JP2850074B2 - Image forming method - Google Patents

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 such as an electrophotographic method, an electrostatic recording method, and an electrostatic printing method.
Using a photosensitive member made of an organic semiconductor material containing fine particles of a fluorine-containing resin, a contact charging step in which a charging member to which an externally applied voltage is applied is brought into contact with the photosensitive member to perform charging, and a transfer member to which an externally applied voltage is applied. And a contact transfer step of performing electrostatic transfer while pressing on a transfer material.

[0002]

2. Description of the Related Art Conventionally, as an electrophotographic method, US Pat.
Numerous methods are known as described in Japanese Patent Publication No. 297691, Japanese Patent Publication No. 42-23910 and Japanese Patent Publication No. 43-24748, but generally, a photoconductive substance is used and various methods are used. An electric latent image is formed on the photoreceptor, and then the latent image is developed using toner, and if necessary, a toner image is transferred to a transfer material such as paper.
The copy is obtained by fixing with pressure, heat and pressure, or solvent vapor, etc., and the residual developer remaining without being transferred onto the photoreceptor is removed by various methods, and the above-described steps are repeated.

[0003] In recent years, such a copying apparatus has been used as an information output device connected to another information processing machine by the introduction of digital technology, or as a multifunctional device, not merely as a copying machine for office work for copying an original. As a result, the processing and editing of image information became easy, and the image information began to be used as a copying machine for creating a new original document and as a personal copy for individuals.

Therefore, higher speed, higher image quality, smaller size and lighter weight have been pursued, and higher reliability has been strictly pursued.

In such a situation, a corona charging device has been widely used as a means for charging a surface of a photosensitive member as a member to be charged in a printer or a copying machine using an electrophotographic technique. The corona charging device is effective as a means for uniformly charging the surface of the photoreceptor to a predetermined potential, but has problems such as requiring a high-voltage power supply and generating a large amount of ozone.

For such a corona charging device, a contact charging device for charging a photosensitive member by bringing a charging member (for example, a conductive elastic roller or a blade) into contact with the photosensitive member to which a voltage is applied, for example, Japanese Patent Application Laid-Open Publication No. An apparatus such as that disclosed in JP-A-63-149669 has advantages such as a low power supply voltage and an extremely small amount of ozone generated. Therefore, instead of a corona charging device, an image carrier such as a photoconductor or a dielectric material is used. It is being put to practical use as a means for treating the surface of a body or other charged object.

In the transfer apparatus, instead of the transfer means using corona discharge which has been widely used in the past, a voltage is applied to the photosensitive member which travels endlessly such as a rotating cylinder or an endless belt. A transfer member (for example, a conductive elastic roller) is pressed against the photoreceptor so that the transfer material passes between the two, and the toner image on the photoreceptor side is transferred to the transfer material. −123385
A contact transfer device as disclosed in Japanese Patent Application Laid-Open Publication No. H11-163,813 has been proposed. Compared to a transfer device using corona discharge, this contact transfer device can reduce the power supply voltage, generate a small amount of ozone, and adjust the pressing force of the transfer member against the photosensitive member to adjust the photosensitive material of the transfer material. The area of adsorption to the body can be enlarged, and the transfer material can be positively supported at the transfer site. For this reason, there is little possibility that transfer failure due to transfer failure due to transfer material conveyance means or a loop or curl existing in the transfer material will occur, and the transfer material conveyance path will be shortened and the diameter of the photoconductor will be reduced due to the downsizing of the image forming apparatus. It has the advantage that it can easily deal with such requests.

Further, an example of an image forming method having the contact charging method and the contact transfer method will be described with reference to the schematic configuration diagram of FIG. For convenience of explanation, the charging member is a charging roller,
The transfer member will be described as a transfer roller.

Reference numeral 1 denotes a rotating drum type electrostatic image carrier (hereinafter, referred to as a photoconductor). The photoconductor 1 includes a conductive substrate 1b made of aluminum or the like and a photoconductive layer 1 formed on the outer surface thereof.
a is a basic constituent layer, and is rotated at a predetermined peripheral speed (process speed) clockwise in the drawing.

Reference numeral 2 denotes a charging roller serving as a charging member;
The basic configuration includes a central metal core 2b and a conductive elastic layer forming the outer periphery thereof. The charging roller 2 is pressed against the surface of the photoconductor 1 with a predetermined pressing pressure, and is driven to rotate as the photoconductor 1 rotates.

Reference numeral 3 denotes a charging bias power supply for applying a voltage to the charging roller 2. By applying a bias to the charging roller, the surface potential of the photoconductor 1 is charged to a predetermined polarity and potential.

Next, an electrostatic latent image is formed by the image exposure 4 and is sequentially visualized as a toner image by the developing means 5.

A transfer roller 6 is a transfer member.
A center metal core 6b and a conductive elastic layer 6a forming the outer periphery thereof
And the basic configuration. The transfer roller 6 is pressed against the surface of the photoconductor 1 with a predetermined pressing pressure and rotates.

The transfer material 8 is conveyed between the photoreceptor 1 and the transfer roller 6, and at the same time, a bias having a polarity opposite to that of the toner is applied to the transfer roller 6 from a transfer bias power supply 7. The image is transferred to the front side of the transfer material 8.

Next, the transfer material 8 is conveyed to a fixing device 11 having a heating roller 11a containing a halogen heater therein and an elastic pressure roller 11b pressed against the roller 11a with a pressing force. And 11b, the toner image is fixed on the transfer material 8 and discharged as an image formed product.

On the surface of the photoreceptor 1 after the transfer of the toner image, adhered contaminants such as residual developer after transfer are cleaned and cleaned by a cleaning device 9 having an elastic cleaning blade pressed against the photoreceptor 1 in a counter direction. Further, the charge is removed by the charge removing exposure device 10 to repeatedly form an image.

As described above, in the image forming method having such a contact charging and contact transfer method, compared with the corona charging / transfer method, the photosensitive member can be uniformly charged with a relatively low voltage bias and a sufficient charge can be obtained. Transfer becomes possible, miniaturization of the device itself,
It is excellent in suppressing corona discharge products such as ozone.

However, in the above-mentioned image forming method using the contact charging method and the contact transfer method, a fluidity imparting agent such as silica is added to toner particles comprising a binder resin and a colorant such as a magnetic material. When a general developer is used, the residual developer that cannot be completely removed in the cleaning process after transfer slightly exists on the surface of the photosensitive member, and the residual developer has a predetermined pressing contact pressure, and Is pressed against and fixed to the surface of the charging roller and the surface of the photoreceptor by the charging roller in contact with
As the number of copies increases, the toner adheres and accumulates more strongly, causing contamination of the charging roller, filming of the photoconductor, and fusion of the toner. Further, if the charging roller and the photosensitive member cannot be kept in sufficient contact with each other due to charging roller contamination or toner fusion, problems such as poor charging may occur.

Further, in an apparatus that performs transfer by contact, a transfer current is supplied from the contact portion, so it is necessary to apply a certain pressure to the transfer device. Pressure is also applied to the toner image on the latent image on the photoconductor, causing toner aggregation. As a result, the toner easily adheres to the surface of the photoreceptor and the surface of the contact member of the transfer device, and filming and toner fusion occur. Due to these, poor charging, poor cleaning, and poor transfer occur, and the obtained image has a problem that image density is reduced, and a white spot pattern in a solid black image and a black spot pattern in a solid white image are easily generated. is there.

As a method for removing the residual developer after the transfer on the photoreceptor, there are known methods such as a blade method, a fur brush method, and a magnetic brush method. It is not currently possible to completely remove the remaining residual developer.

As the photoreceptor, a photoreceptor made of an organic semiconductor material is generally used to reduce the size and cost of a copying apparatus. Conventional photoconductors made of organic semiconductor materials have poor mechanical durability. As a result, using a developer containing an abrasive component, for example, a developer as disclosed in Japanese Patent Application Laid-Open No. 60-32060, makes the photoconductor durable in the cleaner portion. At the same time, the surface of the photoreceptor was appropriately shaved, and a new photoreceptor surface always appeared, so that problems such as filming and toner fusion hardly occurred. However, in order to extend the durability life of the photoconductor, the lubricant was dispersed in the photoconductor surface layer to improve the mechanical durability of the photoconductor surface layer. This markedly decreased, and a highly durable photoreceptor was put to practical use as disclosed in, for example, JP-A-63-30850.

In JP-A-63-30850, lubricating resin powders such as fluorine resin fine particles, polyolefin resin powder, silicone resin powder, etc. And carbon fluoride, etc., dramatically improve the mechanical durability of the photoreceptor surface layer, and at the same time, improve the lubricity to prevent mechanical damage such as abrasion and scratches during cleaning. And so on. Further, at the same time, the oxidation potential is 0.6 V
By using the above-described charge transporting material, an effect of preventing the photoconductor surface layer from being oxidized and deteriorated by ozone or the like is realized.

The highly durable photoreceptor can suppress generation of ozone products in an image forming method including a transfer step and charging by corona discharge, which has been widely used in the past. Stable high durability and good cleaning properties were exhibited without occurrence of adhesion and the like.

However, when the highly durable photoreceptor is used in an image forming method including a contact charging step and a contact transfer step without using the corona discharge, the charging roller and the transfer roller are exposed to pressure by pressing pressure. Since the residual developer and the toner image developed on the latent image are pressed against the surface of the body and pressed against the surface of the photoconductor and the surfaces of the respective contact members, filming and toner fusion are likely to occur. In addition, since the photoreceptor surface layer has high mechanical durability, the amount of shaving of the photoreceptor surface layer due to durability is small, and the filming that occurs and the toner fusion layer cannot be scraped off. Ming and toner fusion occurred.

As described above, in an image forming method including a highly durable photoreceptor, a contact charging step and a contact transfer step, the filming resistance and the filming resistance while maintaining the mechanically high durability of the photoreceptor are maintained. At present, there is no image forming method for realizing toner fusion resistance, that is, high cleaning property.

[0026]

SUMMARY OF THE INVENTION It is an object of the present invention to provide an image forming method using a highly durable photoreceptor, a contact charging method and a contact transfer method, which solves the above-mentioned problems. .

An object of the present invention is to prevent the adhesion of paper dust and various products to the surface of a photoreceptor and the fixation of developer components such as filming and toner fusion, and to form an image in which a stable copy image is always obtained. It provides a method.

An object of the present invention is to prevent the toner component from sticking to the surface of the charging member, thereby sufficiently maintaining the contact between the charging member and the photosensitive member, and preventing the charging process from causing charging failure such as uneven charging. And an image forming method having the following.

An object of the present invention is to provide an image forming method having a transfer step of preventing the occurrence of image defects and preventing the occurrence of image defects by preventing the toner component from sticking to the transfer member surface. is there.

[0030]

According to the present invention, a charging member to which a voltage is applied is brought into contact with a photoreceptor having an organic semiconductor material (preferably, a photoreceptor having a surface layer containing fine particles of fluorine-containing resin). Charge the photoreceptor to expose the photoreceptor to form an electrostatic latent image, the formed electrostatic latent image,
Fluidizing agent, the weight average particle diameter (m-D ₄₎ is 0.6 to 5
μm, and the number average particle diameter (m−D ₁ ) is 0.5 to 4 μm.
m, and the ratio of (m−D ₄ ) / (m−D ₁ ) is 1.0 to
A magnetic toner image is formed by developing with a magnetic developer containing a metal oxide powder and a magnetic toner of 2.4, and the toner image is transferred from the photoreceptor to a transfer material with a linear pressure of 3 g / cm.

As described above, it is impossible at present to completely remove the residual developer on the photoreceptor after transfer with a cleaner of a blade type, a fur brush type, a magnetic brush type, etc. The developer or the like is pressed against the charging member (or the transfer member) which is in contact with the photoreceptor, and is easily fixed. The photoreceptor is made of an organic semiconductor material containing a fluorine-containing resin fine particle in a surface layer. Surface layer is very excellent in mechanical durability, so that even when a toner containing a metal oxide powder or the like as an abrasive is used, only a small polishing effect can be obtained in the cleaner portion, For example, in order to realize filming and fusion resistance and obtain a high-quality image, an image forming method having a new photosensitive member cleaning method is required.

The present inventors have conducted various studies to find a highly durable photoreceptor, a metal oxide as a toner as a new cleaning method of the photoreceptor in an image forming method including a contact charging step and a contact transfer step. The transfer member rubs the surface of the photoreceptor between the papers by using a material containing an abrasive component such as material powder to make the peripheral speed of the photoreceptor and the transfer member different, thereby cleaning the surface of the photoreceptor. We found that measures to improve the performance were effective.

Further, as a result of a detailed study based on this means, the following was grasped. The transfer member that is in contact with the photoconductor is pressed against the photoconductor with a pressing pressure of a linear pressure of 3 g / cm or more. The peripheral speed difference between the photosensitive member and the transfer member is ± 0.1 to 5.0.
%, More preferably ± 0.5 to 2.0%.

It is important that the developer used satisfies the following components. Use a superplasticizer. The weight average particle size (m-D ₄ ) of the metal oxide powder is 0.6
And the number average particle diameter (m-D ₁ ) is 0.5 to 5 μm.
4 μm, and the ratio of (m−D ₄ ) / (m−D ₁ ) is 1.
0 to 2.4.

These are due to the following reasons. The contact pressure between the photosensitive member and the transfer member is 3 g / linear pressure.
cm or more. The linear pressure is calculated by the following formula. (Linear pressure) [g / cm] = (total pressure applied to transfer member)
[G] ÷ (length in contact) [cm] When the pressing pressure is less than 3 g / cm in linear pressure, the polishing effect on the surface of the photoreceptor is lost, and transfer deviation of the transfer material and transfer current are caused. This is not preferable because transfer failure due to shortage occurs. When the peripheral speed difference between the photoconductor and the transfer member is less than ± 0.5%, the polishing effect on the photoconductor surface becomes small, and
If less than 0.1%, no polishing effect is observed. On the other hand, if the peripheral speed difference exceeds ± 2.0%, scattering occurs in the copy image, causing a reduction in resolution and further ± 5.0.
%, It is not preferable because remarkable image deterioration is caused by a decrease in resolution and a scratch-like defect is generated on the surface of the photoreceptor. In the absence of a fluidizing agent, the fluidity of the magnetic toner used in the present invention is remarkably reduced, resulting in poor charging and a blocking phenomenon in a developing device. On the other hand, the absence of a fluidizing agent is not preferable because the fluidity of the waste developer in the cleaner portion is remarkably reduced, causing image deterioration due to poor cleaning or the like. A weight average particle diameter (m-D4) of 0.6 to ₅ m;
The number average particle diameter (m-D ₁ ) is 0.5 to 4 μm;
(M-D ₄₎ / Te is at the developer ratio containing a metal oxide powder is 1.0 to 2.4 of the (m-D _1), the metal oxide powder is mainly non-image portion Since the development is performed, there is a high probability that the photoconductor and the charging member are present on the photoconductor when the photoconductor and the charging member come into contact with each other between the papers, and the photoconductor surface layer can be efficiently polished.

When a metal oxide powder having a weight average particle size (m-D ₄ ) of more than 5 μm is used, the metal oxide powder is less likely to be independently developed in a white background inversion portion and is not consumed. As the metal oxide powder accumulates, a large amount of metal oxide powder is present on the developer carrying member, and the image quality of the copied image gradually decreases. Further, when the transfer roller rubs the surface of the photoconductor, a sharp scratch-like defect is generated on the surface of the photoconductor.

If the weight average particle size (m-D ₄ ) is smaller than 0.4 μm, slipping through the cleaner tends to occur, resulting in poor cleaning. In addition, it becomes easier to electrostatically and strongly adhere to the surface of the charging and transfer roller, and the cleaning property of each contact member surface is reduced.

If the ratio of (m-D ₄ ) / (m-D ₁ ) is more than 2.4, the particle size distribution becomes too wide, and the particles having too small or too coarse particles are often used. It is not preferred.

Further, the constitution of a developer which is preferable for achieving the object in the present invention will be described in detail below.

Examples of the binder resin used in the present invention include a vinyl resin, a polyester resin, and an epoxy resin. Among them, a vinyl resin and a polyester resin are preferable.

The following are examples of vinyl monomers for synthesizing vinyl resins.

For example, unsaturated dibasic acids such as maleic acid, citraconic acid, itaconic acid, alkenyl succinic acid, fumaric acid and mesaconic acid; maleic anhydride, citraconic anhydride, itaconic anhydride, alkenyl succinic anhydride Unsaturated dibasic acid anhydrides such as those; methyl maleate half ester, maleic acid ethyl half ester, maleic acid butyl half ester, citraconic acid methyl half ester, citraconic acid ethyl half ester, citraconic acid butyl half ester, methyl itaconate Half esters of unsaturated dibasic acids such as half ester, methyl alkenyl succinate half ester, methyl half fumarate ester and methyl half ester of mesaconic acid; and unsaturated dibasic acid esters such as dimethyl maleic acid and dimethyl fumaric acid. It is.

Acrylic acid, methacrylic acid, crotonic acid,
Α, β-unsaturated acids such as cinnamic acid; crotonic anhydride,
Α, β-unsaturated acid anhydrides such as cinnamic anhydride;
anhydrides of β-unsaturated acids and lower fatty acids; alkenyl malonic acid, alkenyl glutaric acid, alkenyl adipic acid,
These acid anhydrides and their monoesters are mentioned.

Further, examples of the comonomer of the vinyl copolymer include the following.

For example, styrene, o-methylstyrene, m
-Methylstyrene, p-methylstyrene, p-methoxystyrene, p-phenylstyrene, p-chlorostyrene, 3,4-dichlorostyrene, p-ethylstyrene,
2,4-dimethylstyrene, pn-butylstyrene,
styrene and its derivatives such as p-tert-butylstyrene, pn-hexylstyrene, pn-octylstyrene, pn-nonylstyrene, pn-decylstyrene, pn-dodecylstyrene; ethylene; Ethylenically unsaturated monoolefins such as propylene, butylene and isobutylene; unsaturated polyenes such as butadiene;
Vinyl halides such as vinyl chloride, vinylidene chloride, vinyl bromide and vinyl fluoride; vinyl ester acids such as vinyl acetate, vinyl propionate and vinyl benzoate; methyl methacrylate, ethyl methacrylate, propyl methacrylate, methacrylic acid α-methylene aliphatic monomers such as n-butyl, isobutyl methacrylate, n-octyl methacrylate, dodecyl methacrylate, 2-ethylhexyl methacrylate, stearyl methacrylate, phenyl methacrylate, dimethylaminoethyl methacrylate, diethylaminoethyl methacrylate Carboxylic esters;
Methyl acrylate, ethyl acrylate, acrylic acid n-
Butyl, isobutyl acrylate, propyl acrylate,
Acrylic esters such as n-octyl acrylate, dodecyl acrylate, 2-ethylhexyl acrylate, stearyl acrylate, 2-chloroethyl acrylate and phenyl acrylate; vinyl ethers such as vinyl methyl ether, vinyl ethyl ether and vinyl isobutyl ether Vinyl ketones such as vinyl methyl ketone, vinyl hexyl ketone and methyl isopropenyl ketone; N-vinyl pyrrole, N-vinyl carbazole, N
N- such as vinylindole and N-vinylpyrrolidone
Vinyl compounds; vinyl naphthalenes; acrylic acid or methacrylic acid derivatives such as acrylonitrile, methacrylonitrile, and acrylamide; esters of the above-mentioned α, β-unsaturated acids and diesters of dibasic acids. These vinyl monomers are used alone or in combination of two or more.

Of these, a combination of monomers that results in a styrene copolymer or a styrene-acrylic copolymer is preferred.

If necessary, the polymer may be cross-linked with a cross-linking monomer as exemplified below.

Examples of the aromatic divinyl compound include divinylbenzene and divinylnaphthalene; examples of the diacrylate compound linked by an alkyl chain include:
Ethylene glycol diacrylate, 1,3-butylene glycol diacrylate, 1,4-butanediol diacrylate, 1,5-pentanediol acrylate, 1,6-hexanediol diacrylate, neopentyl glycol diacrylate, and the above compounds Diacrylate compounds linked by an alkyl chain containing an ether bond, for example, diethylene glycol diacrylate, triethylene glycol diacrylate, tetraethylene glycol diacrylate, polyethylene glycol # 400 diacrylate, polyethylene glycol # 600 diacrylate, dipropylene glycol diacrylate, and methacrylate Include those obtained by changing the over preparative; e.g. diacrylate compounds linked with a chain containing an aromatic group and an ether bond, polyoxyethylene (2)
-2,2-bis (4-hydroxyphenyl) propane diacrylate, polyoxyethylene (4) -2,2-bis (4-hydroxyphenyl) propane diacrylate, and acrylates of the above compounds were replaced with methacrylates. And polyester-type diacrylate compounds, for example, trade name MANDA (Nippon Kayaku). Examples of polyfunctional crosslinking agents include pentaerythritol triacrylate, trimethylolethane triacrylate, trimethylolpropane triacrylate, tetramethylol methanetetraacrylate,
Oligoester acrylates and those obtained by replacing the acrylates of the above compounds with methacrylates; triallyl cyanurate, triallyl trimellitate;

These cross-linking agents may be used in combination with other monomer components 10
0.01 to 5% by weight (more preferably 0.03 to 3% by weight) can be used with respect to 0% by weight.

Examples of the initiator for polymerizing the monomer include t-butylperoxy-2-ethylhexaneate, t-butylperoxylaurate, benzoyl peroxide, lauroyl peroxide, octanoyl peroxide, -T-butyl peroxide, t-
Butylcumyl peroxide, diisopropylbenzene hydroperoxide, p-menthane hydroperoxide, 2,2′-azobisisobutyronitrile,
2,2 ′ azobis (2-methylbutyronitrile), 2,
A radical initiator such as 2'-azobis (4-methoxy-2,4-dimethylvaleronitrile) is used alone or in combination. The amount of the radical polymerization initiator used is suitably from 0.1 to 15% by weight, preferably from 1 to 10% by weight, based on the monomers constituting the low molecular weight polymer.

Further, as the initiator for polymerizing the monomer, a bifunctional radical initiator is preferably used. For example, 1,1-bis (t-butylperoxy) 3,3,5
-Trimethylcyclohexane, 1,1-bis (t-butylperoxy) cyclohexane, 1,4-bis (t-butylperoxycarbonyl) cyclohexane, 2,2-
Bis (t-butylperoxy) octane, n-butyl 4,4-bis (t-butylperoxy) valerate,
2,2-bis (t-butylperoxy) butane, 1,3
-Bis (t-butylperoxy-isopropyl) benzene, 2,5-dimethyl2,5-di (t-butylperoxy) hexane, 2,5-dimethyl-2,5-di (t-butylperoxy) Hexane-3,2,5-dimethyl-
2,5-di (benzoylperoxy) hexane, di-t
-Butyl peroxyisophthalate, 2,2-bis (4,4-di-t-butylperoxycyclohexyl)
Propane, di-t-butylperoxy-α-methylsuccinate, di-t-butylperoxydimethylglutarate, di-t-butylperoxyhexahydroterephthalate, di-t-butylperoxyazelate, 2, 5
Bifunctional radical polymerization initiators such as -dimethyl-2,5-di (t-butylperoxy) -hexane, diethylene glycol bis (t-butylperoxycarbonate) and di-t-butylperoxytrimethyl adipate. These are used singly or in combination and, if necessary, in combination with other radical initiators.

The amount of these radical polymerization initiators used is
The appropriate amount is 0.05 to 5% by weight, preferably 0.1 to 3% by weight, based on the monomers constituting the high-molecular polymer.

In the present invention, polyester, polyurethane, epoxy resin, polyvinyl butyral, rosin, modified rosin, terpene resin, phenol resin, aliphatic or alicyclic hydrocarbon resin, aromatic petroleum resin, etc. Can be used in combination with the binder resin described above.

When two or more resins are mixed and used as a binder resin, as a more preferred form, those having different molecular weights are preferably mixed at an appropriate ratio.

The binder resin contained in the magnetic toner of the present invention has a glass transition temperature of 45 to 80 ° C., preferably 50 to 7 ° C.
Preferably it is 0 ° C.

The method for synthesizing the vinyl binder resin according to the present invention includes a bulk polymerization method, a solution polymerization method, a suspension polymerization method,
A polymerization method such as an emulsion polymerization method can be used.

The composition of the polyester resin is as follows.

The polyester resin used in the present invention comprises:
45 to 55 mol% of all components are alcohol components,
55 to 45 mol% is an acid component.

As the alcohol component, ethylene glycol, propylene glycol, 1,3-butanediol, 1,4-butanediol, 2,3-butanediol, diethylene glycol, triethylene glycol,
1,5-pentanediol, 1,6-hexanediol, neopentyl glycol, 2-ethyl-1,3-hexanediol, hydrogenated bisphenol A, and a bisphenol derivative represented by the formula (a);

[0060]

Embedded image A diol represented by the formula (b);

[0061]

Embedded image And polyhydric alcohols such as glycerin, sorbit, and sorbitan.

The divalent carboxylic acid containing 50 mol% or more of the total acid component includes benzenedicarboxylic acids such as phthalic acid, terephthalic acid, isophthalic acid and phthalic anhydride or anhydrides thereof; succinic acid, adipic acid, sebacine Alkyl dicarboxylic acids such as acids and azelaic acids or anhydrides thereof, and succinic acids or anhydrides further substituted with an alkyl group having 6 to 18 carbon atoms; Saturated dicarboxylic acids or anhydrides thereof and the like, and as the trivalent or higher carboxylic acid, trimellitic acid, pyromellitic acid,
Benzophenone tetracarboxylic acid and its anhydride are exemplified.

The glass transition temperature of the polyester resin is preferably 50 to 75 ° C, more preferably 55 to 65 ° C.

As the fluidizing agent used in the present invention, any material can be used as long as it can be added to the colorant-containing resin particles to increase the fluidity before and after the addition. . For example, there are finely divided silica such as wet-process silica and dry-process silica, and treated silica obtained by subjecting the silica to a surface treatment with a silane coupling agent, a titanium coupling agent, silicon oil, or the like.

Preferred fluidizing agents are fine powders produced by the vapor phase oxidation of silicon halide compounds.
It is what is called dry silica or fumed silica, and is manufactured by a conventionally known technique. For example, it utilizes the thermal decomposition oxidation reaction of silicon tetrachloride gas in an oxyhydrogen flame, and the basic reaction formula is as follows.

SiCl ₄ + 2H ₂ + O ₂ → SiO ₂ + 4HCl In this production process, another metal halide such as aluminum chloride or titanium chloride is used together with a silicon halide to produce a composite fine powder of silica and another metal oxide. It is also possible to obtain bodies, including them. The particle size is 0.0 as an average primary particle size.
It is desirable to be within the range of 01 to 2 μm, and it is particularly preferable to use silica fine powder within the range of 0.002 to 0.2 μm.

The commercially available silica fine powder produced by the vapor phase oxidation of a silicon halide used in the present invention includes, for example, those commercially available under the following trade names.

AEROSIL (Aerosil Japan) 130 200 300 380 TT600 MOX170 MOX80 COK84 Ca-O-SiL (CABOT Co.) M-5 MS-7 MS-75 HS-5 EH-5 Wacker HDK N20 V15 WAC -CHEMIE GMBH) N20E T30 T40 DC Fine Silica (Dow Corning Co.) Fransol (Fransil) On the other hand, the method of producing the silica fine powder used in the present invention by a wet method is known in the art. The method is applicable.
For example, the decomposition of sodium silicate by an acid represented by the following general reaction formula may be mentioned.

Na ₂ O.XSiO ₂ + HCl + H ₂ O →
SiO ₂ .nH ₂ O + NaCl In addition, sodium silicate is decomposed with ammonium salts or alkali salts, an alkaline earth metal silicate is formed from sodium silicate and then decomposed with an acid to form silicic acid, sodium silicate There are a method of converting the solution to silicic acid with an ion exchange resin, and a method of using natural silicic acid or silicate.

For the silica fine powder here, anhydrous silicon dioxide (colloidal silica) and other silicates such as aluminum silicate, sodium silicate, potassium silicate, magnesium silicate and silicic acid can be applied.

Commercially available fine silica powder synthesized by a wet method includes, for example, those commercially available under the following trade names. Carplex Shionogi Niepsil Nippon Silica Tok Seal, Fine Seal Tokuyama Soda Vita Seal Takihito Shilton, Shirunex Mizusawa Chemical Stacyal Kamijima Chemical Himezil Ehime Pharmaceutical Cyloid Fuji Devison Chemical Hi-Sil Hitsil Plate Glass. Co
(Pittsburgh plate glass) Durosil (Durosil) Ultrasil (Ultrasil) Fiillstoff-Gesellschaft M
arquart (Fürstoff Gesellshaft Marquart) Manosil (Manosir) Hardman and Holden (Hardman
And Holden) Hoesch (Hesch) Chemische Fabrik Hosch K
-G (Hemische Fabrik Hesch) Sil-Stone (Sil-Stone) Stoner Rubber Co. (Stoner Rubber) Nalco (Nalco) Nalco Chem. Co. (Narco Chemical) Quoso (Philadelphia Quartz Co.) (Philadelphia Quartz) Imsil Illinois Minerals Co. (Illinois Mineral) Calcium Silikat (Calcium Zilicat) Chemische Fabrik Hoesch. K
-G (Hemische Fabrik Hesch) Calsil (Cardil) Fiillstoff-Gesellschaft M
arquart (Fürstoff-Gezelshaft)
Marquart) Fortafil Imperial Chemical Industr
ies. Ltd. (Imperial Chemical Industries) Microcal (Joseph Crossfields & Sons. L
td. (Joseph Crossfield and Sands) Manosil (Manosil) Hardman and Holden (Hardman
And Holden) Vulkasil Farbenfabriken Bryer, A. et al. −
G. FIG. (Farben Fabry Ken Valley) Tufknit (Tuffnit) Durham Chemicals. Ltd. (Durham Chemicals) Silmos Shiraishi Kogyo Co., Ltd. Star Rex Kamijima Chemical Fricosyl Tawood Manure Of the above silica fine powders, specific surface area by nitrogen adsorption measured by BET method is 30 m ² / g or more (particularly 50 to 4).
(00 m ² / g) gives good results.
Silica fine powder 0.01 to 100 parts by weight of magnetic toner
To 8 parts by weight, preferably 0.1 to 5 parts by weight.

When the magnetic toner according to the present invention is used as a positively charged magnetic toner, the silica fine powder to be added to prevent wear of the toner may be more positively charged than finely charged silica. The use of is preferred without impairing the charging stability.

As a method for obtaining the positively chargeable silica fine powder, the above-mentioned untreated silica fine powder is treated with a silicon oil having an organo group having at least one nitrogen atom in a side chain, And a method of treating with both.

In the present invention, the positively-charged silica refers to a silica having a positive tribocharge with respect to the iron powder carrier when measured by a blow-off method.

As the silicon oil having a nitrogen atom in the side chain used for treating the silica fine powder, a silicon oil having at least a partial structure represented by the following formula can be used.

[0076]

Embedded image (Wherein, R ₁ represents hydrogen, an alkyl group, an aryl group or an alkoxy group, R ₂ represents an alkylene group or a phenylene group, R ₃ and R ₄ represents hydrogen, an alkyl group or an aryl group,, R ₅ Represents a nitrogen-containing heterocyclic group) In the above formula, the alkyl group, the aryl group, the alkylene group, and the phenylene group may have an organo group having a nitrogen atom. It may have such a substituent.

The nitrogen-containing silane coupling agent used in the present invention generally has a structure represented by the following formula.

R _m -Si-Y _n (R represents an alkoxy group or a halogen, Y represents an amino group or an organo group having at least one nitrogen atom, and m and n are integers of 1 to 3. M +
n = 4. Examples of the organo group having at least one nitrogen atom include an amino group having an organic group as a substituent, a nitrogen-containing heterocyclic group, or a group having a nitrogen-containing heterocyclic group. As the nitrogen-containing heterocyclic group, there is an unsaturated heterocyclic group or a saturated heterocyclic group, and known ones can be applied. Examples of the unsaturated heterocyclic group include the following.

[0079]

Embedded image Examples of the saturated heterocyclic group include the following.

[0080]

Embedded image The heterocyclic group used in the present invention is preferably a 5- or 6-membered ring in consideration of stability.

Examples of such treating agents include aminopropyltrimethoxysilane, aminopropyltriethoxysilane, dimethylaminopropyltrimethoxysilane,
Diethylaminopropyltriethoxysilane, dipropylaminopropyltrimethoxysilane, dibutylaminopropyldimethoxysilane, monobutylaminopropyltriethoxysilane, dioctylaminopropyltriethoxysilane, dibutylaminopropyltrimethoxysilane, dibutylaminopropylmonomethoxysilane, dimethyl There are aminophenyltriethoxysilane, trimethoxysilyl-γ-propylphenylamine and trimethoxysilyl-γ-propylbenzylamine, and further, as the nitrogen-containing heterocyclic group, those having the above-mentioned structure can be used. Examples include trimethoxysilyl-γ
-Propylpiperidine, trimethoxysilyl-γ-propylmorpholine, trimethoxysilyl-γ-propylimidazole.

The effect of the treated positively charged silica fine powder is effective when it is 0.01 to 8 parts by weight, particularly preferably 0 to 100 parts by weight, based on 100 parts by weight of the positively charged magnetic toner. When added in an amount of from 1 to 5 parts by weight, it exhibits a positive chargeability having excellent stability. In a preferred embodiment, the addition form is such that 0.1 to 3 parts by weight of the treated silica fine powder adheres to the toner particle surface with respect to 100 parts by weight of the positively charged magnetic toner. good. The untreated silica fine powder described above can be used in the same application amount.

The silica fine powder used in the present invention may be treated with a silane coupling agent or a treating agent such as an organosilicon compound for the purpose of hydrophobicity, if necessary. Treated with the above treating agent. Such treating agents include, for example, hexamethylsilane, trimethylsilane, trimethylchlorosilane, trimethylethoxysilane, dimethyldichlorosilane, methyltrichlorosilane, allyldimethylchlorosilane, allylphenyldichlorosilane, benzyldimethylchlorosilane, bromo Methyldimethylchlorosilane,
α-chloroethyltrichlorosilane, β-chloroethyltrichlorosilane, chloromethyldimethylchlorosilane, triorganosilylmercaptan, trimethylsilylmercaptan, triorganosialylate, vinyldimethylacetoxysilane, dimethylethoxysilane,
Dimethyldimethoxysilane, diphenyldiethoxysilane, hexamethyldisiloxane, 1,3-divinyltetramethyldisiloxane, 1,3-diphenyltetramethyldisiloxane, and 2 to 12 siloxane units per molecule, Are dimethylpolysiloxanes each containing one hydroxyl group bonded to Si. These are used alone or in a mixture of two or more.

The magnetic toner of the present invention may also serve as a colorant, but contains a magnetic material. Examples of the magnetic material contained in the magnetic toner of the present invention include iron oxides such as magnetite, γ-iron oxide ferrite, and iron-rich ferrite; metals such as iron, cobalt, and nickel, or aluminum and cobalt; Copper, lead, magnesium, tin, zinc, antimony, beryllium, bismuth,
Cadmium, calcium, manganese, selenium, titanium,
Alloys with metals such as tungsten and vanadium, and mixtures thereof, and the like can be given.

These ferromagnetic materials have an average particle size of 0.1 to 1
μm, and preferably about 0.1 to 0.5 μm.
The amount is from 60 to 110 parts by weight, preferably from 65 to 100 parts by weight, per 100 parts by weight of the resin component.

In the magnetic toner of the present invention, it is preferable to use a charge control agent in the toner particles by mixing (internal addition) or mixing with the toner particles (external addition). Depending on the charge control agent,
It is possible to control the amount of charge optimally according to the developing system. In particular, in the present invention, the balance between the binder resin and the charge can be further stabilized. Examples of the positive charge control agent include denatured products such as nigrosine and fatty acid metal salts; quaternary ammonium salts such as tributylbenzylammonium-1-hydroxy-4-naphthosulfonate and tetrabutylammonium tetrafluoroborate; dibutyltin oxide and dioctyltin Diorganotin oxides such as oxide and dicyclohexyltin oxide; diorganotin borates such as dibutyltin borate, dioctyltin borate and dicyclohexyltin borate can be used alone or in combination of two or more. Among these, charge control agents such as nigrosine and quaternary ammonium salts are particularly preferably used.

General formula

[0088]

Embedded image [Wherein, R ₁ represents H or CH ₃ , and R ₂ and R ₃
Is a substituted or unsubstituted alkyl group (preferably a C ₁ to
C ₄₎ shows the. Or a copolymer with a polymerizable monomer such as styrene, an acrylate or a methacrylate as described above can be used as a positive charge control agent. The charge control agent also has an action as (all or part of) the binder resin.

The above-mentioned charge control agent (having no function as a binder resin) is preferably used in the form of fine particles. In this case, the number average particle size of the charge control agent is
Specifically, it is preferably 4 μm or less (more preferably 3 μm or less).

When the charge control agent is internally added to the toner, it is preferable to use 0.1 to 20 parts by weight (more preferably 0.2 to 10 parts by weight) based on 100 parts by weight of the binder resin.

In the magnetic toner according to the present invention, various additives may be added internally or externally as necessary. As the colorant, conventionally known dyes and pigments can be used, and usually 0.5 to 20 parts by weight per 100 parts by weight of the binder resin may be used.

The metal oxide powder used in the present invention includes oxides such as magnesium, zinc, cerium, aluminum, cobalt, iron, zirconium, manganese, chromium and strontium, and calcium titanate, magnesium titanate and strontium titanate. And composite metal oxides such as barium titanate. Above all,
Zinc oxide, cerium oxide, aluminum oxide, cobalt oxide, manganese dioxide, strontium titanate, and magnesium titanate are preferable because the effects of the present invention can be further exhibited. In particular, strontium titanate powder is preferable.

The metal oxide powder used in the present invention is produced by, for example, a sintering method, mechanically pulverized, then classified by air classification, and has a desired particle size and particle size distribution.

The metal oxide powder according to the present invention is used for toner 1
It is preferably used in an amount of 0.01 to 20 parts by weight, preferably 0.1 to 10 parts by weight, based on 00 parts by weight.

To prepare the toner for developing an electrostatic image of the present invention, a binder resin, a magnetic substance, and, if necessary, a colorant, a charge control agent or other additives are mixed with a mixer such as a Henschel mixer or a ball mill. Mix well, heat, knead and knead using a hot kneader such as a heating roll, kneader, extruder to make the resins compatible with each other, cool and solidify the melt-kneaded product, pulverize the solidified product, and pulverize. Can be obtained to obtain the toner of the present invention.

Further, the fluidizing agent, the metal oxide powder, the toner and the toner are sufficiently mixed by a mixer such as a Henschel mixer to obtain a developer for developing an electrostatic image of the present invention having an additive on the surface of toner particles. .

<Measurement of Particle Size Distribution>
Although it can be measured by various methods, in the present invention, the measurement was performed using a Coulter counter multisizer.

That is, as the measuring device, a Coulter counter Multisizer II (manufactured by Coulter) was used, and an interface (manufactured by Nikkaki) for outputting the number distribution and volume distribution and a CX-1 personal computer (manufactured by Canon) were connected. Then, a 1% NaCl aqueous solution is prepared using a special grade or primary grade sodium chloride as an electrolytic solution. As a measurement method, 0.1 to 5 ml of a surfactant, preferably an alkylbenzene sulfonate, is added as a dispersing agent to 100 to 150 ml of the electrolytic aqueous solution, and the measurement sample is added to 2 to 100 ml.
Add ~ 20 mg. The electrolytic solution in which the sample is suspended is subjected to dispersion treatment for about 1 to 3 minutes with an ultrasonic disperser, and a multi-sizer type II of the Coulter counter uses a 100 μm aperture when measuring the toner particle size as an aperture. 13μ when measuring the particle size of inorganic fine powder
Measure using an m aperture. The volume and the number of the toner and the metal oxide powder were measured, and the volume distribution and the number distribution were calculated. Then, the weight-based weight average diameter determined from the volume distribution according to the present invention is determined from the volume distribution.

<Measurement of Glass Transition Temperature Tg> In the present invention, a differential thermal analysis measuring device (DSC measuring device), a DSC
-7 (manufactured by PerkinElmer).

The measurement sample is 5 to 20 mg, preferably 10
Weigh the mg precisely.

This was put in an aluminum pan, and an empty aluminum pan was used as a reference.
The measurement is performed at a temperature rising rate of 10 ° C./min and at normal temperature and normal humidity between 0 ° C.

In this heating process, an endothermic peak of a main peak in a temperature range of 40 to 100 ° C. is obtained.

The intersection of the line of the midpoint of the baseline before and after the endothermic peak appears and the differential heat curve is defined as the glass transition temperature Tg in the present invention.

[0104]

The basic configuration and features of the present invention have been described above, and the present invention will be specifically described below with reference to examples. However, this does not limit the invention in any way.

An example of a specific apparatus that can be used for performing the image forming step in the present invention will be described with reference to FIG.

Reference numeral 1 denotes a rotating drum type photoreceptor. The photoreceptor 1 comprises a conductive base layer 1b made of aluminum or the like and a photoconductive layer 1a formed on the outer surface thereof as a basic constituent layer. The surface portion of the conductive layer 1a is made of a polycarbonate resin containing 8% by weight of a charge transporting substance and a fluorine resin fine powder. Peripheral speed 200m clockwise on the drawing
It is driven to rotate at m / sec.

Reference numeral 2 denotes a charging roller, and a central core 2b
And a conductive elastic layer whose outer periphery is formed of epichlorohydrin rubber containing carbon black.

The charging roller 2 is pressed against the surface of the photosensitive member 1 with a pressing pressure of a linear pressure of 40 g / cm, and is driven to rotate as the photosensitive member 1 rotates. Further, a felt pad 12 is brought into contact with the charging roller 2 as a cleaning member.

Reference numeral 3 denotes a charging bias power source for applying a voltage to the charging roller 2, and a DC-14
By applying a bias of 00V, the surface potential of the photoconductor 1 is charged to a polarity and potential of about -700V.

Next, an electrostatic latent image is formed by the image exposure 4, and is visualized as a toner image sequentially by the developing means 5.

Reference numeral 6 denotes a transfer roller, which is a central cored bar 6b.
And a conductive elastic layer 6a whose outer periphery is formed of an ethylene-propylene-butadiene copolymer containing carbon black
And the basic configuration. The transfer roller 6
The photoreceptor 1 is pressed against the surface of the photoreceptor 1 with a predetermined linear pressure, and rotates at a constant speed or a predetermined peripheral speed difference with the peripheral speed of the photoreceptor 1. Further, the transfer roller 6 is in contact with a felt pad 13 as a cleaning member.

A4 size paper is used as the transfer material 8,
This is transported between the photoconductor 1 and the transfer roller 6, and at the same time, a bias of −5000 V DC is applied to the transfer roller 6 from the transfer bias power supply 7 so that the toner image on the photoconductor 1 is transferred to the surface of the transfer material 8. Is transferred to

Next, the transfer material 8 is conveyed to a fixing unit 11 having a heating roller 11a containing a halogen heater therein and an elastic pressure roller 11b pressed against the roller 11a with a pressing force. And 11b, the toner image is fixed on the transfer material 8 and discharged as an image formed product.

On the surface of the photoreceptor 1 after transfer of the toner image, elastic contaminants such as a residual developer after transfer are elastically cleaned using a polyurethane rubber as a basic material pressed against the photoreceptor 1 at a linear pressure of 25 g / cm in a counter direction. The surface is cleaned by a cleaning device 9 equipped with a blade, and is further subjected to static elimination by a static elimination exposure device 10 to repeatedly form an image.

[Production Example of Strontium Titanate] 600 g of strontium carbonate and 320 g of titanium oxide were wet-mixed in a ball mill for 8 hours and then filtered and dried. This mixture was molded at a pressure of 5 kg / cm ² and calcined at a temperature of 1100 ° C. for 8 hours.

Thereafter, the mixture was mechanically pulverized to have a weight average diameter of 1.8 μm.
m, number average diameter 0.7 μm, particle size distribution [(m−D ₄ ) /
(M-D ₁ )] to obtain strontium titanate fine powder of 2.6. This is designated as strontium titanate A. The coarse powder and the fine powder were simultaneously removed by an elbow jet classifier utilizing the Coanda effect to obtain a weight average diameter of 1.4.
μm, number average diameter 1.0 μm, particle size distribution [(m-D ₄ )
/ (M-D ₁ )] 1.4, thereby obtaining strontium titanate [1].

Similarly, strontium titanates [2] and [4] having various particle size distributions were obtained.

The calcined strontium titanate before mechanical pulverization was classified by an elbow jet classifier to obtain strontium titanate [3]. The results are shown in Table 1.

[0119]

[Table 1] [Production Example of Developer] Styrene-acrylic copolymer (83:17) 80 parts Low molecular weight polypropylene 4 parts Styrene-butadiene copolymer (84:16) 20 parts Magnetic iron oxide 90 parts Nigrosine 2 parts After pre-mixing with a mixer, 150
Melt kneading was performed at 2 ° C. by a twin screw kneading extruder. The kneaded product was allowed to cool, coarsely pulverized, and finely pulverized. Further, a black magnetic toner having the following average particle diameter was obtained using an air classifier.

(T−D ₄ ) = 9.0 μm (t−D ₁ ) = 7.0 μm (t−D ₄ ) / (t−D ₁ ) = 1.3 Further, the Tg of the toner is 60.0 ° C. It is.

To 100 parts of this magnetic toner, 0.6 part of hydrophobic positively-charged silica (BET value; 130 m ^{2 /} g),
3.0 parts of strontium titanate [1] is externally added using a Henschel mixer, and [(m-D ₄ ) / (m-D ₁ )] / [(t-D ₄ ) /
(T−D ₁ )] = 1.08 was obtained.

Similarly, instead of strontium titanate [1], strontium titanate [2],
[3] and [4] were externally added to the magnetic toner to obtain developers [2], [3] and [4].

Similarly, a developer [5] was obtained by externally adding only silica without adding strontium titanate.

Example 1 In the image forming apparatus shown in FIG. 2, the pressing pressure of the transfer roller against the photosensitive member was 3 and 20 g / c.
m (linear pressure) Peripheral speed difference with respect to photoreceptor: 0.5 / 1.5 / 3.0 /
5.0 / -0.5 / -1.5 / -3.0 / -5.0% Developing bias condition Vpp: 1300 V (AC) Vf: 1800 Hz Vdc: -210 V (DC) Photoconductor and developer carrier Distance between: 300 μm, 20,000 sheets of image endurance test was performed using developer 1 and A4 size (transversely fed) paper as a transfer material.

As a result, filming of a practically allowable level occurred at a peripheral speed difference of ± 0.5%, but no filming, toner fusion, and scratches on the photoreceptor surface occurred at other times. Good durability and cleaning properties were obtained.

Further, the charging property and the cleaning property of the transfer roller surface by the cleaning pad were also good.

[Example 2] In place of developer 1, developer 2
An experiment similar to that of Example 1 was performed, except that was used.

As a result, similarly to the first embodiment, the peripheral speed difference ±
At 0.5%, filming of a practically acceptable level occurs, but otherwise, no filming, toner fusion, and scratches on the photoreceptor surface occur, and good durability and cleaning properties are obtained. Was.

In addition, the cleaning properties of the charging roller and the surface of the transfer roller with a cleaning pad were also good.

Example 3 A photoconductor made of an organic semiconductor material containing no fluorinated resin fine particles in the surface layer was used.
The pressing pressure of the transfer roller against the photoconductor is 20 g / cm (linear pressure), and the peripheral speed difference between the photoconductor and the transfer roller is ± 1.5.
%, Except that developers 1 and 2 were used.
The same experiment was performed.

As a result, although the surface of the photosensitive member was slightly scratched to the extent that it could be visually confirmed, filming and toner fusion did not occur, and relatively good durability and cleaning characteristics were obtained. Was.

Further, the cleaning properties of the charging roller and the surface of the transfer roller with a cleaning pad were also good.

[Comparative Example 1] Developer 3 in place of Developer 1
And the pressing pressure of the transfer roller against the photoconductor is 20 g / c.
The same experiment as in Example 1 was performed except that m (linear pressure) was used.

As a result, filming and toner fusion occurred at all the peripheral speed differences. The occurrence level of filming and toner fusion improves with the increase in peripheral speed difference,
Conversely, scratches on the photoreceptor surface layer increased. Further, as the number of durable sheets increases, the image density decreases, and it is not practical.

[Comparative Example 2] Developer 4 instead of Developer 1
The pressing pressure of the transfer roller against the photoreceptor is adjusted to 20 g /
The same experiment as in Example 1 was performed except that the pressure was set to cm (linear pressure).

As a result, the occurrence levels of filming and toner fusing were the same as in Example 1, and were excellent. However, scratches on the surface layer of the photoreceptor, poor cleaning, and contamination of the charging roller occurred. As a result, it was not practical.

[Comparative Example 3] The pressing force of the transfer roller against the photosensitive member was set to 1 g / cm (linear pressure), the peripheral speed difference between the photosensitive member and the transfer roller was set to ± 1.5%, , 3 and 4, except that the same experiment as in Example 1 was performed.

As a result, filming and toner fusion occurred under all conditions, and transfer failure occurred.

[Comparative Example 4] The transfer roller was pressed against the photosensitive member at a pressure of 20 g / cm (linear pressure), and the peripheral speed difference between the photosensitive member and the transfer roller was 0%, that is, the roller was rotated at the same peripheral speed. The same experiment as in Example 1 was performed except that agents 1 and 2 were used.

As a result, in the case where there was no difference in peripheral speed, filming and toner fusion at a considerably bad level occurred.

Comparative Example 5 The pressing pressure of the transfer roller against the photosensitive member was set to 20 g / cm (linear pressure), the peripheral speed difference between the photosensitive member and the transfer roller was set to ± 6.0%. An experiment similar to that of Example 1 was performed, except that was used.

As a result, no filming or toner fusion occurred, but scratches occurred on the surface layer of the photoreceptor.

Comparative Example 6 The same procedure as in Example 1 was performed except that the pressing pressure of the transfer roller against the photosensitive member was set to 20 g / cm (linear pressure), and developer 5 was used instead of developer 1. An experiment was performed.

As a result, in the case of the developer containing no metal oxide powder as an abrasive, poor levels of filming and toner fusion occurred regardless of the peripheral speed difference.

Comparative Example 7 A photoconductor made of an organic semiconductor material containing no fluorine-containing resin fine particles in the surface layer was used.
The pressing pressure of the transfer roller against the photoconductor is 20 g / cm (linear pressure), and the peripheral speed difference between the photoconductor and the transfer roller is ± 1.5.
%, Except that developers 3 and 4 were used.
The same experiment was performed.

As a result, no filming or toner fusion occurred, but sharp scratches occurred on the surface of the photoreceptor.

[Comparative Example 8] A photoconductor made of an organic semiconductor material containing no fluorine-containing resin fine particles in the surface layer was used.
It is assumed that the transfer roller is pressed against the photoconductor at a pressure of 20 g / cm (linear pressure), the peripheral speed difference between the photoconductor and the transfer roller is 0%, that is, the developer is rotated at the same peripheral speed, and the developers 1 and 2 are used. Except for this, the same experiment as in Example 1 was performed.

As a result, considerably poor levels of filming and toner fusion occurred, and sharp scratches were observed on the surface of the photoreceptor which could be visually confirmed.

The results of the above Examples and Comparative Examples are shown in Tables 2 and 3.

[0150]

[Table 2]

[0151]

[Table 3]

[0152]

According to the present invention, it is possible to prevent the adhesion of paper powder and various products to the surface of the photoreceptor and the fixation of developer components such as filming and toner fusion, and always obtain a stable copy or image. be able to.

In the charging step, by preventing the toner component from sticking to the surface of the charging member, the contact between the charging member and the photosensitive member can be sufficiently maintained, and the charging failure such as uneven charging can be prevented. Can be.

In the transfer step, by preventing the toner component from sticking to the surface of the transfer member, it is possible to prevent image defects from occurring and to provide a stable copy image.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram of an image forming apparatus using a contact charging / contact transfer method.

FIG. 2 is another schematic configuration diagram of an image forming apparatus using a contact charging / contact transfer method.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 electrostatic image carrier (photoconductor) 2 charging roller 3 charging bias application power supply 4 image exposure 5 developing means 6 transfer roller 7 transfer bias application power supply 8 transfer material 9 cleaning means 10 static elimination exposure 11 fixing means 12 charging roller cleaning means 13 Transfer roller cleaning means

──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Kazuyoshi Hagiwara 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc. (72) Inventor Toshiaki Nakahara 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon (56) References JP-A-63-247780 (JP, A) JP-A-56-144474 (JP, A) JP-A-63-115177 (JP, A) JP-A-62-119550 (JP, A A) JP-A-2-93576 (JP, A) JP-A-4-44051 (JP, A) (58) Fields investigated (Int. Cl. ⁶ , DB name) G03G 15/16 103 G03G 9/08 G03G 21/00 312

Claims (2)

(57) [Claims] 1. A photoconductor having an organic semiconductor material is contacted with a charging member to which a voltage is applied to charge the photoconductor, and the photoconductor is exposed to form an electrostatic latent image. In the electrostatic latent image, a fluidizing agent, a weight average particle diameter (m-D ₄ ) is 0.6 to 5 μm, a number average particle diameter (m-D ₁ ) is 0.5 to 4 μm, and (m _{-D 4) / (m-D} 1) the ratio of developed to form a magnetic toner image by a magnetic developer containing a metal oxide powder and a magnetic toner is 1.0 to 2.4, from the photoreceptor Image forming characterized in that the toner image is electrostatically transferred to the transfer material while pressing the transfer material with a linear member at a linear pressure of 3 g / cm or more by a transfer member to which a voltage is applied, and having a peripheral speed difference with respect to the photosensitive member. Law. 2. The image forming method according to claim 1, wherein the photoreceptor has an organic semiconductor material layer containing fine particles of a fluorine-containing resin on a surface layer.