JPH0470890A - Magnetic brush cleaning method - Google Patents

Abstract

PURPOSE:To efficiently clean the toners remaining on the surface of a photosensitive body even if the toners are small in grain size by applying a resin coated carrier having fine pores on the surface to magnetic brush cleaning. CONSTITUTION:The resin coated carrier consists of a carrier core material 1, a resin coating layer 2 to cover the carrier core material 1 and the fine pores 3 formed on the surface thereof. The magnetic brush is then formed on the surface of a cleaning roller 12 by the magnetic force of a magnet body 13. The thickness thereof is regulated by passing a layer thickness regulating blade 15 along this brush. The magnetic brush is in succession transported on the roller 12 and rubs the surface of the photosensitive body 11. The untransferred residual toners on the surface of the photosensitive body 11 are moved to the carrier surface by the rubbing force of the magnetic brush, the triboelectrostatic charge with the carrier and an impressed bias voltage, by which the toners are cleaned. The small grain size toners are efficiently cleaned by the pores on the carrier surface.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a magnetic brush cleaning method for cleaning toner remaining on an electrostatic latent image carrier using a magnetic brush.

Prior Art and Problems Generally, in electrophotography, an electrostatic latent image is formed on the surface of an electrostatic latent image carrier such as a photoreceptor, and this is developed with toner to make it visible, and a visible image made of this toner is created. An image is formed by transferring the image onto a transfer material such as paper and fixing the transferred image. The photoreceptor is used repeatedly by cleaning the toner remaining on the surface of the photoreceptor without being transferred during the process of transferring a visible toner image onto a transfer paper. Various methods are known as this cleaning method, such as a magnetic brush cleaning method (for example, Japanese Patent Publication No. 62-45556), a blade cleaning method, a fur brush cleaning method, and a web cleaning method.

The present invention belongs to the magnetic graph/cleaning method among these cleaning methods, and the magnetic brush cleaning method is a cleaning method in which residual toner particles are moved toward the magnetic brush while sliding a magnetic brush on the surface of the photoreceptor. This cleaning method is superior in that it does not damage the photoconductor surface compared to, for example, blade cleaning, which scrapes off residual toner by pressing an elastic cleaning blade against the photoconductor surface. It wasn't satisfying. In addition, in recent years, in order to achieve high image quality, it has been considered to reduce the particle size of toner, but poor cleaning of small particle size toner has also become a problem in blade cleaning. Poor cleaning becomes a major problem as the number of products increases.

Problems to be Solved by the Invention The present invention has been made in view of the above-mentioned circumstances, and an object of the present invention is to provide a magnetic brush cleaning method that provides excellent cleaning performance even for toner of small particle size.

Means for Solving the Problems The present invention provides a method for cleaning untransferred toner remaining on an electrostatic latent image carrier using a magnetic brush, in which a carrier forming the magnetic brush has a large number of pores on its surface. The present invention relates to a magnetic brush cleaning method characterized by using a resin-coated carrier.

The present invention will be described below with reference to FIG. 4, which shows an example of an apparatus embodying an embodiment of the magnetic brush cleaning method of the present invention.

In the figure, (11) is a photoreceptor as an electrostatic latent image carrier, and for example, one having an organic photoconductive layer on the surface can be used. Although not shown in the figure, the photoreceptor (II
), a latent image forming means, a developing means using a developer, a transfer means, etc. are also arranged.

A cleaning roller (1,
2) A stirring roller (14) is arranged, and a toner collection roller (17) is arranged below the cleaning roller (12).

The cleaning roller (12) is a cylindrical body made of a conductive non-magnetic material, and faces the photoreceptor (11), which is rotationally driven in the direction of arrow (a), with a certain gear knob, and rotates clockwise (arrow C). It is possible to rotate it.

In addition, a DC bias power supply (20X bias voltage: Vb) is connected to the cleaning roller (12).
In the figure, the negative side of the bias power supply (20) is connected to the cleaning roller (12).

The magnet body (13) housed inside the cleaning roller (12) includes a plurality of magnets each having magnetic poles extending in the axial direction, and arranged so that the magnetic poles are alternately located at the outer periphery as S and N poles. direction of rotation of the photoreceptor (arrow (a))
In contrast, it can be rotated counterclockwise (arrow (b)).

Diagonally above and to the left of the cleaning roller (12) is a layer thickness regulating blade (
15) is arranged opposite to the cleaning roller (12) with a certain gap therebetween, and a cleaning blade (16) is pressed against the lower left side.

The stirring roller (14) has a cleaning blade (12
) and is arranged parallel to the back side of the main body, and can be rotated in the direction of arrow (d).

The toner collection roller (17) is made of a conductive non-magnetic material such as aluminum, and is similar to the cleaning roller (12).
) with a certain gap below the arrow (e
) can be rotated in the direction of

The toner collection roller (17) is also grounded via an AC power source (21) and a DC power source (12).
As a result, a bias voltage in which an alternating current voltage (Vms) is superimposed on a direct current voltage (VSS) is applied to the toner collection roller (17).

A cleaning blade (8) is pressed against the left side of the toner collection roller (17), and a toner transport roller (19) is arranged below the cleaning blade (18).

In the cleaning device with the above configuration, first,
The magnetic carrier is coated and supplied onto the cleaning roller (12) by rotating, stirring and conveying the stirring roller in the direction of arrow (d).

In the present invention, a resin-coated carrier having pores on its surface is used as the magnetic carrier. The carrier will be explained in detail below.

That is, as shown in FIG. 1, the resin-coated carrier of the present invention comprises a carrier core material (1), a resin coating layer (2) covering the carrier core material (1), and a resin coating layer formed on the surface of the resin coating layer. Consists of pores (3). Compared to the conventional resin-encased carrier shown in FIG. 3, the major feature is the presence of pores (3).

The pores on the surface of the resin-coated carrier of the present invention are specifically defined by its pore size distribution, average pore diameter, and total pore volume.

The diameter of each pore existing on the surface of the resin coating layer is 0.001-3μ
m, preferably 0.001 to 2 prn, more preferably 0.005 to 2 μm. Those with pore diameters smaller than o, ooiμm are tona~
It is no longer possible to expect sufficient effects from the viewpoint of crushability, etc.
If it is larger than 3 μm, the toner trapping property becomes too strong,
Fluidity and developability may be impaired.

The average pore diameter corresponds to the pore diameter distribution range mentioned above.
It is desirable that the heel is in the range of 0.1 to 0.5μ. By setting the average pore diameter within the above range, the crushability of the toner and the charging characteristics of the toner can be improved.

In the present invention, the total pore volume is expressed in two ways: total pore volume per liter of carrier (mff/g) and total pore volume per m4 of coated resin layer (m(2/m12)).

The total pore volume (+a12/g) per gram of carrier can be determined by mercury boronmetry. In the carrier of the present invention, the value is 0.001 to 0,1
mQ/g, preferably 0.01-0.051112/g
It is desirable to have a value of . The value is 0.001rn
If it is smaller than Q/9, there will be insufficient pores on the carrier surface, and there is a possibility that the effect of the pores will not be obtained. When it is larger than 0.1 m12/g, there are too many pores and the coating layer becomes brittle.

Coating resin 1n (total pore volume per liter (+++(1/+m
12) is the total pore volume (I
I (2/l?) can be determined by converting from the true specific gravity of the coating layer and the carrier core material filling rate. In the carrier of the present invention, the value is 0.1 to 2 mQ/
ri (1, preferably 05~l, 5txQ/r
It is desirable to have a value of sQ. Its value is O, l x
If it is smaller than i(1/wa(l), there will be insufficient pores on the carrier surface, and the effect of the pores may not be obtained.If it is larger than α/lnQ, there will be too many pores and the coating will be difficult. The layer becomes brittle.

Next, the constituent materials of the carrier of the present invention will be explained.

The carrier core material, which is a component of the carrier of the present invention, should have a size of at least 20 μI++ (average particle diameter) from the viewpoint of preventing carrier adhesion (scattering) to the electrostatic latent image bearing member, and should have a carrier stripe. In order to prevent deterioration of image quality, such as to prevent the occurrence of such problems, use one with a diameter of at most 100 μm.

Specific materials include those known as two-component carriers for electrophotography, such as metals such as ferrite, magnetite, iron, nickel, and cobalt, and these metals and zinc, antimony, aluminum, lead, tin, bismuth, beryllium, and manganese. , selenium, tungsten, zirconium,
Alloys or mixtures with metals such as vanadium, iron oxide,
Metal oxides such as titanium oxide and magnonium oxide, nitrides such as chromium nitride and vanadium nitride, mixtures with carbides such as silicon carbide and tungsten carbide, ferromagnetic ferrite, and mixtures thereof can be applied. .

Examples of carrier coating resins include polystyrene resins, poly(meth)acrylic resins, polyolefin resins, polyamide resins, polycarbonate resins, polyether resins, polysulfinic acid resins, polyester resins, Epoquine resins, and polybutyral resins. resin, urea resin,
Various thermoplastic resins and thermosetting resins such as urethane/urea resins, silicone resins, polyethylene resins, and Teflon resins, and mixtures thereof, as well as copolymers, block polymers, graft polymers, and Polymer blends and the like are used. Furthermore, in order to improve charging properties, resins having various polar groups may be used.

In particular, when considering the ring resistance #, coating resins with good mold releasability, such as silicone resins or polyolefin resins, are preferred. The surface of the carrier of the present invention is preferably covered with carrier coating resin by 70% or more, preferably 90% or more, more preferably 95% or more. If the coverage is less than 70%, the characteristics of the carrier core material itself (unstable environmental resistance, decreased electrical resistance, unstable charging) will be strongly visible through the background, making it impossible to take advantage of the advantages of the resin coating.

The filling rate of the carrier core material is set to about 90wt% or more, preferably 95wt% or more. The filling rate may be interpreted as indirectly regulating the resin coating layer thickness of the carrier. If the carrier core material filling rate is less than 90w%, the coating layer becomes too thick and may cause peeling of the coating layer, etc. It has poor durability and poor charging stability.

It is also possible to express the resin coating layer thickness indirectly by specific gravity. The specific gravity of the carrier of the present invention is greatly influenced by the type of carrier core material, but as long as the carrier core material is used, the specific gravity of the carrier of the present invention is 3.5 to 7.5, preferably 4.0 to 6.0, more preferably 4.0 to 6.0. It shows a value within the range of about 4.0 to 5.5. If the value is outside this range, the same disadvantages as those caused by a carrier that is not coated with an appropriate filling rate as described above will occur.

The electrical resistance of the resin-coated carrier of the present invention is
IXIO"Ω" cm, preferably 10'-10110
cm, more preferably about 10' to 10''Ω'Cm. If the electrical resistance is less than 1X10' Ωcm, carrier development occurs and the image quality deteriorates.

Furthermore, if it is larger than lXl0"Ω・cm, the toner will be charged excessively, making it impossible to obtain an appropriate image density. Electrical resistance can be considered to be an indirect expression of the resin coverage rate and carrier filling rate mentioned above. You can also do it.

Preferably, the carrier used in the present invention further provides unevenness to the resin coating layer. Figure 2 shows the resin coating layer (2
) shows an uneven form, and the pores (3) are present on the uneven surface of the resin coating layer (2). By providing such irregularities on the surface of the carrier, it is possible to obtain a carrier with improved toner cleaning performance.

Surface unevenness will be explained in more detail.

The surface unevenness structure of the surface coating layer is expressed by the following formula [I]: [where the outer periphery represents the outer periphery of the projected image of the carrier particles, and the area represents the average value of the projected area of the carrier particles.

], its value is 1
It is preferably within the range of 30-200. The S value is
It represents the degree of unevenness on the particle surface, and the greater the degree of unevenness of the surface condition, the farther away from 100 the value becomes. Shape factor 5
1 For example, image analyzer (Ruzex 500
0. (manufactured by Nippon Regulator Co., Ltd.); however, since there is generally no significant difference in the measurement of the shape factor S depending on the model, this does not mean that the measurement must be performed with the above-mentioned model.

Additionally, additives such as fine particles having a charge imparting function or conductive fine particles may be added to the carrier-coated resin layer of the present invention.

As fine particles with a charge imparting function, Cry, FeO
2, Fe50 Ire, , MnO2, MnO2, Nb
O2, PtO,, Ti0z, Ti, O,, T i 30
s, WO2, ■, 01, A1. O,,MgO,5i0
Specific examples include metal oxides such as 2, ZrO, and BeO, dyes such as nigrosine base, and spiron black TRH.

Examples of conductive fine particles include carbon black, acetylene black, carbon black, and SiC.

Carbide such as TiC, MoC, ZrC, BN, NbN.

Examples include nitrides such as TiN and ZrN, and magnetic powders such as ferrite and magnetite.

Addition of metal oxides, metal heptadides, and metal nitrides is effective in further enhancing charging properties. It is thought that by adding conductive fine particles such as carbon blank, the electrical resistance of the carrier is appropriately lowered, and charge leakage and accumulation are performed in a well-balanced manner.

The size, amount, etc. of the above-mentioned additives are determined based on the characteristics of the carrier of the present invention and the pore morphology, coverage rate, etc.
There is no particular limitation as long as the characteristics such as electrical resistance are satisfied, but in terms of the size of the fine particles, in relation to the preferred manufacturing method of the carrier of the present invention described later, for example, fine particles can be aggregated in a resin solution or dehydrated hexane. without doing,
The particle size may be as long as it can be uniformly dispersed to form a slurry.
Specifically, the volume average particle size may be about 2 to 0.001 μm, preferably about 1 to 0.01 pm.

Further, as for the amount of the internal particles added, although the amount cannot be specified in part as described above, it is Q, lvt% to 60vt%, preferably 1 vt% to the coating resin.
．． Qwt% to 40W[% is appropriate.

Next, a method for producing a resin-coated carrier having pores according to the present invention will be explained. The method for producing the carrier of the present invention is not particularly limited as long as the carrier having the above-mentioned pores can be obtained, and the following two methods are preferably used.

One of the preferred manufacturing methods is to disperse fine particle components soluble in a suitable solvent in advance in a coating resin solution, and after forming the coating layer, the fine particles are immersed in a soluble solvent to elute the soluble fine particle components. A method of forming pores on the surface of the coating layer can be mentioned. In this method, the pore size is determined by the particle size of the solvent-soluble fine particle component, the degree of dispersion, etc. Further, the coating layer can be formed by a powder capsule method, a spray dry method, or the like.

As fine particle components that can be used in this method, there may be mentioned fine particles of metal oxides such as ferrite, halides or hydroxides of alkali metals or alkaline earth metals, transition metal complexes, and the like.

It goes without saying that it is necessary to use a solvent that does not dissolve the resin at the same time.

More specifically, for example, there is a method in which ferrite is eluted by immersing a carrier having a resin coating layer containing ferrite in an acidic aqueous solution such as hydrochloric acid, thereby forming pores on the carrier surface. can do.

Furthermore, when adding the above-mentioned fine particles having a charge imparting function or conductive fine particles, it is good to add these additives and make them exist in the coating resin solution, or to form pores like ferrite etc. The use of particles that function both as electrically conductive fine particles and as conductive fine particles is advantageous from the viewpoint of the manufacturing method and properties.

Another preferred method for producing the carrier of the present invention is a surface polymerization coating method.

The surface polymerization coating method uses: ■ a highly active catalyst component that contains titanium and/or zirconium and is soluble in a hydrocarbon solvent; It can be formed by polymerizing an olefin monomer, such as ethylene, on the surface of the carrier core material. Furthermore, when fine particles having a charge imparting function or conductive fine particles are added, these additives may be added and present at the time of forming the above-mentioned coating layer. Specifically, Japanese Patent Publication No. 60-10680
The method described in Publication No. 8 is suitable.

This publication is hereby incorporated by reference as part of this specification.

When a carrier coating layer is formed by this surface polymerization coating method, in addition to being able to form a coating layer having pores on the surface of the carrier as described above, film strength and
A durable carrier with excellent adhesion between the core particles and the resin coating layer can be obtained.

When the carrier of the present invention obtained as described above is supplied onto the cleaning roller (12), it forms a magnetic body (13).
It is held on the surface of the cleaning roller (12) by the magnetic force, forms a magnetic brush, and is conveyed in the direction of arrow (c). Conveyance is carried out by rotating only the magnet (13), only the cleaning roller (12), or both, but from the standpoint of mixing and agitating the carrier, it is recommended to rotate at least the magnet (13). preferable.

The thickness of the carrier applied onto the cleaning roller (12) is regulated by passing through a certain gap formed between the layer thickness regulating blade (15) and the cleaning roller (12). The surface of the photoreceptor (11) is rubbed on the surface of the photoreceptor (11) as it is conveyed on the cleaning roller, and at this time, the untransferred residual toner on the surface of the photoreceptor (11) is mixed with the sliding force of the magnetic brush on the cleaning roller (12) and the carrier. Frictional charging and applied bias voltage (Vb
), the residual toner moves to the carrier surface and cleans the residual toner from the photoreceptor surface.

As mentioned above, in the present invention, since a resin-coated carrier having pores on the surface is used, even if the residual toner is small-sized toner, sufficient contact between the toner particles and the carrier particles can be maintained. Therefore, residual toner on the surface of the photoreceptor can be efficiently cleaned.

Furthermore, since the pores on the carrier surface are excellent in capturing toner particles, this also has an effect on toner cleaning performance.

The residual toner captured by the carrier is further conveyed together with the carrier and reaches the closest area to the toner collection roller (17), where the toner collection roller (17) selectively collects only the toner from the magnetic brush using a bias voltage Vss. Suction. Although it is possible to collect toner by applying only a DC bias voltage, in order to collect toner more effectively, it is preferable to apply an AC bias voltage (VmS) in addition to the DC bias voltage.

The toner collected by the toner collection roller (17) is rotated and transported in the direction of arrow (e), scraped off from the surface of the toner collection roller (17) by a cleaning blade (18), and then removed by the toner transport roller (19). It is discharged.

The present invention will be explained below using examples.

(+) Toner production example 1 Ingredients Parts by weight/Styrene
〇-Butyl methacrylate pine resin 100 (softening point, 1
Carbon black 8 (manufactured by Mitsubishi Chemical Corporation, MA#8)
) Dye 5 (Pontron P-51, manufactured by Orient Chemical Industry Co., Ltd.) The above materials were thoroughly mixed in a ball mill, and then kneaded on three rolls heated to 140°C. After the kneaded material was left to cool, it was coarsely ground using a feather mill and further finely ground using a jet mill.

After that, air classification was performed to obtain a volume average particle size of 11.0 μm;
Thereafter, hydrophobic silica (manufactured by Nippon Aerosil Co., Ltd., R974) was added at 3% by volume to the toner and mixed using a Henschel mixer to obtain a toner.

・Toner production example 2 The volume average particle size was 8.3μ using the same method as toner production example 1.
I got the so-called toner.

・Toner production example 3 By the same method as toner production example 1, volume average particle size 6, Op.
m toner was obtained.

Carrier Production Example 1 (1) Preparation of titanium-containing catalyst component In a 500-volume flask purged with argon, 200+ff of dehydrated n-hebutane at room temperature and 15 g of magnesium stearate, which had been previously dehydrated under reduced pressure (2IIIHg) at 120°C, were added. 25 mmol) to form a slurry.

After 0.449 (2.3 mmol) of titanium tetrachloride was added dropwise with stirring, the temperature was started to rise, and the mixture was reacted under reflux for 1 hour to obtain a viscous and transparent solution of the titanium-containing catalyst component.

(2) Activity evaluation of titanium-containing catalyst component Dehydrated hexane 400+*L triethylaluminum 0,8
mmol, 0.8 mmol of diethylaluminium chloride and 0.004 mmol of the titanium-containing catalyst component obtained in (1) above as titanium atoms were collected and introduced.
The temperature was raised to 90°C. In this case, the system internal pressure is 1.5 kg/
It was cm2G. Next, hydrogen is supplied, 5,5
After increasing the pressure to kg/cm”G, the total pressure is 9,5
Ethylene was continuously supplied so as to maintain the concentration at kg/cm"G, and polymerization was carried out for 1 hour to obtain 70 polymers. The polymerization activity was 365 kg/g・Tl-Hr,
MFR of the obtained polymer (190°C1 load!2.16
The melt flowability in Jig (JIS K7210) was 40.

(3) Reaction of titanium-containing catalyst component and filler and polymerization of ethylene Sintered ferrite powder F-20 dried in 500 m12 of dehydrated hexane at room temperature and under reduced pressure (2 mmHg) at 200°C for 3 hours in an argon-substituted autoclave with an internal volume of 1i2
0 (manufactured by Powder Chick, volume average particle diameter 70 μm) 45
0. and started stirring. Next, the temperature was raised to 40°C, and 0.02 mmol of the titanium-containing polymerization catalyst component (1) was added as titanium atoms, and the reaction was carried out for about 1 hour. Then, 2.0 mmol of triethylaluminum and 2.0 mmol of diethylaluminum chloride were added,
The temperature was raised to 90°C. The internal pressure of the system at this time is 1.5 kg
/c was 2G. Next, hydrogen was supplied to 2 kg/
After increasing the pressure to cm2G, the total pressure is 6kg/crn”G
Polymerization was carried out for 40 minutes while continuously supplying ethylene to maintain a constant temperature of 473 g in total to obtain a ferrite-containing polyethylene composition. The dried powder had a uniform gray-white color, and when observed under an electron microscope, the ferrite surface was thinly covered with polyethylene, and no aggregation of ferrite particles was observed in the polyethylene.

In addition, when this composition was measured by TGA (thermal balance), the core material filling rate was 95.2 wt%.

After that, it was placed in a hot air stream set at 120°C and heated to 2°0
Heat treatment was performed for a period of time. The obtained carrier is 106μm
It was classified using a sieve to remove aggregates.

Carrier Production Example 2 In a 112-volume autoclave purged with argon, in the same manner as in Production Example 1 (3), the titanium-containing catalyst component prepared in Production Example 1 (1) was added to 450 g of 7-nirite as titanium atoms. 0.02 mmol was added and the reaction was carried out for 1 hour. After that, a carbon blank (Ketchen black D
J-600, manufactured by Lion Akzo Co., Ltd.) 047 g was charged. Naori-pon black has a temperature of 1 at 200°C.
The product was dried under reduced pressure for several hours and made into a slurry using a dehydrated hexane trowel. Thereafter, 2.0 mmol of triethylaluminum and 2.0 mmol of diethylaluminum chloride were added, and the temperature was raised to 90°C. The system internal pressure at this time was l -5 kg/cm"G. Next, hydrogen was supplied and the pressure was increased to 2 kg/cm"G, and then,
Polymerization was carried out for 45 minutes while continuously supplying ethylene to maintain the total pressure at 6 kg/cm2, and the total amount was 469.3 g.
A polyethylene composition containing ferrite and carbon black was obtained. The dried powder had a uniform black color, and electron microscopy revealed that the ferrite surface was thinly covered with polyethylene, and the carbon black was uniformly dispersed in the polyethylene. In addition, this composition is T
As measured by GA (thermal balance), the core material filling rate was 9.
5.9wt%, and calculated from the amount of preparation, the ratio of ferrite, polyethylene, and carbon blank is 24:l:0.0
The weight ratio was 25. Thereafter, it was placed in a hot air stream set at 120° C. and heat-treated for 2.0 hours. The obtained carrier was classified using a 106 μm sieve to remove aggregates.

Carrier Production Example 3 In the same manner as in Carrier Production Example 1, the titanium-containing catalyst component prepared in (1) of Production Example I was added to 450 g of ferrite in an argon-substituted autoclave with an internal volume lα. 0139 mol was added and the reaction was carried out for 1 hour. After that, carbon black (Ketchen black) is added from the upper nozzle of the autoclave.
black) E C, manufactured by Lion Akzo) 0.
50g was added. Naori-pon black is 200℃
The sample was dried under reduced pressure for 1 hour and made into a slurry with dehydrated hexane. Thereafter, 1.0 mmol of triethylaluminum and 1.0 mmol of diethylaluminum chloride were added, and the temperature was raised to 90°C.

The internal pressure of the system at this time was 1.5 kg/cm2G. 37.5 mmol (2.1 g
) was introduced, then hydrogen was supplied, the pressure was increased to 2 kg/cm2G, and then polymerization was carried out for 28 minutes while continuously supplying ethylene to maintain the total pressure at 6 kg/cm2G, resulting in a total amount of 467 g of ferrite. and a carbon blank-containing polyethylene composition was obtained.The dried powder exhibited a uniform black color, and according to an electron microscope, the ferrite surface was thinly covered with polymer, and the carbon blank was uniformly dispersed in the polymer. It was observed that
When this composition was measured using a TGAC thermobalance,
27+l for ferrite, polymer, and carbon black:
The weight ratio was 0.03. Furthermore, when the polymer from which ferrite and carbon blank were removed by Soxhlet extraction (solvent, ky/lene) was analyzed by IH, it was found that 8w
It was confirmed that the copolymer was a polyethylene copolymer containing t% of butene.

After that, it was placed in a hot air stream set at 120°C, and 2.5
Heat treatment was performed for a period of time. The obtained carrier is 106μm
Classify with a sieve to remove aggregates.

Carrier Production Example 4 250 parts by weight of ferrite fine powder with a volume average particle diameter of 02 μm and 30 parts by weight of styrene-acrylic resin (38M73F: manufactured by Sanyo Chemical Co., Ltd.) were mixed in a Hennel mixer (10ff).
Mix well and knead using a twin-screw kneader. The obtained mixture was cooled, coarsely pulverized, finely pulverized with a hammer mill, and then coarse powder and fine powder were removed using an air classifier to obtain coating layer forming child particles with a volume average particle diameter of 2.0 μm. .

Henschelmie 1-4-(1
0(1)I: was supplied and mixed and stirred for 2 minutes at 200 Orpml to uniformly adhere the child particles around the carrier core material. Next, each particle was dispersed and supplied into a heated air stream (320'C), and instantaneous heating was performed for about 1 to 3 seconds to form a coating layer. To 100 parts by weight of the carrier having this coating layer, 2 parts by weight of a negative chargeability control agent (Bontron 5-34, manufactured by Orient Chemical Industry Co., Ltd.) was fixed to the coating layer in the same manner. This Keylia was immersed in 6N HCQ for 2 hours, thoroughly washed with water, and dried under vacuum at 60°C for 5 hours to obtain a resin-coated carrier with pores on its surface.

Carrier Production Example 5 250 parts by weight of ferrite fine powder with a volume average particle diameter of 0.2 μm was added to a thermosetting silicone resin solution (KR-255: manufactured by Shin-Etsu Silicone Co., Ltd.) based on 100 parts by weight of the resin solid content, A coating liquid was prepared by thoroughly dispersing the mixture using ultrasonic waves. Using sintered 7Elai 1 (F-200: manufactured by Powder Chick Co., Ltd., volume average particle diameter 70μll+) as the core material, the core material was coated with 2
Repeated applications were made to provide 5+wt% coverage. Thereafter, the temperature in the system was raised to 150° C. to cure the resin, thereby obtaining a thermosetting silicone resin-coated carrier in which fine ferrite powder was dispersed. This carrier was immersed in 6N HCQ for 2 hours, thoroughly washed with water, and vacuum dried at 60°C for 5 hours to obtain a resin-coated carrier having pores on the surface.

Carrier Production Example 6 A carrier was produced in the same manner as Carrier Production Example 5 except that ferrite fine powder was not added and acid treatment was not performed.

Total pore volume (m (1/g)) per gram of carrier obtained in carrier production examples 1 to 6, total pore volume per liter (I+IQ/++112) of coating layer 1+11, average pore diameter (2
1m), core material filling rate (wt%), true specific gravity (g/cm')
, bulk specific gravity (g/am”), electrical resistance and specific surface area (+
n2/g) are shown in Table 1.

(Hereinafter, blank space) Note that the total pore volume and average pore diameter of the carrier are values calculated from the measurement results of the carrier pore distribution.

The pore distribution of the carrier was determined by mercury porommetry. i
For the determination, use Pore Sizer 9310 (manufactured by Shimadzu Corporation).
The contact angle of mercury was 130° and the surface tension was 484 dyn/cm. The results are shown in FIGS. 5 to 10.

FIG. 5 is a diagram showing the relationship between pore diameter and intrusion volume. The intrusion volume represents the pore volume into which mercury is injected up to the maximum pressure at the time of measurement.

FIGS. 6 to 10 are diagrams showing the relationship between pore diameter and volume fraction. The volume fraction is the ratio of the pore volume within a certain pore diameter range to the total pore volume, expressed as a percentage.

Specific gravity measurement ・Electronic balance: Sensitivity 0.1mg.

・Pycnometer: A specific gravity bottle with a Gerussac thermometer specified in JIS R3501 (Glassware for Analytical Chemistry) with an internal volume of 50 m (1°). Constant temperature water bath: capable of maintaining water temperature at 23 ± 0.5°C.

The measurement was carried out using a measuring device with a biased bias according to the following operating procedure.

■The mass of the pre-dried pycnometer is 0.1+xg! Weigh accurately.

■Fill the vicinometer with sufficiently degassed n-hebutane,
After keeping it in a constant temperature water bath at 23±0.5°C for 1 hour,
Align the liquid surface accurately with the marked line. Take it out from the constant temperature water tank, wipe off the water from the outside, and then reduce its mass to O, l m.
Weigh accurately to the nearest g.

■Next, after emptying the pycnometer, sample 10-1
Take 5g, weigh it again accurately to the digits of 0 and 1111g, and subtract the result from (2) to find the mass of the sample.

■ Gently add 20 to 30+x (1!) of degassed n-heptane to the pycnometer containing the sample, completely covering the sample, and then gently dislodge the air in the liquid in a vacuum tencator.

■Next, the n-
Fill with hebutane and keep in a constant temperature water tank at 0.5°C for 1 hour. After accurately aligning the surface of the liquid with the marked line, take it out, wipe off the water from the outside, and reduce its mass to 0 or 1.
Weigh accurately to the milligram.

■Specific gravity is calculated using the following formula.

S = a-d/(b-c+a) Here, S: Specific gravity a: Mass of the sample (g) b = Mass when the immersion liquid is filled up to the marked line of the vicinometer (g) C: Vicinometer containing the sample Mass when filled with immersion liquid up to the marked line d: The specific gravity of the immersion liquid at 23°C is in accordance with JfS 22504.

The electrical resistance is 1 mm thick on a metallic circular electrode.

Place the sample so that the diameter is 50 mm, and the mass is 895°4.
g, 20mm diameter electrode, inner diameter 38mm, outer diameter 42m1
A guard electrode was placed on the sample, and the room temperature value after 1 minute when a DC voltage of 500 V was applied was read and converted into the volume resistivity P of the sample. The measurement environment was a temperature of 25°C and a relative temperature of 55±5%, and the measurement was repeated 5 times and the average was taken.

The specific surface area was measured by the BET method using nitrogen gas adsorption. The device used was 70-Sorb 2300 (manufactured by Shimadzu Corporation).

Evaluation of toner cleaning characteristics (equipment configuration and conditions) Organic photoconductive photoreceptor (peripheral speed 18 Cm/5e
Toner preparation example 1 using an electrophotographic printer equipped with e)
The toner obtained in steps 3 to 3 was subjected to reversal development for 20,000 sheets, and
Using the cleaning device shown in the figure, toner cleaning performance was evaluated under the following conditions, and the results are shown in Table 2 below.

a. Cleaning roller (12) ・Rotation speed: 50 rpm ・Rotation direction: Arrow (c) ・Bias voltage (Vb): '-500v ・Gap between layer thickness regulation blade: 1.3 mm ・With photoreceptor (l l) Gap: 1. Ommb, 8i stone body (13) ・Magnetic flux density of each 8-pole symmetrical magnetic pole 2 ] 000 Gauss ・Rotation speed: 11000 rp ・Rotation direction: Arrow (b) c, Toner collection roller ・DC bias voltage (Vss): -900V ・AC bias voltage (V ms) Frequency: 2KHz Peak-to-peak voltage: 1000 Vp-pd,
Carrier used: Production Example 2 Production Example 6 (Comparative Example) By applying a resin-coated carrier with pores on the surface to magnetic brush cleaning, toner remaining on the photoreceptor surface can be efficiently cleaned even if the toner has a small particle size. I can do something.

[Brief explanation of drawings]

1 and 2 are schematic cross-sectional views of the resin-coated carrier of the present invention. FIG. 3 is a schematic cross-sectional view of a conventional resin-coated carrier. FIG. 4 is a schematic cross-sectional view showing an example of a cleaning device for implementing the present invention. FIG. 5 is a diagram showing the relationship between the pore diameter of the carrier surface pores and the intrusion volume. FIG. 6 to FIG. 1O are diagrams showing the relationship between the pore diameter and volume fraction of carrier surface pores obtained in each carrier production example. Effects of the invention Patent applicant Minolta Camera Co., Ltd. Representative Patent attorney Haka Aoyama 18 Figure 3 Figure 4 → Sekisei Seminaku / E%] Figure 5 1゜Pore diameter / [Pml integral Rate/[%Coreductor/[%] 廿integral/[%]

Claims (1)

[Claims] 1. In a method of cleaning untransferred toner remaining on an electrostatic latent image carrier using a magnetic brush, a resin-coated carrier having a large number of pores on the surface is used as the carrier forming the magnetic brush. Features a magnetic brush cleaning method.