JPS63135972A - Developing device - Google Patents

Abstract

PURPOSE:To eliminate a base fogging and to obtain an image formation with high density and visibility, by providing a magnet roll arranged and rotated in the inside of a developing agent carrier, and a developing agent layer thickness regulating member consisting of a magnetic material arranged adjacently to the outer surface of the developing agent carrier. CONSTITUTION:The titled device is provided with a developing agent vessel which accommodates a two-component developing agent consisting of toner and a microcarrier, the developing agent carrier rotating in the vessel, a rotary magnet roll 3 arranged in the inside of the developing agent carrier, and the developing agent layer thickness regulating member 4, at least a part arranged adjacently to the outer surface of the developing agent carrier of which is constituted of the magnetic material. And the layer thickness of a developing agent layer carried to a latent image plane with the developing agent carrier and the magnet roll 3 is controlled under the influence of a magnetic function acting between the developing agent layer thickness regulating member 4, and the magnet roll 3. In such way, it is possible to eliminate the base fogging, and to obtain an image with high density and visibility, and especially to obtain the image without color turbidity when it is applied in a multilevel image formation.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a developing device for developing a latent image on an image forming body.
In particular, a developing device 2 for developing the latent image with a thin developer layer regulated under the influence of magnetic force! Regarding.

[Background of the invention]

Conventionally, in the fields of electrophotography, e-electronic printing, eTL recording, etc., there have been two types of devices for developing electrostatic latent images formed on image forming bodies using powder developers; It is broadly divided into those that use component developers.

When using a two-component developer, there is a powder developing device that uses atomized magnetic or non-magnetic toner as the main component, and a powder developing device that uses magnetic toner as the main component to convey the two-component developer using magnetic force. There is a developing VC apparatus which develops by bringing a magnetic brush into direct contact with the latent image surface.

In addition, when using a two-component developer, for example, the average particle size is 50 to 5.
Using a developer consisting of a magnetic carrier with a relatively large particle size of 00 μm and a non-magnetic toner with a relatively small particle size of, for example, an average particle size of 1 to 30 μm, the magnetic brush is directly applied to the latent image surface as in the case of using the above-mentioned -component developer. There is a developing device that develops by bringing it into contact with.

In such a developing device, toner directly contacts the entire surface of the latent image surface, that is, both the image and non-image areas of the latent image surface.
There is a problem.

Therefore, for example, Japanese Patent Application Laid-Open No. 55-18659 discloses that the two-component developer flow conveyed on the sleeve is thinner than the gap (100 to 500 μm) between the sleeve and the latent image surface.
For example, the M thickness regulating member is used to regulate the development scraps to be 100 μm or less, and a frequency! Peak voltage 800 to 1 below llz to ICI,
Zo.

A method and apparatus are described in which an oscillating electric field is formed by applying an alternating current/bias of V, and the oscillating electric field causes magnetic toner to fly toward the latent image surface for non-contact development.

According to the non-contact developing method and apparatus, even if the toner flies off due to the forward voltage of the AC bias and adheres to the non-image area, the toner is pulled back to the sleeve side by the reverse voltage, thereby preventing the occurrence of ground pressure. and clear images can be obtained. However, in the non-contact development method, in order to achieve effective development, it is required that the development scraps be made into a uniform m layer of, for example, 30 to 100 μm, which poses a major practical obstacle. For example, JP-A-57-2012
No. 55 discloses a thin film of a two-component developer in which the magnetic poles of a magnet roll disposed inside a sleeve face each other and magnetic toner is produced by a magnetic regulating member disposed close to the outer surface of the leap. Techniques for forming layers are disclosed. That is, it is described that the developer flow is regulated into a thin layer by a magnetic curtain formed between the magnetic regulating member and the magnetic pole of the magnet roll facing the magnetic regulating member.

However, the developing methods and i
A two-component developer is used in the machine, and the magnetic toner, which is the main component of the developer, is originally made by dispersing magnetic powder in a binder resin, and the resistance value and processability of the resulting toner vary. From this point of view, the content of the magnetic material contained in the toner is at most 501 m%.

Therefore, the magnetic attraction force of the magnet roll against the two-component developer flow conveyed on the sleeve is weak, and the developer flow is unstable and easily scatters.Even if such unstable developer flow is regulated by a magnetic curtain, Also, the effect of thinning is small,
There is also a problem with the uniformity of the regulated developed M layer.

In addition, the -component developer has insufficient triboelectric charging and the charging time of the toner is small, so not only in the case of contact development but also in non-contact developer, the toner flying due to the oscillating electric field is insufficient, resulting in insufficient development. There are problems such as insufficient density of the image obtained.

Furthermore, when the toner is used for forming color images, there are problems such as color turbidity due to the presence of magnetic material in the toner, making it difficult to form clear color images.

[Problem that the invention seeks to solve]

Therefore, there is a need for a developing VC device which has excellent conveyance properties due to magnetic force, fluidity, triboelectric charging properties, etc., and which performs non-contact development using a two-component developer that does not contain a magnetic substance in the toner. However, conventional two-component developers are composed of a relatively large magnetic carrier with an average particle size of 50 to 500 μm and a relatively small magnetic toner with an average particle size of 1 to 30 μm. It is difficult to make a thin layer with a developer containing the above, and since the carrier hardly vibrates due to the oscillating electric field, the toner adhering to the carrier may fly away ((unsuitable for non-contact development. As a result of extensive research, they discovered a developing device that is capable of developing a thin layer using a two-component developer, and completed the present invention.

[Means for solving problems]

(Objective of the Invention) An object of the present invention is to provide a developing device that is free from blurring, is capable of forming high-density and clear images, and is suitable for color development.

(Structure of the Invention) The above object is to provide a developer container containing a two-component developer consisting of toner and microcarriers, a developer transport carrier that rotates within the container, and a developer transport carrier disposed inside the developer transport carrier. r
a, a rotating magnet roll, and a developer layer thickness regulating member (a part of which is made of a magnetic material) disposed close to the outer surface of the developer transport carrier; A developing device that regulates the layer thickness of a developer layer transported to a latent image surface by a developer transport carrier and the magnet roll under the influence of a magnetic action acting between the developer layer thickness regulating member and the magnet roll, This is particularly achieved by a developing device that performs non-contact development.

(Detailed Description of the Invention) That is, in the developing device of the present invention, a two-component developer consisting of a magnetic microcarrier with an average particle size of 15 μm or more and less than 50 μm and a non-magnetic toner with an average particle size of 1 to 30 μm is used.
I can stay. The average particle size referred to here is the number-based average particle size (hereinafter omitted). Here, the douya in the two-component developer is usually a ferromagnetic material, and the component ratio of the magnetic material in the developer is two-component. Since the amount is larger than that of the developer, the magnetic force acting between the layer thickness regulating member and the magnet roll becomes stronger, and the developer layer thickness is more effectively regulated.

It is presumed that the thickness of the developer layer of 9A is achieved as follows.

That is, the developer flow that is conveyed on the sleeve and attempts to pass through the gap between the layer thickness regulating member and the developer transport carrier (hereinafter referred to as a sleeve) is not limited to the mechanical layer thickness regulation by the gap. The layer thickness is regulated by the magnetic action of the layer thickness regulating member generated in response to the alternating N and S magnetic poles of the rotating magnet roll.

At this time, the upper layer of the developer flow is suppressed by the magnetic action of the magnetic pole generated in the layer thickness regulating member, and only the remaining lower developer flows into the developing area due to the magnetic attraction force and the conveyance force of the sleeve. transported.

(Thus, the developer layer can be made more uniform and thinner than when conventional mechanical layer thickness regulating means are used. In the present invention, the magnet roll is placed in the same direction as the sleeve or Since it rotates in the opposite direction, an oscillating magnetic field is generated, which has the effect of automatically removing foreign matter interposed between the sleeve and the layer thickness regulating member.

In the developing device of the present invention, since the carrier for the developer contained in the device is a microcarrier, it vibrates relatively easily due to the oscillating electric field, so that the toner adhering to the carrier is removed. It becomes easier to fly toward the image forming body, and as a result, non-contact development becomes possible.

As the developing device of the present invention, for example, one having the following structure is used. In the figure, 1 is an image forming body rotating in the direction of the arrow;
is a non-magnetic sleeve that rotates in the direction of the arrow; 3 is a magnet roll having alternating N and S magnetic poles; 4 is a magnetic layer thickness regulating member arranged close to the sleeve 2; 5 is a developer reservoir. , 6 is an agitator, 7 is a roller for replenishing the toner T for replenishment, 8 is a toner hopper, and 9 is a DC bias required for preventing fog during normal development or a DC bias necessary for reverse development is applied to the sleeve 2. 10 is a power source for applying an AC bias to the sleeve 2 for non-contact development, and R is a protective resistor. A two-component developer consisting of microcarriers and toner is replenished by a quantitative replenishment roller ruff, mixed by agitation n6, and frictionally charged. The developer layer is conveyed while being formed, and is regulated by the developer layer thickness regulating member 4 midway through to become a thin layer, and then conveyed to the development area.

Development in the development area K is performed by applying an alternating current bias voltage to make the toner fly toward the image forming body 1 and developing the electrostatic latent image on the surface of the image forming body 1 without contact. be done.

Here, the gap d between the image forming body 1 and the sleeve 2 is set to 11 or less, and the gap between the developer layer thickness regulating member 4 and the sleeve 2 is smaller than the gap d, preferably 500 μm or less. Furthermore, the developer layer in the development area K is formed in the gap d.
smaller, preferably 400 μm or less, and 100 μm
The layer thickness exceeds m.

When the layer thickness is less than 100 μm, the thickness of the developer layer becomes non-uniform, and unlike in the case of a -component developer, a considerable amount of carrier coexists, resulting in an insufficient amount of toner and a decrease in image density. Also, if it exceeds 400 μm, the developer layer will be too thick.
The action of the alternating current bias on the toner particles on the surface is reduced, making them difficult to fly, and the non-contact development effect is reduced. The frequency of the AC bias is greater than I KHz and less than 10 KHz, and its peak voltage is 500 V to 4 KV. If the frequency of the alternating current bias is less than I KHz, toner flight will not be sufficient, and if it exceeds 10 Kllz, toner flight will not be able to follow the frequency of the oscillating electric field, conversely image density will decrease, and carrier adhesion may occur again. become. Further, if the peak voltage is less than 500 V, toner flight will be insufficient, and if it exceeds 4 KV, carrier adhesion will occur, which is undesirable.

The direct current bias from the master die 19 has a polarity opposite to that of the toner in regular development, and is usually set at 50 to 500 V, to prevent toner from adhering to non-image areas and reduce blurring. When reversal development is performed using toner having the same polarity as the latent image charge on the image forming member, a DC bias having the same polarity as the toner and close to the surface potential of the image forming member is applied.

Next, the developer layer thickness regulating member 4 is made of a magnetic material at least in part, and cooperates with the magnet roll 3 built in the sleeve 2 to magnetically regulate the developer flow and form a thin layer. be made into Such developer/! ! The I-thickness regulating member 4 can take various forms shown in FIGS. 2 to 4, for example.

(a) to (e) in Fig. 2 are regulating members made only of magnetic materials of various shapes, which are disposed on the sleeve 2 rotating in the direction of the arrow, and the magnetic force of the magnet roll 3 rotating inside the sleeve 2. 6. Figure 2 (a) shows a regulating member with a rectangular cross section whose lower surface is arranged parallel to the plane of the sleeve 2, and Figure 2 (b) shows a regulating member with a wedge-shaped cross section. The tip of the protrusion at the lower end has a plane parallel to the plane of the sleeve 2.

FIG. 2(c) shows that the lower end of the sleeve 2 has an inclined surface that descends toward the upstream side of the sleeve 2, and magnetically regulates the regulated developer flow mainly near the descending tip. By flowing out onto the downwardly inclined surface, the flow of the developer is smoothed out, and the build-up of dust and the like is prevented. PIS2 diagram (d) has a configuration in which a plurality of regulating members 41 and 42 are provided and the regulation ends in stages. In addition, FIG. 2(e) has an inclined surface that descends toward the downstream side of the sleeve 2, and a flat surface parallel to the surface of the sleeve 2 at the lower end, so that the developer smoothly flows into the regulating portion of the regulating member 4. In Figure 3, the magnetic material is placed in one of the regulating members.
Examples of use as component materials are shown in Figures 3(f) to (k).
) are each composed of a magnetic part 4a and a magnetic part 4b. The shape and arrangement of the magnetic portion 4b are determined by the 1'fiM of the developer,
It is selected depending on the rotational speed of the image forming body 1, the magnet roll 3 and/or the sleeve 2, the strength of the magnetic field of the magnetic pole of the magnet roll, etc.

The thickness of the layer thickness regulating portion varies depending on the material and shape, but it is usually in the range of 0.5 to 5 mm.

The magnetic material used for the developer layer regulating member 4 shown in FIGS. 2 and 3 above is a substance that is strongly magnetized in the direction of a magnetic field, such as metals such as iron, nickel, and cobalt, or oxides thereof. , alloys or compounds containing iron, cobalt, nickel, etc., such as ferrite, magnetite, and hematite, or Mn-Cu, which does not contain ferromagnetic substances but becomes ferromagnetic by appropriate heat treatment.
A Heusler alloy such as -Al or Mn-Cu-8n is used.

The non-magnetic material 4 of the regulating member 4 may be plastic, A1. Non-magnetic metals such as Cu, rubber, etc. are used.

Further, the magnetic material 4 may be made of a paramagnetic magnet6.By the way, the various regulating members of the present invention have mechanical layer thickness regulation by a narrow gap d between the tip of the regulating member and the sleeve surface, and a magnetic roll. Strength Hl of the magnetic field between the layer thickness regulating members: regulated by the magnetic regulation based on. By configuring the regulating member in this way, there are disadvantages that may occur if only illegal regulation is used, such as (1) it is difficult to uniformly and accurately regulate narrow gaps of 500 μm or less, and (2) developer (3) The developer flow expands after regulation, and (3) the developer flow expands after regulation.
Each l! such as the formation of an unexpectedly thick, uneven and rough developer layer! 11 adverse effects are greatly alleviated, and a uniform thin developer layer necessary for non-contacting can be obtained.

In the present invention, it is preferable that 5 to 60% of the amount of developer regulated by the regulation member is due to the magnetic regulation, and therefore the strength of the magnetic field between the magnet roll and the magnetic regulation member is 50 to 700 Gauss. It is better to

Next, the above figures t52 and tjIJ3 are fixed type layer thickness regulating members, but the layer thickness regulating member shown in Fig. 4 described below contains a magnetic material and has a rotating body that rotates in the opposite direction to the sleeve, so The developer is caused to flow outward by the rotating body, and the developer is flowed out to the outside more smoothly than in the case of FIGS. 2 and 3.
Allows for debris formation to be achieved. In this configuration, the developer flow is regulated over a relatively wide area of the surface of the rotating body, so that no undue impact is applied to the developer flow, and since no eddies are generated, uniform layer thickness regulation is achieved. Further, there is an advantage that foreign matter interposed between the sleeve and the regulating member can be actively removed.

The regulating member shown in Fig. 154 (1) is configured to rotate the magnetic roll 11 on the surface of the sleeve 2 with the pongee 12 as the center, and regulates the developer layer by a rotating magnetic field, so that the excess developer is directed in the direction of the arrow. It is separated and conveyed upward by a rotating magnetic roll 11 and scraped off by a blade 15. Note that the magnetic roll 11 may be a paramagnetic magnet.

Next, the regulating member shown in FIGS. 4(,) and (n) is configured to rotate a non-magnetic sleeve 14 around the outer periphery of a fixed rolled magnet 13, and remove excess developer from the rotating sleeve 14. They are separated and conveyed upward for removal.

In FIG. 4(-) above, the developer conveyed upward by the sleeve 14 is scraped off by the blade 15, but in FIG.
), a blade magnet 16 is provided in place of the blade 15, and excess developer is scraped off by the repulsive magnetic field of the magnetic pole of the blade magnet 16, which has the same polarity as the magnetic pole of the rolled magnet 13.

The above is the explanation of the structure of the developer layer thickness regulating member according to the present invention, and the two-component developer containing the microcarrier according to the present invention will be explained below.

(Tos -) The toner, which is a component of the two-component developer, is usually prepared by mixing an appropriate amount of a coloring agent and, if necessary, a charge control agent, a mold release agent, etc. in a buying resin, melting, kneading, and cooling. It is obtained by post-pulverization and classification to obtain the desired particle size.

Examples of the buying resin include polyester resin and styrene/acrylic resin.

The polyester resin is obtained by polycondensation of furfur and carboxylic acid, and the alcohols used include, for example, ethylene glycol, diethylene glycol, triethylene glycol, 1,2-propylene glycol, 1,3-propylene glycol, 1.4-
Fols such as butanediol, neopentyl glycol, 1,4-butanediol, 1,4-bis(hydroxymethyl)cyclohexane, bis7er/-A1, hydrogenated bis7er/-A, polyoxyethylene Bisphenol A, polyoxypropylene and sulfur 7/-ru A
This concludes by listing F's etherified bis-7-enols and other dihydric alcohol monomers.

Further, examples of the carboxylic acid include maleic acid, 7-maric acid, mesaconic acid, citraconic acid, itaconic acid, glutaconic acid, 7-talic acid, isophthalic acid, terephthalic acid, cyclohexanedicarponic acid, succinic acid, 7-dipic acid, Examples include cepacic acid, malonic acid, anhydrides of these acids, lower alkyl ester/leic acid dimers, and other divalent organic acid monomers.

As the polyester resin preferably used in the present invention, it is also suitable to use a polymer containing a component of the above-mentioned trifunctional or higher polyfunctional monomer. Examples of trivalent or higher polyhydric alcohol monomers that are such polyfunctional monomers include sorbitol, 1.2,3.6-hexanetetrol, 1,4-sorbitan, pentaerythritol, dipentaerythritol, Tripentaerythritol, sucrose, 1 + 2 + 4-butanetriol, 1.2
．． 5-pentanetriol, glycerol, 2-methylpropanetriol, 2-methyl-1,2,4-butanetriol, trimethylolethane, trimethylolpropane,! , 3.5-) lyhydroxymethylbenzene,
Others can be mentioned. In addition, examples of trivalent or higher polyvalent carboxylic acid monomers include 1.2.4-benzenetricarboxylic acid, 1.3.5-benzenetricarboxylic acid, 1,2.4-cyclohetosantricarboxylic acid, 2,5
．． 7-? 7-talenttricarboxylic acid, 1,2.4-butanetricarboxylic acid, 1゜2.5-hexanetricarboxylic acid, 1.3-nocarboxy-2-methyl-2-methylenecarboxypropane, tetra(methylenecarboxyl)
Methane, 1°2.7.8-octanetetracarboxylic acid,
Mention may be made of embol trimer acids and anhydrides of these acids, among others.

The above styrene/acrylic 1FJf plate is, for example, a, β-
Contains an unsaturated ethylenic monomer as a constituent unit, and has a weight average molecular weight of 11 (MW) and a number average molecular weight (M n)
Is the ratio (M w / M n) of 3.5 or more? JF fat can be used.

Specific examples of α,β-unsaturated ethylenic monomers include styrene, 0-methylstyrene, I-methylstyrene, p-methylstyrene, α-methylstyrene, p-ethylstyrene, 2,4-methylstyrene, Methylstyrene, p-n-butylstyrene, p-tert-butyrestyrene, p-
n-hexylstyrene, 9-n-octylstyrene, p
-r+-/nylstyrene, p-r+-decylstyrene,
1) -〇-dodecylstyrene, p-methoxystyrene,
p-phenylstyrene, p-chlorostyrene, 3,4-
Aromatic vinyl monomers such as nochlorostyrene; e.g. methyl acrylate, ethyl acrylate, acrylic l'
ln-butyl, isobutyl acrylate, propyl acrylate, acrylic FR n-octyl, dodecyl acrylate, lauryl acrylate, 2-ethylhexyl acrylate, stearyl acrylate, 2-chloroethyl acrylate, ethyl acrylate, α-chloroacrylic fi Acrylic acid esters such as /chill; methaphrylmimethyl,
Ethyl methacrylate, propyl methacrylate, l'1ln-butyl methacrylate, isobutyl methacrylate, n-octyl methacrylate, dodecyl methacrylate, lauryl taacrylate, methacrylic 1! ! 2
-Ethylhexyl, stearyl methacrylate, methacrylic I'! Ivy acrylic acid esters such as 27enyl, dimethyl 7-minoethyl methacrylate, and noethyl 7-minoethyl methacrylate; Vinyl halides such as vinyl chloride, vinylidene chloride, vinyl bromide, and vinyl fluoride; vinyl acetate, propion Examples include vinyl esters such as vinyl acid, vinyl benzoate, and vinyl butyrate; and others.

Next, the coloring agents mixed into the toner include carbon black, aniline black, 7-arnet black,
There are black pigments such as lamp black, and blue or cyan pigments such as aniline blue, carfoil blue, methylene blue, phthalocyanine blue, etc., and red or magenta dyes such as DuPont Oil Left, Roseben LFL, etc. , pigment red, rhodanine, etc. Yellow 2 pigments include auramine, kudrazine, benone derivatives, etc., and binder m s toon! It contains 1 to 20 parts by weight per part.

Furthermore, a charge control agent may be added to control the coordinate chargeability of the toner.For black toner, a conventionally known general charge control agent may be used, but for chromatic toner, the color tone of the toner may be controlled. A charge control agent that is white, colorless, or close to colorless and does not cause any damage is selected. Examples of such charge control agents include JP-A No. 59-88745, vf JP-A No. 59-8
8743, JP 11i 59-79256, JP 59-78362, JP 59-228259, JP 59-124344, and Japanese Patent Application 1986-2.
Specification No. 1654 (Negative charge control agent) and JP-A-51-9
No. 456, JP-A No. 59-204851, Special 1m [59
-204850 and vflm [59-177571 (positive charge control agent)]. The charge control agent is contained in an amount of 0 to 5 parts by weight per 100 parts by weight of the toner's binding resin.

Next, a release agent is used if necessary to prevent the toner from offsetting to the fixing roller and from adhering to the carrier.

Examples of such mold release agents include polyolefins, fatty acid metal salts, fatty acid esters, partially saponified fatty acid esters,
Examples include higher fatty acids, higher alcohols, liquid or solid paraffin waxes, amide waxes, polyhydric alcohol esters, silicone varnishes, and aliphatic 70 carbons.

The above mold release agents can be used alone or in combination of two or more.

Examples of the polyolefin include polypropylene,
Resins such as polyethylene and polybutene, JIS
The softening point when measured by the ring and ball method specified in K 2531-1960 is 80 to 180°C, preferably 100°C.
~160°C. As the fatty acid metal salt,
For example, maleic acid and metal salts of zinc, magnesium, calcium, etc.; stearic acid and metal salts of zinc, cadmium, barium, lead, iron, nickel, cobal), copper, fluminilum, magnesium, etc.; dibasic lead stearate; Metal salts of oleic acid with zinc, magnesium, iron, cobalt, copper, lead, calcium, etc.; metal salts of valmitic acid with aluminum, calcium, etc.; lead caprylate; lead caproate; calcium linoleate; lysylinate and zinc , metal salts with cadmium, etc., and mixtures thereof. Examples of the fatty acid ester include ethyl maleate, butyl maleate, methyl stearate, methyl stearate, cetyl palmitate, and ethylene glycol montanate. Examples of the partially saponified fatty acid ester include partially saponified calcium esters of montanic acid.

Examples of the higher fatty acids include dodecanoic acid, phosphoric acid, myristic acid, palmitic acid, stearic acid, oleic acid, 7-alic acid, linoleic acid, arachidic acid, behenic acid, lignoceric acid, and ceracolein f11. and mixtures thereof. Examples of the higher alcohol include dodecylfluorol, lauryl alcohol, myristyl alcohol, palmityl alcohol, stearyl alcohol, aralkyl alcohol, and behenyl alcohol. Examples of the paraffin wax include natural paraffin, microwax, synthetic paraffin, and chlorinated hydrocarbons. Examples of the 7-amide waxes include stearin pH 7-amide, oleic acid amide, palmitic acid 7-amide, lauric acid amide, behenic acid amide, methylene bis-stearamide, and ethylene bis-stearamide. Examples of the polyhydric alcohol ester include glycerin stearate, glycerin wasylate, glycerin monobehenate, sorbitan monostearate, propylene glycol monostearate, and sorbitan triolate. Examples of the silicone varnish include methyl silicone varnish, phenyl silicone varnish, and the like.

Examples of the aliphatic 70-carbon include low-polymerized compounds such as 47-ethylene, 67-propylene, and fluorine-containing surfactants described in JP-A-53-124428.

The amount of these mold release agents used is as follows:
Parts are 1 to 10 parts by weight.

In the case of a chromatic toner among the toners mentioned above, since the coloring agent affects the performance of the toner, for example, the amount of charge of the toner, the specific resistance is 104 to 10I5Ω-+) and the grinding and 1 hour addition are selected as appropriate. There is a need to.

The toner obtained in this way has a specific resistance of 1 in order to obtain high image quality.
08 ΩC- or more, preferably 10'2 Ωem or more, more preferably 1014 Ωcm or more, and the mfl average particle size is 1 to 1.
The fine particle toner is preferably 30 μm, and is suitable for non-contact development with a thin original developer layer, which will be described later.

(Carrier) The carrier, which is another component of the two-component developer, uses magnetic particles, preferably spherical magnetic particles, as a core material, and a resin solution is dip coated or spray coated on the core material and dried. Alternatively, a coated carrier may be used in which a thin layer of resin is formed by a spray drying method or the like.

As the magnetic material serving as the core material, the same magnetic material as that used for the development scrap thickness regulating member can be used, but ferrite is preferably used from the viewpoints of toner transportability, durability, developability, etc.

The characteristics of the core material include specific resistance of lXl0' to lXl
0"0cm, more preferably IXIO"-IXIO
ΩC-1 saturation magnetization is preferably 10-40 emu/g, preferably 15-30e+++u/g, 10e
If it is less than 1/g, the magnetization of the core material becomes small, the conveyance property decreases, and the image density becomes low. When it exceeds 40 emu/g, the carrier density on the sleeve decreases, development efficiency decreases, and image density decreases. Furthermore, it becomes difficult to form a thin layer. Coercive force is 0.1-1000e, especially 10-7
A range of 0.00 e is preferable; below 0.10 e, the magnetization of the carrier is de-energized quickly, resulting in poor conveyance.

If it is 1000e or more, the transportability becomes large and carrier scattering tends to occur.

Further, the specific gravity of the core material is 4.0 to 5.5, particularly 4.2 to 5.
0 is preferable; if it is 4.0 or less, the carrier is light and easily scatters. If it is 5.5 or more, the conveyance property will deteriorate.

The porosity is preferably 1 to 10%. If it is less than 1%, the sintering temperature will be high, the time will be long and the cost will be high. If it is more than 10%, the strength will be low and the durability of the carrier will be poor.

Examples of coating resins include styrene-acrylic resin, silicone resin, fluororesin, acrylic resin, polyester resin, epoxy resin, vinyl chloride/vinyl acetate copolymer, and nitrogen-containing TA4 resin. Inorganic materials such as glass and ceramics can also be used.

Usually, rJ (Jll?
is used. The thickness of these coatings is 0.1~
The thickness is preferably 10 μm, preferably 0.3 to 3 μm, and may be set to a value that provides sufficient insulation and stable characteristics.

In addition, when using a resin-coated carrier, even if the carrier has a small particle size, it has good fluidity, so even if the layer thickness is regulated by the M thickness regulating member, a uniform developer layer cannot be formed on the sleeve. Furthermore, the mold releasability is good, and there are effects such as no filming of toner on the carrier even when subjected to strong pressure. The carrier thus obtained has a resistivity of 10·90111 or more, preferably 10'2Ωel1
Above, more preferably 1014 ΩcllI or more,
It is preferable that the 50% diameter based on the weight is usually 20 to 60 μ plow, and the 50% diameter R based on the ffl amount of the carrier
(μm) and carrier magnetization M (e ring u/am') preferably has the following relational expression.

The formula is 30≦M≦−8R+150, where 10≦R≦150, preferably 20≦R≦60, and the measurement is performed under the application of a magnetic field of t, ooo Oersted.

Next, the developer of the present invention can be obtained by mixing appropriate amounts of the carrier and toner, but the mixing ratio varies depending on the particle size, that is, the surface area ratio, of the carrier+77 and 1 toners.In particular, the larger the carrier, the more the toner The mixing ratio is reduced.

For example, the ratio of the total area Sc of carrier to the total area St of toner in a unit volume of developer St/5c=0.5 to 2
The weight ratio is preferably in the range of 5 to 20 parts by weight toner per 100 parts by weight of carrier.

The resistance values listed above are determined by placing the particles in a container with a cross-sectional area of 0.50 cm" and tapping, then applying a load of 1 k!r/em" on the packed particles, which also serves as a load. 1,000V/a between the top electrode and the bottom electrode
This value is obtained by reading the current value when a voltage that generates an electric field of m is applied.

Further, the average particle diameter is a 50% diameter on a weight basis as measured by Coulter Kajunta (manufactured by Coulter Inc.).

〔Example〕

EXAMPLES The present invention will be specifically explained below with reference to Examples, but the embodiments of the present invention are not limited thereto.

(Embodiment 1) FIG. IjtJ5 is a cross-sectional view of a main part of an image forming apparatus for explaining this embodiment, and the same components as in FIG. 1 are given the same reference numerals. 2
0 is a non-contact developing device having the same configuration as in Fig. fjS1 (however, the magnet roll rotates in the opposite direction to the sleeve), and the magnetic layer thickness regulating member 1111 shown in Fig. 3 (J) is installed as the developer layer thickness regulating member 4. ing. 21 is a corona charger, L image exposure, 2
2 is the pre-transfer exposure lamp, 23 is the transfer electrode, and 24 is the separation?
1 pole, p a rotating 'I'f paper, and 25 a cleaning static eliminator which is connected to the static eliminator electrode 25a and the static eliminator lamp b. 26
is a cleaning device having a cleaning blade 26a and a bias roller 26b.

Image formation is performed in this apparatus as follows. After the surface of the image forming body 10 is charged with a uniform potential by the corona charger 21, imagewise exposure is performed to form a latent image. This latent image is developed by the developing device 20 under conditions described below to obtain a toner image. After this toner image is uniformly exposed by the pre-transfer exposure lamp 22, it is transferred onto the conveyed transfer paper P at a predetermined timing by the action of the pine copying pole 23, and the toner paper P is transferred by the action of the separation 1i24. Image forming body 10
The toner image is separated from the transfer paper P and further transferred by a fixing device (not shown), and is fixed onto the transfer paper P and discharged outside the machine. On the other hand, the surface of the image forming body 10 after being transferred goes up to the removing electrode 25a and the removing lamp 25b of the pre-cleaning removal device 25 and is neutralized, and then is cleaned by the blade 26a of the cleaning device 26, and the toner that falls out at this time is removed. A bias roller 26 rotates when a bias is applied to it.
b, and is discharged by a discharge screw conveyor.

Next, the developer used will be explained.

Make toner as follows! 'l-reru.

Polyester υ (fat U X -K 120p' 10
0 weight i part (manufactured by Kako Soap Co., Ltd.) Volip a pyrene 860IJ8/1 (Sanyo Kasei Ei Co., Ltd. 91) Carbon black Mogul LIO// (manufactured by Capot Co., Ltd.) were mixed in a Henschel mixer, and then heated to 140°C with three rolls. After sufficiently kneading at a temperature of
of colorant particles are obtained. 0 parts of hydrophobic fine silica R-812 (manufactured by Nippon Seven Korosil Co., Ltd.) was added to 100 parts of the coloring material particles.
．． A toner is obtained by adding 4 parts by weight and dispersing and mixing in a type mixer.

The main physical properties of this toner are resistivity of approximately 1014Ωe1
m, average particle diameter of 10 μm, and specific gravity of 1.2 g/c+e3.

The carrier is produced as follows.

Spherical man-zinc 7-ite particles (TDK 91)
On the other hand, a carrier is obtained by coating the particle surface with styrene-acrylic resin to a thickness of 1.5 μm using a Subirahuter. The main physical properties are an average particle diameter of 30 μm, a resistivity of 1013 Ωcm, a magnetization of 85e so u/am, and a specific gravity of 4.6 g/am'.

A desired developer is obtained by mixing 10 parts by weight of such a donor and 90 parts by weight of a carrier. If this is sufficiently stirred, the average charge amount of the toner will be about -20 μC/g.

As a result of repeating 1,000 times of 11 image formation under the conditions shown in Table 1, a high-density and clear image was obtained with no occurrence of ground force.

(Comparative Example) The image forming apparatus shown in FIG. 5 of Example 1 was used, but instead of the two-component developer contained in the developing device 20, a one-component developer with the following formulation was used, and an image was formed under the image forming conditions shown in Table 2. Formation was carried out.

Developer formulation polyester wood Wfl U X -K 120. 1
00 parts by weight Magnetite powder (average particle size reduced by 0.1 μm) 40 parts by weight Polypropylene 660p 6 parts 1 part Carbon black 8 parts by weight Colored particles were obtained, and hydrophobic silica R was added to 100 parts by weight of the colored particles.
-8120.4 weight was added to obtain a developer of this comparative example.

Margin No. 23 As a result of repeated image formation under the above conditions, there was overall density unevenness from the initial stage, which is presumed to be because the regulation by the developer layer thickness regulating member was not necessarily uniform.

(Example 2) FIG. 6(a) is a cross-sectional view of main parts of a multicolor image forming apparatus explaining this example, and FIGS. 6(b) and (c) are a writing device and a FIG. 3 is a cross-sectional view showing the developing device.

The multicolor image forming apparatus shown in FIG. 6(a) operates as follows. The II image input section IN includes an illumination plateau 31, a Mitsu-32, a lens 33, and a -dimensional color CCDtjlk image element 34 that are integrated into a unit, and the image input section IN is moved in the direction of the arrow X by a drive device (not shown). Move and CCD
The image sensor 34 reads the original.

The image information read by the image input section IN is sent to the image processing section T.
R is used to convert the data into data suitable for recording.

The laser optical system 36 forms a latent image on the image forming body 1 in the following manner based on the above image data, and this latent image is developed to form a toner image on the image forming body. The surface of the image forming body 1 is uniformly charged by the scorotron charging electrode 41. Subsequently, the image forming body 1 is irradiated with image exposure light from the laser beam system 36 through the lens in accordance with the recorded data. In this way, an e-electronic latent image is formed. This electrostatic latent image is developed by a developing device A containing yellow toner. This developing device A has the configuration shown in FIG. 6(c) below.

The image forming body 1 on which the toner image has been formed is uniformly charged again by the Suflotron charging electrode and subjected to image exposure according to recorded data of another color component. The formed electrostatic latent image is developed by a developing device B containing magenta toner. As a result, a two-color toner image of yellow toner and magenta toner is formed on the image forming body 1. Thereafter, cyan toner and black toner are developed in a similar manner using developing positions C and D, and a four-color toner image is formed on the image forming member 1. Note that the developing devices B, C, and D all have the same structure as the developing device A.

The multicolor toner image thus obtained is transferred to the exposure lamp 4.
2, the transfer pole 43 is removed and transferred easily.
The image is transferred onto the recording paper P fed from the paper feeding device 48 in synchronization with the image formation.

The recording paper P is separated from the image forming body 1 by the separation pole 44,
The image is fixed by a fixing device 45. On the other hand, the image forming body 1 has a removal electrode 4
6 and cleaning equipment r! 147.

The cleaning device 47 has a cleaning blade 47a and a seven-ar brush 47c. These are kept out of contact with the image forming body 1 during image formation, and when a multicolor image is formed on the image forming body 1, they come into contact with the image forming body 1 after the transfer and scrape off the toner remaining after transfer. . Thereafter, the cleaning blade 47a separates from the image forming body 1, and a little later, the 7-hoop run 47c separates from the image forming body 1. 7r-The brush 47c functions to remove toner remaining on the image forming body 1 when the cleaning blade 47a leaves the image forming body 1. 4
7b is the toner scraped off by the blade 47a II! It is a roller that collects.

The laser optical system 36 is shown at 37 in Figure 0 in Figure 6 (B).
is a semiconductor laser oscillator, 38 is a rotating polygon mirror, and 39 is f
It is a θ lens.

Further, the developing device ftA shown in FIG. 6(c) is composed of parts vI that are almost the same as the developing device shown in FIG. 1, but it is necessary to arrange four developing devices around the image forming body 1. Therefore, it has a more compact structure.

In addition, a magnetic plate of Pt52 shown in FIG.
is fixed, and the regulating member 4 is disposed facing the magnetic pole N of the magnet roll 3.

The carrier used here was the same as in Example 1.

In addition, the toner is the same black toner as in Example 1,
In other toners, each colorant was used instead of carbon black. In other words, yellow toner contains auramine,
For the magenta toner, copper 7-lysyanine is used in the rhodamine B1 cyan toner. The mixing ratio of toner and carrier was 1:9 (weight ratio), fl!
The working conditions are shown in Table Pt53.

When a multicolor image was formed by developing yellow, magenta, cyan, and black in this order under the conditions shown in Table 3 of Table V, an image with high density and vivid color tone was obtained without any blurring.

(Example 3) In place of the layer thickness regulating member (J) of Example 1, a layer thickness regulating member (
-) was used in the same developing device as in Example 1, and an image was formed in the same manner as in Example 1 using the image forming apparatus shown in FIG. However, the M thickness regulating member (-) has a diameter of 15 mm, rotates the sleeve 14 in the direction of the arrow at a circumferential speed of 250 mm/see (same circumferential speed as the sleeve 2 of the developing roll, but in the opposite direction), and has a distance between it and the sleeve 2 of 100 μm. It was made to work as . As a result, a good image was obtained with no ground blur, image unevenness, dotted or streaky image defects.

(Example 4) The magnet roll 3 was rotated at 1+0OOr, p, n in the same direction as the sleeve in the developing f1 positions A, B, C, and D having the structure shown in FIG. 6 (c) used in Example 2. A multicolor image was formed in the same manner as in Example 2, and it was found to have high density and color 'I!' with no dot or streak defects or blurring. A 4ty clear image was obtained.

〔Effect of the invention〕

As is clear from the above description, the developing device of the present invention can produce high-density, clear images without blurring, and especially when applied to multicolor image formation, can produce clear images with no color turbidity. can get.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing an example of the developing device of the present invention, FIGS. 2 to 4 are sectional views showing a specific example of a developer layer thickness regulating member that can be used in the present invention, and FIG. 5 is an embodiment. 1 image form I! 6(a) is a sectional view of essential parts of the image forming apparatus of Example 2, and FIGS. 6(b) and 6(c) are sectional views of the main parts of the image forming apparatus of FIG. 6(a). FIG. 3 is a new view of the writing device and developing device that are incorporated. 1 ---- One image forming member (photosensitive drum) 2 ----
- Sleeve, 3 ---- One magnet roll 4 ----
1. Developer layer thickness regulating member 6 --- 1. Agitator, ? ------1 Toner replenishment roller 9.10--1--Bias? Li source 12---1M thickness regulating member 13 made of a monomagnetic roll
-----7r! Fixed magnet body 14 as a thickness regulating member
----- Sleeve 20 as a further thickness regulating member, A,
[3, C, D-----Developing device 21.41----
-One charger, L---One exposure light 22.42--
---One transfer moe exposure lamp 23.43---One transfer device +
24144 ---- 1 separator 25.46 ------- Static eliminator before cleaning 26.47 ---- Cleaning device IN ---- 1 image input section, 34 -------
CCD image sensor TR----1 image processing section, 36--
---Writing device applicant: Konishiroku Photo Industry Co., Ltd. Figure 4 (n) Figure 5 Procedure Shinichi Seisho February 20, 1988

Claims (6)

[Claims] (1) A developer container containing a two-component developer consisting of toner and microcarriers, a rotating developer transport carrier located within the container, and a rotating magnet roll placed inside the developer transport carrier. and a developer layer thickness regulating member, at least a part of which is made of a magnetic material, provided close to the outer surface of the developer transport carrier, and the developer layer thickness regulating member is provided close to the outer surface of the developer transport carrier, and the developer layer thickness regulating member is provided close to the outer surface of the developer transport carrier, and the developer layer thickness regulating member is formed of a magnetic material. A developing device characterized in that the thickness of a developer layer conveyed to an image plane is regulated under the influence of a magnetic effect acting between the developer layer thickness regulating member and the magnet roll. (2) The developing device according to claim 1, wherein the latent image surface is developed in a non-contact manner under an oscillating electric field generated by applying an alternating current bias to a gap between the latent image surface and the developer transport carrier. . (3) If the frequency of the AC bias exceeds 1KHz
The developing device according to claim 2, wherein the developing device has a peak voltage of 500 V to 4 KV. (4) The developing device according to claim 1, wherein the developer layer on the latent image surface has a layer thickness smaller than the gap between the developer transport carrier and the latent image surface, 500 μm or less, and exceeding 100 μm. . (5) Claim 1, wherein the gap between the developer transport carrier and the layer thickness regulating member is 700 μm or less, and is greater than or equal to the maximum particle size of microcarriers in the two-component developer.
Developing device as described in section. (6) The developing device according to claim 1 or 5, wherein the microcarrier has an average particle size of 15 μm or more and less than 50 μm.