JPH08227224A - Developing device - Google Patents

Abstract

PURPOSE: To apply a triboelectric charge while preventing the overcharge of toner and to apply a toner layer having fixed layer thickness by excellently regulating magnetic toner of a one-component developer carried on a developing sleeve with a layer thickness regulating member. CONSTITUTION: As the layer thickness regulating member, a regulating roller 3 is provided which has a magnetic/elastic material 3b dispersed with a magnetic material and set on a core metal 3d and a surface layer 3c formed on the magnetic/elastic material 3b. The regulating roller 3 is brought into elastic press-contact with the surface of the developing sleeve 2 to form a nip and rotated in the same direction as that of the sleeve 2 at a circumferential speed slower than that of the sleeve 2 in a nip part. Then, one magnetic pole N1 of a magnet 7 inside the sleeve 2 is arranged in a position facing the regulating roller 3. Thus, the magnetic toner 4 carried on the sleeve 2 is regulated by the elastic contact of the regulating roller 3 in the nip part and a magnetic field from the magnet 7 to the regulating roller 3.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a developing device used in an electrophotographic device such as a copying machine or an optical printer.

[0002]

2. Description of the Related Art As a developing device used in an electrophotographic apparatus such as a copying machine or an optical printer, one using a magnetic toner as a one-component developer is known, and is carried on a developing sleeve (developer carrying member). A regulating member is provided on the developing sleeve in order to regulate the layer thickness of the magnetic toner. This restricting member is conventionally made of a plate-shaped or roller-shaped elastic material or a plate-shaped or round bar-shaped magnetic material.

The regulating member made of an elastic material is pressed against the surface of a developing sleeve axially supported at a predetermined position of the developing device main body with the magnetic toner carried thereon sandwiched therebetween, and the pressure and the developing sleeve. The layer thickness of the toner on the developing sleeve is regulated according to the nip formed between the two, and a toner layer having a constant layer thickness is applied on the developing sleeve. On the other hand, the regulating member made of a magnetic material is disposed apart from the surface of the developing sleeve, and cooperates with the magnetic force generating means included in the developing sleeve to form a magnetic field in the space between the developing member and the developing member. The layer thickness of the magnetic toner on the sleeve is regulated, and the toner is applied to a constant layer thickness.

[0004]

However, the above-mentioned restriction member has hitherto had the following problems.

Elastic member regulating member: (1) Since the regulating member is fixed to the main body of the developing device and is pressed against the developing sleeve, the developing sleeve and the regulating member are greatly worn, and the abrasion of these members is accompanied. The toner on the developing sleeve cannot be regulated to an appropriate layer thickness, scattering may occur, and the application of triboelectric charge to the toner may become unstable; (2) Pressure of regulating member and setting of nip Is difficult.

Magnetic material regulation member: (1) The ability of the regulation member to impart triboelectric charge to toner may be generally inferior to that of the elastic material regulation member; (2) between the regulation member and the developing sleeve. It is difficult to set the distance.

An object of the present invention is to impart a triboelectric charge with a high imparting ability to a magnetic toner of a one-component developer carried on a developing sleeve while preventing excessive electrification by a layer thickness regulating member, and toner. (EN) Provided is a developing device capable of applying a toner layer having a constant layer thickness on a developing sleeve by satisfactorily regulating the layer thickness thereof and easily obtaining an image with high resolution.

[0008]

The above object can be achieved by the developing device according to the present invention. In summary, the present invention provides:
A developer container containing a magnetic toner of a one-component developer and an opening portion facing the image carrier of the container, which carries the toner and rotates to convey the toner to the developing unit facing the image carrier. And a magnet having a plurality of magnetic poles arranged in a non-rotatable manner inside the developer carrying body, and contacting the surface of the developer carrying body with the toner carried on the developer carrying body. On the other hand, in a developing device having a regulating means for regulating the layer thickness thereof and preventing the layer from flowing out from the opening, the regulating member is a rotatable regulating roller composed of an elastic material and a magnetic material. The regulating roller is pressed against the surface of the developer carrier so as to form a nip for sandwiching the toner, and one of the magnetic poles of the magnet is arranged at a position facing the regulating roller. Is.

According to the present invention, the regulation roller is rotated in the same direction as the developer carrying member in the nip portion and in the direction lower than or opposite to the developer carrying member. Further, the regulation roller may be one in which an elastic material layer is provided on a cored bar made of a magnetic material, and a surface layer may be provided on the elastic material layer. A magnetic material can be dispersed in the elastic material layer. Preferably, the shaft or roller body of the regulation roller is supported by a support member that is freely movable only in the vertical direction. With this configuration, the regulation member can be pressure-contacted to the developer carrying member by a magnetic attraction force between the magnetic material inside the regulation roller and the developer carrying member and gravity applied to the regulation roller. With such a configuration method, stable pressure contact is possible even with respect to abrasion of the regulation roller due to long-term use.

[0010]

【Example】

Embodiment 1 FIG. 1 is a sectional view of an essential part showing an embodiment of the developing device of the present invention. In the figure, reference numeral 1 is a photosensitive drum (image carrier) that rotates in the direction of the arrow, and the main developing device is arranged in the vicinity of the photosensitive drum 1 and is formed on the surface of the photosensitive drum 1 by a latent image forming means (not shown). The developed electrostatic latent image is developed and used as a toner image for visualization.

The developing device is a magnetic toner 4 which is a one-component developer.
And a developing sleeve 2 containing a roller-shaped permanent magnet 7 is rotatably installed in the opening facing the photosensitive drum 1. The developing sleeve 2 is formed of a metal such as stainless steel or aluminum, or a hard synthetic resin, and has a diameter of 32 mm in this embodiment. The surface of the developing sleeve 2 was roughened by sandblasting or sandpaper so that the roughness of the irregularities was 0.2 to 10 μm, preferably 0.5 to 4 μm. The rough surface of the developing sleeve 2 prevents the toner 4 from slipping between the nips, and makes it possible to sufficiently receive the triboelectric charge. The developing sleeve 2 carries the toner 4 in the container 5 and rotates in the direction of the arrow to convey the toner 4 toward the developing portion facing the photosensitive drum 1.

According to the present invention, the regulating roller 3 constituted by using a magnetic material and an elastic material is installed as a toner layer thickness regulating member at a position substantially above the developing sleeve 2 in the opening of the developing container 5. Has been done. In this embodiment, as shown in FIG. 2, the regulation roller 3 has a magnetic elastic material layer (intermediate elastic layer) 3b in which a magnetic material is dispersed on a non-magnetic core metal 3a.
Is provided, and the elastic member layer (surface layer) 3c is provided thereon. Urethane rubber, foam sponge, or the like is used as the elastic material of the magnetic elastic material layer 3b. Ferrite particles or the like are used as the magnetic material.

The regulation roller 3 is moved by being attracted by the magnetic force of the magnet 7 inside the developing sleeve 2, and the developing sleeve 2 is moved.
Is supported by the developing container 5 so as to be freely movable in the vertical direction of the developing sleeve 2 by the supporting member 12 alone attached to the shaft (core metal) 3a thereof. In this embodiment, the regulating roller 3 is supported by the supporting member 12 and elastically abuts on the surface of the developing sleeve 2 so as to form a nip for sandwiching the toner, and is regulated in the same direction as the developing sleeve 2 by a driving source (not shown). It is rotated at a peripheral speed ratio of. The nip width is appropriately set in consideration of the pressure between the regulation roller 3 and the developing sleeve 2, the elastic force of the regulation roller 3, and the peripheral speed difference between these.

A blade 6 fixed to the developing container 5 is brought into contact with the upper portion of the regulation roller 3, and the blade 6 prevents the toner 4 in the container 5 from flowing out through its opening. There is.

In the regulating roller 3 described above, in the nip portion facing the developing sleeve 3, the magnetic elastic material layer 3b in which the magnetic material is dispersed is located at the nip portion of the magnet 7, and the magnetic pole N ₁ is located.
To form a magnetic field toward the magnetic elastic material layer 3b from the above, and magnetically regulates the layer thickness of the magnetic toner 4 carried on the developing sleeve 2. Further, the surface layer 3c of the regulation roller 3 elastically abuts on the surface of the developing sleeve 2 via the toner 4 to regulate the layer thickness thereof, and the toner 4 is frictionally charged.

A material for frictionally charging the toner 4 to a predetermined polarity is selected for the surface of the regulation roller 3. For example, a synthetic resin such as Teflon (trademark) is used when the toner is positively charged, and a synthetic resin such as nylon is used when the toner is negatively charged. However, if a roller having a small frictional resistance such as Teflon is used for the surface of the regulating roller 3 and the surface of the developing sleeve 2 is made smooth, the toner easily passes through the nip portion, and the toner layer thickness regulation and triboelectrification are sufficiently performed. Not always. In such a case, it can be solved by roughening the surface of the developing sleeve 2.

The developing container 5 is formed in a housing containing the toner 4, and in order to prevent the toner 4 from leaking from the container 5, the developing container 5 is provided with a developing portion at a lower portion of the opening in which the developing sleeve 2 is arranged. A film-like seal member (not shown) that closes the gap between the lower portion of the sleeve 2 and the lower portion is installed. As described above, the blade 6 prevents toner from leaking from between the opening of the container 5 and the regulation roller 3.

In the present embodiment, it has already been stated that the regulating roller 3 rotates in the same direction as the developing sleeve 2 at the nip portion, but according to the rotation of the developing sleeve 2 and the regulating roller 3 in the same direction as described above, It is possible to prevent toner or foreign matter that is sandwiched between the nips and agglomerated and discharged to the outside of the nip, thereby forming a streak-like region where no toner exists on the supply roller 2.

The peripheral speed of the regulation roller 3 is preferably lower than the peripheral speed of the developing sleeve 2. Regulation roller 3
If the peripheral speed is equal to that of the developing sleeve 2, the toner on the developing sleeve 3 may pass through the nip portion as it is while being sandwiched between the toner and the regulating roller 3. In that case, not only the toner on the developing sleeve 2 cannot be regulated to a predetermined layer thickness, but also the triboelectric charge amount necessary for the development cannot be given, which results in insufficient development of the latent image or the development sleeve 2 The toner will also be scattered from above. Therefore, the peripheral speed of the regulation roller 3 may be slower than the peripheral speed of the developing sleeve 2.

Further, the rotation of the regulation roller 3 may be continuous rotation or intermittent rotation.

The developing operation of the present developing device will be described. In FIG. 1, the toner carried on the developing sleeve 2 moves to the position of the regulating roller 3 as the developing sleeve 2 rotates, enters the nip where these are in pressure contact with each other, and the triboelectric charge of a predetermined polarity is applied. At the same time, the layer thickness is regulated.

As shown in FIG. 3, in the nip portion, the magnetic field from the magnet 7 in the developing sleeve 2 formed between the magnetic material in the magnetic elastic material layer 3b of the regulation roller 3 (the line of magnetic force is shown in FIG. 3 indicated by reference numeral 10) occurs over a wide range and has a sufficient magnetic regulation force for the toner on the developing sleeve 2. Therefore, the magnetic regulation of the toner layer thickness is stable.

That is, in the area upstream of the nip portion in the rotation direction of the developing sleeve (denoted by reference numeral A in FIGS. 1 and 3), the magnetic force formed by the magnet 7 and the magnetic material of the regulation roller 3 causes the magnetic force on the developing sleeve 2. Toner 4 is loosened,
The toner is lifted along the magnetic lines of force 10 and mixed and stirred with the toner in the developing container 5. Therefore, it is possible to prevent the toner on the developing sleeve 2 from being excessively charged.

At the outlet of the nip portion, the toner attracted by the magnetic lines of force between the magnet 7 and the magnetic material in the regulation roller 3 forms a brush on the surface of the developing sleeve 2. The magnetic brush of this toner is elastically regulated by the regulation roller 3 to form a fine brush, and is formed into a thin toner layer having a uniform layer thickness. As a result, development without scattering is achieved and a high quality image is obtained.

The toner having passed through the nip portion reaches the developing portion facing the photosensitive drum 1 as the developing sleeve 2 rotates. In this developing section, the photosensitive drum 1 and the developing sleeve 2
Are opposed to each other with a gap of 100 to 500 μm, and the toner flies from the developing sleeve 2 to the photosensitive drum 1 by the action of the alternating electric field generated by the AC bias applied between the developing sleeve 2 and the photosensitive drum 1. , Is attached to the latent image on the photosensitive drum 1, and the latent image is developed as a toner image.

In the present invention, as described above, the regulation roller 3 is used.
The nip portion is formed by contact between the developing sleeve 2 and the developing sleeve 2,
Therefore, the toner on the developing sleeve 2 is regulated, but it is necessary to roughen at least one surface of the developing sleeve 2 and the regulating roller 3 or to give elasticity to a proper toner layer by regulation. It is effective in obtaining the thickness and the impartation of sufficient electrostatic charge. Hereinafter, this will be described.

FIG. 4 is an enlarged view of the nip portion of the developing device shown in FIG. 2. In FIG. 4A, when the developing sleeve 2 is rigid and the surface is a mirror surface, in FIG. This is the case when the surface is roughened with a rigid body.

In the present invention, the rotation direction of the regulation roller 3 is set to be the same direction at the nip portion with the developing sleeve 2. However, as described above, the peripheral speed of the regulation roller 3 is higher than that of the developing sleeve 2. I'm late. Therefore, the regulation roller 3 rotates in the opposite direction relative to the developing sleeve 2. At this time, if the surface of the developing sleeve 2 is a mirror surface as shown in FIG. 4A, the toner 4 sandwiched between the nips is rubbed only on the contact surface between the developing sleeve and the regulation roller. . Thus, toner charging is only seen in a limited part of the toner.
Further, since the developing sleeve 2 is a mirror surface, the sandwiched toner moves and passes by sliding between the nips.
For this reason, although the toner is loosened and made uniform to some extent in the nip portion, the toner uniformizing effect has a limit of the layer thickness similarly to the charging effect.

This problem is solved by roughening the surface of the developing sleeve 2. That is, as shown in FIG. 4B, when the surface of the developing sleeve 2 is roughened, not only the regulating roller 3 but also the developing sleeve 2 has toner 4 between the nip.
As a result, a strong frictional force is exerted on the toner, and the toner becomes effective in the direction of the arrow. As a result, the movement of the toner 4 between the nips becomes vigorous, and the toner 4 is sufficiently disentangled and made uniform, and at the same time, the respective surfaces of the toner are rubbed against each other, whereby sufficient triboelectric charges are applied. That is, by roughening the surface of the developing sleeve 2, the toner passing between the nips is sufficiently charged, and the toner is satisfactorily disentangled to form a uniform toner layer. Will be sent to.

The rough surface formed on the surface of the developing sleeve 2 has a surface average roughness of 0.2 to 10 μm, preferably 0.1.
By forming an uneven surface having a particle size of 5 to 4 μm and smaller than the toner particle size to be used, good results were obtained in that a good charge was applied to the toner and a uniform toner layer was formed by loosening.

In this embodiment, in addition to the developing sleeve 2 described above, the regulation roller 3 is provided with a magnetic elastic material layer 3b and an elastic surface layer 3c so as to have sufficient elasticity, so that the toner is charged. Is effective for. The regulation roller 3 can sufficiently rub the toner 4 in the nip. Therefore, simply by passing the toner through the nip portion, the toner can be triboelectrically charged to a potential necessary for the toner, and a large frictional force due to rubbing is applied to the toner to loosen the toner.

As the elastic material, usable materials may be limited in consideration of the fact that the toner can be charged to a predetermined polarity and that the toner does not chemically change. This can be solved by using a plurality of elastic layers as in the regulation roller 3 of this embodiment. The regulation roller 3 has, as an elastic layer, an intermediate elastic layer 3b in which a magnetic material is scattered, and a surface layer 3c thereon.

According to the structure of the regulation roller 3 as described above,
Since the elastic layer b that actually presses the toner 4 against the surface of the regulation roller 3 is separated from the toner 4 and the surface layer 3c,
No chemical adverse effects. Further, since the surface layer 3c can also be formed by a component completely different from the intermediate elastic layer 3b in which the magnetic material is scattered, the selection range of the material is widened, and it is possible to select the material in which the charging characteristics of the toner are sufficiently taken into consideration. Become. Therefore, the performance of the developing device can be further improved.

An experimental example according to this embodiment will be described.

Experiment 1 A stainless steel pipe having a diameter of 32 mm was used as the developing sleeve 2, and the surface thereof was sandblasted to give an average roughness of 2
It was made a rough surface of μm. Magnet 7 contained in the developing sleeve 2
The magnetic flux density of the magnetic pole N ₁ facing the regulating roller 3 is 1000 gauss, and the magnetic pole S ₁ facing the photosensitive drum ₁ is 900 gauss.

The regulating roller 3 was manufactured as follows. A urethane roller in which iron powder is scattered is cast on a stainless steel core having a diameter of 10 mm to obtain a rubber roller having a diameter of 24 mm. The surface of the rubber roller is further covered with a nylon heat-shrinkable tube, and a roller having an outer diameter of 25 mm. Finished. The hardness of the regulation roller 3 thus obtained was 40 ° in Asker C. The regulating roller 3 was pressed against the surface of the developing sleeve 2 with a force of about 1.5 kg, and the nip width was 1.0 mm.

The developing sleeve 2 was rotated at a peripheral speed of 50 mm / sec, and the regulating roller 3 was rotated at 150 mm / sec. The distance between the developing position of the photosensitive drum 1 and the developing sleeve 2 is 250 μm.
Then, an alternating voltage having a frequency of 2.7 kHz and a peak-to-peak voltage of 1.4 kVpp is applied as a developing bias between the developing sleeve 1 and the photosensitive drum 2 to form a negative latent image of -400 V on the photosensitive drum 1. Developed.

By using the developing device having the above-mentioned structure, the density is adjusted within a range in which a proper image is obtained (that is, the copy density is adjusted to 0.4 to 0.5 with respect to the original density of 0.3), and then the development is performed. By providing, image formation was performed.
The original was A4 size with an image ratio of 6%, and the number of copies was 1000.

As a result, a copy density of 1.4 or more was obtained for a document density of 1.2. Also in reproducibility of fine lines,
When a line drawing in which a black character area with a density of 1.1 or more and a white background area with a density of 0.1 are alternately arranged at regular intervals in a width of 1.0 mm and seven lines are copied, the obtained copy image is a thin line. 1
It was possible to confirm each one separately. Further, the copy image has a fog of 0. 0 on the white background (less than 0.1) of the original.
It was suppressed to less than 6%. Further, the toner consumption amount per one A4 copy for the document having the image ratio of 6% is 0.0
25g, toner coat amount on the developing sleeve 2 is 0.8m
g / cm ² , charge amount per unit mass of toner is −18 μ
It was C / g. The average particle size of the toner used is 9 μm.
Is.

Next, the material for the intermediate elastic layer 3b of the regulating roller 3 was changed from urethane rubber in which iron powder was dispersed to only urethane rubber, and the other tests were conducted in the same manner as described above. As a result, the toner coat amount on the developing sleeve 2 was 1.0 mg / cm ² , and the charge amount per unit mass of toner was −14 μC / g, which was A for a document with an image ratio of 6%.
The amount of toner consumed per four copies was 0.035 g. Further, although a copy density of 1.4 or more could be obtained with respect to the document density of 1.2, reproducibility could not be obtained with copying of fine lines, and the fog on the white background portion was 0.8%.

Experiment 2 In Experiment 1, development was performed with the rotation of the regulation roller 3 stopped. Other than that was the same as the experiment 1. As a result, the toner coat amount on the developing sleeve 2 is 0.6 mg /
cm ² , charge amount per unit mass of toner is -18 μC /
Thus, the toner consumption amount per one A4 copy for an original having an image ratio of 6% is 0.020 g. The copy density was less than 1.2 with respect to the original density of 1.2. It was possible to obtain reproducibility by copying fine lines, and the fog on the white background was less than 0.6%.

Experiment 3 The regulating roller 3 was used for development under the conditions of rotating at the same peripheral speed as in Experiment 1 and the condition of stopping the rotation, and 20,000 sheets of image were formed.

When the regulating roller 3 was rotated, the developing device was not hindered and no white streak pattern was observed in the obtained image.

However, when the rotation of the regulation roller 3 is stopped, the width of the image is about 0.5 m when the development is performed for 2000 sheets.
Many white streak patterns of m were generated. As a result of examination of the cause, it is recognized that individualized toner and foreign matter are nipped in the nip between the developing sleeve 2 and the regulation roller 3 and these remove the toner on the developing sleeve 2. It was

Next, when the regulating roller 3 was rotated in the same direction and at the same peripheral speed in the nip portion as the developing sleeve 2, not only a sufficient image density was not obtained for the image,
Toner fogging occurred on the white background. This confirms that the toner was not sufficiently charged by the regulation roller 3 and that the toner on the developing sleeve 2 was applied excessively thickly.

As described above, by rotating the regulating roller 3 in the nip portion in the same direction as the developing sleeve 2 and at a low peripheral speed, the toner and foreign matter that are sandwiched between the nips and discharged are discharged to the outside of the nip to develop. It can be seen that the area where the stripe-shaped toner does not exist is prevented from being formed on the sleeve 2.

As described above, when the peripheral speed of the regulation roller 3 is set to be the same as that of the developing sleeve 2, as described above, the toner on the developing sleeve 2 is sandwiched between the regulation roller 3 and the toner. Since the toner may pass through the nip portion as it is, not only the toner on the developing sleeve 2 cannot be regulated to a predetermined layer thickness, but also the triboelectric charge amount necessary for development cannot be imparted, resulting in insufficient development of the latent image. It may also cause the toner to scatter from the developing sleeve 2. Therefore, it is preferable to set the peripheral speed of the regulation roller 3 to be lower than the peripheral speed of the developing sleeve 2.
0% or less.

As described above, in the present invention, the toner layer thickness regulating member is formed of a material containing an elastic material and a magnetic material, or a material containing an elastic material which is also a magnetic material, like the regulating roller 3. By using a regulation roller, the magnetic toner carried on the developing sleeve is provided with a high triboelectric charge while preventing excessive charging, and the toner layer thickness is well regulated, and the developing sleeve is well regulated. A toner layer having a constant layer thickness can be applied on the upper surface, and an image with high resolution can be easily obtained.

Embodiment 2 FIG. 5 is a diagram showing another embodiment of the present invention. Example 1
Then, in the nip portion of the regulation roller 3, the developing sleeve 2
However, in this embodiment, the regulation roller 3 is rotated in the opposite direction by a drive source (not shown).

In this case, at the nip portion, the developing sleeve 2
And the opposing surface of the regulation roller 3 are positively moved in the opposite directions, so that even if foreign matter or the like enters the nip, the effect of removing it from the nip is improved, and toner is replaced near the nip. Ability increases.

Further, in this embodiment, with respect to the regulation roller 3,
A scraper 7 was installed instead of the blade 6 as in the first embodiment. Therefore, the scraper 7 can prevent not only the outflow of the toner from the container 5 but also the adhesion of the toner to the regulation roller 3.

Embodiment 3 FIG. 6 is a diagram showing still another embodiment of the present invention. In the first and second embodiments up to now, the core metal (shaft) 3a, which is the rotation center of the regulation roller 3, is made of a rigid body having no magnetism, but in the regulation roller 8 of this embodiment, it is made of a rigid magnetic material. The regulating roller 8 is provided with a magnetic material layer 8b around the magnetic core metal 8a, and a surface elastic layer 8c on the magnetic material layer 8b. The magnetic material layer 8b can also be made of a rigid magnetic material.

According to this, the magnet 7 in the developing sleeve 2 is
Due to the action of the magnetic field with the rigid core 8a of the regulation roller 3 from above, a stronger magnetic restraining force can be obtained with respect to the toner 4 on the developing sleeve 2, and even application of toner in the nip portion and proper charging are further achieved. You can be sure.

[0054]

As described above, in the developing device of the present invention, the layer thickness regulating member is a rotatable regulating roller using an elastic material and a magnetic material, and the regulating roller of the developing sleeve is used. The surface is pressed so as to form a nip for sandwiching the magnetic toner of the one-component developer, and one of the magnetic poles of the magnet is
One is placed at the position opposite to the regulation roller, and the magnetic toner carried on the developing sleeve is regulated by the elastic contact of the regulation roller and the magnetic field from the magnet to the regulation roller. It is possible to impart an electrostatic charge and to apply a toner layer having a constant layer thickness on the developing sleeve.
Therefore, good development can be easily performed to easily obtain an image with high resolution.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of essential parts showing an embodiment of a developing device of the present invention.

FIG. 2 is an enlarged cross-sectional view showing a nip portion where a regulating roller and a developing sleeve installed in the developing device of FIG. 1 are in contact with each other.

FIG. 3 is an explanatory diagram showing a magnetic field in a nip portion of FIG.

FIG. 4 is an explanatory diagram showing the movement of toner in the nip portion when the surface of the developing sleeve in FIG. 2 is a mirror surface and a rough surface.

FIG. 5 is a cross-sectional view of essential parts showing another embodiment of the present invention.

FIG. 6 is a cross-sectional view of an essential part showing still another embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Photosensitive drum 2 Development sleeve 3 Regulation roller 3a Core metal 3b Magnetic elastic material layer 3c Surface layer 4 Magnetic toner 6 Blade 7 Scraper 8 Regulation roller 8a Magnetic core metal 8b Magnetic material layer 8c Surface elastic layer 12 Support member

Claims (7)

[Claims] 1. A developing container containing a magnetic toner of a one-component developer, and a toner container, which is disposed in an opening portion of the container facing the image carrier, carries the toner and rotates to face the image carrier. And a magnet having a plurality of magnetic poles arranged in a non-rotating manner inside the developer carrying member, abutting on the surface of the developer carrying member, In a developing device having a regulating means for regulating the layer thickness of the carried toner and preventing the toner from flowing out from the opening, the regulating member is a rotation member composed of an elastic material and a magnetic material. A restriction roller which is capable of being pressed against the surface of the developer carrying member so as to form a nip for sandwiching the toner, and one of the magnetic poles of the magnet is disposed at a position facing the restriction roller. Characteristic developing equipment Place. 2. The developing device according to claim 1, wherein the regulation roller is rotated in the same direction as the developer carrying member in the nip portion, and the peripheral speed thereof is lower than the peripheral speed of the developer carrying member. 3. The developing device according to claim 1, wherein the regulating roller is rotated in a direction opposite to that of the developer carrier at the nip portion. 4. The developing device according to claim 1, 2 or 3, wherein the regulation roller comprises an elastic material layer provided on a cored bar made of a magnetic material. 5. The developing device according to claim 4, wherein a surface layer is further provided on the elastic material layer. 6. The developing device according to claim 1, wherein a magnetic material is dispersed in the elastic material layer. 7. The shaft of the regulation roller or the roller body is
7. The developing device according to claim 1, wherein the developing device is supported by a supporting member that is freely movable only in the vertical direction.