developing an electrostatic image in electrophotography, electrostatic recording, electrostatic printing and the like. And a toner resin.

[Prior Art] Conventionally, many electrophotographic methods have been known as described in U.S. Pat. No. 2,297,691, Japanese Patent Publication No. 42-23910, and Japanese Patent Publication No. 43-24748. However, in general, a photoconductive substance is used to form an electric latent image on a photoreceptor by various means, and then the latent image is developed using toner, and if necessary, a transfer material such as paper is used. After the transfer of the toner image to the toner image, the toner image is fixed by heating, pressure or solvent vapor to obtain a copy.

Various methods and apparatuses have been developed for the final step of fixing the toner image on a sheet such as paper. Currently, the most common method is a pressure heating method using a heating roller.

In the pressure heating method using a heating roller, fixing is performed by allowing the toner image surface of a sheet to be fixed to pass through the surface of a heating roller having a surface formed of a material having releasability with respect to toner while contacting the surface under pressure. . In this method, since the surface of the heating roller and the toner image of the sheet to be fixed come into contact with each other under pressure, the thermal efficiency at the time of fusing the toner image onto the sheet to be fixed is extremely good, and the fixing can be performed quickly. Very effective in high-speed electrophotographic copying machines. However, in the above method, since the surface of the heating roller and the toner image come into contact with each other under pressure in a molten state, a part of the toner image adheres and transfers to the surface of the fixing roller, and the toner image re-transfers to the next sheet to be fixed. So-called offset development occurs, and the sheet to be fixed may be stained. Preventing toner from adhering to the surface of the heat fixing roller is one of the essential conditions of the heat roller fixing method.

That is, at present, it is desired to develop a binder resin for a toner having a wide fixing temperature range and a high offset resistance.

Also, studies and practical applications of two-color copying machines and full-color copying machines have been greatly increased. For example, "Journal of the Institute of Electrophotography" Vol22.No1 (1983) and "Journal of the Society of Electrophotography" Vol25.N
There is also a report on color reproducibility and gradation reproducibility as in o1.P52 (1986).

However, full color electrophotographic images that are currently in practical use are not necessarily directly compared with the real ones such as televisions, photographs, and color prints, and for those who see color images that are more beautifully processed than the real ones. It is not satisfactory.

In full-color electrophotography, multiple developments are performed, and several types of toner layers of different colors are required to be superimposed on the same support. Includes the following items.

(1) In order that the fixed toner does not diffusely reflect light and hinder color reproduction, the toner needs to be in a state of almost complete melting such that the shape of the toner particles cannot be determined.

(2) It must be a binder resin having transparency that does not interfere with the toner layers of different colors under the toner layer.

In this way, for monocolor copying machines, development of a binder resin for toner with a wide fixing temperature range and high offset resistance is desired. For full-color copying machines, not only the fixing temperature range is wide but also the transparency of the resin It is required that the fixing surface be flat when fixed.

Conventionally, for the purpose of widening the fixing temperature range of the polyester resin, JP-A-57-208559, JP-A-58-11954 and JP-A-59-228661 use an offset preventing agent. In the two-component system, the spent carrier is promoted, and the transparency of the toner is lost for a full-color toner.

JP-B-59-11902, JP-A-60-214368 and JP-A-59-7960 disclose the use of aromatic polycarboxylic acids. Therefore, the smoothness of the fixing surface of the toner is impaired, and the color mixing property for full color is poor.

JP-A-58-21160, JP-A-59-9969, and JP-A-59-29255 to 59-29260 make a crosslinked polyester by using a trivalent or higher polycarboxylic acid or polyol. Further, a method of cross-linking using a polyvalent metal compound is disclosed. However, even with these methods, the elasticity becomes too large, so that the smoothness of the fixing surface of the toner is impaired, and the color mixing property for full color is poor. .

That is, it is extremely difficult to simultaneously expand the fixing temperature range and simultaneously satisfy the toner characteristics of fluidity, durability, transparency, and smoothness of the fixing surface.

[Problems to be Solved by the Invention] An object of the present invention is to provide a novel color toner for color image formation in which these problems are improved.

That is, an object of the present invention is to provide a heat roller fixing toner resin having good fixability and particularly good offset resistance, and a method for producing the same.

It is a further object of the present invention to provide a heat roller fixing toner which has excellent fluidity, does not cause aggregation, and has excellent impact resistance.

It is a further object of the present invention to provide a heat roller fixing toner which has good chargeability, shows stable chargeability during use, and provides a clear and fog-free image.

Further, an object of the present invention is to provide a heat roller capable of forming a smooth fixing surface so that when used as a full-color toner, the fixed toner does not diffusely reflect light and hinder color reproduction. An object of the present invention is to provide a fixing toner.

It is a further object of the present invention to provide a toner which, when used as a full-color toner, has a transparency which does not interfere with a toner layer of a different color tone under the toner layer.

[Means and Actions for Solving the Problems] The present invention is directed to forming a color toner image by combining two or more types of color toners selected from the group consisting of cyan toner, magenta toner, yellow toner and black toner. In a color toner for forming a color image, the color toner contains at least a colorant and a polyester resin, and the polyester resin contains at least a polyhydric alcohol component, a polycarboxylic acid component, and a titanium coupling agent 0.5 to 0.5. Polyester resin synthesized using 25 mol% (based on the total mol of polyhydric alcohol component, polycarboxylic acid component and titanium coupling agent), and having a bond with Ti metal. A color toner for forming a color image.

When an aromatic trivalent or higher polycarboxylic acid and / or polyol conventionally used for crosslinking a polyester resin is used, the elasticity of the resin is increased, and the smoothness of the toner fixing surface is impaired for full color use. .

JP-A-59-9669 and JP-A-59-29255 to 59-29260 disclose a method of crosslinking with a polyvalent metal. However, after synthesizing a polyester, a polyvalent metal compound is added, and a mechanochemical compound is added. A method of crosslinking by a method is used. In the method of cross-linking after synthesizing polyester,
It is very difficult to uniformly disperse the polyvalent metal microscopically. Therefore, a difference in the crosslink density occurs partially. For this reason, when the molecular weight of the polyester is increased for the purpose of improving the offset resistance, the elasticity becomes too large, and the smoothness of the toner fixing surface is deteriorated for a full-color toner. On the other hand, if the molecular weight of the polyester is reduced for the purpose of improving the smoothness of the toner fixing surface, on the contrary, the offset resistance deteriorates.

Further, in these disclosed methods, the amount of the metal compound is reduced by using a polyester crosslinked with a trivalent or higher alcohol or carboxylic acid, but as described above, the trivalent or higher alcohol or carboxylic acid is used. It is very difficult to control the viscoelasticity of polyester with acid.

Therefore, the present inventor, as a result of intensive research, at the time of synthesis of the polyester resin, by performing a cross-linking reaction using a titanium coupling agent, by putting Ti in the main chain of the polyester resin to give a three-dimensional structure, Also for full-color toners, it is possible to expand the fixing temperature range without impairing the smoothness of the toner fixing surface.

The present inventors presumed the reason for this as follows. JP 58
According to JP-A-211160, a metal oxide, a metal salt, a hydroxide, an alkoxide, and a xylate compound are further combined with a tri- or higher-valent alcohol or a tri- or higher-valent carboxylic acid at the time of polyester synthesis to form a crosslinked structure. ing. But,
According to the patent, these metal compounds can bind only to the carboxyl group in the polyester resin. Therefore, only a bond with the carboxyl group at the unreacted portion of the trivalent or higher carboxylic acid or the carboxyl group at the terminal of the molecular chain can be expected.

Therefore, this method can partially form a three-dimensional structure, but cannot form a fine mesh structure.

Therefore, the fixability is improved to some extent but is not sufficient. In addition, it is possible to obtain a three-dimensional structure by metal cross-linking by using a large amount of a trivalent or higher carboxylic acid and forming a large amount of unreacted carboxyl groups. But
Since the crosslinking with a carboxylic acid having a valency of 3 or more proceeds simultaneously, the polyester resin obtained here becomes extremely rigid and has a poor smoothness on the toner fixing surface and cannot be used for a full-color toner.

According to the method of the present invention, a titanium coupling agent is used at the time of polyester synthesis, so that Ti metal is uniformly contained in the polyester main chain, and the metal serves as a branch point to have a three-dimensional structure. Further, since the reaction between the coupling agent and the acid or alcohol proceeds rapidly, a uniform and beautiful network structure can be formed. Therefore, it is considered that the fixing temperature range can be expanded without impairing the smoothness of the fixing surface for full-color toner.

As the polyhydric alcohol component of the polyester resin used in the present invention, ethylene glycol, propylene glycol, 1,3-butanediol, 1,4-butanediol,
2,3-butanediol, diethylene glycol, dipropylene glycol, triethylene glycol, 1,5-pentanediol, 1,6-hexanediol, neopentyl glycol, pentaerythritol diallyl ether, trimethylene glycol, 2-ethyl-1, 3-hexanediol, hydrogenated bisphenol A, and a bisphenol derivative represented by the following formula; (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)
~ 10. ) And the like.

As the polycarboxylic acid component, fumaric acid, maleic acid,
Citraconic acid, unsaturated dicarboxylic acids such as itaconic acid, or anhydrides thereof, succinic acid, adipic acid,
Examples thereof include dicarboxylic acids such as sebacic acid and azelaic acid, and acid anhydrides thereof, aromatic dicarboxylic acids such as phthalic acid and terephthalic acid, and lower alkyl esters thereof. Further, glycerin, sorbite, sorbitan and the like as trihydric or higher alcohols, and trimellitic acid, promellitic acid and the like as trivalent or higher acid, may be used in combination with the coupling agent described below. .

Examples of the titanate-based coupling agent used in the present invention include alkyl trialkaloyl titanates such as isopropyl trioctanoyl titanate and isopropyl triisostearoyl titanate; Acrylic alkaroyl titanates; alkyl cumyl phenyl titanates such as isopropyl tricumyl phenyl titanate; cumyl phenyl oxy acetate titanates such as dicumyl phenyl oxyacetate titanate and tetracumyl phenyl oxy acetate titanate; diisostearoyl ethylene titanate; Alkaloyl alkene titanates such as tetraisostearoyl ethylene titanate Alkyl tri (dialkyl phosphate) titanates such as isopropyl tri (dioctyl phosphate) titanate; tetraalkyl bis (dialkyl phosphite) titanates such as tetraisopropyl bis (dioctyl phosphite) titanate and tetraoctyl bis (ditridecyl phosphite) titanate ; Other tetra (2,2 diallyloxymethyl-1-butyl) bis (di-tridecyl) phosphite titanate, isopropyltris (dioctylpyrophosphate) titanate, bis (dioctylpyrophosphate) oxyacetate titanate, bis (dioctylpyrophosphate) Titanates containing phosphorus compounds such as ethylene titanate; oxopropyl tridodecylbenzenesulfonyl titanate, isopropyl Alkyltrimethylammonium benzene sulfonyl titanate such as belt RESTIR Lil benzenesulfonyl titanate; isopropyl tri (N- aminoethyl - aminoethyl) alkyl birds such as titanates (N- aminoalkyl - aminoalkyl) such as titanates and the like. Also, tetra n
-Tetraalkoxytitaniums such as propoxytitanium, tetra-i-propoxytitanium, tetra-n-butoxytitanium, tetrastearoxytitanium, tetrakis (2-ethylhexoxy) titanium; di-i-propoxybis (acetylacetonato) titanium, Dialkoxybis (acetylacetonato) titaniums such as -n-butoxybis (acetylacetonato) titanium; di-i-propoxybis (triethanolaminate) titanium, di-n
-Dialkoxybis (triethanolaminate) titaniums such as butoxybis (triethanolaminate) titanium; dihydroxybis (lactato) titanium and the like.

The alcohol component used in the present invention is 40 to 90mo
l%, the acid component is 40 to 90 mol%, and the titanium coupling agent is 0.5 to 2 based on the total moles of the polyhydric alcohol component, the polycarboxylic acid component and the titanium coupling agent.
It must be contained at 5 mol%. The trivalent or higher acid or alcohol component is 0 to 30 mol%, preferably 0 to 1 mol%.
Desirably, it is 5 mol%. Titanium coupling agent
If it is less than 0.5 mol%, there is no effect of improving the anti-offset property,
If the amount exceeds mol%, the crosslink density is too high, so that the smoothness of the fixing surface is impaired, and the fixing property is deteriorated due to the presence of many unreacted substances of the titanium coupling agent. Further, when the trivalent acid or alcohol is 30 mol% or more,
The smoothness of the toner fixing surface is impaired.

Among those specifically listed above, polyhydric alcohol components that can exert more effects in the present invention include:
Hydrogenated bisphenol A, bisphenol derivative represented by the following formula: (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
~ 10. The polyvalent carboxylic acid component includes lower alkyl esterified products such as fumaric acid, maleic acid, succinic acid, phthalic acid, terephthalic acid and trimellitic acid.

Examples of the titanium coupling agent include alkaloylalkene titanates, cumylphenyloxyacetate titanates, tetraalkylbis (dialkylphosphite) titanates, and the above-mentioned phosphorus-containing titanates, tetraalkoxytitaniums, dialkyi Coxybis (acetylacetonato) titaniums, dialkoxybis (triethanolaminate) titaniums, dihydroxybis (lacto) titaniums, and the like.

The reason is that a titanium coupling agent is used at the time of polyester synthesis, so that Ti metal uniformly enters the polyester skeleton, and the coupling agent serves as a branch point to form a uniform network structure.

Another reason is that these titanium coupling agents are rich in reactivity and can form a uniform network structure relatively easily.

Another reason is that the polyester obtained by using the lower alkyl ester of the acid, the alcohol, and the titanium coupling agent has excellent charging characteristics.

Another reason is that a polyester obtained by using a lower alkyl ester of the acid, an alcohol and a titanium coupling agent has excellent fluidity, does not cause aggregation, and has excellent impact resistance.

As a method for producing a polyester resin, the above compound is used under an inert gas atmosphere (in most cases, in the presence of nitrogen gas) under normal pressure to reduced pressure (0 to 750 mmH ₂ O). With stirring, the temperature is raised to 60 to 270 ° C, preferably to 80 to 220 ° C,
Incubate for 30 hours. Water or alcohols generated by the condensation polymerization are taken out of the system together with the inert gas while supplying the inert gas into the system so that the condensation polymerization proceeds.

For example, the compound is charged into a reaction vessel equipped with a stirrer, a condenser, a thermometer, and an inert gas introduction pipe. Next, gas replacement is performed by introducing an inert gas. After completion of the gas replacement, the reaction temperature is raised to a predetermined temperature by continuously flowing an inert gas, and the condensation polymerization reaction is carried out with stirring for 10 to 30 hours. Water or alcohol produced by the condensation polymerization reaction is condensed and collected by a condenser outside the system. At the end of the reaction, the temperature is lowered to stop the reaction, and the mixture is cooled to room temperature to obtain a polyester resin.

[Examples] Hereinafter, the present invention will be described in detail with reference to Examples.

Resin production example 1 Was placed in a 2 l four-neck round bottom flask equipped with a thermometer, a Teflon-coated stirring blade, a glass nitrogen introducing tube, a condenser, and a decompression device. After the by introduction of nitrogen gas reactor than the glass inlet tube an inert atmosphere, by adjusting the opening of the pressure reducing control valve and a nitrogen gas inlet valve, maintaining the system inside -750mmH ₂ O. Thereafter, the reactor was placed in a mantle heater and maintained at 190 ° C. to carry out a condensation polymerization reaction for 15 hours. Pressure at this time was also kept -750mmH ₂ O.

 The polyester obtained here is referred to as resin A.

Resin production example 2 Was performed in the same manner as in Resin Production Example 1. The condition at this time is 19
0 ° C., 14 hours, was -750mmH ₂ O.

 The polyester obtained here is referred to as resin B.

Resin production example 3 Was performed in the same manner as in Resin Production Example 1. The condition at this time is 21
0 ° C., was 25 hours, -750mmH ₂ O.

 The polyester obtained here is referred to as resin C.

Resin production example 4 Was performed in the same manner as in Resin Production Example 1 except that the reaction system was set to normal pressure. The reaction was performed at 200 ° C. for 12 hours. The polyester obtained here is referred to as resin D.

Resin production example 5 Was performed in the same manner as in Resin Production Example 4. The condition at this time is 22
The reaction was performed at 0 ° C. for 11 hours. The polyester obtained here is referred to as resin E.

Example 1 A full-color toner for dry electrophotography was obtained by using a coloring agent and a charge control agent in the following amounts with respect to 100 parts by weight of resin A.

The production method is that the above-mentioned formulation amounts are sufficiently preliminarily mixed with a Henschel mixer, melt-kneaded at least twice with a three-roll mill, cooled, roughly crushed using a hammer mill to about 1-2 mm, and then air-cooled. It was pulverized to a particle size of 40 μm or less by a jet-type pulverizer. Furthermore, the obtained finely pulverized product is classified, 2 to 23 μm is selected so as to have a particle size distribution of the present invention, and a silica fine powder treated with hexamethyldisilazane as a flow improver is added to 100 parts by weight of each classified product. 0.5 parts by weight of an external additive was added to obtain a color toner.

Also, a vinylidene fluoride-tetrafluoroethylene copolymer (copolymerization weight ratio of 8: 2) and styrene-2-ethylhexyl acrylate-methyl methacrylate (copolymerization weight ratio: 45:12 parts by weight) were used for 8 to 12 parts by weight of the color toner. 20:35)
About 50% by weight in a 50:50 weight ratio, Cu
-Zn-Fe ferrite carrier (average particle size 48 m; 250 mesh pass, 350 mesh on 79 wt%; true density 4.5 g / cm
³ ) was mixed to make a total amount of 100 parts by weight to prepare a developer.
Considering color tone reproducibility and toner scattering, yellow,
The developer concentrations of the magenta, cyan, and black color toners were 9%, 8%, 10%, and 10%, respectively. This is CLC-1
(Full color copying machine manufactured by Canon Inc.), and an image endurance test was performed. As a result, a clear image with no offset and no fog was obtained even with a durability of 25,000 sheets.

Example 2 It carried out similarly to Example 1 using resin B. as a result,
Even with a durability of 27,000 sheets, there was no offset and clear images without fog were obtained.

Example 3 It carried out similarly to Example 1 using resin C. as a result,
Even with a durability of 20,000 sheets, there was no offset and a clear image without fog was obtained.

Comparative Example 1 The same procedure as in Example 1 was performed using resin D. As a result, low-temperature offset occurred when the number of endurance sheets was 1,000. Further, the dispersion of the colorant of the cyan toner was poor, and the color reproducibility was poor.

Comparative Example 2 The same procedure as in Example 1 was performed using resin E. As a result, a low-temperature offset occurred when the number of durable sheets was 1200. The fixing surface was not flat, and the color mixing was poor.

[Effects of the Invention] The present invention is intended for full-color toners by adding a Ti into the main chain of the polyester resin and giving it a three-dimensional structure by performing a crosslinking reaction using a titanium coupling agent during the synthesis of the polyester resin. However, the smoothness of the toner fixing surface is not impaired, the fixing temperature range is expanded,
The toner can give a clear image without fogging.

Claims (2)

(57) [Claims] 1. A color image forming color toner for forming a color toner image by combining two or more kinds of color toners selected from the group consisting of a cyan toner, a magenta toner, a yellow toner and a black toner. The toner contains at least a colorant and a polyester resin. The polyester resin contains at least a polyhydric alcohol component, a polyvalent carboxylic acid component and 0.5 to 25 mol% of a titanium coupling agent (polyhydric alcohol component and polyvalent alcohol component). A polyester resin synthesized using a carboxylic acid component and a total amount of a titanium coupling agent) and having a bond with a Ti metal. toner. 2. The color toner for forming a color image according to claim 1, wherein the color image is a full color image having a cyan toner, a magenta toner, a yellow toner and a black toner.