JPH08171234A - Picture forming method - Google Patents

Abstract

PURPOSE: To provide a picture forming method without generating of malodor and with an ozone filter capable of being removed from a picture forming device. CONSTITUTION: The photoreceptor is charged by a contact charging means impressed with a bias, an electrostatic charge image is formed on the charged photoreceptor, the electrostatic charge image of the photoreceptor is developed with the toner contg. at least a binder resin and colorant to form a toner image on the photoreceptor, and the toner image on a transfer material is fixed by a heat fixing means, and a picture is formed. The benzaldehyde content of the toner is controlled to <=0.005wt.%, and a styrenic resin is used as the binder resin.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image forming method for developing an electrostatic charge image formed by electrophotography, electrostatic recording or the like with toner.

[0002]

2. Description of the Related Art Conventionally, as an electrophotographic method, U.S. Pat. No. 2,297,691 and JP-B-42-23910 are known.
Although many methods are known, such as Japanese Patent Publication No. 43-24748 and Japanese Patent Publication No. 43-24748, generally, a photoconductive substance is used,
An electric latent image is formed on the photoconductor by various means, then the latent image is developed with a developer, and the developer image is transferred to a transfer material such as paper, if necessary, followed by heating and pressure. , Fixing by heating under pressure or solvent vapor to obtain a copy. Further, when there is a step of transferring the developer image, a step for removing the residual developer is usually provided.

A developing method for visualizing an electric latent image by using a developer is, for example, a magnetic brush method described in US Pat. No. 2,874,063, and a magnetic brush method of 2,618,55.
No. 2, No. 2,221,776, powder cloud method, US Pat. No. 3,909,258, conductive powder method. A method using a magnetic toner is known.

As a toner applied to these developing methods, a fine powder in which a dye or a pigment is dispersed in a natural or synthetic resin has been conventionally used. For example, 1 to 30 is obtained by dispersing a colorant in a binder resin such as polystyrene.
Particles finely pulverized to about μm are used as toner. A magnetic toner containing magnetic particles such as magnetite is used. On the other hand, in the case of a system using a so-called two-component developer, carrier particles such as glass beads and iron powder and toner are usually mixed and used.

Nowadays, such a recording method has been widely used not only for general copying machines but also for computer output and microfilm printing. Therefore, the required performance has become higher, and various performances such as smaller size, lighter weight, lower energy, more maintenance-free, and more personal have been demanded at the same time. In order to satisfy these requirements, the demands on the toner have become more severe in various aspects.

For example, as described above, the range of application is widened,
When used in general offices and homes, it is necessary to pay attention not only to the safety of the toner as a substance but also to the odor generated during fixing. Further, copiers, printers, etc. are often equipped with a filter for deodorization, that is, for adsorbing odors, ozone, etc., but this is also disadvantageous in terms of production cost, and the deodorization performance can be maintained. To do so, there is also the trouble of regular replacement.

This odor problem is naturally an important problem from the standpoint of the users and manufacturers as described above, but in general, a synthetic resin is contained as a main component, and softening / melting due to heating is generally caused. Considering from the method of fixing a toner image that can be fixed to a transfer material such as paper by utilizing it, it is technically not easy. Further, in order to solve this problem, it is meaningless to lower the developing characteristics such as image quality and toner durability.

Various methods have been considered in order to satisfy these performances at the same time. However, in the method of adding an additive, the system becomes complicated, and an unexpected problem often occurs.

Therefore, it is desirable to improve the binder resin itself. For that purpose, it is considered to be good to reduce the residual amount of the odor-causing solvent and the polymerizable monomer in the binder resin, and various methods including the influence on other developing characteristics have been considered so far. Is proposed.

For example, in JP-A-55-155632, as a binder resin for a toner, a solvent used for obtaining a polymer or a polymer having a polymerizable monomer content of less than 0.1% by weight is used. Therefore, it has been proposed to improve the storage stability, fluidity, etc. of offset.

Japanese Patent Laid-Open No. 53-17737 describes that the residue of the polymerizable monomer affects the triboelectric charging property, blocking resistance and fixing property of the toner. As a binder resin for the toner, a polymer is used. It has been proposed to reduce the residual solvent or polymerizable monomer used to obtain the.

In Japanese Patent Laid-Open No. 64-70765, there is a problem that the amount of residual monomer is reduced, especially for the problem that the on-site environment is deteriorated due to the odor generated during melt-kneading, or the odor is generated during copying, which causes discomfort. 200 ppm
The following toner resins have been proposed. It is described that if the amount of residual monomer exceeds 200 ppm, blocking resistance and PVC plasticizer resistance decrease, and the problem of odor also remains.

However, especially when the problem of odor is targeted, it is sufficient to simply reduce the amount of the remaining polymerizable monomer in view of the future expansion of the scope of application such as electrophotography and electrostatic recording. I can't say.

In general, as a method for polymerizing the binder resin for toner, a solution polymerization method, a bulk polymerization method, a suspension polymerization method and the like are known. Especially for the suspension polymerization method, as proposed by the present applicant in Japanese Patent Application No. 62-57358, it is not necessary to remove the solvent, and a strong stirring device is not required, so that the production is easy, and The method is suitable as a method for polymerizing the binder resin for toner, such that a THF insoluble matter, which has a great influence on the fixing and offset resistance performance of the toner, can be contained in an arbitrary amount.

However, in the suspension polymerization method, since the resin is obtained in the form of beads, there is no step of removing the solvent or the polymerizable monomer in the molten state of the resin, such as solution polymerization, and simply removing the water content. Only the intended drying step is performed. As a result, the residual amount of the solvent, the polymerizable monomer, etc. tends to increase, and it is necessary to pay particular attention to the above-mentioned odor problem.

[0016]

SUMMARY OF THE INVENTION It is an object of the present invention to provide an image forming method using the toner for developing an electrostatic image which is excellent in odor and which improves the above drawbacks.

A particular object of the present invention is to provide an image forming method which produces less odor.

Another object of the present invention is to provide an image forming method which simultaneously satisfies not only odor but also excellent performance in other characteristics.

[0019]

SUMMARY OF THE INVENTION The present invention comprises a charging step of charging a photoreceptor with a contact charging means to which a bias is applied, and an electrostatic charge image forming step of forming an electrostatic charge image on the charged photoreceptor. A developing step of developing the electrostatic charge image of the photoconductor with a toner containing at least a binder resin and a colorant to form a toner image on the photoconductor, and fixing the toner image on the transfer material by a heat fixing means. The present invention relates to an image forming method, wherein the toner has a benzaldehyde content of 0.005% by weight or less, and the binder resin is a styrene resin.

The inventors of the present invention have made earnest studies on the factors that influence the odor of the toner. As a result, the amount of the solvent and the polymerizable monomer remaining in the toner is effective, as is the case with the findings obtained so far. However, more than that, the residual amount of those oxidization products, especially the aldehyde produced by aerial oxidation of the polymerizable monomer, has a great influence, and reducing the residual amount of the aldehyde in the toner reduces the residual amount of the aldehyde in the toner. I'm sure it's the best way to prevent odors.

Especially, the odor is the most problematic for the benzaldehyde produced by the air oxidation of the styrene monomer, which is caused by the styrene-based resin such as the styrene-based polymer or copolymer most commonly used as the binder resin for toner. Since it is a component, it is necessary to be careful enough to reduce the residual amount.

According to the studies by the present inventors, the content of benzaldehyde in the toner needs to be 0.005% by weight or less, and particularly preferably 0.004% by weight.
The following is good. When the content of benzaldehyde exceeds 0.005% by weight, the odor of the toner is often noticeable.

In view of the above problems, the present inventors have conducted extensive studies to reduce the amount of benzaldehyde, and have found that the object can be achieved by adopting the method described below.

That is, the benzaldehyde contained in the toner is derived from the styrene resin used as the binder resin which is the main constituent of the toner, and the styrene resin is particularly suitable as the toner. It is remarkably contained when it is produced by suspension polymerization. Therefore, it is essential to reduce the amount of benzaldehyde contained in the styrene resin. In particular, in the styrene-based resin produced by suspension polymerization, in order to reduce the amount of benzaldehyde contained, by minimizing dissolved oxygen in water used during suspension polymerization, air oxidation of styrene monomer is suppressed, As a result, the production of benzaldehyde is suppressed.

That is, conventionally, in the suspension polymerization method, it has been known that the atmosphere of the polymerization system is replaced with nitrogen gas for the purpose of reducing wasteful consumption of the polymerization initiator. Is to prevent a decrease in the polymerization yield, and is insufficient for the purpose of reducing benzaldehyde. It has been found that in order to achieve the reduction of benzaldehyde, it is necessary to reduce dissolved oxygen in water used in suspension polymerization. The mechanism of action is considered as follows. That is, in suspension polymerization, a polymerization reaction occurs in a droplet of a polymerizable monomer containing a styrene monomer suspended in water, and in the place of this polymerization reaction, the droplet of the polymerizable monomer directly contacts with water. It is considered to be strongly affected by dissolved oxygen in the water phase.

Various known techniques can be used as a specific method for reducing the dissolved oxygen.
Preferably, a method of efficiently dissolving oxygen by attaching a nitrogen introducing pipe into water and flowing nitrogen gas into the water is preferable.

Further, a method of heating the suspension of the polymer thus obtained at a temperature of about 70 ° C. or higher and distilling off residual monomers at the same time as distilling off water may be carried out together. .

As described above, it is most effective to reduce the benzaldehyde contained in the binder resin. However, in combination with this, at the time of producing a toner, for example, the binder resin and the colorant, etc. When kneading and is melt-kneaded, it is also effective to take measures such as strong heating and suction removal of volatile matter.

Quantification of benzaldehyde in the toner is carried out by the following method using a gas chromatograph.

2.55 mg of DMF was used as an internal standard, and 1
Make a solvent containing an internal standard by adding 00 ml of acetone. Next, 200 mg of the binder resin is made into a 10 ml solution with the above solvent. After ultrasonically shaking for 30 minutes, leave it for 1 hour. Then, it is filtered with a 0.5 μm filter.
The amount of sample to be implanted is 4 μl.

The conditions of the gas chromatograph are: Capillary column (30 m × 0.249 mm, DBW
AX, film thickness 0.25 μm) ・ Detector FID, nitrogen pressure 0.45 kg / cm ²・ Injection concentration 200 ° C, detector temperature 2
The column temperature is raised from 50 ° C. to 5 ° C./1 minute for 30 minutes. -Preparation of calibration curve The same amount of DMF as the sample solution, and a standard sample obtained by adding the aldehyde of interest to the acetone solution were also measured by gas chromatography, and aldehyde and internal standard DMF were measured.
The weight ratio / area ratio of is calculated.

In the toner used in the present invention,
In order to highly satisfy the offset resistance, the fixing property, the filming property to the photoconductor, the fusion property, the image property, etc., the binder resin GP may be a tetrahydrofuran (THF) soluble component.
In the molecular weight distribution by C, Mw / Mn ≧ 5,
A molecular weight of 10,000 or less is 10 to 50 based on the resin.
Styrenic resins that are weight percent are preferred.

Further, the binder resin contains 10 to 10 parts of THF insoluble matter.
70% by weight (preferably 10 to 60% by weight) is contained, and at least one peak is present in the molecular weight range of 2,000 to 10,000 in the molecular weight distribution by GPC of the THF soluble component. And molecular weight 15,000
It is preferable to have at least one peak or shoulder in the region of 0 to 100,000.

The THF-insoluble matter in the present invention means a gel component in the resin composition constituting the toner, which has been crosslinked to become insoluble in THF, and this weight ratio is the resin composition containing a highly crosslinkable component. It can be used as a parameter indicating the degree of cross-linking. The THF-insoluble matter is defined as a value measured as follows.

That is, when the toner is a non-magnetic toner, the content of the pigment is measured, and when the toner is a magnetic toner, the content of the pigment and the magnetic material is measured in advance by a known method. Next, a certain amount of 0.5 to 1.0 g of toner is weighed (W ₁ g), put into a cylindrical filter paper (No. 86R manufactured by Toyo Roshi Kaisha, Ltd.), applied to a Soxhlet extractor, and THF10 as a solvent is used.
After extracting with 0 to 200 ml for 6 hours and evaporating the soluble component extracted with THF, vacuum drying is performed at 100 ° C. for several hours, and the amount of the THF soluble resin component is weighed (W ₂ g). Of the pigments and magnetic substances contained in the toner fixed amount, the weight of the component soluble in THF is W ₃
g, and the weight of the component insoluble in THF is W ₄ g, the THF insoluble content in the resin composition is calculated according to the following formula.

[0036]

[Equation 1]

The evaporated dry matter of the THF-soluble component obtained by the above operation is dissolved in THF, passed through a sample processing filter, and then used as a sample for GPC (gel permeation chromatography).

In the present invention, the molecular weight of the peak or / and shoulder of the chromatograph by GPC is measured under the following conditions.

That is, the column was stabilized in a heat chamber at 40 ° C., and THF as a solvent was flown through the column at this temperature at a flow rate of 1 ml / min to adjust the sample concentration to 0.05 to 0.1% by weight. 50-200 μl of a THF sample solution of the resin is injected and measured. In measuring the molecular weight of a sample, the molecular weight distribution of the sample is calculated from the relationship between the logarithmic value and the count number of a calibration curve prepared from several kinds of monodisperse polystyrene standard samples. As a standard polystyrene sample for preparing a calibration curve, for example, Pres
Sure Chemical Co. Manufactured by Toyo Soda Kogyo Co., Ltd. having a molecular weight of 6 × 10 ² , 2.1 × 10 ³ , 4
X10 ³ , 1.75 x 10 ⁴ , 5.1 x 10 ⁴ , 1.1
× 10 ⁵ , 3.9 × 10 ⁵ , 8.6 × 10 ⁵ , 2 × 10
^It is appropriate to use ⁶ , 4.48 × 10 ⁶ standard polystyrene samples with at least about 10 points.
An RI (refractive index) detector is used as the detector.

As a column, 10 ³ to 4 × 10
^In order to accurately measure the molecular weight region of ⁶ , it is preferable to combine a plurality of commercially available polystyrene gel columns.
.mu.-styragel 500,10 manufactured by Aters Inc.
Combination of ³ , 10 ⁴ and 10 ⁵ and Sh from Showa Denko KK
odex KF-80M and KF-802,803,8
Combination of 04,805 or TSKg made by Toyo Soda
el G1000H, G2000H, G2500H, G
3000H, G4000H, G5000H, G6000
A combination of H, G7000H and GMH is preferred.

The weight% with respect to the binder resin having a molecular weight of 10,000 or less is obtained by cutting out the molecular weight of 10,000 or less in the chromatogram by GPC and calculating the weight ratio with the cutout having a molecular weight of 10,000 or more. % Is used to calculate the weight% of the total binder resin.

The binder resin in the toner used in the present invention is a styrene resin, which is obtained by polymerizing styrene and one or more kinds of monomers selected from styrenes, acrylic acids, methacrylic acids and their derivatives. It is preferable from the viewpoint of development characteristics and charging characteristics. Examples of monomers that can be used include styrenes such as styrene, α-methylstyrene, vinyltoluene, and chlorostyrene. Acrylic acids, methacrylic acids and their derivatives include acrylic acid, methyl acrylate, ethyl acrylate, propyl acrylate, butyl acrylate, octyl acrylate, 2-ethylhexyl acrylate, n-tetradecyl acrylate, n-acrylic acid. Hexadecyl,
Acrylic acid esters such as lauryl acrylate, cyclohexyl acrylate, diethylaminoethyl acrylate, dimethylaminoethyl acrylate, etc. may be mentioned. Similarly, methacrylic acid, methyl methacrylate, ethyl methacrylate, propyl methacrylate, butyl methacrylate, methacrylic acid may be mentioned. Amyl acid, hexyl methacrylate, 2-ethylhexyl methacrylate, octyl methacrylate, decyl methacrylate, dodecyl methacrylate, lauryl methacrylate, cyclohexyl methacrylate, phenyl methacrylate, 2-hydroxyethyl methacrylate, 2-hydroxypropyl methacrylate. Methacrylic acid esters such as dimethylaminoethyl methacrylate, glycidyl methacrylate, and stearyl methacrylate.
In addition to the above-mentioned monomers, a small amount of other monomers such as acrylonitrile and 2-
Vinyl pyridine, 4-vinyl pyridine, vinyl carbazole, vinyl methyl ether, butadiene, isobrene, maleic anhydride, maleic acid, maleic acid monoesters, maleic acid diesters, vinyl acetate and the like may be used.

Examples of the cross-linking agent used for forming the binder resin include divinylbenzene, bis (4-acryloxypolyethoxyphenyl) propane, and bifunctional cross-linking agents.
Ethylene glycol diacrylate, 1,3-butylene glycol diacrylate, 1,4-butanediol diacrylate, 1,5-pentanediol diacrylate, 1,6-hexanediol diacrylate, neopentyl glycol diacrylate, diethylene glycol diacrylate , Triethylene glycol diacrylate, tetraethylene glycol diacrylate, polyethylene glycol # 200, # 400, # 600 diacrylate, dipropylene glycol diacrylate, polypropylene glycol diacrylate, polyester type diacrylate (MANDA Nippon Kayaku), And those obtained by replacing the above acrylates with methacrylates.

As a polyfunctional crosslinking agent, pentaerythritol triacrylate, trimethylolethane triacrylate, trimethylolpropane triacrylate, tetramethylolmethane tetraacrylate, oligoester acrylate and its methacrylate, 2,2-bis (4-methacryloxy, poly Ethoxyphenyl) propane, diallyl phthalate, triallyl cyanurate,
Examples thereof include triallyl assocyanurate, triallyl isocyanurate, triallyl trimellitate, and diaryl chlorendate.

The method for synthesizing the binder resin according to the present invention is TH
The suspension polymerization method is preferable for adjusting the F insoluble content, but a method of basically synthesizing two or more kinds of polymers is preferable for adjusting the molecular weight distribution.

That is, a resin composition containing a crosslinkable region component in which a first polymer which is soluble in THF and soluble in a polymerizable monomer is dissolved in a polymerizable monomer containing a crosslinkable monomer and the monomer is polymerized. Is a way to get. In this case, since the former and latter polymers are uniformly mixed, when the resin is applied to the toner, the fixing and offset resistance are improved without impairing the durability, blocking resistance, etc. of the toner. It is possible.

The first polymer soluble in THF is preferably solution polymerized or ionic polymerized, and the second polymer for producing a component insoluble in THF is prepared by dissolving the first polymer. It is preferable to synthesize by suspension polymerization or bulk polymerization in the presence of a crosslinkable monomer under certain conditions. The first polymer is a polymerizable monomer 100 for forming the second polymer.
10-120 parts by weight (preferably 20-)
It is preferable to use 100 parts by weight).

The toner using a styrene resin may contain the following compounds in a proportion smaller than the content of the styrene resin component, as long as the effect of the present invention is not adversely affected.

For example, silicone resin, polyester,
Polyurethane, polyamide, epoxy resin, polyvinyl butyral, rosin, modified rosin, terpene resin, phenol resin, aliphatic or alicyclic hydrocarbon resin such as low molecular weight polyethylene or low molecular weight polypropylene, aromatic petroleum resin, chlorinated paraffin, For example, paraffin wax.

As the colorant contained in the toner used in the present invention, generally known dyes and pigments can be used. Examples of such dyes and pigments include carbon black, nigrosine dye, lamp black, Sudan Black SM, First Yellow G, Benzidine Yellow, Pigment Yellow, India First Orange, Irgadine Red, Paranitroaniline. Red, Toluidine Red, Carmine FB, Permanent Bordeaux FRR, Pigment Orange R, Resor Red 2
G, Rake 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 GG, Zapon Fast Orange RR, Oil Scarlet, Sumiplast Orange G, Orazol Brown B, Zapon Fast Scarlet CG, Aizenspiron Red BEH, Oil Pink OP, etc. are applicable. These colorants are preferably added in a proportion of 5 to 20% by weight with respect to the binder resin.

In the case of a magnetic toner, the magnetic fine particles which also have a role as a colorant include a metal made of a ferromagnetic element such as ferrite, magnetite or other iron, cobalt, nickel, or an alloy or compound containing the same. Alternatively, an alloy that does not contain a strong magnetic element, but becomes ferromagnetic by proper heat treatment, for example, a Heusler alloy containing manganese and copper such as manganese-copper-aluminum or manganese-copper-tin. Mention may be made of alloys of the type referred to, or chromium dioxide, and the like. The content ratio of the fine powder of the magnetic substance is 10
The amount is preferably 30 to 150 parts by weight, more preferably 40 to 100 parts by weight, based on 0 parts by weight.

The toner may contain a charge control agent, and a positive or negative charge control agent is used as the charge control agent. As the positive charge control agent, generally, nigrosine, an azine dye containing an alkyl group having 2 to 16 carbon atoms (Japanese Patent Publication No. 42-1627), and a basic dye (for example, C.I.
Basic Yellow 2 (C.I. 4100)
0), C.I. I. Basic Yellow 3, C.I.
I. Basic Red 1 (C.I. 45160),
C. I. Basic Red 9 (C.I. 4250
0), C.I. I. Basic Violet 1 (C.
I. 42535), C.I. I. Basic Violet
3 (C.I. 42555), C.I. I. BasicVi
olet 10 (C.I. 45170), C.I. I. Ba
sic Violet 14 (C.I. 42510),
C. I. Basic Blue 1 (C.I. 4202
5), C.I. I. Basic Blue 3 (C.I. 5
1005), C.I. I. Basic Blue 5 (C.
I. 42140), C.I. I. Basic Blue 7
(C.I. 42595), C.I. I. Basic Blu
e 9 (C.I. 52015), C.I. I. Basic
Blue 24 (C.I. 52030), C.I. I. Ba
sic Blue 25 (C.I. 52025), C.I.
I. Basic Blue 26 (C.I. 4402)
5), C.I. I. Basic Green 1 (C.I.4
2040), C.I. I. Basic Green 4
(C.I. 42000) and the like, lake pigments of these basic dyes (as a laker, phosphotungstic acid,
Phosphomolybdic acid, phosphotungsten molybdic acid, tannic acid, lauric acid, gallic acid, ferricyanide,
Ferrocyanide), C.I. I. Sovent Bl
ack 3 (C.I.26150), Hansa Yellow G
(C.I. 11680), C.I. I. Mordant
Black11, C.I. I. Pigment Black
1 etc. are mentioned.

Or, for example, a quaternary ammonium salt such as benzolmethyl-hexadecyl ammonium chloride or decyl-trimethyl ammonium chloride or a vinyl resin containing an amino group, a polyamide resin such as a condensation polymer containing an amino group, etc. may be mentioned. ,
Preferred examples include nigrosine, quaternary ammonium salts, triphenylmethane-based nitrogen-containing compounds and polyamides.

Further, as a negative charge control agent, Japanese Patent Publication No.
No. 20153, No. 42-27596, No. 4
Metal complexes of monoazo dyes described in JP-A Nos. 4-6397 and 45-26478, and further, nitramic acid and salts thereof described in JP-A-50-133338 or C.I. I. Dyes and pigments such as 14645, JP-B-55-42752, JP-B-58-41
No. 508, Japanese Patent Publication No. 58-7384, Japanese Patent Publication No. 5
9-7385 and the like salicylic acid,
Naphthoic acid, dicarboxylic acid Zn, Al, Co, C
Examples thereof include metal complexes of r, Fe and the like, sulfonated copper phthalocyanine pigments, nitro groups, halogen-introduced styrene oligomers and chlorinated paraffins. Particularly, from the viewpoint of dispersibility, metal complex salts of monoazo dyes, metal complexes of salicylic acid, alkylsalicylic acid, naphthoic acid, and dicarboxylic acid are preferable. The amount of these charge control agents added is such that, while maintaining good triboelectric chargeability as described above, it minimizes adverse effects such as a reduction in developing power and a reduction in environmental stability due to contamination of the developing sleeve surface by the charge control agents. In order to suppress it, the addition amount of 0.1 to 3 parts by weight is preferable with respect to 100 parts by weight of the binder resin.

An ethylene-based olefin polymer may be used in the toner as a fixing aid together with a binder resin.

The ethylene-based olefin homopolymer or ethylene-based olefin copolymer used herein includes polyethylene, polypropylene, ethylene-propylene copolymer, ethylene-vinyl acetate copolymer, ethylene-ethyl acrylate copolymer. There are coalesced products, ionomers having a polyethylene skeleton, and the like, and the above copolymer preferably contains 50 mol% or more (more preferably 60 mol% or more) of an olefin monomer.

Next, the image forming method of the present invention will be described.

In the step of developing the electrostatic charge image with toner, the magnetic brush method, the cascade developing method, the powder cloud method, and the conductive method described in US Pat. No. 3,909,258 are used. Method using magnetic toner, JP-A-53-
There is a method using a high-resistance magnetic toner described in Japanese Patent No. 31136. It is also suitable for an image forming method using a one-component developer. In the step of transferring the developed image to the transferred member, an electrostatic transfer method such as a corona transfer method or a bias application method to the contact transfer member is used.

Since a method of charging and / or transfer and / or charge elimination using corona discharge from a member which is not in contact with the photosensitive member onto the photosensitive member involves generation of ozone, a member which directly contacts the photosensitive member is used. There is a contact charging method in which a bias is applied through (that is, contact charging means). In such a method, the activated carbon filter, which is often attached to the conventional copying machine / printer, may be removed. In that case, the toner used in the present invention exhibits a remarkable effect. It is a thing.

Further, a blade cleaning method, a fur brush cleaning method or the like is applied to the step of removing the residual toner on the photosensitive layer or the insulating layer of the photosensitive member, and the blade cleaning method is particularly suitable.

Further, the toner image on the member to be transferred needs to be fixed on the member. As a means for this, a heat fixing means, a flash heat fixing means and the like can be used. Some heating roller fixing means are suitable.

[0062]

EXAMPLES The present invention will now be described in more detail by way of examples, which should not be construed as limiting the invention.

The number of copies and% described in the examples are
All parts by weight and% by weight are shown.

Synthesis Example 1 200 parts of cumene was placed in a reactor and heated to the reflux temperature. Add 100 parts of styrene monomer and di-ter
A mixture of 8 parts of t-butyl peroxide was added dropwise under reflux of cumene over 4 hours. Further under cumene reflux (146 ° C
Polymerization was completed at ~ 156 ° C) and cumene was removed. The polystyrene obtained was dissolved in THF and had Mw = 3700,
Mw / Mn = 2.64, the molecular weight where the main peak of GPC was located was 3500, and Tg = 57 ° C.

30 parts of the above polystyrene was dissolved in the following monomer mixture to obtain a mixed solution.

Monomer mixture Blend ratio Styrene monomer 54 parts N-butyl acrylate monomer 16 parts Divinylbenzene 0.3 parts Benzoyl peroxide 1.3 parts

170 parts of water in which 0.1 part of the partially saponified polyvinyl alcohol was dissolved was added to the above mixed solution to prepare a suspension dispersion. 15 parts of water was put thereinto, a nitrogen gas introducing pipe was introduced into the water, and the nitrogen gas was sufficiently introduced into the water. The above-mentioned dispersion liquid was added to the reactor under a nitrogen gas atmosphere, and the reaction temperature was 70-
The suspension polymerization reaction was carried out at 95 ° C. for 9 hours. After completion of the reaction, filtration, dehydration and drying were carried out to obtain a resin composition of polystyrene and a styrene-n-butyl acrylate copolymer. In this composition, the THF insoluble matter and the THF soluble matter were uniformly mixed, and the polystyrene and the styrene-n-butyl acrylate copolymer were uniformly mixed. About 0.5 g of the obtained resin composition (using a resin composition powder of 24 mesh pass, 60 mesh on) was precisely weighed and made into a cylindrical filter paper N made of Toyo Roshi Kaisha.
o. Put it in 86R (diameter 28 mm, length 100 mm),
200 ml of THF is refluxed once every 4 minutes for TH
The F insoluble matter was measured. The THF insoluble content of the resin composition is 2
5%. Further, when the molecular weight distribution of the THF-soluble component was measured, it had peaks at the positions of 40,000 and 34,000,
Mn = 0.550,000, Mw = 130,000, Mw / Mn = 24,
A molecular weight of 10,000 or less was 25%. Furthermore, the Tg of the resin composition was 58 ° C.

Synthesis Example 2 200 parts of cumene was placed in a reactor and heated to the reflux temperature. The following mixture was added dropwise under cumene reflux for 4 hours.

Monomer mixture Compounding ratio Styrene monomer 95 parts α-methylstyrene monomer 5 parts Di-tert-butyl peroxide 8 parts

Further, the polymerization was completed under cumene reflux (146 to 156 ° C.) to remove cumene. Obtained styrene-
The α-methylstyrene copolymer has Mw = 4500, Mw
/Mn=2.8, molecular weight 44 on GPC chart
It had a main peak at position 00 and had a Tg of 63 ° C.

30 parts of the styrene-α-methylstyrene copolymer was dissolved in the following monomer mixture to give a mixed solution.

Monomer mixture Blend ratio Styrene monomer 55 parts 2-Ethylhexyl acrylate 15 parts Divinylbenzene 0.3 parts Benzoyl peroxide 1.3 parts

170 parts of water in which 0.1 part of a partially saponified polyvinyl alcohol was dissolved was added to the above mixed solution to prepare a suspension dispersion. Add 15 parts of water, and in the same manner as in Synthesis Example 1,
After sufficiently flowing nitrogen, the above dispersion liquid was added to the reactor and reacted at a reaction temperature of 70 to 95 ° C. for 9 hours. After the reaction,
After filtration, dehydration and drying, a composition of a styrene-α-methylstyrene copolymer and a styrene-2-ethylhexyl acrylate copolymer was obtained.

The THF insoluble content of this resin composition was 32%.
Met. Further, when the molecular weight distribution of the THF soluble component was measured, it had peaks at the molecular weights of 55,000 and 42,000, and Mn = 0.620000, Mw = 130,000, Mw / Mn = 2.
1, the molecular weight of 10,000 or less was 20%. The Tg of the resin composition was 58 ° C.

Synthesis Example 3 200 parts of cumene was placed in a reactor and heated to the reflux temperature. The following mixture was added dropwise under cumene reflux for 4 hours.

Monomer mixture Blending ratio Styrene monomer 90 parts Methyl methacrylate monomer 10 parts Di-tert-butyl peroxide 8 parts

Polymerization was further completed under cumene reflux (146 to 156 ° C.) to remove cumene. Obtained styrene-
The methacrylate copolymer has Mw = 3900, Mw /
It had a main peak at the position of Mn = 2.6 and molecular weight 4100 and had Tg = 60 ° C.

40 parts of the styrene-methyl methacrylate copolymer was dissolved in the following monomer mixture to give a mixed solution.

Monomer mixture Blending ratio Styrene monomer 38 parts N-butyl methacrylate monomer 22 parts Divinylbenzene 0.24 part Benzoyl peroxide 0.60 part tert-Butylperoxy 2-ethylhexanoate 0.80 part

170 parts of water in which 0.1 part of a partially saponified polyvinyl alcohol was dissolved was added to the above mixed solution to prepare a suspension dispersion. After adding 15 parts of water and sufficiently passing nitrogen gas in the same manner as in Synthesis Example 1, the above dispersion liquid was added to the reactor,
The reaction was carried out at a reaction temperature of 70 to 95 ° C. for 9 hours. After completion of the reaction, filtration, dehydration and drying were carried out to obtain a resin composition of a styrene-methylmethacrylate copolymer and a styrene-n-butylmethacrylate copolymer.

The THF insoluble content of this resin composition was 35%.
Met. Further, when the molecular weight distribution of the THF-soluble component was measured, it had peaks at 40,000 and 43,000, and Mn = 0.
590,000, Mw = 920,000, Mw / Mn = 16, molecular weight 1
It was 32% or less. Furthermore, the Tg of the resin composition is
It was 60 ° C.

Synthesis Example 4 Monomer mixture Compounding ratio Styrene monomer 55 parts N-butyl acrylate monomer 15 parts Divinylbenzene 0.14 parts tert-Butylperoxy 2-ethylhexanoate 1.5 parts

170 parts of water in which 0.1 part of a partially saponified polyvinyl alcohol was dissolved was added to the above mixture to give a suspension dispersion. After 15 parts of water was added and nitrogen gas was sufficiently passed in the same manner as in Synthesis Example 1, the above dispersion liquid was added to the reactor and reacted at a reaction temperature of 70 to 95 ° C. for 9 hours. After the reaction,
It was filtered, dehydrated and dried to obtain a resin composition of styrene-n-butyl acrylate copolymer.

The THF insoluble content of this resin composition was 44%.
Met. Further, when the molecular weight distribution of the THF-soluble component was measured, it had a peak at the position of molecular weight of 20,000, and Mn =
21% was 80,000, Mw = 280,000, Mw / Mn = 3.5, and a molecular weight of 10,000 or less. Furthermore, the Tg of the resin composition
Was 56 ° C.

Comparative Synthesis Example 1 200 parts of cumene was placed in a reactor and heated to the reflux temperature. Add 100 parts of styrene monomer and di-tert.
A mixture of 8 parts of -butyl peroxide was added dropwise under reflux of cumene over 4 hours. Further under cumene reflux (146 ° C ~
Polymerization was completed at 156 ° C) to remove cumene. The obtained polystyrene was dissolved in THF and had Mw = 3700, Mw /
Mn = 2.64, the molecular weight where the main peak of GPC was located was 3500, and Tg = 57 ° C.

30 parts of the above polystyrene was dissolved in the following monomer mixture to prepare a mixed solution.

Monomer mixture Blending ratio Styrene monomer 54 parts N-butyl acrylate monomer 16 parts Divinylbenzene 0.3 parts Benzoyl peroxide 1.3 parts

170 parts of water in which 0.1 part of a partially saponified polyvinyl alcohol was dissolved was added to the above mixed solution to prepare a suspension dispersion. Add 15 parts of water and add the above dispersion liquid to the reactor without passing nitrogen gas into the water.
The suspension polymerization reaction was carried out at ˜95 ° C. for 9 hours. After completion of the reaction, filtration, dehydration and drying were carried out to obtain a resin composition of polystyrene and a styrene-n-butyl acrylate copolymer.

Comparative Synthesis Example 2 200 parts of cumene was placed in a reactor and heated to the reflux temperature. Add 100 parts of styrene monomer and di-tert.
A mixture of 8 parts of -butyl peroxide was added dropwise under reflux of cumene over 4 hours. Further under cumene reflux (146 ° C ~
Polymerization was completed at 156 ° C) to remove cumene. The polystyrene obtained was dissolved in THF and had Mw = 3700, Mw
/Mn=2.64, the molecular weight where the main peak of GPC was located was 3500, and Tg = 57 ° C.

30 parts of the above polystyrene was dissolved in the following monomer mixture to obtain a mixed solution.

Monomer mixture Blending ratio Styrene monomer 54 parts N-butyl acrylate monomer 16 parts Divinylbenzene 0.3 parts Benzoyl peroxide 1.3 parts

170 parts of water in which 0.1 part of a partially saponified polyvinyl alcohol was dissolved was added to the above mixed solution to prepare a suspension dispersion. Add 15 parts of water, add the above dispersion to a reactor in which the atmosphere in the container is simply replaced with nitrogen gas without introducing nitrogen gas into the water, and carry out a suspension polymerization reaction at a reaction temperature of 70 to 95 ° C. for 6 hours. It was After completion of the reaction, filtration, dehydration,
After drying, a resin composition of polystyrene and a styrene-n-butyl acrylate copolymer was obtained.

Example 1 Binder resin (resin composition of Synthesis Example 1) 100 parts Colorant (magnetite particles, average particle size 0.3 μm) 60 parts Low molecular weight polypropylene 3 parts Negatively chargeable monoazo dye 1 part

After the above raw materials were mixed, they were heat-melted and kneaded by an extruder at a temperature of 120 ° C., cooled, pulverized and classified to obtain a negatively charged magnetic toner having a volume average particle diameter of 11 μm. 100 parts of negatively charged magnetic toner, 0.4 negatively charged colodal silica
Part was added externally to prepare a magnetic toner having silica on the surface of toner particles. In order to prevent the generation of ozone, the corona charger was modified into a contact charging roller as shown in FIG. 1 to remove the ozone filter, and the laser beam printer LBP-SX modified by Canon (OPC photosensitive drum and heating / pressurizing roller means was provided. ), The OPC photosensitive drum is charged by the contact charging roller to which the bias voltage is applied, the electrostatic charge image is formed by the laser beam, the solid black image is formed by the magnetic toner, and the solid black image is transferred to the plain paper. And temperature 1
The image was fixed under heat and pressure at 80 ° C. Then, continuous printing was performed, and the odor generated at that time was observed.

The odor was evaluated by installing the above printer in the center of a small room measuring about 3 m square, printing it out, and randomly selecting 10 people around it, sniffing the odor while gradually changing the position. No feeling ... ○ Slight odor is not a problem ... △ Smelling and worrisome ... × A so-called panel test type test was performed to determine whether it was. As a result, extremely good results were obtained, and it was determined that there was no problem with odor (see Table 1).

As a result of analyzing the toner, the amount of benzaldehyde that should be generated by the oxidation of the styrene monomer was 0.002% or less.

Example 2 A magnetic toner was prepared and evaluated in the same manner as in Example 1 except that the binder resin used in Example 2 was changed to the resin composition of Synthesis Example 2, and similarly good results were obtained. Was given.

The content of benzaldehyde in the toner was 0.003%.

Example 3 Example 1 was repeated except that the binder resin used was changed to the resin composition of Synthesis Example 3 and the hot melt kneading temperature of the extruder was set to 100 ° C.
When a magnetic toner was prepared and evaluated in the same manner as above, many people felt a slight odor, but it was determined that there was no particular problem.

The amount of benzaldehyde in the toner at that time was 0.005%.

Example 4 A magnetic toner was prepared and evaluated in the same manner as in Example 1 except that the binder resin used in Example 4 was changed to the resin composition of Synthesis Example 4. The obtained solid black image was practical. Although within the range, the fixing property was slightly inferior, but similarly good results were obtained with respect to odor.

The amount of benzaldehyde in the toner is 0.00
It was 3%.

A corona charger of the printer LBP-SX was left as it was, and the same procedure as in Example 1 was carried out except that only the ozone filter was removed. Almost no aldehyde odor was pointed out, but the ozone odor was used instead. Many people felt that.

Comparative Example 1 The procedure of Example 1 was repeated except that the resin composition of Comparative Synthesis Example 1 was used instead of the binder resin used. As a result, many people were concerned about the odor and it was judged as NG.

The amount of benzaldehyde in the toner at that time was 0.009%.

Comparative Example 2 A magnetic toner was prepared and evaluated in the same manner as in Example 1 except that the binder resin used in Comparative Example 2 was changed to the resin composition of Comparative Synthesis Example 2. Was determined.

The amount of benzaldehyde in the toner at that time was 0.007% by weight.

The results of the odor panel test conducted in Examples and Comparative Examples are summarized below.

[0109]

[Table 1]

[0110]

The image forming method of the present invention has an improved odor problem, and it is possible to remove the ozone filter from the image forming apparatus.

[Brief description of drawings]

FIG. 1 is a diagram showing a contact charging roller of a modified laser beam printer used in Examples and Comparative Examples.

[Explanation of symbols]

 1 charging roller having a conductive rubber layer 2 photoconductor drum 3 high voltage power supply for charging

 ─────────────────────────────────────────────────── ─── Continued front page (72) Inventor Eiichi Imai 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc. (72) Seiichi Takagi 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Within the corporation

Claims (6)

[Claims] 1. A charging step of charging a photoreceptor with a contact charging means to which a bias is applied, an electrostatic charge image forming step of forming an electrostatic charge image on the charged photoreceptor, and an electrostatic charge image of the photoreceptor at least. An image forming method comprising at least a developing step of developing with a toner containing a binder resin and a colorant to form a toner image on a photoconductor, and a step of fixing a toner image on a transfer material by a heat fixing means. The image forming method, wherein the toner has a benzaldehyde content of 0.005% by weight or less and the binder resin is a styrene resin. 2. The image forming method according to claim 1, wherein the contact charging means is a contact charging roller. 3. The image forming method according to claim 1, wherein the heat fixing unit is a heat roller fixing unit. 4. The binder resin is a styrene resin, and in a chromatogram of the binder resin by GPC, the ratio (M) of the weight average molecular weight (Mw) to the number average molecular weight (Mn).
w / Mn) is 5 or more, and 10 to 50% by weight of a component having a molecular weight of 10,000 or less is contained.
The image forming method according to any one of 1. 5. The image forming method according to claim 1, wherein the styrene resin is a resin prepared by a suspension polymerization method. 6. The resin composition according to claim 1, wherein the styrene resin is a resin composition having a styrene resin prepared by a solution polymerization method and a styrene resin prepared by a suspension polymerization method. Image forming method.