JPS63183472A - Developing method - Google Patents

Abstract

PURPOSE:To eliminate ground fogging of an image and to improve a gradation characteristic by allowing a specific toner and a prescribed amt. of magnetic particles to exist in a developing region and oscillating a magnetic brush by alternating electric fields. CONSTITUTION:A toner particle layer and magnetic brush layer are formed on a sleeve 22 and development is executed by impressing a bias electric field consisting of an AC component and DC component between a sleeve 22 and a photosensitive drum 1. The toner 28 is constituted of a nonmagnetic toner (B) consisting of a mixture composed of fine toner powder (A) and fine silicic acid powder. The triboelectric charge quantity TA of the fine powder A and the triboelectric charge quantity TB of the toner B are specified to 1<=TA/TB<=4. The magnetic particles 27 are made to exist at 1.5-30vol.% by the volume of the developing part between the sleeve 22 and the drum 1 so that ears 51 by the particles 27 are formed to a coarse state. The long ears 51 are elongated and contracted by 1,000-3,000Hz electric field generated by a power supply 34 and the short ears 51 are splashed by the same, by which the toner 28 is moved back and forth among the sleeve 22 of the developing part, ears 51 and the drum 1 and is thus transferred to the drum 1.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field] The present invention relates to a developing method for developing a latent image formed by electrophotography, electrostatic recording, or the like.

(Background Art) The applicant has proposed a developing device that forms a thin layer of developer on a developer carrier, brings the thin layer of developer close to a latent image, and develops the image by applying an alternating electric field to this approaching portion. proposed (Special Public Interest Act 1983)
-32375, 58-32377).

This device has a high development efficiency (the ratio of toner that can be consumed for development out of the toner present in the development section) and is very useful in terms of miniaturization.The developer used in this device is one-component magnetic. Since it is a toner, it is essential that the toner contains a magnetic material, and therefore has drawbacks such as poor fixability of developed images and poor reproducibility of color images.

As a device to compensate for this drawback, the applicant has developed a method and device that uses non-magnetic toner to form a thin layer of only non-magnetic toner on a developer carrying member, and forms a latent image of the thin layer of only non-magnetic toner. proposed a developing method and apparatus in which development is carried out by applying an alternating electric field to the two facing each other.
No. 0, specification No. 59-101680).

This is useful because it eliminates the drawbacks caused by the toner containing magnetic materials while retaining the advantages of the developing device using magnetic toner, but it also has the disadvantages of relatively low density of the developed image and the negative effects described below. It has been found that there are some drawbacks in the development characteristics, such as that the image density may decrease as the latent image potential increases.

In addition, what is known as the so-called two-component magnetic brush development method (for example, disclosed in Japanese Patent Laid-Open No. 53-93841) can use a non-magnetic developer, but the consumable toner in the magnetic brush in the development section is Since the ratio of .

[Purpose of the invention]

Therefore, it is an object of the present invention to provide a developing method which can form a developed image with high development efficiency and high image density, and which does not have negative characteristics.

A further object of the present invention is to provide a developing method capable of obtaining good images by showing a toner composition that is most compatible with the present developing method.

[Summary of the invention]

The present invention has a toner particle layer and a magnetic brush layer composed of toner particles and magnetic particles on a developer carrying member, and a bias composed of an alternating current component and a direct current component between the developer carrying member and an electrostatic latent image carrier. In a developing method in which development is performed by applying an electric field, the toner is composed of a particle mixture of at least toner constituent fine powder and silicic acid fine powder, and the triboelectric charge amount T of the toner constituent fine powder and the triboelectric charge of the toner are Quantity T, is 1
The toner is a non-magnetic toner such that ≦T A / T B ≦ 4, and an image is formed between the electrostatic latent image carrier and the developer carrying member in a developing section that supplies toner particles to the electrostatic latent image carrier. The volume occupied by the magnetic particles in the developing area is 1.5% to 30% of the volume of the space created, the electric field of the alternating current component has a frequency of 1000 to 3000H2, and the peak-to-peak voltage is set to the electrostatic potential. Without destroying the image, in the development area, the magnetic particles are exposed to the atmosphere between the developer carrier and the electrostatic latent image.
A developing method characterized in that the toner particles of the toner particle layer on the developer carrying member and the toner particles supported on the surface of the magnetic particles are transferred to the electrostatic latent image carrier in the developing section. Regarding.

The term "nonmagnetic toner" as used herein refers to toner that exhibits magnetization of 10 emμ/g or less in an external magnetic field of 50,000 e and that does not behave substantially as a magnetic toner.

In addition, the toner constituent fine powder referred to here refers to integrated particles obtained by kneading, pulverizing, and classifying raw materials, or polymerizing and granulating them, or melting and dispersing them. This does not include particle mixing of powder with other powders such as fluidity improvers and charge control agents.

The present invention will be explained in more detail based on the accompanying drawings.

FIG. 1 is a sectional view of a developing device according to an embodiment of the present invention.

In this figure, 1 is an electrostatic latent image carrier that carries an electrostatic latent image to be developed, and specifically, it is an endless movable photosensitive drum or belt, or an endless movable photosensitive drum or belt, etc. It is. The method of forming the electrostatic latent image on the second surface is not the subject matter of the present invention, and any known method may be used. In this embodiment, the electrostatic latent image carrier is a photosensitive drum on which an electrostatic latent image is formed by electrophotography, and is rotatable in the direction of arrow a.

The apparatus of this embodiment has a developer container 21. A developing sleeve 22 (hereinafter simply referred to as a sleeve) which is a developer carrying member,
Magnet 23 which is a tin field generating means. A regulating blade 2 that controls the amount of developer conveyed to the developing section on the sleeve 22
4 (hereinafter simply referred to as a plate), and a power source 34 which is an alternating electric field forming means. Each configuration will be explained below.

Container 21 contains a developer having a mixture of magnetic particles 27 and toner particles 28 . In this embodiment, the toner particles and magnetic particles are housed so that the concentration of magnetic particles is high near the sleeve 22 and low at a distance from the sleeve 22, but even if they are housed in the container 21 as a homogeneous mixture. good. The container 21 has an opening at the lower left in FIG.

The sleeve 22 is made of a non-magnetic material such as aluminum, and is provided at the opening of the container 21, with a part of its surface exposed and the other surface protruding into the container 21. The sleeve 22 is rotatably supported about an axis perpendicular to the drawing and is driven to rotate in the direction indicated by the arrow. In this embodiment, the IJ-pipe 22 is a cylindrical sleeve, but
This may be an endless belt.

The sleeve 22 opposes the photosensitive drum 1 with a small gap therebetween and constitutes a developing section. Toner and magnetic particles are conveyed to this developing section by a sleeve 22, and magnetic particles exist here in a volume ratio (1.5 to 30%).

This point will be discussed later.

The magnet 23 is fixed statically inside the sleeve 22 and remains stationary even when the sleeve 22 rotates. The magnet 23 has an N magnetic pole 23a that controls the amount of developer applied onto the sleeve 22 in cooperation with a blade 24, which will be described later, and an S magnetic pole 23 that is a developing Ef1 pole.
b. N for transporting the developer after passing through the developing section into the container 21;
It has a 6n pole 23c and an S magnetic pole 23d. The south pole and north pole may be reversed. This magnet is a permanent magnet in this embodiment, or an electromagnet may be used instead.

The blade 24 can be made of both magnetic and non-magnetic materials, but in this embodiment, at least its tip is made of a non-magnetic material such as aluminum, and the blade 24 is made of a non-magnetic material such as aluminum.
extending in the longitudinal direction of the sleeve 22 near the top of the opening;
Its base is fixed to a container 21, and its distal end is fixed to a sleeve 22.
facing the surface with a gap. The gap between the tip of the blade 24 and the surface of the sleeve 22 is 50 to 500 μm,
Preferably it is 100 to 350 μm, and in this example, 3
00 μm. If this gap is smaller than 50 μm, magnetic particles tend to clog the gap, and if it exceeds 500 μm, a large amount of magnetic particles and toner will pass through the gap, making it impossible to form a developer layer of an appropriate thickness on the sleeve 22. The thickness of the developer layer is smaller than the gap between the photosensitive drum 1 and the sleeve 22 in the developing section, which will be described later (However, the thickness of the developer layer is the thickness on the sleeve 22 when no magnetic force is applied. be). In order to create a developer layer with such a thickness, it is preferable that the gap 11t between the blade tip and the sleeve surface be equal to or smaller than the gap between the sleeve surface and the photosensitive drum surface, but it is also possible to make it larger. .

A magnetic particle circulation limiting member 26 is provided on the inside of the container 21 of the blade 24, and this restricts the circulation area of magnetic particles within the container 21, which will be described later.

The power supply 34 applies a voltage between the photosensitive drum 1 and the sleeve 22 to create an alternating electric field in the gap between them, thereby transferring toner from the developer on the sleeve 22 to the photosensitive drum 1 8.
let The voltage from the power supply 34 may be a symmetrical alternating voltage in which the positive and negative peak voltages are the same, or an asymmetrical alternating voltage in which a DC voltage is superimposed on such an alternating voltage. As a specific voltage value, for example, on an electrostatic latent image with a dark area potential of -600 V and a bright area potential of -200 V, a DC voltage of -300 V is superimposed to increase the peak-to-peak voltage to 500 V.
An alternating voltage of ~2200 Vpp2 and a frequency of 1000 to 3000 Hz is applied to the sleeve 22 side to maintain the photosensitive tram 1 at ground potential.

Next, the operation of the developing device of this embodiment will be explained. First, magnetic particles 27 are put into the container 21 .

The charged magnetic particles are held on the sleeve 22 by the magnetic poles 23a and 23d, and adhere to the entire surface of the sleeve 22 facing inside the container 21, forming a magnetic particle layer. The magnetic particles 27 constitute a magnetic brush in a portion of the magnetic particle layer near the magnetic poles 23a and 23d. Thereafter, toner 28 is put into the container 21 to form a single layer of toner on the outside of the magnetic particle layer. It is preferable that the magnetic particles 27 initially introduced include toner in an amount of 2 to 70% (by weight) based on the magnetic particles, but they may be composed only of magnetic particles. If the magnetic particles 27 are adsorbed and held as a magnetic particle layer on the surface of the -H sleeve 22, no substantial flow or inclination will occur even if the device is vibrated or tilted considerably, and the state in which the magnetic particles 27 cover the surface of the sleeve 22 will not occur. maintained.

Next, when the sleeve 22 is rotated in the direction of the arrow, the magnetic particles rise from the bottom of the container 21 in a direction along the surface of the sleeve 22 and reach the vicinity of the blade 24. Therefore, some of the magnetic particles pass through the gap between the tip of the blade 24 and the surface of the sleeve 22 along with the toner, and the other part collides with the member 26, then reverses and descends by gravity on the outside of the upward path of the magnetic particles. It reaches the lower part of the container 21, rises again near the sleeve 22, and repeats the above operation. Note that some of the magnetic particles 27 rising from the lower part of the container 21 toward the blade 24 turn around and fall before reaching the vicinity of the blade 24. This is particularly noticeable in magnetic particles far from the surface of the sleeve 22.

The magnetic particles that turn around and fall near or in front of the blade 24 take in toner particles from the outer toner layer.

By circulating in this manner with the rotation of the sleeve 22, the toner 28 is mixed with the magnetic particles 27 and the sleeve 22.
Charges up due to friction with the surface.

In the vicinity of this side of the plate 24, the magnetic particles 27 near the surface of the sleeve 22 are attracted to the surface of the sleeve 22 by the magnetic pole 23a, and as the sleeve 22 rotates, the magnetic particles 27 are attracted to the surface of the sleeve 22.
4 and exits the container 21. At this time, the magnetic particles 27 carry away the toner attached to their surfaces. Further, some of the charged toner particles 28 leave the container on the sleeve 22 while remaining attached to the surface of the sleeve 22 due to the reflection force. Blade 24 regulates the amount of developer applied onto sleeve 22.

The developer layer (mixture of magnetic particles 27 and toner 28) thus formed on the surface of the sleeve 22 reaches the developing section facing the photosensitive tram 1 as the sleeve 22 rotates. Here, toner is transferred from the surface of the sleeve 22 and the surface of the magnetic particles onto the latent image by an alternating electric field applied between the photosensitive drum 1 and the sleeve 22, and the latent image is developed.

Next, the behavior of toner and magnetic particles in the developing section will be explained with reference to FIG. In this embodiment, since the electrostatic latent image is composed of negative charges (dark parts of the image), the electric field due to the electrostatic latent image is in the direction indicated by arrow a. Due to mutual friction between the toner particles and the magnetic particles in the developing device and/or the sleeve, the toner particles have a positive charge, and the magnetic particles have a negative charge. Charge is injected into the magnetic particles according to charge/discharge time constants determined by their material, shape, etc., and their charge polarity changes depending on the electric field.

Furthermore, in this embodiment, the photosensitive drum 1 and the sleeve 2 are
2 rotates as shown by the arrow so as to move in the same circumferential direction. The above-mentioned alternating voltage is applied to the space between these by the power supply 34, and an alternating electric field is formed. On the other hand, inside the sleeve 22, there is a magnetic pole 23b of the magnet 23 corresponding to the closest portion between the photosensitive drum 1 and the sleeve 22.

As described above, this space contains the developer, which is a mixture of the magnetic particles 27 and the toner 28, which have been conveyed by the rotation of the sleeve 22. The presence of the magnetic particles 27 here is essentially different from the development method using the so-called one-component non-magnetic developer thin layer (Japanese Patent Laid-Open Nos. 58-143360 and 59-101680). ing. In addition, due to the volume ratio of magnetic particles in this area (described later), the amount of magnetic particles present is much smaller than in the normal so-called magnetic brush development method, and in this respect, it is essentially different from the magnetic brush development method. different. Due to the action of the magnetic pole 23a, this small number of magnetic particles 27 forms the ears 51 connected in a chain in a coarse state, that is, in a sparse state.

The behavior of the magnetic particles 27 in the developing section is special because the degree of freedom is increased.

In other words, these sparse spikes of magnetic particles form a uniform distribution in the direction of the magnetic field lines and can open both the sleeve surface and the magnetic particle surface, so that the toner adhering to the surface of the magnetic particles is not blocked by the spikes. By forming a uniform open surface on the sleeve surface, the toner adhering to the sleeve surface can fly from the sleeve surface to the photosensitive drum surface by an alternating electric field.

Here, the volume ratio of magnetic particles in the developing section will be explained. The "developing section" is a section to which toner is transferred or supplied from the sleeve 22 to the photosensitive drum 1. The "volume ratio" is the percentage of the volume occupied by the magnetic particles present in the developing area relative to the volume of the developing area. As a result of various experiments and considerations, the inventor of the present invention has found that this volume ratio has an important influence in the above-mentioned developing device, and that this
It has been found that a content of 5 to 30%, particularly 2.6 to 26%, is extremely preferable.

If it is less than 1.5%, a decrease in the density of the developed image will be observed, a sleeve ghost will occur, a noticeable difference in density will occur between the area where the ears 51 are present and the area where the ears 51 are not present, and the density on the surface of the sleeve 22 will be This is undesirable in that the thickness of the developer layer formed is non-uniform throughout.

If it exceeds 30%, the degree of closure of the sleeve surface increases and fogging may occur, which is undesirable.

In particular, according to the present invention, the image quality does not monotonically deteriorate or increase as the volume ratio increases or decreases;
Sufficient image density can be obtained in the range of 30%, image quality will deteriorate if it is less than 1.5% or exceeds 30%, and neither sleeve ghost nor fog will occur in the range of the above values where image quality is sufficient. It is based on fact. The former image quality deterioration is thought to be due to negative characteristics, while the latter is caused by the large amount of magnetic particles present, making it impossible to open the sleeve 22 surface, and the amount of toner supplied from the sleeve 22 surface significantly decreasing. Conceivable.

If it is less than 1.5%, the reproducibility of line images is poor and the image quality and density are significantly reduced. On the other hand, if it exceeds 30%, there will be problems with the magnetic particles damaging the photosensitive drum surface and problems with transfer and fixing caused by the magnetic particles adhering as part of the image.

If the presence of magnetic particles is close to 1.5%, partial development unevenness called "roughness" may occur when reproducing a large-area uniform high-density image (solid black) (under special circumstances, etc.). ), it is preferable to set a volume ratio that makes it difficult for these to occur. This value is a more preferable range since the volume ratio of the magnetic particles to the developing area is 2.6% or more. In addition, if the presence of magnetic particles is close to 30%, there may be a delay in toner replenishment from the sleeve surface (such as when the development speed is high) around the area where the ears of magnetic particles come into contact, and scales may appear when solid black is reproduced. There is a possibility that uneven density may occur. As a reliable range for preventing this, it is more preferable that the volume ratio of the magnetic particles is 26% or less.

If the volume ratio is in the range of 1.5 to 30%, sleeve 2
The spikes 51 are formed on the two surfaces in a sparse state to a preferable degree, and the toner on both the sleeve 22 and the spikes 51 is sufficiently exposed to the photosensitive drum 1, and the toner on the sleeve is also transferred by flight due to the alternating electric field. Therefore, almost all the toner is in a state where it can be consumed for development, resulting in high development efficiency (ratio of toner that can be consumed for development out of the toner present in the development section) and high image density.

Preferably, slight but strong vibrations are generated in the ears, thereby loosening the magnetic particles and the toner adhering to the sleeve 22. In any case, it is possible to prevent uneven sweeping and ghost images that occur in the case of magnetic brushes. Furthermore, the vibration of the ears activates the frictional contact between the magnetic particles 27 and the toner 28, thereby improving the frictional charging of the toner 28 and preventing the occurrence of fogging. Note that high developing efficiency is suitable for downsizing of the developing device.

The volume ratio of the magnetic particles 27 existing in the developing section is (M/h)x (t/ρ)X [(C/ (T+
C)]. Here, M is the amount of developer (g/crn') applied per unit area of the sleeve (in the case of non-polishing), and h is the height of the space in the developing area (Cm).
, ρ is the true density of magnetic particles g/cm', C/(T
+C) is the weight percentage of magnetic particles in the developer on the sleeve.

In the developing section defined above, the ratio of toner to magnetic particles is preferably 4 to 40% by weight.

The electrostatic latent image is a dark part, for example, -600V, and the sleeve 22
In the phase in which the positive component of the alternating electric field is applied to the side, the direction of the electric field due to this coincides with the direction of the electric field due to the latent image. At this time, the amount of charge injected into the ears 51 of the magnetic particles by the electric field becomes maximum, and the magnetic particles become positively charged, causing the ears 51
1 is in the maximum standing state as shown in the figure (FIG. 2a), the long spikes extend to the surface of the photosensitive drum 1, and the short spikes fly to the surface of the photosensitive drum 1 due to the action of the electric field.

On the other hand, since the toner is insulating, the charge injection effect is small and it is always positively charged, so the toner on the sleeve 22 and the surface of the magnetic particles is transferred to the photosensitive drum 1 by the electric field formed in this space. At this time, since the ears 51 stand up in a rough state, the surface of the sleeve 22 is exposed, and the toner 28 separates from both the sleeve 22 surface and the surface of the ears 51. In addition, since the ears 51 have charges of the same polarity as the toner 28, the toner 2 on the surface of the ears 51
8 is more likely to move due to electrical repulsion.

In the phase in which the negative component of the alternating voltage component is applied to the sleeve 22, the electric field due to the alternating voltage (arrow b) is in the opposite direction to the electric field due to the electrostatic latent image (arrow a). Therefore, the electric field in this space becomes stronger in the opposite direction, and the positively charged magnetic particles are drawn toward the sleeve 22, causing the long ears to shrink.
The short ears fly to the surface of the sleeve 22.

On the other hand, since the toner 28 on the photosensitive drum 1 is positively charged as described above, it is reversely transferred to the sleeve 22 or the magnetic particles 27 by the electric field formed in this space. In this way, the toner 28 moves back and forth between the photosensitive drum 1 and the surface of the sleeve 22 or the surface of the magnetic particles 27, and as the photosensitive drum 1 and sleeve 22 rotate,
As the space between them increases, the electric field becomes weaker and the developing action is completed.

Conversely, when the electrostatic latent image is bright, for example at -100V, even in the phase where the positive component of the alternating electric field is applied to the sleeve 22 side, there is almost no charge injected into the ears of the magnetic particles by the electric field. As will be described later, the magnetic particles are injected and remain negatively charged during the phase in which a negative component is applied to the sleeve, and the long ears shrink due to the electric field, and the short ears fly toward the surface of the sleeve 22.

The toner is transferred to the photosensitive drum 1 by the electric field formed in this space, but at this time, the ears 51 are shrunk;
The surface of the sleeve 22 is covered to suppress the separation of the toner from the sleeve 22, and in addition, since the ears 51 have charges of opposite polarity to the toner, the toner 28 on the surface of the ears 51 is covered.
suppresses toner separation by electric attraction force.

In the phase in which the negative component of the alternating voltage component is applied to the sleeve 22, the electric field in the direction indicated by the arrow in the opposite direction is at its maximum, the amount of charge injected into the ears of the magnetic particles also increases, and the magnetic particles receive more negative charges. As a result, the ears 51 reach their maximum standing state, with the long ears extending to the surface of the photosensitive drum and the short ears flying toward the surface of the photosensitive drum due to the action of the electric field.

On the other hand, the toner on the photosensitive tram is transferred to the sleeve 22 or the magnetic particles by the electric field formed in this space.

At this time, since the ears 51 are standing up in a rough state, the surface of the sleeve 22 is exposed, making it easier for the toner to return, and since the magnetic particles charged to the opposite polarity to the toner are close to each other, the sleeve 22 is exposed. The toner is further easily separated from the surface of the photoreceptor due to the suction force.

f,+! 51 includes a triboelectric charge or a mirror charge with the toner 28, an electrostatic latent image charge on the photosensitive drum 1, and a charge injected by an alternating electric field between the photosensitive drum 1 and the sleeve 22. varies depending on the charging/discharging time constant of the charge, which is determined by the material of the magnetic particles 27 and other factors.

Generally, the lower the resistance value of the magnetic particles, the more charge is injected, and the magnetic particles are developed in dark and bright areas of the image due to charge injection. On the other hand, when the resistance is extremely high, magnetic particles tend to fog on the background because they always hold a charge with the opposite polarity to that of the toner. Adhesion can be prevented.

In order to ensure the behavior of the magnetic particles described above, the potential of the bias electric field (a combination of alternating current and direct current components) applied between the developing sleeve and the photoreceptor moves the toner from the photoreceptor toward the developing sleeve. The peak value of the waveform component ■, and the dark potential V of the photoreceptor are lvp l>lvo
1, and it is preferable that the electric field due to the alternating voltage exceeds the electric field due to the electrostatic latent image.

As described above, the ears of magnetic particles are brought into a flying state of slight but intense vibration due to the above-mentioned alternating electric field.

By applying an alternating electric field to the developing section in this manner and causing the toner and magnetic particles to vibrate and fly, the following effects are produced.

The development efficiency is extremely high because the toner is ejected from the surface of the magnetic brush and sleeve for development. Therefore, the amount of developer applied is relatively small, and the resolution of the developed image is increased. Furthermore, since the development efficiency is high, it is possible to make the relative speeds of the developing sleeve and the photoreceptor almost the same, and the sweeping of the solid developed area, which occurs when the relative speeds are increased, does not occur.

Furthermore, adding relative speed also has the effect of reducing sweeping.

Also, since the magnetic particles are vibrated by an alternating electric field, 1
There is no trace left by a single magnetic brush, and extremely high-quality developed images can be obtained.

Furthermore, by applying an alternating electric field strong enough to drive the magnetic particles in the space formed between the sleeve and the photoconductor, when the magnetic particles fly as described above, they behave together with the toner in the dark area to promote development, and in the bright area, the toner It exhibits the opposite behavior and has the effect of separating the toner adhering to the surface of the photoreceptor, thereby preventing fogging.

Furthermore, the magnetic particles adhering to the surface of the photoreceptor are eventually pulled back toward the developing sleeve by the magnetic force and the moving force caused by the electric field, thereby reducing the amount of magnetic particles adhering to the photoreceptor.

Furthermore, even when the ears of magnetic particles are unevenly distributed, when the magnetic particles fly, some of the ears collapse and have the effect of smoothing out the magnetic particles.

When using magnetic particles 27 with a relatively low resistance value, the alternating voltage applied between the photosensitive drum 1 and the sleeve 22 is as follows:
The dark part of the latent image during its peak value.

Settings must be made so that no gap discharge occurs in any of the bright areas. On the other hand, when using ears 51 with a relatively high resistance value, it is possible to prevent the gap voltage from reaching the discharge starting voltage by appropriately selecting the frequency of the alternating voltage and the charging/discharging time constant of the ears 51. preferable.

Taking these into consideration, it is preferable that the resistance of the entire f, 1i 51 in the height direction of the spikes 51 is 1015 to 106 Ωcm when the developing brush is in contact with the photosensitive drum 1, and if a developing electrode effect is expected. 1010-106
Approximately Ωcm is preferable.

The average particle size of the magnetic particles 27 is 30 to 100 microns, preferably 40 to 80 microns. In general, the smaller the average particle diameter, the better the triboelectrification characteristics of the toner on the sleeve 22, and sleeve ghost (a phenomenon in which the density decreases due to the rotation of the sleeve immediately after developing a solid black original, or the phenomenon in which the density decreases with each rotation of the sleeve). (which appears as a phenomenon in which the developer density decreases) no longer occurs. However, if the particle size is small, there is a tendency for the magnetic particles to adhere to the electrostatic holder. The position of this adhesion differs depending on the resistance value of the magnetic particles; for example, those with relatively low resistance will adhere to the image area, and those with high resistance will adhere to the non-image area. This is a general tendency, and in reality, the magnetic properties of the magnetic particles, the surface shape, and the surface treatment material (including resin coating) also have some influence.

The developing device shown in FIG. 1 was installed in a PC-10 copying machine manufactured by Canon Inc., and the distance between the photosensitive tram 3 (made of an organic photosensitive material) and the surface of the sleeve 22 was set to 350 μm. The electrostatic latent image has a dark potential of -620V and a bright potential of -180V,
When the DC voltage of the bias power supply was set to -260 cm and the frequency and peak-to-peak voltage of the AC component were changed, development was performed, and a correlation diagram as shown in FIG. 3 was obtained.

If the frequency is less than 1000 Hz, the vibrational flight of the magnetic particles will not be sufficient, and magnetic brush marks will appear on the developed image, which is undesirable. Moreover, if the frequency exceeds 3000 Hz, both the toner and the magnetic particles will not follow the electric field, resulting in an image that is thin and prone to fogging, which is not preferable. The area shaded by vertical lines is the area where discharge is likely to occur between the sleeve and the photoconductor, and this value is even lower in areas with low isobaric pressure at high altitudes. The region shaded with horizontal lines is a region where soil burrs are likely to occur in the background, and the region shaded with diagonal lines is a region where magnetic particles do not fly sufficiently through the gaps. Therefore, it is preferable to perform development in the area surrounded by these lines. Furthermore, in view of image density gradation (fogging, radiation, etc.), the frequency is preferably 1.2 to 2K) lz, Vpp is 8oo to 15o.
The ov area is preferred.

More preferably 1.4 to 1.8 KHz, 1000 to 1
A region of 350 Vpp is good. Similarly, set the S-D interval to 2.
When I changed it to 50-500μm and developed it with the same settings,
The best image was obtained when the alternating electric field listed in Table 1 was applied.

From similar experiments, in practical use the frequency is 1 to 2.2 KHz, V
pp800-2200. S-Dgap250~7007
Very good images were obtained within a range of 7 m. S-
If Dgap is set to 8 ooμm or more, reproduction of fine lines becomes poor even if the alternating electric field voltage is increased, which is not preferable.

Table I S-D spacing and optimum alternating field The particle size of the magnetic particles can be further refined to, for example, an average particle size of 40 μm.
The appropriate range of the alternating electric field changes when the voltage reaches 500 V, and the frequency is approximately the same, but the applied voltage is preferably 500 to 1600 V. This is because as the particle size of the magnetic particles becomes finer, the surface area increases, the amount of charge on the magnetic particles increases, and the magnetic capacity decreases, which reduces the binding force of the fixed magnetic pole inside the sleeve, making the force of the electric field more pronounced. It is thought that this occurs because of receiving. However, small-sized magnetic particles tend to adhere to the photoreceptor, and those with a particle size of 30 μm or less have a commercial 600-90
In a developing device having a 0 Gauss development bn pole, the magnetic particles on the photoreceptor cannot be completely recovered even if an alternating voltage is applied.

As described above, according to this embodiment, development can be performed with high image density and high development efficiency without fogging, ghost images, uneven sweeping, or negative characteristics.

As the material of the sleeve 22, it is possible to use a conductor 9 paper tube made of aluminum, brass, stainless steel, etc., or a cylinder made of synthetic resin. Furthermore, if the surfaces of these cylinders are subjected to conductive treatment or made of a conductive material, they can function as developing electrodes. Furthermore, a core roll may be used and a conductive elastic body, for example, a conductive sponge, may be wrapped around the circumferential surface of the core roll.

Regarding the magnetic pole 23b of the developing section, although in the embodiment the magnetic pole is arranged at the center of the developing section, it may be placed at a position shifted from the center, or the developing section may be arranged between the magnetic poles.

In order to prevent the ghost image phenomenon, the sleeve 2 is not subjected to development from the surface of the sleeve 22 that has returned to the container 21 and has been rotated.
The developer layer remaining on 2 is removed by a scraper means (not shown).
The scraped sleeve surface may be brought into contact with the magnetic particle layer to re-coat the developer.

A mechanism may be provided that detects the concentration of magnetic particles and toner and automatically replenishes toner according to this output.

The developing device of the present invention includes a container 21. It can be used either as a single-use type developer in which the sleeve 22, plate 24, etc. are integrated, or as a regular developer fixed to an image forming apparatus.

As a result of a particularly detailed study on the form of the non-magnetic toner to be applied to the present developing method, the present inventors found that the toner of the present invention is physically hidden by the carrier, unlike the toner used in the conventional two-component magnetic brush method. It is not only carried onto the image, but also flies along the alternating electric field from above the sleeve or magnetic particles, reaches the latent image, and is pulled back from the latent image by the reverse electric field. It was understood that the toner must have a precisely controlled amount of charge and a smooth transition between the sleeve and the latent image due to Coulomb force.

That is, the toner used in the present invention has strong triboelectric charging properties due to the toner constituent fine powder, and ignores physical property or quantitative fluctuations caused by the durability or environment of the externally mixed fluidity improver/charge control agent. They have found that by having a configuration that allows this, the combination with this developing method can produce truly good images. Therefore, it is particularly preferable that the charge amount TA of the fine powder constituting the toner is 20 μC/g or more, and the ratio of the charge amount TI of the toner is 1.2≦TA/TB≦3.

The fine powder constituting the toner of the present invention is produced by containing a conventionally known positively chargeable substance, and in particular contains 1 to 15% by weight of amino/acrylic monomer.
The most preferred is one containing 50% by weight or more of the styrene copolymer because it has a large amount of triboelectric charge. All conventionally known aminoacrylic monomers can be used, but those represented by the following structural formula are generally effective.

CH2=C R3 is hydrogen or a methyl group or an ethyl group R2 is an alkylene group having 1 to 4 carbon atoms R3, R4 is an alkyl group having 1 to 4 carbon atoms The above aminoacrylic-containing styrenic copolymer is contained in a large amount in the toner. This greatly affects the strength, hardness, and even fixing properties of the toner. Therefore, the melt index (
M I ) 0.1~5℃ Glass turning point (Tg) 50℃
It is preferable that it is above.

In addition, all conventionally known monomers can be used as constituent components other than aminoacrylic in the above copolymer, but
In order to adjust the MI value and Tg value to the above conditions, it is generally desirable to contain 70% by weight or more of a vinyl monomer, particularly a styrene-acrylic comonomer. Examples of styrenic monomers include styrene, vinyltoluene, α-methylstyrene, etc., and examples of acrylic monomers include acrylic acid, methyl, ethyl, propyl, butyl, and acrylic acid.
- One or more esters of ethylhexyl, methacrylic acid, esters of methyl, ethyl, propyl, butyl, and 2-ethylhexyl of methacrylic acid, etc. are used.

All conventional methods can be used to polymerize the copolymer of the present invention, but uniform polymerization such as bulk polymerization or solution polymerization can be used.
system is particularly preferred.

The melt index (MI) in the present invention was measured by a manual cutting method using an apparatus described in Shiraki Kogyo Standard Thermoplastic Flow Test Method JIS K7210 at a measurement strength of 125° C. and a load of 2160 g.

Further, the glass transition point (Tg) in the present invention was measured using a Perkin-Nilmer DSC-IB at a heating rate of 5° C./min and a sample of 10 mg.

On the other hand, as the fixing resin for the toner used in the present invention, in addition to the above-mentioned aminoacrylic-containing styrenic resins, monopolymers of styrene and its substituted products such as polystyrene, polyp-chlorostyrene, and polyvinyltoluene, and styrene-p-chlorostyrene may also be used. Polymer, styrene-propylene copolymer, styrene-vinyltoluene copolymer, styrene-vinylnaphthalene copolymer, styrene-methyl acrylate copolymer, styrene-ethyl acrylate copolymer, styrene-butyl acrylate copolymer Polymer, styrene-octyl acrylate copolymer, styrene-methyl methacrylate copolymer, styrene-ethyl methacrylate copolymer, styrene-butyl methacrylate copolymer, styrene-α 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-acrylotril-indene copolymer, styrene-malemethic acid copolymer, styrene-maleic acid ester copolymer Styrenic copolymers such as: polymethyl methacrylate 1 note, polybutyl methacrylate, polyvinyl chloride, 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, chlorinated paraffin, paraffin wax, etc. can be used alone or in combination. Among them, the absolute value of the i.t. amount is one-fifth or less of the above-mentioned aminoacrylic-containing styrenic copolymer.6 Containing 5% by weight or more of a substantially neutral resin means that the toner has an extremely strong positive charge. This is extremely valuable in terms of preventing abnormal overcharging in low-humidity environments, since it has both a weakly charged part and a weakly charged part obtained by diluting it.

The resins listed above can be used as neutral resins whose charge relationship with the aminoacrylic-containing styrenic copolymer is as described above, but polystyrene, styrene-butadiene copolymers, styrene-acrylic copolymers, etc. Polymers, acrylic resins, etc. are preferred. Among these, the styrene-butadiene copolymer is particularly preferred because of its effect in stably retaining a positive charge in the toner.

Any suitable pigment or dye can be used as a colorant in the toner. For example, carbon black, iron black,
Phthalocyanine blue, ultramarine 5 chiticlidone. There are known facial cleansers such as benzidine yellow.

Also, as charge control agents, amino compounds, quaternary ammonium compounds, organic dyes, especially basic dyes and their salts, benzyldimethyl-hexadecyl ammonium chloride 1-decyl-trimethylammonium chloride, nigrosine base, nigrosine hydrochloride, safranin γ
Also, crystal violet, metal-containing dyes, salicylic acid metal-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 for a toner produced by a commonly used mixing-pulverization method, or may be used for a wall material or a core material, or both, of a microcapsule toner.

As for the silicic acid fine powder used in the present invention, one that satisfies the above conditions due to variation in the amount of triboelectric charge caused by mixing with the toner constituent fine powder is used, but it does not disturb the charging of the toner constituent fine powder as much as possible. Since it is desirable that silicic acid fine powder itself has positive chargeability, for example, a coupling treatment with an aminoalkyl silane metal or a treatment with a silicone oil having an amine in the side chain is performed.
Preferably, fine silicic acid powder is used, especially silicic acid fine powder treated with silicone oil having an amine in the side chain.
most preferred from the standpoint of environmental stability).

The fine silicic acid powder used in the present invention is produced by a dry removal method and a wet method. This is a method for producing a powdery substance produced by a dry method and a vapor phase oxidation of a silicon compound. For example, silicon tetrachloride is expressed by the following reaction formula.

S i CIt4 +2H2+02→5i02 +4H
CItAlso, during this process, aluminum chloride or other metals such as titanium chloride, chloride, silicon, etc.
It also includes composite fine powders of silica and other metal oxides, which can be made into four types by being used together with halogen compounds.

Kaya rlIt fine powder produced by dry method (Sh9ka)
There are many commercially available products such as:

AERO3I L (Aerosil)
130 (Japan Aerosil Co., Ltd.)
2000 x 50 TS00 0X80 0X170 0K84 Cab-0-5i 1 (Cab Ozil) M-5CA
BOT Co, (Cabot) MS-7MS-75) (S-5 H-5 Wacker HDK N 20
V 1 5WACKER-CHEMIE GMB
HN 20 E (Wurtzkel Hemie GMBH)
T30D-CFine 5ilica Dow Corning Fransol Fransi
(Francil Co., Ltd.) In addition, there are various conventionally known wet methods. For example, a method of dissolving sodium silicate with acid, ammonia salts or alkali salts, a method of generating an alkaline earth metal silicate from sodium silicate and then decomposing it with an acid, and a method of dissolving sodium silicate with an ion exchange resin. There is a method of converting it into silicic acid.

Commercially available silicic acid i-isomers synthesized by a wet method include the following.

Carplex Shionogi & Co. Nip Seal Nippon Silica Toxeal,
Fine Seal Tokuyama Soda Vita Seal
Takigi Hijiruton, Silnetkus Mizusawa Ihigaku Starsil
Kamishima Chemical Himezil
Ehime Pharmaceutical Thyroid Fuji Davison Ichgaku (Pittsburgh Plate Glass) Manosil Hardman and Ho1den Hoesch Chemische Fabrik Hoesch K
-G (Hiemitsussie Fabrik Herash) Sil
-3tone Stoner
Rubber Co.

(Stoner rubber) Nalco (Nalco) Nalco Chem, Co.

(Narco Chemical) Quso (shoes) Pbiladelphia Quartz Co.

(Philadelphia Quartz) Santocell (Santocell) Monsan
to, Chemical Co.

(Monsanto Chemical) Imsil 111inois Minerals C.

(Illinois Mineral) Calcium 5ilikat (Calcium Silicate) Chemische Fabrik Hoe
sch K-G Calsil Fiillstoff-Gesellschaft M
arquart Fortafil Imperial Chemical In
industries Ltd.

(Imperial Chemical Industries) Mic
local Joseph Cr
osfield &5ons Ltd.

(Jiecef Crossfield & Sump) Ma
nosil Hardman and Ho1den Vulkasil Farben
fabrican Bayer, A.-G.

(Falpenfabriken Bayer) Tufkni
t (tough knit) Durham Chemicals Ltd.

(Doulham Chemicals) Silmos Shiraishi Kogyo Starex Kamishima Kagaku Fricosil
Among the silicic acid fine powders mentioned above, BET
Good results are obtained when the specific surface area measured by nitrogen adsorption is in the range of 30 m2/g or more (particularly from 50 to 4 oom'/g).

As the silicone oil having an amine in the side chain used in the treatment of the silicic acid fine powder, a silicone oil containing a structural unit represented by the formula (I) is generally used.

R.

-31-0-...(1) ■ R3R4 (Here, R1 represents hydrogen, an alkyl group, an aryl group, or an alkoxy group, R7 represents an alkylene group or a phenylene group, R,, R4 represents hydrogen, an alkyl group, or an aryl group. Represents a group, including the above alkyl group, aryl group, alkoxy group, and alkylene group.

The phenylene group may contain an amine, or may have a substituent such as a halogen within a range that does not impair chargeability. ) Among these commercially available products, those represented by the following structural formula are preferably used.

(Here, R+ and Rs represent an alkyl group and an aryl group, R2 represents an alkylene group or a phenylene group, and R3
represents hydrogen, an alkyl group, or an aryl group. i, n is 1
is an integer greater than or equal to ) Specifically, the following are preferred,
Type 1 or Type 2 SF8417 (manufactured by Torrey Silicone) 1200 3500KF393
(Manufactured by Shin-Etsu Chemical Co., Ltd.) 60360KF857
(Manufactured by Shin-Etsu Chemical Co., Ltd.) 70830KF860
(Manufactured by Shin-Etsu Chemical) 250 7600
KF861 (manufactured by Shin-Etsu Chemical) 350
0 2000KF862 (manufactured by Shin-Etsu Chemical) 750 1900KF864
(Manufactured by Shin-Etsu Chemical) 1700 3800KF
865 (manufactured by Shin-Etsu Chemical Co., Ltd.) 90
4400KF369 (manufactured by Shin-Etsu Chemical) 20320KF383 (manufactured by Shin-Etsu Chemical) 20320X-22-3680 (manufactured by Shin-Etsu Chemical)
90 8800X-22-380D
(Manufactured by Shin-Etsu Chemical Co., Ltd.) 2300 3800X-22-3
801C (manufactured by Shin-Etsu Chemical) 3500 3800X-
22-3810B (manufactured by Shin-Etsu Chemical) 1300
1700 The amine equivalent is the equivalent per amine (g/eqiv), which is the value obtained by dividing the molecular weight by the number of amines per molecule.

In the present invention, the amount of silicone oil having an amine in its side chain is 0.2 to 7% of the total amount of the treated silicic acid fine powder.
It is preferable that Q, 0QO be 1 to 10% by weight in the developer. Furthermore, the appropriate processing amount of silicone oil having an amine in the side chain is determined by setting the weight part of this silicone oil to IOO weight parts of the silicic acid fine powder before JA treatment with the above silicone oil to be X, and the silicic acid fine powder used. If the specific surface area of the body is bm'/g and the amine equivalent of the silicone oil having an amine in the side chain is a, then (
11) Particularly good results are given when the relationship in equation 11 is satisfied.

In the above formula, if X>-, the silicone oil having an amine in its side chain will be in large excess relative to the fine silicic acid powder, resulting in problems such as the silicone oil having an amine in its side chain seeping out from the fine silicic acid powder. This makes it difficult to achieve the object of the present invention.

On the other hand, silicone oil with amine in the side chain at 25℃
The viscosity at
0 cps or less is preferable.

If the viscosity is 5,000 cps or more, the silicone oil having an amine in its side chain will not be sufficiently dispersed in the silicic acid fine powder, which may easily cause poor images such as fog.

The treatment of the silicic acid fine powder with a silicone oil having an amine in its side chain can be carried out, for example, as follows. The fine silicic acid powder is vigorously stirred while being heated if necessary, and then the silicone oil having an amine in the side chain or its solution is sprayed or vaporized, or the fine silicic acid powder is slurried. It can be easily treated by adding a silicone oil having an amine in its side chain or a solution thereof while stirring the mixture.

In particular, a method in which a silicone oil having an amine in its side chain or a solution thereof is sprayed or vaporized onto the silicic acid fine powder is a preferred method from the viewpoint of uniformity of treatment.

In addition, from the viewpoint of charging stability of the treated silicic acid fine powder, it is preferable to cure and crosslink the silicone oil having an amine in the side chain on the silicic acid fine powder by heating after the treatment. The best heating temperature is 270 to 350°C. If the temperature is lower than that, the triboelectricity of the treated silicic acid fine powder will decrease, and if it is externally added to the toner, it may not be possible to satisfy the conditions of the present invention. If the temperature is higher than that, the silicone oil will It easily decomposes and becomes unable to be positively charged.

In the present invention, one type or a mixture of two or more types of the above-mentioned silicone oils having amines in their side chains may be used.

In addition, the applied amount of these treated silicic acid fine powders can be set so as to satisfy the above conditions based on the ratio of the amount of frictional electrification between the toner constituent fine powders and the toner, but in general, it is It is effective when added in an amount of 0.01 to 20%, and particularly preferably shows positive chargeability with excellent safety when added in an amount of 0.03 to 3%. The preferred form of addition is 001 to 5% by weight based on the weight of the developer.
It is preferable that the treated silicic acid fine powder be attached to the surface of the toner particles.

In addition, the silicic acid fine powder used in the present invention may be further treated with a conventionally known hydrophobizing agent if necessary, and a known method may be used to react with the silicic acid fine powder or It is applied by chemical treatment with organic silicon compounds that physically adsorb.

Examples of such organosilicon compounds are hexamethyldisilazane, trimethylsilane, trimethylchlorosilane, trimethylethoxysilane, dimethylcyclosilane, methyltrichlorosilane, allyldimethylchlorosilane,
Allyl phenyldichlorosilane, benzyldimethylchlorosilane, bromomethyldimethylchlorosilane, α-chloroethyltrichlorosilane, β-chloroethyltrichlorosilane, chloromethyldimethylchlorosilane, triorganosilylmercaptan, trimethylsilylmercaptan, triorganosilylacrylate, Vinyldimethylacetoxysilane, dimethylethoxysilane, dimethyldimethoxysilane, diphenyljethoxysilane,
Hexamethyldisiloxane, 1,3-divinyltetramethyldisiloxane, 1,3-diphenyltetramethyldisiloxane, and having 2 to 12 siloxane units per molecule, one each for the terminally located unit. dimethylpolysiloxane containing a hydroxyl group bonded to St. These may be used alone or in a mixture of two or more.

Next, a method for measuring the amount of triboelectric charge in the present invention will be described. The surface treatment substances for toner and magnetic particles were pulverized and classified so that they could be considered to have substantially the same particle size.

As for the particle size, the number average is 9 to 11μ1, the volume average is 13 to 15μ, and 6.3μ as measured by Coulter counter.
The number distribution was 5μ or less and the number distribution was 20% or less, and the volume distribution was 20.2μ or more and 15% or less.

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

A metal measuring container 12 with a conductive screen 13 of 400 mesh (the size can be changed as appropriate so that magnetic particles do not pass through) on the bottom is filled with the toner whose triboelectric charge is to be measured or the surface treatment substance for the magnetic particles. , amorphous iron powder with a particle size between 200 and 300 mesh (EFV200/made by Nippon Iron Powder)
About 4 g of a mixture (developer) in a weight ratio of 1:9 (the surface of the 300° surface is untreated and has virtually no triboelectrification like the toner carrier) is put therein, and a metal lid 14 is placed. The weight of the entire measuring container 2 at this time is weighed and is defined as W+(g). Next, in the suction device 11 (at least the portion in contact with the measurement container 2 is an insulator), suction is performed through the suction port 17, and the air volume control valve 16 is adjusted to set the pressure on the vacuum gauge 15 to 70 mmHg. In this state, suction is applied sufficiently (for about 1 minute) to remove the toner or the surface treatment substance of the magnetic particles.

The potential of the electrometer 19 at this time is assumed to be (volt). Here, 18 is a capacitor, and the capacitance is C (μF). Also, weigh the entire measurement container after suction W2 (g)
shall be. This triboelectric charge amount T (μC/g) is calculated as shown in the following formula.

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

The magnetic particles for toner application used in the present invention include, for example, surface-oxidized or unoxidized iron.

Metals such as nickel, cobalt, manganese, chromium, rare earths, and their alloys or oxides can be used. Moreover, there are no special restrictions on the manufacturing method.

It is also possible to coat the surface of the magnetic particles with a resin or the like. As a method for this, any conventionally known method can be applied, such as a method in which a coating material such as a resin is dissolved or suspended in a solvent and applied and adhered to the carrier, or a method in which a powder is simply mixed.

Substances that stick to the carrier surface vary depending on the toner material, but examples include polytetrafluoroethylene, monochlorotrifluoroethylene polymer, polyvinylidene fluoride, silicone resin, polyester resin, metal complex of ditertiary butylsalicylic acid, and styrene resin.・It is appropriate to use acrylic resin, polyacid, polyvinyl butyral, nigrosine, aminoacrylate resin, basic dye and its lake, silica fine powder, alumina fine powder, etc. singly or in combination, but it is not necessarily limited to this. .

The amount of the above compound to be treated may be appropriately determined so that the carrier satisfies the above conditions, but generally the total amount is 0.11 to 30% by weight (preferably 0.5 to 2.0% by weight) based on the carrier of the present invention.
0% by weight) is desirable.

Example Aminoacrylic-containing styrenic copolymers as shown in Table 1, Neutral resin as shown in Table 2, Toner composition fine powder as shown in Table 3, Silicic acid fine powder as shown in Table 4, prepared. It should be noted that all numbers of copies are quantitative.

Example 1 In FIG. 1, the sleeve 22 is an aluminum sleeve with a diameter of 20 mm whose surface has been subjected to amorphous sandblasting using Alundum abrasive grains, and the magnet 23 is a 4Fi
A magnet as shown in FIG. 1 was used in which the N-pole and S-pole were alternately magnetized.

The maximum value of the surface magnetic flux density due to the magnet 23 was about 900 Gauss.

The blade 24 was made of nonmagnetic stainless steel with a thickness of 1.2 mm, and the angle θ was 15°.

Next, 12 parts of toner according to the formulation shown in Table 5 and ferrite particles whose surfaces were coated with styrene-acrylic (particle size 250
-350 mesh) were mixed and applied to the developing device shown in FIG.

The developing device was installed in a PC-10 type copying machine manufactured by Canon Co., Ltd., and a photosensitive tram 3 (made of an organic photosensitive material) and a sleeve 2 were installed.
The distance from the surface of No. 2 was 350 μm. The electrostatic latent image was developed under bias conditions of a dark area potential of -620 V, a light area potential of -180 V, a DC voltage of a bias power source of -260 V, an AC component frequency of 1500 Hz, and a peak voltage of 1200 mm.

Coating thickness on the sleeve 22 surface is approximately 20 to 30 μm
A toner coating layer of 100 to 2 was obtained as an upper layer.
A magnetic particle layer of 00μ was obtained.

The toner is attached to the surface of each magnetic particle.

At this time, the total weight of the magnetic particles and all the toner on the sleeve 22 is approximately 3. O8 x 10-2 g/cm2, and the volume ratio of magnetic particles in the developing area was 15.7%.

In the following examples as well, the volume ratio of magnetic particles in the developing area was adjusted to 10 to 25%.

When an image was produced under the above conditions, a clear image with good gradation without fogging was obtained, and the image reflection density was 1.24.
Met. Furthermore, in order to examine the durability of the developer, a durability test of 10,000 sheets was performed, and a clear image (image density 1.20) without fogging was obtained, similar to the initial image, and toner scattering was also good. On the other hand, a high temperature and high humidity environment (30'C, 90%RH)
), the image density was 1.08.
An image free of problems such as fogging was obtained. Furthermore, clear and fog-free images were obtained even under a low temperature and low humidity environment (10'e, 10%).

Examples 2 to 5 and Comparative Examples 1 to 3 were carried out in the same manner as in Example 1 according to the toner formulations shown in Table 5 below, and all toners that met the conditions of the present invention were found in Table 31 - Toner Composition Fine Powder (J) -(A) 80 parts, (F) 15 parts, lid (K)
-(B) 60 parts, (G) 35 parts, mono (L) -(C
) 75 copies, (H) 20 copies.

(M) - (D) ao part, (F) 15 parts, lid (N
)-(A) 100 copies, lid (0)-(
A) ao part, (1) 20 parts, 1 Table 4 Silicic acid fine powder (P) - Aerosil #130 (9 having a specific surface area of about 13 and having an amine in the side chain) 20 parts by weight was treated in a dark box for 10 minutes. (Q)-RA-200H (manufactured by Nippon Aerosil Co., Ltd. (R)
-R-972 (manufactured by Nippon Aerosil Co., Ltd.) Charge amount (TAuc
/g) 5 parts of Russianine pigment 5 parts of 43.3 azo red pigment 32.4 parts 5 parts
39.80 5 parts cyanine pigment 4.6
0 cyanine pigment 5 parts 47.2 Tsukasa
5 parts 11.10 m2/g, manufactured by Aerosil Co., Ltd.) at a temperature of about 280°C with stirring. Boo - Charged 1st person (Ta,
μ C/g) Example 1 (J) 100 parts, (P)
1.0 part 20.2 Example 2 (J) 100 parts, (Q) o, a part 15.3 Example 3 (K)
100 parts, (P) 0.8 parts 21.1 Example 4
(L) 100 parts, (P) 1.2 parts 15.8 Comparative Example 1 (J) 100 parts, (R) 2 parts
3.5 Comparative Example 2 (M) 100 parts, (P) 1.0 part 12.4 Comparative Example 3 (0) 100 parts, (p)
i, o parts 13.8 Example 5 (N) 100 parts, (P) 1. Part o 28.3TA/TB Evaluation 2, 1 0 2.8 0 Slightly low image density 1.5 0 Slightly low image density at high temperatures 2.5
◎ 12.4 x A lot of fog 0.4 x Image density is low from the beginning Very thin image at high temperatures 0.8 x Thin image with a lot of fog 1.7 0
Slight decrease in image density under low temperature and low humidity [Effects of the Invention] As explained above, according to the present invention, in a developing device that uses magnetic particles with a simple configuration, by interposing a small amount of magnetic particles in the development area, soil power problem can be reduced. It was possible to obtain good image quality with no negative characteristics, good gradation, and no negative characteristics.

Furthermore, by efficiently distributing the toner contributing to development on the sleeve and on the magnetic particles, and performing flying development from both, it was possible to achieve a development efficiency of nearly 100% in an alternating electric field.

This makes it possible to downsize and simplify the configuration of the developing device.

Further, the brush of magnetic particles according to the present invention was brought into contact with the latent image carrier and vibrated by at least an alternating electric field, thereby being able to remove the soil brightener adhering to the latent image carrier.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of a developing device according to an embodiment using the developing method of the present invention. 2(a) and 2(b) are enlarged sectional views of the developing section of the developing device shown in FIG. 1. FIG. FIG. 3 is a diagram showing a developing characteristic curve of a developing device according to an embodiment of the present invention. Further, FIG. 4 is an explanatory diagram of the frictional charge amount measuring device. 1 -----1 latent image carrier (photosensitive drum) 21--1--Developer container (container) 22-----1 developer holding member (sleeve) 23 -
----- 1. Magnetic field generating means (magnet) 27 ----- Magnetic particles 28 ----- 1. Toner particle (toner) 11 -----
- - Suction machine 12 - - Measuring container 13 - - Conductive screen 14 - - Metal lid 15 - - Vacuum gauge 16 - - - - Air flow control valve 17 -------One suction port 18---M-Condenser 19---One electrometer

Claims (1)

[Claims] (1) A toner particle layer and a magnetic brush layer consisting of toner particles and magnetic particles are provided on a developer carrying member, and a bias consisting of an alternating current component and a direct current component is provided between the developer carrying member and the electrostatic latent image carrier. In a developing method that develops by applying an electric field,
The toner is composed of a particle mixture of at least toner constituent fine powder and silicic acid fine powder, and the triboelectric charge amount T_A of the toner constituent fine powder and the triboelectric charge amount T_B of the toner are 1≦T_A/T_B≦4. The non-magnetic toner is a non-magnetic toner that is , the volume occupied by the magnetic particles in the developing area is 1.5% to 30%, the electric field of the alternating current component has a frequency of 1000 to 3000 Hz, the peak-to-peak voltage is set such that the electrostatic latent image is not destroyed, and the developing area is A voltage is applied to move the magnetic particles between the developer carrying member and the electrostatic latent image, and the toner particles in the toner particle layer on the developer carrying member and the toner particles carried on the surface of the magnetic particles are moved in the developing section. A developing method characterized by transferring the electrostatic latent image to the electrostatic latent image carrier.