JPS6275551A - Image forming method - Google Patents

Abstract

PURPOSE:To obtain an excellent developed image with high developing efficiency by forming a magnetic brush in such a manner that magnetic particles exist in a specific amt. in a developing region and developing the latent image while the nonmagnetic toner holding the pulverous particles of another compd. existing in the direction opposite from the toner in the developing region is moved back and forth. CONSTITUTION:The compd. A has the electrostatic charge characteristic reverse from the toner and has the role to provide the intrinsic electrostatic charge to the toner and the compd. B controls the excess electrostatic charge with the toner and the magnetic particles to provide a release effect in order to process the magnetic particles. The compd. C which acts in the same manner as the compd. A in terms of electrostatic charge is held as the pulverous particles in the toner, then the pulverous particles of the compd. parts slightly from the toner in certain environment and plays the role of intensifying the electrostatic charge of the toner. The coating amt. of the magnetic particles on the sleeve surface on the down stream of a nonmagnetic blade 24 is kept at a small amt. of about 5-100mg/cm<2> in order to make substantial use of both the magnetic brush and the sleeve 22 surface. The developing brush 51 is held in the finely but vigorously oscillated state by an alternating magnetic field, by which the toner is made easily removable from the brush 51 and easily suppliable to a latent image holding body 3. The image density is improved as well.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a developing method for forming a brush of a small amount of magnetic particles on a toner holding member using a dry developer for development.

[Prior Art] Conventionally, various dry development methods have been proposed and put into practical use.

For example, in a developing method using a two-component developer, when an image area of a latent image is developed with the developer coated on the developing roller, the toner in the developer is absorbed by the developer coated on the developing roller. Uses less than a factor percent of This is extremely inefficient considering the structure of the developing device. This is because, in order to obtain a predetermined and sufficient development density, it is necessary to apply a large amount of developer to the developing roller in a constant amount and at a uniform toner density each time the developing roller rotates. For this reason, the structure of the developing device has become larger and more complicated. Of course, attempts have been made to improve the development efficiency in this type of development system as well. For example, the present applicant is
80 and has been put into practical use in the NP 8500 copier. According to this, the development density can be increased,
Although development efficiency can be increased, in the image area! Development efficiency close to 0.00% has not yet been achieved, and this type of development method still leaves room for improvement.

In terms of improved development efficiency, the l-component development method is superior to the two-component development method. Among these, in particular, in JP-A-54-43037, which was previously filed by the present applicant, a thin toner layer of 2001 or less is formed on the developing roller, and the toner applied to the sleeve L is developed to almost 100% in the image area. Develops efficiently. For this reason, the structure of the developing device could be downsized and simplified for practical use. This was achieved because a thin layer of 2001J, 11 or less, could be formed on the developing roller. However, 1
In both component development and two-component development, it is extremely difficult to form a thin layer of dry developer, and for this reason, even in one-component development, no one other than the applicant has constructed a developing device by forming a relatively thick layer. are doing. Nowadays, improvements in clarity, resolution, etc. of developed images are required in terms of image quality.
Development of a method for forming a thin layer of dry developer and an apparatus for the same is essential.

Incidentally, the above-mentioned method of the present applicant relates to the formation of a thin layer of magnetic toner. In order to make magnetic toner magnetic, a magnetic material must be added inside the tool. (magnetic materials are usually black), which causes problems such as poor color reproduction.

For this reason, as a method for forming a thin layer of non-magnetic toner, there is a method of using a cylindrical brush made of soft hair like a beaver's L, and applying the toner to the brush, or a method of applying the toner to a cylindrical brush with soft hair like a beaver's L, or a method of applying the toner to a cylindrical brush with soft hair like a beaver's L.
A method has been proposed in which a doctor blade or the like is used to apply the film to a developing roller made of .

However, when an elastic blade is used as a doctor blade for the fiber brush h, it is possible to regulate the amount of toner, but uniform application is not achieved, and the brush is only rubbed by the m fiber brush of the developing roller L. Since the toner present between the fibers is not triboelectrified, there is a problem in that fogging is likely to occur.

Further, magnetic toner can easily prevent the toner from scattering by using magnetic force, but non-magnetic toner cannot utilize magnetic force and is likely to cause toner scattering inside the machine.

The above-mentioned disadvantages occur not only during copying, but also when vibrations and shocks are applied during transport with packaging.

The present applicant has developed a developing device that is completely different from the conventional method described above, using non-magnetic toner and magnetic particles, and providing a magnetic particle restraining member opposite to the toner carrying member. A method has already been proposed in which a magnetic brush of magnetic particles is formed in the L flow of the member by the magnetic force of a magnetic field generating means, the magnetic brush is restrained by a magnetic particle restraining member, and a thin layer of non-magnetic toner is formed on the toner holding member. (Japanese Patent Application Laid-Open No. 58-143360). By this method.

We have put into practical use a method for obtaining a non-magnetic toner developed image on the surface of the latent image carrier by setting the gap between the latent image carrier and the toner carrier in the developing section to be wider than the thickness of the toner layer and applying alternating electrolysis. As a result, developing efficiency is extremely high, and color developed images can now be obtained with a small and simple developing device configuration. In particular, in two-component magnetic brush rubbing development, a high-quality vine image was obtained without rubbing marks that occur in the solid image area. Development of a method was desired.

[Problems to be Solved by the Invention] The present invention has been made in view of the conventional circumstances mentioned in 1-1. It has extremely high developing efficiency and can obtain developed images comparable to those of conventional developing methods. Particularly, the object of the present invention is to provide a simple image forming ability U that can form a stable image even under special conditions such as high temperature and high humidity, low temperature and low humidity. be.

[L stage and operation to solve the problem] In other words, the feature of the present invention is the development area of the developer carrier facing the latent image holder for holding the latent image. Add an alternating electric field between the holding body! In an image forming method in which a latent image is developed with a non-magnetic toner while the frictional charging series is 1'4, compound A is positioned 1'4 in the opposite direction to the toner with respect to the surface of the developer holding member F in the triboelectric charging series; Magnetic particles treated with Compound B located between Compound A and the toner in L are placed in the development area of the developer carrier so that the amount of magnetic particles present is 5 to IQO mg/c+a2. A magnetic brush is formed on the surface of the latent image carrier and the surface of the developer carrier and the surface of the magnetic brush formed on the surface of the developer carrier in the development area.
The image forming method involves developing a latent image while reciprocating non-magnetic toner holding fine particles of compound C located in the opposite direction to the toe with respect to the surface of the developer holding member.

The term "non-magnetic toner" as used herein refers to a toner that exhibits magnetization of 10 emp/g or less in an external magnetic field of 50,000 e and cannot substantially behave as a magnetic toner. Also, what are we talking about here? ! The area is a 10 m area centered on the closest area between the latent image carrier and the developer carrier on the developer carrier.
Refers to an area of about m.

The present inventors believe that the applicant of the present invention
After proposing 60, as a result of intensive research into its improvement, we found that in the developing section, a clear developing magnetic pole was formed to perform locally concentrated development. Frictional electrification - #Goo△ is 1 and takes place between the surface of the sleeve and ';
! Qualitatively increasing the sleeve surface area.

It has been discovered that by using the above methods, it is possible to stabilize the triboelectrification of the toner, stabilize the toner supply to the sleeve, and improve image quality such as gradation and uniformity. moreover,
When applied to the present development method, the combination of magnetic particles and non-magnetic toner used in the present invention provides good images even against environmental changes, especially changes in special environments such as high temperature and high humidity, and low temperature and low humidity. They discovered that it is effective in stably providing the following.

Although the detailed mechanism is not yet completely clear, it is generally estimated as follows based on experimental facts to date.

In other words, when processing magnetic particles, Compound A has charging properties opposite to those of the toner, so it has the role of imparting the original charge to the toner, while Compound B prevents excessive charging between the toner and the magnetic particles. It is thought that this method controls 1υ and exerts a certain degree of zero-type effect. Therefore, by appropriately controlling the treatment ratio of compounds A and B to the magnetic particles, the balance between adhesion and releasability between the toner and the magnetic particles can be controlled. however.

° Changes in environmental conditions, especially under special conditions of high temperature, high humidity, and low temperature and low humidity, can cause the difference between toner and magnetic particles. Because the electrical properties change slightly, problems such as slight fluctuations in image reflection density and increased fog may occur. To prevent this, compound A,! Although it is best to change the processing ratio of 1-B to magnetic particles according to each environment, this is not possible in reality. Shikode'T! If Compound C, which works in the same way as Compound A, is held in the toner as fine particles, the fine particles of the compound will, under certain circumstances, separate slightly from the toner and essentially become Compound A, which acts as a magnetic particle processing agent. In other environments, the presence between the toner matrix and the magnetic particles does not affect the toner's charging properties because they are in close contact with the toner matrix. Therefore, it is considered to be an appropriate charge control agent.

Hereinafter, the present developing method will be explained along with Examples. FIG. 1 shows one embodiment of the present invention. In Figure 1, 3
2 is a latent image holding member, 21 is a toner supply container, 22 is a non-magnetic sleeve, 23 is a fixed magnet, 24 is a non-magnetic blade, 2
6 is a magnetic particle circulation area limiting member, 27 is a magnetic particle, 28 is a non-magnetic toner, 29 is a developer catching container portion, 30 is a scattering prevention lI: member, 31 is a magnetic member, 32 is a developing area, 34 is a bias Indicates power supply. The sleeve 22 rotates in the b direction, and the magnetic particles 27 rotate fJ in the C direction.

This causes contact and rubbing between the sleeve surface and the magnetic particle layer, and a single layer of non-magnetic toner is formed on the sleeve surface.

Further, while the magnetic particles circulate in the C direction, a part of them is restricted to a predetermined end by the gap between the non-magnetic blade 24 and the sleeve 22, and the non-magnetic toner is applied in a single layer. That is, the non-magnetic toner is applied to both the sleeve surface and the magnetic particle Y coating surface, and the effect is substantially the same as that of increasing the sleeve surface area.

In addition, in the developing area 32, one of the magnetic poles of the fixed magnet 23
By arranging one of them to face the latent image surface, a clear development pole is formed, and toner is developed by flying onto the sleeve and from the magnetic particles by an alternating electric field. (This phenomenon will be discussed later.

) The development regressive particles and undeveloped toner are collected into the developer container as the sleeve rotates.

The sleeve 22 may be a paper tube or a cylinder made of synthetic resin, but if the surface of these cylinders is subjected to conductive treatment or made of a conductive material such as aluminum, brass, or stainless steel, it can be used as a developing electrode roller.

In the present invention, the amount of magnetic particles applied on the sleeve surface on the F flow side of the non-magnetic plate 24 is 5 to 100 mg/cm2 in order to fully utilize both the magnetic brush and the sleeve 22 surface.
It is desirable that the concentration be low, preferably about 10 to 80I1g/Cl112. If the amount of magnetic particles on the sleeve surface is too large, the regulating force of the non-magnetic blade 24 will be weakened, and the sliding force between the sleeve and the magnetic particles will be reduced, making it impossible to charge the toner smoothly. I can't. Furthermore, there is a drawback that magnetic particles also fly during toner flying development and adhere to the latent image holding member 3L. On the other hand, if the amount of magnetic particles present on the sleeve surface in the development area 32 is too small, the amount of toner applied to the development area decreases, resulting in uneven density and a decrease in image density. The amount of magnetic particles on the sleeve surface mainly depends on the gap with the sleeve 22, the position of the fixed magnet 23ON1 pole,
It can be adjusted by adjusting the magnetic force density of the S1 pole.

The method for measuring the amount of magnetic particles in the present invention will be described below. First, an ri15 brush made of only magnetic particles F was formed on the sleeve, and the magnetic particles in a portion corresponding to the development area were sucked through a cylindrical filter paper, and the weight M (mg) of the brush was measured. Next, the remaining magnetic particles on the sleeve after the magnetic particles were attracted were sampled with a transparent adhesive tape.
The occupied area S (cm2) of the attracted magnetic particles was determined.

The presence % m (mg/cm2) of magnetic particles was calculated as follows.

m = M / S The gap d between the tip of the non-magnetic plate 24 and the surface of the developing sleeve 22 at the 25th point is 50 to 700 meters, preferably 100 to 800 μm. This interval d
If it is smaller than 501, there is a drawback that magnetic particles, which will be described later, become clogged and damage the sleeve. If it is larger than 700 gm, a large amount of non-magnetic toner and magnetic particles, which will be described later, will leak out, making it impossible to form a thin layer.

In FIG. 1, 26 is a magnetic grain 7-w1 whose lower surface is in contact with the E side of the non-magnetic blade 24 and whose front end surface is an undercut surface.
It is a ring area limiting member.

Reference numerals 27 and 28 denote magnetic particles and non-magnetic toner which are sequentially contained in the toner supply container 21.

The bottom plate of the toner supply container 21 is extended below the developing sleeve 22, which is a toner holding member, to prevent toner from leaking to the outside. In addition, in order to further ensure the prevention of toner leakage to the outside, a leaked toner collection container part 28 is provided on the upper surface of the extended bottom plate to receive and restrain the leaked toner, and a leaked toner collection container part 28 is provided on the top surface of the extended bottom plate. A scattering prevention member 30 is disposed therein.A voltage to be described later is applied to this member 30.

The magnetic particles 27 have a shell with an average particle diameter of 30 to 100 IJ.
, m, preferably 40-80! It is ffi. Each magnetic particle may be made of only a magnetic material, a combination of a magnetic material and a non-magnetic material, or a mixture of two or more types of magnetic particles. By first putting the magnetic particles 7-27 into the toner supply container 21, the magnetic particles 7-27 are transferred from the toner supply container 21 in the three-face area facing into the container 21, that is, the toner supply container 21 in which the sleeve 22 is disposed. The sleeve 22 is located in the valley of the sleeve surface area from the magnetic member 31 to the tip of the IN 81 blade 24, which is a magnetic particle restraining member, to prevent leakage of magnetic particles or toner.
The magnetic particles are attracted and held by the magnetic field of the magnet 23 inside, and the magnetic particles form a layer that completely covers the sleeve surface area.

The retractable toner 28 is stored in the container 21 after the magnetic particles 27 are added thereto.
By being thrown into the sleeve 22, a large amount of the magnetic particles is stored outside the first layer of the magnetic particles 22 and exists as a second layer.

It is preferable that the first magnetic particles (27) to be charged originally contain about 2 to 70% (heavy machinery) of non-magnetic toner 28 based on the magnetic particles, but they may also contain only magnetic particles. Furthermore, once the magnetic grains 7-27 are attracted and held as a magnetic AF layer on the sleeve surface area, they will not substantially shift to one side even if the device is vibrated or the device is tilted considerably.
A shape that completely covers the sleeve surface area is maintained.

With the magnetic particles 27 and the non-magnetic toner 28 sequentially placed in the container 21 as described above, the magnet 2
A magnetic brush of magnetic FLf is formed in the magnetic particle layer near the sleeve surface corresponding to the position of the magnetic pole S2 of No. 3 by the strong magnetic field of the magnetic pole.

In addition, even when the sleeve 22 is rotated in the direction of the arrow, the magnetic particle layer near the tip of the non-magnetic plate 24, which is a magnetic particle regulating member, is affected by gravity, magnetic force, and the non-magnetic plate 24.
Due to the balance between the regulating force based on the effect caused by the presence of the sleeve 22 and the conveyance force in the direction of movement of the sleeve 22, it accumulates at the point 25 on the surface of the sleeve 22, forming a stationary layer that can move to some extent but is difficult to move.

When the sleeve 22 is rotated in the direction indicated by the arrow, by appropriately selecting the arrangement position of the magnetic pole and the fluidity and magnetic properties of the magnetic grains 127, the magnetic brush circulates in the direction of the arrow C near the magnetic pole S2. form a layer. In the circulating layer, the magnetic particles relatively close to the sleeve 22 are
2, the magnetic flux rises from the vicinity of the magnetic pole S2 to the north of the stationary layer on the rotationally downstream side of the sleeve. In other words, it receives a force pushing up toward the L portion. Since the upper limit of the circulation area of the pushed-up magnetic particles is determined by the magnetic particle circulation area limiting member 26 provided at the L portion of the non-magnetic blade 24, the magnetic particles ride on the non-magnetic blade 24 and move upward. Instead, it falls due to gravity and returns to the vicinity of the magnetic pole s2. In this case, magnetic particles that are located far from the sleeve surface and receive a small push-off force may fall off before reaching the magnetic particle circulation area limiting member 26. In other words, in the circulation layer, the magnetic brush of the magnetic particles undergoes 'XIQ' as shown by arrow C due to the magnetic force and frictional force due to gravity and magnetic poles, and the fluidity (viscosity) of the magnetic particles. Toner layer 1 to non-magnetic toner 2
8 is taken in one after another, and the developer supply 8 is returned to the do part in 21.
Thereafter, this circulation is repeated as the sleeve 22 is rotated.

As the developing bias voltage 34, an alternating voltage whose positive and negative peak voltages are the same, or a DC voltage superimposed on this alternating voltage can be used. For example, dark area latent image potential -600v
For an electrostatic latent image with a bright area latent image potential of -200V, for example, by superimposing a DC voltage of -300V on the sleeve 22, the waveform peak voltage Vp, 300 to 20QOV, frequency 2
An alternating voltage selected in the range of 00 to 3000 Hz is applied to maintain the photosensitive drum 3 at the set potential. -In the crotch,
The electrical resistance of the G1 brush is relatively high<(+08ΩCff
greater than 1), in this case the current * / (Ias's beak 'tt
The higher the i pressure width vpp is, the better (for example, 800 ■ l:)
and the frequency is Boo)lz or less, preferably 800H
When the frequency is higher than z, more preferably 1 kHz or higher, a good image quality with sufficient density can be obtained. However, even if only vpp is high, if the frequency is low, the density is low and it is difficult to obtain good image quality. In any case, the upper limit of V911 is determined by the gap discharge limit value of the developing section, and the lower limit is determined by the toner flight limit value on the sleeve L and magnetic particles.

Taking into account the above, the resistance of the entire developing magnetic brush is such that the resistance in the thickness direction of the developing brush is 108 ΩCal or more when the developing brush is in contact with the latent image holder 1.
It is preferable that it is D.

Incidentally, the resistance value of the magnetic particles/magnetic brush mentioned in the present invention refers to the resistance value of the magnetic particles/magnetic brush when the developing device shown in FIG.
Form a magnetic brush with 50mg/cm2 magnetic particles,
A conductive metal drum is provided opposite the developing sleeve with a gap 3004, and a resistor of approximately LMΩ is connected in series with the drum. Calculated from the current value flowing when a voltage of 200 VDC is applied to the circuit. This is what I asked for.

Hereinafter, phenomena in the developing section 32 will be described regarding the developing method according to the present invention.

FIGS. 2 and 3 are enlarged explanatory views of the developing section of the developing method according to the present invention. 50 is the latent image charge in the dark area of the latent image carrier. 28 is a non-magnetic toner. 34 is an alternating voltage power source on which a DC component is superimposed. Figure 2 shows sleeve 2
When the positive waveform component of the alternating voltage is added to 2, the 3rd
The figure shows the case where a negative waveform component of the alternating voltage is added. The polarity of the latent image charge is shown as negative, and the polarity of the developer is shown as positive.

The resistance of the developing brush 51 is relatively large (approximately 108 Ωcm)
Therefore, depending on the charging/discharging time constant of the electric charge due to the material of the developing brush 51 itself and other factors, the developing brush 51 has friction with the toner 28 (heavy charge or mirror charge, latent image holder 3, There will be charges injected by the latent image electric field of h and the alternating electric field between the latent image carrier 3 and the sleeve 22.

When the electric field due to the latent image charge 50 in the dark area on the latent image holder 3 matches the electric field due to the alternating electric field, the developing brush 51 is in the maximum bending state in the direction of the sleeve 22 .

When the electric field due to the latent image charge on the latent image holding member 3 and the electric field due to the alternating electric field do not match in direction, the bending of the developing brush 51 becomes small.

In any case, as mentioned above, the developing brush 5 is
1 is in a state of minute but intense vibration, and the fog toner that has adhered excessively to the latent image holder 3 is rubbed by the developing brush and removed from the latent image holder 3, and is returned to the brush L. Further, due to the vibration of the brush, the toner is easily separated from the brush 51 and is easily supplied to the latent image holding member 3, so that the image density also decreases. Further, the toner is removed within the brush 51 by the first vibration of the brush 51, which interferes with improving image density and preventing ghosts.

Furthermore, if this vibration state is severe, a portion of the magnetic brush comes off from the brush or the sleeve, causing reciprocating motion between the latent image holder and the sleeve surface. The kinetic energy of this reciprocating brush is large and efficient, and the above-mentioned vibration effect is expected. The behavior of the magnetic particles in the developing section is a phenomenon observed as a result of high-speed photography at 8000 frames per second using a high-speed camera.

The magnetic particles for toner application used in the present invention include, for example, surface oxidized or unoxidized iron, nickel, cobalt,
Metals such as manganese, chromium, and H-class metals, and alloys or resistant materials thereof can be used. Moreover, there are no special restrictions on the manufacturing method.

Compounds A, B, and C vary depending on the material of the surface of the toner holding member and the toner material.
．． When using metals such as aluminum and stainless steel as the +f member, if the toner is positively charged, compounds A or C include polytetrafluoroethylene, monochlorotrifluoroethylene polymer, borif, vinylidene chloride, silicone resin, polyester. Compound B includes styrene resins, acrylic resins, polyacids, silicone resins, polyvinyl butyral, etc., such as resins and metals of ditertiary-butylsalicylic acid.If the toner is load-centered, compounds A or C can be used. ,
Nigrosine, aminoacrylate resin, acrylic resin,
It is appropriate to use styrene resin, silicone resin, polyester resin, etc. as the compound B of basic dyes and their lakes, but the present invention is not necessarily limited thereto.

Further, it is preferable that the positions of the triboelectric series t- of the compounds A and C be close to each other, and it is sufficiently possible that the compounds A and C have substantially the same chemical structural formula.

The total amount of L combination compounds A and B to be treated is 0.1 to 30 percent by weight (preferably 0
．． The weight ratio of compounds A and B is 10:90 to 99':1 (preferably 20:1).
80-90:10 particularly preferably 30 near 0-80:2
0) is desirable.

Treatment methods using compounds A and B include a method of mixing the powder and melting or softening it with heat to make it adhere to the magnetic particles, a method of dissolving or suspending it in a solvent and applying it to make it adhere to the magnetic particles; Any method known in the art for carrier particles can be applied.

Next, a method for measuring the amount of triboelectric charge according to the present invention will be described.

The surface treatment substance of the toner and magnetic particles-f is substantially recycled.
- Pulverized and classified so that it can be considered as particle size. As for the particle size, the average number of particles is 9 to 9 when measured using a Coulter counter.
11 tiles 9 volume average 13~15pm, 8.35g
The number distribution below m was set at 20% or less, and the volume distribution after 20.2 pm was set at 15% or less.

FIG. 4 is an explanatory diagram of the frictional charge amount measuring device.

A metal measurement chamber 'JA12 with a conductive screen 13 of 400 meshes (can be changed as appropriate to a size that does not allow magnetic particles to pass through) at the bottom is filled with the toner whose triboelectric charge amount is to be measured or a substance for surface treatment of the above-mentioned magnetic particles. and 200-300
Irregular iron powder with a particle size between meshes (EFV 2 manufactured by Nippon Iron Powder)
00/300. The surface is untreated, similar to the toner carrier,
1゛1ra no MaP! A? There is virtually no iF conductivity) of ((
About 4 g of a mixture (developer) with a jjIX ratio of 1:9 is added and a metal lid 14 is closed. The weight of the entire measuring container 2 at this time
11 is a lumber hat (g). Next, the suction machine 11 (jll
At least the portion in contact with the fixed container 2 is an insulator), suction is applied from the suction port 17, and the pressure of the vacuum gauge 15 is set to 70 mmHg by adjusting the XH regulator 16. In this state, suction is applied sufficiently (for about 1 minute) to remove the surface treatment substance of the toner or magnetic particles. At this time, the scale was 19.
Let the potential of be V (volt). Here, 18 is a capacitor, and the capacitance is C (μF). Furthermore, the weight of the entire measurement container after suction is calculated and is defined as W2 (g).

This frictional charge amount T (Cog) is calculated as shown in the f formula.

However, the measurement conditions are 23° C. and 50% RH.

On the other hand, in order to retain Compound C in the toner, it is desirable that the average particle size of the compound C be fine particles of 5 gm or less, more preferably 1 pLffl or more. Furthermore, the fine particles of compound C are 0.01 to 5 particles 1;
parts, more preferably 0.05 to 2 parts by weight.

If Compound C is not added to the toner in the form of fine particles as described above, the object of the present invention may not be fully achieved.

On the other hand, as the fixing resin for the toner used in the present invention,
'rim aggregation of styrene and its substituted products such as polystyrene, polyp-chlorostyrene, and polyvinyltoluene;
Styrene-p-chlorostyrene copolymer, styrene-propylene copolymer, styrene-vinyltoluene copolymer, styrene-vinylnaphthalene copolymer, styrene-methyl acrylate copolymer, styrene-ethyl acrylate copolymer, Styrene-butyl acrylate copolymer, styrene-octyl acrylate copolymer, styrene-methacrylic methyl copolymer, styrene-ethyl methacrylate copolymer, styrene-phthyl methacrylate copolymer, styrene-acryl-amino copolymer Acrylic copolymer, styrene-aminoacrylic copolymer, styrene-alpha chloromethyl methacrylate copolymer, styrene-acrylonitrile copolymer, styrene-vinyl methyl ether copolymer, styrene-vinylethyl ether copolymer , styrene-vinyl methyl ketone copolymer, styrene-butadiene copolymer, styrene-isoprene copolymer, styrene-
Styrenic materials (polymers; polymethyl methacrylate, polybutyl methacrylate, polychlorinated bean, polyvinyl acetate, polyethylene, polypropylene, polyester, polyurethane,
Polyamide, epoxy resin, polyvinyl butyral, polyacrylic acid resin, rosin modified rosin, terpene resin,
Phenol resin, aliphatic or alicyclic hydrocarbon resin, aromatic petroleum resin, J1! Chlorinated paraffin, paraffin wax, etc. can be used alone or in combination.

In toners, any suitable pigment or dye can be used as a colorant. For example, carbon blank,
There are known facial cleansers such as iron black, phthalocyanine blue, ultramarine, quinacridone, and benzidine yellow.

In addition, as a charge control agent, amino compounds, quaternary ammonium compounds, and organic dyes, especially basic dye 1 and its salts, pencil dimethyl-hexadecyl ammonium chloride, decyl-trimethyl ammonium chloride, nigrosine base, nigrosine hydrochloride, safranin γ, crystal violet, metal-containing dyes, salicylic acid-containing compounds, etc. may be added. Furthermore, magnetic powder may be added to an extent that does not impede the effects of the present invention.

The above toner structure may be used as a toner produced by a commonly used mixing-pulverization method, or may be used as a wall material or a core material of a microcapsule toner, or both.

[Examples] The present invention will be explained in more detail with reference to Examples. -1------- The developing device shown in FIG. 1 was used. In the embodiment device, the photoreceptor 1-ram 3 is oriented 601 in the direction of arrow a.
It rotates at a circumferential speed of 1III/sec. 22 has an outer diameter of 32 mm and rotates in the direction of the arrow at a circumferential speed of F3Brarm/sec.
The sleeve is made of stainless steel (SOS 304) with a thickness of 0.8 mm, and its surface is subjected to amorphous sandblasting using #600 Aranta 1 and abrasive grains, and the roughness of the circumferential surface is reduced to 0.8 μm CRz. =).

On the other hand, a sintered ferrite type magnet 23 was fixedly disposed inside the rotating sleeve 22, and the magnetic pole arrangement 6 was as shown in FIG. 1, and the maximum value of the surface magnetic flux density was about 800 Gauss.

The non-magnetic blade 24 is made of non-magnetic stainless steel with a thickness of 1.2 mm, and the amount of magnetic particles on the sleeve is 30 to HB/cm2.
The blade-sleeve gap is 300.
It was set as 1Lr5.

On the surface of the photosensitive drum 3 facing this sleeve 22,
Dark area -600v' as an electrostatic latent image? 1% light area - 150v
A charge pattern is formed, and the distance from the sleeve surface is set to 300
It was set to ILrrr. Then, a voltage with a frequency of 800 Hz, a peak-to-peak value of 1.4 KV, and a center value of 1,300 V was applied to the sleeve by the power source 34 to perform development.

Example 1 Crery I copolymer (80:17:3) Rhodamine pigment 5 parts by weight, average particle size 13ILI! To 100 parts by weight of a red fine powder of 100 parts by weight, a portion of 1.0 parts by weight of positively charged colloidal silica was added to prepare a toner. Frictional charging of toner JIY is +
It was 23.5 (ILc/g).

Next, as magnetic particles, 100 parts of ferrite grains with a particle size of 50 to 70 ω were mixed with styrene-methyl methacrylate 〇, 5 7J'E.
A sample was prepared by heating and drying a part (claw combined (30 near 0) (friction power i? electric power + 3.8 C/g).

When applied to the developing device shown in Figure 1 and produced an image,
A clear image with good gradation without fogging was obtained, and the 1-image reflection C degree was 1.28. Further, in order to examine the durability of the developer, a durability test of 10,000 sheets was performed, and a clear image (image density 1.26) without fog was obtained, which was the same as the initial image. On the other hand, a high temperature and high humidity environment (30℃, 90%RH)
) When the image was produced in the same manner with 'T, the image density was 1.25, and an image without the problem of fogging was obtained. In addition, even in a low-temperature, low-humidity environment (10°C, 110%), the i-! I got hit.

Example 2 The same procedure as in Example 1 was performed except that the coating resin for the magnetic particles was used, and the same good results were obtained. It was done.

Example 3 Polyester resin 100,000 φ parts Phthalocyanine pigment 3 parts by weight Flat diameter I
A toner was prepared by adding 0.5 parts by weight of co-roytal silica to 11 parts by weight of colored grains/-100 tons.

The amount of triboelectric charge was -27.3 C/g.

In addition, styrene-dimethylaminoethyl acrylate-0.5 parts by weight combination (97:3) (friction band "ITi +3
5.6 pots Cog) Styrene-butyl methacrylate copolymer 1.0 parts by weight (80:2
0) (-1,1 Cog) was coated on the surface of ferrite particles in the same manner as in Example 1 to obtain magnetic particles.

Toner L 100i [Zff part, L styrene dimethic part and 7-100 parts by weight of magnetic particles are mixed and applied to the developing device of FIG.
Frequency 800 toward the static latent image of bright area +150■
Hz, peak-to-peak value 1.4KV, center value +30
When a voltage of 0 V was applied and development was performed, good results similar to those of Example 1 were obtained.

Effects of the Invention As explained above, according to the present invention, a developing device using magnetic particles with a simple configuration can be used with a small amount of J□1.
By interposing the magnetic particles in the development area, it was possible to obtain good image quality without blurring, good gradation, and no negative characteristics in various environments.

Also, stop by for development! Magnetic particles F-
By efficiently distributing the toner with kl and performing flying development from both, it was possible to achieve a development efficiency of nearly 100% in an alternating electric field. This allows for miniaturization and simplification of the developing device configuration.

Also, by at least an alternating field, the brush of magnetic particles according to the present invention was brought into contact with the latent image carrier and vibrated, thereby being able to remove the ground force brittlener magnetized to the Wl image carrier.

[Brief explanation of drawings]

Fig. 1 is a longitudinal sectional front view of a developing device according to the developing method according to the present invention, Figs. It is an explanatory diagram. --3...Latent image holding member, 11...Suction device, 12...Measurement container, 13...Conductive screen, 14...Metal lid, 15...
Vacuum gauge, 16... Air volume control valve, 17... Suction port, 1
8... Capacitor, 19... Electrometer, 21...
Developer supply container, 22... Non-magnetic sleeve, 23...
- Fixed magnet, 24... Non-magnetic blade, 26... Magnetic particle-circulation area limiting member, 27... Magnetic particle-128
...Nonmagnetic toner, 29...Developer collection container section, 3
0...Scatter prevention member, 31...Magnetic member, 32...
-Development area, 34...bias power supply, 50...electrostatic latent image, 51...magnetic brush.

Claims (1)

[Claims] The latent image is developed with non-magnetic toner while applying an alternating electric field between the developer carrier and the latent image carrier in the development area of the developer carrier facing the latent image carrier for holding the latent image. In the image forming method, a compound A is located in a direction opposite to the toner with respect to the surface of the developer holding member in the triboelectric charging series, and a compound B is located between the compound A and the toner in the triboelectric charging series. A magnetic brush is formed in the development area of the developer carrier with magnetic particles treated with the magnetic particles so that the amount of the magnetic particles is 5 to 100 mg/cm^2, and in the development area, the latent image carrier and the developer are Holding fine particles of compound C located in a direction opposite to the toner with respect to the surface of the developer holding member in a triboelectrification series between the surface of the developer carrying member and the surface of the magnetic brush formed on the surface of the developer carrying member. An image forming method characterized by developing a latent image while reciprocating non-magnetic toner.