JP2572065B2 - Liquid developer for electrostatic image development - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a liquid developer used for electrophotography, electrostatic recording, electrostatic printing, and the like.

(Prior art)

As a fixing method of toners, there are an open fixing method in which an electric heater passes through a heating atmosphere, a heat roll fixing method in which at least one of the pair is a heating roll, or a normal temperature between a pair of rigid rolls. A pressure fixing method for passing the pressure is known.

Almost all copiers using liquid developers used open fixing.

Among these fixing methods, the heat roll fixing method has extremely high thermal efficiency when the toner image is fused on the fixing substrate because the surface of the heating roll and the toner image holding surface on the fixing substrate are in pressure contact with each other. Since the image can be fixed quickly, it is extremely suitable especially for an image forming apparatus for high-speed copying.

In the heat roller fixing method, the toner comes into pressure contact with the surface of the heating roll in a heated and melted state, so that a part of the toner adheres to the roll surface, adheres again to the substrate to be fixed, and contaminates the image. There are drawbacks that can easily occur.

〔Purpose〕

SUMMARY OF THE INVENTION It is an object of the present invention to provide a novel liquid developer which does not cause offset development when using a heat roll fixing method which has high thermal efficiency and can perform high-speed fixing.

〔Constitution〕

In general, when a liquid developer is thermally fixed, a carrier liquid is present, so that toner particles are dissolved and swelled in the carrier liquid, so that the cohesive force of the toner layer is reduced and so-called “hot offset” tends to occur.

When the melt index of the toner is in the range of 0.01 to 10 g / 10 min (particularly preferably 0.1 to 4 g / 10 min (test conditions: temperature: 125 ° C., load: 10 kg, filling amount: 5 to 8 g), particularly excellent fixing characteristics are exhibited.

Therefore, the present inventors have proposed that Mw / Mn> 4, preferably Mw / Mn>
It has been found that by using a polymer having a molecular weight of 10 and Mw> 100,000 as a resin for a toner, a toner having good fixing properties can be obtained and no offset phenomenon occurs. Furthermore, when this polymer is lightly crosslinked by reaction with a decomposable metal compound, the molecular weight distribution becomes even wider,
It has been found that it is possible to provide the toner with offset resistance while keeping the minimum fixing temperature low.

As the decomposable metal compound used in the present invention, those containing the following metal ions can be used. Examples of the metal ion include metal ions having a valence of 1 or more. Suitable one
Valent metal ions include Na ⁺ , Li ⁺ , Cs ⁺ , Ag ⁺ , Hg ⁺ , Cu ⁺ , and suitable divalent metal ions are Ba ²⁺ , Mg ²⁺ , Ca ²⁺ , Hg ²⁺ , S
r ²⁺ , Pb ²⁺ , Fe ²⁺ , Co ²⁺ , Ni ²⁺ , Zn ²⁺ and the like. Suitable trivalent metal ions include Al ³⁺ , Se ³⁺ , Fe ³⁺ , Fo ³⁺ , CO ³⁺ , Ni
³⁺ , Cr ³⁺ , Y ³⁺ and the like. Among the above metal ion compounds, the more decomposable, the better the result.

As the polymer that reacts with the decomposable metal compound of the present invention, generally, a carboxy group, a carbonyl group, an ether group,
There are a thioether group, an amino group, an amide group and the like, and among these, a polymer containing a carboxyl group shows the best reactivity. Examples of the carboxyl group-containing monomer for synthesizing a vinyl polymer include, for example, acrylic acid, methacrylic acid, α-ethylacrylic acid, acrylic acid such as crotonic acid and α- or β-alkyl derivatives thereof, fumaric acid, maleic acid, Examples include unsaturated dicarboxylic acids such as citraconic acid and monoester derivatives thereof, and monomers copolymerizable with the above-mentioned carboxyl group-containing monomer include monocarboxylic acid derivatives having a double bond; for example, dibutyl maleate and maleic acid. Diester derivatives of dicarboxylic acids having a double bond such as dimethyl acid; vinyl esters such as vinyl chloride, vinyl acetate, vinyl benzoate; ethylene-based olefins such as ethylene, propylene, butylene;
Vinyl ketones such as vinyl methyl ketone and vinyl hexyl ketone; vinyl ethers such as vinyl methyl ether, vinyl ethyl ether and vinyl isobutyl ether; aromatic divinyl compounds such as vinyl benzene and divinyl naphthalene; For example, ethylene glycol diacrylate, ethylene glycol dimethacrylate, carboxylic acid ester having two intrinsic double bonds such as 1,3-butanediol dimethacrylate, divinyl aniline, divinyl ether, divinyl sulfide, divinyl compound such as divinyl sulfone and Examples include compounds having three or more vinyl groups.

Colorants that can be used in the present invention include Printex V, Printex U, Printex G, Special Black 15, Special Black 4, Special Black 4-B (manufactured by Degussa), Mitsubishi # 44, # 30, MR -1
1, MA-100 (Mitsubishi Kasei), Raven 1035, Raven 1252, New Spectra II (Columbia Carbon), Regal 400, 660, Black Pearl 900, 110
0, 1300, inorganic pigments such as Mogar L (from Cabot) and phthalocyanine blue, phthalocyanine green, sky blue, rhodamine lake, malachite green lake, methyl violet lake, peacock blue lake, naphthol green B, naphthol green Y, naphthol green Yellow S, naphthol red,
Lisor First Yellow 2G. Permanent Red 4
Organic pigments such as R, Brilliant Fast Scarlet, Hansa Yellow, Benzidine Yellow, Risor Red, Lake Red C, Lake Red D, Brilliant Carmine 6B, Permanent Red F5R, Pigment Scarlet 3B Indigo, Thioindigo Oil Pink and Bordeaux 10B. .

The pigment can be treated by kneading and pulverizing the above pigment with the above-mentioned resin using a two-roll, kneader, crusher or the like. Further, the following resin may be used together with the above resin.

Eastman Chemical Company N-10, N-11, N-12, N-14, N-34, N-35, C-10, C-13, C
−15, C−16, E−10, E−11, E−12, E−14, E−15, Mitsui Petrochemical Company 110P, 220P, 220MP, 820MP, 410MP, 210MP, 310MP, 405MP, 200
P, 4202E, 4053E Sanyo Chemical 131P, 151P, 161P, 171P, E300, E250P Sasol H1, H2, A1, A2, A3, A4 BASF (BASF) OA WAX, A WAX Petrolite (Vetro) BARECO) 500, BARECO (BARECO) 200, E-730, E
-2018, E-2020, E-1040, Petronaba
C, Petronaba C-36, Petronaba
ronaba) C-400, Petronaba C-7500 Hoechst PE580, PE130, PED121, PED136, PED153, PED521, PED522, PED
534 Union Carbide DYNI, DYNF, DYNH, DYNJ, DYNK Monsanto Oruzon 805,705,50 Dupont ALATHON 3,10,12,14,16,20,22,23 Allied Chemical Corporation AC polyethylene 6 , 6A, 615 Mitsui Polychemicals Evaflex 150,210,220,250,260,310,360,410,420,
Synthetic polyesters such as 450, 460, 550, 560, polypropylene and modified denatured carnauba wax, montan wax, candelilla wax, sugar cane wax, auricurie wax, beeswax, wood wax, natural wax such as wax, natural such as ester gum, hardened rosin Resin, natural resin modified maleic resin, natural resin modified phenolic resin,
Modified and cured natural resins such as modified natural resin polyester resin, modified natural resin pentaerythritol resin, and epoxy resin.

The dispersing resin of the present invention has a general formula Vinyl monomer A represented by the general formula Represented by a vinyl monomer and vinyl pyridine, vinyl pyrrolidone, ethylene glycol dimethacrylate,
One kind of each of the monomers B selected from styrene, divinylbenzene and vinyltoluene, or several kinds of copolymers and graft copolymers are used.

The amount of the dispersing resin used is the resin component 1 which is a feature of the present invention.
0.1 to 3 parts by weight, preferably 0.5 to 1.
Use at 5 parts by weight. Further, the total resin component that may be present in the toner composition is 5 to 1 part by weight per 100 parts by weight of the liquid component.
00 parts by weight, preferably 5 to 20 parts by weight.

As the carrier liquid, cyclohexane, n-hexane, n-hexane
-Petroleum aliphatic hydrocarbons such as heptane, n-nonane, n-octane, isooctane, isododecane, ligroin, and mixtures thereof (as commercial products, Isopar E, G, H, L, K and Shell Petroleum manufactured by Esso Standard Oil Co., Ltd.) (Solsol 71, Solvetso 150, etc.).

These coloring materials, resins, and carrier liquids are charged into a dispersing machine such as a ball mill, a kitty mill, a disc mill, a pin mill, and a vibration mill, and dispersed and kneaded.

[Examples] First, production examples of vinyl polymers having reactivity with decomposable metal compounds will be described.

Production Example 1 Toluene (40 parts by weight) was placed in a separable flask, and styrene (75 parts by weight), butyl methacrylate (20 parts by weight), maleic acid (5 parts by weight) and divinylbenzene (0.5 parts by weight) were added, and the gas phase was replaced with nitrogen gas. After that, keep at 80 ° C
A solution prepared by dissolving 0.3 parts by weight of benzoyl peroxide in 10 parts by weight was added dropwise using a dropping funnel replaced with nitrogen gas over 30 minutes, and the mixture was further stirred at 80 ° C. for 10 hours. Next, 5 parts by weight of a toluene solution containing 0.3 parts by weight of benzoyl peroxide was added dropwise, and the temperature was further raised to 90 ° C., and the temperature was maintained for 5 hours to complete the polymerization. After cooling, the polymer was precipitated in a large amount of methanol, and the precipitate was separated by filtration, dried at 60 ° C. and collected. This polymer had an Mw / Mn of 24 and an Mw of 216,000.

Production Example 2 As monomers, 80 parts by weight of styrene, 13 parts by weight of butyl acrylate, 2 parts by weight of acrylic acid, and 0.1 part of divinylbenzene.
The same procedure as in Production Example 1 was carried out except that 3 parts by weight were used. Mw / Mn was 19 and Mw was 138,000.

Production Example 3 Same as Production Example 1 except that 60 parts by weight of styrene, 10 parts by weight of methyl methacrylate, 20 parts by weight of butyl acrylate, 10 parts by weight of methacrylic acid, and 0.7 parts by weight of divinylbenzene were used as monomers. Done. Mw / Mn is 40
And Mw was 324,000.

Next, the reaction between the polymer and the decomposable metal compound was performed as follows.

Production Example 4 100 parts by weight of the polymer synthesized in Production Example 1 and 0.5 parts by weight of iron (III) acetylacetone (decomposition temperature: 340 ° C.) were kneaded at 150 ° C. for 30 minutes using a roll mill. The gel content of the crosslinked polymer was determined by extraction using toluene as a solvent. Gel content was 24%.

Production Example 5 100 parts by weight of the polymer synthesized in Production Example 2 was added to 100 parts by weight of xylene, dissolved while increasing the temperature, and heated to 130 ° C. To this polymer solvent, 1 part by weight of acetylacetonate cobalt (III) (decomposition temperature 210 ° C.) was added and reacted at 120 ° C. for 5 hours. After the reaction, xylene was removed to obtain a polymer. The gel content of the heated polymer was less than 1%.

Production Example 6 100 parts by weight of a polymer synthesized in Production Example 3
The reaction was carried out in the same manner as in Production Example 4, except that 2 parts by weight of chromium (III) salt of salicylic acid was used as the metal compound. Gel content was 32%.

Example 1 70 parts by weight of the resin of Production Example 1 30 parts by weight of Printex (Carbon Black, Degussa) were kneaded with two rolls and then pulverized.

50 parts by weight of the pulverized product lauryl methacrylate / methyl methacrylate /
Methacrylic acid / glycidyl methacrylate (80/10/5 /
5) 100 parts by weight of copolymer Isopar H solution 100 parts by weight Isopar H 200 parts by weight was placed in a ball mill and dispersed for 24 hours.
Was added and dispersed for 1 hour to obtain a concentrated toner. 200 g of this was diluted in Isopar H1 and used as a developer.

Example 2 57 parts by weight of the resin of Production Example 2 250 parts by weight (Sanyo Chemical Polyethylene) 8 parts by weight MA60 (Mitsubishi Chemical Carbon Black) 35 parts by weight was kneaded with a crusher and then ground.

60 parts by weight of the pulverized product stearyl methacrylate / methyl methacrylate / methacrylic acid / hydroxymethyl methacrylate (85/7/4 /
4) Copolymer Isopar H 10% solution 200 parts by weight Isopar H (EXXSON) 100 parts by weight The same procedure as in Example 1 was carried out.

Example 3 60 parts by weight of the resin of Production Example 3 10 parts by weight of AC400A (Allied Chemical) 30 parts by weight of Regal 400 (Cabot) were kneaded and pulverized with a crusher. Hereinafter, it carried out similarly to Example 1.

Comparative Example In Example 1, a styrene resin was used as a developer instead of the resin of Production Example 1 to prepare a developer.

After outputting an image with a fixing heater off with a Ricoh CT5085, the non-offset area was examined with a fixing tester. The results are shown in the table below.

As is apparent from the above results, the present invention provides a wide temperature range capable of fixing with a heat roller that does not exhibit an offset phenomenon, and enables fixing with a heat roller.

〔effect〕

The developer of the present invention enables heat roller fixing without causing an offset phenomenon, and facilitates high-speed fixing.

Further, the liquid developer of the present invention can perform high sharpness-free fixing without blurring even by a flash fixing method.

 ──────────────────────────────────────────────────続 き Continuation of the front page (72) Inventor Shinichi Kuramoto 1-3-6 Nakamagome, Ota-ku, Tokyo Inside Ricoh Co., Ltd. (56) References JP-A-63-4249 (JP, A) JP-A-53-22440 (JP, A) JP-A-62-62368 (JP, A) JP-A-61-188545 (JP, A) JP-A-59-148067 (JP, A) JP-A-60-10263 (JP, A) , A) JP-A-50-30528 (JP, A)

Claims (2)

(57) [Claims] 1. A liquid developer for electrophotography comprising toner particles dispersed in a carrier liquid containing an aliphatic hydrocarbon as a main component, wherein the weight average molecular weight / number average molecular weight (Mw / Mn) is greater than 4.0. A liquid developer for electrophotography, comprising a vinyl polymer in toner particles. 2. A liquid developer for electrophotography comprising toner particles dispersed in a carrier liquid containing an aliphatic hydrocarbon as a main component, wherein the weight average molecular weight / number average molecular weight (Mw / Mn) is greater than 4.0. A liquid developer for electrophotography, wherein a polymer obtained by reacting a vinyl polymer with a decomposable metal compound is contained in toner particles.