JP2669962B2 - Developer - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [0001] FIELD OF THE INVENTION The present invention finds use in electrophotography.
The developer, especially the magnetic brush using charged magnetic toner.
The electrostatic latent image is developed by the method
Used in electrophotography, where the material is transferred to a material and then fixed to obtain a copy.
The developer used. [0002] 2. Description of the Related Art Electrophotography is the process of forming a photoconductive surface on a photoconductor.
An electrostatic latent image is formed, and this electrostatic latent image is developed to form a toner image.
Either obtain this toner image directly or fix the toner image.
A copy is obtained by fixing after transfer onto a transfer member.
When developing an electrostatic latent image, the magnetic brush developing method is usually used.
Have been. As a developer used in magnetic brush development
Between conventional non-magnetic toner and carrier such as iron powder
A two-component developer which is a mixed powder is used. this
The magnetic brush development method using a two-component developer is a carrier.
And toner are mixed in a prescribed ratio and both are triboelectrically charged.
Therefore, the toner is charged to the specified polarity and only the toner is electrostatically charged.
Since it is attached to the latent image carrier surface, it is easy to transfer
There are advantages. However, the toner and carrier can be rubbed well
It requires a mixing means for charging,
Toner is consumed only to maintain a uniform toner concentration.
Toner concentration monitoring device, so-called toner control device
Since it is necessary, the developing device becomes large and the structure is complicated.
Become. If you use it for a certain period of time, the carrier will get tired
Therefore, there is a problem that the carrier needs to be replaced.
ing. Therefore, in recent years, magnetic powder and resin have been used as developers.
One-component non-charged magnetic toner, which is the main component, is used
It became so. As a developing method using this magnetic toner
The method described in Japanese Patent Publication No. 56-2705 is known.
You. This developing method uses a magnetic toner of 100 V DC / cm
The electric resistance when a field is applied is 10^Four~Ten¹¹Conduction of about Ω ・ cm
The magnetic toner carrier is made conductive by using electro-magnetic toner.
The electrostatic latent image carrier and the conductive sleeve.
Electrostatically latent image is formed through the electrically conductive magnetic toner layer, which is electrically bonded.
Forming a conductive path between the body surface and the conductive sleeve, thus
Static induced in the conductive sleeve by the electrostatic latent image charge.
The electric charge of the opposite polarity to the latent image is collected at the tip of the toner brush,
Occurring between the charge at the tip of the nerbrush and the charge at the electrostatic latent image
Permanent magnetism with Coulomb force inside the conductive sleeve
Set to overcome the magnetic attraction generated by the stone roll
The conductive sleeve and electrostatic latent image carrier
By moving it to selectively attach toner to the electrostatic latent image surface.
is there. This development method fixes the toner and obtains a direct copy
It can be applied to the so-called CPC method. But originally desired
The method used is not the CPC method for direct recording described above,
Indirect recording, that is, for repeating the photoconductor that is the master
After developing the photoconductor, use the developed toner image for general purpose
The so-called P method that can transfer to plain paper with low electrical resistance
The PC method. The developing method described above is applied to this PPC method.
And the toner has a low electric resistance, so the development is performed well.
However, due to toner scattering and transfer electric field leakage during the transfer process,
However, there is a problem that the transferred image becomes unclear.
Cheating. As described above, the magnetic toner is not suitable for the PPC method.
won. In order to overcome these difficulties of transfer, magnetic
Insulated magnetic toner with high electric resistance is used.
A method of imaging and then transferring has been proposed. Such person
According to the method, when the electric resistance of magnetic toner increases, it is generally developed.
Since it deteriorates the property, it is necessary to devise to improve the developing efficiency of toner.
Becomes As a device for this, for example, JP-A-53-12
As described in Japanese Patent No. 9639, rotate the sleeve of the developing machine.
Limit the speed difference between the sleeve and the photoconductor to the specified range
Therefore, there is a method of improving the development efficiency. In addition,
In the method described in 53-31136, the sleeve rotation
By improving the transfer method and increasing the toner movement speed,
Intended to improve the developability of insulating magnetic toner
You. That is, electricity when an electric field of 10,000 V / cm DC is applied
Resistance is 10¹²Use an insulating magnetic toner of Ω ・ cm or more to
Conductive particles on the surface of the
And attach it to the sleeve and / or magnet
The toner is brought into electrical contact with the electrodes by the high-speed rotation of the tool.
Electrified and conveyed to the latent image surface at a high speed of 10 cm / sec or more,
It is a method of developing. However, when developing with this method
If the toner comes into contact with and separates from the latent image surface at high speed,
The toner charged by is attached to the latent image surface by Coulomb force
However, since the cleaning effect of the magnetic brush becomes stronger,
Are collected from the latent image surface, which lowers the development efficiency.
Lowering development is likely to occur. Also, in this method,
If the toner is conveyed by rotating only the leave, the doctor
It becomes difficult to uniformly control the toner of the
Lumps of dust, dust,
It is easy to cause a line of insufficient development due to lack of toner. Therefore, in order to eliminate these drawbacks,
JP-A-57-12148 and JP-A-55-126266
According to the report, the toner transport speed should be 10 cm / sec or less, and
Rotate both sleeve and magnet roll in the same direction
The law was proposed. This way, the toner on the sleeve
Transfer problems at the electrode are eliminated, and the charging efficiency by the electrode is also improved.
However, the insulating non-charged magnetic toner PP, which has been considered difficult in the past,
Applicable to C method, PP of uncharged magnetic toner
The C method has come to practical use. However, non-insulating
With charged magnetic toner, the development method described above
Generally, toner is difficult to be charged, and toner is needed for development.
In order to obtain the electric charge, the surface potential of the photoconductor should be several hundreds higher than usual.
It is necessary to set it higher than V. Meanwhile, the surface potential of the photoconductor
If lower, use a zinc oxide photoconductor with a short life.
Must. Therefore, in any case, the life of the photoconductor
And the running cost of copying increases. Therefore, a charge control agent is added to the magnetic toner.
Charge the toner in advance to a positive or negative polarity.
Charged magnetic toners for use have been proposed. This is for example
Kai 57-45555, JP-A-57-45556, JP-A-57-45
As described in Japanese Patent No. 557, a magnetic toner containing resin and magnetic powder.
-Electron attracting or electron donating inside and / or outside
Add a strong substance (charge control agent) to improve the toner
This is a method of initially charging and developing. In addition, in the above publication
The proper content of magnetic powder is 30 ~ 70wt%,
The amount of control agent added is 1 to 10 times when added inside the toner.
%, 0.1 to 10% by weight when added to the outside of toner particles
% Is stated to be effective. Addition of such charge control agent to magnetic toner
Then, toner or toner and sleeve or toner
The toner is charged by frictional charging between the doctor and the doctor,
Since it has the same amount of charge as toner,
Develop the photoconductor under the conditions of the surface potential of the photoconductor as well as the developer
I can do it now. However, with charged magnetic toner,
Toner charge frictional charge
Properties are also increased, and toner is prone to electrostatic charge aggregation on the sleeve.
And the toner that has clumped on the toner control plate (doctor plate)
Accumulation of toner on the sleeve causes insufficient development due to lack of toner.
However, there is a problem that it cannot be put to practical use as an image. The object of the present invention is to overcome the above-mentioned drawbacks of the prior art.
Eliminate and use charged magnetic toner with good developability
In this case, prevent toner electrostatic charge aggregation (blocking).
Achieves practically satisfactory copies by obtaining favorable developability and transferability
Is to provide a developer that can be used. The present invention is a charged type magnetic magnet having an insulating property.
Electrostatic latent image with toner (insulating triboelectrification type magnetic toner)
When you do this, add trivalent iron oxide and other gold to the magnetic toner.
Semi-conductive ferrite carrier that is a sintered body with a group oxide
When a relatively small amount is mixed, the mechanical force of the carrier
To loosen the lumps of toner and improve the fluidity of the toner.
Can prevent electrostatic charge aggregation of the toner and eliminate streaks of insufficient development.
It was reached as a result of finding out. The developer of the present invention contains trivalent iron oxide and other iron oxides.
A sintered body with a metal oxide having an average particle size of 10 μm or less
Above, a semiconductive material having a saturation magnetization of 20 to 90 emu / g.
5 to 60 parts by weight of ferrite carrier
And contains a resin and magnetic powder, and
Triboelectric charging type insulating magnetic toner 40 to which powder is externally added
A mixture of more than 95 parts by weight or more.
You. In the present invention, a triboelectric charging type insulating magnetic toner is used.
Since the ferrite carrier to be mixed is semi-conductive,
The bias voltage leaks in the development area during the transfer phenomenon.
It is possible to apply a high bias voltage to the sleeve without
Therefore, high quality reversal development can be obtained. Hereinafter, the present invention will be described in detail. In the present invention, the ferrite carrier is
Physically, a perfect mixture of a suitable metal oxide and iron oxide
Crystallographically, spinel, perovskite,
Magnet with hexagonal, garnet, orthoferrite structure
Characterized as a functional material. That is, nickel, zinc,
Manganese, magnesium, copper, lithium, barium, bar
Oxides such as Nadium, Chromium, Calcium, etc. and trivalent ferric acid
It is a sintered body with a compound. Such a ferrite carrier has a conventional structure.
Chemically stable compared to iron powder carrier used by oxidizing the surface
There is no problem of rust and there is little resistance change during use. Also,
Small remanence, good fluidity and agitation. Ma
In addition, specific gravity is about 2/3 compared to iron powder carrier,
Therefore, it has advantages such as small torque during transportation,
The life of the rear itself is long, and the mechanical force applied to the toner is also necessary.
Not too big. Such a semi-conductive ferrite carrier
Is added to a charged magnetic toner to obtain the magnetic properties shown in FIG.
The present invention can be directly applied to the toner developing method. In FIG. 1, a non-magnetic material is provided facing the photoconductor 1.
A body cylinder (sleeve) 3 is provided.
Permanent magnet 2 having a plurality of symmetrical magnetic poles extending in the same direction
Is provided. 4 in the figure is a magnetic
The toner 5 is a toner regulating plate (doctor blade).
The developing conditions of the developing machine shown in FIG.
Type, electrical characteristics of toner 4, magnetic characteristics, photoconductor 1 and three
Distance between the sleeve 3 (development gap), sleeve 3 and toner
Distance between control plate 5 (doctor gap), sleeve 3 rotation
Rotation direction and rotation speed, magnetic force of the roll of magnet 2 and rotation direction
Direction and number of rotations can be raised, and by optimizing these, the development method
Is determined. With a normal charged magnetic toner, the developing gear
Table, doctor gap, and magnetic force of the magnet roll.
However, the appropriate range is generally limited, and
And doctor gap range from 0.1 to 0.6 mm,
The magnetic force of Gunnet roll is generally in the range of 600 to 1200 gauss
It is a target. Considering the above conditions, it can be applied to
As a result of examining the physical properties of the ferrite carrier that can be saturated,
Magnetization is 20-90 emu / g, Curie temperature is 100 ℃ or more, direct
The volume resistivity at a flow of 100 V / cm is 10^Three~Ten¹³Ω ・ c
m, an average particle diameter of 10-70 μm
Most preferred is carrier. The saturation magnetization of the ferrite carrier is 20 emu /
If it is smaller than g, the carrier may be on the sleeve during transportation.
So that it does not come off and adhere to the surface of the photoconductor.
In addition, it is necessary to increase the magnetic force of the magnet roll.
In addition, the saturation magnetization of the ferrite carrier is 90 emu / g
If it is also large, the magnetic force of the carrier increases the transportability,
The mechanical force on the toner increases. Further, the developing gap and the doctor gap
Is 1 / for magnetic toner compared to conventional two-component developer
It is better to set it as narrow as about 10. Therefore, the carrier particles
The diameter is also reduced accordingly. Too small carrier
When used, the carrier is likely to be aggregated by the toner.
In addition, the problem of carrier scattering during transport also occurs. This
Carriers with an average particle size in the range of 10 to 70 μm
A is most suitable. The shape of the carrier is almost spherical.
Is desirable. This is because the fluidity and transportability of the carrier
In addition, do not apply more destructive force to the toner to increase
It is important to be. In a general magnetic toner developing device, a doctor
-The blade or sleeve is made of a conductor, and the magnetic toner
Excess charge accumulated inLet goDeveloping with electrical means
To stabilize. Add a ferrite carrier to this development system.
If added, the doctor blade is
Or carry it so that the electrode effect of the sleeve does not deteriorate.
(A) It is necessary to lower the electric resistance before use. in this case,
Carrier volume resistivity of 10³-10¹³Ω · cm
If it is controlled to the range, the electrode effect by the carrier
It appears that the development can be further stabilized. In the present invention, the carrier is mainly toner.
It is used for the purpose of preventing charge aggregation. However, normal 2
As is clear from the examples of component developers, the carrier
Since it has a function of charging the toner,
When mixed with charged magnetic toner,
It is thought that it will be charged to some extent by friction with the carrier.
You. In the present invention, the magnetic toner is generally a carrier.
Is transported to the development area together with the amount of transport.
Considered to depend on the amount of carriers retained on the probe.
You. Therefore, by adjusting the amount of this carrier,
It seems that the mixing ratio of both can be kept within the specified range
It is. The magnetic toner of the present invention has good
Insulation to obtain good transferability and developability
Electricity that can be frictionally charged by contact with the sleeve etc.
It is necessary to have a specific property. For this, DC 4
10 when an electric field of 000 V / cm is applied.¹⁴Ω · cm
With volume resistivity exceeding 100kHz and frequency of 100kHz
It is desirable to have a relative dielectric constant of less than 3.0 in
No. Also contains resin and magnetic powderMagnetic toner has an internal charge
It contains a control agent and is loose as a fluidity modifier to the outside.
The composition is such that the aqueous silica fine powder is attached. Such a magnetic toner is as described above.
Using materials, known methods such asCrushing methodMade by
Can be achieved. That is, resin and magnetic powder, or
Raw materials such as charge control agents are charged into the mixer and premixed,
Further, it is heated and kneaded in a kneader, then cooled and solidified and then crushed.
And thenClassificationIt is obtained by doing. As the toner material, an ordinary magnetic toner can be used.
The various materials used are used. Examples of resin
For example, styrene resin, polyester resin, epoxy resin
Etc. are used, and the magnetic powder is magnetite ferrite.
Ferromagnetic materials such as iron, cobalt and nickel
The metals or alloys shown or compounds containing these elements
Etc. can be used. As an electrical control agent, for example
Use of nicrosin dyes or metal-containing azo dyes
Can be. The composition of the magnetic toner is the same as the electrical characteristics described above.
What is necessary is just to determine so that sex may be satisfied. Next, such an insulating charge type magnetic toner
Then, reverse the sleeve and magnet roll as the developing method.
The magnetic toner on the photoconductor in the developing section.
The best way is to move in the same direction at a relatively high speed and develop.
I knew it. In the charged magnetic toner of the present invention,
It has a large amount of charge and is easy to wear on the photoconductor.
Therefore, the present invention has high cleaning efficiency at the same time as development.
It is better to apply to the above method. Optimal transportation of such charged magnetic toner
The method was obtained by the following experimental results. First, the optimum toner conveyance for the charged magnetic toner
The method was examined. In FIG. 2, the inner diameter is 29.3 mm and the outer diameter is 31.4 mm.
Magnetic flux density on the mm sleeve is 1000 gauss, magnetization width is 255
8 mm symmetric magnetic pole magnet 2 and stainless steel
The number of rotations of the conductive sleeve 3 made of a non-magnetic material
 It was set within the range of 100 to 1500 rpm and 10 to 500 rpm.
The distance between the photoconductor 1 and the sleeve 3 in the developing section (developing
Sleeve 3 with doctor blade 5
A gap (docking) that regulates the amount of the magnetic toner 4 conveyed above
Ter gap) to 0.2-0.6 mm and 0.15-0.
The range was 6 mm. When applying an electric field of 4000V / cm in diameter
The volume resistivity is 5 × 10¹⁴Ω ・ cm, frequency 100kHz
Using a negatively charged magnetic toner with a relative dielectric constant of 2.1,
The surface of the Se drum is an Se drum with an outer diameter of 120 mm.
The potential is + 700V and the back side of the conductive sleeve and Se drum
And are grounded, and the Se drum is moved at a peripheral speed of 120 mm / sec.
I did an experiment. Negatively charged magnetic toner used in experiments
Is a styrene-butyl methacrylate copolymer (Sanyo Kasei
SBM600, weight average molecular weight about 90,000) 47 weight resin
%, And 50% by weight of magnetic powder (EPT-500 manufactured by Toda Kogyo Co., Ltd.)
And negative charge control agent (Bontro manufactured by Orient Chemical Co., Ltd.)
E-81) 3% by weight added toner with an average particle size of 15 μm
In addition, the hydrophobic particle size is about 200Å (angstrom).
0.3% of Rica (Aerosil R972 manufactured by Nippon Aerosil Co., Ltd.)
The toner was externally added and mixed by weight. In the above experiment, the toner conveyance direction was
Considered in, 10 types of development method (this is all)
Can be considered. Table 1 shows the experimental results of the transportation method. [0031]                                   Table 1                           Magnet rotation direction Clockwise Stop Counterclockwise   Toner movement direction Clock Counter clock Clock Counter clock Clock Counter clock                     Direction direction direction direction direction direction direction Sleeve rotation direction   Clockwise △ × △ − ◎ −   Stop-----   Counterclockwise − × − × △ × (Note) ◎: good developability Δ: Slightly poor developability, poor halftone reproducibility ×: Inferior developability, large fog density From the above experiment, the following can be confirmed.
Was. First, if the sleeve alone is rotated,
Toner tends to collect in the developing section, but
The orientation is the same as that of the photoconductor. Next, rotate the magnet alone
If the toner moves in the same direction as the photoconductor,
A good image is obtained, but uneven development occurs at low speed rotation,
Even at high speed rotation, the developability is poor and the density is difficult to obtain.
It was very difficult to adjust the pump. Then, rotate both the magnet and the sleeve.
When rotating, rotate the magnet and sleeve in opposite directions.
And the direction of toner transport in the developing unit
The best image is obtained when the same direction as the moving direction of
Was. That is, no fogging occurs in both rotations.
The toner is not in contact with the photosensitive member in the conveying direction.
Toner development and cleaning due to rolling motion in the same direction
A well-balanced image with high sharpness was obtained. In this experiment, the present inventors
Gnet roll and sleeve rotation direction
The number of revolutions was also examined, and the number of revolutions of the magnet roll was 7
High image quality at 00 rpm or higher and sleeve rotation speed of 200 rpm or higher
It was found that an image of In this case, the toner
The moving speed is measured by the method described in JP-A-55-126266.
The total is about 40 cm / sec or more, and the toner is relatively fast.
Can be transported. Also, the magnetic force of the magnet roll
Is suitable in the range of 800 to 1200 gauss.
And doctor gap are in the range represented by the following general formula
Turned out to be good. 1/2 G ≤ Dg ≤ G-0.05 (1) 0.3 ≦ G ≦ 0.6 (2) However, G: Development gap (mm) Dg: Doctor gap (mm) By the above developing method, an insulative negative charge type magnet is used.
The developing toner was successfully developed. But as mentioned above
As described above, the charged magnetic toner has a triboelectric chargeability of the toner.
In the above case, the toner is prone to electrostatic aggregation due to its strength.
Toner clumped on the sleeve accumulates on the doctor part and onto the sleeve.
Insufficient toner causes streaks of insufficient development, causing defects in the image.
I found it to be misleading. Therefore, the present invention is carried out to develop
We decided to eliminate the shortage. In this case, for the purpose of eliminating the line of insufficient development.
When the developing gap is 0.7 mm, the developing electric field becomes small,
The nature becomes small. As a result, the image density decreases.
You. Further, since the edge effect becomes stronger, the toner is
Unnecessarily adheres to the thin line of the character. In FIG. 2, the outer diameter is 31.4 mm and the surface magnetic flux density is
Saturated magnetism on a sleeve with a degree of 1000 gauss and a magnetizing width of 255 mm.
Of 50 emu / g, Curie temperature of 425 ℃, DC 100V /
Volume resistivity at 10 cm^ThreeΩ · cm, average particle diameter
40μm Ba-Zn-Ni based spherical ferrite carrier (Japan
Vertical Metal Co., Ltd. KBN-100) is attached in the range of 0.5 to 15g.
After covering the sleeve surface with a ferrite carrier,
The photoconductor was developed by adding 10 g of magnetic toner. Carry
The weight ratio of the magnetic toner to the magnetic toner is 5/95 to 60/40. this
The development gap is 0.45mm and the doctor gap is 0.35mm.
Set sleeve to clockwise 300 rpm, magnet
Rotate the roll counterclockwise at a speed of 1000 rpm to
The carrier and ferrite carrier are conveyed clockwise to
Developed with neutral toner. Depending on the amount of ferrite carrier added
FIG. 3 shows changes in the amount of magnetic toner attached to the photoconductor. From FIG. 3, the amount of ferrite carrier added is
Nevertheless, it was confirmed that the amount of magnetic toner adhered was almost constant.
Call In addition, a ferrite carrier was added in advance.
This prevents electrostatic aggregation of the magnetic toner,
Even the streaks of insufficient development due to lack of toner on
It was found that a high-quality image with high property can be obtained. the above
According to the experiment, the amount of ferrite carrier added was several grams
It turned out to be effective in some degree. Also, use magnetic toner
Even if a large amount is added, it is possible to add a small amount of ferrite carrier.
It can prevent electrostatic charge aggregation and change the image quality even when continuous copying is performed.
It was confirmed that a long-life developer with less deterioration was obtained.
It should be noted that in the above experiment, the toner formed on the Se drum was
The toner image is transferred to the transfer paper by corona discharge, and
Troll fixing was performed to obtain a copy image. At this time,
The paper has high electrical insulation, so there is no restriction on transfer paper,
General-purpose plain paper with low resistance could be used. Above
Depending on the solid copy conditions, good developability and transferability
Consecutive good copy images with sufficient image density without fog
I was able to get. In the above, a typical transfer type copying machine is mainly used.
Although the electrophotographic method was explained in the above, the transfer method is not limited to this.
Printer, facsimile, etc.
Develop an electrostatic latent image such as an edge or photoreceptor, then transfer it
Needless to say, it can be applied to various recording devices that perform copy recording.
not. Furthermore, in the present invention, the toner conveying means
Then, the cylindrical non-magnetic sleeve and this non-magnetic sleeve
When using a permanent magnet roll rotatably arranged inside
However, as a magnetic field generating means,
Electromagnets other than the same may be used, or both may be used in combination.
You. In addition, the belt-shaped non-magnetic carrier and NS in the same direction
In combination with the magnetic field generating means in which the alternating magnetic field moves
However, it goes without saying that the same effect can be obtained. In the present invention, the magnetism of the ferrite carrier is
Air characteristics were measured using a vibrating sample magnetometer (VSM-3 manufactured by Toei Industry Co., Ltd.)
(Type). Also ferrite carrier and
For volume resistivity of magnetic toner, use a small sample
(10 mg carrier, 10 mg toner) Weigh out and dial
3.05mmφ with improved gauge (cross-sectional area = 0.073cm^Two)
Insert it into the insulation cylinder of the rear acetal and weigh 0.1 kg.
Measure the resistance of the carrier under an electric field of DC 100V / cm under load
And the toner resistance is measured with an electric field of DC 4000V / cm
Then, each volume specific resistance was calculated. Yokogawa for measurement
-4329A insulation resistance tester manufactured by Hewlett-Packard Co., Ltd.
Was used. On the other hand, for the relative dielectric constant of toner, use a Q meter.
Using a cylindrical cell with an inner diameter of 42 mm
The bottom surface of the module is covered with a conductor to serve as an electrode. The sides of the cell are thick
Cover with 3 mm, 5 mm high polyacetal insulator. this
Weigh 3-5g of magnetic toner on the two
The toner ratio at a frequency of 100 kHz is sandwiched between the opposed disk electrodes.
The dielectric constant was measured. Q meter is Yokogawa Electric Co., Ltd. QM
-102A type was used. [0042] EXAMPLES Hereinafter, the present invention and reference examples will be further described by examples.
As described below, the contents of the present invention are limited by these.
Not. [0043]Example 1 Using a Se drum with an outer diameter of 120 mm as the photoconductor,
60 emu / g, Curie temperature 425 ℃, DC 100V / cm
Volume resistivity is 10⁹Ωcm, average particle diameter 40μ
m spherical ferrite carrier (Ba from Hitachi Metals, Ltd.)
-Zn-Ni ferrite carrier KBN-100) and DC 4000
Volume resistivity at V / cm is 5 × 10¹⁴Ω ・ cm, frequency
Negatively charged magnetic toner with a relative permittivity of 2.3 at 100 kHz
Using the developing device shown in FIG.
Static with a surface potential of +650 V created by reflection exposure
The latent image was developed. The negatively charged magnetic toner used is
Tylene-butadiene copolymer (Pryor manufactured by Goodyear)
Light S-5B) 48% by weight and magnetic powder (EP manufactured by Toda Kogyo Co., Ltd.)
T-500) 50% by weight of negative charge control agent (Orient Chemical
Bondron E-81 manufactured by Co., Ltd.) Average particle size with 2% by weight added
18μm toner, hydrophobic silica fine powder (Aero Japan
Lusil Co., Ltd. Aerosil R972) 0.3% by weight externally added and mixed
It is a toner. The peripheral speed of the Se drum is 150 mm / sec.
Yes, with a developing device made of stainless steel with an outer diameter of 32 mm
On the sleeve surface by rotating the sleeve at 300 rpm
It has a magnetic force of 1000 gauss and a magnetizing width of 255.
10 mm magnet roll with 8 symmetric magnetic poles
Rotate at 00 rpm to develop gap and doctor
-Set the gap to 0.4mm and 0.2mm respectively.
Specified. The rotation direction of the sleeve and magnet roll is
In the developing section, the sleeve is magnetized in the opposite direction to the Se drum.
The troll is in the same direction as the Se drum. Sleeve and S
e Ground the rear surface of the drum and measure 7g of ferrite carrier.
After attaching to the pick-up sleeve, magnetic toner10 gTogether with
To develop the electrostatic latent image on the Se drum. Obtained after development
The toner image formed is transferred to plain paper by corona discharge.
Heat roll fixing was performed to obtain a copy image. Under the above copying conditions, the magnetic toner
Good image development and transfer, and fogging-free image density
A sufficiently good copy image was obtained. [0046]Example 2 Se-Te with an outer diameter of 120 mm that is sensitive to long wavelengths as a photoreceptor
The volume resistivity at 4000V / cm is 10 using the system drum.
^FifteenPositive load with a relative dielectric constant of 2.1 at Ωcm and frequency of 100kHz
The same blow as in Example 1 was performed using electro-magnetic toner.
Semiconductor laser (Hitachi
HL-1400 manufactured by Seisakusho Co., Ltd., oscillation wavelength 780nm, output 5mW)
With a surface potential of 700V created by the divided exposure of
The latent image was reverse developed. Positively charged magnetic toner used
Is a styrene-butyl methacrylate copolymer (Sanyo Kasei
47% by weight of SBM700 manufactured by Co., Ltd. and magnetic powder (Toda Kogyo Co., Ltd.)
KN-320 manufactured by KN-320), positive charge control agent (orientated)
Average particle with 3% by weight of Gakugaku Co., Ltd. Bontron N-01 added
15μm diameter toner, hydrophobic silica fine powder (Aero Japan
Externally add 0.3% by weight of Zil's Aerosil R972) and mix.
It is the combined toner. The peripheral speed of the Se-Te drum is 100 mm / sec.
In the developing device, the sleeve and the back of the Se-Te system drum are
A bias voltage of +650 V is impressed on the sleeve side between the surfaces.
In addition, an inversion phenomenon was performed in exactly the same manner as in Example 1.
The toner image formed on the Se-Te drum in this way is
Transfer to plain paper by corona discharge, then heat roll
After fixing, both developability and transferability were good.
Good print image with sufficient density without fog
Was. [0048]Example 3 As a photoreceptor, it has sensitivity in the visible range (400 to 650 nm) to long wavelengths.
Two-layer organic photoconductor drum with an outer diameter of 120 mm (charge generation
Layer: metal-free phthalocyanine pigment, charge transport layer: oxazo
Example 2
Using a ferrite carrier and a positively charged magnetic toner,
Using the same developing device as in Example 1, reflection of the visible light source
Electrostatic latent having a surface potential of -650V created by exposure
The image was developed. The peripheral speed of the organic photosensitive drum is 150 mm / sec.
Yes, the sleeve and magnet roll are as in Example 1.
The same one is used, and the rotation direction and the rotation are the same as in the first embodiment.
Rotation at the rotation speed to
The tops were set to 0.45 mm and 0.35 mm, respectively. In this manner, the photosensitive drum formed on the organic photosensitive drum is formed.
The transferred toner image is transferred to plain paper by corona discharge, and
After heat roll fixing,
Good copyability with good transferability and sufficient fog-free density
-I got an image. [0051]Example 4 The same organic photoconductor drum as in Example 3 was used as the photoconductor.
The ferrite carrier of Example 1 and the negatively-charged magnetic toner
And using the same developing device as in Example 2,
-700V surface created by split exposure of semiconductor laser
The electrostatic latent image having an electric potential was reversely developed. The peripheral speed of the organic photosensitive drum is 100 mm / sec.
Yes, sleeve and organic photoconductor drum in developing device
Between the back side of the negative side of the sleeve and negative bias voltage of -650V.
A pressure is applied, and reversal development is performed in the same manner as in Example 3.
Was. In this way, the toner particles formed on the organic photoconductor drum are
The toner image is transferred to plain paper by corona discharge, and then
After roll fixing, developability and transferability
Good print quality with good fog and sufficient density without fog
An image was obtained. [0053]Example 5 Mylar coated on CdS with outer diameter 160mm as photoreceptor
The ferrite carrier of Example 1 and the negative charge were used.
Developing device using magnetic toner of the same type as in Example 1
+ 600V created by reflection exposure of visible light source using
An electrostatic latent image having a surface potential of was developed. Peripheral speed of photoconductor
Is 86 mm / sec.
Rotate at rpm to generate 800 gauss of magnetic force on the sleeve surface.
1300rpm magnet roll with 8 symmetric magnetic poles
To rotate the development gap and doctor gap.
It was set to 0.3 mm and 0.15 mm, respectively. In addition, the photoconductor
The rotation direction of the magnet and the magnet roll is the same as in the first embodiment.
It is like. The toner image thus formed on the photoreceptor
Is transferred to plain paper by corona discharge,
Image transfer, it has excellent developability and transferability.
A good copy image with no fog and sufficient density was obtained.
Was. [0054]Example 6 Conducted using ZnO master paper with outer diameter 210mm as photoreceptor
Using ferrite carrier of Example 2 and positively charged magnetic toner
And using the same developing device as in Example 1,
Has a surface potential of -450 V created by reflection exposure of the source
Electrostatic latent image was developed. The peripheral speed of the photoconductor is 65 mm / sec.
And the same sleeve as in Example 1 was rotated at 350 rpm,
Eight symmetrical poles with a magnetic force of 1200 gauss on the sleeve surface
Is rotated at 1400 rpm, and the current
Image gap and doctor gap are 0.5m each
It was set to m and 0.3 mm. The photoconductor, sleeve and
The rotation direction of the magnet roll is the same as in the first embodiment. The toner thus formed on the photoreceptor
The image is transferred to plain paper by corona discharge,
Image transfer, it has excellent developability and transferability.
The density is good without fog and good copy images can be obtained.
Was. [0056]Reference example Ferrite carrier with a particle size of 74-149 μm (Hitachi Metals
KBN-100 manufactured by K.K.) and two resin binders manufactured as follows:
A dressing carrier was prepared. Styrene-butyl methacrylate copolymer
30 parts by weight (SBM700 manufactured by Sanyo Kasei Co., Ltd.) and magnetic powder (Toda
70 parts by weight of EPT500 manufactured by Kogyo Co., Ltd. is dry-mixed and cooled and solidified.
After crushing, pulverizing and classifying carrier (A) with a particle size of 74-149 μm
I got The same as above except that the dispersion conditions are changed.
Resin-bonded carrier (B) with a particle size of 74-250 μm under
I got These carriers and the ferries used in the present invention
Figure 4 shows the measurement results of volume resistivity of carrier (C).
You. The magnetic toner is a styrene-methacrylic acid block.
Chill copolymer (SBM700 manufactured by Sanyo Kasei Co., Ltd.) 46 parts by weight, po
Double propylene (Viscol 500P manufactured by Sanyo Chemical Co., Ltd.)
Parts, magnetic powder (EPT500 manufactured by Toda Kogyo Co., Ltd.) 50 parts by weight, negative
Charge control agent (Bontron E-8 manufactured by Orient Chemical Co., Ltd.)
1) Dry mixing with 2 parts by weight, kneading with heat in a kneader,
After cooling and solidifying, pulverize and classify to obtain a toner with an average particle size of 10 μm.
Prepared and added to it a fine powder of hydrophobic silica (Japan Aerosil
0.3 parts by weight of Aerosil R972 manufactured by
Manufactured. Each of the above carriers and the above magnetic toner are
Used organic photoconductor drum (Except for 50mm outer diameter)
The same electrostatic latent image as in Example 3) was reverse developed. Photoconductor drive
The peripheral speed of the system is 100 mm / sec, and the surface potential of the electrostatic latent image is
It was −500V and the residual potential was −50V. 24 OD for development
mm aluminum alloy sleeve and flux tightness on the sleeve
Equipped with a magnet roll with a degree of 600 G and 10-pole symmetric magnetization
Using a developing device having a structure similar to that shown in FIG.
Was. In this developing device, the sleeve is set counterclockwise.
Rotate at 90 rpm in the direction
Rotate in the opposite direction at 1300 rpm to
Set the actor gap to 0.35mm and 0.30mm,
Insert the sleeve side between the sleeve and the backside of the photosensitive drum.
A bias voltage of -300 V was applied to the. Also, the development area
The mixing ratio of the toner was 50 to 70% by weight. Thus formed on the photosensitive drum
The toner image is transferred to plain paper by corona discharge.
Heat roll fixing was performed to obtain a copy image. Obtained
Table 2 shows the evaluation results of each image. [0063]                                   Table 2No. Use carrier Image density Image unevenness resolution Fog Comprehensive evaluation 1 None 0.94 △ △ ○ × 2 Carrier A 1.08 ○ ○ ○ △ 3 Carrier B 1.00 × × ○ × 4 Carrier C 1.30 ○ ○ ○ ○ (Note) ○: Excellent Δ: Substantially good ×: poor From the above table, the magnetic toner and the resin binding type key
And No. 2 and 3 when used in combination
However, in the case of the present invention (No. 4), the image density becomes high.
I understand. In particular, use a ferrite carrier (No. 4)
By doing so, the highest quality image can be obtained. Also image
The ferrite carrier was used even after comprehensively evaluating
It turns out that the best quality image is obtained in this case. An image due to such a difference in material of the carrier
The difference in quality is considered to be due to the following reasons. Figure
As shown in Fig. 4, the ferrite carrier is a resin-bonded key.
Since the resistance value is lower than that of the carrier, the electrode effect is large.
The ferrite carrier has soft ferrite
Charge is accumulated in the carrier after development.
No (Even if the charge temporarily accumulates, it is released immediately)
On the other hand, in the resin-bonded carrier, magnetic powder is dispersed in the resin.
Since it consists of fine particles, it is easy for electric charges to accumulate in the resin part.
You. Furthermore, the resin-bonded carrier easily adheres to the surface of the photoconductor.
This is because of the nature of [0067] According to the present invention, the load which has been insufficient conventionally
The fluidity of electro-magnetic toner is greatly improved, and the toner is charged.
Since aggregation can be prevented, normal or
Can be expected to greatly improve the image quality of the reversal development system.
Various copiers, printers and fax machines that apply child photography technology
It is possible to achieve miniaturization such as millimeter and high performance.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic cross-sectional view showing an example of a magnetic toner developing device. FIG. 2 is a cross-sectional view of a main part of a developing device for describing a developing method using the developer of the present invention. FIG. 3 is a graph showing the relationship between the amount of ferrite carrier added and the amount of magnetic toner adhering to a photoreceptor. FIG. 4 is a graph showing the relationship between the volume resistivity of various carriers and the measurement electric field. [Explanation of reference numerals] 1 ... photoreceptor 2 ... magnet 3 ... sleeve 4 ... magnetic toner 5 ... toner regulation plate (doctor blade)

Continuation of front page    (72) Inventor Koji Noguchi               Hitachi Metals, 5200, Sankajiri, Kumagaya City, Saitama Prefecture               Kumagaya factory (72) Inventor Tsutomu Iimura               Hitachi Metals, 5200, Sankajiri, Kumagaya City, Saitama Prefecture               Magnetic Materials Research Institute Co., Ltd.                (56) References JP-A-59-162563 (JP, A)                 JP-A-52-56536 (JP, A)                 JP-A-58-23032 (JP, A)

Claims (1)

(57) [Claims] A sintered body of a trivalent iron oxide and another metal oxide having an average particle size of 10 µm or more and a saturation magnetization of 20 to 90.
containing a semiconductive ferrite carrier 5 parts by weight to less than 60 parts by weight is emu / g, a resin and a magnetic powder
A developer characterized by being mixed with more than 40 parts by weight or more than 95 parts by weight of triboelectrification type insulating magnetic toner to which hydrophobic silica fine powder is externally added . 2. The developer according to claim 1, wherein the magnetic toner is used.
Developer but which is characterized by containing a charge control agent.