JPH0387780A - developing device - Google Patents

Abstract

PURPOSE:To always obtain a stable picture by providing the surface of a developer carrier with a conductive rugged surface comprised by binding conductive grains with resin and forming protrusions of the conductive grains on the conductive rugged surface. CONSTITUTION:The surface of the developer carrier 3 possesses the conductive rugged surface formed by binding the conductive grains to the surface with resin, and the protrusions on the rugged surface are formed of the conductive grains. Namely, the surface of the developer carrier 3 is the conductive rugged surface comprised by binding the conductive grains with the resin. Therefore, magnetic grains 7 are carried by the recessed parts formed of resin between the protrusions comprised of the conductive grains and the circulation and agitation of the magnetic grains 7 are activated, moreover, triboelectrification is surely applied to toner grains 8 by rubbing the toner grains 8 on the smooth recessed surface formed of the resin. Thus, a developer thin layer possessing the sufficient quantity of the triboelectrification is stably formed and a preferable picture can be stably obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a dry development type developing device that performs development using toner particles.

[Prior Art] Conventionally, a developing device using a two-component developer has an excellent advantage in terms of stability of copied image quality, but requires sufficient stirring and mixing of the developer. This is to keep the toner concentration constant and charge the toner uniformly and stably.

However, in order to achieve sufficient mixing and agitation, the device configuration was complicated, and the developer, particularly the magnetic particles, was required to have good fluidity.

In order to solve the above-mentioned problems of a developing device using a two-component developer, several developing devices have been proposed in which mechanisms for maintaining toner concentration or mixing and stirring the developer are omitted or simplified.

For example, unlike the conventional two-component development system, the applicant stores magnetic particles and toner particles in a developer supply container,
The present invention provides an apparatus that performs development by supplying only toner particles, which are toner particles, to a developing section.

In this method, magnetic particles are placed in a developer supply container in advance, and the magnetic particles are retained on a developing sleeve, which is a rotationally driven developer carrier, or on a surface portion inside the developer supply container. (first layer), then toner is introduced and stored outside the magnetic particle layer (second layer), and development is carried out (Japanese Patent Laid-Open No. 59-20486
No. 6, Japanese Unexamined Patent Publication No. 59-204867).

In this method, magnetic particles are restrained in a developer supply container, and as the developing sleeve rotates, some of the restrained magnetic particles are circulated on the developing sleeve. Through this circulation, toner particles are attached to the magnetic particles and captured. A thin toner layer was formed in the development sleep J:. This =F method makes it possible to sufficiently mix and stir the magnetic particles and toner particles on the developing sleeve without using a complicated mechanism.

However, when developing is carried out over a long period of time, or when some kind of impact is applied when the developing device is detachable from the main body of the image recording apparatus f=7.

It has been confirmed that the above-mentioned circulation effect becomes unstable, leading to image deterioration.

Therefore, through many experiments, the present applicant has developed a two-component developing device that solves these disadvantages and actively conveys magnetic particles to the developing section in Japanese Patent Laid-Open No. 62-63970 (Showa 60).
(filed on September 17, 2017).

These proposals use alternating electric fields in the developing section to transfer the toner particles on the surface of the developing sleeve to the electrostatic latent image carrier, and the space in the developing section formed by the developing sleeve and the electrostatic latent image carrier is On the other hand, by using a method in which the volume ratio occupied by the magnetic particles transported to the developing section is set to be 1.5 to 30%, development with high concentration and high development efficiency is made possible. That is, by making the spikes of magnetic particles sparse in the development area, allowing the toner particles attached to the surface of the magnetic particles to completely contribute to the development, and also allowing the toner particles attached to the developing sleeve to contribute to the development, high density and This achieved high development efficiency.

[Problems to be Solved by the Invention] However, in the above-mentioned conventional device, when comparing the toner attached to the magnetic particles and the toner attached to the developing sleeve, the amount of electrical charge (hereinafter referred to as It was found that the particles (referred to as tribo) were smaller than those attached to magnetic particles. The reason for this is that as the developing sleeve moves, the magnetic particles are also transported, so there is less chance that the toner particles on the developing sleeve will be rubbed by the magnetic particles. In other words, triboelectric effects due to rubbing against the surface of the developing sleeve were hardly performed. In order to raise the toner mark on the developing sleeve to a predetermined value, it is necessary to have magnetic particles near the developing sleeve that move in a direction opposite to the rotation of the developing sleeve.

However, simply reducing the transportability of the magnetic particles causes problems in consideration of the above-mentioned toner absorption effect by the magnetic particles.

The above-mentioned problem tends to become more noticeable as the particle size of the developer becomes smaller as the quality of copied images becomes higher and the diameter of the developing sleeve becomes smaller as the developing device becomes smaller. In other words, as the diameter of the developing sleeve becomes smaller, the amount of magnetic particles that can be held on the developing sleeve in the developer supply container decreases, and the surface area of the developing sleeve on which toner particles can adhere also becomes smaller, so the unit area on the developing sleeve decreases. The amount of charge on the toner decreases. Furthermore, as the particle size of the developer becomes smaller, it is necessary to perform more sufficient mixing and stirring on the developing sleeve.

Generally, in the above-mentioned developing device, which does not have an automatic toner replenishment device for maintaining toner density (hereinafter referred to as toner content), when a large number of originals with extremely low image ratios are successively copied, the developing device As the toner content in the container gradually increases, the triboelectricity of the toner on the developing sleeve tends to decrease.This is particularly noticeable as the particle size of the developer described above and the diameter of the developing sleeve become smaller.

The fact that the triboelectricity of the toner particles on the development sleeve is lower than that of the magnetic particles t is not a particular problem as long as its absolute value is above a certain value, or if the triboelectricity of the toner particles decreases below a certain value, it will cause problems in the developing area. This may cause problems such as increased toner scattering or scattering when the toner image on the photosensitive drum is transferred to the transfer material. Furthermore, if the triboelectricity of toner particles decreases, there is a possibility that fogging may occur on the image.

Some proposals have been made to try to solve this problem by increasing the regulating force of the developer regulating member, or stress is locally applied to the developer via magnetic particles, causing overcharging and mechanical deterioration of the developer. There was also the problem of making it easier.

The present invention solves the above problems and provides a developing device using magnetic particles and toner particles, which can always produce stable images without using a complicated mixing/stirring mechanism or toner content maintenance device. It is an object of the present invention to provide a developing device that can maintain clear and good images for a long period of time even when using a developer and a small-diameter developing sleeve.

[Means to solve the problem] According to the invention, the above objectives are achieved.

a developer supply container having an opening in the front and containing magnetic particles and toner particles; a developer carrier rotatably disposed in the opening to carry and transport the toner particles and magnetism;
A magnetic field generating means fixedly disposed inside the particles of the developer carrier, and a developer regulating means that comes into contact with the developer carrier to regulate passage of the developer on the developer carrier. In the developing device, the surface of the developer carrier has a conductive rough surface formed by bonding conductive particles to the surface with a resin, and the protrusions of the conductive rough surface or the conductive It is formed by particles.

This is achieved by

[Function] In the present invention, since the surface of the developer carrier is a conductive rough surface in which conductive particles are bonded with a resin, the recesses formed by the resin between the protrusions made of the conductive particles are transports the magnetic particles, and the circulation and stirring of the magnetic particles become active.
In addition, the triboelectric effect on the toner particles is reliably performed by the friction between the toner particles and the smooth concave surfaces formed by the resin.

[Embodiment] Hereinafter, a first embodiment of the present invention will be described based on FIGS. 1 and 2 of the accompanying drawings. This example (the developer used was
-Although it is a component developer, it uses a technique in which magnetic particles are locally present in the developer supply container.

In FIG. 1, l represents a photosensitive drum as a latent image carrier that rotates in the direction of the arrow. The photosensitive drum "C" is a so-called xerographic photosensitive material on which an electrostatic latent image is formed by, for example, the Carlson process, and an insulating layer on the surface on which an electrostatic latent image is formed by the NP process described in Japanese Patent Publication No. 42-2:1910. an insulator with a latent image formed by an electrostatic recording method, an insulator with an electrostatic latent image transferred by a transfer method,
Electrostatic latent image (or potential latent image) by other appropriate methods
Alternatively, it is a member on which a magnetic latent image is formed and retained.

A developing device is disposed opposite to the photosensitive drum l, and the developing device includes a developer supply container (hereinafter simply referred to as a container) 2, a developing sleeve 3 as a developer carrier, and a magnetic field generating device. It includes a magnet 4 as a means and an elastic plate 6 as a developer regulating means.

The container 2 has an opening extending in the longitudinal direction of the developing device (direction perpendicular to the paper surface), and the developing sleeve 3 is inserted into the opening.
or is arranged. The developing sleeve 3 is made of a non-magnetic material such as aluminum.

The developing sleeve 3 is horizontally installed in the opening in FIG. 1, with its right half-circumferential surface protruding into the container 2, and its left half-circumferential surface exposed outside the container 2, and rotatably supported on a bearing. Arrow B
rotationally driven in the direction.

The surface of the developing sleeve 3 is textured as described below.

The magnet 4 is provided inside the developing sleeve 3, and is a fixed permanent magnet in this embodiment, so that even when the developing sleeve 3 is rotated, it maintains a fixed position and posture and generates a fixed magnetic field. do. This magnet 4 has a magnetic pole 5 (N pole).

As the magnet 4, an electromagnet may be provided instead of a permanent magnet.

The elastic blade 6 is provided in contact with the outer surface of the developing sleeve 3. The contact point is located downstream of the position of the magnetic pole 5 of the magnet 4 in the direction of rotation of the developing sleeve 3, and the elastic blade 6 is provided inclined toward the downstream side (that is, opposed to the direction of rotation of the sleeve). The magnet 4 has at least one magnetic pole upstream of the contact point.

Further, a small amount of magnetic particles 7 and ~component developer (hereinafter referred to as toner in this embodiment) 8 are placed inside the container 2, and the magnetic particles 7 are transferred to the container 2 by the action of the magnetic field from the magnet 4.
is constrained on the surface of the magnetic brush, forming a magnetic brush. Here, a small amount refers to the amount of magnetic particles disclosed in Japanese Patent Application Laid-open No. 62-96977, such as a small amount that exists only in the vicinity of the elastic plate with respect to the surface of the developing sleeve at the opening of the developer supply container. More specifically, the amount is such that the surface of the developing sleeve in the vicinity of the elastic plate is hardly covered with magnetic particles and is exposed to the toner. Furthermore, as disclosed in Japanese Patent Laid-Open No. 60-95575, an amount that can cover the entire developing sleeve of the opening IJ portion of the container is included.

In this embodiment, a small amount of magnetic particles is provided in the developer container near the tip of the elastic blade or at the opening of the developer container, and the small amount of magnetic particles is circulated on the developing sleeve to carry the developer. The toner adhering to the body surface or magnetic particles is mixed and stirred, and a thin layer of toner is formed on the surface of the developing sleeve leading to the developing section.

Next, the uneven shape formed on the surface of the developing sleeve 3 will be explained in detail. The present invention improves circulation and vibration of magnetic particles to stabilize toner transport and triboadhesion, and improve development speed! It is intended to cause toner friction by rubbing the toner against the J-Near' surface. However, there is a slight conflict between the circulation/vibration effect of the magnetic particles and the triboelectric effect on the toner directly attached to the surface of the developing sleeve. In other words, if the pitch of the unevenness on the surface of the developing sleeve is increased to increase the roughness of the uneven surface in an attempt to improve the circulation and vibration of the magnetic particles, the conveying force of the magnetic particles on the developing sleeve will be improved and the circulation and vibration will be improved. The vibration effect becomes more intense. Therefore, the triboelectricity imparted to the toner by the magnetic particles is improved.

However, if the pitch of the unevenness is increased, not only the magnetic particles but also the toner conveying force is improved, and the chance of obtaining tribo due to the toner staying near the developing sleeve and repeatedly rubbing against the surface of the developing sleeve is reduced. therefore,
The triboelectricity applied to the toner from the surface of the developing sleeve tends to decrease, and the triboelectric value Q/M of the toner on the developing sleeve decreases.
(the amount of electric charge per unit weight) will show a decrease.

On the other hand, if the pitch of the unevenness on the surface of the developing sleeve is made small and the surface is made smooth so that the toner in the developing sleeve sufficiently rubs against the surface of the developing sleeve, the tribo value Q/M of the toner on the developing sleeve will be high. Otherwise, the transportability of the magnetic particles deteriorates, and the circulation/vibration effect decreases. Therefore, the triboading of the toner by the magnetic particles and the transport of the toner by the magnetic particles are reduced.

The present invention provides a developing sleeve that maintains a balance between the circulation and vibration of the magnetic particles and the rubbing action of the toner on the surface of the developing sleeve, and is capable of always producing stable images.

In the present invention, conductive particles that can form a convex portion by themselves are used to form a rough surface, and a resin for binding these particles is used to form a concave portion to form a smooth surface. In order to maintain the conductivity of the surface layer as a whole, highly fine conductive powder was mixed in the resin so as not to affect the uneven structure of the surface. By doing this, the toner is captured and rubbed on the smooth surface of the recess, so the frequency of rubbing between the developing sleeve and the toner increases, which improves the ability of the developing sleeve surface to provide tribo. In addition, since the transportability of the magnetic particles is improved by capturing them in the recesses, it is possible to improve the circulation and vibration effects of the magnetic particles.

The resistance value of the surface of the developing sleeve as described above is set to 104 Ω in order to prevent the accumulation of electric charge on the surface of the developing sleeve and to achieve good developing performance in non-contact development.
It is preferable to keep it below C-.

Further, as the resin used in the developing sleeve, a material having a triboelectrification series different from that of the toner may be used in order to improve the triboelectricity imparting ability of the toner. For example, in order to easily charge the toner positively, a resin with strong electron-attracting properties such as a fluororesin, a vinyl chloride resin, a polyolefin resin, a 5-chlorostyrene resin, or an epoxy resin may be used.

On the other hand, to make it easier to charge negatively, use polyamide resin,
It is preferable to use resins with strong electron-donating properties such as melamine resins, polyurethane resins, and acrylic resins.

Similarly, the binder resin may be impregnated with a charge control agent for toner. Furthermore, lubricating powder may be dispersed in the resin layer to facilitate peeling off and separation of the toner on the developing sleeve.

Next, as for the surface roughness (Rz) of the unevenness of the developing sleeve 3, the height of the protrusion is Rz, which is 0.0 of the average particle diameter of the magnetic particles.
The average pitch pressure fid of the convex portions is preferably 0.02 to 5 times the average particle diameter, and preferably a range satisfying h<2d.

Here, the surface roughness Rz is defined as the straight line that passes through the third peak from the highest of the convex portions and the third valley from the deepest of the concave portions among the straight lines parallel to the average line of the portion of the surface extracted by the standard length. This interval is selected and represents the JIS surface roughness ■60
This is based on the 1st standard. The same applies to the surface roughness Rz below.

Outside the above range, the magnetic particles will not be able to circulate and vibrate, resulting in insufficient mixing and stirring with the toner. In particular, when the upper limit is exceeded, the conveying force on the surface of the developing sleeve becomes too strong, making it difficult to restrain the magnetic particles in the developer supply container.

It is also desirable that the conductive powder be larger than the 5 liters used as the 2 conductive powder. Below 5 wells, the transportability of the magnetic particles tends to decrease, and the stirring and vibration effects of the magnetic particles tend to decrease.

The conductive powder to be mixed in the resin may be flaky, ta
Metal objects in various shapes in the form of fibrous powder, metal oxide particles, graphite, carbon fluff, etc. can be used.

Next, the operation of the apparatus of this embodiment will be explained. When the developing sleeve 3 rotates in the direction of arrow B, the magnetic particles 7 are conveyed in the rotational direction of the developing sleeve 3 while being restrained by the magnetic field formed by the magnet 4.

However, the magnetic particles 7 are prevented from being transported by the ends of the elastic blades 6 and are allowed to exit the container 2, and fall toward the vicinity of the magnetic poles 5 due to gravity and magnetic force.

At this time, the magnetic particles 7 circulate near the end face of the elastic plate 6 and vibrate near the magnetic pole 5. This vibration becomes more intense as the amount of magnetic particles is smaller and depends on the conveying force of the developing sleeve 3, the reversing force of the elastic blade 6, the pullback force of the magnetic force, and the pullback force of gravity. On the other hand, the toner 8 mixed between the magnetic particles 7 enters the contact portion between the elastic blade 6 and the developing sleeve 3 and is conveyed on the surface of the developing sleeve 3 to the outside of the container. As the magnetic particles 7 circulate and vibrate on the developing sleeve 3,
Inside the container 2, the toner 8 is stirred and at the same time the magnetic particles 7
The developing sleeve 3 receives frictional electrification due to the sliding friction therebetween and also due to the sliding friction in the recess formed on the surface of the developing sleeve 3 . Furthermore, the toner 8 is distributed between the elastic blade 6 and the developing sleeve 3.
When passing through the contact area with the developing sleeve 3, the developing sleeve 3 is rubbed against the surface of the developing sleeve 3 by the elastic blade 6, and is further subjected to frictional electrification. In this way, the toner 8 can receive sufficient triboelectric charging. As a result, image density can be ensured in the developed image, and background fog can be further reduced.

The toner 8, which has been sufficiently triboelectrically charged in this manner, passes through the contact portion and the toner S on the developing sleeve 3! It is formed as a layer and transported on the developing sleeve 3 to the developing section facing the photosensitive drum l. In the developing section, the toner in the - section is consumed by the developing operation, and the other toner is collected by the lower part of the developing sleeve 3 as the developing sleeve 3 rotates. A sealing member 9 is provided in this recovery portion to allow the toner that has not been consumed during development to pass into the container 2, and to prevent the magnetic particles 7 and toner 8 in the container 2 from leaking out from the bottom of the container 2. To prevent. The collected toner on the sleeve 3 is first scraped off by the circulation and vibration of the magnetic particles 7, and then stirred and mixed by the 1-meter particles 7, and then applied again to the surface of the developing sleeve 3 as a thin toner layer. In this way, the toner that is not consumed during development is once scraped off from the surface of the developing sleeve 3, so regardless of the variation in the amount of residual toner on the surface of the developing sleeve 3 after development, the surface after passing through the contact area 2, a thin toner layer of uniform thickness is formed. Further, since the toner is once scraped off in this manner, the toner on the sleeve 3 is replaced, thereby preventing excessive charging of the toner, that is, charge-up.

The developing method in this embodiment is, for example, the method described in Japanese Patent Publication No. 58-12375, in which a minute gap is provided between the photosensitive tram 1 and the developing sleeve 3, and a direct current is superimposed between them. Although it is possible to use a method of applying a voltage to transfer the thin layer of toner on the developing sleeve 3 to the electrostatic latent image on the photosensitive drum 7 in an imagewise manner, there are other methods.
Contact development method can also be used.

Next, an example of an experiment conducted based on this example will be explained.

In this experimental example, an aluminum developing sleeve with a diameter of 16 mm was used, and carbon powder as conductive particles forming the convex portion and crystalline graphite particles as conductive powder mixed in the resin (short axis 5 μ, -1 long sleeve lug) were used. ) and 1=9
A mixture of these and a phenol resin in equal amounts was applied to the surface of the developing sleeve and dried.

The development sleep described above is based on the average distance f between graphite particles of about 1511. Kago, resin layer thickness on developing sleeve 6μm
, Rz#2.6)Lm, and the electrical resistance value of the entire layer was about 10Ωcll.

In this experimental example, the content of graphite is preferably 10 to 60% in terms of overlap percentage, and the content of carbon powder is preferably 0 to 40%, and the total content of these powders is preferably 10 to 60%.

Next, as a material for the elastic blade 6, for example, rubber with a 11S hardness of 40 to 80@, preferably 50 to 70", is suitable for stably forming a thin toner layer. In this experimental example, silicone rubber (rubber hardness JIS 60' thickness 21111
1) The end of the elastic blade 6 is connected to the developing sleeve 3.
is urged to come into contact with. Note that the blade end herein refers to the tip of the plate, the vicinity including the tip, or the vicinity of the tip not including the tip.

If the edge of the tip of the elastic blade 6 is too far away from the surface of the developing sleeve 3, the magnetic particles 7 may enter this gap, causing
This is because it has been found that this may impair the uniformity of contact pressure and may damage the surface of the developing sleeve 3.

The elastic blade setting pressure is 5 to 200 g/c+*
(Linear pressure in the generatrix direction of the developing sleeve) is effective, and in the experimental example, it was set to 40 g/cm.

As the magnet 4, one with a peak value of magnetic flux density of 700 Gauss and a half value @J60° was used.

As the magnetic particles "f-7", iron powder, ferrite powder, etc. can be used.Furthermore, it is more preferable that these are coated with a resin in accordance with the charging polarity of the developer 8.The particle size of the magnetic particles 7 is 40 to 300 μa can be used. If it is less than 40 pm, the fluidity of the magnetic particles 7 is poor;
It was confirmed that sufficient circulation and vibration were not obtained, the possibility of toner 8 being taken in was reduced, and a stable thin layer of toner 8 was not formed. If the particle size is 300← or more, the toner 8 can be sufficiently supplied, but the frictional electrification is not sufficient, which is not preferable. Within this range,
70-200 gm is particularly preferred in order to obtain sufficient circulation and vibration of the magnetic particles 7. In this example, the particle size is 80~
100 JL En (150/200 mesh) iron particles (maximum magnetization = 190 emu/g) coated with acrylic and fluorine resin were used.

The toner is a layer of toner powder with an average particle size of 8μ, consisting of 100 parts of a copolymer of styrene/acrylic resin and styrene-butadiene resin and 5 parts of berylene red pigment, with 1.0% colloidal silica added externally. Red toner was used.

The above device was installed in a Canon FC5 copying machine, and a frequency of 1800 i1z was used as a bias source.
, -28 to an AC voltage with a peak-to-peak voltage of 1200V
Using a superimposed 0V direct current, the photosensitive drum l,
The surface potential of the latent image of h is -520V in the dark area and -200V in the bright area.
and set the distance between the developing sleeve 3 and the photosensitive drum 1 to 250 mm.
Development was carried out by non-contact development at a setting of gm.

As a result, a uniform coating layer of about 25 wells was obtained on the developing sleeve, and when the amount of charge on this layer was measured by the flow-off method, the amount of charge was +14)Lc/g. This amount of charge is sufficient to obtain a good image.

Moreover, the obtained image was a good red image with a reflection density of 1.3.

Further, when images were continuously formed on 2000 sheets, good images without sleeve ghosts could be obtained up to the final image formation.

Next, we will discuss a comparative example that was compared with this example.
I do it. In this comparative example, the surface of the aluminum developing sleeve was coated with particle size #400 (the particle size standard is JIS R6
001 abrasive material. The same applies to the particle size below. ) to spray silicon carbide with a diameter of 7 cm using a nozzle, at a distance of 90 cm with an air pressure of 4 kg/cii'.
It was roughened for a second and then sandblasted using so-called amorphous abrasive grains of RZ"; 1.8 pm.

In this comparative example, slight background fogging occurred during a durability test under a low humidity environment. This is because the developing sleeve of this comparative example is a rough sleeve with an RZξ of 1.8 g, and has a R
This is because although Z was small, the amount of toner applied per unit area M/S (g/C112) was large, and the amount of developer tribosure per unit heavy breakage Q/M (cou 1 part g) was small. That is, it is thought that the roughened surface treated with amorphous particles such as silicon carbide has a sharp rough surface, so the conveying force is stronger and the amount of coating is larger. Therefore, it is considered that the tribo value also became smaller.

In addition, when carrying out a durability test on zoooo sheets and using the developing sleeve of the experimental example, although the surface of the developing sleeve was slightly worn due to magnetic particles, etc., RZ#2
．． Although the unevenness was rather large, the triboelectric value of the toner was slightly decreased, and the coating amount was slightly increased, a good image was obtained. The slight increase in RZ is considered to indicate that even when the surface of the developing sleeve is worn, large conductive powder or the like protrudes from the surface and the unevenness is maintained within a predetermined range. On the other hand, in the developing sleeve of the above comparative example, RZ"=-1.6μ
m, the tribo value increased, the coating amount decreased, and developing sleeve ghosts were more likely to occur. Although this was not a large change in terms of roughness, when observing the surface of the developing sleeve under a microscope, it was found that the tips of the sharp convex parts had been worn out and smoothed out, and this may have been the cause. This is considered to have occurred. This phenomenon further causes a deterioration in the durability of S in durability tests in a low humidity environment f. Under such circumstances, as the durability progresses, the triboelectricity is applied too strongly, causing overcharging of the toner on the surface of the developing sleeve, resulting in low image density and reverse fogging.

In addition, in the present invention, a new surface is constantly exposed due to moderate overall abrasion in which the unevenness is maintained within a certain range even during durability, which also prevents contamination of the developing sleeve.

Furthermore, in the experimental example E, an example was shown in which an elastic rubber blade was used as a member for regulating the developer, but a metal elastic blade may also be used. Also, JP-A-60-95
It is also preferable to use a magnetic plate that does not come into contact with the developing sleeve as disclosed in No. 575 from the viewpoint of wear on the surface of the developing sleeve. Furthermore, in order to effectively take advantage of the characteristics of both,
Particular preference is given to using elastic rubber blades impregnated with granules.

Although non-magnetic toner was used in the above experimental example, magnetic toner can also be used as long as it has weaker magnetism than magnetic particles and can be triboelectrically charged.

Furthermore, the number of magnetic poles of the magnet 4 inside the developing sleeve 3 is further increased, and a magnetic pole is also provided on the photosensitive tram 1 side, thereby transporting the small amount of magnetic particles that have passed under the elastic blade 6 as the developing sleeve 3 rotates. It may be collected into the developing sleeve 3.

Next, a second embodiment of the present invention will be explained based on FIG.

The device of this embodiment changes the setting method of the developer regulating means, and
This example differs from the previous example in that a two-component developer is used.

It is preferable for the uneven surface of the developing sleeve to satisfy the numerical range relationship of the height h and the distance d described above in order to facilitate circulation and vibration of the magnetic particles. This is because if it is outside the above range, the amount of replenishment toner taken into the magnetic particle layer will vary, making it impossible to obtain an appropriate toner concentration of the developer applied onto the developing sleeve.

In this embodiment, the two-component developer is composed of magnetic particles 7 made of ferrite having a particle size of approximately 70 to 50 mm and whose surfaces are coated with silicone resin, and 0 parts of styrene-tutadiene copolymer resin. , a small particle size toner 8 powder with an average particle size of about 71 Ll, which is made of 5 parts of copper phthalocyanine pigment, is mixed with a non-magnetic toner made by adding 1.2% of colloidal silica.

The developing sleeve 3 is shaped as a cylinder with an outer diameter of approximately 6-20 m and a wall thickness of approximately 0.75 s+s, or preferably has an outer diameter of approximately 8-16 mm to prevent the developer 12 from scattering, etc. You may take measures to sufficiently prevent this.

An alternating electric field is formed in this developing sleeve 3 during development. Further, a magnet 4 as a magnetic field generating means built in the developing sleeve 3 has magnetic poles N and S set as a pair on the outer surface C, and the center of rotation of the magnetic poles N and S and the developing sleeve 3 is on a straight line. If you set them so that they are lined up, you can make them appear in a variety of ways. That is, the magnet 4 can be an integrally molded magnet consisting of only magnetic poles N and S, a magnet made by bonding two magnets together with the different polarities on the outside, or a magnet 4 with two notches provided in the supporting member to insert the different polarities therein. It is possible to create a magnet by conventionally known means, in which two magnets are respectively embedded so that the magnets are on the outer surface. In short, it is sufficient that 61 poles N and 61 magnetic poles S are set on the outer surface. The distance from the outer circumferential surface of the magnet 4 to the outer circumferential surface of the developing sleeve 3 is 1.25 mm, L/ Therefore, since the thickness of the developing sleeve 3 is 0.75 m5, the outer circumferential surface of the magnet 4 and the inner circumferential surface of the developing sleeve 3 are The gap between the two is approximately 0-5!
*ll, and the developing sleeve 3 is rotatable in the direction of arrow B. One magnetic pole N of this magnet 4 is set at a position on the opposite side of the developing area P on the extension line xY of the straight line connecting the rotation center OI of the photosensitive drum 1 and the rotation center 02 of the developing sleeve 3. Further, the other magnetic pole S is set at a position facing the development area P on the straight line. In this way, the magnetic poles N and S are set, and the magnet 4 is formed so that its magnetic force can be exerted as effectively as possible on the outer circumferential surface of the developing sleeve 3.

In the apparatus of this embodiment, for example, about -2
A WI image potential of 00v to -700V is formed, and the development area P
is the set gap 400 I between the photosensitive drum 1 and the developing sleeve 3
Lm, the voltage between the peak values of the waveform on the developing sleeve 3 is about tsoov, and the AC voltage with a frequency of 1600 Hz is -25
For example, under the condition that a DC voltage of 0 V is applied in a superimposed manner to form a layer thickness of about 701 L11 to 80 Ien of developer on the outer peripheral surface of the developing sleeve 3, the outer diameter of the developing sleeve 3 is reduced to about 1.
0 am, a non-magnetic plate is used as the developer regulating means 6, and the gap between the non-magnetic plate and the developing sleeve 3 is set to 30 am.
When developing is performed under the condition that the magnetic force of the magnet 4 acting on the outer circumferential surface of the developing sleeve 3 is set to 800 Gauss, the magnetic force of the bipolar magnet 4 is
The developer acts strongly on the outer circumferential surface of the developing sleeve 3, and the magnetic brush of the developer reaches a long distance. In other words, a sufficient number of magnetic brushes face the photosensitive drum 1, and development efficiency is improved. Moreover, since the developing sleeve 3 is miniaturized, the developer is sufficiently transported to the developing area P. Therefore, a high-quality image with sufficiently high image density can be obtained. Furthermore, since the developing sleeve 3 is miniaturized, the developing area P is limited to the area closest to the photosensitive drum, so that a good image with high gradation can be obtained.

Furthermore, the developer coating layer is made uniform by the surface of the developing sleeve of the present invention. In particular, as in this embodiment, when a toner with a small particle size is used, which tends to be non-uniform in terms of triboelectricity, and a small-diameter sleeve and a dipole magnet are used, the number of times the developing sleeve contacts the developer is reduced. Nevertheless, by forming the conductive uneven layer according to the present invention on the surface of the developing sleeve, it is possible to improve the triboelectric effect on the toner, and to obtain good image quality without background fog.

In addition, in order to develop the same area on the photosensitive drum with a small diameter sleeve, it was necessary to increase the operating rotation speed compared to a large diameter sleeve, but the small diameter sleeve of this example has good performance even after long-term use. Stable image quality was obtained.

Further, in this embodiment, a case where the present invention is applied to a toner with a small particle diameter of about 5 to 10 μm is shown, but it can also be applied to a toner of about 0 to 20 gm used in a normal copying machine.

Further, in the apparatus of the above embodiment, the developer regulating means 6 uses a non-contact type non-magnetic blade and a magnetic plate, but is not limited to these. It is also possible to use an elastic blade of the type that comes into contact with the developing sleeve. In this case, the contact portion of the developer regulating means means the tip of a non-contact type plate. In addition, the third embodiment shown in Fig. 3! The AIILL is equipped with a supply roller 15 made of elastic sponge, which supplies the developer to the developing sleeve 3 and peels off the developer on the developing sleeve 3.

In addition, although the case has been shown in which non-magnetic toner is taken in by the movement of magnetic particles attached to the developing sleeve 3, and the magnetic particles and non-magnetic toner are mixed and stirred on the developing sleeve 3,
The present invention is also applicable to a normal two-component developing system (mixed developer of weakly magnetic toner or non-magnetic toner mixed with FB carrier) (Japanese Patent Application No. 50-204605).

In addition, the surface of the developing sleeve can be prepared by mixing conductive powder and binder resin directly on the almost smooth surface of the metal sleeve.
It is preferable to form a rough surface in advance and then apply a mixed solution of conductive powder and a binder resin. In particular, it is preferable to form a rough surface in advance and then apply the above coating after sandblasting using regular abrasive grains such as granular particles. It has been found that the sleeve further improves developer conveyance and triboelectric properties. In addition, a filling agent may be mixed, for example, silicon carbide 5iC grown as a needle-shaped single crystal (minor axis 0.1-1, υμ size, long sleeve 50-200cm).
gm) to improve mechanical strength. In this case, the developing sleeve can be constructed only from the resin agent mixed with conductive powder, and a developing sleeve that is lightweight, highly elastic, and difficult to deform can be obtained.

[Effects of the Invention] As explained above, according to the present invention, a thin developer layer having a uniform one-component or two-component developer layer thickness and a uniform and sufficient amount of tribo is stably formed. By using this thin layer of developer for the developing operation, it is possible to give more leeway to the setting conditions of the developer and the developing device! f images can be stably obtained. In particular, even when a small particle size developer is used or a small diameter developing sleeve is used, a good image can be obtained by preventing the toner from being over or under charged.

Further, according to the present invention, when mixing and stirring the two-component developer on the developing sleeve, it is possible to not only improve the circulation and vibration of magnetic particles on the developing sleeve, but also to charge the toner on the developing sleeve. It is possible to try to stabilize the situation. For this reason,
It can be applied to non-contact development that requires uniform stabilization of the tribo value, and it can also be applied to multicolor electrophotographic processes in which various toners are layered on a photosensitive drum for development, resulting in a good screen without color mixture. .

Further, even when Ia magnetic particles are used, there is little wear caused by the magnetic particles and it is possible to overcome uneven shapes.

Furthermore, when developing the same area on the photosensitive drum, a small-diameter sleeve requires a higher operating rotation speed than a large-diameter sleeve.
According to the present invention, this point could also be improved, since it required a surface structure with high wear resistance.

Furthermore, the functional burden on members other than the developing sleeve that contribute to charging toner, such as elastic blades and magnetic particles, can be reduced, and the selection and setting conditions of these members can be expanded.

[Brief explanation of drawings]

FIG. 1 is a sectional view showing a schematic configuration of a first embodiment of the present invention;
FIG. 2 is a sectional view 2 showing a schematic configuration of a second embodiment of the present invention.
FIG. 3 is a sectional view showing a schematic configuration of a third embodiment of the present invention. 2...Developer supply container (container) 3...
Developer carrying member (developing sleeve) 4... Magnetic field generating means (magnet) 6... Developer regulating means (elastic blade) 7...
...Magnetic particle 8...Toner particle (toner)

Claims (3)

[Claims] (1) A developer supply container having an opening in the front and containing magnetic particles and toner particles, and a developer carrier rotatably disposed in the opening to carry and transport the toner particles and magnetic particles. , comprising a magnetic field generating means fixedly disposed inside the developer carrier, and a developer regulating means that comes into contact with the developer carrier to regulate passage of the developer on the developer carrier. In the developing device, the surface of the developer carrier has a conductive rough surface formed by bonding conductive particles to the surface with a resin, and the protrusions on the conductive rough surface form the conductive particles. A developing device characterized by being formed of particles. (2) The developing device according to claim 1, wherein the surface of the recess formed between the protrusions is smoother than that of the protrusions. (3) The surface of the developer carrier has a resistivity of 10,000 ohms.
centimeter or less, the height of the protrusions is 0.02 to 1 times the average particle diameter of the magnetic particles, the average distance d between the pitches of the protrusions is 0.02 to 5 times the above average particle diameter, and from the above h. 2. The developing device according to claim 1, wherein d is larger than d.