JP3096873B2 - Method for producing toner for developing electrostatic images - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a toner including a step of melting and kneading a toner for developing an electrostatic image and a magnetic latent image in electrophotography, electrostatic printing, magnetic recording and the like. The present invention relates to a toner manufacturing method including a step of melting and kneading a toner for developing an electrostatic image used in a heat fixing method.

[0002]

2. Description of the Related Art Toners for electrophotography are prepared by using a ball mill, Henschel mixer, and other raw materials such as a binder resin and wax (release agent), a charge control agent, a magnetic material as required, a pigment or dye as a colorant, and additives. Pre-mixed by a mixer such as the above, melt-kneaded using a kneading apparatus such as a heating roll, kneader, extruder, etc., cooled and solidified, roughly pulverized by a hammer mill, etc., and then finely pulverized by a jet mill, etc. It is manufactured by doing. In the melt-kneading step at this time, it is necessary to uniformly disperse the wax, the charge control agent, and the like in the binder resin.
If poor dispersibility occurs, the subsequent pulverization, uneven distribution of the wax component in the classification step, or release, etc., or the charging characteristics are deteriorated, thereby causing image stains such as fog, photosensitive members, developer carrying members and the like. This may cause the surface of the charging member to be contaminated.

[0003] As described above, the melt-kneading step is an important step in toner production. As a kneading apparatus usually used for producing a toner, a twin-screw extruder is used because continuous production is possible.

[0004] In a twin-screw extruder, two rotating shafts called paddles pass through a heating cylinder for maintaining a constant temperature. The raw material is supplied from one end of a heating cylinder, heated, melted, kneaded by rotation of a paddle, and extruded from the other end. A vent hole whose main purpose is deaeration may be installed on the way.

FIG. 2 is a schematic view of a paddle. The cross section of the paddle may be a propeller-shaped one or a triangular-shaped one as shown in the figure, and is set out of phase so that one tip always rotates as if rubbing the other. This structure has a self-cleaning action of sending the kneaded material forward without adhering to the paddle and the cylinder wall. The directions of rotation of the two paddles may be the same or different, but the same direction is common.

[0006] The paddle is roughly composed of two types of parts, one of which is a feed screw portion, and a schematic diagram thereof is shown in FIG. This part is an S spiral screw that has the function of heating the kneaded material and sending it forward.If the viscosity of the kneaded material in the cylinder is high, the shear force due to the friction between the wall of the screw part and the kneaded material It is kneaded, but if it is low, it is hardly kneaded. The other is kneading, where kneading is mainly performed. Here, a combination of a propeller-like block as shown in FIGS. 4 and 5, a pineapple-like block as shown in FIG. 6, a return screw for feeding in the direction opposite to the extrusion, and the like are used. This portion has almost no effect of sending the kneaded material forward, and the kneaded material stays and fills. The kneading is performed in response to the volume change of the compression and the stretching accompanying the rotation of the paddle. If the kneading portion is short or absent, the kneaded material hardly stays and is extruded before the kneaded material is completely melted. The setting conditions of the extruder include a heating temperature, a paddle configuration, a paddle rotation speed, a raw material supply amount, and the like.

Conventionally, when a toner is manufactured, a wax is added to a binder resin and mixed and kneaded only at the time of melt-kneading, and when a wax having a relatively low melting point and low viscosity which is effective for low-temperature fixability is used. Has poor compatibility with the binder resin and tends to cause poor wax dispersibility. Therefore, a wax having a relatively high melting point and high viscosity is usually used. In order to improve the dispersibility of the wax, the magnetic material, and the like, kneading conditions for increasing the shearing force applied to the kneaded material during kneading, that is, the kneading portion are set to be somewhat longer. However, in this case, the dispersibility is improved to some extent, but the kneading causes the molecular chains of the binder resin in the toner to be cut, and the molecular weight of the toner is reduced, and the offset resistance, particularly the offset resistance at a high temperature side, is deteriorated. Or a problem in practical use such as deterioration of blocking resistance. In addition, when the fine powder, coarse powder, and the like distributed in the classification step are repeatedly produced by reuse, there is a problem that the yield is reduced.

[0008]

SUMMARY OF THE INVENTION An object of the present invention is to provide a method for producing a toner for developing an electrostatic image, which solves the above-mentioned problems.

That is, the fixing property and the anti-offset property, especially the anti-offset property in a wide temperature range from a low temperature to a high temperature, are very excellent, and the image density without image stains such as fog and the contamination of the charging member is stable over a long period of time. An object of the present invention is to provide a method for manufacturing a toner for image development.

Another object of the present invention is to provide a method for producing a toner for developing an electrostatic charge image having a good dispersibility of a wax or a magnetic substance.

[0011]

SUMMARY OF THE INVENTION The present invention relates to a method for producing a toner containing at least a binder resin internally added to a wax, which is obtained by mixing at least one kind of wax and a resin in a solution and removing the solvent. A kneading device in which a paddle is provided in the axial direction, the screw L / D is 23 or more, the kneading part is at two or more places, and the L _n / D of all the kneading parts is 6 or less. (Invention 1). (Where, L is a paddle total length, L _n is the total kneading portion of the length, D is represents the screw diameter.) Further, the present invention is a molecular weight distribution by GPC, at least one of the 2 × 10 ⁵ or more regions A method for producing a toner containing at least a binder resin having a peak, comprising a step of melting and kneading toner raw materials with the above kneading apparatus (Invention 2).

Further, the present invention provides a method for producing a toner containing at least a binder resin and a magnetic material, wherein the bulk density of the magnetic material is 0.9 g / cm ³ or less, and the toner raw material is melted by the above kneading apparatus. It is characterized by including a step of kneading (Invention 3).

The kneading apparatus according to the present invention comprises a screw L
/ D is 23 or more, and L / D is 25 to
Preferably it is 35. If the L / D is less than 23, the time required for melt-kneading the kneaded material becomes short, causing poor dispersibility of wax or the like, causing not only image stains such as fog or defective image density, but also uneven distribution of wax or the like. It is not preferable because the release also deteriorates the offset resistance.

FIG. 1 is a schematic view of a kneading apparatus according to the present invention. As shown in this figure, it is necessary to have two or more kneading parts, and by passing through two or more kneading parts, the kneaded material can be completely melted and the dispersibility can be improved. can do. Further, L _k / D of all kneading portions is 6 or less, the shearing force applied to the kneaded material during kneading is small, the molecular chains of the binder resin are less cut, and the offset resistance, particularly at high temperature, Has good offset resistance. From the balance between dispersibility and molecular chain cleavage, L _n / D is particularly preferably 1 to 4. If there is only one kneading portion, the stagnation is insufficient and poor dispersibility is likely to occur. At this time, if the kneading portion is lengthened in order to improve the dispersibility, the offset resistance on the high temperature side deteriorates due to the breaking of the molecular chain. Accordingly, the number of kneading portions is increased to two or more, and L _n /
By reducing D, it is possible to suppress breakage of the molecular chain and improve dispersibility.

As the paddle of the kneading part of the present invention, any paddle having the effect of retaining the kneaded material, such as those having the shapes shown in FIGS. 4, 5, and 6 and return screws, can be used. They can be used in combination of several types.

Next, the features of the binder resin according to the invention 1 or 2 of the present invention and the features of the magnetic material according to the invention 3 will be described.

The binder resin according to the first aspect of the present invention needs to be a binder resin in which wax is previously added.

The binder resin can be produced by adding a wax to a solution-polymerized resin solution, mixing the solution, and removing the solvent, or by suspending, bulk-polymerizing, or emulsion-polymerizing the resin and the wax, such as toluene or xylene. The resin and the wax can be mixed by any method such as a method of dissolving in an organic solvent, mixing the solution, and removing the solvent.

By adding wax to the resin in advance, even if a wax having a relatively low melting point and low viscosity is used, the effect of the present invention can be exerted.

Since the dispersibility of wax and the like is improved by using the above binder resin, it is possible to reduce L _n / D of all kneading portions. In addition, the melting at the time of kneading is fast, and the viscosity of the kneaded material tends to be small,
By reducing the shearing force applied to the kneaded material during kneading, it is possible to prevent the molecular chains of the binder resin from being cut due to kneading. Accordingly, it is possible to obtain a toner having excellent offset resistance, good dispersibility of wax and the like, and stable image density for a long period without image stains such as fog and contamination of the charging member. Further, a good toner can be obtained even when the fine powder or coarse powder or the like distributed in the classification step is reused and repeatedly produced.

The binder resin according to Invention 2 of the present invention is characterized in that at least one peak exists in a region of 2 × 10 ⁵ or more, preferably 3 × 10 ⁵ or more in molecular weight distribution by GPC. ^{3 ~5} × 10 ^4,
Preferably, a peak also exists at 5 × 10 ^{3 to} 3 × 10 ⁴ from the viewpoint of achieving both offset resistance and fixability. For example, a mixed system of a low-molecular resin and a high-molecular resin, a mixed system of a low-molecular resin and a crosslinked resin, a two-stage polymerization system, and the like can be given. Further, the weight mixing ratio of the low-molecular resin and the high-molecular resin or the cross-linked resin (low-molecular resin: high-molecular resin) is 50:50
90:10, preferably 55:45 to 85: 1
5

A resin having a peak in a region of 2 × 10 ⁵ or more is very effective in offset resistance on a high temperature side.
In the conventional kneading method, the molecular chain is easily broken at the time of kneading, and the effect has not been sufficiently exhibited. However, in the kneading method according to the present invention, the breaking of the molecular chain is suppressed, so that the effect can be exerted extremely effectively. In addition, in the conventional method, in order to obtain a sufficient offset resistance on the high-temperature side, it is necessary to contain a large amount of a high-molecular resin, thereby reducing the content of a low-molecular resin effective for fixing properties, The fixing property becomes inferior.

The use of the above binder resin and setting L _n / D of all kneading portions to 6 or less, that is, reducing the shearing force applied to the kneaded material during kneading, thereby cutting the polymer chains of the binder resin by kneading. Can be suppressed. As a result, even when the content of the polymer resin in the binder resin is small, the elasticity of the toner at the time of melting can be kept high, so that the content of the low-molecular resin can be increased, and the offset resistance and the fixing property can be improved. A toner excellent in both properties can be obtained.

However, L _n / D of all kneading portions is 6
If it is larger, the polymer chains of the binder resin are cut by kneading, and the offset resistance on the high temperature side deteriorates. As a result, it is necessary to increase the content of the polymer resin, and the viscosity value of the toner at the time of melting increases, and the fixability deteriorates.

The magnetic material according to Invention 3 of the present invention has a bulk density of 0.9 g / cm ³ or less, preferably 0.2 to 0.8 g / cm ³ , more preferably 0.3 to 0.8 g / cm ³ .
０．７0.7 g / cm ³ .

By setting the bulk density of the magnetic material in the above range, the magnetic material can be easily mixed uniformly at the time of mixing with the binder resin or the like before the melt-kneading, and the dispersion of the magnetic material can be kept in a good state in advance. Therefore, even when the shearing force applied to the kneaded material during the melt-kneading is small, it can be sufficiently dispersed.

If the bulk density of the magnetic material is greater than 0.9 g / cm ³ , the magnetic material tends to be unevenly distributed during pre-mixing and hardly mixes during kneading, causing poor dispersibility of the magnetic material and causing fogging and the like. If image shearing is likely to occur, and if the shearing force applied to the kneaded material during kneading is increased in order to prevent it, the molecular chains of the binder resin will be cut and the offset resistance will deteriorate. If the bulk density of the magnetic material is too small, the supply amount of the raw materials during kneading is not stable, and the kneading process is unstable, the kneading conditions are not stable, a uniform toner cannot be obtained, and an image such as fog is formed. Dirt and contamination of charging members,
An image density defect occurs.

The method for producing the magnetic material is not particularly limited, and the magnetic material may be subjected to dusting or pulverization to obtain a desired bulk density.

Since the dispersibility of the magnetic material is improved by using the above magnetic material, it is possible to reduce L _n / D of all the kneading portions. Further, by reducing the shearing force applied to the kneaded material during kneading, it is possible to prevent the molecular chains of the binder resin from being cut due to kneading. Accordingly, it is possible to obtain a toner having excellent offset resistance, good dispersibility of the magnetic substance, and stable image density for a long time without image fouling or the like.

The magnetic material used in Invention 3 of the present invention includes:
Alloys and compounds containing ferromagnetic elements, such as iron oxides such as magnetite, maghemite, and ferrite or compounds of divalent metals and iron oxides; metals such as iron, cobalt, and nickel; or aluminum and cobalt of these metals , Copper, lead, magnesium, tin, zinc, antimony,
Conventionally known magnetic materials include alloys of metals such as beryllium, bismuth, cadmium, calcium, manganese, selenium, titanium, tungsten, and vanadium, and mixtures thereof.

These magnetic materials have an average particle size of 0.1 to 2
μm, preferably about 0.1 to 0.5 μm. The content is about 20 to 20 with respect to 100 parts by mass of the resin.
0 parts by mass, preferably 40 to 150 parts by mass.

The bulk density of the magnetic material according to Invention 3 is determined according to JIS.
-Measured according to K5101.

The resin used in the present invention includes, as monomers to be formed, styrene such as styrene, α-methylstyrene, p-methylstyrene, p-chlorostyrene, and vinyltoluene, and their substituted products; methyl acrylate, acrylic acid Acrylates such as ethyl, n-butyl acrylate and t-butyl acrylate; methyl methacrylate, ethyl methacrylate, n-butyl methacrylate, t-butyl methacrylate, 2-ethylhexyl methacrylate, cyclohexyl methacrylate; Methacrylic acid esters such as acrylonitrile; vinyl ethers such as vinyl methyl ether and vinyl ethyl ether; maleic acid;
Unsaturated carboxylic acids such as maleic acid esters; unsaturated carboxylic acid esters; olefins such as ethylene, propylene and butadiene; and diolefins. Monomers of these monomers, copolymers of two or more monomers, and polyesters, non-linear polyesters, polyethers, polyamides, epoxy resins, polyamides, terpene resins, and phenol resins alone Alternatively, they can be used as a mixture.

In the polymerization of the above-mentioned monomers, the polymerization can be carried out in the presence of an initiator and in the presence or absence of a crosslinking agent.

In the present invention, styrene-acrylate copolymers, styrene-methacrylate copolymers and polyester resins are preferred as the resin in terms of appropriate affinity with the release agent of the present invention, Crosslinked styrene-acrylic ester copolymers, crosslinked styrene-methacrylic ester copolymers, and non-linear polyester resins are preferred in terms of properties and durability, and in terms of achieving both offset resistance and low-temperature fixability, resins are preferred. It is preferable that the molecular weight distribution has at least two or more peaks. For example, a mixed system of a low molecular resin and a high molecular resin of the above resin, a mixed system of a low molecular resin and a crosslinked resin, and a monomer constituting the above resin are used. Two-stage polymerization systems and the like can be mentioned.

As an initiator, t-butyl peroxy 2
-Ethyl hexanoate, cumin perpivalate, t-
Butylperoxylaurate, benzoyl peroxide, lauroyl peroxide, octanoyl peroxide, di-t-butyl peroxide, t-butylcumyl peroxide, dicumyl peroxide, 2,
2'-azobisisobutyronitrile, 2,2'-azobis (2-methylbutyronitrile), 2,2'-azobis (2,4-dimethylvaleronitrile), 2,2'-azobis (4- Methoxy-2,4-dimethylvaleronitrile), 1,1-bis (t-butylperoxy) 3,3
5-trimethylcyclohexane, 1,1-bis (t-butylperoxy) cyclohexane, 1,4-bis (t-
Butylperoxycarbonyl) cyclohexane, 2,2
-Bis (t-butylperoxy) octane, n-butyl 4,4-bis (t-butylperoxy) valerate,
2,2-bis (t-butylperoxy) butane, 1,3
-Bis (t-butylperoxy-isopropyl) benzene, 2,5-dimethyl-2,5-di (t-butylperoxy) hexane, 2,5-dimethyl-2,5-di (benzoylperoxy) hexane , Di-t-butyldiperoxyisophthalate, 2,2-bis (4,4-di-t-
Butylperoxycyclohexyl) propane, di-t-
Butyl peroxy α-methyl succinate, di-tert-butyl peroxydimethyl glutarate, di-tert-butyl peroxyhexahydroterephthalate, di-tert-butyl peroxyazelate, 2,5-dimethyl-2,5 −
Di (t-butylperoxy) hexane, diethyl glycol bis (t-butylperoxycarbonate), di-
Examples thereof include t-butylperoxytrimethyl adipate, tris (t-butylperoxy) triazine, and vinyltris (t-butylperoxy) silane, which may be used alone or in combination.

As the cross-linking agent, compounds having two or more polymerizable double bonds are mainly used, for example, aromatic divinyl compounds such as divinylbenzene, divinylnaphthalene, etc .; for example, ethylene glycol diacrylate, ethylene glycol Dimethacrylate, 1,3
A carboxylic acid ester having two double bonds such as butadiol dimethacrylate; divinylaniline,
Divinyl compounds such as divinyl ether, divinyl sulfide and divinyl sulfone; and compounds having three or more vinyl groups are used alone or as a mixture.

The wax used in the present invention has a melting point of 7
0-155 ° C, melt viscosity at 140 ° C is 800c
P or less, melting point of 75 to 145 ° C
It is more preferable that the melt viscosity at 140 ° C. is 500 cP or less, and the melting point is 80 to 135 ° C.
It is particularly preferred that the melt viscosity at 300C be 300 cP or less. Specific examples include paraffin wax,
Micro wax, Fischer-Tropsch wax,
Montan wax, ethylene, propylene, butene
Linear α- such as 1, pentene-1, hexane-1, heptene-1, octene-1, nonene-1, decene-1
Branched α- such that the olefin and the branched moiety are terminated
Examples thereof include homopolymers of olefins and olefins having different positions of these unsaturated groups, and copolymers thereof.

Further, a modified wax obtained by subjecting a block copolymer or graft modification with a vinyl monomer may be used.

The amount of the wax added is 0.5 to 10 parts by mass, preferably 1 to 8 parts by mass, per 100 parts by mass of the resin. In addition, you may add together two or more types of waxes.

In the present invention, the melting point of the wax is determined by using a suggestive scanning calorimeter of internal combustion type input compensation type (for example, DSC-7 manufactured by PerkinElmer) at a heating rate of 10 ° C./mi.
n, measured according to the temperature measurement pattern of ASTM D3418, and taken as the peak top value of the highest melting temperature,
The melt viscosity of the wax was measured using a Brookfield viscometer (for example, LVTDV-I manufactured by ST Johnson).
Using I), a temperature of 140 ° C. and a shear rate of 1.32 rpm
m, measured under the conditions of a sample of 10 ml.

In the present invention, a conventionally known positive or negative charge control agent is used as the charge control agent. Today, charge control agents known in the art include:

(1) The following substances control the toner to be positively charged. Modified products such as nigrosine and fatty acid metal salts, tributylbenzylammonium-1-
Quaternary ammonium salts such as hydroxy-4-naphthosulfonate and tetrabutylammonium tetrafluoroborate, and onium salts such as phosphonium salts which are analogs thereof, and lake pigments thereof, triphenylmethane dyes and lakes thereof Pigments, metal salts of higher fatty acids (for example, phosphotungstic acid, phosphomolybdic acid, phosphotungsten molybdic acid, tannic acid, lauric acid, gallic acid, ferricyanide, ferrocyanide); dibutyltin oxide, dioctyl Diorganotin oxides such as tin oxide and dicyclohexyltin oxide; diorganotin borates such as dibutyltin borate, dioctyltin borate and dicyclohexyltin borate: alone or in combination of two or more It can be used in conjunction. Among these, charge control agents such as lake pigments of nigrosine, quaternary ammonium salts and triphenylmethane dyes are particularly preferably used.

In addition, the general formula

[0045]

Embedded image [R ₁ : H, CH ₃ R ₂ , R ₃ : a substituted or unsubstituted alkyl group (preferably C ₁ -C ₄ )] homopolymer of a monomer: styrene, acrylate, methacrylic acid described above A copolymer with a polymerizable monomer such as an ester can be used as a positive charge control agent. In this case, these charge control agents also act as (all or part of) the binder resin.

The following substances control the toner to be negatively charged.

For example, an organic metal complex and a chelate compound are effective, and examples thereof include a monoazo metal complex, an acetylacetone metal complex, an aromatic hydroxycarboxylic acid, and an aromatic dicarboxylic acid-based metal complex. Other examples include aromatic hydroxycarboxylic acids, aromatic mono- and polycarboxylic acids and their metal salts, anhydrides, esters, and phenol derivatives such as bisphenol.

The toner of the present invention may optionally contain additives. As the additive, for example, a lubricant such as Teflon, zinc stearate, and polyvinylidene fluoride, among which polyvinylidene fluoride is preferable. Alternatively, abrasives such as cerium oxide, silicon carbide, and strontium titanate, among which strontium titanate is preferable. Alternatively, for example, a fluidity-imparting agent such as colloidal silica and aluminum oxide, particularly hydrophobic colloidal silica is preferable. An anti-caking agent or a conductivity-imparting agent such as carbon black, zinc oxide, antimony oxide, and tin oxide can also be used. Further, a small amount of white fine particles and black fine particles of opposite polarity can be used as a developing property improver.

When the toner of the present invention is used as a two-component developer, it is used by mixing with a carrier powder. In this case, the mixing ratio of the toner and the carrier powder is 0.1 to 50% by weight as the toner concentration, preferably 0.5%.
-15% by weight, more preferably 3-5% by weight.

In the present invention, known carriers can be used as the carrier, for example, magnetic powders such as iron powder, ferrite powder and nickel powder, glass beads and the like, and the surfaces thereof are made of fluorine resin or acrylic resin. Alternatively, those treated with a silicon resin or the like may be used.

Further, the toners of the inventions 1 and 2 of the present invention contain a magnetic material and can be used as a magnetic toner similarly to the invention 3. In this case, the magnetic material, the average particle size, and the content are the same as those of the third aspect.

Further, a coloring agent may be added to the toner of the present invention, if necessary.

In the present invention, any suitable pigment or dye is used as the colorant. Toner colorants are well known and include pigments such as carbon black, aniline black, acetylene black, naphthol yellow, hansa yellow, rhodamine lake, alizarin lake, bengalara, phthalocyanine blue, and induslen blue. These are used in an amount necessary and sufficient to maintain the optical density of the fixed image, and are preferably added in an amount of 0.1 to 20 parts by mass, preferably 0.2 to 10 parts by mass based on 100 parts by mass of the resin. A dye is further used for the same purpose.

For example, there are azo dyes, anthraquinone dyes, xanthene dyes, methine dyes and the like.
0.1 to 20 parts by mass, preferably 0.3 to 0 parts by mass
The addition amount of from 10 to 10 parts by mass is good.

The toner obtained by the production method according to the present invention is heat-fixed to a transfer material such as plain paper or a transparent sheet for an overhead projector (OHP) by contact heat fixing means.

As the contact heating fixing means, a heating / pressing roll fixing device, or a pressurizing apparatus which presses a fixedly supported heating element against the heating element and makes the transfer material adhere to the heating element via a film. Depending on the member, a fixing unit that heats and fixes the toner may be used.

[0057]

EXAMPLES The present invention will be described in more detail with reference to the following Examples, which do not limit the present invention in any way.
Examples 1 to 4 relate to Invention 1, Examples 5 to 9 relate to Invention 2, and Examples 10 to 16 relate to Invention 3. Parts in the following Examples and Comparative Examples are parts by mass unless otherwise specified.

Table 1 shows the paddle structure of the kneading apparatus (twin-screw extruder) used in Examples 1 to 4 or Comparative Examples 1 to 4.
The kneading paddle used had the shape shown in FIGS.

[0059]

[Table 1] Example 1 Binder resin 1 104 parts Magnetic substance 80 parts Nigrosine dye 2 parts Binder resin 1 is a styrene-n-butyl acrylate copolymer (Mn = 6900, Mw = 190,000) 100
Parts and low molecular weight polyethylene (melting point 118 ° C, 140 ° C
(Melt viscosity at 25 cP) was dissolved completely in xylene, stirred for about 1 hour, and then xylene was removed.

After premixing these raw materials with a Henschel mixer, the heating temperature was set to 130 in a kneading apparatus (1).
The mixture was melt-kneaded at a temperature of 120 ° C. and the paddle rotation speed was set to 120 rpm. After cooling and solidifying, the kneaded product was pulverized and classified to obtain a toner having a weight average particle size of about 8 μm. Further, only the fine powder and coarse powder sorted in the classification process were re-kneaded to produce a reused toner. To 100 parts of this toner, 0.8 part of hydrophobic colloidal silica was dry-mixed to obtain Toner 1. This toner is
The toner did not contaminate the developing sleeve and the photoreceptor, had good cleaning properties, and had no problem in durability.

FIG. 7 shows a schematic diagram of the paddle structure of the kneading apparatus (1).

Comparative Example 1 Comparative toner 1 was obtained in the same manner as in Example 1 except that the mixture was melted and kneaded by the comparative kneading apparatus (1).

Example 2 104 parts of binder resin 2 70 parts of magnetic substance 2 parts of nigrosine dye 2 parts of binder resin 2 were 100 parts of styrene-n-butyl acrylate copolymer (Mn = 7600, Mw = 210,000)
And Fischer-Tropsch wax (melting point 106
The melt viscosity at 140 ° C. and 140 ° C. was 6 cP).

After premixing these raw materials with a Henschel mixer, the heating temperature was set to 130 in a kneading apparatus (2).
The mixture was melt-kneaded at a temperature of 120 ° C. and the paddle rotation speed was set to 120 rpm. After cooling and solidifying, the kneaded product was pulverized and classified to obtain a toner having a weight average particle size of about 8 μm. Further, only the fine powder and coarse powder sorted in the classification process were re-kneaded to produce a reused toner. To 100 parts of this toner, 0.6 part of hydrophobic colloidal silica was dry-mixed to obtain Toner 2.

Comparative Example 2 Comparative toner 2 was obtained in the same manner as in Example 2 except that the mixture was melted and kneaded by the comparative kneading device (2).

The uneven distribution and release of the wax were observed in the toner, and the fixability and the developability were not satisfactory.

Example 3 Binder resin 3 104 parts Magnetic material 80 parts Monoazo dye metal complex 3 parts Binder resin 3 is a styrene-n-butyl acrylate copolymer (Mn = 6500, Mw = 240,000) 100
Parts and low molecular weight polypropylene (melting point is 135 ° C, 140
(Melt viscosity at 98 ° C .: 98 cP) 5 parts by solution mixing as in Example 1.

After premixing these raw materials with a Henschel mixer, the mixture was heated to a heating temperature of 140 with a kneading device (3).
The mixture was melt-kneaded at a temperature of 120 ° C. and the number of revolutions of the paddle was set to 120 rpm. Further, only the fine powder and coarse powder sorted in the classification process were re-kneaded to produce a reused toner. To 100 parts of this toner, 0.8 part of hydrophobic colloidal silica and 2.0 parts of strontium titanate were dry-mixed to obtain Toner 3.

[0069] The addition was melt-kneaded in Comparative Example 3 Comparative kneading apparatus (3) in the same manner as in Example 3 to obtain a comparative toner 3.

The uneven distribution and release of the wax in the toner were observed, and neither good fixability nor good developability could be said.

Example 4 A toner 4 was obtained in the same manner as in Example 1 except that the kneading was performed by the kneading apparatus (4).

Comparative Example 4 Styrene-n-butyl acrylate copolymer 100 parts Low molecular weight polyethylene 4 parts Magnetic material 80 parts Nigrosine dye 2 parts Same as Example 1 except that the binder resin did not previously contain wax. Using the above raw materials, Comparative Toner 4 was obtained in the same manner as in Example 1.

The uneven distribution and release of the wax were observed in the toner, and neither good fixability nor good developability could be said. In particular, early black spots were noticeable. Contamination was also observed on the developing sleeve.

The following tests were conducted on the above toner.
Table 2 shows the results.

Fixability and Offset Resistance Test An unfixed image was obtained with a commercially available copying machine NP-1215 (manufactured by Canon Inc.) (however, Example 3 and Comparative Example 3 were subjected to reversal development). Fixing was performed using a printer, and a fixing property and an offset resistance test were performed. In addition,
This external fixing machine has a nip of 2.5 mm and a linear pressure of 0.5 kg /
cm, process speed 50 mm / sec and 100
The temperature was controlled at 5 ° C. intervals in a temperature range of ２３０230 ° C. 80 g / m ² paper was used for the fixability test, and 52 g / m ² paper was used for the offset resistance test.

The fixing start temperature is set at 50 g / m ² for the fixed image.
With a load of silbon paper (Lenz cleanin)
g paper “dasper (R)” Ozu P
aper Co. Ltd.), and the temperature at which the density reduction rate before and after rubbing is less than 10% was set to a temperature at which the offset does not appear visually when the temperature was increased.

Developability (image density, fog) Test toners 1, 2, and 4 and comparative toners 1, 2, and 4 were continuously copied on 10,000 sheets by a commercially available copying machine NP-1010 (manufactured by Canon Inc.). , Toner 3 and Comparative Toner 3 were copied on a commercial laser beam printer LBP-8II on 4000 sheets and evaluated for developability (image density, fog). The image density was measured with a reflection densitometer, and fog was ranked as follows.

A: There is no fog at all. ：: Fog is slightly observed, but there is no practical problem. Δ: Fog is slightly large. X: Very much fog.

[0079]

[Table 2] Table 3 shows the paddle configuration of the kneading apparatus (twin-screw extruder) used in Examples 5 to 9 or Comparative Examples 5 to 9. The kneading paddle used had the shape shown in FIGS.

[0080]

[Table 3] Example 5 100 parts of styrene-n-butyl acrylate copolymer [weight mixing ratio (low molecular weight resin: high molecular weight resin) = 75: 25, molecular weight peak values of 1.4 × 10 ⁴ and 7.2 × 10 ⁵ ] Low Molecular weight polyethylene 4 parts (melting point: 129 ° C., melt viscosity at 140 ° C .: 280 cP) Magnetic substance: 80 parts Nigrosine dye 2 parts After premixing these raw materials with a Henschel mixer, the kneading device (5) was used to raise the heating temperature to 130. ° C, the number of revolutions of the paddle is set to 120 rpm, melt-kneaded, cooled and solidified,
The kneaded product was pulverized and classified to obtain a toner having a weight average particle size of about 8 μm. To 100 parts of this toner, 0.8 part of hydrophobic colloidal silica was dry-mixed to obtain Toner 5.

FIG. 7 is a schematic view of the paddle structure of the kneading device (5).

Comparative Example 5 Comparative toner 5 was obtained in the same manner as in Example 5 except that the mixture was melted and kneaded by the comparative kneading device (4).

Example 6 100 parts of styrene-n-butyl acrylate copolymer [weight mixing ratio (low molecular weight resin: high molecular weight resin) = 70: 30 The molecular weight peak values were 1.1 × 10 ⁴ and 6.8 × 10 ⁵ ] Low molecular weight polypropylene 4 parts (melting point: 148 ° C., melt viscosity at 140 ° C .: 340 cP) Magnetic substance 90 parts Nigrosine dye 2 parts After premixing these raw materials with a Henschel mixer, heating with a kneading device (6) The temperature was set at 140 ° C and the paddle rotation speed was set at 120 rpm.
The kneaded product was pulverized and classified to obtain a toner having a weight average particle size of about 8 μm. To 100 parts of this toner, 0.6 part of hydrophobic colloidal silica was dry-mixed to obtain Toner 6.

Comparative Example 6 A comparative toner 6 was obtained in the same manner as in Example 6 except that the mixture was melted and kneaded by the comparative kneading apparatus (5).

Example 7 100 parts of styrene-n-butyl acrylate copolymer [weight mixing ratio (low molecular weight resin: high molecular weight resin) = 80: 20 The molecular weight peak values were 1.5 × 10 ⁴ and 7.6 × 10 ^{4 5} ] Low molecular weight polyethylene (same as in Example 5) 4 parts Magnetic substance 70 parts Metal complex of monoazo dye 3 parts After pre-mixing these raw materials with a Henschel mixer, the heating temperature was 130 ° C. in a kneading apparatus (7). , The rotational speed of the paddle is set to 120 rpm, melt-kneaded, cooled and solidified,
The kneaded product was pulverized and classified to obtain a toner having a weight average particle size of about 9 μm. To 100 parts of this toner, 0.8 part of hydrophobic colloidal silica and 1.8 parts of strontium titanate were dry-mixed to obtain Toner 7.

Comparative Example 7 Comparative toner 7 was obtained in the same manner as in Example 7 except that the mixture was melted and kneaded by the comparative kneading device (6).

Example 8 100 parts of styrene-n-butyl acrylate copolymer [weight mixing ratio (low molecular weight resin: high molecular weight resin) = 55: 45 The peak molecular weights of 2.1 × 10 ⁴ and 3.3 × 10 ^{4 5} ] Low molecular weight polypropylene (same as in Example 6) 4 parts Magnetic substance 90 parts Nigrosine dye 2 parts A toner 8 was obtained in the same manner as in Example 6 except that the above-mentioned raw materials were used.

Comparative Example 8 100 parts of styrene-n-butyl acrylate copolymer [weight mixing ratio (low molecular weight resin: high molecular weight resin) = 70: 30; peak values of molecular weights 9.0 × 10 ³ and 1.8 × 10 ^{3 5} ] Low molecular weight polyethylene (same as in Example 5) 4 parts Magnetic substance 80 parts Nigrosine dye 2 parts Comparative toner 8 was obtained in the same manner as in Example 5 except that the above-mentioned raw materials were used.

Example 9 A toner 9 was obtained in the same manner as in Example 5, except that the kneading was performed by the kneading device (8).

Comparative Example 9 Styrene-n-butyl acrylate copolymer 100 parts [weight mixing ratio (low molecular weight resin: high molecular weight resin) = 60: 40 The molecular weight peak values were 1.2 × 10 ⁴ and 6.5 × 10 ^{4 5} ] Low molecular weight polyethylene (same as in Example 5) 4 parts Magnetic substance 80 parts Nigrosine dye 2 parts Comparison was conducted in the same manner as in Example 5 except that the above-mentioned raw materials were melted and kneaded by the comparative kneading apparatus (4). Toner 9 was obtained.

Although the content of the polymer resin was relatively large, the offset resistance on the high temperature side was not so good because of the breaking of the polymer chains by kneading, and the fixability was also poor.

The following tests were conducted on the above toner.
Table 4 shows the results.

Fixability and Offset Resistance Test An unfixed image was obtained with a commercially available copying machine NP-1215 (manufactured by Canon Inc.) (however, Example 7 and Comparative Example 7 were reverse developed), and a temperature-variable heat roller was externally fixed. Fixing was performed using a printer, and a fixing property and an offset resistance test were performed. In addition,
This external fixing machine has a nip of 2.5 mm and a linear pressure of 0.5 kg /
cm, process speed 64 mm / sec 100
The temperature was controlled at 5 ° C. intervals in a temperature range of ２３０230 ° C. 80 g / m ² paper was used for the fixability test, and 52 g / m ² paper was used for the offset resistance test.

The fixing start temperature is set at 50 g / m ² for the fixed image.
With a load of silbon paper (Lenz cleanin)
g paper “dasper (R)” Ozu P
aper Co. Ltd.), and the temperature at which the density reduction rate before and after rubbing is less than 10% was set to a temperature at which the offset does not appear visually when the temperature was increased.

Developability (image density, fog) Test toners 5, 6, 8, 9 and comparative toners 5, 6, 8, 9 were:
Using a commercially available copying machine FC-5II (manufactured by Canon Inc.), continuous 4000 copies were made, and toner 7 and comparative toner 7 were copied.
Was evaluated for developability (image density, fog) by copying 4000 sheets using a commercially available laser beam printer LBP-8II. The image density was measured with a reflection densitometer, and fog was ranked as follows.

A: There is no fog at all. ：: Fog is slightly observed, but there is no practical problem. Δ: Fog is slightly large. X: Very much fog.

[0097]

[Table 4] Table 5 shows the paddle configuration of the kneading apparatus (twin-screw extruder) used in Examples 10 to 16 or Comparative Examples 10 to 13. The kneading paddle used had the shape shown in FIGS.

[0098]

[Table 5] Example 10 100 parts of styrene-n-butyl acrylate copolymer (Mn = 7000, Mw = 200,000) 4 parts of low molecular weight polyethylene (melting point: 129 ° C., melt viscosity at 140 ° C .: 280 cP) Magnetic material: 80 parts (bulk density) Is 0.39 g / cm ³ ) Nigrosine dye 2 parts After premixing with the above raw material Henschel mixer, the mixture is melt-kneaded in a kneading apparatus (9) at a heating temperature of 130 ° C. and a paddle rotation speed of 120 rpm. After cooling and solidifying,
The kneaded product was pulverized and classified to obtain a toner having a weight average particle size of about 8 μm. To 100 parts of this toner, 0.8 part of hydrophobic colloidal silica was dry-mixed to obtain Toner 10.

FIG. 7 is a schematic diagram showing the paddle structure of the kneading device (9).

Comparative Example 10 A comparative toner 10 was obtained in the same manner as in Example 10 except that melt kneading was performed using the comparative kneading apparatus (7).

Example 11 100 parts of styrene-n-butyl acrylate copolymer (Mn = 5800, Mw = 230,000) 4 parts of low molecular weight polypropylene (melting point: 138 ° C., melt viscosity at 140 ° C .: 180 cP) Magnetic material: 85 parts (The bulk density is 0.53 g / cm ³ ) Nigrosine dye 2 parts After pre-mixing with the above-mentioned raw material Henschel mixer, the kneading apparatus (10) is set to a heating temperature of 140 ° C. and a paddle rotation speed of 120 rpm. After melt-kneading and solidifying by cooling, this kneaded product was pulverized and classified to obtain a toner having a weight average particle size of about 8 μm. To 100 parts of this toner, 0.6 part of hydrophobic colloidal silica was dry-mixed to obtain Toner 11.

Comparative Example 11 A comparative toner 11 was obtained in the same manner as in Example 11 except that melt kneading was performed by the comparative kneading device (8).

Example 12 100 parts of styrene-n-butyl acrylate copolymer (Mn = 7400, Mw = 240,000) Low molecular weight polyethylene (the same as in Example 10) 5 parts Magnetic substance 75 parts (gas density is 0.1%). 67 g / cm ³ ) Metal complex of monoazo dye 3 parts After pre-mixing with the above-mentioned raw material Henschel mixer, melt-kneading is performed by setting the heating temperature to 140 ° C. and the number of revolutions of the paddle to 130 rpm in the kneading apparatus (11), followed by cooling. After solidification, the kneaded product was pulverized and classified to obtain a toner having a weight average particle size of about 9 μm. To 100 parts of this toner, 0.8 part of hydrophobic colloidal silica and 2.0 parts of strontium titanate were dry-mixed to obtain Toner 12.

Comparative Example 12 A comparative toner 12 was obtained in the same manner as in Example 12 except that melt kneading was performed by the comparative kneading apparatus (9).

Example 13 Toner 13 was obtained in the same manner as in Example 10, except that the bulk density of the magnetic material was 0.28 g / cm ³ .

Example 14 Toner 14 was obtained in the same manner as in Example 11, except that the bulk density of the magnetic material was 0.75 g / cm ³ .

Example 15 Toner 15 was obtained in the same manner as in Example 10 except that the bulk density of the magnetic material was 0.21 g / cm ³ .

Since the bulk density of the magnetic material was too small, the raw materials were not bite well during kneading, and it was necessary to reduce the supply amount.

Comparative Example 13 Comparative toner 13 was obtained in the same manner as in Example 11 except that the bulk density of the magnetic material was 1.5 g / cm ³ .

Example 16 A toner 16 was obtained in the same manner as in Example 10, except that the kneading was performed by the kneading device (12).

The following tests were conducted on the above toner.
Table 6 shows the results.

Developability (Image Density, Fog) Test In an environment of high temperature and high humidity (30 ° C./80%), toners 10, 11, 1
3, 14, 15 and 16 and comparative toners 10, 11 and 13 were copied continuously 4000 sheets by a commercially available copying machine FC-2 (manufactured by Canon Inc.), and toner 12 and comparative toner 12 were commercially available. 400 continuous from laser beam printer LBP-8II
Zero copies were made, and the developability (image density, fog) at the beginning and end was evaluated. The image density was measured with a reflection densitometer, and fog was ranked as follows.

A: There is no fog at all. ：: Fog is slightly observed, but there is no practical problem. Δ: Fog is slightly large. X: Very much fog.

Offset Resistance Test An unfixed image was obtained with a commercially available copying machine NP-1215 (manufactured by Canon Inc.) (however, Example 12 and Comparative Example 12 were subjected to reversal development). Then, an offset resistance test on a high temperature side was performed. The external fixing device has a nip of 3.0 mm, a linear pressure of 0.6 kg / cm, and a process speed of 64 mm / sec.
The temperature was adjusted at 5 ° C. intervals in the above temperature range.

The high-temperature offset occurrence temperature was a maximum temperature at which no offset was visually observed when the temperature was increased.

[0116]

[Table 6]

[0117]

The toner obtained by the production method of the present invention has sufficient dispersibility even when the shearing force applied to the kneaded material during kneading is small, and has a small amount of molecular chain breakage due to kneading. It has excellent fixability and anti-offset properties, and is free from image stains such as fog and contamination of the charging member, and has good developability. In addition, the dispersibility of wax, magnetic material, and the like is good. Further, even in the case of repeated production by reusing fine powder, coarse powder, and the like sorted in the classification step, a toner having a good yield and good fixability, offset resistance, and developability can be obtained.

[Brief description of the drawings]

FIG. 1 is a schematic view of a kneading apparatus suitable for the present invention.

FIG. 2 is a detailed view of a paddle in the kneading apparatus of FIG.

FIG. 3 is a schematic view showing an example of a paddle in a screw section of a kneading apparatus.

FIG. 4 is a schematic view showing an example of a paddle in a kneading section of the kneading apparatus.

FIG. 5 is a schematic view showing another example of the paddle in the kneading section of the kneading apparatus.

FIG. 6 is a schematic view showing another example of the paddle in the kneading section of the kneading apparatus.

FIG. 7 is a schematic diagram of a paddle configuration of kneading apparatuses (1), (5), and (9).

──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Hiroaki Kawakami 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc. (72) Inventor Masaji Fujiwara 3-30-2 Shimomaruko, Ota-ku, Tokyo JP-A-3-149567 (JP, A) JP-A-3-86224 (JP, A) JP-A-2-308175 (JP, A) JP-A-3-185458 (JP) JP-A-1-219768 (JP, A) JP-A-1-219759 (JP, A) JP-A-56-31433 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB G03G 9/087 G03G 9/083 B01F 7/08

Claims (3)

(57) [Claims] 1. A method for producing a toner comprising at least one kind of wax and a resin, which is obtained by mixing a solution of at least one kind of wax and a resin, and removing the solvent.
A kneading device in which a paddle is provided in the cylinder in the axial direction, the screw L / D is 23 or more, the kneading part has two or more places, and the L _n / D of all the kneading parts is 6 or less, A method for producing a toner for developing electrostatic images, comprising a step of melting and kneading toner raw materials. (However,
L paddle total length, L _n is the total kneading portion of the length, D is represents the screw diameter. ) 2. The molecular weight distribution measured by GPC is 2 × 10 ⁵
In the method for producing a toner containing at least a binder resin having at least one peak in the above region, a paddle is provided in a cylinder in an axial direction, a screw L / D is 23 or more, and a kneading portion is 2 or more. has the reason, a kneading device L _n / D of all the kneading portion is 6 or less, the production method of the toner for developing electrostatic images, which comprises a step of melt-kneading the toner raw materials. (Where, L is a paddle total length, L _n is the total kneading portion of the length,
D represents a screw diameter. ) 3. A method for producing a toner containing at least a binder resin and a magnetic substance, wherein the magnetic substance has a bulk density of 0.9 g / cm ³ or less, a paddle is provided in an axial direction in a cylinder, and a screw is provided. L / D is not less than 23, has a kneading portion or two, a kneading device L _n / D of all the kneading portion is 6 or less, characterized in that it comprises the step of melting and kneading the toner raw materials A method for producing an electrostatic image developing toner. (However, L is the total paddle length, L
_n represents the length of the whole kneading portion, and D represents the screw diameter. )