JPS6275679A - Developing device - Google Patents

Abstract

PURPOSE:To improve the image quality and to prevent dirt in the periphery of a device by controlling the supply quantity of magnetic particles and that of toner particles so that a toner particle layer is formed on the surface of a photosensitive drum released with bristled magnetic particles. CONSTITUTION:A voltage is applied between a photosensitive drum 1 and a sleeve 2 by a power source 34 to form an alternating electric field in the gap between them, and toner particles 28 are transferred to the drum 1 from a developer on the sleeve 2. The supply quantity of particles 27 and 28 to the drum 1 is controlled by a blade 6 so that the surface of the drum 1 is released with magnetic particles 27 bristled on the drum 1 and a layer of particles 28 is formed on the released surface. A developing vessel 4 which has the blade 6 and the drum 1 in an aperture part and contains particles 27 and 28 is provided, and the lower part of the vessel 4 is extended in the direction of the drum 1 to prevent the developer from leaking to the outside. A 'Mylar(R)' sheet member 11 is provided to close the gap between the sleeve 2 and the entrance of the vessel 4, and penetration of recovered particles 27 and 28 is permitted by the energizing force of the member 11.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Application of Jlf, Industry) The present invention relates to a developing device that performs development by applying toner particles to an object to be developed such as an electrostatic image bearing member, and relates to an electrophotographic device. It is applicable to general recording devices such as static recording devices and printers.

(Background technology) In recent years, the field of electrophotography has become lighter, thinner, and smaller.
The miniaturization of photographic devices is progressing.

Also, in such a small electrophotographic device.

In order to facilitate maintenance, there are some that integrate the process unit 14 such as the photoreceptor, developing device, and cleaner into a cartridge.

Another recent trend in electrophotography is colorization. That is, some devices are capable of producing a single color by replacing the above-mentioned process unit or developing device, and attempts are also being made to produce two colors (for example, black and red).

Under these circumstances, there are increasing opportunities for users to manually take in and out the process unit that includes the developing device, or the developing device itself, from the Junko photo itself, and as a result, the developing device, which has not been a problem in the past, has increased. Splashing from the bottom can no longer be ignored as it can cause negative effects such as staining the user's own hands or causing health problems by being scattered into the air.

On the other hand, conventional development methods include a development method using one-component magnetic toner, a development method in which magnetic particles are confined in a developer container and only non-magnetic toner is sent to the development section, and a conventional development method using magnetic particle spikes. A two-component development method is known and has been put into practical use, in which toner is densely packed on a sleeve and development is performed while bringing the toner into contact with the toner.

Each of these development methods has its advantages, but it also has its disadvantages.
There is a need for a developing method that can support colorization and achieve stable image formation.

The present invention is a developing method developed based on such background technology, in which magnetic particles and toner particles are supplied to the developing section like the conventional two-component developing method, but the developing efficiency is higher than that of the conventional two-component developing method. We have developed a new developing method that provides only fewer magnetic particles and fewer toner particles than the component developer to the developing section, thereby freeing the surface of an image carrier such as a sleeve from the magnetic particles.

In this new developing method, since there is no large amount of magnetic particles as in the conventional two-component developing method, toner tends to separate from the sleeve surface, which is recognized as a new problem.

In addition, in this development method, there is almost no loss of magnetic particles during development, but there are cases where they are lost due to not being collected in the developer container or leaking from the developer container, so it is difficult to adjust the development conditions. There are also problems that make it inadequate.

A new problem that did not occur in the two-component development of .k must be solved from the two objectives of improving image quality and preventing stains around the device.

(l) The purpose of the present invention is to solve the new problems that have arisen in such new development. The purpose is to prevent toner scattering.

(Ill Required) The invention achieves this object by releasing the surface of the developer carrier with 3r6 particles standing on the developer carrier and forming a toner particle layer on the released surface. like,
means for regulating the supply amount of magnetic particles and toner particles; a developer container having the regulating means and a developer carrier in an opening and containing magnetic particles and toner particles therein; and an inside of the developer container. , and is located at a position upstream of the regulating means in the developer carrier conveying direction.

means for preventing the magnetic particles from flowing out to the upstream side in the direction of conveyance of the developer carrier; said barrier II: located on the upstream side of the means in the direction of conveyance of the developer carrier; a 11f sheet having an end portion and allowing magnetic particles and toner particles to enter in the conveying direction;
To prevent the toner particles from flowing to the upstream side with respect to the transport direction, it is possible to prevent the toner particles from flowing to the upstream side.
・This is a developing station A which is characterized by containing a sheet member and a sheet member.

(The present invention achieves stabilization of development conditions by preventing the loss of magnetic particles and preventing toner particles from flowing out of the apparatus with this configuration.

(Embodiment) FIG. 1 is a schematic sectional view of a developing device according to an embodiment of the present invention. First, the configuration of the developing device will be explained. l is a latent image carrier having a latent image to be developed, and is an insulating drum for electrostatic recording, or a-3e, CdS, Zn0%,
It is a photosensitive drum or a photosensitive belt having a photoconductive insulating material such as 0PC1α-Si, and is referred to as a drum in the figure, and rotates in the direction of arrow B. The developing sleeve 2 is in contact with or close to the photosensitive drum 1, and rotates in the direction of arrow A in the figure. The developing sleeve 2 is a non-magnetic sleeve made of, for example, an aluminum ram.The developing sleeve 2 is inserted into the container 11 with its right half circumferential surface into a horizontally elongated opening formed in the left side wall of the developing container 4 in the longitudinal direction of the container, and its left substantially half circumferential surface is inserted into the container 11. It is exposed to the outside and mounted horizontally on a bearing for free rotation.

Incidentally, the developing sleeve 2 may be a developer carrying member of an endless belt-h which is rotationally driven.

The sleeve 2 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 2, and the magnetic particles exist here at a volume ratio of -V (1.5 to 30%). This point will be discussed later.

The magnet 3 is statically fixed inside the sleeve 2 and remains stationary even when the sleeve 2 is rotated. Magnet 3 is Brake F, which will be described later.
Collaborate with g to apply developer to sleeve 2-P! St magnetic pole that controls the amount of ti, and Nl that is a magnetic pole that sandwiches the developing section and conveys the developer.

It has an S2 magnetic pole and an N2 magnetic pole that transports the developer from the 52 magnetic pole into the container Aoi 4 after passing through the developing section.

The S and N poles may be reversed. Although this magnet is a permanent magnet in this embodiment, an electromagnet may be used instead.

In this embodiment, the blade 6 has at least its tip made of a non-magnetic material such as aluminum, extends in the longitudinal direction of the sleeve 2 near the top of the opening of the container 4, and has its base fixed to the container 4, The tip side faces the surface of the sleeve 2 with a gap therebetween. The gap between the tip of the blade 6 and the surface of the sleeve 2 is 50 to 500 gm, preferably 10 gm.
It is 0 to 350 μm, and in this example, it is 250 pm. If this gap is smaller than 50 gm, magnetic particles tend to clog the gap, and if it exceeds 500 pm, a large amount of magnetic particles and toner will pass through the gap, making it difficult to form a developer layer of an appropriate thickness on the sleeve 2-t. The thickness of the developer layer that cannot be formed is smaller than the gap between the photosensitive drum 1 and the sleeve 2 in the developing section, which will be described later. In order to create a developer layer with such a thickness, it is preferable that the gap between the blade tip and the sleeve surface be as small as the gap between the sleeve surface and the photosensitive drum surface. The above is also possible.

On the inside side of the container 4 of the blade 6, there is provided a magnetic particle circulation limiting member 5 whose end surface is an undercut surface, which limits the circulation area of the magnetic particles in the container 4, which will be described later.

The power supply 34 applies a voltage between the photosensitive drum 1 and the sleeve 22 to form an alternating electric field in the gap therebetween, thereby transferring the toner from the developer on the sleeve 22 to the photosensitive drum 1. The voltage from the power source 34 may be a symmetrical alternating voltage in which the positive and negative beam 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 W, for example, for an electrostatic latent image with a dark area potential of -600V and a bright area potential of -200V, a DC voltage of -300V is superimposed to increase the peak φ peak voltage by 30V.
A mating voltage of 0 to 20.0 OVPp and a frequency of 200 to 3000 Hz is applied to the sleeve 22 side, and the photosensitive drum 1 is held at the ground potential.

The lower part of the container 21 extends in the direction of the photosensitive tram 1 to form an extension to prevent the developer (particularly toner particles) from leaking to the outside. Further, in order to further ensure such leakage prevention, a lower seal 11 is provided at the end of the passage section. The door seal 11 is located closer to the two wheels than the position of the magnetic pole N1 and the magnetic body 9 that form the magnetic particle restraining magnetic field in the sleeve rotation direction A. The magnetic pole N2 and the magnetic body 9 form a curtain of magnetic particles, which prevents the magnetic particles 7 in the container 4 from flowing out from this member to the extension, and also prevents the toner from flowing out. However, due to the existence of this magnetic material 9, it is observed that toner on the surface of the magnetic particles collected by the curtain and toner not used for developing the sleeve 1- is slightly separated from each other, and for example, after copying about 2,000 sheets. When removed, the amount may amount to about 0.5 to 1 g, and it is quite possible that it will spill outside when replacing the developer or handling the process cartridge.

Therefore, by using the lower seal 11, it is possible to completely collect such scrap toner.

In FIG. 1, the lower seals 11 are film-shaped and are provided evenly in the longitudinal direction so as to close the gap between the sleeve 2 and the developing unit 4.

The sealing member 11 is oriented forward in the direction of rotation of the sleeve 2, that is, the end of the sealing member faces in the direction of rotation of the sleeve 2. The side surface 111 of this seal member 11 is
It is urged to come into contact with the surface of the sleeve 2 (in this example, it is directed by its own adhesive return force). This side surface itt is the part not facing the magnetic pole, the U-shaped magnetic pole S
2. It is located between N2 and slides on the surface of the developer layer where magnetic particles are densely packed. The biasing force of the sealing member is set to such an extent that it allows the collected magnetic particles attached to the sleeve to enter without damaging it, and at the same time allows most of the collected toner to enter. In this embodiment, the member 11 is made of a Mylar sheet having a thickness of 25 pm as a whole, including the end side of the sealing member, and satisfies this condition.

Here, the developing process in the developing device will be described in detail. It adheres over the entire surface of the sleeve 2 and constitutes a layer of magnetic particles. 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 7 initially introduced above originally contain 2 to 70% (by weight) toner based on the magnetic particles.
If the magnetic particles 7, which may be only magnetic particles, are adsorbed and held as a magnetic particle layer on the surface of the -H sleeve 2, no substantial flow or inclination will occur even if the device is vibrated or tilted considerably, and the sleeve 2 The surface remains covered.

Next, when the sleeve 2 is rotated in the direction of the arrow, the magnetic particles rise from the F section of the container 4 in a direction along the surface of the sleeve 2 and reach the vicinity of the blade 6. Therefore, a part of the magnetic particles passes through the gap between the tip of the plate 6 and the surface of the sleeve 22 together with the toner, and the other part bumps against the member 5, then turns around and follows the outside of the L ascending path of the magnetic particles. It descends with the blade to reach the lower part of the container 4, rises again near the sleeve 2, and repeats the above operation.

Note that some of the magnetic particles 7 rising from the lower part of the container 4 against the blade 6 turn around and fall before reaching the vicinity of the blade 6. This is particularly noticeable in magnetic particles far from the surface of the sleeve 22.

In this way, the magnetic particles that turn around and fall near or in front of the blade 6 are transferred from the toner layer 8 at the lower side of the blade 6 to the toner layer 8 that moves in the lateral force direction as the rotating supply member 10 rotates clockwise. It takes in particles.

By circulating the toner four times as the sleeve 2 rotates, the toner is charged by friction between the magnetic particles 7 and the surface of the sleeve 2.

Near the front side of the blade 6, the magnetic particles 7 near the surface of the sleeve 2 are drawn to the surface of the sleeve 22 by the magnetic pole SL, and as the sleeve 2 rotates, they pass through the side of the blade 6 and exit the container 4. At this time, the magnetic particles 7 carry out the toner attached to their surfaces together. Further, some of the toner particles exit the container on the sleeve 2 while remaining attached to the surface of the sleeve 2 due to the reflection force. The blade 6 regulates the developer IIj applied to the sleeve 2-A.

The developer layer (g2 combination of magnetic particles 27 and toner 28) thus formed on the surface of the sleeve 2 reaches a developing section facing the photosensitive drum 1 as the sleeve 2 rotates. Here, toner is transferred from the surface of the sleeve 2 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 2, and the latent image is
develop. The volume ratio of magnetic particles in the developing section is 1.5~
It is 30%. This will be explained in detail.

As the sleeve 22 continues to rotate, the toner particles and magnetic particles that have not been consumed in development are collected in the container 4 through the sealing member 10, and are again coated on the sleeve 2 within the container 4 by the above-mentioned circulation action. Repeat the process. During this recirculation, the magnetic particles take in toner from the toner layer in the container 4-F section, and are supplied with the amount of toner consumed in development.

FIG. 2 is an enlarged sectional view for explaining behavior in the developing section. In this example, the magnetic pole 5123b is arranged in the developing section. The photosensitive drum 1 carries charges constituting a latent image, and in this embodiment, the charges constituting the static image have negative polarity, and the toner is charged to positive polarity. Further, in this embodiment, the photosensitive drum 1 and the sleeve 2 rotate as shown by the arrows so as to move in the same direction. The above-mentioned AC ri 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 2, there is a magnetic pole 23b of the magnet 2 corresponding to the closest portion between the photosensitive drum 1 and the sleeve 2.

In this space, there is a developer, which is a mixture of the magnetic particles 27 and toner 28, which have been conveyed by the rotation of the sleeve 2 as described above. In the case of the development method using the so-called one-component non-magnetic developer thin layer, the magnetic particles 27 are present here.
9-101680). Also, the volume ratio of magnetic particles in this part (described later)
Because of this relationship, the amount of magnetic particles present is much smaller than in the usual so-called magnetic brush development method, and in this respect it is also different from the magnetic brush development method. Due to the action of the magnetic pole 23b, 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 ears 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 on the surface of the magnetic particles is not obstructed by the ears. By forming a uniform open surface on the sleeve surface, the toner adhering to the sleeve surface can be flown from the sleeve surface to the photosensitive drum surface by an alternating electric field.

Here, the behavior of magnetic particles and the flight of toner particles will be explained.

As shown in FIG. 2, in this embodiment, the electrostatic latent image is composed of negative charges (dark portions of the image), so the electric field due to the electrostatic latent image is in the direction indicated by arrow a. The direction of the electric field due to the alternating electric field changes alternately, but in the phase where the positive component is applied to the sleeve 2 side, the direction of the electric field due to this matches the direction of the electric field due to the latent image. At this time, the electric charge 1i1 injected into the ears 51 by the electric field becomes maximum, and therefore the ears 51 are in the maximum standing state as shown in the figure, and the long ears extend to the surface of the photosensitive drum 1.

On the other hand, since the toner 28 on the surface J- of the sleeve 2 and the magnetic particles 27 is positively charged as described above, it 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 the phase shape fπ1, the surface of the sleeve 2 is exposed, and the toner 28 is released from inside the surface of the sleeve 2 and the surface of the ears 51. In addition, since the spike 51 has a charge having the same polarity as the toner 28, the toner 28 on the surface of the spike 51 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 2, the electric field due to the alternating Ichikawa (arrow b) is in the opposite direction to the electric field due to the electrostatic PvI image (arrow a). Therefore, the electric field in this space becomes strong in the opposite direction, the amount of charge injected becomes relatively small, and the ears 51 are brought into a contracted contact state in response to the charge injection.

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 2 or the magnetic particles 27 by the electric field formed in this space. In this way, the toner 28 reciprocates between the photosensitive drum 1 and the surface of the sleeve 2 or the surface of the toner 28, and as the space between them expands due to the rotation of the photosensitive drum 1 and sleeve 2, the electric field becomes weaker. The developing action is complete.

In the spike 51, there are charges injected by frictional charges or mirror charges with the toner 28, static latent image charges on the photosensitive drum 17, and alternating fields between the photosensitive drum 1 and the sleeve 2. The state changes depending on the charging/discharging time constant of the charge determined by the material of the magnetic particles 27 and other factors.

As described above, the spikes 51 of the magnetic particles 27 are brought into a state of slight but intense vibration due to the two alternating electric fields.

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 2 to the photosensitive drum 1. "Volume ratio" is the percentage of the volume occupied by the magnetic particles present in the developing section with respect to the volume of the developing section.As a result of various experiments and considerations, the inventor of the present invention has found that this volume ratio is important in the above-mentioned developing device. to have an effect, and to define this as 1.
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 concentration on the surface of the sleeve 2. 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, which is undesirable because fogging may occur.

Particularly, one aspect of the present invention is that the image quality does not monotonically deteriorate or increase as the volume ratio increases or decreases;
Sufficient image density is obtained in the range of ~30%, image quality deteriorates even if it is less than 1.5% or exceeds 30%, and there is no sleeve ghost or fog within the range of the hill index value where this image quality is sufficient. The name of the invention, which does not occur, is based on the °19 fruit discovered. The deterioration in image quality in +iii is thought to be due to negative characteristics, and the latter name arises from the fact that the amount of magnetic particles present becomes large and it becomes impossible to open the sleeve 2 surface, resulting in a significant decrease in the amount of toner supplied from the sleeve 2 surface. it is conceivable that.

On the other hand, if it is less than 1.5%, the reproducibility of line images is poor and the image quality and density are significantly lowered. On the other hand, if it exceeds 30%, there are problems such as magnetic particles damaging the surface of the photosensitive drum and problems with transfer and fixing caused by the adhesion of the image to the device.

When the presence of magnetic particles is close to 1.5%, when reproducing a large-area uniform high-density image (solid black),
Since there are cases where partial development unevenness called ``developing unevenness'' occurs (under special circumstances, etc.), it is preferable to set the IJ1 ratio so that these are unlikely 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, the presence of magnetic particles is 30
%, there may be a delay in toner replenishment from the sleeve surface around the area where the ears of magnetic particles come into contact (at high development speeds, etc.), which may cause scale-like density unevenness when reproducing solid black. be. 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
On the second surface, the spikes 51 are formed in a preferably sparse state, and the toner on both the sleeve 2 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 of 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, a minute but intense spike signal is generated, thereby loosening the magnetic particles and the toner adhering to the sleeve 2. In any case, it is possible to prevent uneven sweeping and ghost images that occur in the case of magnetic brushes.

Furthermore, due to the vibration of the ears, the magnetic particles 27 and toner 28
Since the frictional contact with the toner 28 becomes active, the frictional electrification of the toner 28 is improved, and fogging can be prevented. Note that high developing efficiency is suitable for downsizing the developing device (d).

The volume ratio of the magnetic particles 27 existing in the developing section is (M/
h) X (1/p) ) Application: 1
r, (g/cm'), h is the height of the developing section space am), ρ is the true electric current of the magnetic particles lWg/cm', C/
("r+c) is the weight ratio of magnetic particles in the developer of sleeve 1-.

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

When the alternating electric field is strong (the rate of change is large or VPP is large) as in the above embodiment, the ears 51 separate from the sleeve 2 or from its base, and the separated magnetic particles 27 are placed between the sleeve 2 and the photosensitive drum 1. make a reciprocating motion in the space of

Since the energy of this reciprocating motion is large, the effect of the vibration described above is further promoted.

The above behavior was observed using a high-speed camera (newly manufactured by Hitachi).
This was confirmed by taking pictures at frames per second.

Even if the gap between the surface of the photosensitive drum 1 and the surface of the sleeve 2 is reduced to increase the contact pressure between the photosensitive drum 1 and the brush 51 and to reduce vibration, the gap is large at the entrance and exit sides of the developing section. Sufficient vibration occurs to produce the above-mentioned effect.

In any case, in this type of development method, in which the number of magnetic particles is smaller than in the conventional two-component development method, the binding force of the magnetic particles on the toner decreases, so when a load occurs, the toner particles are sealed by the magnetic field. Since the toner leaks from the part (magnetic material 9), toner scattering may occur, and it is important to prevent loss of magnetic particles while preventing toner scattering in order to stabilize development conditions.

In this example, the end of the seal member 11 is provided so as to extend in the rotational direction of the sleeve, so that toner and magnetic particles can be collected without being lost outside the apparatus. On the other hand, this configuration is important because if this end is provided in the counter direction, it will instead encourage the separation of toner and cause loss of magnetic particles.

Further, since the side surfaces of the sealing member 11 are provided so as to make surface contact (contact), there is an effect of collecting toner into the toner device, and it is possible to prevent toner from scattering.

Since the present seal system has magnetic particles interposed between the sleeve and the seal member, the load on the toner is small, and it is sufficiently applicable to, for example, toner for pressure fixing.

In this example, the sleeve system is φ20, the N2J4i of the magnet is 800G, the gap between the magnetic seal 9 and the sleeve 2 is 2mm, and the seal 11 is a 25gm mylar sheet between the magnet's 32 and N2 poles. ” It was arranged so that it would add up.

The magnetic particles 7 are uniform particles (60 μm ferrite particles and S
Apply the developer to the developing sleeve 21 using a resin coated with a resistance fIC of lO3Ωam.
, b+, is 2. OXIO-2g/cm'
It was about. Even after running about 2,000 sheets under these conditions, there was almost no toner scattering from the bottom of the developing device, and there were no negative effects on the images! There was no effect. Further, when the developing device was taken out from the main body and shaken or tilted, almost no scattering occurred from the lower part of the developing device.

As for the sealing member 11 of this embodiment, at least the vicinity of the end portion is 25. A thickness of ~50 tiles is preferred. thickness 5
If it exceeds 0 l, the surface contact pressure will increase, which will hinder the collection of magnetic particles and l·ner, so it is preferably 50 or less.

As described above, in this embodiment, Mylar was used as the sealing member 11, but it is also possible to use a durable resin sheet such as nylon, polyimide, polycarbonate, vinylon, polyethylene, FTFT, etc.
1 ability.

In FIG. 1, the position where the seal member 11 contacts the sleeve 2 is between the magnetic poles of the fixed magnet 3. This is because the height of the magnetic brush is low between the magnetic poles, resulting in a more complete seal. However, as in this embodiment, the developer is not applied onto the sleeve! The amount of Ii is 2.
If it is less than the conventional two-component magnetic brush development coating IIfT'J, which is about 0 x 10-2 g/cm', even if the contact part of the seal with the sleeve is at the magnetic pole position, of course good.

The present invention includes everything based on the gist of the claims.

(Effects) The present invention solves the problems that have arisen with the new JJT development method, and is aimed at solving the problem that occurred with the new JJT development method. and has an end portion facing the developer carrier conveyance direction, which allows magnetic particles and toner particles to enter in the conveyance direction, and prevents toner particles from flowing out to the upstream side with respect to the conveyance direction. Since the sheet member is elastically biased toward the developer carrier, it is possible to prevent toner from scattering while preventing loss of magnetic particles that would deteriorate development conditions.

[Brief explanation of drawings]

FIG. 1 is a detailed explanatory diagram of the present invention, and FIG. 2 is an enlarged explanatory diagram of a developing section for explaining the developing method of the present invention. 1 is a photosensitive drum, 2 is a sleeve, 4 is a developer container, and 6 is a blade. 11 is the lower seal.

Claims (3)

[Claims] (1) A developer carrier that transports magnetic particles and toner particles while supporting them in a developing section formed between the developing object, and a magnetic field generator provided on the rotation center side of the developer carrier. and a supply amount of the magnetic particles and toner particles such that the surface of the developer carrier is released with the magnetic particles standing on the developer carrier and a toner particle layer is formed on the released surface. a developer container having the regulating means and a developer carrier in an opening and containing magnetic particles and toner particles therein; means for preventing the magnetic particles from flowing out to the upstream side in the direction of conveyance of the developer carrier, located upstream in the direction of conveyance of the developer carrier; , an end portion facing the developer carrying member in the conveyance direction, which allows magnetic particles and toner particles to enter in the conveyance direction, prevents the toner particles from flowing out to the upstream side with respect to the conveyance direction, and prevents the developer carrier from flowing out to the upstream side with respect to the conveyance direction. A developing device comprising: a sheet member elastically biased toward a carrier; (2) The edge of the sheet member is 25 μm to 50 μm
The developing device according to claim 1, wherein the developing device is a thin film within the range of . (3) The developing device according to claim 1 or 2, wherein the position where the end of the sheet member is close to the developer carrier is opposed between spaced apart magnetic poles of the magnetic field generating means. Device.