JPH0996920A - Toner for developing electrostatic charge image - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a toner excellent in fixability, anti-offsetting property and blocking resistance by incorporating a resin binder, a colorant and a lubricant having a heat absorption peak in a specified temp. range and a specified half- breadth of the heat absorption peak in measurement with DSC. SOLUTION: This toner contains a resin binder, a colorant and a lubricant having a heat absorption peak in the range of 50-130 deg.C and <=15 deg.C half-breadth of the peak in measurement with a differential scanning calorimeter(DSC). When the peak is at <50 deg.C, blocking resistance is deteriorated. When the peak is at >130 deg.C, fixability is not improved. The peak is preferably in the range of 60-120 deg.C, especially preferably 65-90 deg.C. In the case of >15 deg.C half-breadth of the peak, a problem on blocking resistance is caused. The especially pref. half-breadth is <=10 deg.C. The amt. of the lubricant added is 0.5-30 pts.wt., preferably 1-15 pts.wt., especially preferably 2-10 pts.wt. per 100 pts.wt. of the resin binder.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a toner for developing electrostatic images. More specifically, it relates to a toner for developing an electrostatic image which is excellent in fixability (low temperature fixability and fix strength) using a specific lubricant, offset resistance and blocking resistance.

[0002]

2. Description of the Related Art An electrostatic charge image developing toner causes a so-called offset phenomenon in which toner is rapidly fixed, and the toner is transferred to the surface of a fixing roller to stain a transfer material passing through a fixing step with the toner on the roller. It is necessary not to. Further, the toner should not block during storage or transportation. Such a toner is significantly deteriorated in fluidity, chargeability, etc., and can no longer function as a developer. Therefore, the binder resin, which is the main component of the toner, is required to have delicate hardness and heat melting characteristics, and the toner obtained by crushing and classifying the binder resin in which the colorant and the like are dispersed is agitated by stirring in the developing machine. It is necessary for the toner itself to exhibit good fluidity without generating fine powder upon mechanical impact, and without agglomeration, and to melt quickly at low temperature during fixing, It is necessary to show cohesiveness. It is extremely difficult to design a binder resin that satisfies all of these properties, and in particular, since fixing property and anti-offset / blocking property are contradictory properties, it is difficult to make both properties compatible.

Therefore, many proposals have heretofore been made regarding the molecular weight and the molecular weight distribution of polymers used as binder resins. For example, the number average molecular weight is 1000
A toner containing 50 to 95% by weight of a low melting point, high fluidity resin of up to 4000 has been proposed (Japanese Patent Publication No. 59-1).
No. 07360), there is still a problem in offset resistance and blocking resistance. In addition, Japanese Examined Japanese Patent Publication Sho 63-321
In Japanese Patent Laid-Open No. 80, it is proposed to use a styrene copolymer binder resin having at least one local maximum value in the molecular weight regions of 10 ³ to 8 × 10 ⁴ and 10 ⁵ to 2 × 10 ⁶ .

[0004]

However, the toner according to the above publication has not yet obtained satisfactory results in fixing property to a transfer material, particularly in achieving both fixing strength and blocking resistance. That is, according to this method, the content of the low molecular weight component must be increased in order to improve the fixing property, which causes a problem in blocking resistance. On the other hand, in order to improve the blocking resistance, it is necessary to increase the content of the high molecular weight component, which causes a problem in fixability.

[0005]

As a result of intensive studies, the present invention solves the above problems and provides a toner excellent in fixability (low temperature fixability, fix strength), offset resistance and blocking resistance. Thus, a toner satisfying the above performance has been completed. That is, the gist of the present invention is to have a binder resin, a colorant, and an endothermic peak in the range of 50 to 130 ° C. in DSC measurement, and the half-value width of the endothermic peak is 1 or less.
The toner for developing an electrostatic charge image is characterized by containing a lubricant having a temperature of 5 ° C. or lower.

Hereinafter, the present invention will be described in detail. The lubricant used in the present invention is required to have an endothermic peak in the range of 50 ° C to 130 ° C in DSC (Differential Scanning Calorimeter) measurement. If the endothermic peak is lower than 50 ° C, the blocking resistance is deteriorated, and if it is higher than 130 ° C, the fixing property is not improved. The endothermic peak in the DSC measurement is
More preferably, it is 60 ° C to 120 ° C. Particularly preferably, it is 65 ° C to 90 ° C. Further, if the half width of the endothermic peak is larger than 15 ° C., a problem occurs in blocking resistance. Particularly preferably, it is 10 ° C or lower. In the present invention, DSC7000 (manufactured by Vacuum Riko Co., Ltd.) is used to
The measurement was performed at a temperature rising rate of 10 ° C./min. As the lubricant,
Those which satisfy the above conditions and more preferably have a structure represented by the following general formula (1) are mentioned.

[0007]

Embedded image

(In the formula, R ¹ represents an alkyl group or an alkoxyl group having 10 or more carbon atoms, and R ² represents -X-COOR.
³ (X represents an alkylene group, R ³ represents an alkyl group having 10 or more carbon atoms) or an alkyl group having 10 or more carbon atoms. R ¹ is an alkyl group or an alkoxyl group, each having 10 or more, preferably 16 or more, more preferably 20 or more. The carbon number of R ¹ is preferably 40 or less. R ² is -X-COOR ³ , preferably X is

[0009]

Embedded image

Wherein n is a linear alkylene group having 6 or more and R ³ is an alkyl group having 20 or more carbon atoms. R
The carbon number of ³ is preferably 40 or less. Alternatively, R ² is an alkyl group having 10 or more carbon atoms, preferably 16 or more carbon atoms. Particularly preferred is an alkyl group having 20 or more carbon atoms. The alkyl group of R ² preferably has 40 or less carbon atoms.
When R ² is -X-COOR ³ R ¹ is an alkoxyl group (i.e. diester) is preferred. Specific examples thereof include di-n-decyl ketone, di-n-dodecyl ketone, di-n-stearyl ketone, di-n-icosyl ketone, di-n-behenyl ketone, di-n-tetracosyl ketone, and other aliphatic compounds. Ketones; fatty acid diesters such as didodecyl sebacate, distearyl sebacate, dibehenyl sebacate; stearyl laurate, behenyl laurate, stearyl stearate, behenyl stearate, myricyl stearate, stearyl behenate, behenyl behenate, behene. Examples thereof include fatty acid monoesters such as acid mycyl acid, stearyl lignocerate, behenyl lignocerate, and mycyl lignocerate. A mixture of these is also suitable, but at this time, the full width at half maximum of the endothermic peak of DSC needs to be 15 ° C or less. Among them, those having a total carbon number of 36 to 70 in the molecule are particularly preferable, and aliphatic ketones are particularly preferable among the above specific examples.

As a method of adding the lubricant to the toner, it may be dissolved or dispersed in the binder beforehand, or may be added at the same time when the colorant and the like are kneaded. As a method of adding the lubricant in advance, after dissolving or suspending the binder resin and the lubricant in an organic solvent, a method of removing the solvent by distillation under reduced pressure or adding the lubricant to the monomer in the polymerization process of the binder resin, There are methods such as polymerization.

The lubricant of the present invention is usually 0.5 to 30 parts by weight, preferably 1 to 100 parts by weight of the binder resin.
˜15 parts by weight, particularly preferably 2 to 10 parts by weight. If the amount of the lubricant is too small, it is difficult to obtain the effect of adding the lubricant, and if the amount of the lubricant is too large, the blocking resistance tends to deteriorate. These are not mixed chemically with a binder resin or the like, for example, grafted, and are simply mixed. The binder resin used in the present invention is not particularly limited, and known binder resins can be used. Examples thereof include polyester resin, epoxy resin, phenoxy resin, silicone resin, styrene resin (having 30% by weight or more of structural unit of styrene or styrene derivative), polyamide resin, urethane resin, acrylic resin and the like. Styrenic resin is preferable. Particularly preferred is a homopolymer of styrene, a copolymer of styrene and a (meth) acrylic acid ester, or a mixture thereof. Particularly preferably, the weight average molecular weight of the tetrahydrofuran-soluble component in the gel permeation chromatogram is 50,000 or more, and 5 × 1.
It is a styrene resin having a molecular weight peak of 0 ⁴ or less (preferably 2 × 10 ⁴ or less, more preferably 1 × 10 ⁴ or less) and 1 or more in the range of 1 × 10 ⁵ to 1 × 10 ⁷ . When the lubricant of the present invention is combined with the above binder resin, the fixability becomes particularly good due to a synergistic effect.

In the present invention, it is preferable that the lubricant is uniformly dissolved or dispersed in the binder resin.
Incidentally, the tetrahydrofuran insoluble matter in the present invention,
Add the binder resin or the binder resin in the toner to tetrahydrofuran so as to be 1% by weight, and
It can be defined as a component that is not filtered after 8 hours of vigorous stirring. The insoluble content is preferably 70% by weight or less, more preferably 40% by weight or less, and further preferably 25% by weight or less.

In the present invention, known ordinary methods are used to measure the weight average molecular weight and the molecular weight peak of the soluble component obtained by the above method. For example, an appropriate method in usual gel permeation chromatography is used as follows.

[0015]

[Table 1] 1. Measurement conditions Temperature: 40 ° C. Solvent: Tetrahydrofuran Flow rate: 0.5 ml / min Sample concentration: 0.1 wt% Sample injection amount: 100 μl

2. Column As a column used for appropriately measuring the molecular weight region of 1 × 10 ^{3 to} 2 × 10 ^6, a combination of a plurality of commercially available polystyrene gel columns is used. In the measurement of the present invention, GMHXL (30 cm ×, manufactured by Tosoh Corporation)
2) were used.

3. Calibration curve The calibration curve is prepared using standard polystyrene. The standard polystyrene is, for example, Pressure.
chemical Co. Manufactured by Tosoh Co., Ltd. and having a molecular weight of, for example, 6 × 10 ² , 2.8 × 10 ³ , 6.2.
^{× 10 3, 1.03 × 10 4} , 1.67 × 10 4, 4.
39 × 10 ⁴ , 1.02 × 10 ⁵ , 1.86 × 10 ⁵ ,
2.2 × 10 ⁵ , 7.75 × 10 ⁵ , 1.26 × 10 ⁶
It is appropriate to use at least about 10 standard polystyrene.

4. Detector An RI (refractive index) detector is used as the detector. As the colorant, all known ones can be used, and examples thereof include carbon black, nigrosine, benzidine yellow, quinacridone, rhodamine B, and phthalocyanine blue.

In addition to the toner of the present invention, various substances that can be added at the time of toner production can be added. The toner of the present invention can be used in both a dry one-component developer and a two-component developer, and magnetic materials used in the one-component developer include iron, cobalt, nickel and the like including ferrite and magnetite. Alloys exhibiting ferromagnetism, or alloys containing no compound or ferromagnetic element but exhibiting ferromagnetism by appropriate heat treatment, for example, manganese and copper such as manganese-copper-aluminum or manganese-copper-tin. Examples thereof include alloys of a type called Heusler alloy, including chromium, and chromium dioxide. The magnetic substance is uniformly dispersed in the binder resin in the form of fine powder having an average particle size of 0.3 to 30 μm. The content of the magnetic particles is preferably 20 to 70 parts by weight, particularly 40 to 70 parts by weight, per 100 parts by weight of the binder resin.

The charge control of the toner may be performed by the binder resin and the colorant itself, but a charge control agent may be used in combination if necessary. Use a quaternary ammonium salt, a basic / electron-donating organic substance as the positive charge control agent, and a metal chelate, a metal-containing dye, an acidic or electron-withdrawing organic substance, etc. as the negative charge control agent. You can In addition,
Inorganic particles such as metal oxides or inorganic substances surface-treated with the above organic substances may be used. These charge control agents may be mixed and added to the binder resin, or may be used in the form of being attached to the surface of the toner particles. The addition amount of the charge control agent can be determined in consideration of the chargeability of the binder resin, the manufacturing method including the addition amount / dispersion method of the colorant, and the chargeability of other additives. 100
0.1 to 10 parts by weight is suitable with respect to parts by weight.

Furthermore, a solid electrolyte, a polymer electrolyte,
The electrical properties of the toner can be controlled by adding a charge transfer complex, a conductor such as a metal oxide such as tin oxide, a semiconductor, a ferroelectric substance, a magnetic substance, or the like. In addition, various plasticizers such as low molecular weight polyalkylenes and auxiliary agents such as release agents may be added to the toner for the purpose of adjusting thermal characteristics and physical characteristics. The addition amount is 100
0.1 to 10 parts by weight is suitable with respect to parts by weight.

Further, for the toner particles, Ti
By adding fine powder such as O ₂ , Al ₂ O ₃ , and SiO ₂ and coating the surface of the toner particle with these, the fluidity and aggregation resistance of the toner can be improved. The amount added is 0.1 to 100 parts by weight of the binder resin.
10 parts by weight is preferred. Various conventionally used toner production methods can be applied to the toner production method of the present invention. For example, the following examples can be given as general production methods. First, a binder resin, a colorant, a lubricant (which may be omitted if added in advance to the binder resin), and optionally a charge control agent, etc. are ball milled, V type mixer, S type mixer,
Disperse evenly with a Henschel mixer. Then, the dispersion is melt-kneaded with a double-arm kneader, a pressure kneader or the like. The mixture is crushed by a crusher such as a hammer mill, a jet mill or a ball mill, and the obtained powder is classified by an air classifier or the like. The particle size of the toner is usually 5 to 20 μm. When the obtained toner does not contain a magnetic material, it can be mixed with a carrier to form an electrophotographic developer, and can be used for copying by a conventional electrophotographic method. As the carrier, it is preferable to use 10 to 100 parts by weight of a known magnetic substance such as iron powder type carrier, ferrite type carrier or the like, or a material having a coating on the surface thereof per 1 part by weight of the toner.

[0023]

EXAMPLES Hereinafter, specific examples of the present invention will be described, but the present invention is not limited to these examples. In addition, "part" in an Example represents a "weight part." Example 1 Cross-linking type styrene / n-butyl acrylate resin (composition 80/20 weight ratio, insoluble matter 30 wt% in tetrahydrofuran, soluble matter molecular weight distribution: 7.
100 parts of resin having a weight average molecular weight of 8 × 10 ⁴ having peaks at 0 × 10 ³ and 2.0 × 10 ⁵ , distearyl ketone (endothermic peak in DSC 87.5 ° C., full width at half maximum 6 ° C.)
5 parts, polyalkylene wax (manufactured by Sanyo Kasei Co., Ltd., Viscole 550P) 3 parts, carbon black (Mitsubishi Kasei Co., Ltd. # 30) 6 parts, Nigrosine dye (Orient Chemical Co., Bontron N-04) 2 parts After dispersing and mixing
Melt kneading was performed using a twin screw extruder. After cooling, it was roughly crushed with a hammer mill and then finely crushed with a supersonic jet mill crusher. The obtained powder was classified by an air classifier to obtain a toner A having an average particle size of 10.3 μm. The following tests were conducted using this toner.

Fixing test: 400 mm of unfixed toner
The paper was passed through a fixing roller of / sec and the lower limit temperature for fixing and the temperature at which hot offset occurred were examined. Rubbing residual rate test: After passing unfixed toner having various amounts of adhesion through a fixing roller at 135 ° C. and 400 mm / sec, a rubbing test was performed. The rubbing residual rate was obtained from the following formula, and the minimum value was defined as the minimum rubbing residual rate.

[0025]

[Equation 1]

Blocking resistance test: After applying a constant load to the toner and leaving it in an environment of 50 ° C. for 5 hours, the presence or absence of aggregation was visually confirmed to judge the blocking property. The results are shown in Table 1.

Example 2 Non-crosslinked styrene / stearyl acrylate resin (the molecular weight distribution has two peaks, the low molecular weight peak is 4500, and the high molecular weight peak is 6.5 × 10 ^5). And low molecular weight side / high molecular weight side = 75
It is composed of a weight ratio of / 25. Weight average molecular weight 1.
7 × 10 ⁵ ) Toner B was produced and evaluated in the same manner as in Example 1 except that 100 parts were used.

Example 3 Toner C was used in the same manner as in Example 1 except that 5 parts of sebacic acid distearyl ester (endothermic peak in DSC, 70.5 ° C., full width at half maximum 6 ° C.) was used in place of distearyl ketone.
Was manufactured and evaluated. Example 4 Example 1 was repeated, except that 5 parts of Unistar M-2222SL (behenyl behenate, endothermic peak in DSC, 76.0 ° C, full width at half maximum 8 ° C) manufactured by NOF CORPORATION was used in place of distearyl ketone. Toner D was manufactured and evaluated in the same manner as in.

Example 5 In place of the distearyl ketone, 5 parts of Kawawax L (G) manufactured by Kawaken Fine Chemical Co., Ltd. (main component is myrisyl lignocerate, endothermic peak in DSC: 86 ° C., half-value width: 5 ° C.) was used. Toner E is the same as in Example 1 except that
Was manufactured and evaluated.

Example 6 70 parts of polystyrene having a molecular weight peak of 5000 and styrene / stearyl acrylate having a molecular weight peak of 7.5 × 10 ⁵ = 90/10 (weight ratio) Copolymer (weight average molecular weight 2.3 × 10 ⁵ ) 30 Part, Kao Wax T made by Kao
-1 (Distearyl ketone, endothermic peak 8 by DSC
(7.5 ° C., full width at half maximum 8 ° C.) 5 parts were dissolved in tetrahydrofuran, poured into water and the precipitate was taken out by decanting.
A binder resin was obtained by vacuum drying at ° C. Toner F was produced in the same manner as in Example 1 except that this was used.
An evaluation was performed.

Example 7 75 parts of styrene was polymerized in xylene using benzoyl peroxide as a polymerization initiator to give a molecular weight peak of 8000.
A styrene homopolymer of Then, in the above polymer solution, behenyl behenate (endothermic peak 7 by DSC
Then, 25 parts of styrene / n-butyl acrylate = 80/20 copolymer having a molecular weight peak of 6.5 × 10 ⁵ synthesized by emulsion polymerization (5 parts, 6.0 ° C., half-width: 8 ° C.) was added and completely dissolved. Then, xylene was distilled off, and a styrene resin in which a lubricant was uniformly dissolved (weight average molecular weight 1.7 × 1
0 ⁵ ) was obtained. After roughly crushing to about 0.5 mm, toner G was manufactured and evaluated in the same manner as in Example 1.

Comparative Example 1 Toner H was produced and evaluated in the same manner as in Example 1 except that 5 parts of distearyl ketone was not added. Comparative Example 2 Toner I was produced in the same manner as in Example 1 except that a lubricant (ethylene bisstearic acid amide) having an endothermic peak at 141.5 ° C. and a full width at half maximum of 10 ° C. was used in DSC measurement. I did.

Comparative Example 3 Toner J was produced in the same manner as in Example 1 except that a lubricant (hardened castor oil) having an endothermic peak at 85.0 ° C. and a half-value width of 24.8 ° C. was used in DSC measurement. , Evaluated. Comparative Example 4 Lubricant (low molecular weight polyethylene) having an endothermic peak at 135.0 ° C and a half width of 11.0 ° C in DSC measurement
Toner K was manufactured and evaluated in the same manner as in Example 1 except that was used.

[0034]

[Table 2] Blocking resistance: ○ No aggregation × Aggregation

As is clear from Table 1, the toner of the present invention was excellent in fixability (low temperature fixability, fix strength), offset resistance and blocking resistance.

[0036]

According to the present invention, low temperature fixability, fix strength,
A toner excellent in offset resistance and blocking resistance can be obtained.

Claims (4)

[Claims] 1. A binder resin, a colorant, and a DSC.
A toner for developing an electrostatic charge image, which comprises a lubricant having an endothermic peak in the range of 50 to 130 ° C. in measurement and having a half-value width of the endothermic peak of 15 ° C. or less. 2. The lubricant is represented by the general formula (1): (In the formula, R ¹ represents an alkyl group or an alkoxyl group having 10 or more carbon atoms, and R ² represents -X-COOR ³ (X represents an alkylene group, and R ³ represents an alkyl group having 10 or more carbon atoms.) Or an alkyl group having 10 or more carbon atoms.)
The toner for developing an electrostatic charge image according to claim 1, having a structure represented by: 3. The binder resin has a weight average molecular weight of 50,000 or more in a gel permeation chromatogram of a tetrahydrofuran-soluble component and is in the range of 1 × 10 ⁴ to 1 × 10 ⁵ to 1 × 10 ⁷ . The toner for developing an electrostatic charge image according to claim 1 or 2, which is a styrene-based resin having one or more molecular weight peaks. 4. The toner for developing an electrostatic charge image according to claim 1, wherein the content of the lubricant is 0.5 to 30 parts by weight with respect to 100 parts by weight of the binder resin.