JPH0486743A - Image forming method - Google Patents

Abstract

PURPOSE:To enhance low temperature fixability and offset resistance and to prevent abrasion of a photosensitive body and unsharpening of an image by developing an electrostatic latent image formed on the amorphous silicon photosensitive layer of a photosensitive body with a toner using a specified block or graft copolymer as a binder resin. CONSTITUTION:The electrostatic latent image formed on the photosensitive body 1 provided with the amorphous silicon photosensitive layer 4 is developed with the toner using as the binder resin the block or graft copolymer obtained by chemically combining 3 - 50 pts.wt. of a crystalline polyester with 97 - 50 pts.wt. of an ion-crossinked amorphous vinyl polymer and this binder resin has a chloroform-insoluble fraction of 3 - 10 wt.%, thus permitting lower temperature fixability and offset resistance to be both enhanced, abrasion of a photosensitive body to be effectively prevented, and sharp good images to be formed stably in a large number of times without unsharpening images.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an image forming method applied to electrophotography, electrostatic printing, electrostatic recording, and the like.

[Conventional technology]

In an example of electrophotography, an electrostatic image is formed on a photoreceptor having a photoconductive photosensitive layer by charging and exposing to light, and this electrostatic image is developed with toner, and the resulting toner image is usually After being transferred to transfer paper or the like, it is fixed to form a visible image. On the other hand, residual toner remaining on the photoreceptor without being transferred is cleaned by a cleaning device.

As the toner image fixing means, a heat roller fixing method is preferably used because it has high thermal efficiency and can perform high-speed fixing.

Therefore, in order to form a good fixed image using this hot roller fixing method, a toner that has excellent low-temperature fixability and offset resistance is required.

Therefore, conventionally, the following techniques have been proposed.

■ A method of using a selenium semiconductor in the photoreceptor in a toner in which the binder resin is a block copolymer or graft copolymer formed by chemically bonding a crystalline polyester and an ionically crosslinked amorphous vinyl polymer (Unexamined Japanese Patent Publication No. 1-16375
Publication No. 5).

■ In a toner using the same binder resin as in ■ above,
A method using an organic photoconductive semiconductor (OPC) as a photoreceptor (
JP-A-1-163756).

■ Crystalline polymer with melting point Tm of 50 to 120°C 0.5
~50% by weight and 99.5~50% by weight of a non-grade polymer with a glass transition point Tg of 50~80°C as a binder resin, and an organic photoconductive semiconductor (OP).
A method of combining a photoreceptor consisting of C) (JP-A-64-3
5454).

■ A method of forming images using small-diameter toner and a photoreceptor equipped with an amorphous silicon photosensitive layer (Japanese Patent Laid-Open No. 63-1
Publication No. 3054).

(2) A method of forming an image using an aliphatic polyester toner and a photoreceptor having an amorphous silicon photosensitive layer (Japanese Patent Laid-Open No. 1-204064).

[The problem that the invention attempts to solve]

However, in the above technologies ① to ②, (1) low temperature fixing properties, (2) anti-offset properties, (3) prevention of photoreceptor scratches, and (4) prevention of image blurring, It is still difficult to obtain fully satisfactory toners.

In other words, in the above technology (1), the binder resin of the toner has a high elastic modulus and viscosity, which inhibits low-temperature fixing properties, and the toner is required to have negative chargeability, or it contains polyester, so it has a high elasticity and viscosity. There is a problem in that the electrification becomes uneven, causing streaks that look like brush strokes to appear on the image, resulting in poor images.

In addition to inhibiting low-temperature fixing properties,
When a photoreceptor is used in a high-temperature, high-humidity environment (temperature: 33°C, relative humidity: 80%), moisture in the atmosphere may adhere to the photoreceptor, causing image blurring due to ozone deterioration on the surface of the photoreceptor. There is a problem that causes image defects.

In the technology (2) above, since the photoconductor has an amorphous silicon photoconductor layer, the surface hardness is usually higher than that of an OPC photoconductor, or scratches may occur on the surface due to scraping of residual toner after transfer with a cleaning blade. There's a problem.

In the technology (2) above, the resin structure is softened, and the occurrence of scratches on the photoreceptor is slightly suppressed, and the Bossester resin has a hydrophilic group at the end, so it easily absorbs moisture, and the amorphous soric photosensitive layer Since it is sensitive to humidity, there may be problems with image blurring.

Therefore, an object of the present invention is to provide an image forming method that is fully satisfactory in all aspects of (1) low-temperature fixability, (2) offset resistance, (3) prevention of photoreceptor scratches, and (4) prevention of image blurring. It is about providing.

[Means to solve the problem]

In order to achieve the above object, the present inventors have conducted intensive research and found that 3 to 50 parts by weight of crystalline polyester and 97 to 50 parts by weight of ionically crosslinked amorphous vinyl polymer are chemically bonded. By combining a toner with a block copolymer or graft copolymer as a binder resin and a photoreceptor having an amorphous silicon photosensitive layer, (
We have completed the present invention by discovering that the following properties are fully satisfied: 1) low-temperature fixing properties, (2) anti-offset properties, (3) prevention of photoreceptor scratches, and (4) prevention of image blurring. It is something.

Therefore, in the image forming method of the present invention, an electrostatic image formed on a photoreceptor having an amorphous silicon photosensitive layer is made of 3 to 50 parts by weight of crystalline polyester and 97 to 50 parts by weight of ionically crosslinked amorphous vinyl polymer. The invention is characterized in that development is carried out using a toner whose binder resin is a block copolymer or graft copolymer in which these are chemically bonded.

Further, the binder resin of the toner is characterized in that the chloroform insoluble portion is 3% by weight or more and 10% by weight or less.

In this way, in the present invention, by using a specific copolymer as the binder resin of the toner, the requirements for low-temperature fixing properties and anti-offset properties are satisfied, and this toner is combined with a photoconductor having an amorphous silicon photoconductor layer. The combination satisfies the requirements for preventing photoreceptor scratches and preventing image blurring.

In addition, the chloroform-insoluble content in a specific copolymer was
By limiting the amount to IO weight % or more, the minimum fixable temperature is stably ensured, and as a result, the fixable temperature range is widened.

Therefore, according to the image forming method of the present invention, generation of offset toner can be effectively prevented, excellent low-temperature fixing properties can be exhibited, and good leaning can be achieved without causing scratches on the photoconductor, and image blur can be prevented. No good images can be formed.

Hereinafter, the configuration of the present invention will be specifically explained.

The specific copolymer used as the binder resin of the toner is a block copolymer or a graft copolymer formed by chemically bonding 3 to 50 parts by weight of a crystalline polyester and 97 to 50 parts by weight of an ionically crosslinked amorphous vinyl polymer. It is a copolymer.

If the blending ratio of the crystalline polyester and the ionically crosslinked amorphous vinyl polymer is within the above range, the low temperature fixability can be improved without impairing the offset resistance.

However, if the proportion of crystalline polyester is too small and the proportion of amorphous vinyl polymer is too large, low-temperature fixability deteriorates.

On the other hand, if the proportion of crystalline polyester is too high and the proportion of amorphous vinyl polymer is too low, the offset resistance will decrease.

The ionically crosslinked amorphous vinyl polymer for forming a specific copolymer must have a functional group for forming a block copolymer or a graft copolymer with the crystalline polyester. Preferred examples of such functional groups include carboxyl groups, hydroxyl groups, amino groups, and epoxy groups.

Monomers having such functional groups include acrylic acid, β
, β-dimethylacrylic acid, α-ethyl acrylic acid, methacrylic acid, fumaric acid, itaconic acid, maleic acid, crotonic acid, hydroxyethyl methacrylate, succinic acid monoacryloyloxyethyl ester, N-hydroxyethylacrylamide, N-methylolacrylamide , p-aminostyrene, glycidyl methacrylate, and the like. The monomer having such a functional group is contained in the monomer composition for obtaining the ionically crosslinked amorphous vinyl polymer in an amount of 0.1 to 20 mol%, preferably 0.5 to 20 mol%.
Preferably, it is used in a proportion of 10 mol%.

Examples of the vinyl polymer as the backbone of the ionically crosslinked amorphous vinyl polymer include polystyrene, polymethacrylate, polymethyl acrylate, polyvinyl chloride, polyvinyl acetate, polyacrylonitrile, and the like. Among these, a vinyl polymer obtained using at least one selected from styrene monomers, acrylic monomers, and methacrylic monomers as an essential component is preferred.

Styrenic monomers for obtaining vinyl polymers include:
Styrene, 0-methylstyrene, m-methylstyrene,
p-Methylstyrene, α-methylstyrene, p-ethylstyrene, 2,3-dimethylstyrene, 2,4-dimethylstyrene, p-n butylstyrene, p-t-butylstyrene, pn-hexylstyrene, p- n-octylstyrene, p-n-nonylstyrene, p-n-decylstyrene, p-n-dodecylstyrene, p-methoxystyrene, p-phenylstyrene, p-chlorostyrene, 3.
Examples include 4-dichlorostyrene. These monomers may be used alone or in combination.

Acrylic monomers for obtaining vinyl polymers include:
Acrylic acid, methyl acrylate, ethyl acrylate, butyl acrylate, isobutyl acrylate, propyl acrylate, octyl acrylate, dodecyl acrylate, lauryl acrylate, 2-ethylhexyl acrylate,
Examples include stearyl acrylate, 2-chloroethyl acrylate, phenyl acrylate, and methyl α-chloroacrylate. In addition, methacrylic acid monomers include methacrylic acid, methyl methacrylate, ethyl methacrylate, propyl methacrylate, butyl methacrylate, isobutyl methacrylate, octyl methacrylate,
Examples include methacrylic acid esters such as dodecyl methacrylate, lauryl methacrylate, 2-ethylhexyl methacrylate, stearyl methacrylate, phenyl methacrylate, dimethylaminoethyl methacrylate, and diethylaminoethyl methacrylate.

The ionic crosslinking bond can be formed, for example, by reacting a polyvalent metal compound with a carboxyl group of a vinyl polymer having a carboxyl group.

In order to obtain such a vinyl polymer having a carboxyl group, polymerization may be carried out using a monomer selected from acrylic acid or methacrylic acid and derivatives thereof as an essential component. For example, a half-ester compound having a structure obtained by an esterification reaction between an acrylic ester or methacrylic ester having a hydroxyl group, or a derivative thereof, and a dicarboxylic acid compound can be used.

Specific examples of half-ester compounds include succinic acid monoacryloyloxyethyl ester, succinic acid monoacryloyloxypropyl ester, glutaric acid monoacryloyloxyethyl ester, phthalic acid monoacryloyloxyethyl ester, phthalic acid monoacryloyloxypropyl ester, and succinic acid monoacryloyloxyethyl ester. Examples include acid monomethacryloyloxyethyl ester, succinic acid monomethacryloyloxypropyl ester, glutaric acid monomethacryloyloxyethyl ester, phthalic acid monomethacryloyloxyethyl ester, and phthalic acid monomethacryloyloxypropyl ester.

The metal element of the polyvalent metal compound to be reacted with the carboxyl group of the vinyl polymer having a carboxyl group is as follows:
CuSAg, Be, Mg, Ca.

Sr, Ba1Zn, Cd, AI, Ti5GeSSn, V
, CrSMoSMn, Fe, Ni, Co.

Zr, Se, etc. can be mentioned. Among these, alkaline earth metals (Be, Mg, Ca, Sr, Ba) and zinc group elements (Zn, Cd) are preferred, with Mg and Zn being particularly preferred.

Examples of polyvalent metal compounds containing these metals include:
Fluorides, chlorides, chlorates, bromides, iodides, oxides, hydroxides, sulfides, sulfites, sulfates, selenides, tellurides, nitrides, nitrates, phosphides of the above metal elements, Examples include phosphinates, phosphates, carbonates, orthosilicates, acetates, oxalates, and lower alkyl metal compounds such as methyl compounds or ethyl compounds. Among these, acetates of the above metal elements and oxides of the above metal elements are preferred.

The amount of the polyvalent metal compound added cannot be generally specified, but is, for example, 0.1 per mole of the vinyl polymer.
It is about 1 mole.

In order to react a polyvalent metal compound with the carboxyl group of a vinyl polymer having a carboxyl group, for example, a polyvalent metal compound is added to a solution containing a vinyl polymer having a carboxyl group obtained by polymerization by a solution polymerization method. Alternatively, the dispersion solution of the polyvalent metal compound is mixed and heated to about 1
It is preferable to carry out the solvent removal treatment for ~3 hours, and after the temperature in the reaction system reaches approximately 150 to 180°C, this temperature is maintained for at least 1 hour to complete the reaction. In some cases, a polyvalent metal compound may be present in the reaction system together with a solvent before starting the polymerization of the vinyl polymer having carboxyl groups, or the carboxyl groups obtained by the above-mentioned solvent removal treatment may be The existing vinyl polymer and polyvalent metal compound may be reacted by melt-kneading them using a roll mill, kneader, extruder, or the like.

In this way, the ionically crosslinked amorphous vinyl polymer obtained by the reaction of the vinyl polymer having a carboxyl group and the polyvalent metal compound is produced by the reaction between the carboxyl group and the polyvalent metal atom of the vinyl polymer having the carboxyl group. are combined by ionic bonds, and a kind of crosslinked structure is formed by these ionic bonds. This ionic bond is a much looser bond than a covalent bond.

Further, from the viewpoint of further improving low-temperature fixing properties and anti-offset properties, it is preferable that the ionically crosslinked amorphous vinyl polymer has at least two maximum values in its molecular weight distribution. Specifically, it has a molecular weight distribution divided into at least two groups: a low molecular weight component with a small maximum molecular weight value and a high molecular weight component with a large maximum molecular weight value, and has a molecular weight measured by gel permutation chromatography (GPC). In the distribution curve, at least one local maximum value is within the range of 2.000 to 20.000, and at least one local maximum value is within the range of 100.000 to 1.000.000.
Preferably, it has at least two maximum values, such that it is within the range of . Furthermore, since the above-mentioned high molecular weight components can make the ionically crosslinked amorphous vinyl polymer even stronger, it has a greater effect of suppressing the destruction of toner particles during friction with the carrier or collision with the photoreceptor. The generation of fine powder that causes toner filming is suppressed. The proportion of the high molecular weight component is preferably 15% by weight or more, particularly preferably 15 to 50% by weight, of the ionically crosslinked amorphous vinyl polymer.

When the ionically crosslinked amorphous vinyl polymer is composed of a high molecular weight component and a low molecular weight component as described above, it is preferable that a carboxyl group that reacts with a polyvalent metal compound is introduced into at least the low molecular weight component. . That is,
The destruction of toner particles caused by friction with the carrier or collision with the surface of the photoreceptor is mainly caused by low molecular weight and relatively brittle components in the toner particles. By cross-linking with a metal compound through so-called ionic bonds and making it strong, it is possible to effectively prevent the generation of fine powder that causes toner filming caused by the destruction of toner particles.

Further, in the ionically crosslinked amorphous vinyl polymer, the ratio Mw/Mn between the weight average molecular weight Mw and the number average molecular weight Mn is preferably 3.5 or more, particularly preferably 4 to 40. When the ratio Mw/Mn is too small, sufficient offset resistance and durability cannot be obtained.

Here, the values of Mw and Mn were measured by GPC under the conditions shown below.

At a temperature of 40°C, a solvent (tetrahydrofuran) is flowed at a flow rate of 1.2-min per minute, and a sample solution of 3 mg of tetrahydrofuran with a concentration of 0.2 g/2 (W) is injected and measured. Select measurement conditions that fall within a range where the molecular weight of the sample in question or the logarithm of the molecular weight of a calibration curve prepared using several types of monodispersed polystyrene standard samples and the count number are a straight line. Reliability is N measured under the above measurement conditions.
B S 706 boristyrene standard sample (Mw=28.
8xlO', Mn=13.7xH', ratio Mw
/Mn=2. The value of the ratio Mw/Mn of Il) is 2.11±0
．． Confirm by determining IQ.

Furthermore, any GPC column may be used as long as it satisfies the above conditions.

Specifically, for example, TSK-GEL, GMH (manufactured by Toyo Soda Co., Ltd.), etc. can be used. Note that the solvent and measurement temperature are not limited to the above conditions, and may be changed to other conditions as appropriate.

As the ionically crosslinked amorphous vinyl polymer, it is preferable to use one having at least two maximum values in the molecular weight distribution curve as described above. Not limited. For example, a first stage polymerization is performed to obtain either a high molecular weight component with a large maximum molecular weight value or a low molecular weight component with a small maximum molecular weight value, and one component obtained thereby is used to obtain the other component. by dissolving it in a monomer composition for a second stage of polymerization and thereby producing the other component, resulting in a polymer having at least two maximum values in the molecular weight distribution curve. I can do it.

It is presumed that the polymer obtained by the two-stage polymerization is a mixture of a low molecular weight component and a high molecular weight component uniformly at the molecular level. This two-stage polymerization can be carried out by, for example, a solution polymerization method, a suspension polymerization method, an emulsion polymerization method, etc., and a solution polymerization method is particularly preferred.

Furthermore, a polymer having at least two maximum values in the molecular weight distribution curve can also be obtained by mixing a low molecular weight polymer component with a small maximum molecular weight value and a high molecular weight polymer component with a large maximum molecular weight value. I can do it.

Further, from the viewpoint of further improving low-temperature fixability, offset resistance, and durability, the glass transition point Tg of the ionically crosslinked amorphous vinyl polymer is preferably 50 to 100°C, particularly preferably 50 to 85°C. Here, the glass transition point Tg
is a value measured based on differential scanning calorimetry (DSC), specifically using rDSC-20J (manufactured by Seiko Electronics Co., Ltd.) at a heating rate of 10°C/min.
The temperature at the intersection of the extension line of the baseline below the glass transition point and the tangent line showing the maximum slope from the rising part of the peak to the apex of the peak when measured at .

The crystalline polyester that forms a block copolymer or graft copolymer with the above-mentioned ionically crosslinked amorphous vinyl polymer has a crystal structure in at least a part of the polyester, and is a homopolymer or copolymer. It contains at least one component that is crystalline, that is, partially crystallized, and exhibits a sharp and clear melting point, and in the solid state at a temperature below the melting point, it exhibits clouding due to the crystallized portion.

As such crystalline polyester, polyalkylene polyester is particularly preferred from the viewpoint of low-temperature fixability and fluidity. Specifically, polyethylene sebacate, polyethylene adipate, polyethylene adipate, polyethylene succinate, polyethylene-p-(carbophenoxy) undecaate, polyhexamethylene offsalate,
Polyhexamethylene sebacate, polyhexamethylene decanedioate, polyoctamethylene dodecanedioate, polynonamethylene acelate, polydecamethylene adipate, polydecamethylene azelate, polydecamethylene offsalate, polydecamethylene sebacate , polydecamethylene adipate, polydecamethylene dodecanedioate, polydecamethylene octadecanedioate,
Polytetramethylene sebacate, polytrimethylene dodecanedioate, polytrimethylene octadecanedioate, polydecamethylene azelate, polyhexamethylene-decamethylene-sebacate, polyoxydecamethylene-2-methyl-1,3-propane-dodecanedioate Eth, etc. can be mentioned.

The melting point Tm of the crystalline polyester is 50 to 120"c,
Particularly preferred is 50 to +00°C. When the melting point Tm is too low, blocking resistance tends to deteriorate;
When the amount is too high, low temperature fixing properties tend to deteriorate. Note that the melting point Tm of this crystalline polyester was measured in a state where it was not bonded to an ionically crosslinked amorphous vinyl polymer. Note that melting point Tm refers to differential scanning calorimetry (D
SC), 10 mg of sample was heated at a constant heating rate (1
It refers to the melting peak value when heated at 0°C/m1n).

In addition, as a crystalline polyester, its Mw is 5.0
00~50.000, Mn or 2.000~20. oo
o is preferred.

Further, it is preferable that the crystalline polyester and the ionically crosslinked amorphous vinyl polymer are substantially incompatible. In addition,
Substantially incompatible means that the crystalline polyester and the ionically crosslinked amorphous vinyl polymer are not sufficiently dispersed;
Specifically, for example, S, P, value CR, F, FedorsPolym, Eng, S by Fetose's method
ci,, +4. (2) 147 (1974)) is greater than 0.5.

In order to obtain a block copolymer or a graft copolymer formed by chemically bonding a crystalline polyester and an ionically crosslinked amorphous vinyl polymer, for example, a head-to-tail copolymer is formed by campling reaction between terminal functional groups. They can be bonded directly to each other or via a terminal functional group and a bifunctional coupling agent. For example, a urethane bond formed by the reaction of a polymer with terminal or hydroxyl groups and a diisocyanate, a reaction of a polymer with terminal or hydroxyl groups with a dicarboxylic acid, or a reaction of a polymer with terminal or carboxyl groups with a glycol. The bond can be formed by an ester bond formed by ester bond, or another bond formed by reaction of a polymer whose terminal group is a hydroxyl group with phosgene or dichlorodimethylsilane.

Such coupling agents include difunctional isocyanates such as hexamethylene diisocyanate, diphenylmethane diisocyanate, tolylene diisocyanate, tolidine diisocyanate, naphthylene diisocyanate, isophorone diisocyanate, and xylylene diisocyanate.

Difunctional amines such as ethylenediamine, hexamethylenediamine, phenylenediamine: oxalic acid, succinic acid,
Difunctional carboxylic acids such as adipic acid, sebacic acid, terephthalic acid, and isophthalic acid; difunctional alcohols such as ethylene glycol, propylene glycol, butanediol, bentanediol, hexanediol, cyclohexane dimetatool, and p-xylylene glycol: Difunctional acid chloride such as terephthalic acid chloride, isophthalic acid chloride, adipic acid chloride, sebacic acid chloride, other bifunctional coupling agents such as diisothiocyanate, bisketene, bis-sulfodiimide; etc. .

The coupling agent is preferably used in an amount of 1 to 10% by weight, particularly 2 to 7% by weight, based on the total amount of the crystalline polyester and the ionically crosslinked amorphous vinyl polymer. When the proportion of the coupling agent is too large, the softening point of the resulting block copolymer or graft copolymer becomes too high, which tends to deteriorate low-temperature fixing properties, while when the proportion is too small, anti-offset properties tend to deteriorate.

The chloroform-insoluble content of the specific copolymer is preferably 3% by weight or more and IO% by weight or less. Within this range, low-temperature fixing properties can be extremely stably ensured without substantially impairing anti-offset properties.

That is, the chloroform-insoluble matter is a high molecular weight component, and this high molecular weight component is 3 to IO in a specific copolymer.
If it is present in a proportion of % by weight, the offset generation temperature is high and a suitable fixing temperature range is wide, even though the softening point is low. As a result, the conditions for controlling the temperature of the heat roller of the fuser in order to achieve sufficient fixing without causing the offset phenomenon are greatly relaxed, and the offset phenomenon due to non-uniformity of the temperature of the heat roller is prevented. This makes it possible to reliably achieve good fixing without any imperfections.

However, if the specific copolymer is insoluble in chloroform or has less than 3% by weight, it may be difficult to sufficiently improve offset resistance. On the other hand, whether chloroform is insoluble or
If it exceeds 0% by weight, low-temperature fixing properties may be impaired.

In the present invention, the chloroform-insoluble content refers to the content that does not pass through a filter paper when a sample is dissolved in chloroform, and is determined as follows.

Finely grind a specific copolymer (sample), collect 5.00 g of sample powder that has passed through a 40-mesh sieve, and combine it with 5.00 g of the filter aid Lanolide (100) in a volume of 150 m.
1, and 100 g of chloroform is poured into the container, and the sample is placed on a ball mill stand and rotated for 5 hours or more to fully dissolve the sample in the chloroform. On the other hand, a filter paper with a diameter of 7 cm (of Nα2) was placed in a pressure filter, 5.00 g of Radiolite was pre-coated uniformly on it, and a small amount of chloroform was added to make the filter paper adhere to the filter. Thereafter, the contents of the container are poured into a filter. Furthermore, the container is sufficiently washed with 100 me chloroform and poured into a filter to ensure that no deposits remain on the wall of the container. Then, close the top lid of the filter and perform filtration. Filtration is performed under pressure of 4 kg/cm" or less, and after the outflow of chloroform has stopped, 100% chloroform is added to wash the residue on the filter paper, and pressure filtration is performed again.

After the above operations are completed, the filter paper, the residue on it, and the radiolite are all placed on aluminum foil and placed in a vacuum dryer, at a temperature of 80-100°C and a pressure of 100°C.
Dry for 10 hours under mmHg conditions, measure the total weight a (g) of the dry solid product thus obtained, and determine the chloroform insoluble content X (wt%) using the following formula.

X (weight %) = sampling weight (5.0 Og) × 100 The chloroform-insoluble content determined in this way is a high molecular weight polymer component or a crosslinked polymer component, and its molecular weight is approximately 400.000 or more. It is thought that.

The chloroform-insoluble content in a specific copolymer is determined by the polymerization reaction temperature,
It can be controlled to a considerable extent by appropriately selecting reaction conditions such as polymerization time, or by allowing an appropriate crosslinking agent to be present in the reaction system.

In the present invention, the specific block copolymer or graft copolymer described above is used as the binder resin, but other resins may be used in combination as necessary. However, the proportion of the block copolymer or graft copolymer in the toner is preferably 30% by weight or more.

The toner may contain various additives as necessary. Examples of such additives include colorants, charge control agents, fixability improvers, and surface treatment agents.

Colorants include carbon black, nigrosine dye,
Aniline blue, Calfoil blue chrome yellow,
Examples include ultramarine blue, DuPont oil red, quinoline yellow, methylene blue chloride, phthalocyanine blue, malachite green offsalate, lamp black, rose bengal, and mixtures thereof.

Examples of the charge control agent include metal complex dyes, nigrosine dyes, ammonium compounds, and the like.

Fixability improvers include polyolefins, fatty acid metal salts, fatty acid esters and fatty acid ester waxes, partially saponified fatty acid esters, higher fatty acids, higher alcohols, liquid or solid paraffin waxes, polyamide waxes, polyhydric alcohol esters, Examples include silicone face and aliphatic fluorocarbon. In particular, the ring and ball method (JIS K 2531-1960) +:
Waxes having a softening point of 60 to 15°C are preferred.

Examples of the surface treatment agent include organic fine particles. Specifically, styrene-acrylic resin, polymethyl methacrylate resin, and acrylic resin described in JP-A-1-105261 have a glass transition point Tg of 50°C.
The above organic fine particles are preferred.

These organic fine particles are preferably used while being fixed on the toner surface by mechanical impact force.

Further, external additives such as inorganic fine particles may be added and mixed in the toner. Specific examples of inorganic fine particles include silica, alumina, titanium oxide, barium titanate, magnesium titanate, calcium titanate, strontium titanate, zinc oxide, silica sand, clay, mica, wollastonite, diatomaceous earth, and chromium oxide. , cerium oxide, red iron oxide, antimony trioxide, magnesium oxide, zirconium oxide, barium sulfate, barium carbonate, calcium carbonate,
Examples include silicon carbide and silicon nitride. Particularly preferred is silica fine powder.

Further, when obtaining a magnetic toner, fine particles of magnetic material are contained in the toner particles. Such magnetic materials include iron,
Examples include ferromagnetic substances such as ferrite and magnetite.

In the case of a two-component developer, the toner and carrier are mixed to form the developer. Such a carrier is not particularly limited, and conventionally known carriers can be used. Specifically, there are uncoated carriers made of only magnetic particles, resin-coated carriers in which the surfaces of magnetic particles are coated with resin, and magnetic material-dispersed carriers in which magnetic particles are dispersed in resin particles. A carrier etc. can be used. The average particle size of the carrier is 20 to 200
The thickness is preferably .mu.m, particularly preferably 30 to 150 .mu.m.

Here, the average particle diameter (weight) of the carrier was measured using "Microtrack" (manufactured by Nikkiso Co., Ltd.).

Examples of magnetic particles used in the carrier include iron,
Ferromagnetic metals such as nickel and cobalt, alloys containing these metals, compounds of ferromagnetic metals such as ferrite and magnetite, alloys that do not contain ferromagnetic elements or become ferromagnetic by appropriate heat treatment, e.g. Manganese
Mention may be made of alloys of the type called Heusler alloys such as copper-aluminum, manganese-copper-tin, etc., or particles such as chromium dioxide.

Examples of the resin used for the resin-coated carrier include vinylidene fluoride-tetrafluoroethylene copolymer, tetrafluoroethylene, methyl methacrylate-1,1-dihydroxyperfluoroethyl methacrylate copolymer,
Fluororesins such as styrene-methacrylic acid-1,1,3-trihydroxyperfluoro n-propyl copolymer:
For example, vinyl resins such as polystyrene, styrene-methyl methacrylate copolymer, styrene-n-butyl acrylate copolymer, styrene-2-ethylhexyl copolymer, polymethyl methacrylate, styrene-butadiene copolymer; for example, silane coupling silicone compounds such as silicone oils, silicone oils, silicone varnishes, silicone rubbers, silicone resins, and cured products thereof. The above-mentioned substances may be used alone or in an appropriate combination of multiple types.

In the present invention, a photoreceptor (a-S
i Photoreceptor) is used.

a-3i Substances constituting the bad sensitivity include amorphous silicon, amorphous silicon germanium, amorphous silicon tin, or those containing carbon, nitrogen, oxygen, etc., and elements of Group IIIa of the periodic table or Va. It is possible to use doped elements of the group. Among these, amorphous silicon is particularly preferred.

In a specific example of an a-Si photoreceptor, as shown in FIG. 1, a blocking material made of aluminum oxide or the like is placed on the outer peripheral surface of a rotating drum-shaped conductive support 2 made of metal such as stainless steel. A layer 3 is provided, this blocking layer 3
An a-3i photoreceptor 4 is provided on top to form an a-Si photoreceptor 1. The blocking layer 3 is a-
3i It is provided as necessary to prevent the injection of charge into the ill-sensing light 4.

The a-Si photosensitive layer 4 can be formed using a thin film forming technique such as a glow discharge method, a sputtering method, an ion blating method, or a vapor deposition method. The thickness of this a-81 photosensitive layer 4 is usually preferably about 5 to 50 μm.

The blocking layer 3 is formed by oxidizing the surface of the conductive support 2 made of metal using an oxidizing means such as anodizing, oxidizing, or plasma oxidizing, or by oxidizing silicon oxide, silicon oxide, etc. in a vacuum chamber. It can be formed by depositing an insulating substance such as aluminum oxide, chromium oxide, titanium oxide, zirconium oxide, silicon nitride, magnesium fluoride, zinc sulfide, etc. on the surface of the conductive support 2. can.

FIG. 2 shows an example of an image forming apparatus that can be suitably used in the present invention. 1 is an a-Si photoreceptor having an a-3i bad sensitivity, and this a-Si photoreceptor l has a rotating drum shape. Around the a-3i ill-sensing light 1, from the upstream side to the downstream side in the direction of rotation, there are, in order, a corona charger 5, an exposure optical system 6, a contact type magnetic plan developer 7, an electrostatic transfer device 8, and a separator. 9. A blade type cleaning device IO is arranged. 11 is a heat roller fixing device.

In this image forming apparatus, the corona charger 5
The surface of the -3i bad photo 1 is charged to a --like potential, and then imagewise exposed by the exposure optical system 6 to form an electrostatic image corresponding to the original on the surface of the a-3i bad photo 1. Then, the electrostatic image is developed by applying a magnetic brush developing method with a developer containing a toner containing the specific copolymer as a binder resin, which is housed in a contact type magnetic brush developing device 7. A toner image corresponding to the original is formed. This toner image is electrostatically transferred onto a transfer material 12 by an electrostatic transfer device 8, and heated and fixed by a heat roller fixing device 11 to form a fixed image. On the other hand, a-3 that has passed through the electrostatic transfer device 8
The surface of the negative exposure light 1 is rubbed by a blade-type cleaning device 1O to scrape off the residual toner, making it the original clean surface, and then subjected to the charging process by the corona charger 5 again to produce the next image. used for the formation of

In the fixing step, a heat roller fixing method can be preferably employed. A heat roller fixing device used in a heat roller fixing method is usually composed of a heat roller, a backup roller disposed in opposition to the heat roller, and a heat source. Further, a cleaning roller is arranged opposite to the heat roller as necessary. The temperature of the heat roller is maintained within a certain range by a heat source, and the toner or the transferred recording material is passed between the heat roller and the backup roller, so that the toner is brought into direct contact with the heat roller. Heat fixes the toner onto the recording material. The surface material of the heat roller is preferably a fluorine-based material or a silicone-based material, and the synergistic effect with the above-mentioned specific toner can significantly improve the durability of the heat roller fixing device.

〔Example〕

Examples of the present invention will be described below along with comparative examples, but the embodiments of the present invention are not limited to these Examples. In addition, in the following, ``part r'' represents ``part by weight J.''

<Crystalline polyester 1> Sebacic acid 1500 g Hexamethylene glycol 964 g or more of the monomer was placed in a 5p round bottom flask equipped with a thermometer, a stainless steel stirrer, a glass nitrogen gas inlet tube and a down-flow condenser. Then, the flask was placed in a mantle heater, and nitrogen gas was introduced from a glass nitrogen gas introduction tube to raise the temperature while maintaining an inert atmosphere inside the reactor.

Thereafter, 13.2 g of p-toluenesulfonic acid was added and reacted at a temperature of 150°C. The reaction is stopped when the amount of water distilled by the esterification reaction reaches 250-
The reactant was taken out. This was cooled to room temperature to obtain a crystalline polyester 1 consisting of polyhexamethylene sebacate having a hydroxyl group at the end of the molecule. The melting point Tm of this crystalline polyester l is 64°C, the weight average molecular weight Mw is 1
It was 4,000.

Crystalline polyester 2> By the same manufacturing method as crystalline polyester 1, Tm=
Crystalline polyester 2 made of polyethylene sebacate at 72°C and Mw=12.800 was obtained.

Amorphous vinyl polymer 1> Put 100 parts of toluene in a separable flask with a capacity of 11, and add 755 parts of styrene as monomers for high molecular weight components, 25 parts of n-butyl acrylate, and 0.2 parts of benzoyl peroxide. was added, suspended and dispersed, and the gas phase in the flask was replaced with nitrogen gas, and then the temperature was raised to 80°C and maintained at that temperature for 15 hours to carry out the first stage polymerization. The homopolymer of this monomer for high molecular weight components has an Mw of 461.000 and a Tg of 61"C.
There was.

Thereafter, the inside of the flask was cooled to a temperature of 40°C, and styrene was added as a monomer for low molecular weight components.
85 parts n-butyl methacrylate
10 parts acrylic acid
5 parts benzoyl peroxide 4
After stirring was continued for 2 hours at a temperature of 40°C, the temperature was raised again to 80°C and maintained at that temperature for 8 hours to carry out second stage polymerization. The homopolymer of this monomer for low molecular weight components has an Mw of 8.200 and a Tg of 64.
It was °C.

Next, add 0 zinc oxide, which is a polyvalent metal compound, to the flask.
．． 5 g was added, and the reaction was carried out for 2 hours while maintaining the temperature at reflux and stirring.

After that, the reaction system is cooled to separate the solid matter, and after repeated dehydration and washing, it is dried to form an amorphous vinyl that is produced by reacting zinc oxide with the carboxyl groups of the vinyl polymer to form ionic crosslinks. Polymer 1 was obtained. This polymer 1 has a carboxyl group as a functional group for bonding with the crystalline polyester.

This polymer 1 has two peaks in the molecular weight distribution by GPC, 363.000 on the high molecular weight side and 7,590 on the low molecular weight side), Mw is 165.000, and the ratio Mw/M
The value of n is 25.9, Tg is 66°C1, the softening point Tsp is 1
The temperature was 30°C.

<Amorphous vinyl polymer 2> 100 parts of toluene was placed in a separable flask with a capacity of 11, and 85 parts of styrene, 10 parts of n-butyl acrylate, and 5 parts of acryloyloxyethyl monosuccinate were added as monomers for high molecular weight components. 1 part of benzoyl peroxide was added and dispersed, and the gas phase in the flask was replaced with nitrogen gas, and then the temperature was raised to 80°C and maintained at that temperature for 5 hours to carry out polymerization.

After that, 4 parts of benzoyl peroxide was further added and the temperature was 8.
Polymerization was continued at 0°C for 10 hours.

Next, add 0 zinc oxide, which is a polyvalent metal compound, to the flask.
．． 3 g was added, and the reaction was carried out for 2 hours while maintaining the temperature at reflux and stirring.

Thereafter, toluene was distilled off using an aspirator and a vacuum pump to obtain an amorphous vinyl polymer 2 in which carboxyl groups of the vinyl polymer were reacted with zinc oxide to form ionic crosslinks. This polymer 2 has a carboxyl group as a functional group for bonding with the crystalline polyester.

This polymer 2 has one peak in the molecular weight distribution by GPC, the Mw is 125.000, and the ratio Mw/Mn
The value is l083, Tg is 62°C1, softening point Tsp is 12
The temperature was 7°C.

Copolymer A> Crystalline polyester 1 15 parts Amorphous vinyl polymer 1 85 parts p-h Luenesulfonic acid 0.05 part xylene
100 parts of the above ingredients in a volume of 31
The xylene was placed in a separable flask and refluxed for 1 hour at a temperature of 150°C.
The mixture was then distilled off using a vacuum pump to obtain a graft copolymer of crystalline polyester and ionically crosslinked amorphous vinyl polymer. This is made into a copolymer.

The chloroform insoluble content in this copolymer is 7.5% by weight9
It was 3.

Copolymer B> Crystalline polyester 2 20 parts Amorphous vinyl polymer 1 80 parts In the production of the copolymer, the same procedure was carried out except that the crystalline polyester and the amorphous vinyl polymer were changed as described above. Copolymer B having a chloroform-insoluble content of 4.0% by weight was obtained.

Copolymer C> Crystalline polyester 1 15 parts Amorphous vinyl polymer 2 85 parts In the production of copolymer A, the crystalline polyester and amorphous vinyl polymer were changed as above, and refluxed in xylene. A copolymer C having a chloroform-insoluble content of 9.0% by weight was obtained in the same manner except that the time was changed to 3 hours.

Toner A-C> Copolymer A 100 parts Carbon black IO part Fixability improver 3 parts or more of the materials are mixed, melted and kneaded with heated rolls, cooled, coarsely pulverized, and further processed with a supersonic jet mill. The powder was pulverized and then classified using an air classifier to obtain a powder.

To 100 parts of this powder, 0.8 parts of hydrophobic phosphoric acid fine powder was added and mixed using a V-type mixer to obtain a toner having an average particle size of 11.08 m.

Further, toners B and C were obtained in the same manner as above except that copolymer A was changed to copolymers B and C, respectively.

<Developer A-C> Toner A and electrophotographic copying machine r U-Bix 500
A developer A having a toner concentration of 6% by weight was prepared by mixing with a carrier for 0J (manufactured by Konica ■).

Further, developers B and C were obtained in the same manner as above except that toner A was changed to toners B and C, respectively.

<Photoreceptor> (1) a-Si photoreceptor 1 A blocking layer made of aluminum oxide is provided on a rotating drum-shaped conductive support made of stainless steel, and an a-3i photoreceptor is provided on this blocking layer. a-3
i Obtained 1 nausea.

(2) OPC photoreceptor 1 A negatively charged laminated ff1OPc photosensitive layer constructed using an anthanthrone pigment as a carrier generating substance and a carbazole derivative as a carrier transporting substance is attached to a rotating drum-shaped conductive support made of aluminum. An OPC photoreceptor was obtained by laminating on top of the photoreceptor.

[Examples 1 to 3] Electrophotographic copying machine "U-Bi" equipped with a-Si photoreceptor sound
Using a modified machine x 5000J (manufactured by ml Nika) and each of the developers A to C, copy images are continuously formed 50,000 times under environmental conditions of a temperature of 20° C. and a relative humidity of 50%. A live-action test was conducted and the following items were evaluated.

In the above electrophotographic copying machine, the developing device is a contact type magnetic brush developing device for two-component developer.

The surface layer of the fixing device is made of PFA (tetrafluoroethylene/
A heat roller with a diameter of 50 mm made of (perfluoroalkyl vinyl ether copolymer) and a silicone rubber rKE-1300RTVJ whose surface layer is coated with PFA.
(manufactured by Shin-Etsu Chemical Co., Ltd.).

This is a heat roller fixing device having a pull-up roller.

The cleaning device is a blade type cleaning device equipped with a cleaning blade made of urethane rubber.

<Low temperature fixability> An unfixed toner image is formed on plain paper using an electrophotographic copying machine "U-Bix 50001", and this toner image is
Linear speed 209mm/see, linear pressure 1.6kg/cm,
The fixing operation with a nip width of 4.5 mm was repeated at each temperature by changing the set temperature of the heat roller in steps of 5°C, and the resulting fixed toner image was subjected to Kimwibe rubbing to ensure sufficient The lowest set temperature (minimum fixing temperature) for a fixed toner image exhibiting abrasion resistance was measured.

Note that the heat roller fixing device is not equipped with a mechanism for applying a release agent such as silicone oil.

<Offset resistance> Immediately after forming a fixed toner image in the same manner as in the low-temperature fixing described above, send a blank sheet of plain paper to the heat roller fixing device under the same conditions and visually check whether or not toner stains occur on it. Perform the observation operation at each set temperature of the heat roller,
The lowest set temperature (offset generation temperature) when toner staining occurred was measured.

Photoreceptor scratches> Set the temperature of the upper roller (heat roller) of the heat roller fuser to 1.
Continuous copying was carried out at 60° C., and the photoreceptor was pulled out every 1000 copies to visually confirm the presence or absence of scratches on the photoreceptor.

Image Blur> The final fixed image was visually observed and evaluated in the same manner as for photoreceptor scratches described above.

[Comparative Example 1] Production of binder resin> 299 g of terephthalic acid and polyoxypropylene (2,
2) 211 g of -2,2-bis(4-hydroxyphenyl)propane and 82 g of pentaerythritol were placed in a round-bottomed flask equipped with a thermometer, a stainless steel stirrer, a glass nitrogen gas inlet tube, and a down-flow condenser. The flask was placed in a mantle heater, and nitrogen gas was introduced from the nitrogen gas inlet tube to raise the temperature while maintaining an inert atmosphere inside the flask. Next, 0.05 g of dibutyltin oxide was added and reacted at a temperature of 200°C while monitoring the reaction at the softening point, resulting in a chloroform insoluble content of 17% by weight, JIS K 2531-19.
A comparative polyester resin having a ring and ball softening point of 131''C at 60° C. was obtained. This is referred to as polyester resin a.

<Manufacture of toner> 100 parts of the above polyester resin a, 10 parts of carbon black, and 3 parts or more of low molecular weight polypropylene were melt-kneaded, cooled, crushed, and classified to obtain a colored powder with an average particle size of 10 μm.

Add 1 powder of organic fine particles (polymethyl methacrylate fine particles, average diameter of -order particles = 500 nm) to this colored powder.
．． 0% by weight, fluidizing agent rR-972J (hydrophobic silica fine particles, average diameter of particles = 16 nm.

Toner D for comparison was obtained by mixing and stirring 0.8% by weight of Toner (manufactured by Nippon Aerosil Co., Ltd.).

Preparation of developer> The average particle size of ferrite particles whose surfaces are coated with methyl methacrylate/styrene copolymer resin is 100.
A comparative developer a having a toner concentration of 4% by weight was obtained by mixing the carrier coated with .mu.m and the above-mentioned toner D.

Actual photo test> Using the developer a for comparison, a photo test was conducted in the same manner as in the examples, and the same items as in the examples were evaluated.

[Comparative Example 2] ○Electrophotographic copying machine “U-Bix” equipped with PC photoreceptor 1
Using a modified 1550MRJ (manufactured by MLN Riki) and the comparative developer a obtained in Comparative Example 1, the temperature was 2°C.
1. A photocopy test was conducted in which a copy image was continuously formed 30,000 times under an environmental condition of 50% relative humidity, and the same items as in the examples were evaluated.

In the above electrophotographic copying machine, the developing device is a contact magnetic brush developing device for two-component developer.

The surface layer of the fixing device is made of PFA (tetrafluoroethylene/
A heated roller with a diameter of 30 mm made of (perfluoroalkyl vinyl ether copolymer) and a silicone rubber rKE-1300RTVJ whose surface layer is coated with PFA.
(manufactured by Shin-Etsu Chemical Co., Ltd.). The cleaning device is a blade type cleaning device equipped with a cleaning blade made of urethane rubber.

The characteristics of the above toners A to D are summarized in Table 1 below. Further, Table 2 below shows the results of the live-action test.

From Table 2, it is clear that the Examples of the present invention are excellent in all aspects of low-temperature fixability, offset resistance, prevention of photoreceptor scratches, and prevention of image blur.

On the other hand, in Comparative Example 1, since the binder resin was not a specific copolymer but a polyester resin, low-temperature fixability was poor, image blurring was likely to occur, and photoreceptor scratches were likely to occur.

In Comparative Example 2, the binder resin was not a specific copolymer but a polyester resin, and the photoreceptor or OPC photoreceptor had poor low-temperature fixing properties, image blurring, and photoreceptor scratches. is also likely to occur.

〔Effect of the invention〕

As explained above, the present invention not only has excellent low-temperature fixing properties and anti-offset properties, but also effectively prevents photoreceptor scratches and can stably produce good images without image blur over many times. can be formed.

In addition, the chloroform-insoluble portion of the binder resin was reduced to 3 to 10
If the weight percent range is specified, even better low-temperature fixing properties and anti-offset properties will be exhibited.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional view of an example of a specific configuration of an a-3i nausea photo, and FIG. 2 is an explanatory diagram of an example of an image forming apparatus. 1... a -3i bad light sensitivity 2... conductive support 3... blocking layer 4... a -Si photosensitive layer 5... corona charger 6... exposure optical system 7...
・Contact type magnetic brush developer 8... Electrostatic transfer device 9... Separator 10...
Blade type cleaning device

Claims (2)

[Claims] (1) An electrostatic image formed on a photoreceptor having an amorphous silicon photosensitive layer is formed by chemically bonding 3 to 50 parts by weight of crystalline polyester and 97 to 50 parts by weight of ionically crosslinked amorphous vinyl polymer. An image forming method comprising developing with a toner containing a block copolymer or a graft copolymer as a binder resin. (2) An image forming method, wherein the chloroform-insoluble content of the binder resin of the toner according to claim 1 is 3% by weight or more and 10% by weight or less.