JP2002139914A - Developing device, image forming device and process cartridge - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a developing device, an image forming device and a process cartridge capable of preventing a white stripe from occurring on a toner image due to the accumulation of developer before a developer regulating member. SOLUTION: The end 6a of the 1st doctor 6 of this developing device 100 is arranged on the more downstream side of a developing sleeve 4 in a developer feeding direction than the perpendicular apex position of the sleeve 4. Thus, the developer 3 carried and fed by the sleeve 4 obtains feeding force by its own gravity before the 1st doctor 6, and is fed without being accumulated before the 1st doctor 6.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a developing device, an image forming apparatus, and a process cartridge used for an image forming apparatus such as a copying machine, a facsimile, a printer, and the like. More specifically, the present invention relates to a method for forming a latent image formed on an image carrier. A developing device having a function of maintaining the toner concentration of the developer at a predetermined concentration by self-controlling the toner concentration of a two-component developer including a toner to be developed and magnetic particles, an image forming apparatus including the developing device, And an image carrier, and at least one unit selected from a charging unit, a developing unit including the developing device, and a cleaning unit are integrally supported and detachably attached to the image forming apparatus main body. It relates to a process cartridge.

[0002]

2. Description of the Related Art Conventionally, as a developing device used in an image forming apparatus such as an electrophotographic copying machine, a facsimile, a printer, etc., a two-component developing device comprising a toner for developing a latent image formed on an image carrier and magnetic particles is used. 2. Description of the Related Art A developing device of a toner concentration self-control type having a function of self-controlling the toner concentration of a developer and maintaining the toner concentration of the developer at a predetermined concentration is known (Japanese Patent Application Laid-Open No. 9-197833, Wish 20
00-299647).

FIG. 6 shows an example of this type of developing device of the toner concentration self-control type. The developing device 100 includes a developing casing 2 which is provided on a side of a cylindrical photosensitive drum 1 serving as an image carrier and has an opening 2a formed so as to face the photosensitive drum 1. ing. In the developing casing 2, a developing sleeve 4 made of a non-magnetic material as a developer carrying member that carries a developer 3 made of toner and magnetic particles (carrier) on a surface is partially exposed through the opening 2 a. Thus, it is rotatably disposed so as to rotate in the direction of the arrow in FIG. Inside the developing sleeve 4, a magnet roller 5 having a plurality of magnetic poles formed on a peripheral surface as a fixed magnetic field generating means is fixedly arranged.

In the developing casing 2, a first developer regulating member for regulating the layer thickness of the developer 3 carried and conveyed by the developing sleeve 4 toward the opening 2a is provided. A doctor 6 is disposed so as to close the upper opening 2 a of the developing casing 2. The first
The end 6a of the doctor 6 is substantially perpendicular to the surface of the developing sleeve 4 and has a predetermined gap between the end 6a of the first doctor 6 and the surface of the developing sleeve 4. Developer 3 carried and conveyed by the developing sleeve 4
To determine the layer thickness).

Further, a developer accommodating portion 7 for accommodating the developer 3 scraped off by the first doctor 6 is formed in the developing casing 2. This developer container 7
Is provided with a stirring roller 9 made of a magnetic member that rotates in the same direction as the rotation direction of the developing sleeve 4. The developer casing 2 includes the developer container 7.
A second doctor 8 as a second developer regulating member for regulating the amount of the developer 3 carried and conveyed by the developing sleeve 4 toward the developing sleeve 4 has a developer inlet 10 into the developer accommodating section 7. And a toner supply path 1 into the developing casing 2
1 are formed.

Further, a toner 12 to be supplied toward the developing sleeve 4 through the toner supply path 11 is provided at a portion of the developing casing 2 opposite to the photosensitive drum 1.
Is disposed. The toner hopper 13 has an agitator 1 for stirring and transporting the toner 12 stored in the toner hopper 13.
4 are provided. In a portion of the toner hopper 13 facing the toner supply path 11 of the developing case 2, a toner supply port for discharging the toner 12 stirred and conveyed by the rotation of the agitator 14 toward the toner supply path 11. 15 are formed.

Here, when the developing device 100 is not used, the toner supply port 15 of the toner hopper 13 is sealed to prevent the toner 12 in the toner hopper 13 from leaking from the toner supply port 15. Member 16
Sealed. When the developing device 100 is used, the operator peels off the seal member 16 and opens the toner supply port 15, so that the toner in the toner hopper 13 passes through the toner supply port 15 and the toner supply path 11. 12 is taken into the developing case 2.

When the developing device 100 is not used, the developer 3 is contained in a developer case 17 which is detachably provided on the upper portion of the developing casing 2. A developer supply port 1 for discharging the developer 3 in the developer case 17 toward the developer storage portion 7 is provided in a portion of the developer case 17 facing the developer storage portion 7.
The developer supply port 18 of the developer case 17 is sealed by a seal member 19 when not in use. When the developing device 100 is used, the operator peels off the seal member 19 and opens the developer supply port 18 so that the developer is accommodated in the developer case 17 through the developer supply port 18. The developer 3 is stored in the developer storage section 7 of the developing case 2.

FIG. 7 shows the developing device 100 in a state where the developer 3 of the developer case 17 is housed in the developer housing portion 7 of the developing case 2 as described above. In FIG. 7, the toner 12 sent out from the inside of the toner hopper 13 by the rotation of the agitator 14 passes through the toner supply port 15 of the toner hopper 13 and the toner supply path 11 of the developing casing 2 and passes through the developing sleeve 4. The developer is supplied to the developer carried on the developing device, and is conveyed to the developer accommodating section 7. The developer 3 in the developer accommodating section 7 is carried and conveyed by the developing sleeve 4 to be thinned to a predetermined layer thickness by the first doctor. Is conveyed toward a position (developing site) opposite to. Then, at the development site, only the toner 12 in the developer 3 is electrostatically coupled to the electrostatic latent image formed on the photosensitive drum 1 in advance, so that the toner 12 A toner image is formed.

Here, when the developer 3 that is being rotated by the rotation of the developing sleeve 4 passes through the developer accommodating section 7, it is braked by the developer remaining in the developer accommodating section 7. Can be applied. As a result, the transport speed of the developer 3 decreases, and the layer thickness of the developer on the developing sleeve 4 near the second doctor 8 increases. Then, the toner 1 from the toner supply port 15 of the toner hopper 13 is
When the toner concentration of the developer 3 increases due to the intake of 2, the frictional force between the developers decreases. As a result,
The transport speed of the developer 3 is further reduced, the layer thickness of the developer 3 is further increased, and the second doctor 8 prevents the developer 3 from advancing. Then, in such a state, the toner supply path 11 of the developing casing 2 is changed.
Is blocked by the staying developer that has been prevented from progressing, and the toner 12 from the toner supply port 15 of the toner hopper 13 is
Import stops.

On the other hand, on the contrary, when the toner concentration of the developer 3 decreases due to the consumption of toner accompanying the formation of the toner image, the frictional force between the developers increases. As a result, the developer flowing along with the developing sleeve 4 for taking in the stagnant developer into the developer accommodating section 7 comes into contact with the toner in the toner supply path 11, and the toner supply path 11 stays in the developing casing 2
Is taken in. By the above operation, the toner concentration of the developer 3 contained in the developer containing section 7 is automatically controlled.

In FIG. 7, the developer 3 in which the electrostatic latent image formed on the photosensitive drum 1 is converted into a toner image and the toner is consumed is further conveyed as the developing sleeve 4 rotates. The developer merges with the developer whose progress is regulated by the second doctor 8. Here, the layer of the developer carried and transported by the developing sleeve 4 is referred to as a movable layer, and the layer of the developer whose progress is regulated by the second doctor 8 is referred to as an immobile layer.

The developer in the movable layer is further conveyed with the rotation of the developing sleeve 4 so as to enter under the developer in the immobile layer. At the boundary between the developer of the movable layer and the developer of the immobile layer, the toner supply path 1
The toner 12 sent into the developing casing 2 through 1 contacts the developer in the movable layer. Then, the developer 3 that has passed through the second doctor 8 is transported into the developer accommodating section 7 through the developer intake port 10.

Here, since the stirring roller 9 and the developing roller 4 are both rotating in the same direction, the rotation direction of each peripheral surface is opposite at the opposing portion between the stirring roller 9 and the developing roller 4. different. Thereby, the developing sleeve 4
The developer 3 carried and conveyed is separated from the peripheral surface of the developing sleeve 4 at an opposing portion between the stirring roller 9 and the developing roller 4. The separated developer 3 is conveyed to the first doctor 6 side along the rotation direction of the stirring roller 9 and again carried by the developing sleeve 4 under the influence of the magnetism of the magnet roller 5. Conveyed.

[0015]

By the way, in this type of developing device, as shown in FIG. 7, the rotation of the developing sleeve 4 causes the developing portion 4 to face a developing portion which is a portion facing the photosensitive drum 1. The progress of excess developer among the developer 3 carried and transported is stopped by the first doctor 6. As a result, the excess developer scraped off by the first doctor 6 stays at the portion of the developer accommodating portion 7 on the upstream side of the first doctor 6 in the developer transport direction, and the developer staying portion A is formed. Is done. Further, the developer scraped off from the developing sleeve 4 by the rotation of the stirring roller 9 also stays in the developer accommodating portion 7 to form a developer staying portion B.

When such a developer stagnation section, particularly the developer stagnation section A, is formed, the developer accumulated in the developer stagnation section A is coagulated and solidified by the influence of temperature and the like, and The gap between the first doctor 6 and the developing sleeve 4 may be closed. As a result, the flow of the developer 3 contained in the developer containing section 7 is obstructed, and white stripes are generated on the toner image.

Therefore, the present inventors conducted a magnetic flux analysis of the magnet roller 5. As a result, it became clear that the developer stagnation portion A was formed under the influence of the magnetic force component of the magnet roller 5. That is, as in the case of a general magnetic brush developing type developing device, a first magnetic pole N1 as a main pole formed so as to face the developing site is provided on the peripheral surface of the magnet roller 5, A second magnetic pole S1 formed to face the stirring roller 9;
A third magnetic pole N2 and a fourth magnetic pole S2 are formed to allow the developer 3 to be transported while being continuously carried on the developing sleeve 4. The magnetic force component of the magnet roller 5 includes normal magnetic forces P1, P2 and P2 having a function of raising the developer 3 on the developing sleeve 4 as shown in FIG.
P3, P4, and tangential magnetic forces P1 ', P2', P3 ', P4' having the function of causing the developer 3 on the developing sleeve 4 to rotate with the rotation of the developing sleeve 4 as shown in FIG. Have been.

FIG. 8 is a diagram in which the normal magnetic flux density measured by performing magnetic flux analysis on the single magnet roller 5 is superimposed on the developing device 2. FIG. 9 is a diagram in which the tangential magnetic flux density measured by magnetic flux analysis of the same magnet roller 5 is superimposed on the developing device 2. The normal magnetic flux and the tangential magnetic flux are components that are opposite to each other. The transport force of the developer 3 is large in a portion where the tangential magnetic force is strong, and the transport force of the developer 3 is small in a portion where the normal magnetic force is strong.

As described above, in this type of developing device, the tangential magnetic force of the magnet roller 5 at the portion of the first doctor 6 is weakened. It has been clarified that the sheets are conveyed while passing through the gap between the first doctor 6 and the developing sleeve 4 while being stacked. Therefore, in this type of developing device, the conveying force of the developer 3 on the developing sleeve 4 is almost lost before the first doctor 6, so that the developer 3 regulated by the first doctor 6 is not used. Under the influence of the normal magnetic force of the magnet roller 5, the developer accumulates in a portion in front of the first doctor 6, thereby forming the developer retaining portion A. When such a developer stagnation portion A is formed, the developer accumulated in the developer stagnation portion A is agglomerated and solidified under the influence of temperature or the like, and the first doctor 6 and the developing sleeve 4 Is closed, and the flow of the developer 3 contained in the developer containing section 7 is obstructed,
White stripes occur on the toner image.

Further, when the agitation roller 11 is disposed near the developing sleeve 4 and the magnetic flux analysis of the same magnet roller 5 is performed, the magnetic flux component of the magnet roller 5 is determined by the method shown in FIG. Linear magnetic force P1, P2, P3, P
4 and tangential magnetic forces P1 ', P2', P as shown in FIG.
It was found that 3 ′, P4 ′ and the normal magnetic force of FIG. 10 were obtained.
As a result, in the developing device having the configuration in which the stirring roller 11 is disposed near the developing sleeve 4, the transport component (tangential magnetic force) of the developer 3 at the first doctor 6 is
As shown in FIG. 11, it was found that the magnetic force of the stirring roller 9 weakened. For this reason, in such a developing device, the developer 3 pumped up by the stirring roller 9 hits the first doctor 6 before arriving at the developing sleeve 4 by the rotational force of the stirring roller 9 and stalls. The toner image falls on the developing sleeve 4 and is conveyed, and the generation of white stripes on the toner image becomes more remarkable.

The present invention has been made in view of the above problems, and has as its object to reduce the occurrence of white stripes on a toner image due to accumulation of developer in front of a developer regulating member. It is an object of the present invention to provide a developing device, an image forming apparatus, and a process cartridge which can prevent the occurrence of the developing device.

[0022]

In order to achieve the above object, the invention of claim 1 has a fixed magnetic field generating means inside, and carries and transports a two-component developer containing a toner and a magnetic carrier. Developer carrying member, a developer regulating member for regulating the amount of developer carried and carried by the developer carrying member, and a developer accommodating container for accommodating the developer scraped off by the developer regulating member And a toner accommodating section for accommodating a toner to be supplied to the developer carrier, and a state of contact between the developer and the toner due to a change in the toner concentration of the developer on the developer carrier. In the developing device having the function of maintaining the toner concentration of the developer at a predetermined concentration by self-controlling the amount of toner taken in from the toner storage section by changing The end of the developer regulating member is Than the vertical top position of the carrier, it is characterized in that disposed in the developer conveyance direction downstream side of the developer carrying member.

In this developing device, the end of the developer regulating member is located downstream of the vertical apex position of the cylindrical developer carrier in the developer conveying direction. Are located. As a result, the developer carried and conveyed by the developer carrying member obtains a conveying force due to its own weight before the developer regulating member and accumulates in front of the developer regulating member. Without being transported.

According to a second aspect of the present invention, there is provided a developer carrying member having a fixed magnetic field generating means therein for carrying and transporting a two-component developer containing a toner and a magnetic carrier; A developer regulating member that regulates the amount of developer transported and conveyed; a developer accommodating section that accommodates the developer scraped off by the developer regulating member; and a toner that is supplied toward the developer carrier. And a change in the toner concentration of the developer on the developer carrying member, thereby changing the contact state between the developer and the toner, thereby reducing the amount of toner taken in from the toner storage unit. In a developing device having a function of self-controlling and maintaining a toner concentration of the developer at a predetermined concentration, an end of the developer regulating member extends to a range where a tangential magnetic force of the fixed magnetic field generating means is generated. It is characterized by having made it.

In this developing device, the end of the developer regulating member extends within a range where the tangential magnetic force of the fixed magnetic field generating means is generated. As a result, the developer regulated by the developer regulating member obtains a conveying force by the tangential magnetic force, and is conveyed without being accumulated in front of the developer regulating member.

According to a third aspect of the present invention, in the developing device according to the first or second aspect, the developer contained in the developer accommodating portion is brought into close proximity to the developer carrier and scraped by the developer carrier. A magnetic member that rotates in a dropping direction is provided, and a peak position of a magnetic flux density distribution in a normal direction on a surface of the developer carrier is substantially opposed to the magnetic member.

By disposing the magnetic member,
As shown in FIG. 11, the tangential magnetic force of the fixed magnetic field generating means in the portion facing the magnetic member is further reduced. In this developing device, the end of the developer regulating member is
Since the fixed magnetic field generating means extends to a range where the tangential magnetic force of the fixed magnetic field generating means is reduced, avoiding the portion where the tangential magnetic force is reduced, the developer regulated by the developer regulating member is A transport force is obtained by the tangential magnetic force, and the developer is transported without being accumulated before the developer regulating member.

According to a fourth aspect of the present invention, in the developing device according to the first, second or third aspect, the extension position of the end of the developer regulating member is changed by a change in the magnetic flux density distribution in the normal direction of the fixed magnetic field generating means. It is characterized in that it is located near the pole position.

In this developing device, the extended position of the end of the developer regulating member is set near the inflection point of the magnetic flux density distribution in the normal direction of the fixed magnetic field generating means. Since it is near, the developer regulated by the developer regulating member is transported by the tangential magnetic force at which the transport magnetic force component has the maximum value. This allows the developer to be transported more smoothly without being accumulated before the developer regulating member.

According to a fifth aspect of the present invention, in the developing device of the first, second, third, or fourth aspect, the end of the developer regulating member is
The end portion and the surface of the developer carrying member may have a wedge-shaped inclined shape in which the downstream side in the developer transport direction is an acute angle.

In this developing device, the end of the developer regulating member is formed by the end and the surface of the developer carrier.
It is formed in an inclined shape having a wedge shape in which the downstream side in the developer transport direction is an acute angle. This prevents the developer carried and conveyed by the developer carrier from abruptly stalling when the developer comes into contact with the developer regulating member, and prevents a decrease in the developer conveyance force. become.

According to a sixth aspect of the present invention, there is provided an image carrier, a latent image forming means for forming a latent image on the image carrier, and a developing means for developing the latent image on the image carrier to form a toner image. 5. An image forming apparatus comprising: a transfer device for transferring a toner image on the image carrier onto a transfer material, wherein the developing device according to claim 1, 2, 3, or 4 is used as the developing device. Is what you do.

In this image forming apparatus, the developer carried and transported by the developer carrier is transported without being accumulated before the developer regulating member. The generation of white stripes on the toner image can be prevented, and a high-quality image can be obtained.

According to a seventh aspect of the present invention, in the image forming apparatus of the sixth aspect, when the latent image on the image carrier is developed, a developing portion between the image carrier and the developer carrier is provided. It is characterized in that an alternating electric field is applied.

In this image forming apparatus, when a latent image on the image carrier is developed, an alternating electric field is applied to a developing portion between the image carrier and the developer carrier. As a result, the fog toner is prevented from adhering to the background potential region of the toner image, and a high-quality image can be obtained.

According to an eighth aspect of the present invention, in the image forming apparatus of the sixth or seventh aspect, the developer for forming the toner image has a weight average diameter of 4 to 15 μm.

In this image forming apparatus, the resolution of the obtained image is improved because the weight average diameter of the developer is 4 to 15 μm.

According to a ninth aspect of the present invention, there is provided an image bearing member having a surface on which a latent image is formed, charging means for uniformly charging the surface of the image bearing member, and developing means for developing the latent image. At least one of cleaning means for cleaning the surface of the image carrier is a process cartridge integrally supported and detachably attached to the image forming apparatus main body, According to another aspect of the present invention, the developing device includes the developing device according to any one of claims 1, 2, 3, and 4.

In this process cartridge, the developer carried by the developer carrying member of the developing means is carried without being accumulated in front of the developer regulating member. It is possible to prevent the generation of white streaks on the toner image as a cause, and to provide a process cartridge capable of obtaining a high quality image.

[0040]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment in which the present invention is applied to a developing device used in an electrophotographic copying machine as an image forming apparatus will be described below. FIG. 1 shows a schematic configuration of the developing device 100. Here, among the constituent members of the developing device 100, members having the same configuration or the same function as the respective constituent members of the developing device illustrated in FIGS. 6 and 7 are denoted by reference numerals of the respective constituent members of the developing device. The description thereof is omitted.

In the developing device 100 of this type, when the developer accumulating portion A of the developer 3 is formed on the front side of the first doctor 6 as described above, the developer accumulating portion A is accumulated in the developer accumulating portion A. The developer is agglomerated and solidified by the influence of the temperature and the like, and the gap between the first doctor 6 and the developing sleeve 4 is closed, so that the flow of the developer 3 contained in the developer containing section 7 is obstructed. As a result, the toner image formed on the photosensitive drum 1 may have a white stripe.

Accordingly, the developing device 100 according to the present embodiment
In FIG. 1, the end 6a of the first doctor 6 is disposed downstream of the vertical apex position of the developing sleeve 4 in the developer conveying direction, as shown in FIG. As a result, the developer 3 carried and transported by the developing sleeve 4 is transferred to the developer 3 before the first doctor 6.
The transport force is obtained by the own weight of the first doctor 6 without being accumulated in front of the first doctor 6.

Further, in the developing device 100 according to the present embodiment, as shown in FIGS. 2 and 3, the end 6a of the first doctor 6 is connected to the tangential magnetic force P1 'of the magnet roller 5.
Is extended within the range of occurrence. As a result, the developer 3 regulated by the first doctor 6 obtains a conveying force by the tangential magnetic force P1 'of the magnet roller 5, and is conveyed without being accumulated before the first doctor 6. become.

Here, the extension position of the end 6a of the first doctor 6 is preferably near the inflection point of the magnetic flux density distribution in the normal direction of the magnet roller 5. That is,
By setting the extension position of the end 6 a of the first doctor 6 near the inflection point position of the magnetic flux density distribution in the normal direction of the magnet roller 5, the developer 3 regulated by the first doctor 6
Is transported by the tangential magnetic force at which the transport magnetic force component has the maximum value, and the accumulation in front of the first doctor 6 is further eliminated.

As shown in FIG. 1, the end 6a of the first doctor 6 has a wedge shape in which the end 6a and the surface of the developing sleeve 4 have an acute angle on the downstream side in the developer conveying direction. It is desirable that it is formed in an inclined shape. By forming the end 6a of the first doctor 6 in this way, the developer 3 carried and conveyed by the
When the abutment comes into contact with the one doctor 6, the stall does not suddenly stall, and a decrease in the conveying force of the developer 3 is prevented.

As described above, in the developing device 100 according to the present embodiment, the magnetic force arrangement around the developing sleeve 4 is as shown in FIGS. 2 and 3, and the developer before the first doctor 6 is disposed. The transport component of No. 3 becomes strong. The developer 3 pumped up by the stirring roller 9 is supplied to the first doctor 6
The developer 3 comes into contact with the first doctor 6 without stalling because the developer 3 comes into contact along the wedge-shaped end 6a.

FIG. 4 shows a schematic configuration of a process cartridge 200 provided with the developing device 100. In FIG. 4, in addition to the developing device 100, a charging unit 36, a cleaning unit 35, a waste toner storage case 31, and a cleaning unit 35 are provided around the photosensitive drum 1 serving as an image carrier.
A waste toner collecting roller 33 for feeding the waste toner 32 cleaned in the above to the waste toner accommodating case 31, a photosensitive drum 1, charging means 36, and a drum casing 34 holding the cleaning means 35 are provided.

The process cartridge 200 has the drum casing 34 configured as described above and the developing device 100 integrated with each other. The process cartridge 200 is roughly divided into a photosensitive unit 200A using the drum casing 34 as a support, a developing unit 200B using the developing casing 3 as a support, the toner hopper 13 from the left side in FIG. It is configured to be divided into three.

FIG. 5 shows a schematic configuration of an image forming apparatus 300 having a process cartridge 200 having the developing device 100. In the image forming apparatus 300, as shown in FIG. 5, the process cartridge 200 is detachably mounted to the image forming apparatus main body. In FIG. 5, the photosensitive drum 1 of the process cartridge 200
Is driven to rotate at a predetermined peripheral speed. The photosensitive drum 1 is uniformly charged with a predetermined positive or negative potential on its peripheral surface by the charging means 36 during the rotation process. Next, it receives image exposure light from the image exposure means 37 such as slit exposure or laser beam scanning exposure. Thus, an electrostatic latent image is sequentially formed on the peripheral surface of the photosensitive drum 1.

The electrostatic latent image formed on the photosensitive drum 1 is developed by developing means (developing device 100) of the process cartridge 200. As a result, the toner image formed on the surface of the photosensitive drum 1 is transferred between the photosensitive drum 1 and the transfer means 39.
Synchronously with the rotation of, the image is sequentially transferred to the transfer material fed from the paper supply unit by the transfer unit 39. The transfer material to which the toner image has been transferred is separated from the surface of the photosensitive drum 1 and introduced into the fixing unit 40 to fix the image.
It is printed out of the apparatus as a copy (copy). The surface of the photosensitive drum 1 after the transfer of the toner image is
Cleaning means 3 for process cartridge 200
In step 5, the transfer residual toner is removed, the surface is cleaned, and after the charge is removed, the toner is repeatedly used for image formation.

The developing device 100 according to the present embodiment
In developing the electrostatic latent image formed on the photosensitive drum 1, a vibration bias voltage obtained by superimposing an AC voltage on a DC voltage is applied to the developing sleeve 4 by a power source (not shown) as a developing bias. . The background potential and the image potential of the electrostatic latent image formed on the photosensitive drum 1 are located between the maximum value and the minimum value of the vibration bias potential. As a result, an alternating electric field whose direction changes alternately is formed at the development site. In this alternating electric field, the toner and the carrier of the developer 3 vibrate violently, and the toner flies over the photosensitive drum 1 by shaking off the electrostatic restraining force on the developing sleeve 4 and the carrier, and forms a latent image on the photosensitive drum 1. Adhere accordingly.

The difference (peak-to-peak voltage) between the maximum value and the minimum value of the vibration bias voltage is preferably 0.5 to 5 KV, and the frequency is preferably 1 to 10 KHz. The waveform of the oscillation bias voltage may be a rectangular wave, a sine wave, a triangular wave, or the like. Further, the DC voltage component of the vibration bias is a value between the background portion potential and the image portion potential as described above, but the value closer to the background portion potential than the image portion potential is in the background portion potential region. This is preferable for preventing fogging toner from adhering to the surface. Here, when the waveform of the oscillation bias voltage is a rectangular wave,
It is desirable that the duty ratio be 50% or less. The duty ratio is the ratio of the time during which the toner goes to the photoconductor during one cycle of the vibration bias.

By doing so, the difference between the peak value of the toner going to the photoreceptor and the time average value of the bias can be increased, so that the movement of the toner is further activated and the toner becomes latent image. It can adhere to the potential distribution on the surface faithfully, and can improve roughness and resolution. Also, since the difference between the peak value of the carrier having the opposite polarity to the toner and the time average value of the bias toward the photoreceptor can be reduced, the movement of the carrier is calmed down, and the background portion of the latent image is reduced. The probability that the carrier adheres to the substrate can be greatly reduced.

The method for measuring the weight average diameter of the developer 3 is as follows.
Perform the following procedure. First, an aqueous electrolytic solution of 100 to 150
0.1 to 5 ml of a surfactant (preferably an alkylbenzene sulfonate) is added as a dispersant to each ml. Here, the electrolyte is about 1% N using primary sodium chloride.
aCl aqueous solution prepared, for example, ISOTON-
II (manufactured by Coulter) can be used. Here, 2 to 20 mg of the measurement sample is further added. The electrolytic solution in which the sample is suspended is subjected to a dispersion treatment for about 1 to 3 minutes with an ultrasonic disperser, and the volume and the number of the toner particles or the toner are measured by the measuring device using a 100 μm aperture as an aperture. Calculate volume distribution and number distribution. From the obtained distribution, the weight average particle diameter (D4) and the number average particle diameter of the toner can be obtained.

The channels are 2.00 to 2.52
less than 2.5 μm; less than 2.52 to 3.17 μm;
4. less than 4.00 μm; 4.00 to less than 5.04 μm;
04 to less than 6.35 μm; 6.35 to less than 8.00 μm; 8.00 to less than 10.08 μm; 10.08 to 1
2.70 μm or less; 12.70 to less than 16.00 μm;
16.00 to less than 20.20 μm; 20.20 to 25.
Less than 40 μm; 25.40 to less than 32.00 μm; 3
Thirteen channels of 2.00 to less than 40.30 μm are used, and particles having a particle size of 2.00 μm or more to less than 40.30 μm are targeted.

The ratio of the developer 3 to the entire toner is 75% to 93% for the binder resin and 3% to 1% for the colorant.
0%, release agent 3% ~ 8%, other components 1% ~ 7%
It is. Examples of the binder resin used include, for example, a homopolymer of styrene such as polystyrene, poly-p-chlorostyrene and polyvinyltoluene and a substituted product thereof; a styrene-p-chlorostyrene copolymer and a styrene-vinyltoluene copolymer. Coalesce, styrene-vinylnaphthalene copolymer,
Styrene-acrylic acid ester copolymer, styrene-methacrylic acid ester copolymer, styrene-α-chloromethyl methacrylate copolymer, styrene-acrylonitrile copolymer, styrene-vinyl methyl ether copolymer, styrene-vinylethyl Examples include ether copolymers and styrene-vinyl methyl ketone.

As the coloring agent, conventionally known inorganic or organic dyes / pigments can be used. For example, carbon black, aniline black, acetylene black, naphthol yellow, hansa yellow, rhodun lake, alizarin lake , Bengala, phthalocyanine blue, and induslen blue.

If necessary, a magnetic material can be used as a coloring agent. As the magnetic material, magnetite, γ-iron oxide, ferrite iron, iron oxide such as excess ferrite; magnetic metal such as iron, cobalt, nickel; iron oxide or magnetic metal, and cobalt, tin, titanium, copper,
A composite metal oxide alloy or a mixture with a metal such as lead, zinc, magnesium, manganese, aluminum, or silicon is used. These magnetic particles preferably have an average particle size in the range of 0.05 to 1.0 μm, more preferably in the range of 0.1 to 0.6 μm, and still more preferably 0.1 to 0.4 μm. It is better to be within the range.
These magnetic particles have a BET specific surface area measured by a nitrogen adsorption method of preferably 1 to 20 m 2 / g, particularly 2.5 to 2.5 m 2 / g.
The hardness is preferably in the range of 12 to 12 m @ 2 / g, and more preferably the Mohs hardness is in the range of 5 to 7. Examples of the shape of the magnetic particles include an octahedron, a hexahedron, a sphere, a needle, and a scale, and an octahedron, a hexahedron, and a sphere having little anisotropy are preferable.

When used as a magnetic toner, the magnetic toner particles containing a magnetic material preferably contain the magnetic material in an amount of 10 to 150 parts by weight, preferably 20 to 120 parts by weight, based on 100 parts by weight of the binder resin. In the toner used in the exemplary embodiment, a small amount of an additive can be used within a range that does not substantially adversely affect the toner. Examples of the additive include lubricant powders such as Teflon (registered trademark) powder, zinc stearate powder, and polyvinylidene fluoride powder; abrasives such as cerium oxide powder, silicon carbide powder, and strontium titanate powder; Fluidity-imparting agents or anti-caking agents such as aluminum oxide powder; conductivity-imparting agents such as carbon black powder, zinc oxide powder and tin oxide powder; and organic or inorganic fine particles of opposite polarity.

Further, a releasing agent can be added to improve the fixing property and the like. Examples of the release agent include paraffin wax and its derivatives, microcrystalline wax and its derivatives, Fischer-Tropsch wax and its derivatives, polyolefin wax and its derivatives, and carnauba wax and its derivatives. Derivatives include oxides, block copolymers with vinyl monomers, and graft-modified vinyl monomers. In addition, alcohols, fatty acids, acid amides, esters, ketones, hydrogenated castor oil and derivatives thereof, vegetable waxes, animal waxes, mineral waxes, and petrolactam can also be used.

As the charge controlling agent for controlling the toner to be negatively charged, for example, an organic metal complex and a chelate compound are effective, and a monoazo metal complex, an acetylacetone metal complex,
Examples thereof include an aromatic hydroxycarboxylic acid-based metal complex and an aromatic dicarboxylic acid-based metal complex. Other examples include aromatic hydroxycarboxylic acids, aromatic mono- and polycarboxylic acids and their metal salts, their anhydrides, their esters, and phenol derivatives such as bisphenol. Examples of the charge control agent for controlling the toner to have a positive charge include a modified product of nigrosine and a fatty acid metal salt; tributylbenzylammonium-1-hydroxy-4-naphthosulfonate;
Quaternary ammonium salts such as tetrabutylammonium tetrafluoroborate, and onium salts such as phosphonium salts, which are analogs thereof, and lake pigments thereof;
Triphenylmethane dyes and their lake pigments (as the lacking agent, phosphotungstic acid, phosphomolybdic acid,
Phosphotungsten molybdic acid, tannic acid, lauric acid, gallic acid, ferricyanide, ferrocyanide)
There is.

The number average particle size of the particulate charge control agent is preferably 4 μm or less, more preferably 3 μm or less. When these charge control agents are internally added to the toner particles, the toner particles are preferably 0.1 to 20 parts by mass, more preferably 0.2 to 10 parts by mass, based on 100 parts by mass of the binder resin. It is good to contain by mass. Further, the toner may be, if necessary, generally used additives for toner, for example, a fluidizing agent such as colloidal silica, a metal oxide such as titanium oxide and aluminum oxide, and a polishing agent such as silicon carbide. Agents, lubricants such as fatty acid metal salts, and the like. The inorganic fine powder is used in an amount of 0.
It is preferred to use from 1 to 2% by weight. If the amount is less than 0.1% by weight, the effect of improving toner aggregation is poor. If the amount is more than 2% by weight, problems such as toner scattering between fine lines, contamination inside the machine, scratches and abrasion of the photoreceptor tend to occur. is there.

As a method of mixing the additive with the toner,
A conventionally known method may be used, and mixing can be performed by a device such as a Henschel mixer or a speed kneader. The method for producing the toner powder after kneading and cooling the toner may be a conventionally known method. For example, after kneading and cooling, it is pulverized with a jet mill and classified. The electrostatic image developing toner can be used as a dry one-component developer and a dry two-component developer. When used as a two-component developer, the mixing ratio of the toner and the carrier is generally about 0.5 to 6.0 parts by weight of the toner per 100 parts by weight of the carrier. When used as a dry two-component developer, the amount of the carrier and the toner of the present invention is such that the toner particles adhere to the carrier surface of the carrier particles and have a surface area of 30 to 9%
It is preferable to mix both particles so as to occupy 0%.

As the core particles of the carrier constituting the developer 3, conventionally known particles may be used, for example, ferromagnetic metals such as iron, cobalt and nickel; alloys and compounds such as magnetite, hematite and ferrite; A composite of body fine particles and a resin is exemplified. It is preferable to coat the surface of these carriers with a resin for the purpose of increasing the durability. Examples of the resin forming the coating layer include polyolefin resins such as polyethylene, polypropylene, chlorinated polyethylene, and chlorosulfonated polyethylene; polystyrene, acrylic (eg, polymethyl methacrylate), polyacrylonitrile, polyvinyl acetate, polyvinyl alcohol, polyvinyl butyral; Polyvinyl and polyvinylidene resins such as polyvinyl chloride, polyvinyl carbazole, polyvinyl ether, and polybiliketone; vinyl chloride-vinyl acetate copolymers; silicone resins comprising organosiloxane bonds or modified products thereof (for example, alkyd resins, polyester resins, epoxy resins) Modified products such as resin and polyurethane); polytetrafluoroethylene, polyvinyl fluoride,
Fluorine resins such as polyvinylidene fluoride and polychlorotrifluoroethylene; polyamides; polyesters; polyurethanes; polycarbonates; amino resins such as urea-formaldehyde resins; and epoxy resins. Among these, silicone resins or modified products thereof, and fluorine resins, particularly silicone resins or modified products thereof are preferable in terms of preventing toner spent. As a method of forming the coating layer, a coating layer forming liquid may be applied to the surface of the carrier core particles by a method such as a spraying method and an immersion method, as in the related art. The thickness of the coating layer is preferably from 0.1 to 20 μm.

As the two-component developer, polyester resin (weight average particle diameter 300 μm, softening temperature 80.2 ° C.) 100 parts by weight Carbon black 10 parts by weight Polypropylene (weight average particle diameter 180 μm) 5 parts by weight quaternary ammonium salt 2 Parts by weight The mixture having the above composition was melt-kneaded, then pulverized and classified.

Further, 0.3 part by weight of hydrophobic silica was mixed with 100 parts by weight of the base colored particles, and the average particle size was 9.
0 μm toner was obtained. Further, 2 parts by weight of polyvinyl alcohol and 60 parts by weight of water were placed in a ball mill and mixed for 12 hours with respect to 100 parts by weight of magnetite prepared by a wet method to prepare a magnetite slurry. This slurry was spray-granulated with a spray drier to obtain spherical particles.

The particles were fired in a nitrogen atmosphere at a temperature of 1000 ° C. for 3 hours and then cooled to obtain core particles 1. Silicone resin solution 100 parts by weight Toluene 100 parts by weight 15 parts by weight of γ-aminopropyltrimethoxysilane 20 parts by weight of carbon black The above mixture was dispersed for 20 minutes with a homomixer to prepare coating layer forming liquid 1.

The coating liquid for forming a coating layer was coated on a surface of 1,000 parts by weight of core particles 1 using a fluidized bed type coating apparatus to obtain a silicone resin-coated carrier. 97.5 parts of the above magnetic carrier and 2.5 parts of toner
The two components were mixed at a ratio of the double portions to prepare a two-component developer.

[0069]

According to the first to fifth aspects of the present invention, the developer carried and conveyed by the developer carrying member obtains a conveying force by its own weight before the developer regulating member, thereby obtaining the conveying force. There is an excellent effect that the developer is conveyed without being accumulated before the developer regulating member.

In particular, according to the invention of claim 2, the developer regulated by the developer regulating member obtains a conveying force by the tangential magnetic force and is not accumulated before the developer regulating member. There is an excellent effect of being transported.

According to the third aspect of the present invention, the end of the developer regulating member avoids such a portion where the tangential magnetic force of the fixed magnetic field generating means is reduced, and the tangential magnetic force of the fixed magnetic field generating means is reduced. So that the developer regulated by the developer regulating member obtains a transport force by the tangential magnetic force and is transported without being accumulated in front of the developer regulating member. Has an excellent effect.

According to the fourth aspect of the present invention, the developer regulated by the developer regulating member is transported by the tangential magnetic force at which the transport magnetic force component has a maximum value. There is an excellent effect that the material is conveyed more smoothly without being accumulated in front of the agent regulating member.

According to the fifth aspect of the present invention, the end of the developer regulating member is formed between the end and the surface of the developer carrier.
Since the downstream side of the developer transport direction is formed in an inclined shape forming a wedge shape with an acute angle, when the developer carried and transported by the developer carrier comes into contact with the developer regulating member, There is an excellent effect that sudden stall is prevented and a decrease in the developer conveying force is prevented.

According to the sixth aspect of the present invention, the developer carried and conveyed by the developer carrier is conveyed without being accumulated before the developer regulating member. It is possible to prevent the generation of white stripes on the toner image, which is a cause of the problem, and to obtain an excellent effect that a high quality image can be obtained.

According to the seventh aspect of the present invention, it is possible to prevent the fog toner from adhering to the background potential area of the toner image, and to obtain an excellent effect of obtaining a high quality image. .

According to the invention of claim 8, since the weight average diameter of the developer is 4 to 15 μm, there is an excellent effect that the resolution of the obtained image is improved.

According to the ninth aspect of the present invention, the developer carried and carried by the developer carrying member of the developing means is carried without being accumulated before the developer regulating member. It is possible to prevent the generation of white stripes on the toner image due to the accumulation, and to provide a process cartridge capable of obtaining a high quality image.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram of a developing device according to an embodiment of the present invention.

FIG. 2 is a schematic sectional view showing a normal magnetic force of a magnet roller of the developing device.

FIG. 3 is a schematic sectional view showing a tangential magnetic force of a magnet roller of the developing device.

FIG. 4 is a schematic configuration diagram of a process cartridge provided with the developing device.

FIG. 5 is a schematic configuration diagram of an image forming apparatus equipped with the process cartridge.

FIG. 6 is a schematic configuration diagram showing a state before use of a conventional developing device.

FIG. 7 is a schematic configuration diagram showing a state when a conventional developing device is used.

FIG. 8 is a schematic sectional view showing a normal magnetic force of a magnet roller of the conventional developing device.

FIG. 9 is a schematic sectional view showing a tangential magnetic force of a magnet roller of the conventional developing device.

FIG. 10 is a schematic sectional view showing a normal magnetic force of a magnet roller of another conventional developing device.

FIG. 11 is a schematic sectional view showing a tangential magnetic force of a magnet roller of another conventional developing device.

[Explanation of symbols]

 Reference Signs List 1 photosensitive drum 2 developing casing 3 developer 4 developing sleeve 5 magnet roller 6 first doctor 6a end of first doctor 7 developer accommodating section 8 second doctor 9 stirring roller 10 developer inlet 11 toner supply path 12 toner DESCRIPTION OF SYMBOLS 13 Toner hopper 14 Agitator 15 Toner supply port 100 Developing device 200 Process cartridge 300 Image forming device A, B Developer stagnation part P1, P2, P3, P4 Normal magnetic force P1 ', P2', P3 ', P4' Tangent magnetic force

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification FI FI Theme Court ゛ (Reference) G03G 15/09 G03G 15/08 507E (72) Inventor Kiyonori Tsuda 1-3-6 Nakamagome, Ota-ku, Tokyo Ricoh Co., Ltd. (72) Inventor Koichi Kataoka 1-3-6 Nakamagome, Ota-ku, Tokyo Stock Company Ricoh (72) Masayuki Yamane 1-3-6 Nakamagome, Ota-ku, Tokyo Stock Company Inside Ricoh (72) Inventor Kenzen Sekine 1-3-6 Nakamagome, Ota-ku, Tokyo Inside Ricoh Company (72) Inventor Kentaro Matsumoto 1-3-6 Nakamagome, Ota-ku, Tokyo Inside Ricoh Company ( 72) Inventor Atsushi Daijiya 1-3-6 Nakamagome, Ota-ku, Tokyo F-term in Ricoh Co., Ltd. (reference) 2H005 AA00 EA05 2H031 AA01 AA03 AA12 AB03 AC19 AC20 AC30 AD03 AD11 BA03 BA08 BA09 BC00 CA11 2H077 AA06 AA12 AA14 AA20 AB03 AB06 AB13 AC04 AC12 AD06 AD13 AD16 AD36 BA08 BA09 CA03 DB02 EA03 EA13 EA16

Claims (9)

[Claims] 1. A developer carrying member having a fixed magnetic field generating means therein for carrying and transporting a two-component developer containing a toner and a magnetic carrier, and being carried and carried by the developer carrying member. A developer regulating member for regulating the amount of the developer, a developer accommodating portion for accommodating the developer scraped off by the developer regulating member, and a toner accommodating container for accommodating the toner to be supplied to the developer carrier Having a portion, by changing the toner concentration of the developer on the developer carrying member, changing the contact state between the developer and the toner, and self-controlling the amount of toner taken in from the toner storage portion, In a developing device having a function of maintaining a toner concentration of the developer at a predetermined concentration, the developer carrying member is constituted by a cylindrical body, and an end of the developer regulating member is provided at a vertical vertex of the developer carrying member. Position below the developer carrier in the developer transport direction A developing device, which is disposed on the upstream side. 2. A developer carrying member having a fixed magnetic field generating means therein for carrying and transporting a two-component developer containing a toner and a magnetic carrier, and being carried and carried by the developer carrying member. A developer regulating member for regulating the amount of the developer, a developer accommodating portion for accommodating the developer scraped off by the developer regulating member, and a toner accommodating container for accommodating the toner to be supplied to the developer carrier Having a portion, by changing the toner concentration of the developer on the developer carrying member, changing the contact state between the developer and the toner, and self-controlling the amount of toner taken in from the toner accommodating portion, In a developing device having a function of maintaining a toner concentration of the developer at a predetermined concentration, an end of the developer regulating member is extended to a range where a tangential magnetic force of the fixed magnetic field generating means is generated. Developing device. 3. The developing device according to claim 1, wherein the developer carrier is rotated in a direction in which the developer carried and conveyed by the developer carrier is scraped off. A developing device comprising a magnetic member, wherein a peak position of a magnetic flux density distribution in a normal direction on a surface of the developer carrier is opposed to the magnetic member. 4. The developing device according to claim 1, wherein the extended position of the end of the developer regulating member is near the inflection point of the magnetic flux density distribution in the normal direction of the fixed magnetic field generating means. A developing device, characterized in that: 5. The developing device according to claim 1, wherein an end of the developer regulating member is formed at an acute angle between the end and the surface of the developer carrying member in a direction downstream of the developer conveying direction. A developing device having an inclined shape having a wedge shape. 6. An image carrier, a latent image forming means for forming a latent image on the image carrier, a developing means for developing the latent image on the image carrier to form a toner image, and the image carrier 6. An image forming apparatus comprising: a transfer unit for transferring an upper toner image onto a transfer material; wherein the developing unit according to claim 1, 2, 3, 4, or 5 is used as the developing unit. apparatus. 7. An image forming apparatus according to claim 6, wherein, when developing the latent image on said image carrier, an alternating electric field is applied to a developing portion between said image carrier and said developer carrier. An image forming apparatus comprising: 8. The image forming apparatus according to claim 6, wherein a weight average diameter of the developer for forming the toner image is 4 to 1.
An image forming apparatus having a thickness of 5 μm. 9. An image carrier on which a latent image is formed on a surface, charging means for uniformly charging the surface of the image carrier, developing means for developing the latent image, and the image carrier At least one of cleaning means for cleaning the surface of the image forming apparatus is a process cartridge integrally supported and detachably mounted to the image forming apparatus main body; A process cartridge using the developing device according to claim 1, 2, 3, 4, or 5.