JPS60131553A - Developing method - Google Patents

Abstract

PURPOSE:To form a fine particle developer layer forming a good tuft and to obtain an image high in quality by forming a developer in a cloud state with a repulsing magnetic field and regulating the binary magnetic developer layer with a tuft-pressing member. CONSTITUTION:A binary developer moving together with a sleeve 2 is formed into a cloud state by a repulsing magnetic field caused by the same polarity magnets, such as N poles of a magnets 3, and the top of the tuft is made higher. This height is regulated with a pressing plate 21 to smooth the developer layer of a roughened state, and to form a uniform and good tuft, and when the fine particles of both toner and carrier are vibrated and moved, the toner particles do not attach to the background of an image, agglomeration of the toner particles is prevented, and further, the carrier particles do not attach to the electrostatic image parts, thus permitting a sharp high-quality image having delicate lines and points and density differences, etc. reproduced in high fidelity to be formed.

Description

[Detailed description of the invention] [Public funds for industrial use] The present invention relates to an improvement in a method for developing an electrostatic latent image or a magnetic latent image in an electrophotographic copying device, etc.
A two-component developer, t'IA, containing a mixture of magnetic media particles and toner particles is supplied to the surface of the developer carrier to form a developer layer on the developer carrier.

The present invention relates to an improvement in a method of developing an electrostatic or magnetic image on the surface of an image carrier using the developer layer.

□Prior art□〕・ □゛As an example, developing method in an electrophotographic copying machine□・
An overview of the law will be explained. First of all, general magnetic brush development.In the magnetic brush development method using a two-component developer, it is relatively easy to control the triboelectric charging of toner particles, and the agglomeration of toner particles occurs. The brush's bristles stand out well, it has excellent abrasion properties on the surface of the image carrier, and it has a sufficient cleaning effect even when used for cleaning, so it is important to manage the amount of toner particles relative to carrier particles. Although it is necessary, it is widely used. Note that this developing method has conventionally used a developer consisting of magnetic carrier particles with an average particle size of several tens to several hundreds of micrometers and non-magnetic toner particles with an average particle size of tens of micrometers. Developers have a problem in that it is difficult to obtain high-quality images that reproduce delicate lines, dots, shading differences, etc. because the toner particles and even the intermediate particles are coarse.

Therefore, in order to obtain high-quality images using this developing method, conventional methods have been used, such as coating the carrier particles with resin, improving the magnet body that supports the developer transport carrier, and examining the bias voltage for the developer transport carrier. Although much effort has been made, the reality is that it is still not possible to obtain images that are stable enough to add KW11.
In order to obtain high quality images, it is believed that it is necessary to make the toner particles and carrier particles finer.

However, toner particles with an average particle diameter of mμm or less, especially 1
If the particle size is less than 01 g + rlL, ■ Van der Waals force will be affected by the Coulomb force during development, and so-called fog will occur where toner particles will adhere to the ground area of the image background, which will hinder the developer transport. It is difficult to prevent fogging even by applying a DC bias voltage to the carrier.
- Frictional charging of toner particles is less controlled and agglomeration is more likely to occur. In addition, the carrier particles become fine particles (and the carrier particles also become attached to the electrostatic image area of the image bearing member. The reason for this is that the force of the magnetic bias decreases, causing the carrier particles to form together with the toner particles. This is thought to be due to the carrier particles adhering to the image carrier side. Note that as the bias voltage increases, carrier particles also begin to adhere to the ground portion of the background.

Micronization has the problem that the above-mentioned side effects are more noticeable and clear images cannot be obtained, so it is difficult to actually use micronization of toner particles and carrier particles. there were.

[Purpose of the invention]

The present invention provides toner particles that do not cause the above-mentioned problems even when using a developer in which toner particles and carrier particles are finely divided, that is, toner particles having an average particle size of 1 μm or less, further 10 μm or less. The above problems of ■ and ■ do not occur even when using
□ Even if the carrier particles below and below the μ door are used, the trouble caused by ② does not occur, and therefore, it is possible to obtain clear, high-quality images that faithfully reproduce delicate lines, points, and differences in shading. This is to provide a developing method that can be used.

[Structure of the invention]・1.

In the present invention, a two-component developer consisting of magnetic carrier particles 1 and toner particles is supplied onto the surface of a developer transporting carrier to form a developer layer.1. In the method of developing a latent image on the image bearing surface by placing the developer layer on the surface of the developer transporting carrier under vibration and an electric field, a counter-magnetic field is formed, and a holding member is provided. The developing method of the present invention is characterized by using magnetic carrier particles of a two-component developer and performing development under an oscillating electric field.
This makes it possible to use micronized magnetic gear particles and toner particles without any pull, and it should be noted that the developer used in the method of the present invention must have the gear and toner under the appropriate conditions described below. stomach. ,.

〔Example〕,,.

Regarding carriers, by using magnetic carrier particles, it is possible to improve the agitation performance of toner and carrier and the transportability of developer, and also to improve the charge control performance of toner, and toner particles. However, if the average particle size of general magnetic carrier particles is large, the magnetic plastic particles formed on the Φ developer transporting carrier may Even if an electrostatic image is developed while being vibrated by an electric field, it is easy for the toner image to have smear (2) The toner level in the ears is low, so high-density development is not possible. Problems such as not being able to be used occur.・The sum that eliminates M during this Φ can be made as small as the average particle size of the carrier particles, and as a result of experiments, the effect is effective when the average particle size (factor) is less than μm. beginning to appear.

In particular, it has been found that when the temperature is less than 1 μm, the problem of °O does not substantially occur. In addition, the problem @ is also solved by making the magnetic carrier finer particles, which increases the toner concentration in the spikes and enables high-density development. However, if the particles are too fine, they may adhere to the image bearing surface together with the O toner particles, or
It may become easier to scatter. These phenomena are also related to the strength of the magnetic field acting on the carrier particles and the strength of the magnetization of the carrier particles due to the magnetic field K, but in general, the tendency gradually increases when the average particle size of the carrier particles becomes 15βm or less. At the beginning,
If it is less than 5 μm, it will appear on the surface and become 5. A portion of the carrier particles adhering to the image bearing surface is transferred onto the recording paper together with the toner, and the remaining part is removed from the image bearing surface along with the residual toner by a cleaning device such as a blade or fur brush. With carrier particles made only of magnetic material, there is a problem that (1) the carrier particles that have migrated onto the recording paper are not fixed on the recording paper by themselves and are likely to fall off, and that the intermediate particles remaining on the surface of the θ image carrier are When removed by cleaning equipment,
There is a problem in that the surface of the image bearing member located at the bottom from the photoreceptor is easily damaged. These problems of ◯ and ◯ can be solved by forming magnetic carrier particles together with a substance that can be fixed to recording paper, such as resin. In other words, the magnetic carrier particles adhere to the recording paper by coating the magnetic particles with a substance that can be fixed to the recording paper, or by being formed of a substance that can be fixed to the recording paper containing dispersed magnetic powder. The carrier particles that have been removed are also fixed by heat and pressure, and the surface of the image carrier is not damaged even when the carrier particles are removed from the surface of the image carrier by a cleaning device. In such magnetic carrier particles, the carrier particles have an average particle size of 5 to 15 μm or less, and even if the carrier particles migrate to the image bearing surface or the recording paper, the problem of O mentioned above can be practically avoided. It hardly causes any trouble. Incidentally, in the case where the above-mentioned slag adhesion occurs, it is effective to provide a recycling mechanism.

From the above, the average particle size of the magnetic carrier is μm.
The appropriate conditions are particularly preferably 30-5 μm or more, and it is also preferred that the magnetic carrier particles contain a substance that can be fixed on the recording paper. The average particle size is the weight average particle size, and the average particle size is the weight average particle size.
, was measured using Omnicon Alpha (manufactured by Posilom).

Such magnetic carrier particles may contain metals such as iron, lithium, cobalt, etc., or compounds or alloys thereof, such as triiron tetroxide, r - Particles of ferromagnetic or paramagnetic substances such as ferric oxide, chromium dioxide, manganese oxide, ferrite, manganese-copper alloy, or the surface of these magnetic particles, such as snarene resin, vinyl resin, ethyl resins, rosin modified resins, acrylic resins, polyamide resins, resin resins, polyester resins, etc. tn [1m
It can be obtained by making particles of a resin or fatty acid wax containing dispersed fatty acids such as balmicinic acid and stearic acid, and sorting the particles by particle size using a conventionally known mean particle size classification method. .

Note that forming the carrier particles from resin etc.
In addition to the effects described above, the developer layer formed on the developer transport carrier becomes uniform, and a high bias voltage can be applied to the developer transport carrier. The reason why the carrier particles are made into particles by resin etc. is that (1) Generally, carrier particles tend to be magnetized and attracted in the long axis direction, but when they become spherical, the directionality becomes non-existent, and therefore, the developer The layer is formed uniformly, preventing the occurrence of locally low resistance areas and uneven layer thickness.C) Along with the high resistance of the medium particles, the edge parts seen in conventional carrier particles are eliminated. As a result, even if a high bias voltage is applied to the 3J1gII agent transport carrier, the electric field will not be applied to the edge part, and the electrostatic latent image will be disturbed due to discharge on the image bearing surface, or the bias voltage will be reduced. I don't want to break down!) The fact that it is possible to apply the erodible ink at a high pressure of 4 to 1 ink means that when the development under an oscillating electric field in the present invention is performed by applying an oscillating bias voltage, This means that the effects described below can be fully exerted.

As mentioned above, wax can also be used as the carrier particles that produce the above-mentioned effect '4, but from the viewpoint of the durability of the carrier, it is preferable to use resin as mentioned above. Further, it is preferable that insulating magnetic particles are formed so that the carrier particles have a resistivity of 10'Ωα or more, particularly 1091 or more.

This resistivity is calculated by applying 1 kg onto the candied particles after placing the particles in a container with a cross-sectional area of 0.50 m and tapping.
Apply a load of /c: and set a distance of 1000 between the load and the bottom electrode.
V/ is a value obtained by reading the current value when applying a voltage that generates an electric field.If this resistivity is low, when a bias voltage is applied to the developer transport carrier, the carrier particles Km charge will be When injected, carrier particles tend to adhere to the surface of the image carrier, or breakdown of the bias voltage tends to occur.

Taking all the above into account, the magnetic carrier particles are spherical so that the ratio of the long axis to the short axis is 3 times or less, and there are no protrusions such as needles or edges (and the resistivity is 10'). The appropriate condition is Ωα or more, preferably 0saΩ or more.Then, such magnetic particles are spherical magnetic particles with high resistance or magnetic particles in the resin liquid W1. For carriers with magnetic fine particle dispersions, use magnetic fine particles as much as possible and perform spheroidization treatment after forming the dispersed resin particles, or spray dry. It is manufactured by obtaining dispersed resin particles by the method described in the following.

Next, regarding toner, in general, as the average particle size of toner particles becomes smaller, the amount of charge qualitatively decreases in proportion to the square of the particle size, and the adhesion force such as van der Waals force increases. This makes it difficult for the toner particles to be separated from the carrier particles, and once the toner particles adhere to the non-image area of the image bearing surface, they cannot be easily removed by rubbing with a conventional magnetic pusher. In the conventional magnetic brush development method, this problem became noticeable when the average particle size of the toner particles became 10 μm or less.The development method of the present invention solves this problem. agent layer,
Developing with a so-called magnetic brush is done under a vibrating electric beam at 5tC.
I'm trying to resolve it by doing this. That is, the toner particles adhering to the developer layer are easily moved (and easily separated) from the developer layer to the image area and non-image area on the image carrier surface due to electrically applied vibrations. If the surface of the image carrier is rubbed with the developer layer, particles attached to the non-image area of the image carrier can be easily removed or moved to the image area, and the developer layer can be easily removed or moved to the image area. When the agent layer thickness is formed to be thinner than the gap between the image carrier surface and the developer transport carrier surface, toner particles with a low charge amount will hardly migrate to the image area or non-image area, and Because it does not rub against the surface of the image carrier, it does not adhere to the image carrier due to triboelectric charging, and even toner particles of about 1-100 g can be used.5 Therefore, it is possible to form an electrostatic latent image with high fidelity. It is possible to obtain a clear toner image with good reproducibility that is developed with high reproducibility.Furthermore, since the oscillating electric field weakens the bond between toner particles and carrier particles, the adhesion of carrier particles to the image bearing surface due to toner particles is also reduced. .

@ K s If the thickness of the developer layer is made thinner than the gap between the image carrier surface and the developer transport carrier surface, the image area and non-111
In the 8-part area, toner particles with a large amount of charge vibrate under the oscillating electric field, and depending on the strength of the electric field K, the carrier particles also move, so that the toner particles selectively transfer to the image area on the image carrier surface. In addition, the adhesion of carrier particles to the surface of the image bearing member is greatly reduced (not significantly reduced). - Particles may reach the non-image area. The same is true for cow yaya. Therefore, there is a problem that the developer is likely to fly away. The developer transported to the developing section is transported as fast as possible It is necessary to make the first world smaller.

On the other hand, if the average particle size of the toner is large (as mentioned earlier, the roughness of the jKlI image becomes noticeable).

Normally, for developing fine lines arranged at a pitch of about 10 lines/snow seal with high resolution, there is no practical problem with a powder having an average particle size of about 1 μm (73). When toner is used, resolving power is significantly improved, and it becomes possible to provide clear, high-quality images that faithfully reproduce differences in shading and the like. For the above reasons, the appropriate condition for the particle size of the toner is that the average particle size is 10 μm or less, preferably 10 μm or less. Further, in order for the toner particles to follow the electric field, it is desirable that the average charge amount of the toner particles be larger than 1 to 3 μC/11 (preferably 3 to 300 μC/11). If the particle size is small, a high charge amount is required.

Such toner can be obtained in the same manner as conventional toner. That is, it is possible to use a toner in which spherical or amorphous nonmagnetic or magnetic toner particles in conventional toners are sorted by an average particle size sorting means.

Among these, it is preferable that the toner particles are magnetic particles containing magnetic particles, particularly when the amount of magnetic fine particles is 0% by weight.
Preferably, it does not exceed . When the toner particles contain magnetic particles, the toner particles are affected by the magnetic force of the magnet included in the developer transport carrier.
The ability to uniformly form the magnetic brush is further improved, fogging is prevented, and toner particles are less likely to scatter. However, if the amount of magnetic material contained is too large, the magnetic force between it and the carrier particles will become too large.
It will not be possible to obtain a sufficient developing density, and fine magnetic particles will appear on the surface of the toner particles, making it difficult to control triboelectric charging, making it easier to damage the toner particles, and causing damage to the carrier particles. It becomes easy to aggregate between the two. In particular, when using color toners, the magnetic weight must be less than % of the weighted amount or a clear color image cannot be obtained.

To summarize the above, a preferable toner in the developing method of the present invention uses a resin as described above for the carrier and further fine particles of a magnetic material, and a coloring component such as carbon and, if necessary, charge control etc. are added thereto. The toner particles can be produced by a method similar to a conventionally known method for producing toner particles, and consist of particles having an average particle diameter of 20 μm or less, particularly preferably 10 μm or less. Furthermore, spherical toner brings about favorable results in terms of improved fluidity, agitation, transport, and charging of the developer.

In the developing method of the present invention, it is preferable to use a developer in which carrier particles and toner particles as described below are mixed in the same proportions as in the conventional two-base development process, but this K is also necessary. Depending on the conditions, a fluidizing agent for improving the fluidity and sliding of particles, a cleaning agent for cleaning the surface of the image bearing member, etc. are mixed. As a fluidizing agent, cotetraidal silica, silicon face, metal stone, or a nonionic surfactant can be used, and as a cleaning agent, fatty acid metal salt, organic group-substituted silicon, fluorine, etc. can be used. Surfactants and the like can be used.

The above are the conditions for the developer, and next, the conditions for the developer transport carrier that forms a developer layer with such developer to develop the electrostatic image on the image carrier will be described.

A developer transport carrier similar to that used in conventional development methods to which a bias voltage can be applied is used, but in particular, a developer transport carrier having a plurality of magnetic poles inside a sleeve on which a developer layer is formed is used. A structure in which a rotating magnet is provided is preferably used. : In such a developer transport carrier, the developer layer formed on the surface of the sleeve moves in an undulating manner due to the rotation of the rotating magnet, so new developer is supplied one after another. Even if there is some unevenness in the developer layer on the sleeve surface,
This effect is sufficiently covered by the above-mentioned wave-like undulations so that it does not become a problem in practice.

However, in this developer conveying means, since the magnet body is rotated at high speed, problems arise in the rotating mechanism, such as requiring high rotational torque and being susceptible to vibration. It is desirable to use a conveyance method in which the sleeve is rotated while the sleeve is demagnetized and fixed to the rectangular shape, but when the conventional magnetic pole configuration is used, it is difficult to obtain uniform layer formation equivalent to the rotation of the magnet body.

The present invention provides a method for forming a uniform developer layer in a developer transport method in which a sleeve is rotatably moved while a magnet is fixed.

It is known that when magnets of the same polarity are disposed close to each other in a sleeve, a repelling magnetic field is formed, and the developer moving together with the sleeve moves in an almost diagonal state between them. In this state, the developer layer is rough and the spikes are formed flat, so the developed image is not good. Furthermore, the gap between the image carrier and the sleeve becomes larger, and the electrode effect becomes more difficult to obtain, making it difficult to obtain sufficient image density. The present invention is a developing method in which a plate-like member is installed upstream of a repulsion magnetic field forming section to obtain a uniform developer layer while maintaining a cloud state due to a repulsion magnetic field.

FIG. 1 shows the structure of a developer layer on a sleeve due to a repulsive magnetic field in which magnets of the same polarity are arranged. Magnets 3 of the same polarity are arranged facing an image carrier 1, and a sleeve 2 is placed on the outer periphery of the magnet. In the development area A, the other toner becomes cloud-like. However, in this state, the ears are standing tall (and □ rough).

Figure 2 shows a holding plate 21 inserted as a member for holding down the height of the upstream part K11 of the developing area A.

It became clear that by inserting the presser plate 21, the tall and rough spikes would disappear and the cloud condition would be preserved. Also, the holding plate 21 forms a spike ζ, and the l'! of the image carrier 1 and sleeve 2 is formed. Since the l spacing can be made narrower, a sufficient electrode effect can be obtained. In order to widen the development area as much as possible, it is preferable to insert the ear stand presser member near the center between the magnetic poles of the same polarity and upstream thereof. Moreover, if it is provided upstream from the upstream magnetic pole, this effect will not be obtained. Further, in the developing area, although it is not particularly limited, it is preferable that the direction of gravity is directed toward the sleeve. By doing so, the degree of developer scattering is reduced. In FIG. 2, the magnetic poles 3 are opposed to the development area, but they may be shifted as shown in FIG. 3 so that only the downstream magnetic poles are opposed. In this way, by providing the holding plate 21 on the upstream side ('4%, pJc
As shown in Figure 2, 5 hc does not need to be provided in the narrow development area.
ru. The developer transport speed due to the rotation of the sleeve is gi
! It is preferable that the moving speed be almost the same as or faster than the moving speed of the image carrying member, but in consideration of developer scattering, it is appropriate to keep the moving speed within 4 to 5 times the moving speed of the image carrying member.

The direction of rotation of the slip is preferably the same as the rotation of the image carrier. Image reproducibility is better in the same direction than in the opposite direction.

However, it is not limited to these.

In addition, the thickness of the developer layer formed on the developer transport carrier is adjusted so that the developer that adheres to the developing area is sufficiently scraped off by the thickness regulating blade to form a uniform layer. It is preferable that the thickness be approximately 100 μm to 2000 μm.
is preferred. If the distance between the surfaces of the developer transport carrier and the image carrier becomes too narrow than 10 mm, it will be difficult to form magnetic brush ears that will uniformly develop the area, and it will also be difficult to form sufficient toner particles. cannot be supplied to the developing section (and stable development cannot be carried out).
When the thickness greatly exceeds 2000 μm, the effect of the opposing electrode decreases, making it impossible to obtain a sufficient development density. In this way, if the gap between the developer transport carrier and the image carrier becomes extreme, it becomes impossible to make the thickness of the developer layer on the developer transport carrier appropriate, but if the gap is several □
In the range of 10 μm to 2000 μm, the developer layer can be formed with an appropriate thickness. Therefore, it is necessary to set the gap and the thickness of the developer layer so that the ears of the magnetic brush do not come into contact with the surface of the image carrier under conditions where no oscillating electric field is applied, and are as close as possible to the surface of the image carrier. Particularly preferred. □・It uses magnetic plate 2 to develop latent image toner.
This is because scratches caused by the rubbing of &' and fogging are prevented.

Furthermore, development under an oscillating electric field is achieved by applying an oscillating bias voltage to the sleeve of the developer transport carrier.
Is it preferable? Further, as the bias voltage, it is preferable to use a voltage that is a combination of a DC voltage that prevents toner particles from adhering to non-image areas and an AC voltage that makes it easier for the toner particles to separate from the carrier particles. However, the present invention is not limited to the method of applying an oscillating voltage to the sleeve or the method of applying a superimposed DC and AC voltage.

The uninvented developing method as described above is shown in Figures 4 and 5.
This is implemented by a device such as that illustrated in the figure.

4 and 5, reference numeral 1 denotes a drum-shaped image carrier made of a photoreceptor such as Be that rotates in the direction of the arrow and has a static Irl1 image formed on its surface by a charging exposure device (not shown);
2 is a sleeve made of a non-magnetic material such as aluminum; 3
is provided inside the sleeve 2 and has a plurality of N, 8a on the surface.
! The sleeve 2 and the magnet 3 constitute a silk feeding carrier, which is a fixed magnet body having poles in the circumferential direction. sleeve 2
is rotatable, and the figure shows that the sleeve 2 rotates in the direction of the arrow. Further, the N and S magnetic poles of the magnet body 3, including a magnet of the same polarity disposed opposite the image carrier 1, are normally magnetized to a magnetic flux density of 500 to 1500 Gauss, and the magnetic force causes the surface of the sleeve 2 to A layer of developer material, ie, a magnetic push, as described above is formed. 4 is a regulating blade made of magnetic or non-magnetic material that regulates the height and amount of the magnetic brush in the conveyance process and in the developing area A, and 5 is in the developing area A1! This is a cleaning blade that removes the damaged magnetic brush from the top of the sleeve 2. The surface of the sleeve 2 comes into contact with the developer in the developer reservoir 6, thereby supplying the developer, and the developer 7 stirs the developer in the developer reservoir 6 to uniformly distribute the components. This is a stirring screw. Since the toner particles in the developer tank 6 are erased when development is performed, 8 is a toner hopper for replenishing the toner particles T as described above, 9 is a supply roller having a concave portion on its surface that drops the toner particles T into the developer reservoir 6. A bias power supply 10 applies a bias voltage to the sleeve 2 via a protective resistor 11.

Here, a new ear stand pressing member according to the present invention will be explained. In FIG. 4, a support plate 21 that is a stand-up press member to be inserted into the developing area A has a support member holder fixed thereto, and the press plate 21 supported by the support member 22 has a rotation shaft. On the other hand, this presser plate 4 is provided with an energized tension spring that operates in a clockwise direction to pull up the presser plate 4. It abuts against the positioning member 6 to ensure the positional accuracy of the presser plate 21 in the developing area. (On the other hand, in the apparatus shown in FIG. 5, a support member 32 for supporting the holding plate 311C, which is a member for holding down the ear stand, is fixedly installed, and the holding plate 31 supported by the support member 32 is rotated around a rotating shaft. It is mounted so that it can rotate around the center of rotation.

On the other hand, this holding plate 31 is provided with a biased tension spring U which operates counterclockwise and comes into contact with the positioning member word to hold it down and ensure the positional accuracy of the plate 31 in the current range. ``Here, a high voltage is applied to the developing sleeve 2, so 5. The holding plates 21 and 31 need to be made of an insulating material or kept in a floating state at all times to prevent discharge and leakage. Furthermore, since the presser plates 21 and 31 are made of a hard material, they should also have appropriate elasticity. - As another method of holding the spacer/armpit, a spacer member may be provided on both sides of the tip of the presser plate 21, 31, and a 5V'C may be applied so that the spacer member comes into contact with the sleeve.

In the apparatus described above, when the VC is set so that the surface gap between the sleeve 2 and the image carrier 1 is in the range of several tens to 2000 II x L, and electrostatic development is performed on the image carrier 1, the sleeve 2 The boron brush formed on the surface of the image bearing member 1 is stably maintained in a cloud state by the magnetic body of the same polarity and the brush holding member. The toner particles pass through the toner smoothly, and at that time, a uniform developing effect is imparted to the surface of the image carrier 1, making it possible to stably develop with a high toner density. In order to prevent the occurrence of fogging and to improve the developing effect, a bias voltage having an alternating current component vibrating by a bias voltage R10 is applied to the sleeve 2 between the grounded image carrier 1 and the base 1&. ing. For this bias voltage, as mentioned above, a preferable superimposed voltage of DC voltage and AC voltage is used,
The DC component prevents fogging, and the AC component provides vibration to the magnetic brush to improve the developing effect. Note that, normally, a voltage of 50 to 600 V, which is approximately equal to or higher than the valve surface potential, is used for the DC voltage component, and a voltage of 100 Hz to 10 KH1'', preferably 1 to 5 KH, is used for the AC voltage component.
A voltage with a frequency of z of 100 to rtoo v is used. Note that if the DC voltage component is small and the toner particles contain a magnetic material, the potential may be lower than the non-am potential. If the frequency of the AC voltage component is too low, the effect of imparting vibration will not be achieved, and if it is too high, the developer will not be able to follow the vibrations of the electric field, resulting in a decrease in developer density and the inability to obtain clear, high-quality images. There is a tendency to say. In addition, the voltage value of the AC voltage component is also related to the frequency, but the higher the voltage value, the more effective it will be because it vibrates the magnetic brush (51C), but on the other hand, the higher the voltage value, the more likely it is to cause fogging, which is similar to the phenomenon of lightning strikes. It also makes dielectric breakdown more likely to occur. However, the carrier particles in the developer are insulated by a resin or the like and made spherical to prevent dielectric breakdown, and the occurrence of fog can also be prevented by using the DC voltage component. The sleeve 2 to which this alternating current voltage is applied may have an insulating or semi-insulating coating on its surface with a resin or oxide film.

Although FIG. 4 and FIG. 51ii11 show an example of the developer transport method and the application of an oscillating bias voltage to the developer transport carrier, the developing method of the present invention is not limited thereto. The developing effect can also be improved by applying vibration to the magnetic brush by extending several electrode wires around the developing area between the image carriers and applying a vibrating voltage to them. In that case as well, a direct current bias voltage may be applied to the developer transport carrier, or oscillating voltages of different frequencies may be applied. Further, the method of the present invention can be similarly applied to pressure such as reversal development.

In that case, the DC voltage component is set to a voltage approximately equal to the reception potential in the non-image background portion of the image carrier.

Furthermore, the method of the present invention can be similarly applied to the development of a photoreceptor having an insulating layer and the development of a magnetic latent image.
No. 52, No. 58-187000, No. 58-1870
It can also be applied to coloring in which a toner image is superimposed on a latent image as described in No. 01.

(Example) Fine ferrite particles are dispersed in a resin as carrier particles, and the average particle diameter is 4 μm, and the magnetization is rtru/
I.

Using magnetic particles that have been subjected to thermal spheroidization treatment with a resistivity of 109 scratches or more, and using non-magnetic particles with an average particle size of 5 μm as toner particles, the toner particles are placed in the developer reservoir 6 using the device shown in the figure 4. Development was carried out under conditions such that the ratio of toner particles in the developer in -M was 15% by weight relative to the carrier particles. At this time, a metal plate was coated with an insulating resin on the holding plate 21, and the closest distance from the image carrier 1 to the holding plate 21 was set to 0141EII. The average charge amount of the toner was 3DpC/I.

The conditions for the image carrier 1 in this case are CdS 74@element, its peripheral speed is 180 mV-, the highest potential of the electrostatic image formed on the image carrier 1 is -500 V, and the lowest potential is -100 V.
Met. The outer diameter of the sleeve 2 is also 90 m's, but its rotation speed is 150 r, p, m, the maximum magnetic flux density Gm of the magnetic pole facing the current radius area A of the magnet body 3 is 1200 Gauss, the center part is 800 Gauss, and the developing The thickness of the developer layer before entering the area Arc is OAm, the bias voltage applied to the sleeve 2 is DC voltage component -200■, AC voltage component 2 KHz, 100
It was set as OV. In this embodiment, the distance between the sleeve 2 and the image carrier 1 is 0.7, and the developer layer on the sleeve 2 is not in contact with the surface of the image carrier 1.

The image was developed under the above conditions, transferred to plain paper by corona discharge, and fixed by a heat roller fixing device with a surface temperature of 140°C. The resulting image on the recording paper was free from edge effects and fog. It was a very clear image with high density, and even though we subsequently produced 50,000 sheets of paper, we were able to obtain images that remained stable and unchanged from beginning to end.

(Example 2) 50% by weight of fine ferrite dispersed in a resin as carrier particles has an average particle diameter of I μm and a magnetization of (capital)・mu/I.

Using magnetic particles that have been thermally spheroidized with a resistivity of 10Ω1 or more, and using non-magnetic particles with an average particle size of 5xWL as Tonani particles, development is performed in the developer reservoir 6 using the developing device shown in No. 5m. Development was carried out under conditions such that the ratio of toner particles in the agent to the carrier particles was 15% by weight. At this time, the holding plate 31 was a metal plate coated with resin, and the average charge amount of the toner was set to OJ■ at the position closest to the sleeve 2, and was Iμc/I.

The conditions of the image carrier 1 in this case are the same as in the first embodiment.

The outer diameter of sleeve 2 is also 3 on, but its rotation speed is 100 r.
, p, m-, the maximum magnetic flux density of the magnetic pole relative to development zone A is 1000 Gauss, its center is 400 Gauss, the thickness of the developer layer before entering the development zone O, 611MK, sleeve 2
and image carrier 1 (fill L2tx, that is, 1201)
g, the bias voltage applied to sleeve 2 is DC voltage component -200cm, AC voltage component 4KHz, 2000cm.
It was set to V.

After developing under the above conditions, the image was transferred to plain paper by corona discharge, and then passed through a heat roller fixing device with a surface temperature of 140°C to fix it. It was superior to the liIiiigIt in Example 2 in that it had a high resolution and a high density. successively 5
Although we obtained 10,000 sheets of recording paper, we were able to obtain a stable and unchanging image from beginning to end.

In the above embodiments, if the toner in the two-component developer has magnetism, it goes without saying that magnetic latent particles can be visualized under similar development conditions.

〔Effect of the invention〕

According to the present invention, the method for forming spikes of developer has been improved, and excellent effects can be obtained, such as being able to obtain a clear image without fogging.

[Brief explanation of drawings]

FIG. 1, FIG. 2, and FIG. 3 are detailed explanatory diagrams of the present invention. FIGS. 4 and 5 are partial schematic cross-sectional views showing examples of devices for carrying out the present invention, respectively. DESCRIPTION OF SYMBOLS 1... Image carrier, 2... Sleeve, 3... Magnet, 4... Regulating blade, 5... Cleaning blade, 6... Developer reservoir, 7... Stirring screw, 8・
... Toner hopper, 9... Supply roller, 10...
bias power supply, 11...protective resistor, 21, 31...
・・Pressing plate, ρ, 32・・Supporting member, 23.33・
...Rotation axis, ah, 34...tension spring, 6.35...
・Positioning member, A...Development area, D...Developer,
T...Toner particle, N, 8...Magnetic pole. Representative Yoshimi Kuwabara Figure 1 Figure 2 Figure 3 Figure 4

Claims (5)

[Claims] (1) A two-component developer consisting of toner particles and magnetic carrier particles is supplied onto the developer transporting carrier surface to form a developer layer, and the developer layer on the developer transporting carrier surface is subjected to an oscillating electric field. A developing method for developing a latent image on the surface of an image carrier by forming a repelling magnetic field and providing a holding member. (2) The developing method according to claim 1, wherein the oscillating electric field is formed between the developer transport carrier and the image carrier. (3) The thickness of the developer layer on the developer transporting carrier surface is formed to be □ thinner than between the image carrier surface and the developer transporting carrier. Development method. □ (4) Claims IE1 to 'IIE 31!1F!, wherein the magnetic carrier particles are insulating particles. Development method described. (5) The first aspect of claim 1, wherein a magnetic field is temporally varied in a region where the developer is vibrated by an oscillating electric field.
The developing method described in item 4 of the original image.