JPH1173022A - Developing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the occurrence of deterioration in image quality, in the case where the latent image formed on an image carrier is visualized by the adhesion of a toner, by controlling the toner density and toner electric charge in the two-component developer with a simple constitution. SOLUTION: A developing roll 2 equipped with a turnable hollow cylindrical sleeve 2a and a magnetic field generating member 2b positioned in the inside thereof is arranged in the position opposed to a photoreceptor 1. In the position where the developing roll 2 is brought into contact with the developer being carried on the roll 2, a damming up member 3 for collapsing and stagnating a part of the developer is arranged, so that a fresh toner can be supplied to the stagnated developer from a toner housing part 6. In the toner supply region A where the toner is supplied, a variable magnetic field from the magnetic field generating member 2b is acted, and the toner is stirred up with the developer by the magnetic field thereof. To produce a strong magnetic field in the toner supply region A, the damming up member 3 may be made of a magnetic material, or another stirring member may be provided.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a developing device which is used in an electrophotographic recording device or an electrostatic recording device or the like, and selectively transfers toner to a latent image due to a difference in electrostatic potential to visualize the developing device. The present invention relates to a developing device using a two-component developer in which a carrier and a toner are mixed.

[0002]

2. Description of the Related Art In an electrophotographic method, a developing method using a two-component developer containing a toner and a magnetic carrier has advantages in that toner is easily charged and toner particles are hardly aggregated. For this reason, although it is necessary to control the amount of toner contained in the two-component developer, that is, the toner concentration, it has been widely used conventionally.

FIG. 17 is a schematic configuration diagram showing an example of a conventionally known developing device using a two-component developer. The developing device is disposed so as to be close to and opposed to the image carrier 201, and controls a developing roll 202 that magnetically attracts and transports the developer, and regulates an amount of the developer that is attracted onto the developing roll. A developer regulating member 203 that is a substantially uniform magnetic brush; a paddle 204 that supplies the developer to the developing roll 202; and two augers 205 and 206 that transport and agitate the developer in the housing 210.
And

The developing roll 202 includes a fixedly supported magnet roll 211 and a cylindrical sleeve 212 that is driven to rotate around the magnet roll 211. The magnet roll 211 adsorbs the developer onto the sleeve, and the sleeve 212 The developer is conveyed to the portion facing the image carrier 201 by the rotation of.

[0005] The two augers 205 and 206 are provided with two stirring chambers 20 provided behind the developing roll 202.
At 7 and 208, the developer is rotated so as to convey the developer in opposite directions, and the developer is circulated in two stirring chambers communicating at both ends.

In such a developing device, the stirring chamber 207,
In 208, the carrier and the toner are sufficiently stirred, and a part of the developer is supplied to the developing roll 202 by the paddle 204. The developer is attracted onto the sleeve 212 by the pickup magnetic pole 213 of the magnet roll 211, and after the layer thickness is regulated by the developer regulating member 203, the developer is conveyed to the development area and subjected to development.

The developer that has passed through the developing area is released from above the sleeve 212 by the pick-off magnetic pole 214 and returned to the stirring chamber by the paddle 204. Here, it is mixed with the other developer and the newly supplied toner, and is sufficiently stirred.

[0008] The charge amount of the toner of the developer used in such a developing device fluctuates depending on the environmental conditions and also largely fluctuates depending on the toner concentration in the developer. FIG.
Shows the relationship between the toner density and the toner charge amount in the two-component developing device as described above under environmental conditions of high temperature and high humidity, medium temperature and medium humidity, and low temperature and low humidity. In general, the charge amount of the toner fluctuates with the characteristics as shown in FIG. 18, but in order to obtain constant development characteristics under each environmental condition, the charge amount of the toner must be kept constant. For this purpose, it is necessary to perform the following control.

That is, the operating environment is high temperature and high humidity (see FIG. 1).
8, the toner is replenished when the temperature changes from medium temperature / humidity (state indicated by reference numeral b 'in FIG. 18) to the toner density, the toner density is increased from A to B, and the charge amount of the toner is set to a predetermined value. (The state indicated by the symbol “b” in FIG. 18). The environmental conditions are low temperature and low humidity (Fig. 1
8 when the toner density changes from medium temperature / humidity (state indicated by reference sign d in FIG. 18) to medium temperature / humidity (state indicated by reference sign d in FIG. 18).
From B to B, so that the charge amount of the toner becomes a predetermined value (the state shown by the symbol b in FIG. 18). However, in the conventional two-component developing device, there is no means for lowering the toner density except for consuming the toner, and there is a problem that the charge amount of the toner is reduced and the background portion is fogged.

In order to control the toner density, control is performed to actually develop the reference image, detect the density, and replenish the toner. Is needed. Under these circumstances,
A developing device for controlling the toner density with a simple mechanism to obtain an image with a stable density is disclosed in
No. 11664, JP-A-63-287874,
It is described in Japanese Patent Publication No. Hei 5-59427 and Japanese Patent Laid-Open No. Hei 7-84456.

The technique described in Japanese Patent Application Laid-Open No. Sho 59-111664 discloses a magnetic transfer means comprising a magnet roller and a non-magnetic sleeve provided separately on the outer peripheral surface thereof, and a magnetic transfer means formed on the non-magnetic sleeve. And a rotatable toner supply roller so as to be in contact with the rising edge of the developer to be supplied. A toner layer thickness regulating member (blade) is brought into contact with the toner supply roller to charge the toner supply roller surface. Form a thin layer of toner. When replenishing toner from the toner supply roller to the developer on the non-magnetic sleeve, a predetermined level of potential difference is applied between the non-magnetic sleeve and the toner supply roller, and the non-magnetic sleeve is supplied from the surface of the toner supply roller. By controlling the amount of toner transfer to the toner, the toner density is kept substantially constant.

The technique described in Japanese Patent Application Laid-Open No. 63-287874 discloses a technique in which a developer conveyed by a developing roll is regulated to a desired thickness by a regulating plate, and the developer separated from the developing roll is gravity moved in a container. The developer is dropped, and the dropped developer is transported again by the developing roll. In this manner, the rotation of the developer is formed, and the toner is kept in a constant state by intermittently contacting the toner with the rotating developer.

The technique described in Japanese Patent Publication No. 5-59427 discloses a technique in which the magnetic brush on a sleeve is rubbed against a mesh screen arranged in an opening of a toner hopper to thereby remove toner in the toner hopper. By moving the magnetic brush to the magnetic brush, the self-adjustment of the toner density is performed.

The technology described in Japanese Patent Application Laid-Open No. H7-84456 discloses a technology in which the periphery of a developing roller is made a narrow space, and the amount of a carrier in the space is made substantially constant so that the magnetic toner accommodated in the remaining space can be removed. The amount is adjusted so that the toner density is controlled to be substantially constant.

[0015]

However, the above-mentioned developing device has the following problems. In the developing device described in JP-A-59-111664,
By pressing the toner layer regulating member against the toner supply roller, a thin layer of charged toner is formed on the toner supply roller. Therefore, a strong frictional force acts between the toner layer regulating member and the toner, so that the toner is filmed on the toner supply roller, and the toner is not smoothly supplied from the toner supply roller to the developing roller. Or poor charging of the toner.

In the developing device described in Japanese Patent Application Laid-Open No. 63-287874, in order to cause the developer to rotate, the developer is completely separated from the developing roll and dropped by gravity, and the developing roll is again rotated. Therefore, there is a problem that the developer on the developing roll cannot be rapidly stirred because the developer is pulled upward, and a relatively large space is required for the rotation of the developer.

Further, in order to sufficiently agitate the rotating developer, it is necessary to set the magnetic force of the developing roll to be strong. Therefore, there is a problem that the developer is deteriorated in a portion where the magnetic brush is shaped. is there. In addition, there is a large difference in the amount of toner to be replenished between a case where a solid image having a gradation such as a photograph, a picture, and a map is mainly printed and a case where a line image is mainly printed. In the method of rotating the developer, since a constant amount of toner is always taken in by the mechanical rotation of the developer, the supply amount of toner cannot be changed according to the image to be printed.
There is a problem that it is difficult to keep the toner density constant.

The developing device described in Japanese Patent Publication No. 5-59427 has a problem that the developer is rubbed against the mesh screen, so that stress is applied to the developer and the life of the developer is greatly reduced. . In addition, since the fluidity of the toner and the chargeability of the toner, that is, the adhesive force between the toner and the carrier, greatly contribute to the control of the toner density, when the fluidity and the chargeability of the toner change with the environment or with time, the toner density is changed There is a problem that the control range deviates from the initially set range and the print quality differs from the initial one.

Further, there is a large difference in the amount of toner to be replenished between a case where a solid image having a gradation such as a photograph, a picture and a map is mainly printed and a case where a line image is mainly printed. In the mesh screen method, since the contact area between the carrier and the toner is limited, it is difficult to keep the toner concentration constant when the amount of the supplied toner fluctuates greatly.

Further, toner is replenished to the developer while the magnetic brush is formed on the magnet roll. However, since the developer is usually in an agglomerated state, the effective contact area of the carrier is reduced, and poor charging toner is generated. It will be easier.

In the developing device described in JP-A-7-84456, a magnetic toner is used, and it is necessary to include a magnetic powder in the toner. There is a problem that mixing cannot be performed and color toner cannot be used. Also, when a non-magnetic toner is used in the present developing device with emphasis on coloring properties,
The magnetic force does not act to attract the toner to the developing roller, and the nonmagnetic toner and magnetic carrier are stirred in a narrow space around the developing roller because the specific gravity difference between the nonmagnetic toner and the magnetic carrier is large. Will not be performed sufficiently. As a result, toner charging becomes insufficient,
There is a problem that toner cannot be sufficiently supplied to the developer supplied to the developing area.

The invention according to the present application has been made in view of the above-mentioned problems, and its object is to
It is possible to control the toner concentration and toner charge amount in the two-component developer with a simple configuration, and stable and good image quality even when environmental conditions fluctuate and toner usage fluctuates due to differences in originals Is provided.

[0023]

In order to solve the above-mentioned problems, the invention according to claim 1 uses a two-component developer containing a magnetic carrier and a toner that is electrically attracted to the magnetic carrier. A developing device for selectively transferring the toner to an electrostatic latent image formed on an image carrier and visualizing the toner, wherein the peripheral portion is circulated independently or integrally with an endless peripheral surface; A plurality of magnetic poles are magnetized along the surface,
These magnetic poles adsorb the two-component developer on the peripheral surface, form a developer layer in which the magnetic carrier has a spike shape, and move the plurality of magnetic poles around or around the peripheral surface. A developer transport member for transporting the component developer, damping at least a part of a chain of the two-component developer layer carried on the developer transport member, and a magnetic attraction force of the developer transport member. In the region where the acts, a developer stirring section for stirring the two-component developer,
It is assumed that a toner supply unit that supplies a substantially limit amount of toner that can electrically adsorb the magnetic carrier to the two-component developer in the developer stirring unit is provided.

In such a developing device, a two-component developer layer in which magnetic carriers are spike-shaped is formed on the surface of the developer conveying member, and the two-component developer is moved by the circumferential movement of the plurality of magnetic poles or the circumferential surface. The carrier is conveyed, but the developer agitating section dams part of the chain of the two-component developer layer carried on the developer carrying member, whereby the individual particles of the carrier are relatively dispersed, and the toner and Many contactable carrier surfaces can be formed. At the same time, in the region where the developer has collapsed, the magnetic field acting on the collapsed developer constantly changes due to the rotation of the developer transport member, and the developer is in a state of being agitated.

By supplying the toner to the area where the developer has collapsed, the toner in contact with the carrier is charged and adsorbed, and at the same time, the toner having a small adhesive force with the carrier is separated from the carrier by the stirring action of the developer. You. In other words, when the toner comes into contact with the portion where the surface of the carrier is exposed, the toner adheres to the carrier by frictional charging. Even when the toner comes into contact with the portion where the toner has already adhered to the carrier surface, the toner contacts the carrier. It cannot be triboelectrically charged and does not adhere to carriers. Further, when the toner on the surface of the carrier is consumed in the development and the surface of the carrier is exposed, when newly supplied toner comes into contact with this portion, the toner is triboelectrically charged and electrostatically adheres to the carrier. When the toner and the developer are agitated in this manner, the toner is carried on the surface of the carrier in a substantially limit amount of toner that can be carried by the carrier.

At this time, the charge amount of the carrier is substantially constant irrespective of environmental conditions, and the average charge amount and the toner amount of the toner particles adhering thereto are also substantially constant. That is, the toner concentration of the developer and the charge amount of the toner after the adsorption of the toner and the separation of the toner having a small adhesive force with the carrier are substantially constant due to the agitating action of the developer, and this is transferred to the developer conveying member. , And subjected to development, an image having a stable density can be formed even when environmental conditions fluctuate.

The cause of the environmental resistance as described above is presumed as follows. That is, when attention is paid to the chargeability of the carrier and the chargeability of the toner, it is considered that the chargeability of the toner is more environmentally dependent. This is because the polymer has a high probability of having a fragmented chain of the polymer on the surface of the toner due to its manufacturing method, and furthermore, since the fragmented chain is active, it easily reacts with water and is susceptible to environmental fluctuations. . On the other hand, since the carrier is usually coated with a coating material, there is no such thing as toner, and the carrier is less susceptible to environmental fluctuations. Therefore, in the conventional method, the amount of toner in the developer is small, and the charge amount of the developer is unsaturated with respect to the chargeability of the carrier. Therefore, the chargeability of the toner becomes dominant, indicating environmental dependency. Would.

However, in the method of the present invention, the developer is agitated in a state in which the individual particles of the carrier are relatively dispersed, so that a sufficient amount of toner can be adsorbed on the carrier and, at the same time, the toner having a small adhesive force can be removed. Since the developer is separated, the charge amount of the developer becomes saturated with respect to the chargeability of the carrier, and the chargeability of the carrier becomes dominant and does not exhibit environmental dependency.

According to a second aspect of the present invention, in the developing device according to the first aspect, the developer transport member is configured such that an S pole and an N pole are alternately attached over the entire periphery of the endless peripheral surface. An internal member that is magnetized and the peripheral surface of which is supported rotatably;
An endless outer peripheral member supported outside the outer peripheral surface of the inner member, wherein the inner member is magnetically adsorbed on an outer peripheral surface of the outer peripheral member which is stationary or driven to rotate. The developer is conveyed on the outer peripheral member, and is driven to rotate so that the spike-shaped two-component developer layer rolls and agitates.

In such a developing device, on the peripheral surface of the outer peripheral member, the leading end of the chain of the two-component developer is attracted to the outer peripheral member surface, and the carrier at the base is attached to the leading end of the ear. By repeatedly causing rolling of the moving developer, the developer after supplying the toner can be sufficiently stirred. For this reason, uniform dispersion of the toner and uniform charging of the toner are appropriately performed.

According to a third aspect of the present invention, in the developing device according to the second aspect, the magnetic poles of the internal member are magnetized such that a magnetic pole interval P is 0.12 mm ≦ P ≦ 6 mm, The strength of the magnetic pole or the amount of the total developer and the amount of the developer in the developer stirring section are such that the layer thickness D of the two-component developer adsorbed on the outer peripheral member by these magnetic poles is D ≦ P / 3. It is assumed that the damming amount is set. The layer thickness D of the developer is set so as to be within the above range on the peripheral surface other than the developer stirring section of the outer peripheral member. Is also good.

By setting the strength of the magnetic pole, or the amount of the entire developer and the amount of damming of the developer in the developer stirring section as described above, the developer on the developer conveying member other than the developer stirring section is set. The layer thickness is made appropriate, and the developer is appropriately rolled and agitated on the peripheral surface of the developer conveying member. The magnetic pole interval P and the layer thickness D of the developer are based on the following experimental results.

The present inventors have proposed a non-magnetic toner having an average particle diameter of 7 μm and an average particle diameter of 50 μm and 10 ⁶ / (4π) A.
/ M in a magnetic field of 25 kA / m to 450 kA
/ M range of the ferrite carrier and the magnetically stirred developer, the spike-shaped developer rolls,
The behavior of the developer in the developer stirring section was investigated in detail.

First, N-poles and S-poles are alternately arranged at equal pitches of 1 to 11 mm inside an endless outer peripheral member having an outer diameter of 36 mm so that the magnetic flux density of each magnetic pole is 10 mT to 80 m.
Each magnet set in the range of T was inserted, and the layer thickness of the developer was changed by changing the magnetic flux density of the magnet and the amount of the developer attached to the outer peripheral member. In this case, since the layer regulating member is not used, the maximum layer thickness is the layer thickness on the magnetic pole.

Then, while the outer peripheral member was fixed, the magnet was rotated at a speed of 500 rpm, and the rolling of the developer generated on the outer peripheral member surface was observed. FIG. 19 shows the result of observing the maximum layer thickness (upper magnetic layer thickness) at each magnetic pole pitch and the rolling by the magnetic force of the developer at that time. from this result,
In the region where the magnetic pole pitch was 6 mm or less, rolling from the root of the developer chain was observed when the thickness of the developer layer on the magnetic pole was 1/3 or less of the magnetic pole pitch. If the thickness of the developer layer on the magnetic pole exceeds one-third of the magnetic pole pitch, the developer near the root of the developer chain cannot roll, and only the tip of the developer chain moves to form an upper layer. It was observed that only parts were stirred.

On the other hand, even in a region where the magnetic pole pitch exceeds 6 mm, the developer near the root of the developer layer becomes difficult to move, and rolling is unlikely to occur. Further, when the layer thickness was small, a portion where the developer had not adhered occurred between the magnetic poles on the surface of the outer peripheral member, and a uniform magnetic brush could not be formed.

From the above results, in order to form a chain in which the developer is spike-shaped uniformly on the outer peripheral member and to cause rolling from the root, the developer having a magnetic pole pitch of 6 mm or less and a developer on the magnetic pole is required. It is understood that the condition where the layer thickness is 1/3 or less of the magnetic pole pitch is optimal. In addition, the rolling of the developer from the root of the chain referred to here is such that the lower layer and the upper layer of the developer on the developer conveying member are switched by the rolling, so that the toner-supplied developer can be efficiently stirred. This means that the toner concentration is made more uniform and the toner charge is promoted.

That is, in the developing device as described above, the inner member in which the S pole and the N pole are alternately magnetized over the entire periphery of the endless peripheral surface of the developer conveying member; An endless outer peripheral member supported outside the surface, and the interval P between the magnetic poles of the internal member is set to 0.12 mm ≦ P
By setting the magnetic pole strength or the amount of the developer such that the layer thickness D of the developer absorbed by these magnetic poles satisfies D ≦ P / 3, Rolling and stirring of the developer are appropriately performed on the developer transport member. As a result, the supplied toner can be more appropriately charged and uniformly dispersed by the effects of both the stirring of the developer in the developer stirring section and the stirring on the developer conveying member.

According to a fourth aspect of the present invention, in the developing device according to the second or third aspect, the magnetic flux density B of each magnetic pole of the internal member satisfies 10 mT ≦ B ≦ 100 mT.

The magnetic flux density B of each magnetic pole is based on the following experiment. The present inventors have developed a non-magnetic toner having an average particle diameter of 7 μm and a non-magnetic toner having an average particle diameter of 5 μm to 100 μm,
The magnetization in a magnetic field of 0 ⁶ / (4π) A / m is 25 kA.
The developer comprising a ferrite carrier in the range of / m to 450 kA / m was stirred by magnetic force, and the appearance of the spike-shaped developer rolling and the behavior of the developer in the developer stirring section were investigated in detail.

First, N-poles and S-poles are alternately arranged at 1 mm, 3 mm, and 6 m inside an endless outer peripheral member having an outer diameter of 36 mm.
The magnetic flux density of each magnetic pole is 5 m
Insert a magnet in the range of T to 120 mT, and fix the magnet at 500 rpm with the outer peripheral member fixed.
The developer was rotated at a speed of m, and the state of rolling of the developer and transport of the developer generated on the surface of the outer peripheral member was observed. As a result, in a region where the magnetic flux density was lower than 10 mT, a phenomenon was observed in which the developer was not transported and scattered from the outer peripheral member. This is because the magnetic binding force on the outer peripheral member is too weak,
This is because the developer cannot be sufficiently held against centrifugal force or the like, so that the developer cannot be sufficiently rolled.

In the region where the magnetic flux density exceeds 100 mT, the scattering of the developer does not occur because the magnetic binding force is strengthened. However, since the developer is densely packed, the magnetic brush becomes hard and the developer is dispersed. Becomes insufficient. From the above,
It is understood that the magnetic flux density of each magnetic pole is preferably in the range of 10 mT or more and 100 mT or less.

According to a fifth aspect of the present invention, in the developing device according to the second, third or fourth aspect, the carrier in the two-component developer has a particle diameter R of 10 μm ≦ R ≦ 80 μm. And the magnetization J in a magnetic field of 10 ⁶ / (4π) A / m is 45 kA / m ≦ J ≦ 360 kA / m.

The range of the particle size and the magnetization of the carrier in the two-component developer is based on the following grounds. The present inventors observed the state of transport and rolling of the developer by using a magnet having a magnetic flux density of each magnetic pole within the above range, changing the particle diameter of the carrier and the value of the saturation magnetization. At that time, in order to dam the developer, a blade was arranged below the center of the outer peripheral member so that the tip was at a distance of 200 μm from the surface of the outer peripheral member. When the behavior of the developer was confirmed in this manner, the particle size of the carrier was 10 μm.
If the ratio is less than the above, although the adhesion of the developer on the outer peripheral member is substantially uniform, the aggregation of the developer occurs, and the transportability is reduced. Therefore, the developer is partially densely formed on the outer peripheral member, and a uniform magnetic brush is not formed. Therefore, sufficient rolling is hindered. Further, a phenomenon is also observed in a region where the developer has been dammed up and subdivided, and a state in which the developer is not densely dispersed and continues to accumulate on the outer peripheral member is observed. On the other hand, when the particle size of the carrier exceeds 100 μm, the amount of the developer that can be held against the magnetic binding force on the outer peripheral member is reduced, so that the developer is easily scattered and good Movement cannot be performed.

Also, 10 ⁶ / (4π) A / m of the carrier
Is less than 45 kA / m in a magnetic field of
The magnetic binding force on the outer peripheral member with respect to the carrier is weakened, so that the developer layer is likely to come off, and a uniform magnetic brush is not formed. Further, since the magnetic binding force is weakened even by the centrifugal force, the developer is scattered. Conversely, the magnetization is 360
If it exceeds kA / m, the developer is more strongly attracted along the magnetic pole because the magnetic binding force is strengthened, and the developer layer becomes partially dense, so that the developer is easily aggregated. Therefore, even in the region where the developer is blocked, uniform dispersion is not performed, and the developer does not have sufficient stirring power.

As described above, if the magnetization in a magnetic field of 10 ⁶ / (4π) A / m is 45 kA / m to 360 kA / m, the formation and development of a uniform magnetic brush are possible. Good results are obtained with respect to the rolling from the root of the developer chain or the dispersibility of the developer in the developer stirring section.

According to a sixth aspect of the present invention, in the developing device according to the first aspect, the second aspect, the third aspect, the fourth aspect, or the fifth aspect, the developing device faces the developer conveying member with a gap. And a damming member that breaks and blocks a part of the chain of the developer formed on the developer conveying member, and the upstream side of the damming member is the developer stirring section. Shall be.

In the developing device as described above, a carrier having a simple structure is provided by providing a damming member for breaking at least a part of the ears of the two-component developer carried on the peripheral surface of the developer conveying member and damming it. In a state where individual particles are relatively dispersed, that is, the developer can be subdivided, and the subdivided developer can be stirred. That is, by damping at least a part of the ears of the two-component developer carried on the peripheral surface of the developer conveying member, a magnetic field constantly fluctuating due to the rotation of the developer conveying member acts on the blocked developer. Then, the developer can be rolled and agitated by the action of the magnetic field.

According to a seventh aspect of the present invention, in the developing device according to the sixth aspect, at least a part of the dam member is formed of a magnetic material. In the invention described in claim 8, the dam member has a magnet. By forming the damming member from a magnetic material or adding a magnet, the strength of the magnetic field acting on the damped developer can be increased, and the stirring action of the developer can be promoted.

According to a ninth aspect of the present invention, in the developing device according to the sixth aspect, a vibrating means for vibrating the dam member is provided.

According to a tenth aspect of the present invention, in the developing device according to the ninth aspect, the vibrating means is provided so as to be in contact with the dam member, and mechanically vibrates the dam member. There is.

According to an eleventh aspect of the present invention, in the developing device according to the ninth aspect, the vibrating means is provided to face the dam member, and an alternating voltage is applied between the dam member and the dam member. Electrode member.

According to a twelfth aspect of the present invention, in the developing device according to the sixth aspect, a vibrating member vibrates in contact with the developer blocked by the damming member.

By vibrating the damming member mechanically or electrically, or by vibrating the developer on the damming member, the stirring of the damped developer is promoted, and the developer having a constant toner concentration can be more reliably produced. Can be obtained.

According to a thirteenth aspect of the present invention, in the developing device according to the sixth aspect, the developer conveying member is disposed on the developer conveying member at a downstream side of the dam member in the developer conveying direction. And a stirring means for stirring the two-component developer carried on the developer conveying member.

In such a developing device, the two-component developer replenished with the toner carried on the developer carrying member by the stirring means is sufficiently stirred and downstream of the dam member.
By mixing, the toner concentration in the developer can be more uniformly dispersed, and the toner charge amount can be kept constant.

According to a fourteenth aspect of the present invention,
Wherein the stirring means is a magnetic member disposed so as to face the peripheral surface of the developer conveying member with a gap therebetween.

In the developing device as described above, the stirring means is
By using a magnetic member that is opposed to the peripheral surface of the developer conveying member with a gap therebetween, a magnetic field can also be applied to the developer after passing through the developer agitating section, and the replenished toner is further reduced. Stir so as to be uniformly dispersed in the developer.
As a result, the toner can be more uniformly dispersed and the toner can be more favorably charged.

According to a fifteenth aspect, a thirteenth aspect is provided.
In the developing device described in the above, the agitating means, an S-pole and an N-pole are alternately magnetized over the entire periphery of the endless peripheral surface, and an internal member whose peripheral surface is rotatably supported, An endless outer peripheral member supported outside the outer peripheral surface of the inner member, wherein the two-component developer magnetically adsorbed on the outer peripheral surface of the outer peripheral member that is stationary or driven to rotate is provided. The internal member is driven to rotate so that the two-component developer layer formed in a spike shape is rolled and agitated while being conveyed on the outer peripheral member.

In such a developing device, on the peripheral surface of the outer peripheral member supported outside the inner member as the magnetic field generating means,
The leading end of the chain of the two-component developer is attracted to the surface of the sleeve, and the rolling of the developer that moves the carrier at the base of the chain to the leading end of the chain repeatedly occurs. For this reason, the developer after supplying the toner can be sufficiently stirred, and the toner can be uniformly dispersed and the toner can be further charged.

The invention according to claim 16 is the invention according to claim 15
In the developing device described in the above, each magnetic pole of the internal member,
Magnetization is performed so that the magnetic pole interval P is 0.12 mm ≦ P ≦ 6 mm, and the layer thickness D of the two-component developer adsorbed on the outer peripheral member by these magnetic poles is D ≦ P / 3. It is assumed that the strength of the magnetic pole or the amount of developer and the amount of developer damping in the developer agitating section are set.

By setting the strength of the magnetic pole or the amount of the developer and the amount of the damping of the developer in the developer stirring section as described above, the toner was replenished as described in the above experimental results. The developer can be appropriately rolled. For this reason, the developer to which the toner has been replenished can be efficiently stirred, and the toner can be more uniformly dispersed and the toner can be further charged.

According to the seventeenth aspect of the present invention,
Alternatively, in the developing device according to claim 16, the magnetic flux density B of each of the magnetic poles of the internal member satisfies 10 mT ≦ B ≦ 100 mT.

The invention according to claim 18 is the first invention.
5. The developing device according to claim 16, wherein the carrier in the two-component developer has a particle diameter R of 10 μm ≦ R ≦ 80 μm and 10 ⁶ / (4π) A / m. It is assumed that the magnetization J in the magnetic field is 45 kA / m ≦ J ≦ 360 kA / m.

As described above, by setting the magnetic flux density of each magnetic pole of the internal member, or the particle size of the carrier and the range of magnetization in the two-component developer, the developer can be used as described in the above-described experimental results. The phenomenon of scattering from the outer peripheral member or agglomeration of the developer is prevented. For this reason, the developer to which the toner has been replenished can be efficiently stirred, and the toner can be more uniformly dispersed and the toner can be further charged.

[0066] The invention described in claim 19 is:
Claim 2, Claim 3, Claim 4, Claim 5, or Claim 6
In the developing device described in (1), the developer stirring section is provided at a position where the developer on the developer transport member is transported in the direction of action of gravity.

In such a developing device, the developer stirring section is provided at a position where the developer on the developer conveying member is conveyed in the direction of action of gravity, so that the magnetic field of the developer conveying member and the gravity are reduced. The developer can be used for rolling and stirring. Therefore, the supplied toner can be efficiently taken into the developer.

The twentieth aspect of the present invention provides the first aspect,
Claim 2, Claim 3, Claim 4, Claim 5, or Claim 6
In the developing device, the developer transport member is disposed so as to be closely opposed to the image carrier, and transfers toner in a two-component developer to an electrostatic latent image on the image carrier. There is.

In such a developing device, the developer which is supplied with the toner on the developer conveying member and is sufficiently stirred has a uniform distribution of the toner and sufficiently charges the toner. Then, the toner in the developer is selectively transferred to an electrostatic latent image on the image carrier. As a result, it is possible to realize a small-sized developing device that has a high developing efficiency and can stably obtain a high-quality image without fog or density unevenness.

The invention described in claim 21 is based on claim 1,
Claim 2, Claim 3, Claim 4, Claim 5, or Claim 6
The developing device according to any one of the preceding claims, wherein the S pole and the N pole are alternately arranged on the peripheral surface that is arranged so as to be closely opposed to the image carrier and that is driven to rotate, at an interval at which almost one carrier layer is attracted. The developer conveying member is disposed so as to be closely opposed to the developing member.

In such a developing device, a developing member whose peripheral surface is supported so as to move around is arranged to face the image carrier, and the developer conveying member is arranged to face this developing member. . Then, the toner is supplied to the developer adsorbed on the developer conveying member, and the developer, which is agitated to make the toner distribution uniform and the toner charged sufficiently, is transferred to the peripheral surface of the developing member. . At this time, since the S pole and the N pole are appropriately magnetized on the peripheral surface of the developing member, a developer layer in which almost one layer of carriers is arranged substantially uniformly is formed. The sheet is transported to a developing area facing the image carrier. In this development area, the toner in the developer is selectively transferred to the image carrier, and the electrostatic latent image is developed.

In such a developing device, the developer can be sufficiently stirred, and a thin and uniform developer layer can be formed without exerting a large addition on the developer. It can be obtained stably over a long period of time. In addition, the magnetization interval of the peripheral surface of the developing member is
When a magnetic carrier having an average particle size of about 25 μm to about 100 μm is used, it is preferable that the average particle diameter be about 25 μm or more and 250 μm or less.

According to a twenty-second aspect of the present invention, an electrostatic latent image formed on an image carrier is formed by using a two-component developer containing a magnetic carrier and a toner that is electrically attracted to the magnetic carrier. In the developing device for selectively transferring and visualizing the toner, the two-component developer is magnetically adsorbed on an endless peripheral surface to form a developer layer in which the magnetic carrier has a spike shape. A developer agitating unit that has a developer transporting member that transports the developer along the surface, at least a part of a chain of the two-component developer held on the developer transporting member in a spike shape is blocked and stays; A toner supply unit that supplies a substantially limit amount of toner that can electrically adsorb the magnetic carrier to the two-component developer in the developer stirring unit; and a toner supply unit disposed behind a wall surface of the housing surrounding the developer stirring unit. Is a rotating drive Is, it is assumed that a magnet to form a variable magnetic field to the developer agitating portion is provided.

In such a developing device, since a rotatable magnet is disposed behind the wall surface of the housing surrounding the developer agitating section, a fluctuating magnetic field is formed in the developer agitating section. The agent is well stirred. For this reason, the toner can be more uniformly dispersed, and a developer in which the toner is sufficiently charged can be obtained.

The developing device according to the twenty-third aspect uses a two-component developer containing a magnetic carrier and a toner that is electrically attracted to the magnetic carrier to form an electrostatic latent image formed on an image carrier. A developing device for selectively transferring and visualizing the toner, having an endless peripheral surface on which the two-component developer is magnetically adsorbed and transported in a peripheral direction; An endless peripheral surface which is close to and opposes the first developer transport member, and magnetically adsorbs the two-component developer on the peripheral surface, and the first developing agent A second developer conveying member that conveys the two-component developer in the same direction as the first developer conveying member at a position facing the developer conveying member; and the first developer conveying member and the second developer conveying member. On the upstream side of the position facing the second developer transport member, the developer is transported on the peripheral surfaces of both developer transport members. A part of the two-component developer is dammed, and a developer agitating section that stays there is formed.
At least one of the developer transport member and the second developer transport member has a plurality of magnetic poles magnetized along a peripheral surface thereof orbitally moving, and the attraction force of a fluctuating magnetic field generated by the magnetic pole is reduced by the developing force. It is assumed that the setting is made so as to cover the two-component developer in the developer stirring section.

In such a developing device, a developer agitating section is provided upstream of the position where the first developer transport member and the second developer transport member oppose each other, in which a part of the two-component developer is dammed. Since the fluctuating magnetic field acts on the developer in this portion, the developer supplied with the toner can be sufficiently stirred. Therefore, the toner can be uniformly dispersed and the toner can be appropriately charged.

The invention according to claim 24 is the invention according to claim 23
In the developing device according to any one of the first developer transport member and the second developer transport member, one of the first developer transport member and the second developer transport member is disposed in close proximity to the image carrier, the toner in the two-component developer It is to be transferred to the image carrier.

In such a developing device, the developer agitated sufficiently by receiving the supply of the toner in the developer agitating section has a uniform toner distribution and sufficiently charges the toner. The toner in the developer is selectively transferred to the image carrier. As a result, it is possible to realize a small-sized developing device that has a high developing efficiency and can stably obtain a high-quality image without fog or density unevenness.

The invention according to claim 25 is the invention according to claim 23
In the developing device according to any one of (1), either one of the first developer transport member and the second developer transport member has an S pole and an N pole alternately formed on a peripheral surface that is driven to rotate. It is magnetized at an interval to attract the carrier layer, and is arranged so that the peripheral surface is also in close proximity to the image carrier, and transfers the toner in the two-component developer to the image carrier. .

In such a developing device, the S-pole and the N-pole are alternately magnetized at an appropriate interval on the peripheral surface of one of the developer conveying members, so that almost one layer of the carrier is substantially formed. A uniformly arranged developer layer is formed, and this developer layer is transported to a development area facing the image carrier. Then, the toner in the developer is selectively transferred to the image carrier, and the electrostatic latent image is developed. In such a developing device, the developer can be sufficiently agitated, and a thin and uniform developer layer can be formed without exerting a large addition on the developer. It can be obtained.

According to a twenty-sixth aspect of the present invention,
In the developing device described in (1), at least one of the first developer transport member and the second developer transport member has S poles and N poles alternated over the entire circumference of the endless peripheral surface. And an endless outer peripheral member supported outside the peripheral surface of the inner member, the outer periphery of the outer peripheral member being stationary or orbitally driven. The two-component developer magnetically adsorbed on the surface is conveyed on the outer peripheral member, and the inner member is driven to rotate so that the two-component developer layer formed into a spike shape rolls and agitates. Shall be used.

In such a developing device, the developer supplied with the toner in the developer stirring section is further stirred on the developer conveying member, so that the toner can be uniformly dispersed and the toner charged more properly. Things.

According to the twenty-seventh aspect of the present invention,
2. The developing device according to claim 1, wherein the magnetic poles of the internal member are magnetized such that a magnetic pole interval P is 0.12 mm ≦ P ≦ 6 mm, and the magnetic poles are attracted onto the outer peripheral member by these magnetic poles. It is assumed that the strength of the magnetic pole, or the amount of the developer and the amount of the damping of the developer in the developer stirring section are set so that the layer thickness D of the developer satisfies D ≦ P / 3.

By setting the strength of the magnetic pole, or the amount of the developer and the amount of damming of the developer in the developer stirring section as described above, the toner was replenished as described in the above experimental results. The developer can be appropriately rolled. For this reason, the developer to which the toner has been replenished can be efficiently stirred, and the toner can be more uniformly dispersed and the toner can be further charged.

According to the twenty-eighth aspect of the present invention,
28. The developing device according to claim 27, wherein a magnetic flux density B of each magnetic pole of the internal member satisfies 10 mT ≦ B ≦ 100 mT.

The invention described in claim 29 is the second invention.
6. The developing device according to claim 27, wherein the carrier in the two-component developer has a particle diameter R of 10 μm ≦ R ≦ 80 μm and 10 ⁶ / (4π) A / m. It is assumed that the magnetization J in the magnetic field is 45 kA / m ≦ J ≦ 360 kA / m.

As described above, by setting the magnetic flux density of each magnetic pole of the internal member, or the range of the particle size and magnetization of the carrier in the two-component developer, the developer can be used as described in the above experimental results. The phenomenon of scattering from the outer peripheral member or agglomeration of the developer is prevented. Therefore, the developer can be efficiently stirred, and the toner can be uniformly dispersed and the charge of the toner can be further improved.

The configuration of the invention according to the present invention is not limited to an apparatus for performing two-component magnetic brush development, but is applied to an apparatus for performing so-called hybrid development in which only a development region functions as one-component development using a two-component developer. be able to.

[0089]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a schematic diagram showing a developing device according to an embodiment of the invention described in claim 1, claim 2, claim 3, claim 4, claim 5, claim 6, claim 19, or claim 20. It is a block diagram. The developing device includes a developing roll 2 that carries a two-component developer on a peripheral surface thereof and conveys the two-component developer to a region facing the photosensitive drum 1 in a housing 7 that stores the two-component developer, and a developing roller 2 that passes through the developing region. A blade (a damping member) 3 for breaking and damping a part of the developer ears on the developing roll 2 and a blade 3 for guiding the replenishment toner to contact the developer whose ears have been broken by the blades 3.
3a, a toner container 6 disposed on the back side of the guide member 3a, and the toner 4 while loosening the toner stored in the toner container 6.
And a toner transport member 5 for transporting the toner. Although not shown, a toner box for replenishing the toner 4 is connected to an end of the toner container 6 in the axial direction.

The developing roll 2 is composed of a hollow cylindrical nonmagnetic conductive sleeve 2a rotatably supported and a magnetic field generating member 2b located inside the sleeve. The magnetic field generating member 2b is provided such that magnetic poles of different polarities are alternately magnetized over the entire circumference and can rotate independently of the outer sleeve 2a.

The sleeve 2a has an outer diameter of 18 mm.
Made of stainless steel. On the peripheral surface of the magnetic field generating member 2b, 18 magnetic poles are alternately magnetized with N poles and S poles at an interval of about 3 mm, and the maximum magnetic flux density (polar magnetic force) of each magnetic pole is reduced. 30 mT. The developer adsorbed on the sleeve by such a magnetic pole has a thickness of 650 μm on the magnetic pole and 350 μm between the magnetic poles.

The chain of the developer formed into a spike on the developing roller 2 having the above-described structure is rotated by the rotation of the magnetic field generating member 2b and the sleeve 2a in the opposite directions. , And is conveyed to the developing area facing the photosensitive drum 1 while being agitated.

The blade 3 has a tip that is a sleeve 2
The toner 4 on the guide member 3a and the developer which is subdivided by the sleeve 2a to break at least a part of the ears is disposed above the blade 3 with the toner 4 on the guide member 3a. Form a toner supply area A that comes into contact. In the present embodiment, the blade 3 and the guide member 3a are integrated, and the distance between the blade 3 and the sleeve 2a is set to 0.1 to 0.5 mm.

The toner conveying member 5 is disposed in the toner container 6 in the housing 7 and sufficiently agitates the toner by rotating in the direction of the arrow shown in FIG. The toner is conveyed. Then, the toner carried near the guide member 3a is guided along the guide member 3a to the toner supply area A which comes into contact with the developer on the sleeve 2a.

The two-component developer used in the above embodiment is a mixture of a non-magnetic polyester toner and a ferrite magnetic carrier. The carrier in the two-component developer has an average particle size of 30 to 60 μm.
And the magnetization in the magnetic field of 10 ⁶ / (4π) A / m is 1
A material having a value of 20 kA / m to 320 kA / m is used. Note that the two-component developer is not limited to the above example, and a toner or a carrier made of another material can be used. A carrier in which magnetic powder is dispersed in a polymer resin has a lower specific gravity than a ferrite carrier, and reduces stress during stirring, which is preferable for the developer life. The toner can be used for both polymerization and mixed grinding.
A spherical shape having high fluidity is preferred.

In such a developing device, the developer carried on the developing roll 2 is transported in the direction of the arrow shown in FIG. A predetermined developing bias voltage is applied between the photosensitive drum 1 and the developing roll 2, and an electric field is formed in a developing area where these are opposed to each other. Is transferred to the toner image, and a toner image corresponding to the latent image is formed. The developer that has passed through the development area is guided to the toner supply area A, and the blade 3
A part of the ear standing is destroyed by.

In the toner supply region A, the magnetic field acting on the developer whose ears have been broken is constantly fluctuated by the rotation of the magnetic field generating member 2b disposed inside the developing roll 2.
Therefore, the developer in which the ears are broken vibrates in a state where the individual particles of the carrier are finely divided and relatively dispersed. When the toner 4 carried along the guide member 3a is supplied to the developer in this state, the toner 4 mixes with the vibrating developer, and when the toner 4 comes into contact with the exposed portion of the carrier surface, The toner 4 is frictionally charged and electrostatically adheres to the carrier surface. The toner 4 that has already contacted the portion of the carrier surface where the toner 4 has adhered cannot be frictionally charged, and does not adhere to the carrier. Further, the toner 4 adhered to the carrier surface or the toner surface by the non-electrostatic adhesion without being frictionally charged with the carrier is shaken off by the vibration of the developer by the magnetic field of the magnetic field generating member 2b. Since the individual particles of the carrier are relatively dispersed by the blade 3, almost all of the carrier surface is covered with the toner 4 by passing through the toner supply area A once.

The developer replenished with the toner 4 is transported again by the developing roll 2 to the developing area facing the photosensitive drum 1. At this time, the sleeve 2a and the magnetic field generating member 2b
Are rotated in the direction of the arrow, so that the developer is conveyed while rotating in the rotation direction of the sleeve 2a, and the toner is uniformly dispersed by rolling and stirring of the developer.

FIG. 2 is a diagram showing changes in toner density and toner charge amount through the above-described steps. According to this figure, immediately after the development, that is, before the toner is supplied, regardless of the charge amount and the toner concentration of the toner regardless of the developing unit and the non-developing unit, the above-described process is performed in the toner supply area A. It can be seen that the charge amount and the toner concentration become substantially constant after passing through. this is,
This is presumed to be because the carrier is able to hold the toner without difficulty, that is, the toner density is in proportion to the chargeability of the carrier due to contact charging with the toner. That is, at least a portion of the developer spike is broken by the blade 3, and the broken developer is stirred by the magnetic force of the magnetic field generating member 2b disposed in the developing roll 2, so that the developer is in the spike state. The surface area of the carrier increases and the number of times of contact with the toner increases. Then, the toner in contact with the carrier is held on the surface of the carrier by frictional charging, and the toner having a weak adhesive force is sieved off by stirring the developer,
It is possible to create a state where the carrier can easily hold the toner.

Next, using the magnetic field generating member 2b in which the maximum magnetic flux density of each magnetic pole was set to 30 mT as described above, changing the carrier particle diameter and the value of the saturation magnetization, and observing the state of transport and rolling. did. At this time, the blade 3 was disposed below the center of the sleeve 2a and such that the tip was at a distance of 200 μm from the sleeve surface. Table 1 shows the results of this experiment. Here, the observation items include the scattering of the developer, the uniformity of the developer layer on the sleeve, the presence or absence of rolling from the root of the developer chain, and the dispersibility of the developer in a region where the developer is subdivided. And As the overall evaluation, all items were evaluated as ○, and other items were evaluated as ×. The value of magnetization in the table is 10 ⁶ / (4π)
The value in the magnetic field of A / m is shown. (Below)

[0101]

[Table 1]

As shown in Table 1, the particle size of the carrier was 10
When it is less than μm, although the uniformity of the adhesion on the sleeve is excellent, the aggregation of the developer occurs and the transportability is reduced. As a result, the developer is partially dense on the sleeve, and a uniform magnetic brush is not formed, so that the rolling of the developer is hindered. Furthermore, a phenomenon was observed in which the developer was similarly dense in the subdivided region, and the developer was not uniformly dispersed, but remained on the blade. On the other hand, when the thickness exceeds 100 μm, the amount of the developer that can be held against the magnetic restraining force on the sleeve decreases, so that the developer is easily scattered and good rolling cannot be performed. I understand.

Also, 10 ⁶ / (4π) A / m of the carrier
Is less than 45 kA / m in a magnetic field of
The magnetic binding force on the sleeve with respect to the carrier is weakened, the developer layer is apt to come off, and a uniform magnetic brush is not formed. Further, since the magnetic binding force is weakened even by the centrifugal force, the developer is scattered. Conversely, the magnetization is 36
If it exceeds 0 kA / m, the magnetic binding force becomes stronger, so that the developer is attracted more along the magnetic poles, and the developer layer becomes partially overcrowded, so that the developer tends to aggregate.
Therefore, even in the subdivided region, uniform dispersion was not performed, and it was found that the region did not have sufficient stirring power.

As described above, if the magnetization in the magnetic field of 10 ⁶ / (4π) A / m is 45 kA / m to 360 kA / m, the uniform magnetic brush formation and development It can be seen that good results are obtained for the rolling from the root of the developer chain or the dispersibility of the developer in the region where the developer is subdivided.
Here, the rolling of the developer from the root of the chain means that the lower layer and the upper layer of the developer on the sleeve are replaced by the rolling, and the toner is agitated so that the supplied toner is uniformly dispersed. .

In the above-described developing device, the rotation directions of the sleeve 2a and the magnetic field generating member 2b are opposite to each other as shown in the figure. Anything can be used. Also, the sleeve 2a
Although both the magnetic field generating member 2b and the magnetic field generating member 2b are rotatable, for example, either the sleeve 2a or the magnetic field generating member 2b may be fixed.

In the developing device having the above structure, the distance between the magnetic poles of the magnetic field generating member 2b located inside the developing roll 2 and the strength thereof and the amount of the developer carried on the developing roll 2 allow the developer on the sleeve 2a to be charged. Although the thickness is adjusted, a layer thickness regulating member may be added to regulate the layer thickness of the developer. This layer thickness regulating member is a magnetic field generating member 2b.
In the case where the thickness of the developer layer varies only by adjusting the magnetic pole interval and the magnetic pole strength, for example, a developer having a substantially desired layer thickness or slightly thicker depending on the magnetic pole interval and its strength is used. To obtain the desired layer thickness,
It is desirable not to apply a large pressure to the developer. This makes it possible to more reliably cause the rolling of the entire developer layer and the accompanying agitation, thereby forming a more uniform developer layer in the development region.

Further, at least a part of the magnetic field generating member 2b used in the developing device may be formed of a magnetic material. Further, as in the sixth aspect of the present invention, the apparatus may have a magnet.
Thereby, the intensity of the magnetic field acting on the toner supply area A can be increased, and the stirring action of the developer can be promoted. In the above-described developing device, the blade 3 and the guide member 3a are attached. However, the developing device may be constituted by a member integrated with the housing 7.

FIG. 3 is a schematic structural view showing a developing device according to one embodiment of the present invention. This developing device includes a developing roll 12 formed by laminating a conductive layer on a magnetic recording layer, instead of the developing roll 2 of the developing device shown in FIG. The developing bias voltage is applied to the conductive layer of the developing roll 12 by a developing bias power supply (not shown). The magnetic recording layer of the developing roll 12 has magnetic poles of different polarities alternately magnetized over the entire circumference.

In this embodiment, the developing roll 12 has an outer diameter of 1
8 mm, and 18 magnetic poles on its peripheral surface are about 3 mm
N poles and S poles were alternately magnetized at pitch intervals, the maximum magnetic flux density (polar magnetic force) of each magnetic pole was 35 mT, and the magnetic pole was rotated at 600 rpm in the direction shown. Blade 13 and toner transport member 15 of this developing device
And the like are the same as those used in the developing device shown in FIG. The carrier of the two-component developer used in this developing device is the same as the carrier used in the developing device shown in FIG.

In such a developing device, the developing roll 12
After passing through the development area, the developer is transported in the direction of the arrow and guided to the toner supply area A. In the toner supply area A, a part of the ears is broken by the blade 13. At this time, the magnetic field acting on the developer whose ears are broken is
Since the developer is constantly fluctuated by the rotation of the developing roll 12, the developer in which the ears are broken vibrates in a state where the individual particles of the carrier are relatively dispersed. When the toner 14 carried along the guide member 13a is supplied to the developer in this state, the toner 14
And the toner 14 is frictionally charged and electrostatically adheres to the carrier surface. The toner 14 that has already contacted the portion where the toner 14 has adhered to the carrier surface cannot be triboelectrically charged and does not adhere to the carrier. In addition, the toner 14 attached to the carrier surface or the toner surface by non-electrostatic adhesion without being frictionally charged with the carrier is shaken off by the vibration of the developer due to the magnetic field of the developing roll 12. Since the individual particles of the carrier are relatively dispersed by the blade 13, most of the surface of the carrier is covered with the toner 14 by passing through the toner supply area A only once. The developer replenished with the toner 14 is transported again to the developing area facing the photosensitive drum 1.

Even in such a developing device, the developer after passing through the developing area is conveyed to the toner supply area A and new toner is replenished, so that the charge amount and the toner density of the toner are made substantially uniform. Can be.

FIG. 4 is a schematic diagram showing the structure of the first, second, third, and fourth embodiments.
Claim 4, Claim 5, Claim 6, Claim 9, Claim 1
FIG. 21 is a schematic configuration diagram showing a developing device according to an embodiment of the present invention described in Item 0, Item 19 or Item 20. This developing device includes a blade 23 in addition to the developing device shown in FIG.
The vibrating member 28 is supported so as to be in contact with the vibrating member. The vibrating member 28 is driven by a motor to
The blade 23 can be vibrated in small increments by applying mechanical vibration to the blade. The configuration of the developing roll 22 and other members of this developing device is the same as that of the developing device shown in FIG. The carrier of the two-component developer used in this developing device is the same as the carrier used in the developing device shown in FIG.

In such a developing device, by vibrating the blade 23, the developer with broken ears can be efficiently stirred, and the toner having a small adhesive force with the carrier can be smoothly shaken from the developer. The effect of dropping and uniformly dispersing the toner can be improved.

FIG. 5 is a schematic diagram showing the constructions of the first, second, third and fourth embodiments.
Claim 4, Claim 5, Claim 6, Claim 9, Claim 1
FIG. 1 is a schematic configuration diagram showing a developing device according to an embodiment of the present invention. This developing device includes a blade 33 in addition to the developing device shown in FIG.
A plate-shaped electrode member 38 is provided in an upper portion thereof opposite to the above. The blade 33 is formed of a conductive material,
9 and the electrode member 38 is electrically grounded. The other structure of the developing device is the same as that of the developing device shown in FIG. The carrier of the two-component developer used in this developing device is the same as the carrier used in the developing device shown in FIG.

In such a developing device, an electric field is formed between the electrode member 38 and the blade 33 by the AC voltage applied from the AC power supply 39, and the blade 33 vibrates according to the change of the electric field. As a result, the developer having broken ears can be efficiently stirred, the toner having a small adhesive force with the carrier can be smoothly shaken off from the developer, and the effect of uniformly dispersing the toner can be improved.

FIG. 6 is a block diagram showing the configuration of the first, second, third, and fourth embodiments.
Claim 4, Claim 5, Claim 6, Claim 12, Claim 1
FIG. 19 is a schematic configuration diagram illustrating a developing device according to an embodiment of the present invention. In this developing device, a frame 48 is provided above and opposite to the blade 43, and a vibration member 49 is attached so as to be in contact with the frame 48. The other structure of the developing device is the same as that of the developing device shown in FIG. The carrier of the two-component developer used in this developing device is the same as the carrier used in the developing device shown in FIG.

In such a developing device, the frame 48 is mechanically vibrated by the vibrating member 49, and vibration is applied to the developer above the blade 43. As a result, the developer having broken ears can be efficiently stirred, the toner having a small adhesive force with the carrier can be smoothly shaken off from the developer, and the effect of uniformly dispersing the toner can be improved.

FIG. 7 shows claims 1, 2, 3,
Claim 4, Claim 5, Claim 6, Claim 13, Claim 1
FIG. 4 is a schematic configuration diagram illustrating a developing device according to an embodiment of the invention described in claim 19 or 20. In this developing device, a magnetic member 58 is disposed downstream of the toner supply area A in the developer transport direction on the developing roll 52 so as to face the developing roll 52. The developer damping member located below the developer stirring area A is formed integrally with the housing 57. The other structure of the developing device is the same as that of the developing device shown in FIG. The carrier of the two-component developer used in this developing device is the same as the carrier used in the developing device shown in FIG.

In such a developing device, the developing roller 5 is located downstream of the toner supply area A in the developer conveying direction.
Since the magnetic member 58 is disposed so as to be opposed to 2,
The magnetic force acting on the developer after passing through the toner supply area A increases, and the rolling and stirring of the developer can be performed more effectively. As a result, further uniform dispersion of the toner is achieved, and charging of the insufficiently charged toner is promoted.

FIG. 8 is a circuit diagram of the first, second, third and fourth embodiments.
Claim 4, Claim 5, Claim 6, Claim 13, Claim 1
5, claim 16, claim 17, claim 18, and claim 19
21 is a schematic configuration diagram illustrating a developing device according to an embodiment of the present invention. This developing device mixes and stirs the developer with a developing roll 62 that carries the two-component developer on its peripheral surface and conveys the developer to a region facing the photosensitive drum 1 in a housing 68 that contains the two-component developer. And a stirring roll 63 as developer stirring means for transporting the developer to a position facing the developing roll 62. A blade 64 for breaking and damaging at least a portion of the ears of the two-component developer carried on the developing roll 62, and a blade for guiding the replenishment toner to contact the developer whose ears have been broken by the blade 64 A guide member 64a integrated with the guide member 64, and a toner conveying member 66 for conveying the toner 65 to the guide member 64a while loosening the stored toner.

The developing roll 62 is rotatably supported and is formed by laminating a magnetic recording layer on a conductive layer.
The developing bias voltage is applied to the conductive layer by a developing bias power supply (not shown). This magnetic recording layer has magnetic poles of different polarities alternately magnetized over the entire circumference.

The developing roller 62 has an outer diameter of 18 mm.
On its peripheral surface, 18 magnetic poles are alternately magnetized with N poles and S poles at intervals of about 3 mm, and the maximum magnetic flux density (polar magnetic force) of each magnetic pole is 35 mT.

The stirring roll 63 is composed of a rotatably supported hollow cylindrical non-magnetic conductive sleeve 63a and a magnetic field generating member 63b located inside the sleeve. The magnetic field generating member 63b is provided such that magnetic poles of different polarities are alternately magnetized over the entire circumference and can rotate independently of the outer sleeve 63a.

The sleeve 63a has an outer diameter of 24 mm.
And is formed of stainless steel. Further, on the peripheral surface of the magnetic field generating member 63b, 15 magnetic poles are alternately magnetized with N poles and S poles at intervals of about 5 mm,
The maximum magnetic flux density (polar magnetic force) of each magnetic pole is 50 mT.

In the present embodiment, the developing roll 62
rpm, the sleeve 63a is 10 rpm, the magnetic field generating member 6
3b is rotated at 600 rpm in the direction shown. The other components of the developing device, such as the blade 64 and the toner conveying member 66, are the same as those used in the developing device shown in FIG. The carrier of the two-component developer used in this developing device is the same as the carrier used in the developing device shown in FIG.

In such a developing device, the developing roll 62
After passing through the developing area, the developer is conveyed in the direction of the arrow shown in FIG.
In the toner supply area A, a part of the ears of the developer is broken by the blade 64. At this time, the magnetic field acting on the developer whose ears have been broken is constantly changing due to the rotation of the developing roll 62. For this reason, the developer in which the ears are broken vibrates in a state where the individual particles of the carrier are relatively dispersed.

When the toner 65 carried along the guide member 64a is replenished to the developer in this state, the toner 65 comes into contact with the exposed portion of the carrier due to agitation, and the toner 65 is triboelectrically charged and electrostatically charged. Adheres to the carrier surface. The toner 65 that has already contacted the portion where the toner 65 has adhered to the carrier surface cannot be frictionally charged and does not adhere to the carrier. Further, the toner 65 adhered to the carrier surface or the toner surface by non-electrostatic adhesion without being frictionally charged with the carrier is shaken off by the vibration of the developer due to the magnetic field of the developing roll 62. Since the individual particles of the carrier are relatively dispersed by the blade 64, most of the surface of the carrier is covered with the toner 65 by passing the toner supply region A only once.

The developer supplied with the toner 65 is carried to a position facing the stirring roll 63. Stirring roll 63
The developer sent from the developing roll 62 is once scraped off by the magnetic brush which is moved by the rotation of the sleeve 63a and the magnetic field generating member 63b in a region opposed to the developing roll 62, and the new developer conveyed from the stirring roll 63 is replaced with the developing roll. 62 and is conveyed to the development area. Developing roll 6
The developer that has been scraped off from the sleeve 2 and becomes spike-shaped on the sleeve 63a rolls with the fluctuation of the magnetic field due to the rotation of both the sleeve 63a and the magnetic field generating member 63b, and is agitated to make the toner concentration uniform. In addition, the insufficiently charged toner is charged. Thereafter, the developer conveyed on the sleeve 63a is transported to a position facing the developing roll 62, and a part of the developer is replaced with the developer on the developing roll 62, thereby contributing to the next development.

In such a developing device, since the stirring roll 63 is separately provided as a developer stirring means, the toner concentration can be further uniformed. In this embodiment, a stirring roll 63 as a developer stirring means is used.
Was not opposed to the photosensitive drum 1, but the stirring roll 6
3 may be arranged to face the photosensitive drum 51.

FIG. 9 shows claims 1, 2, 3,
FIG. 21 is a schematic configuration diagram illustrating a developing device according to an embodiment of the invention described in claim 4, claim 5, claim 6, claim 19, or claim 21. The developing device includes a developing roller 7 that carries a two-component developer on a peripheral surface thereof in a housing 78 that accommodates the two-component developer and transports the two-component developer to a region facing the photosensitive drum 1.
2, a stirring roll 73 for transporting the developer to a position facing the developing roll 72 while mixing and stirring, and a blade 74 for breaking and damping a part of the ears of the two-component developer carried on the stirring roll 73. A guide member 74a integrated with the blade 74 for guiding the replenishment toner into contact with the developer whose ears are broken by the blade 74
And a toner conveying member 76 for conveying the toner 75 to the guide member 74a while loosening the stored toner.

As shown in FIG. 10, the developing roll 72 is formed by laminating a magnetic recording layer 72b on a conductive base 72a. A bias voltage is applied. In the magnetic recording layer 72b, S poles and N poles are alternately magnetized over the entire circumference of the developing roll 72. In this example, the magnetization pitch is 100 μm. By making the magnetic pole pitch minute in this manner, a substantially uniform developer layer can be formed without using a layer thickness regulating member. In the present embodiment, γ-Fe ₂ O ₃ is used as the magnetic material of the magnetic recording layer 72b and polyurethane is used as the binder resin, and the thickness of the magnetic recording layer 72b is 50 μm. A magnetic recording head was used to magnetize the magnetic recording layer 72b, and the direction of magnetization was horizontal to the peripheral surface of the developing roll 72 as shown in FIG.

Next, the magnetic recording layer 7 using the magnetic recording head
The magnetization of 2b will be described. The magnetization of the magnetic recording layer 72b is performed by a magnetic recording head 79 arranged close to the peripheral surface of the developing roll 72 as shown in FIG.

The magnetic recording head 79 includes a core member 79a made of a soft magnetic material and having both ends arranged side by side at intervals, and a coil 79c wound around the core 79b.
And the core 79 b is arranged such that both ends of the core 79 b are close to the peripheral surface of the developing roll 72. A magnetizing current is supplied from a power supply to the coil 79c via a magnetizing signal generator. When a current flows through the coil 79c, a magnetic flux 79d is generated in the core 79b. It passes through the magnetic recording layer 79b from the tip. Thereby, the magnetic recording layer 79b is magnetized. The magnetizing current supplied to the coil 79c is supplied intermittently or by changing the direction of the current intermittently via a magnetizing signal generator, and as shown in FIG. It is magnetized into a pattern. In the present embodiment, the developing roll 7
In the circumferential direction of No. 2, the N and S poles are alternately magnetized in a sine wave pattern, and the peak value of the magnetic flux density in the radial direction on the surface of the developing roll 72 is set to 50 mT. In the present embodiment, the diameter of the developing roll 72 is set to 15 mm, and 1 mm
It was rotated in the direction shown at 00 rpm.

The stirring roll 73 is composed of a rotatably supported hollow cylindrical non-magnetic conductive sleeve 73a and a magnetic field generating member 73b located inside the sleeve. The magnetic field generating member 73b is provided such that magnetic poles of different polarities are alternately magnetized over the entire circumference and can rotate independently of the outer sleeve 73a.

The sleeve 73a has an outer diameter of 24 mm.
And is formed of stainless steel. On the peripheral surface of the magnetic field generating member 73b, 25 magnetic poles are alternately magnetized with N poles and S poles at intervals of about 3 mm,
The maximum magnetic flux density (polar magnetic force) of each magnetic pole is 35 mT.

In this embodiment, the sleeve 73a is 10r
pm, and the magnetic field generating member 73b was rotated at 600 rpm in the directions shown. The structure of other members such as the blade 74 and the toner conveying member 75 of the developing device is shown in FIG.
Are the same as those used in the developing device shown in FIG. The carrier of the two-component developer used in this developing device is the same as the carrier used in the developing device shown in FIG.

In such a developing device, the developing roller 72
Is transported in the direction of the arrow, and reaches a position facing the stirring roller 73. In the area facing the stirring roll 73, the developing roll 7
2 is scraped off once by a magnetic brush which is moved by the rotation of the sleeve 73a and the magnetic field generating member 73b, and the new developer conveyed from the agitating roll 73 comes into contact with the developing roll 72 and the developing area. Transported to

The developer scraped off from the developing roll 72 is conveyed in the direction shown by the arrow while rotating on the stirring roll 73, guided to the toner supply area A, and a part of the ears is broken by the blade 74. In the toner supply area A,
The magnetic field acting on the developer whose ears have been broken is
Of the magnetic field generating member 73b.
For this reason, the developer in which the ears are broken vibrates in a state where the individual particles of the carrier are relatively dispersed. The toner 75 conveyed along the guide member 74a to the developer in this state.
When the toner is supplied, the toner 75 comes into contact with the exposed portion of the carrier surface, and the toner 75 is frictionally charged and electrostatically adheres to the carrier surface. Toner 7 already on carrier surface
The toner 75 in contact with the portion to which the toner 5 has adhered cannot be triboelectrically charged, and therefore does not adhere to the carrier.

Further, the toner 75 adhered to the carrier surface or the toner surface by non-electrostatic adhesion without frictional charging with the carrier is shaken off by the vibration of the developer due to the magnetic field of the magnetic field generating member 73b. Since the individual particles of the carrier are relatively dispersed by the blade 74, most of the surface of the carrier is covered with the toner 75 by passing through the toner supply area A only once. The developer supplied with the toner 75 is transported again to a position facing the developing roll 72, and a part of the developer is replaced with the developer on the developing roll 72, thereby contributing to the next development.

In such a developing device, a thin uniform developer layer is formed on the developing roll 72 without using a layer thickness regulating member. As a result, a high-speed and clear image can be stably obtained for a long period of time without imposing a large load on the developer.

FIG. 12 shows the invention according to claim 1, claim 2, claim 3, claim 4, claim 5, claim 6, claim 13, claim 14, claim 19 or claim 21. 1 is a schematic configuration diagram illustrating a developing device according to one embodiment. This developing device mixes and stirs the developer with a developing roll 82 that carries the two-component developer on its peripheral surface and conveys the developer to a region facing the photosensitive drum 1 in a housing 88 that stores the two-component developer. A stirring roll 83 which conveys the developer to a position opposed to the developing roll 82, and a developer damping portion 84 which temporarily damps a part of the bristles of the developer at the position opposed to the stirring roll 83 to form a toner supply area A And a toner conveying member 86 that supplies the toner 85 to the toner supply area A while loosening the stored toner in the toner storage section 87. Further, a magnetic member 89 is disposed on the downstream side of the developer stirring area A in the developer conveying direction on the stirring roll 83 so as to face the stirring roll 83. Although not shown, a toner box for replenishing the toner 85 is connected to an end of the toner container 77 in the axial direction.

The developing roll 82 and the stirring roll 83 are the same as those in the developing device shown in FIG. In the present embodiment, the interval between the developing roll 82 and the stirring roll 83 is set to 0.1 to 0.5 mm.

The developer damping portion 84 is formed integrally with the housing 88, and a developer stirring area A is formed at a position opposed to the housing 88. In the developer stirring region A, at least a part of the developer on the stirring roll 83 is dammed by the developer damping portion 84, and at least a part of the ears of the developer is broken. Due to the magnetic force of the magnetic field generating member 83b, a constantly changing magnetic field is formed, and individual particles of the carrier in the collapsed developer vibrate in a relatively dispersed state.

In the present embodiment, the distance between the stirring roll 83 and the developer damping portion 84 is 0.1 to 0.5 m.
m. The other structure of the developing device is the same as that of the developing device shown in FIG. The carrier of the two-component developer used in this developing device is the same as the carrier used in the developing device shown in FIG.

In such a developing device, the developing roll 82
After passing through the development area, the developer is transported in the direction of the arrow and reaches a position facing the stirring roller 83. At a position facing the stirring roll 83, the developing roll 8
2 is once scraped off by a magnetic brush of the developer on the stirring roll 83, and
The new developer carried from 3 is brought into contact with and carried by the developing roll 82 and is transported to the developing area. The developer scraped off from the developing roller 82 is conveyed in the direction shown by the arrow while rolling on the stirring roller 83, and is guided to the toner supply area A. In the toner supply region A, a part of the ears of the developer is broken by the developer damping portion 84, and the broken developer is caused by the fluctuating magnetic field generated by the rotation of the agitating roll 83, so that the individual carriers of the carrier are broken down. The particles oscillate in a relatively dispersed state.

The toner supply area A is replenished with the toner 85, mixed with the developer vibrating in a state of being relatively dispersed with the toner 85, and the toner 85 is supplied to the exposed portion of the carrier surface. Upon contact, the toner 85 is frictionally charged and electrostatically adheres to the carrier surface, and the toner 85 that has already contacted the portion of the carrier surface where the toner 85 has adhered cannot be frictionally charged and does not adhere to the carrier.

After passing through the toner supply area A, the developer supplied with the toner 85 is transported again to a position facing the developing roller 82 while rolling on the stirring roller 83, and a part of the developer is removed. In place of the developer on the developing roll 82, a developer layer serving as substantially one carrier layer is formed on the developing roll 82, and is used for the next development.

In such a developing device, the developer is appropriately rolled and agitated, so that the developer can be efficiently agitated in a state where the individual particles of the carrier are relatively dispersed, and the toner Uniform dispersion can be effectively performed. In addition, since a thin and uniform developer layer can be formed on the developing roll 82 without using a layer thickness regulating member, a clear image can be stably formed at a high speed for a long time without a large addition to the developer. Can be obtained.

FIG. 13 is a schematic structural view showing a developing device according to an embodiment of the present invention. The developing device includes a developing roll 92 that carries a two-component developer on a peripheral surface thereof and conveys the two-component developer to a region facing the photosensitive drum 1 in a housing 98 that accommodates the two-component developer; A developer damping portion 93 arranged to be in contact with the developer layer and damping a part of the developer to form a developer stirring area A; a magnet roll 94 arranged behind a wall surface of a housing 98; A toner transport member 9 that supplies toner 95 to the developer layer on the magnet roll 94 in the developer stirring area A while loosening the stored toner in the storage section 97.
6. Although not shown, a toner box for replenishing the toner 95 is connected to an end of the toner container 97 in the axial direction.

The magnet roll 94 is disposed behind the wall surface of the housing 98 so as to be close to the developing roll 92 at the developer damping portion 93. The magnet roll 94 has magnetic poles of different polarities alternately magnetized over the entire circumference and is rotatably supported.

A toner supply area A is formed at a position facing the developer damping portion 93. At least a part of the developer on the developing roll 92 is dammed by the developer damping portion 93, and the developer is stopped. At least a part of the spike is broken. Then, the toner in such a state is supplied with new toner by the toner conveying member 96, and is mixed and agitated. The other structure of the developing device is the same as that of the developing device shown in FIG. The carrier of the two-component developer used in this developing device is the same as the carrier used in the developing device shown in FIG.

In such a developing device, at least a part of the developer on the developing roll 92 is dammed in the developer damping portion 93, so that individual particles of the carrier in the developer are relatively dispersed. Housing 9
Due to the magnetic force of the magnet roll 94 and the developing roll 92 on the back surface of the developer 8, a constantly changing magnetic field is formed, and the individual particles of the carrier in the collapsed developer vibrate in a relatively dispersed state. Therefore, the developer in which the individual particles of the carrier are relatively dispersed can be efficiently stirred, and the effect of uniformly dispersing the supplied toner can be improved.

FIG. 14 is a schematic structural view showing a developing device according to an embodiment of the present invention. The developing device includes a developing roller 102 that carries a two-component developer on a peripheral surface thereof in a housing 108 that stores the two-component developer and conveys the two-component developer to a region facing the photosensitive drum 1.
And a magnet roll 103 as an opposing member that forms a developer stirring area B for mixing and stirring the developer at a position facing the developing roll 102, and at a position upstream of the developer stirring area B in the developer conveyance direction. , Toner storage unit 106
Toner transport member 105 that supplies toner 104 to the developer layer on magnet roll 103 while loosening the stored toner inside
And Although not shown, a toner box for replenishing the toner 104 is connected to an end of the toner container 106 in the axial direction.

The developing roll 102 comprises a hollow cylindrical non-magnetic conductive sleeve 102a rotatably supported and a magnetic field generating member 102b located inside the sleeve. The magnetic field generating member 102b has magnetic poles of different polarities alternately magnetized over the entire circumference and is fixed so as not to rotate. The outer diameter of the sleeve 102a is 18 mm
And is formed of stainless steel.

The developer on the developing roll 102 having the above-described structure is transported to the developing area facing the photosensitive drum 1 by the rotation of the sleeve 102a.

The magnet roll 103 is disposed close to and in contact with the developer layer on the developing roll 102, and magnetic poles of different polarities are alternately arranged over the entire circumference so as to carry and convey the developer on the peripheral surface. And is rotatably supported. In the present embodiment, the magnet roll 1
03 has an outer diameter of 23 mm, and the distance from the sleeve 102a is set to 0.1 to 0.5 mm.

The magnet roll 103 and the developing roll 1
A developer agitating region B is formed on the upstream side in the developer transport direction from the position where O.2 opposes. In the developer stirring area B, at least a portion of the developer on the magnet roll 103 and the ears of the developer on the development roll 102 are in a collapsed state, and the magnetic field generating member disposed inside the development roll 102 Due to the rotation of 102b and the magnet roll 103, a constantly fluctuating magnetic field is formed,
The individual particles of the carrier in the collapsed developer vibrate in a relatively dispersed state.

The toner conveying member 105 is rotated in the direction of the arrow shown in the figure in the toner container 106 to sufficiently agitate the toner and to replenish the toner supply port 1.
07 is carried around. The toner carried to the vicinity of the toner supply port 107 is supplied to the developer on the magnet roll 103 on the upstream side of the developer stirring area B in the developer transport direction. The other structure of this developing device is the same as that of the developing device shown in FIG. The carrier of the two-component developer used in this developing device is the same as the carrier used in the developing device shown in FIG.

In such a developing device, the developing roll 10
The developer carried on 2 is transported in the direction of the arrow and reaches the development area. A predetermined developing bias voltage is applied between the photoreceptor drum 1 and the developing roll 102, and an electric field is formed in a developing region where these are opposed to each other.
The toner is transferred from the developer on the photosensitive drum 1 to the photosensitive drum 1, and a toner image corresponding to the latent image is formed.

The developer that has passed through the developing area is guided to the developer stirring area B, and part of the ears of the developer on the developing roll 102 and the developer on the magnet roll 103 is broken. In the developer stirring area B, the magnetic field acting on the developer whose ears have broken is constantly fluctuating due to the rotation of the magnetic field generating member 102b and the magnet roll 103 arranged inside the developing roll 102. For this reason, the developer whose ears are broken is
The individual particles of the carrier are vibrating in a relatively dispersed state. The developer carried on the magnet roll 103 is:
The toner 104 is supplied from a supply port 107 provided on the upstream side of the developer stirring area B in the developer transport direction, and reaches the developer stirring area B.

In the developer stirring area B, the toner 104
The developer supplied on the magnet roll 103 is mixed with the developer on the developing roll 102 passing through the developing area, and vibrates in a state where the individual particles of the carrier are relatively dispersed. At this time, when the toner 104 comes into contact with the exposed portion of the carrier surface, the toner 104 is frictionally charged and electrostatically adheres to the carrier surface. Toner 104 that has already contacted a portion of carrier surface where toner 104 has adhered
Does not adhere to the carrier because it cannot be triboelectrically charged. Further, the toner 104 adhered to the carrier surface or the toner surface by non-electrostatic adhesive force without being frictionally charged with the carrier is shaken off by the vibration of the developer due to the magnetic field in the developer stirring area B. In the developer agitating region B, since the individual particles of the carrier are relatively dispersed, most of the surface of the carrier is covered with the toner 104, and the toner is uniformly dispersed. After passing through the developer stirring area B, the toner 1
The developer replenished with 04 is carried on the developing roll 102 and is again conveyed to the developing area facing the photosensitive drum 1.

In such a developing device, the developing roll 10
By disposing the magnet roll 103 and the magnet roll 103 close to each other, a developer stirring area B is formed, at least a portion of the developer spike is broken, and the magnetic field generating member 102b and the magnet roll 103 arranged in the development roll 102 are separated. Since the collapsed developer is stirred by the magnetic force, the surface area of the carrier is increased as compared with the state in which the developer is eared, and the number of times of contact with the toner is increased. As a result, the toner adheres to the surface of the carrier, but the toner having a weak adhesive force is sieved off by the stirring of the developer, so that a state in which the carrier can easily hold the toner can be created.

In the developing device, the sleeve 102
a was rotated to fix the magnetic field generating member 102b,
The magnetic field generation member 102b may be rotated to rotate in the same direction as the rotation direction of the sleeve 102a or in the opposite direction.

In the developing device having the above structure, the sleeve 102
Although a layer thickness regulating member that regulates the layer thickness of the developer on a is not used, when the thickness of the developer layer on the sleeve 102a varies, for example, the developer is regulated to achieve a desired layer thickness. To achieve this, a layer thickness regulating member may be added. in this case,
From the viewpoint of the life of the developer, it is desirable not to apply a large pressure to the developer. Thereby, a more uniform developer layer can be formed in the developing region.

FIG. 15 is a schematic structural view showing a developing device according to an embodiment of the present invention. The developing device includes a developing roller 112 that carries a two-component developer on a peripheral surface thereof and conveys the two-component developer to a region facing the photosensitive drum 1 in a housing 118 that stores the two-component developer. And a transport roll 113 which forms a developer stirring area B for mixing and agitating the developer in the vicinity of the opposite portion, and develops the toner 114 on the transport roll 113 in the developer agitating area B while loosening the stored toner. And a toner conveying member 115 for supplying the toner layer to the developer layer. Although not shown, a toner box for replenishing the toner 114 is connected to an end in the axial direction of the toner container 116 in which the toner conveying member 115 is disposed.

The developing roll 112 is formed by laminating a magnetic recording layer on a conductive substrate, and the developing bias voltage is applied to the conductive substrate by a developing bias power supply (not shown). Also, the developing roll 11 is provided on the magnetic recording layer.
The S pole and the N pole are alternately magnetized over the entire circumference of No. 2, and in this example, the magnetization pitch is 100 μm.
By reducing the magnetic pole pitch in this manner, it is possible to form a substantially thinner layer of the developer, which becomes a carrier layer, without using a layer thickness regulating member.

In this embodiment, γ-Fe ₂ O ₃ is used as the magnetic material of the magnetic recording layer and polyurethane is used as the binder resin, and the thickness of the magnetic recording layer is 50 μm. A magnetic recording head was used to magnetize the magnetic recording layer, and the direction of magnetization was horizontal to the peripheral surface of the developing roll 112. In the present embodiment, the N and S poles are alternately magnetized in a sine wave pattern in the circumferential direction of the developing roll 112, and the peak value of the magnetic flux density in the radial direction on the surface of the developing roll 112 is set to 50 mT. . The developing roller 112 has a diameter of 15 mm and is rotated at 100 rpm in the direction shown.

The transport roll 113 comprises an outer member 113a, which is a rotatably supported hollow cylindrical non-magnetic conductive sleeve, and an inner member 113b, which is a magnetic field generating member located inside the outer member 113a. . The inner member 113b is provided such that magnetic poles of different polarities are alternately magnetized over the entire circumference and can rotate independently of the outer member 113a.

In this embodiment, the outer diameter of the outer member 113a is 23 mm, the distance between the outer member 113a and the developing roll 112 is set to 0.1 to 0.5 mm, the outer member 113a is The member 113b is 60
Each is rotated in the illustrated direction at 0 rpm.

The transport roll 113 and the developing roll 1
A developer agitating region B is formed on the upstream side in the developer conveying direction from a position where the developer agitating portion 12 faces. In the developer stirring area B, since the developing roll 112 which is an opposing member is disposed close to the transport roll 113, at least a portion of the developer ears on the transport roll 113 is broken. By rotating the internal member 113b of the transport roll 113, a constantly fluctuating magnetic field is formed, and the individual particles of the carrier in the collapsed developer vibrate in a relatively dispersed state. . The other structure of the developing device is the same as that of the developing device shown in FIG. The carrier of the two-component developer used in this developing device is the same as the carrier used in the developing device shown in FIG.

In such a developing device, the developing roll 11
After being carried by the developer 2 and passing through the developing area, the developer is transported in the direction of the arrow and reaches the developer stirring area B. In the developer stirring area B, the developer sent from the developing roll 112 is once scraped by a magnetic brush which is moved by rotation of the outer member 113a and the inner member 113b of the transport roll 113. The developer transported on the transport roll 113 is transferred to the developing roll 112 which is an opposing member.
As a result, at least a part of the ears is broken. In the developer stirring area B, the transport roll 113
Due to the rotation of the internal member 113b, a constantly fluctuating magnetic field is formed, so that the developer scraped off from the developing roll 112 and the individual particles of the carrier of the broken developer on the transport roll 113 are relatively dispersed. It is vibrating in the state where it was done.

Since the toner 114 is supplied to the developer stirring area B, the toner 114 and the developer are mixed, and when the toner 114 comes into contact with the exposed portion of the carrier surface, the toner 114 is frictionally charged. Electrostatically adheres to the carrier surface, and the toner 114
The toner 114 in contact with the portion to which the toner has adhered cannot be triboelectrically charged and does not adhere to the carrier.

The developer replenished with the toner 114 is replaced by the developer scraped off from the developing roll 112, and the developer layer serving as a substantially carrier layer is replaced with the developing roll 112.
It is formed on the top and contributes to the next development.

In such a developing device, a thin and uniform developer layer is formed on the developing roll 112 without using a layer thickness regulating member. As a result, a high-speed and clear image can be stably obtained for a long period of time without imposing a large load on the developer.

FIG. 16 is a schematic configuration diagram showing a developing device according to an embodiment of the invention described in claim 23, claim 24, claim 26, claim 27, claim 28 or claim 29. The developing device includes a housing 128 containing a two-component developer, a developing roller 122 that carries the two-component developer on the peripheral surface and transports the two-component developer to a region facing the photosensitive drum 1,
A transport roll 123 is disposed at a position facing the developing roll 122 and forms a developer stirring area B for mixing and stirring the developer, and a developer supply area B for releasing the toner 124 while loosening the stored toner. And a toner transporting member 125 for supplying the developer layer carried on the transporting roll 123. Although not shown, a toner box for replenishing toner 124 is connected to an end in the axial direction of the toner container 126 in which the toner conveying member 125 is disposed.

The transport roll 123 is disposed so as to be in close contact with the developer layer on the developing roll 122, and is a hollow cylindrical non-magnetic conductive sleeve rotatably supported. And an internal member 123b as a magnetic field generating means located inside. The inner member 123b has about 5 magnetic poles of different polarities.
mm, and the maximum magnetic flux density (polar magnetic force) of each magnetic pole is about 50 mT.
It is provided so that it can rotate independently of a. In the present embodiment, the outer diameter of the outer member 123a is 2
3 mm, the external member 123a and the developing roll 12
2 is set to 0.1 to 0.5 mm, and the external member 1
23a is 10 rpm, internal member 123b is 600 rpm
Are rotated in the directions shown in FIG.

The transport roll 123 and the developing roll 1
A developer agitating area B is formed on the upstream side in the developer transport direction from the position facing 22. In the developer stirring area B, since the transport roll 123 and the development roll 122 are arranged close to each other, at least a part of the ears of each developer is broken, and the development roll 122 and the transport roll 123 are displaced. A constantly changing magnetic field is formed by the internal member 123b, so that the individual particles of the carrier in the collapsed developer vibrate in a relatively dispersed state. The other structure of the developing device is the same as that of the developing device shown in FIG.
The carrier of the two-component developer used in this developing device is the same as the carrier used in the developing device shown in FIG.

In such a developing device, the transport roll 12
3 has a double structure of an outer member 123a and an inner member 123b, and by rotating the inner member 123b, which is a magnetic field generating member, in the developer stirring area B, the variation of the magnetic field acting on the developer with broken ears is reduced. Since the cycle can be made smaller, the individual particles of the carrier in the developer can be stirred in a more dispersed state. Therefore, the effect of uniformly dispersing the toner can be improved.

[0179]

As described above, in the developing device according to the present invention, the carrier particles are relatively dispersed by breaking a part of the ears of the developer near the developer stirring section. In the area where the developer collapses, the replenishment toner and the developer are agitated, and the toner is attracted by contact with the magnetic carrier, and at the same time, the toner having a small adhesive force with the magnetic carrier can be sieved off. It is possible to hold toner near the limit amount that can be carried. For this reason, the toner density and charge amount of the developer conveyed to the developing area can be maintained substantially uniform, and a stable image density can be obtained for a long period of time. Further, a complicated toner density control means as in the related art is not required, so that the cost can be reduced and the size of the apparatus can be reduced, and the developing apparatus can accommodate a relatively small amount of developer. Further, even when applied when forming a color image, stable and favorable development can be performed.

[Brief description of the drawings]

FIG. 1 is a schematic view showing a developing device according to an embodiment of the invention described in claim 1, claim 2, claim 3, claim 4, claim 5, claim 6, claim 19, or claim 20; It is a block diagram.

FIG. 2 is a diagram illustrating a toner concentration and a toner charge amount in each process of the developing device.

FIG. 3 is a schematic configuration diagram showing a developing device according to an embodiment of the present invention described in claim 1, 19, or 20;

FIG. 4 is a block diagram showing an embodiment of the present invention; FIG.
21 is a schematic configuration diagram illustrating a developing device according to an embodiment of the present invention.

FIG. 5 is a plan view of the first embodiment of the present invention; FIG.
21 is a schematic configuration diagram illustrating a developing device according to an embodiment of the present invention.

FIG. 6 is an embodiment of the invention according to claim 1, claim 2, claim 3, claim 4, claim 5, claim 6, claim 12, claim 19 or claim 20. It is a schematic structure figure showing an apparatus.

FIG. 7 is a block diagram showing a configuration of a first embodiment of the present invention;
FIG. 19 is a schematic configuration diagram illustrating a developing device according to an embodiment of the present invention.

FIG. 8 is a view showing a state in which the first embodiment of the present invention is used;
6, Claim 17, Claim 18, Claim 19 or Claim 2
1 is a schematic configuration diagram illustrating a developing device according to an embodiment of the invention described in FIG.

FIG. 9 is a schematic diagram showing a developing device according to an embodiment of the invention described in claim 1, claim 2, claim 3, claim 4, claim 5, claim 6, claim 19, or claim 21; It is a block diagram.

FIG. 10 is an enlarged sectional view showing a magnetic recording layer of a developing roll used in the developing device.

FIG. 11 is an explanatory diagram showing an example of a method of magnetizing a magnetic recording layer of a developing roll used in the developing device.

FIG. 12 is a plan view of the first embodiment;
FIG. 17 is a schematic configuration diagram showing a developing device according to an embodiment of the invention described in claim 5, claim 6, claim 13, claim 14, claim 19, or claim 21.

FIG. 13 is a schematic configuration diagram showing a developing device according to an embodiment of the present invention.

FIG. 14 is a schematic configuration diagram showing a developing device according to an embodiment of the invention described in claim 23 or 24.

FIG. 15 is a schematic configuration diagram showing a developing device according to an embodiment of the invention described in claim 23, claim 24 or claim 25.

FIG. 16 is a schematic configuration diagram showing a developing device according to an embodiment of the invention described in claim 23, claim 24, claim 26, claim 27, claim 28 or claim 29.

FIG. 17 is a schematic configuration diagram illustrating an example of a conventional developing device.

FIG. 18 is a diagram illustrating a relationship between a toner density and a toner charge amount in a conventional developing device.

FIG. 19 is a diagram showing a result of investigation on a relationship between a magnetic pole pitch or a developer layer thickness and a stirring state of a developer.

[Description of Signs] 1 Photoconductor drum 2, 12, 22, 32, 42, 52, 62, 72, 8
2, 92 Development rolls 2a, 22a, 32a, 42a, 52a, 92a Sleeves 2b, 22b, 32b, 42b, 52b, 92b Magnetic field generating members 3, 13, 23, 33, 43, 64, 74 Blades (damping members) 3a , 64a, 74a Guide members 4, 14, 24, 34, 44, 54, 65, 75, 8
5, 95 Toner 5, 15, 25, 35, 45, 55, 66, 76, 8
6, 96 Toner transport member 6, 16, 26, 36, 46, 56, 67, 77, 8
7, 97 Toner container 7, 17, 27, 37, 47, 57, 68, 78, 8
8, 98 Housing 28 Vibration member 38 Electrode member 39 AC power supply 48 Frame 49 Vibration member 58, 89 Magnetic member 63, 73, 83 Stirring roll 63a, 73a, 83a Sleeve 63b, 73b, 83b Magnetic field generating member 72a Conductivity Base 72b Magnetic recording layer 84, 93 Developer damping portion 94 Magnet roll 102, 112, 122 Developing roll 102a, 122a Sleeve 102b, 122b Magnetic field generating member 103 Magnet roll 104, 114, 124 Toner 105, 115, 125 Toner transport member 106, 116, 126 Toner container 107 Toner supply port 108, 118, 128 Housing 113, 123 Transport rolls 113a, 123a External member 113b, 123b Internal member

──────────────────────────────────────────────────続 き Continued on front page (51) Int.Cl. ⁶ Identification code FI G03G 15/08 507 G03G 15/08 507E

Claims (29)

[Claims] 1. A two-component developer containing a magnetic carrier and a toner electrically adsorbed on the magnetic carrier,
In a developing device for selectively transferring the toner to an electrostatic latent image formed on an image carrier and visualizing the toner, a portion that rotates independently or integrally with an endless peripheral surface includes the peripheral surface. A plurality of magnetic poles are magnetized along, the two-component developer is adsorbed on the peripheral surface by these magnetic poles, and the magnetic carrier forms a spike-shaped developer layer, and the plurality of magnetic poles are formed. A developer transporting member that transports the two-component developer by orbital movement or movement of the peripheral surface; and dams at least a part of a chain of the two-component developer layer carried on the developer transporting member. A developer agitating section for agitating the two-component developer in a region of the developer transport member where a magnetic attraction force is applied; and a two-component developer in the developer agitating section, wherein the magnetic carrier is electrically charged. Almost limit amount that can be adsorbed Developing apparatus is characterized in that the toner supply and is provided for supplying toner. 2. The developing device according to claim 1, wherein the developer transport member has an S pole and an N pole alternately magnetized over the entire periphery of the endless peripheral surface. An inner member supported rotatably; and an endless outer peripheral member supported outside the outer peripheral surface of the inner member, wherein the inner member is stationary or orbitally driven on an outer peripheral surface of the outer peripheral member. The two-component developer magnetically adsorbed to
A developing device which is conveyed on the outer peripheral member and driven to rotate so as to cause rolling and agitation of the two-component developer layer in a spike shape. 3. The developing device according to claim 2, wherein the magnetic poles of the internal member are magnetized such that a magnetic pole interval P satisfies 0.12 mm ≦ P ≦ 6 mm. The strength of the magnetic pole, or the amount of the entire developer and the amount of damping of the developer in the developer agitating section are set so that the layer thickness D of the two-component developer adsorbed thereon becomes D ≦ P / 3. A developing device. 4. The developing device according to claim 2, wherein a magnetic flux density B of each magnetic pole of the internal member satisfies 10 mT ≦ B ≦ 100 mT. 5. The developing device according to claim 2, wherein the carrier in the two-component developer has a particle size R of 10 μm ≦ R ≦ 80 μm, and 10 ⁶ / (4π) A developing device, wherein the magnetization J in a magnetic field of A / m is 45 kA / m ≦ J ≦ 360 kA / m. 6. The developing device according to claim 1, wherein the developing device is disposed so as to face the developer conveying member with a gap therebetween. A developing device comprising: a damming member for breaking and damping a part of a chain of developer formed on a developer conveying member; and an upstream side of the damming member is the developer stirring section. . 7. The developing device according to claim 6, wherein the dam member is at least partially formed of a magnetic material. 8. The developing device according to claim 6, wherein the dam member has a magnet. 9. The developing device according to claim 6, further comprising: vibrating means for vibrating the dam member. 10. The developing device according to claim 9, wherein said vibrating means is provided so as to come into contact with said dam member, and mechanically vibrates said dam member. apparatus. 11. The developing device according to claim 9, wherein the vibrating means is an electrode member provided to face the dam member, and an AC voltage is applied between the dam member and the dam member. Characteristic developing device. 12. The developing device according to claim 6, further comprising a vibration member that vibrates in contact with the developer blocked by the dam member. 13. The developing device according to claim 6, wherein the developing device is provided on the developer transporting member, downstream of the dam member in the developer transporting direction and in close proximity to the developer transporting member. A developing device having a stirring means for stirring the two-component developer carried on the developer conveying member. 14. The developing device according to claim 13, wherein said stirring means is a magnetic member disposed to face a peripheral surface of said developer conveying member with a gap therebetween. 15. The developing device according to claim 13, wherein the agitating means is configured such that S poles and N poles are alternately magnetized over the entire periphery of the endless peripheral surface, and the peripheral surface is rotatable. And an endless outer peripheral member supported outside the outer peripheral surface of the inner member. The outer peripheral member is magnetically attracted to the outer peripheral surface of the outer peripheral member which is stationary or driven to rotate. The two-component developer is conveyed on the outer peripheral member, and the inner member is driven to rotate so that rolling and agitation of the spike-shaped two-component developer layer occur. Developing device. 16. The developing device according to claim 15, wherein the magnetic poles of the internal member are magnetized so that a magnetic pole interval P satisfies 0.12 mm ≦ P ≦ 6 mm, and the magnetic poles are formed on the sleeve. The strength of the magnetic pole, or the amount of all the developer and the amount of damping of the developer in the developer agitating section are set so that the layer thickness D of the two-component developer adsorbed on the developer satisfies D ≦ P / 3. A developing device. 17. The developing device according to claim 15, wherein a magnetic flux density B of each magnetic pole of the internal member satisfies 10 mT ≦ B ≦ 100 mT. 18. The method of claim 15, claim 16 or claim 1.
7. The developing device according to 7, wherein the carrier in the two-component developer has a particle size R of 10 μm ≦ R ≦ 80 μm and a magnetization J in a magnetic field of 10 ⁶ / (4π) A / m of 45 kA. / M ≦ J ≦ 360 kA / m 2. 19. The developing device according to claim 1, wherein the developer agitating unit is configured to perform development on the developer conveying member. A developing device provided at a position where the agent is conveyed in the direction of action of gravity. 20. The developing device according to claim 1, wherein the developer transport member is in close proximity to the image carrier. Wherein the toner in the two-component developer is transferred to an electrostatic latent image on the image carrier. 21. The developing device according to claim 1, 2, 3, 4, 5, or 6, wherein the developing device is disposed so as to be in close proximity to the image carrier, and is driven to rotate. The developing member has a developing member magnetized at intervals so as to adsorb substantially one carrier layer on the circumferential surface to be formed, wherein the S pole and the N pole alternately adsorb the carrier layer. A developing device, wherein the developing device is disposed in the developing device. 22. Using a two-component developer containing a magnetic carrier and a toner electrically attracted to the magnetic carrier, selectively transferring the toner to an electrostatic latent image formed on an image carrier. A developing device that magnetically adsorbs the two-component developer on an endless peripheral surface to form a developer layer in which the magnetic carrier has a spike shape, and conveys the developer along the peripheral surface. A developer agitating section having at least a portion of the spike-shaped chain of the two-component developer carried on the developer transporting member being dammed and staying; A toner supply unit that supplies a substantially limit amount of toner capable of electrically adsorbing the magnetic carrier to a certain two-component developer is provided. The toner supply unit is disposed behind a wall surface of a housing surrounding the developer stirring unit, and is rotationally driven. The developer stirring section A developing device, wherein a magnet to form a variable magnetic field is provided. 23. Using a two-component developer containing a magnetic carrier and a toner electrically attracted to the magnetic carrier, selectively transferring the toner to an electrostatic latent image formed on an image carrier. A first developer transport member having an endless peripheral surface, magnetically adsorbing the two-component developer on the peripheral surface and transporting the developer in a peripheral direction; Has an endless peripheral surface that is close to and opposes the developer transport member, magnetically adsorbs the two-component developer on this peripheral surface, and is located at a position facing the first developer transport member. A second developer transport member that transports a two-component developer in the same direction as the first developer transport member, wherein the first developer transport member and the second developer transport member A part of the two-component developer conveyed on the peripheral surfaces of both developer conveying members is blocked upstream of the opposing position of A plurality of magnetic poles magnetized along a peripheral surface of at least one of the first developer conveying member and the second developer conveying member. The developing device is characterized in that the developing device is moved so that the attraction force of the fluctuating magnetic field generated by the moving device is applied to the two-component developer in the developer stirring section. 24. The developing device according to claim 23, wherein one of the first developer transport member and the second developer transport member is disposed in close proximity to the image carrier, A developing device for transferring a toner in a two-component developer to the image carrier. 25. The developing device according to claim 23, wherein one of the first developer transport member and the second developer transport member has an S pole and an N pole on a peripheral surface that is driven to rotate. Are alternately magnetized at an interval that adsorbs almost one carrier layer, and the peripheral surface is arranged so as to closely approach the image carrier, so that the toner in the two-component developer is applied to the image carrier. A developing device for transferring. 26. The developing device according to claim 23, wherein at least one of the first developer transport member and the second developer transport member covers the entire periphery of an endless peripheral surface. An S-pole and an N-pole are alternately magnetized, and have an inner member whose peripheral surface is driven to rotate, and an endless outer member supported outside the peripheral surface of the inner member. The two-component developer magnetically adsorbed on the outer peripheral surface of the driven outer peripheral member is transported on the outer peripheral member, and rolling and stirring of the spike-shaped two-component developer layer occur. A developing device wherein the internal member is driven to rotate. 27. The developing device according to claim 26, wherein the magnetic poles of the internal member are magnetized so that a magnetic pole interval P is 0.12 mm ≦ P ≦ 6 mm, and the magnetic poles are formed on the sleeve. The strength of the magnetic pole, or the amount of all the developer and the amount of damping of the developer in the developer agitating section are set so that the layer thickness D of the two-component developer adsorbed on the developer satisfies D ≦ P / 3. A developing device. 28. The developing device according to claim 26, wherein a magnetic flux density B of each of the magnetic poles of the internal member satisfies 10 mT ≦ B ≦ 100 mT. 29. Claim 26, Claim 27 or Claim 2
8. The developing device according to 8, wherein the carrier in the two-component developer has a particle size R of 10 μm ≦ R ≦ 80 μm and a magnetization J in a magnetic field of 10 ⁶ / (4π) A / m of 45 kA. / M ≦ J ≦ 360 kA / m 2.