JPH0810346B2 - Toner for electrostatic image development - Google Patents

Description

The present invention relates to a toner for developing an electrostatic charge image in electrophotography, electrostatic recording, electrostatic printing and the like.

[Prior Art] Conventionally, as an electrophotographic method, many methods are known as described in US Pat. No. 2,297,691, Japanese Patent Publication No. 42-23910 and Japanese Patent Publication No. 43-24748. Generally, a photoconductive substance is used to form an electrical latent image on a photoconductor by various means, and then the latent image is developed with toner, and a transfer material such as paper is used as necessary. After the toner image is transferred to, the toner image is fixed by heating, pressure or solvent vapor to obtain a copy.

Various methods and devices have been developed for the final step of fixing the toner image on a sheet such as paper. The most popular method at present is a pressure heating method using a heating roller.

The pressure heating method using a heating roller performs fixing by allowing the toner image surface of the sheet to be fixed to pass under pressure while contacting the surface of a heating roller whose surface is formed of a material having releasability for toner. Is. In this method, since the surface of the heat roller and the toner image on the sheet to be fixed are brought into contact with each other under pressure, the thermal efficiency at the time of fusing the toner image on the sheet to be fixed is extremely good, and rapid fixing is possible. It is possible and very effective in a high speed electrophotographic copying machine. However, in the above method, since the heat roller surface and the toner image are in contact with each other in a molten state under pressure, a part of the toner image adheres to and transfers to the fixing roller surface, and re-transfers to the next sheet to be fixed. A so-called offset phenomenon may occur and the sheet to be fixed may be soiled. Preventing toner from adhering to the surface of the heat fixing roller is one of the essential conditions of the heat roller fixing method.

As described in JP-B-51-23354, such an offset phenomenon tends to occur when a low molecular weight resin is used. Therefore, it is thought that the offset phenomenon can be prevented by using a crosslinked resin as described in the same publication, but even if the degree of crosslinking is simply increased, the fixing temperature becomes high, and in the case of a magnetic toner, However, since the fixing temperature rises and the offset resistance deteriorates, there are many problems.

Further, for the purpose of not adhering the toner to the surface of the fixing roller, for example, the roller surface is formed of a material excellent in releasability from the toner, such as silicon rubber or fluorine resin,
Further, in order to prevent offset and prevent fatigue of the roller surface, the roller surface is coated with a thin film of a liquid having a good releasability such as silicone oil. However, this method is extremely effective in preventing toner offset, but the offset preventing liquid evaporates by heating to give a user an unpleasant odor and a device for supplying the offset preventing liquid is required. Therefore, there is a problem that the fixing device becomes complicated. Therefore, it is not preferable that the offset is prevented by supplying the offset preventing liquid. Rather, it is desired to develop a toner having a wide fixing temperature range and high anti-offset properties.

Further, in the case of an apparatus having a transfer step, the residual toner on the photoconductor that has not been transferred to the transfer sheet is removed,
It is usual to repeatedly use the photoreceptor. As a method for removing the residual toner on the photoconductor, a cleaning member is generally brought into contact with the photoconductor such as a blade cleaning system, a fur brush cleaning system, or a magnetic brush cleaning system.

In this case, since the cleaning member is pressed against the photoconductor with an appropriate pressure, the photoconductor may be scratched or the toner may be fixed during repeated use. When cleaning failure occurs, the obtained image is contaminated in spots or stripes, which is considered to be impractical.

It is known to add a friction reducing substance to the toner in order to avoid the phenomenon that the toner is fused to the photoreceptor. However, this method is effective in preventing cleaning failure such as toner adhesion phenomenon, but has the following problems. That is, in the conventionally known friction-reducing substance, a large amount of it has to be added in order to exert an effect under poor cleaning conditions of low temperature and low humidity. Makes it difficult to remove low electric resistance substances such as paper powder and ozone adducts that are generated or adhered to the surface of the photoconductor, and the latent image on the photoconductor is a low electric resistance substance especially in an environment of high temperature and high humidity. There is a problem that it is significantly impaired by.

Also, toners require various physical and chemical properties. In particular, in the demand for high functionality and high reliability of copiers, as toners, toners with excellent low-temperature fixability capable of coping with high-speed copiers, and toners with high durability and high productivity Is desired.

There is a method of using a binder resin having a low molecular weight and a low melting point in order to obtain a toner having good low-temperature fixability. However, this type of binder resin does not have sufficient mechanical strength on the surface of the toner, and is likely to cause deterioration of the toner during use and contamination of the photoreceptor, cleaner, fixing device, and the like.

[Problems to be Solved by the Invention] Therefore, an object of the present invention is to provide a toner having excellent physical and chemical properties, which overcomes the above-mentioned defects of the toner.

An object of the present invention is to provide a toner having good low-temperature fixability and anti-offset property, and having no toner or paper powder or other such adhered matter on the surface of the photoreceptor.

Further, an object of the present invention is to provide a toner for fixing on a heat roller, which has a good chargeability and always shows a stable chargeability during use, and which gives a clear and fog-free image.

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

Further, the object of the present invention is to provide a magnetic developer,
The present invention provides a magnetic toner that exhibits good and uniform magnetism and can be fixed on a heat roller.

[Means and Actions for Solving Problems] Specifically, the present invention relates to an electrostatic charge image developing toner containing a styrene-based binder resin, which comprises an addition-polymerizable carboxylic acid in the styrene-based binder resin. The content of the unit and / or the addition-polymerizable carboxylic acid ester unit is 10 to 40 mol in the range of the molecular weight of 10 ^{3 to} 5 × 10 ^4.
%, And 0 to 10mo in the region of molecular weight 5 × 10 ⁴ to 10 ^6.
It is 1% (excluding the case where the molecular weight distribution of the styrene-based binder resin has at least two peaks), and relates to an electrostatic charge image developing toner.

In the present invention, the molecular weight distribution of the polymer is 10 ^{3 to} 5 × 1.
By controlling the content of the addition-polymerizable carboxylic acid unit and / or the carboxylic acid ester unit in the polymer composition in the range of 0 ^{4 and} the range of 5 × 10 ⁴ to 10 ⁶ , the above-mentioned object can be achieved. is there. That is, in order to improve the low-temperature fixability, it is necessary to lower the melting point and improve the melt fluidity of the binder resin of the toner. For this reason, there is a method of lowering the melting point by increasing the glass transition point and the flow starting point by a flow tester by increasing the acrylic component in the binder resin, but it is inferior in developability, and the photoreceptor, developing sleeve, cleaning blade To be easily adhered.

On the other hand, in the present invention, the above problems are overcome by reducing the content of the addition-polymerizable carboxylic acid unit and / or the addition-polymerizable carboxylic acid ester unit on the high molecular weight side. That is, the above content is a molecular weight of 10 ³ ~
10 to 40 mol%, preferably 10 to 25 in the area of 5 × 10 ^4.
0 to 10 mol in the region of mol% and molecular weight 5 × 10 ⁴ to 10 ⁶
It should be%. That is, it was found that by further increasing the styrene component on the high molecular weight side, the amount of charge that can be taken as a toner is increased, and the developability is improved. It has been found that the adhesion is less likely to occur and that the adhesion is effectively polished from the surface of the photoreceptor. Further, in the binder resin constitution of the present invention, the high molecular weight component is thermally stabilized and further imparts strength, so that it is also excellent in blocking resistance and impact resistance.

As described above, according to the present invention, it is possible to obtain a toner having a good low-temperature fixing property and to solve the drawbacks of the conventional low-temperature fixing toner, such as the deterioration of the developing property and the contamination of the photoconductor.

As the polymerizable monomer applicable to the present invention, styrene, o-methylstyrene, m-methylstyrene, p-methylstyrene, p-methoxystyrene, p-phenylstyrene, p-
Chlorostyrene, 3,4-dichlorostyrene, p-ethylstyrene, 2,4-dimethylstyrene, pn-butylstyrene, p-
At least one selected from styrene and its derivatives such as tert-butyl styrene, pn-hexyl styrene, pn-octyl styrene, pn-nonyl styrene, pn-decyl styrene, pn-dodecyl styrene; and methacrylic acid, methyl methacrylate, methacrylic acid. Ethyl, propyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, n-octyl methacrylate, dodecyl methacrylate, 2-ethylhexyl methacrylate, stearyl methacrylate, phenyl methacrylate, dimethylaminoethyl methacrylate, methacryl Acid diethylaminoethyl, acrylic acid, methyl acrylate, ethyl acrylate, -n-butyl acrylate, isobutyl acrylate,
Propyl acrylate, acrylate-n-octyl acrylate, dodecyl acrylate, 2-ethylhexyl acrylate, stearyl acrylate, 2-chloroethyl acrylate,
At least one selected from carboxylic acids having a double bond and esters thereof such as phenyl acrylate, dibutyl maleate, dimethyl maleate, etc .; and, if necessary, other monomers such as ethylene, propylene, butylene, isobutylene, etc. Ethylenically unsaturated monoolefins; vinyl halides such as vinyl chloride, vinylidene chloride, vinyl bromide, vinyl fluoride; vinyl esters such as vinyl acetate, vinyl propionate, vinyl benzoate; vinyl methyl ether, vinyl acetate Ruether,
Vinyl ethers such as vinyl isobutyl ether; vinyl ketones such as vinyl methyl ketone, vinyl hexyl ketone and methyl isopropenyl ketone; N-vinyl pyrrole, N-vinyl carbazole, N-vinyl indole, N-
N-vinyl compounds such as vinylpyrrolidone; vinylnaphthalenes; vinyl monomers such as acrylic acid or methacrylic acid derivatives such as acrylonitrile, methacrylonitrile, amrylamide and the like are used in appropriate combination.

As the method for producing the polymer of the present invention, it can be synthesized by using a known polymerization means such as solution polymerization, suspension polymerization, emulsion polymerization, bulk polymerization and the like. As a process for synthesizing the polymer for binder, solution polymerization, suspension polymerization, and emulsion polymerization are preferable in controlling the degree of polymerization, molecular weight, and molecular weight distribution. Further, the composition distribution can be set to a desired one by a method of carrying out the polymerization in two stages, a method of changing a monomer charging ratio during the polymerization, a polymerization temperature and the like. The content of the addition-polymerizable carboxylic acid unit and the addition-polymerizable carboxylic acid ester unit is mainly controlled by the monomer charging ratio.

In order to use the toner as a magnetic toner, magnetic powder may be contained. As such magnetic powder, a substance that is magnetized by being placed in a magnetic field is used, and there are powders of ferromagnetic metals such as iron, cobalt and nickel, or alloys and compounds such as magnetite, hematite and ferrite. The content of this magnetic powder is 15 to 70 relative to the toner weight.
Weight% is good.

In the toner, if necessary, a charge control agent, a coloring agent,
A fluidity modifier may be added, and the charge control agent and the fluidity modifier may be mixed (externally added) with the toner particles and used. Examples of the charge control agent include metal-containing dyes and nigrosine, and conventionally known dyes and pigments can be used as the colorant. Colloidal silica, fatty acid metal salts and the like can be used as the fluidity modifier. There is. In addition, for the purpose of increasing the amount, 0.5 to 20 wt% of filler such as calcium carbonate or fine powder silica is added.
It can be blended in the toner within the range of%. Further, in order to prevent the mutual aggregation of the toner particles and improve the fluidity thereof, a fluidity improver such as Teflon fine powder may be added, and for the purpose of improving the releasability at the time of heat roll fixing. Wax-like substances such as low molecular weight polyethylene, low molecular weight polypropylene, microcrystalline wax, carnauba wax, and sazol wax can be added in an amount of about 0.5 to 5 wt%.

If necessary, a colorant may be added to the toner of the present invention, and a well-known pigment or dye can be used as the colorant.

Colorants include carbon black, nigrosine dye, lamp black, Sudan Black SM, First Yellow G, Benzidine, Yellow, Pigment Yellow, India First Orange, Irgadine Red, Baranitroaniline Red, Toluidine Red. , Carmine FB, Permanent Bordeaux FRR, Pigment Orange R, Resor Red 2G, Lake Red C, Rhodamine FB, Rhodamine B Lake, Methyl Violet B Lake, Phthalocyanine Blue, Pigment Blue,
Brilliant Green B, Phthalocyanine Green,
Oil Yellow GG, Zapon First Yellow CGG, Kayaset Y963, Kayaset YG, Sumiplast Yellow G
G, Zapon Fast Orange RR, Oil Scarlet, Sumiplast Orange G, Orazol Brown B, Zapon Fast Scarlet CG, Eisenspiron Red BEH, Oil Pink OP, CI Direct Red 1, CI Direct Red 4, CI Acid Red 1, CI Basic Red 1, CI Modant Red 3
0, CI Direct Blue 1, CI Direct Blue 2, CI Acid Blue 9, CI Acid Blue 15, C.
I. Basic Blue 3, CI Basic Blue 5, CI
Modant Blue 7, CI Direct Green 6, CI
Basic Green 4, CI Basic Green 6, Yellow Lead, Cadmium Yellow, Mineral Fast Yellow,
Navel Yellow, Naphthol Yellow S, Hansa Yellow G, Permanent Yellow NCG, Tartrazine Lake, Red Mouth Lead, Molybdenum Orange, Permanent Orange GTR, Pyrazolone Orange, Benzidine Orange G, Cadmium Red, Permanent Red 4R, Watching Red Calcium Salt, Eosin. Lake, Brilliant Carmine 3B, Manganese Purple, Fast Violet B, Navy Blue, Cobalt Blue, Alkali Blue Lake, Victoria Blue Lake, Fast Sky Blue, Indanthrene Blue BC, Chrome Green, Chrome Oxide, Pigment Green B, Malachite Green Lake, Final Yellow Green G etc.

The molecular weight distribution and composition distribution of the polymer of the present invention were measured as follows.

Gel permeation chromatography (GP
According to C), a temperature of 40 ° C., a solvent of tetrohydrofuran, a measurement flow rate of 1.0 ml / min, a concentration of 0.1 wt% and 300 μl of THF are injected.
A calibration curve prepared from a monodisperse polystyrene standard sample is used for measuring the molecular weight of the sample. Although the column is not limited to this, there is, for example, A-80M manufactured by Showdex.

There are various methods for the composition distribution. Here, a thin layer chromatography method (TLC) is used, and a method in which a sample separated by molecular weight classification by the above GPC and fractionated is measured by TLC.

[Examples] Production examples of polymers are shown below.

Production Example I 40 parts by weight of toluene was placed in a three-necked flask, 90 parts by weight of styrene, 10 parts by weight of butyl acrylate, and 0.6 parts by weight of divinylbenzene were added, and the gas phase was replaced with nitrogen gas, and then maintained at 80 ° C A solution prepared by dissolving 0.2 parts by weight of benzoyl peroxide in 10 parts by weight of toluene was added dropwise over 30 minutes by using a dropping funnel which was replaced with nitrogen gas, and the mixture was further added for 80 hours.
Stir at ℃. Then, 5 parts by weight of a toluene solution containing 30 parts by weight of butyl acrylate and 0.2 parts by weight of benzoyl peroxide was added dropwise, 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, the precipitate was separated, dried at 60 ° C. and recovered.
This polymer has a melt index of 1.7 g / 10 minutes and a butyl acrylate content of 16 mol at a molecular weight of 10 ^{3 to} 5 × 10 ⁴ .
%, The molecular weight was 5 × 10 ⁴ to 10 ^{6 and} was 4 mol%.

Production Example II Production Example II was repeated except that 95 parts by weight of styrene, 5 parts by weight of methyl methacrylate and 0.6 parts by weight of divinylbenzene were used as monomers, and then 30 parts by weight of methyl methacrylate were used. This polymer has a melt index of 3.0 g / 10 minutes, a methyl methacrylate content of 24 mol% at a molecular weight of 10 ^{3 to} 5 × 10 ⁴ , and a molar ratio of 5 mol at a molecular weight of 5 × 10 ⁴ to 10 ⁶ .
It was l%.

 Hereinafter, the present invention will be described with reference to examples.

Example 1 100 parts by weight of the polymer synthesized in Preparation Example I, nigrosine 3
Parts by weight, 60 parts by weight of magnetic powder (Fe ₃ O _{4 having} an average particle size of 0.3 μm),
2 parts by weight of polyethylene was kneaded using a roll mill at a temperature of 150 ° C. for 30 minutes. After cooling, the powder was finely pulverized with an air jet type pulverizer, and particles having a particle size of 5 to 20 μm were selected with an air classifier to obtain a toner. To 100 parts by weight of this toner, 0.5 part by weight of hydrophobic colloidal silica was externally added to obtain a toner for developing an electrostatic image.

The above electrostatic image developing toner was applied to a commercial copying machine NP-3525 (manufactured by Canon Inc.). The fixing temperature of the electrostatic image developing toner is 140 ° C., and the offset phenomenon is the fixing temperature.
Not observed from 40 ° C to 210 ° C.

Further, the temperature of the fixing roller was set to 160 ° C., and a durability test was conducted on 30,000 sheets. The image density was as high as 1.34 to 1.37, including the time of replenishing the toner, and a good image without fog was obtained. Further, even after 30,000 sheets, there was no offset phenomenon to the fixing roller, and there were no problems such as scratches on the surface of the photosensitive drum, cleaning blade, developing sleeve and the like, fusion of toner and aggregation in the developing device.

Example 2 A toner for developing an electrostatic charge image was obtained in the same manner as in Example 1 except that the polymer synthesized in Production Example II was used.

When tested in the same manner as in Example 1, the fixing temperature was 135 ° C. and the density was 1.32 to 1.34 in the 30,000-sheet durability test.
It was high, and neither roller stain nor image contamination due to offset phenomenon was observed. In addition, adhesion of toner, paper dust, etc. to the photoconductor was not observed.

Comparative Example 1 In Production Example I, 75 parts by weight of styrene, 20 parts by weight of butyl acrylate, 0.8 parts by weight of divinylbenzene, benzoyl peroxide.
Polymer III was prepared in the same manner as in Preparation Example I except that the reaction in the first step was continued by using 0.6 part by weight for 6 hours.
I got The melt index of this polymer was 2.1 g / 10 minutes, and the butyl acrylate content was 9 mol% at a molecular weight of 10 ^{3 to} 5 × 10 ⁴ , and 12 mol% at a molecular weight of 5 × 10 ⁴ to 10 ⁶ .

Using Polymer III, a toner for developing an electrostatic charge image was obtained in the same manner as in Example 1. When the same test as in Example 1 was carried out, the image density was low at 1.15 to 1.21, and by the 30,000-sheet durability test, adhering substances such as toner and paper powder were found on the photosensitive member, resulting in image contamination. . Furthermore, offset was observed under high temperature conditions of 175-210 ℃.

[Effects of the Invention] As described above, according to the present invention, an electrostatic charge image having good low-temperature fixability and anti-offset properties, no deposits on the surface of the photoconductor, and other excellent physical and chemical properties. A developing toner is provided.

Claims (1)

[Claims] 1. A toner for developing an electrostatic charge image containing a styrene-based binder resin, wherein the content of the addition-polymerizable carboxylic acid unit and / or the addition-polymerizable carboxylic acid ester unit in the styrene-based binder resin is molecular weight 10 ³ ~5 × 10 10~40mol% in ⁴ regions
And 0 to 10 mol in the molecular weight range of 5 × 10 ⁴ to 10 ⁶
% (Excluding the case where the styrene-based binder resin has at least two peaks in the molecular weight distribution).