JPH06102699A - Picture forming method - Google Patents

Abstract

PURPOSE:To ford a picture excellent in transparency by using this device capable of being miniaturized. CONSTITUTION:A nonmagnetic one-component developer layer is formed on a developer carrier arranged at a position in contact with an electrostatic latent image carrier by using a press member in contact with the developer carrier. A developer is supplied to the image carrier in which an electrostatic latent image is formed from the developer carrier to develop the electrostatic latent image. The 10% displacement tensile strength is controlled to >=0.7kgf/mm<2>.

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,
In particular, the present invention relates to an image forming method for visualizing an electrostatic latent image with a developer of two or more colors.

[0002]

2. Description of the Related Art In order to visualize an electrostatic latent image, a two-component developing system has been widely used, in which a developer containing a toner and a carrier is used for development. This method has an advantage that a high-quality image can be easily obtained because a material having a wide range of characteristics can be used depending on the combination of the toner and the carrier, because the method has relatively little environmental dependence. .

On the other hand, in recent years, a full-color image forming method using an electrophotographic system has appeared and is being actively developed. This system mainly reproduces colors with three color developers of cyan, magenta, and yellow, and the developer image of the above three colors on the material to be transferred, or four colors of black obtained by adding black to the above three colors. A color image is obtained by transferring the developer image and heating and melting and fixing the image with a flash, a heat roller, an oven, or the like. However, since this system uses developers of three or four colors, three or four sets of developing devices are also required, and when the two-component developing system is used, the weight and volume of the image forming unit are very large. It becomes a big thing. Also, in order to reproduce a full-color image, it is necessary to finely adjust the density of three or four colors,
The toner concentration in the developer must be strictly controlled.

Therefore, a non-magnetic one-component developing system is attracting attention, in which toner is developed by friction and / or contact charging between a metal or synthetic resin pressure contact member and a developer carrying member. According to this method, since no carrier is required, it is possible to reduce the weight and size of the image forming unit, and the maintenance is easy. Further, since the distance between the electrostatic latent image carrier and the developer carrier, which is the counter electrode, is shorter than that in the two-component developing system, high-definition development can be performed at low voltage.

[0005]

As described above, the one-component developing system has many excellent advantages as compared with the two-component developing system. However, forming a full-color image by the one-component developing method has the following drawbacks.

That is, in order to sufficiently perform fixing in a portion where a plurality of types of developers are overlapped and to improve color reproduction, the plurality of types of developers must be sufficiently melted. The developer used for a single color is usually composed of a binder resin having a softening point of about 130 to 180 ° C., but the binder resin used for the developer for full-color images has a softening point lower than the above temperature range. Have. However, in the one-component developing method, the developer is triboelectrically charged by the pressure contact member and the developer carrier, and therefore, when a conventional full-color image developer having a low softening point is used, the pressure contact member and the developer carrier are It is easy to stick and it is difficult to stably tribocharge the developer. As a result, the developer is uncharged and oppositely charged,
These uncharged and oppositely charged developers cause problems such as fogging of non-image areas, scattering of the developer in the machine, and missing images due to defective conveyance of the developer. Therefore, an object of the present invention is to provide an image forming method which solves the above problems and makes it possible to obtain a full-color image.

[0007]

SUMMARY OF THE INVENTION In order to solve the above problems, the present invention is directed to a developer carrying member arranged at a position in contact with an image carrying member on which an electrostatic latent image is formed. A step of forming a non-magnetic one-component developer layer using a pressure contact member in contact with the carrier, and supplying the developer from the developer carrier to the electrostatic latent image carrier to develop the electrostatic latent image And a developer of 0.7 kgf / mm ² More than 10
Provided is an image forming method having a% displacement tensile strength.

In order to increase the tensile strength of the developer, it is necessary to increase the mechanical strength of the binder resin by increasing the degree of polymerization of the binder resin which is a main constituent of the developer or increasing the molecular weight. Good. For example, the degree of polymerization can be increased by reducing the amount of the polymerization initiator added or increasing the polymerization reaction time. Further, the molecular weight can be increased by changing the resin composition to raise the glass transition temperature or by adding a crosslinking agent to partially form crosslinking points in the polymer. On the other hand, the mechanical strength is also improved by adding a filler to the developer particles or subjecting the developer particles to a spheroidizing treatment. When a developer is produced by the agglomeration method, polymer particles with a small particle size are agglomerated to a desired particle size, and then heat treatment is used to fuse the contact parts of each particle to form a strong agglomerate. is doing. If this heat treatment is insufficient, the particles tend to collapse in aggregation, but the strength can be improved by spheroidizing to some extent. Further, the developer particles obtained by the pulverization method are angular, and since the angular portions are easily crushed, rounding the corners improves the strength.

Examples of the filler dispersed in the developer particles include organic and inorganic pigments and magnetic particles such as iron oxide, chromium oxide, nickel ferrite, iron-manganese-cobalt alloy and the like. The mechanical strength can be improved by increasing the addition amount of the pigment and adding 20% by weight or less of the magnetic substance.

The resin, which is the main component of the non-magnetic one-component developer, has a glass transition point of 50 ° C. or higher, a softening point measured by a flow tester (nozzle diameter 1 mm, extrusion pressure 1
0 mmf / cm ² , The starting temperature 80 ℃), but 80 ℃ or more 1
It is 50 ° C or lower. If the glass transition point is lower than 50 ° C, the storage stability tends to decrease. When the softening point is 150 ° C. or higher, it becomes difficult to sufficiently perform heat fixing. Furthermore, 90% or more of the particle size distribution of the developer is preferably 3 μm to 15 μm. If the particle size distribution is broader than this, the charge amount distribution will also be broad, and it will be difficult to obtain high-definition images.

The non-magnetic one-component developer used in the image forming method of the present invention can be produced by a wet / aggregation method, a suspension polymerization method, an emulsion polymerization method, a dispersion polymerization method, or a pulverization method.

When the developer applied to the present invention is manufactured by a wet method, the polymerizable monomer used is styrene, o-methylstyrene, m-methylstyrene, p-methylstyrene, p-methoxystyrene, p-. Phenylstyrene, p
-Chlorostyrene, 3,4-dichlorostyrene, p-ethylstyrene, 2,4-dimethylstyrene, pn-butylstyrene, p-tert-butylstyrene, pn
-Hexyl styrene, pn-octyl styrene, p-
n-nonylstyrene, pn-decylstyrene, pn
-Styrene such as dodecyl styrene and its derivatives; glycols such as ethylene glycol and propylene glycol; unsaturated fatty acids such as maleic anhydride and phthalic anhydride; ethylenically unsaturated monoolefins such as ethylene, propylene, butylene and isobutylene; Vinyl halides such as vinyl chloride, vinylidene chloride, vinyl bromide and vinyl fluoride; vinyl esters such as vinyl acetate, vinyl propionate and vinyl benzoate; methyl methacrylate,
Ethyl methacrylate, propyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, n-octyl methacrylate, dodecyl methacrylate, 2-ethylhexyl methacrylate, stearyl methacrylate, phenyl methacrylate, dimethylaminomethyl methacrylate,
Α-Methylene aliphatic monocarboxylic acid esters such as diethylaminoethyl methacrylate; methyl acrylate, ethyl acrylate, propyl acrylate, n-acrylic acid
Acrylic esters such as butyl, isobutyl acrylate, n-octyl acrylate, dodecyl acrylate, 2-ethylhexyl acrylate, stearyl acrylate, phenyl acrylate, 2-chloroethyl acrylate; vinyl methyl ether, vinyl ethyl ether, Vinyl ethers such as vinyl isobutyl ether; vinyl ketones such as vinyl methyl ketone, vinyl hexyl ketone and methyl isopropenyl ketone; n-vinyl pyrrole, n-
Examples thereof include n-vinyl compounds such as vinylcarbazole, n-vinylindole, and n-vinylpyrrolidone; vinylnaphthalenes; vinylic monomers such as acrylonitrile, methacrylonitrile, acrylamide, and other acrylic acid or methacrylic acid derivatives.

As the polymerization initiator, for example, benzoyl peroxide, di-t-butyl peroxide, lauroyl peroxide, t-butyl hydroperoxide, cumene hydroperoxide, potassium persulfate, ammonium persulfate, acetyl persulfate, tetramethylthylium zirconium can be used. Sulfide, azobisisobutyronitrile, azobiscyclohexanenitrile, phenylazotriphenylmethane, triethylaluminum, ethylaluminum dichloride, diethylaluminium chloride, tetraethyllead,
Use diethyl zinc, diethyl cadmium, tetraethyl tin, titanium tetrachloride, aluminum chloride, aluminum bromide, stannic chloride, boron trifluoride diethyl etherate, boron trifluoride, zinc chloride, phosphorus pentafluoride, etc. You can The amount of the polymerization initiator used is generally about 0.5 to 5.0% by weight of the monomer.

As the cross-linking agent, 2,4-dichlorobenzoyl peroxide, n-butyl-4,4'-di (t-butylperoxy) valerate dicumyl peroxide, t
-Peroxides such as butylperoxycumene, and quinonedioxime-based compounds such as p-quinonedioxime.p, p'-dibenzoyl.quinonedioxime and ethylene glycol dimethacrylate. Methacrylic acid such as methyl methacrylate, acrylic such as diallyl phthalate and triallyl cyanurate,
Maleimides such as maleimide / N, N'-m-phenylene bismaleimide, maleic anhydride, divinylbenzene, vinyltoluene and the like can be used.

Wax or the like may be used for the purpose of improving the releasability of the developer from the heat roller during fixing by the heat roller. Examples of waxes that can be used include paraffins, aliphatic hydrocarbons such as polyolefins, higher fatty acids, aliphatic alcohols, fatty acid amides, fatty acid esters, and metal soaps.

As the colorant, for pigments, inorganic pigments (natural, chromate, ferrocyanine compound, oxide, sulfide, silicate, metal powder, etc.), organic pigments (natural dye lake,
Nitroso type, azo type, phthalocyanine type, condensed polycyclic type,
Basic dye lakes, mordant dyes, vat dyes, etc.), and examples of the dyes include water-soluble dyes and oil-soluble dyes. Examples of the inorganic pigment include natural pigments such as loess, yellow lead, zinc yellow, barium yellow, chrome orange,
Chromates such as molybdenum red and chrome green, ferrocyan compounds such as navy blue, titanium oxide, titanium yellow, titanium white, red iron oxide, yellow iron oxide, zinc ferrite, zinc white, cobalt blue, chromium oxide, and spinel green sulfide. Substances, sulfates such as barium sulfate, calcium silicate, silicates such as ultramarine, metal powders such as bronze and aluminum, carbon blacks and the like. Examples of organic pigments include natural lakes such as Madare Lake, nitroso pigments such as Naphthol Green and Naphthol Orange, Benzidine Yellow G, Hansa Yellow G, Hansa Yellow G10, Balkan Orange, Lake Red R, and the like.
Lake Red C, Lake Red D, Watching Red, Brilliant Carmine 6B, Pyrralozone Orange,
Soluble azo (azo lake) type such as Bordeaux 10G (Bon Maroon), insoluble azo type such as pyrarozone red, para red, toluidine red, ITR red, lake red 4R, toluidine maroon, brilliant fast scarlet, lake bordeaux 5B, condensed azo type Azo pigments such as phthalocyanine blue, phthalocyanine green, brominated phthalocyanine green, phthalocyanine pigments such as fast sky blue, anthraquinone pigments such as slene blue, perylene pigments such as perylene maroon, perinone pigments such as perinone orange, quinacridone,
Condensed polycyclic pigments of quinacridone type such as dimethylquinacridone, dioxazine type such as dioxazine violet, isoindolinone type, quinophthalone type, rhodamine 6B
Lake, rhodamine lake B, basic dye lakes such as malachite green, mordant dye pigments such as alizarin lake, vat dye pigments such as indanthrene blue, indigo blue and anthanthrone orange, fluorescent pigments, azine pigments (diamond) Pigments such as black) and green gold can be used. Examples of the dye include basic dyes such as rhodamine B, acid dyes such as orange II, and fluorescent dyes. Examples of the oil-soluble dyes include monoazo dyes such as Fast Orange R, oil red, and oil yellow, anthraquinone. Examples thereof include anthraquinone dyes such as blue and anthraquinone violet, azine dyes such as nigrosine and indurine, and basic, acidic and metal complex compound dyes.

The resin used when the developer is manufactured by the mechanical pulverization method is, for example, polystyrene, styrene-based copolymers such as polystyrene-butadiene copolymer, styrene-acrylic copolymer, polyethylene, Ethylene copolymers such as polyethylene-vinyl acetate copolymer, polyethylene-vinyl alcohol copolymer, phenol resin, polyamide resin, polyester resin, maleic acid resin, polymethylmethacrylate, polyacrylic acid, polyvinyl butyral , Polycarbonate resins, epoxy resins, aliphatic or alicyclic hydrocarbon resins, so-called petroleum resins such as aromatic hydrocarbons, and mixtures thereof. As the colorant, wax, etc., the same materials as those used in the wet manufacturing can be used.

Further, a part or all of the surface of the obtained developer particles can be covered with inorganic or polymer fine particles for the purpose of improving fluidity, improving storage stability by encapsulation, adjusting charge amount and the like. . As the inorganic fine particles, submicron-sized colloidal silica, inorganic oxides such as titanium oxide, cerium oxide, and aluminum oxide, pigment particles such as carbon black, etc. are used alone or in combination depending on the charging property. be able to. As the polymer fine particles, polymethylmethacrylate, polystyrene, polycarbonate, polyethylene, vinyl acetate, vinyl chloride, polyvinyl butyral, nylon, polysulfone, polyethylene oxide and the like can be used. In addition, these fine particles may be subjected to a hydrophobic treatment for controlling moisture resistance, and a surface treatment with nigrosine, a metal azo dye or the like for controlling charging property.

The wet / aggregation method is shown below as an example of the method for producing the developer used in the image forming method of the present invention. The developer is produced by a generally known suspension polymerization method, emulsion polymerization method or the like. May be. Further, it is also possible to obtain a developer having a desired particle diameter by dry kneading, pulverizing and classifying constituents such as resin and pigment.

A required amount of a colorant, an optional charge control agent and the like are added to and mixed with an emulsion of a polymer having an acidic polar group or a basic polar group obtained by emulsion polymerization of a polymerizable monomer. Evenly disperse 10 to 40%, 0.5
Continue stirring for ~ 3 hours, preferably 1-2 hours. Then, add the remaining mixture and disperse evenly,
When the mixture is stirred for 0.5 to 3 hours, preferably 0.5 to 1.5 hours, the primary particles of the polymer having a polar group and the colorant particles gradually aggregate to form an average particle diameter of 0.5 to 3 μm. Have 2
Secondary particles grow. When such a dispersion is further stirred as it is for 0.5 to 3 hours, preferably 1 to 2 hours, the secondary particles further aggregate and grow into associated particles having an average particle diameter of 3 to 15 μm. When the dispersion liquid thus produced is continuously stirred for 1 to 6 hours, preferably 2 to 4 hours, at a temperature 20 ° C. higher than the glass transition point of the polymer having a polar group to the glass transition point, each of the associated particles Contact portions of the film are fused to form a strong aggregate. This is washed and filtered to remove surfactants etc. from the developer surface,
After drying, a developer is obtained by externally adding a fluidity imparting agent.

[0021]

The image forming method of the present invention has a 10% displacement tensile strength of 0.7 kgf / mm ² The above developer is used. The 10% displacement tensile strength can be determined by a micro compression tester (manufactured by Shimadzu Corporation). In this device, one fine particle is fixed between an upper pressing indenter (a flat indenter with a diameter of 50 μm) and a lower pressing plate, and a pressing force is applied at a constant increasing rate by an electromagnetic force. It is something to measure. The 10% displacement tensile strength can be obtained from the load when the displacement of 10% of the grain size occurs, by the following equation (1). St = 2.8P / πd ² (1)

In the formula (1), St is the tensile strength (kgf /
mm ² ) And P represent weight (kg) and d represents particle size (mm). In addition, the measurement is a test load of 1 kgf and a load speed of 18 m.
The measurement is performed under the conditions of df / sec and 10 measurement samples.

As described above, since the developer used in the method of the present invention has a large strength against a load, it is less likely to be crushed by the stress caused by the friction with the frictional charging member such as the charging blade. Therefore, the developers are kept in contact with each other, and the developer is kept in contact with the pressing member and the developer carrier at a point, so that the strong van der Waals force does not cause an adhesive force.

The adhesive force and cohesive force of a solid are mainly intermolecular force,
Although caused by electrostatic force, the intermolecular force is larger as the facing area is larger, and when the developer is crushed by stress, the developer particles and the developer and the developer carrier,
The contact area with the pressing member increases and the adhesive force increases, so that the developer adheres to the developer carrier or the pressing member.

On the other hand, since the developer used in the image forming method of the present invention has a large tensile strength and is hard to be crushed, it does not stick to the pressure-contact member, the developer carrying member, or the like, nor aggregate. Therefore, according to the present invention, even when a full-color developer having a low softening point is used, variations in charge due to sticking of the developer and developer conveyance failure do not occur,
The developer charge amount and developer transportability are stable for a long period of time. As a result, a high-definition full-color image can be obtained by the image forming method of the present invention.

[0026]

Embodiments of the present invention will now be described in detail with reference to the drawings.

FIG. 1 is a schematic configuration diagram showing an example of a developing device used in the image forming method of the present invention. The developing device 10 includes a developer container 13 containing a non-magnetic one-component developer 14, and a developer carrier 11 arranged in the developer container 13. The developer carrier 11 is electrostatically charged. It is in contact with the latent image carrier 15. The developer carrying member 11 has a charging blade 12 made of an elastic material in an amount of 200 g / cm to 100
It is pressed with a linear pressure of 0 g / cm. Inside the container 13, a developer supply roller 17 is installed so as to be in contact with the developer carrier 11, and a stirrer 18 for stirring the developer 14 is provided.

In the developing device 10 thus constructed, an AC bias or a DC bias, or a bias voltage in which DC and AC are superposed between the developer carrier 11 and the surface of the electrostatic latent image carrier 15. May be applied.

Further, although the elastic blade is used as the pressing member, other shapes, for example, a blade having a tip made of synthetic resin attached to the tip thereof, a metal roller, an elastic roller or the like may be used.

According to the developing device 10, development is performed as follows. First, the developer 14 in the developer container 13 is conveyed by the rotation of the developer supply roller 17,
By the developer carrying member 11 and the charging blade 12, it is attached to the surface of the developer carrying member 11 extremely thinly. At this time, due to friction between the developer carrier 11 and the charging blade 12 and the developer, the developer particles are charged with the same polarity as the electrostatic image charge. The developer adhered to the surface of the developer carrier 11 adheres to the latent image of the electrostatic latent image carrier 15 which has been charged and exposed to form a visible image. Here, the developer carrier 11
The developer remaining on the top is scraped off by the recovery blade 16 and collected in the developer container 13.

FIG. 2 is a schematic diagram showing an example of a full-color image forming apparatus used in the image forming method of the present invention. In the image forming apparatus 20, a charging device 22, an exposing device 23, four sets of developing devices 24 to 27, a transfer device 29, a discharging lamp 30, and a cleaning roller 31 are arranged around the electrostatic latent image carrier 21. ing. The four developing devices 24 to 27 are capable of forming an image in the same manner as the device 10 shown in FIG. Further, the transfer medium holding body 28 installed at a position in contact with the electrostatic latent image carrier 21.
A transfer medium 32 is wound around the transfer medium 32, and the transfer medium 32 is guided to a fixing device 33.

According to the image forming apparatus 20, the image is
It is formed as follows. First, the charger 22 uniformly charges the surface of the electrostatic latent image carrier 21 and the exposure device 23 forms an electrostatic latent image. Next, the first developing device 24 causes the first color developer to adhere to the latent image to form a visible image, and the transfer medium 32 wound around the transfer medium holder 26.
Transfer to. Further, the second, third and fourth developing devices 25-2
Similarly, a visible image is formed using each of 7 and the obtained electrostatic image is transferred onto the transfer medium 32. After that, the transfer medium 32 is peeled from the transfer medium holder 28, guided to the fixing device 33, and the developer is heat-fused. In this way, a color image is formed on the transfer medium 32. The developer remaining on the electrostatic latent image carrier 21 without being transferred to the transfer medium 32 is discharged by the cleaning roller 31 after being discharged by the discharging lamp 30. Hereinafter, specific examples of the developer used in the present invention will be shown, and an image formed using these will be described. Unless otherwise specified, quantities are indicated by weight. Example 1 Monomer mixture A containing styrene monomer 82 parts Butyl acrylate 18 parts Acrylic acid 3 parts Water 100 parts Anion emulsifier (Neogen R) 1.5 parts Nonion emulsifier (Emulgen 950) 1 part Potassium persulfate 0 0.5 parts to aqueous solution mixture B and stirred at 70 ° C. for 6 hours.
Polymerization was carried out for a time to obtain a resin emulsion having a solid content of 50%. Next, resin emulsion 100 parts Phthalocyanine blue 2.0 parts

Was dispersed in water containing 0.1 part of a surfactant (sodium dodecylbenzenesulfonate), diethylamine was added to adjust the pH to 5.5, and the mixture was pre-stirred and dispersed with a TK homomixer. .

Then, 20% of the dispersion was heated to 90 ° C. with further stirring, 0.5 part of hydrogen peroxide was added and polymerized for 1 hour, and then the remaining dispersion was added and polymerized for another hour. After termination of the polymerization, the pH was adjusted to 7.0 with diethylamine, and the mixture was heated at 90 ° C. for 2 hours. This dispersion is filtered,
After washing and drying, polymer particles were obtained.

100 parts of the polymer particles and 0.5 part of colloidal silica (R972) were mixed by a ball mill, and fine particles were adhered to the surface of the polymer particles to obtain a toner having a 50% volume average particle diameter of 9.3 μm. It was This toner has a weight average molecular weight of 189000, a dispersion of 3.2, and a glass transition point of 6.
It was 0 ° C. Also, the average value of 10-point displacement tensile strength measured at 10 points is 0.74 kgf / mm ² Met.

An electrostatic image formed on the OPC photoreceptor was developed with the toner thus obtained using a non-magnetic contact one-component developing device as shown in FIG. 1 to complete the image. A high-definition image with no fogging and sharp edges was obtained. Further, when 10,000 sheets were run using this apparatus, neither toner aggregation nor image omission and fogging due to poor charging occurred. (Example 2)

Styrene-n-butyl methacrylate copolymer (glass transition point 62 ° C., weight average molecular weight 17500)
0) 98 parts and phthalocyanine blue 2 parts were kneaded with a pressure kneader for 1 hour, cooled, coarsely crushed with a hammer mill, finely crushed with a jet mill, and subjected to a wind classification method to obtain a 50% volume average particle diameter of 8.87 μm. Got fine powder.

To 100 parts of this fine powder, 0.5 part of colloidal silica (R972) was added and mixed well with a ball mill to deposit silica on the surface of the fine powder. The 10% displacement tensile strength of the obtained toner is 0.79 kgf / m.
m ² Met.

The toner thus obtained was used to develop the electrostatic image formed on the OPC photoreceptor by using a non-magnetic contact one-component developing device as shown in FIG. 1 to complete the image. A high-definition image with no fogging and sharp edges was obtained. Further, when 10,000 sheets were run using this apparatus, neither toner aggregation nor image omission and fogging due to poor charging occurred. (Example 3)

A resin emulsion similar to that obtained in Example 1.
Phthalocyanine blue, low against 100 parts of Rougeon
Damine 6G Lake, Arylacea of acetylacetanilide
Mix two parts of zo derivative and carbon black,
Cyan toner, magenta toner, and yellow toner
-, And black toner were manufactured in the same manner as in Example 1. So
The 10% displacement tensile strength of each is 0.7 for cyan toner.
4 kgf / mm² , Magenta toner 0.77kgf / m
m² , Yellow toner 0.75 kgf / mm² , And black
Toner 0.80kgf / mm² Met.

When these toners were applied to a full-color image forming apparatus as shown in FIG. 2, an image excellent in color reproducibility was obtained. When 5,000 sheets were run using this apparatus, neither toner aggregation nor image omission and fogging due to poor charging occurred. (Comparative example)

Except that the mixing ratio of the monomer mixture A was 80 parts of styrene monomer and 20 parts of butyl acrylate,
Toner particles were manufactured in the same manner as in Example 1. The weight average molecular weight of the polymerized particles was 181,000, and the 10% displacement tensile strength was 0.68 kgf / mm ^2. Met. When this toner was applied to an image forming apparatus similar to that of Example 1, the toner adhered to the elastic blade after running 5,000 sheets, fogging of non-image areas due to poor charging, and large amount of toner scattering inside the machine. Occurred. (Experimental example)

Various toners were produced by changing the resin composition, and the correlation between the 10% displacement tensile strength and the degree of adhesion of the toner to the charging blade was investigated, and the results are summarized in FIG. The sticking to the charging blade is represented by the number of white spots and black spots of the image after 5,000 running sheets, and the amount of fog in the non-image portion. In FIG.
FIG. 3B shows the correlation with the fog in the non-image area. Thus, the tensile strength is 0.7 kgf / mm ² With the above, there is almost no white spot and fogging of the image due to blade sticking and poor charging, but 0.7 kgf / mm ² It can be seen that when the value is less than 1, the value increases sharply.

[0044]

As described in detail above, according to the present invention,
10% tensile strength is 0.7 kgf / mm ² The above developers are used. This developer hardly sticks to the developer layer forming member or the developer carrying member, and can be stably triboelectrically charged. Therefore, problems such as fogging of the non-image area, scattering of the developer in the machine, and missing images due to defective conveyance of the developer do not occur. Therefore, it is suitable for color image formation using a non-magnetic one-component developer having a low softening point.

[Brief description of drawings]

FIG. 1 is a diagram showing an example of a developing device applicable to an image forming method of the present invention.

FIG. 2 is a diagram showing an example of a full-color image forming apparatus applicable to the image forming method of the present invention.

FIG. 3A is a diagram showing a correlation between 10% displacement tensile strength and the number of blank black dots when printing 5,000 sheets. (B) A diagram showing the correlation between the 10% displacement tensile strength and the fog amount in the non-image area when printing 5,000 sheets.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 10 ... Developing device, 11 ... Developer carrying body, 12 ... Charging blade 13 ... Developer container, 14 ... Nonmagnetic one-component developer, 15 ...
Electrostatic latent image carrier 16 ... Recovery blade, 17 ... Developer supply roller, 18 ...
Developer agitator 20 ... Color image forming apparatus, 21 ... Electrostatic latent image carrier, 2
2 ... Charging device 23 ... Exposure device, 24 ... First developing device, 25 ... Second developing device,
26 ... 3rd developing device 27 ... 4th developing device, 28 ... Transfer medium holding body, 29 ... Transfer device 30 ... Electrification lamp, 31 ... Cleaning roller, 32 ...
Transfer medium 33 ... Fixing device.

Continuation of the front page (51) Int.Cl. ⁵ Identification number Office reference number FI technical display location G03G 15/08 7810-2H

Claims (1)

[Claims] 1. Contact with an image carrier on which an electrostatic latent image is formed
This developer carrier is placed on the developer carrier placed at
Form a non-magnetic one-component developer layer using a pressure contact member that contacts the body
And the step of forming the electrostatic latent image carrier from the developer carrier.
Supplying a developer and developing the electrostatic latent image,
The developer is 0.7 kgf / mm² 10% displacement above
An image forming method having a tensile strength.