JP2002182463A - Developing device and image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a developing device and an image forming device capable of preventing toner from scattering due to insufficient stirring in replenishment and also avoiding abnormality of toner density by improving the mixing property of the toner mixed with developer. SOLUTION: The low toner concentration developer 4B, whose toner concentration becomes low because of toner consumption due to a toner image formed on a photoreceptor 1, is temporarily stored in a low toner concentration developer storage part 22 provided for the developing device 3 before being returned to the developer storage part 21 of the developing device 3, and then the storage part 22 is replenished with the toner. Thus, the toner during replenishment comes in contact with the developer 4B where the toner is consumed and the surface of carrier is exposed, so that the electrification for the toner starts stably and the toner scattering is prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image forming apparatus such as a copying machine, a facsimile, a printer, and the like, and a developing device of the image forming apparatus, and more particularly, to a developing unit for forming a toner image on an image carrier. A two-component developer in which a toner and a carrier are mixed is supplied from the developer accommodating section, and the developer accommodating so as to return the low-concentration developer whose toner has been consumed in the developing section to the developer accommodating section. The present invention relates to a developing device provided with a developer circulating / conveying unit for circulating and conveying a developer in a unit, and an image forming apparatus using the developing device.

[0002]

2. Description of the Related Art Conventionally, in an image forming apparatus such as a copying machine or a printer, an electrostatic latent image is formed on an image carrier such as a photosensitive drum or a photosensitive belt, and this electrostatic latent image is developed by a developing device. After the toner image is formed on the image carrier by developing with the developer supplied from the company, the toner image is transferred to a transfer material such as paper or an OHP sheet by a transfer unit to form an image.

As a developing device of this type of image forming apparatus,
One using a two-component developer in which a toner and a carrier are mixed is known. In an image forming apparatus using such a two-component developer, as is well known, only the toner in the two-component developer is consumed by the formation of the toner image. Therefore, in this type of image forming apparatus, in order to form a good image, it is indispensable to always keep the toner concentration of the developer contained in the developer containing section of the developing apparatus at an appropriate level. Therefore, in an image forming apparatus using such a two-component developer, for example, a toner concentration detecting device that detects the toner concentration of the developer is provided in the developing device, and the toner concentration detecting device responds to a change in the detection signal of the toner concentration detecting device. Thus, toner is supplied into the developer accommodating portion of the developing device.

In an image forming apparatus employing such a toner replenishing method, for example, in order to prevent the toner concentration from becoming too high due to excessive replenishment of the toner to the developer, the toner replenishment operation is performed intermittently. Further, an image forming apparatus in which the OFF time is longer than the ON time of the toner replenishing operation so that the developer and the replenished toner are sufficiently stirred during the time when the toner replenishing operation is OFF is provided. It is known (Japanese Utility Model Laid-Open No. 2-24859).

Further, as an image forming apparatus employing a control method different from the toner density control by the toner density detecting device, for example, the optical density of a reference image formed on an image carrier during an image forming operation is detected. It is known that an optical density detecting means is provided at a position facing an image carrier, and toner is supplied in accordance with a change in a detection signal of the optical density detecting means (for example, Japanese Patent Application Laid-Open No. 2-304471).
No.).

On the other hand, it has been found that in order to obtain a high-resolution and high-quality image by an electrophotographic method, it is necessary to develop a latent image as small as possible accurately and stably. Therefore, in this type of image forming apparatus, a method is used in which a small latent image is formed by making the exposure spot of a laser or the like smaller, and the particle size of the toner is made smaller in order to accurately develop this small latent image. Have been

As the toner used in the image formation, toner having a nearly spherical shape or toner having rounded corners of a pulverized toner (hereinafter simply referred to as “spherical toner”) is used.
It is known that the transfer rate is higher than that of the pulverized toner. Since spherical toner having such a high transfer rate reduces waste toner, its use is desired to promote energy saving, space saving, and miniaturization of the apparatus main body.

[0008]

In a developing device using a two-component developer, the developer is agitated in the developer accommodating portion to charge the toner in the developer. The sheet is transported to a developing section which is a section facing the carrier. For this reason, in this type of developing device, the toner particles are soared by the stirring and transport of the developer, forming a toner cloud, and the toner flows out of the developing device from a slight opening, for example, under the developing sleeve, and There is a problem that so-called "toner scattering" occurs. When such toner scattering occurs, the inside of the image forming apparatus is contaminated with toner, and if the degree is poor, the scattered toner adheres to the photoreceptor and the image may be stained.

In particular, it is known that the degree of toner scattering in a developing device using the above-described spherical toner is lower than that in a developing device using a conventional pulverized toner having a lower transfer efficiency. (JP-A-8-33912)
2). One of the reasons is that the spherical toner has much better fluidity than the pulverized toner, but the surface energy is reduced by the absence of unevenness of the surface, and the additive is responsible for improving the fluidity of the toner and giving charge. Is likely to be easily separated from the toner surface. In other words, when the additive is released from the toner, the rise of the charge at the time of frictional charging with the carrier is deteriorated, weakly charged or poorly charged toner is generated, and the toner having the insufficient charge amount leads to toner scattering.

Further, according to an experiment conducted by the present inventor, when a spherical toner produced by a polymerization method is used as a two-component developer, the toner is not degraded in an unused state, that is, the spherical toner is added. Even when the developer was coated, it was found that the developer in which the surface of the carrier was coated with the spherical toner had good fluidity, and was poor in mixing with the developer as compared with the pulverized toner. For this reason, the spherical toner supplied to the developer is slid and conveyed over the developer while forming the toner reservoir when the developer is agitated and conveyed. It turned out to be insufficient. As a result, when such a spherical toner is used, the toner may be scattered even when the toner is not scattered by the pulverized toner.

Also, for example, a reference image is formed on an image carrier, and the optical density of the reference image is detected by an optical density detecting means, and the ratio of the optical density to the optical density of the background portion of the image carrier is calculated. In an image forming apparatus configured to control the toner density based on this ratio, if the toner adheres excessively to the image carrier and the background stain occurs, the ratio cannot be obtained accurately, and the accurate toner There was a problem that the density could not be controlled. For this reason, in such an image forming apparatus, it is difficult to use a spherical toner that easily causes toner scattering.

Further, in a developing device provided with a toner density detecting device for detecting a toner density in a developing device and supplying toner in accordance with a change in a detection signal of the toner density detecting device, a spherical toner is used. When the toner is used as a replenishing toner, since the mixing property between the spherical toner and the developer is poor, a local toner density difference occurs in the developer in the developer accommodating portion, and normal toner density control is performed. The problem of not being able to do it occurred.

The present invention has been made in view of the above problems, and an object of the present invention is to improve the mixing property between a replenishing toner and a developer to prevent toner scattering due to insufficient stirring of the replenishing toner. Another object of the present invention is to provide a developing device and an image forming apparatus that can prevent occurrence of abnormality in toner density control.

[0014]

According to one aspect of the present invention, there is provided a developer accommodating section for accommodating a two-component developer in which a toner and a carrier are mixed, and a toner accommodating section on an image carrier. The developer is supplied from the developer accommodating section toward the developing section for forming an image, and the developer is returned to the developer accommodating section so that the low toner concentration developer consumed by the toner in the developing section is returned to the developer accommodating section. Developer circulating / conveying means for circulating / conveying the developer in the storage section, toner concentration detecting means for detecting the toner concentration of the developer, and toner for replenishing the developer based on the detection result of the toner concentration detecting means And a toner replenishing means for replenishing the low toner concentration developer. The low toner concentration developer accommodating portion for temporarily accommodating the low toner concentration developer before returning the developer to the developer accommodating portion is provided. The above toner supply to the density developer storage It is characterized in that it has configured to replenish the replenishing toner by stage.

In this developing device, the low toner concentration developer whose toner has been consumed in the developing section is temporarily stored in the low toner concentration developer storing section before returning to the developer storing section. You. Further, a toner for replenishment is supplied to the low-toner-concentration developer accommodating portion by the toner replenishing means. As a result, the replenishment toner is supplied to the low toner concentration developer in which the toner has been consumed, that is, the developer having a low toner coverage on the carrier surface. The contact probability is improved. As a result, the replenishing toner is efficiently attached to the low toner concentration developer, the mixing property between the replenishing toner and the developer is improved, and the charging rise of the replenishing toner is stabilized, The toner scattering of the supply toner is reduced. This also makes it possible to use a spherical toner having an average circularity of 0.95 or more as the replenishing toner. Here, the circularity refers to the circumference length of a circle having the same area as the projected area of the particle / the contour length of the projected image of the particle.

According to a second aspect of the present invention, in the developing device of the first aspect, there is provided a developer stirring means for stirring the developer contained in the low-toner-concentration developer containing section. It is.

In this developing device, the developer contained in the low-toner-concentration developer accommodating section is agitated by the developer agitating means. As the developer stirring means, for example, a stirring member such as a paddle can be used.
Thereby, the stirring efficiency between the low toner concentration developer in which the toner has been consumed and the toner for replenishment is improved.

According to a third aspect of the present invention, in the developing device according to the first or second aspect, the developer container for forming the developer accommodating portion and the developer container for forming the low toner concentration developer accommodating portion are provided. It is characterized by being formed of developer containers independent of each other.

In this developing device, the low-toner-concentration developer storage section and the developer storage section are separated from each other. This makes it possible to reliably separate the low-toner developer having a low toner concentration from the developer contributing to development, thereby reducing toner scattering during image formation.

According to a fourth aspect of the present invention, in the developing device of the first, second or third aspect, the toner density detecting means detects the toner density of the developer in the low toner density developer accommodating section, and detects the toner density. Toner replenishing means for controlling a replenishing amount of replenishing toner replenished by the toner replenishing means such that a mixing ratio of the toner and the carrier of the developer is maintained at a preset ratio based on a detection result of the means. It is characterized by having a quantity control means.

In this developing device, the replenishing toner supplied by the toner replenishing means is controlled by the toner replenishing amount control means such that the mixing ratio of the toner and the carrier of the developer is maintained at a predetermined ratio. Is controlled. Thus, when the replenishing toner is replenished,
The toner concentration of the low-toner developer in the low-toner developer container is maintained at a preset toner concentration.

According to a fifth aspect of the present invention, in the developing device of the first, second, third or fourth aspect, the toner concentration detecting means detects a magnetic permeability of the developer in the low toner concentration developer accommodating portion. Is used to detect the toner concentration of the developer.

In this developing device, the magnetic sensor detects the toner concentration of the developer. This allows
A small-sized and low-cost toner concentration detecting means can be obtained.

The invention of claim 6 is the invention of claims 1, 2, 3, 4
Or in the developing device of 5, the developer discharging means for discharging the developer in the low-toner-concentration developer accommodating section to the developer accommodating section, and the developer discharging means for discharging the developer in the low-toner-concentration developer accommodating section. The discharging to the developer accommodating portion is performed by controlling the operation of the developer discharging unit such that the toner concentration detected by the toner concentration detecting unit is equal to or higher than a preset toner concentration. It is characterized by having.

In this developing device, the discharge of the developer in the low-toner-concentration developer storage section to the developer storage section by the developer discharge section is detected by the toner-concentration detection section. The operation of the developer discharging unit is controlled so that the operation is performed when the measured toner concentration is equal to or higher than a preset toner concentration. As a result, the developer in the low-toner-concentration developer accommodating section can be discharged in a timely manner,
The replenishment toner does not spill out of the low toner concentration developer storage section.

The invention of claim 7 is the invention of claims 1, 2, 3, 4
Or the developer discharging means for discharging the developer in the low-toner-concentration developer accommodating section to the developer accommodating section, and a developer for detecting the amount of the developer in the low-toner-concentration developer accommodating section. An amount detecting means, and a low toner concentration developer by the developer discharging means when the amount of the developer in the low toner concentration developer container detected by the developer amount detecting means reaches a predetermined amount of the developer. And a developer discharge control means for controlling the operation of the developer discharge means so as to start discharging the developer in the storage section to the developer storage section.

In this developing device, since the amount of the developer in the low-toner-concentration developer storage section does not increase too much, the stirring efficiency of the replenishment toner and the developer does not decrease.

The invention according to claim 8 is based on claims 1, 2, 3,
In the developing device of 4, 5, 6 or 7, the toner concentration detecting means detects the toner concentration of the developer in the low toner concentration developer accommodating section a plurality of times, and the detection result of the toner concentration detecting means is set in advance. A toner supply control unit that controls the toner supply unit so that the toner supply unit starts toner supply to the low toner concentration developer storage unit when the toner supply range converges to the toner concentration range. It is assumed that.

In this developing device, when the detection result of the toner concentration detecting means converges on a preset toner concentration range, toner supply to the low toner concentration developer accommodating section by the toner supplying means is started. . As a result, the next toner replenishment is performed after the toner pool that is not in contact with the carrier is eliminated, the replenished toner does not slip, the mixing efficiency is improved, and the toner surface and the carrier surface are easily contacted. Become.

According to a ninth aspect of the present invention, an electrostatic latent image formed on an image carrier is developed with a two-component developer in which a toner and a carrier are mixed to form a toner image on the image carrier. An image forming apparatus provided with the developing device according to claim 1, wherein the developing device is used as the developing device.
Wherein the developing device is used.

In this image forming apparatus, the developing device according to any one of claims 1, 2, 3, 4, 5, 6, 7, and 8 is used as the developing device. As a result, the developer supplied from the developing device is less likely to scatter the toner, and the surface of the image carrier is less likely to be contaminated by the adhesion of the scattered toner, so that the image quality of the toner image formed on the image carrier is less deteriorated. Become.

According to a tenth aspect of the present invention, in the image forming apparatus of the ninth aspect, transfer means for transferring the toner image formed on the image carrier by the developing device onto a transfer material, and Cleaning means for removing and collecting residual toner remaining on the image carrier after transferring the toner image,
And a collected toner conveying means for conveying the collected toner collected by the cleaning means to the low toner concentration developer accommodating portion of the developing device.

In this image forming apparatus, the collected toner conveyed by the cleaning means is conveyed to the low toner concentration developer accommodating section of the developing device by the collected toner conveying means. Thereby, the recovered toner used for image formation, such as the additive detached or buried from the toner surface, is replaced with the replenishment toner together with the low toner concentration developer stored in the low toner concentration developer storage section. It can be mixed and reused. Further, a hopper for stirring the unused replenishing toner and the collected toner in advance is not required, and the size of the apparatus main body can be reduced.

According to an eleventh aspect of the present invention, in the image forming apparatus of the tenth aspect, there is provided a heating element having a heating element, a film in contact with the heating element, and a pressurizing member for pressing the heating element through the film. A fixing device that heats and fixes the toner image on the transfer material by passing the transfer material onto which the toner image has been transferred by the transfer means between the film and the pressure member. It is characterized by doing.

In this image forming apparatus, the transfer material on which the toner image has been transferred by the transfer means passes between the film of the fixing device and the pressing member, so that the toner image is heated on the transfer material. Be established. The fixing device having such a configuration has a high fixing efficiency and can shorten a rise time until the fixing device is brought into a fixable state.

According to a twelfth aspect of the present invention, in the image forming apparatus of the ninth, tenth or eleventh aspect, a toner having a weight average diameter of 4 to 15 μm is used as the toner of the developer. .

In this image forming apparatus, a toner having a weight average diameter of 4 to 15 μm is used as the toner of the developer. Here, when a toner having a weight average diameter smaller than 4 μm is used, the toner scatters violently, and the image quality is deteriorated due to background contamination. Further, when a toner having a weight average diameter larger than 15 μmm is used, the particle diameter of the toner becomes extremely larger than the dots of the latent image,
The resolution of the resulting image is reduced.

The thirteenth aspect of the present invention relates to the ninth, tenth, and first aspects.
The image forming apparatus according to 1 or 12, further comprising an alternating electric field forming means for forming an alternating electric field in the developing section when the developing device develops the electrostatic latent image on the image carrier. Is what you do.

In this image forming apparatus, when the electrostatic latent image on the image carrier is developed by the developing device, for example, an oscillating bias voltage obtained by superimposing an AC voltage on a DC voltage is applied to the developing unit. , An alternating electric field is formed. Thereby, the toner in the developer supplied from the developing device is
The toner adheres to the electrostatic latent image on the image carrier while vibrating in the developing unit. As a result, the toner does not clump and adhere to the electrostatic latent image, and a high-definition image without roughness can be obtained.

The invention of claim 14 is the invention of claims 9, 10, 1
The image forming apparatus according to 1, 12, or 13, further comprising a charging device that charges a surface of the image carrier by bringing a charging member into contact with the image carrier and applying a voltage to the charging member. It is characterized by the following.

In this image forming apparatus, the surface of the image carrier is charged by contact charging. As described above, since the surface of the image carrier is charged by contact charging, generation of ozone due to the charging is reduced.

[0042]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment in which the present invention is applied to an image forming apparatus such as a copying machine, a facsimile, a printer and the like will be described below. The photoconductor 1 as an image carrier of the image forming apparatus is rotated in a direction indicated by an arrow (counterclockwise) in FIG. Thereafter, image exposure is performed by exposing a document image from an exposure unit (not shown) or optical writing with laser light from an optical writing device (not shown), and an electrostatic latent image is formed on the photoconductor 1.

A transfer belt 6 is provided downstream of the developing device 3 in the rotation direction of the photosensitive member 1.
Is stretched between a driving roller and a driven roller, and is turned in the direction of the arrow in the figure. Further, the transfer belt 6 is provided so as to be able to contact and separate from the photoconductor 1 by a contact and separation mechanism (not shown).
At the time of transfer, a nip portion is formed in contact with the photoconductor 1 and the transfer paper S is transported. A voltage (transfer output) having a polarity opposite to that of the toner is applied to the back surface of the transfer belt 6 via a bias roller 6a by a power supply (not shown).

Transfer paper S transported from a paper supply unit (not shown)
Is fed to the nip portion between the photosensitive member 1 and the transfer belt 6 by the registration roller 18 in synchronization with the image forming timing on the photosensitive member 1, and the toner image developed on the photosensitive member 1 The image is transferred onto the transfer paper S sandwiched between the photosensitive member 1 and the transfer belt 6 by the electric field between the members 1. The transfer paper S on which the toner image has been transferred is then conveyed by the transfer belt 6 and passes through a fixing device (not shown).
The toner image is thermally fused on the transfer paper. Then, the transfer paper S after the fixing is discharged to a discharge unit (not shown). On the other hand, the toner remaining on the photoreceptor that has not been completely transferred is blocked by the cleaning blade 7 and put on the collecting coil 9 by the collecting spring 8. Then, the toner is returned to the developing device 3 by the collection coil 9 as recycled toner.
After the cleaning, the photosensitive member 1 is discharged by the discharge lamp 20.

The collection coil 9 is provided in a photoconductor and a cleaning unit (hereinafter referred to as PCU) 10. PCU10
A toner supply port 26 connected to the developing device 3 is opened at a front portion of the developing device 3, and the recycled toner is collected into the developing device 3 therefrom. New toner supplied from the toner bottle 19 is also supplied from the toner supply port 26.

In the developing device using the two-component developer as described above, the toner of the developer contained in the housing 130 is charged, and the charged toner is charged at a portion facing the photoconductor 109. It is transported to a certain developing section. For this reason, in this type of developing device,
The toner particles fly up due to the stirring and transport of the developer, forming a toner cloud. For example, the toner flows out of the developing device from a small opening such as under the developing sleeve 115, and so-called “toner scattering” occurs. Have a problem. In particular, in the developing device using the above-described spherical toner, the degree of toner scattering is worse than in the developing device using the conventional pulverized toner having a lower transfer efficiency.

Therefore, in this developing device, a developer whose toner density is reduced due to consumption of toner by forming a toner image on the photoreceptor (hereinafter, this developer is referred to as “low toner density developer”) ) Is temporarily stored in a low-toner-concentration developer container provided in the developing device before returning to the developer-container portion of the developing device 3, and replenishing toner is stored in the low-toner-concentration developer container. It is configured to replenish.

That is, in the developing device 3, as shown in FIG. 1, a first developer accommodating section 21 and a second developer accommodating section 22 are provided independently. In the initial state, the first developer accommodating section contains the developer 4A used for developing the latent image, and the second developer accommodating section is empty. As the developer 4A, a two-component developer which is a mixture of a magnetic powder and a non-magnetic toner called a carrier is used. When the developer 4A is stirred, the toner is charged by frictional charging.

A developing sleeve 5 having a plurality of magnets or a magnet roller having a plurality of magnetic poles therein is disposed at a position facing the photoconductor 1 of the developing device 3. The developer 4A is carried on the developing sleeve 5 by a magnetic force, is conveyed to a position facing the photoconductor 1, and develops the electrostatic latent image on the photoconductor 1 with toner. After the development, the developer (low-toner developer) 4 carried on the developing sleeve 5
B is a state in which the toner is consumed and the toner concentration is reduced by the development, and the carrier hardly carries the toner. This low toner concentration developer (hereinafter simply referred to as “developer 4B”) is a developing sleeve 5 in FIG.
The carrier is detached from the developing sleeve 5 at the tip of the magnet roller installed inside by the rotation of
Due to its own weight, the toner supply port 2 of the second developer container 22
Fall to 6.

FIG. 2 shows the movement of the developer 4B in the second developer container 22 by arrows. As shown in FIG. 3, the second developer accommodating portion 22 is formed by an inner case 23a and an outer case 23b. An opening 29 is provided at a position corresponding to the toner supply port 26 of the outer case 23b of the second developer container 22. Further, inside the second developer accommodating section 22, a second paddle 25 is provided as a stirring means for stirring the developer 4B. A spiral is cut around the outer periphery of the second paddle 25, and a second conveying screw 28 is provided inside the second paddle 25.
Are arranged. The replenishment toner is, as shown in FIG.
The toner is supplied into the second developer accommodating portion 22 from the near side of the toner supply port 26 as an inlet for the developer 4 </ b> B, and is stirred by the rotation of the second paddle 25.

Similarly, the carrier of the developer 4B enters the inside of the second paddle 25 through the toner supply port 26. In the developer 4B, the toner and the carrier are mixed by the rotation of the second paddle 25. Then, the developer 4B in which the toner and the carrier are mixed is supplied to the second paddle 25.
Is conveyed in the direction of arrow A by the conveying screw 28, and the second paddle 25 is discharged from the discharge port on the other end while being stirred.
(See FIG. 2). The developer 4B that has come out of the second paddle 25 is transported in the direction of arrow B by a spiral around the outer periphery of the second paddle 25.

FIG. 3 is a detailed sectional view of the inside of the second developer accommodating section 22. 4A illustrates an operation during mixing and stirring of the developer 4B and the replenishment toner, and FIG. 3B illustrates an operation when replenishing the developer 4B to the first developer accommodating portion 21 after the mixing and stirring. In the normal state, the state shown in FIG. 3A is maintained.

By the way, the second developer accommodating section 22 accommodates the developer 4B dropped from the developing sleeve 5 with the rotation of the developing sleeve 5, and supplies the developer 4B in accordance with the toner concentration of the developer 4B. Toner is supplied. Also,
In the inner case 23a of the second developer accommodating section 22,
A magnetic sensor 17 for detecting the toner density is provided, and the magnetic sensor 17 detects the toner density of the developer 4B. Here, when a highly fluid toner such as the spherical toner is used,
Since the toner hardly mixes with the carrier and the developer, the toner may come into contact with the magnetic sensor 17 alone, or the developer 4B having a low toner concentration may come into contact. Therefore, in such a case, as shown in FIG. 4, the output value of the magnetic sensor 17 is not stabilized within a short time.

That is, in such a developing device, the output value of the magnetic sensor 17 tends to be stable as the toner is well dispersed in the developer 4B. Therefore, in the developing device according to the present embodiment,
As shown in FIG. 5, the toner concentration of the developer 4B is detected a plurality of times by the magnetic sensor 17, and when the output value of the magnetic sensor 17 converges within a certain range, the developer 4B is sufficiently stirred. Judge that it was done. Then, when it is determined that the stirring of the developer 4B has been sufficiently performed,
As shown in FIG. 3B, the opening 29 of the inner case 23a corresponds to the opening 27 of the outer case 23b by a rotating mechanism (not shown) provided on the inner case 23a of the second developer accommodating portion 22. Until the inner case 23a rotates. As a result, the developer 4B falls naturally toward the first developer accommodating portion 21, and the developer 4A and the developer 4B are stirred and mixed by the first paddle 14 and used for development. After a predetermined time, the inner case 23a returns to the initial position shown in FIG. 3A by the rotation mechanism of the second developer accommodating portion 22.

The evaluation of toner scattering between the developing device according to the present embodiment and the conventional developing device was compared based on the amount of toner adhering to the background of the photosensitive member 1. The evaluation method is based on two levels of developer 50 having a toner concentration of 5% by weight and 7% by weight.
0 g is adjusted, the developer is stored in the developer storage section of each developing device, an A4 size chart with an image density of 7% is copied, and after 10 copies, 1.0 g of toner is supplied and immediately after replenishment. The time from the start and the background stain on the photoreceptor were transferred to a tape, and the ID was measured. As a result, as shown in the graph of FIG. 6, the developing device (Example 1) according to the present embodiment has a lower background dirt ID than the conventional developing device (Comparative Example).

In the above embodiment, the developing device in which the second developer accommodating portion 22 is a container independent of the first developer accommodating portion 21 has been described as an example. The first developer accommodating portion 2 depends on the positional relationship with the body 1.
1 and the developer 4 in the second developer container 22.
In the case where a configuration capable of easily separating the second developer container B from the second developer container 22 can be adopted, the second developer accommodating portion 22 may not be required to be an independent container.

In such a case, for example, as shown in FIG. 7, a developer separating wall 30 is provided between the first developer accommodating section 21 and the second developer accommodating section 22, and a normal state is provided. In this case, the configuration is such that the developer 4A and the developer 4B are not mixed. Further, a developer supply roller 31 is provided so as to be sandwiched between the developer separating wall 30 and the housing of the developing device. When the output value of the magnetic sensor 17 converges within a certain range, it is determined that the developer 4B has been sufficiently stirred, and the developer supply roller 31 is rotated by a developer supply roller rotating mechanism (not shown). Rotate. A spiral groove is cut on the surface of the developer supply roller 31. By the rotation of the developer supply roller 31, the developer 4 </ b> B pumped into the groove is supplied to the first developer storage unit 21. Then, the developer 4A and the developer 4B
Is stirred and mixed by the first paddle 14 and used for development. During this operation, the toner supply operation is not performed.

Here, when the output value of the magnetic sensor 17 in the second developer container 22 exceeds a predetermined value, the toner supply is stopped. As a result, an image forming step of forming a toner image on the photoconductor 1 is performed, and the carrier having a reduced toner concentration is supplied to the second developer accommodating portion 22 with the rotation of the developing sleeve 5. . As a result, as described above, while the toner supply is stopped, the toner concentration of the developer 4 </ b> B in the second developer accommodating portion 22 decreases with time. When the output value of the magnetic sensor 17 becomes equal to or less than the predetermined value, the toner supply is restarted.

It is desirable that the second developer accommodating section 22 is provided with a developer amount detecting means for detecting the amount of the developer 4B contained in the second developer accommodating section 22. For example, the inner case 23a of the second developer container 22
When the height h ′ is h ′ = h / 2 with respect to the height h, the piezoelectric sensor as the developer amount detecting means is attached. When the developer 4B comes into contact with the detection unit of the piezoelectric sensor, a detection signal is sent to a signal processing unit (not shown).
The detection interval of this detection signal may be about 0.1 to 0.5 sec. If the detection signal is continuously detected ten times, it is determined that the amount of the developer 4B has exceeded the maximum stirrable amount, and the inner case 23 of the second developer accommodating portion 22 is determined.
The rotation mechanism a rotates the inner case 23a to a position where the opening 29 of the inner case 23a corresponds to the opening 27 of the outer case 23b. Thereby, the developer 4B becomes
The developer naturally falls into the first developer accommodating portion 21 and is discharged therefrom. The developer 4A and the first paddle 14 are mixed by stirring and used for development. After a few seconds, the inner case 23a returns to the initial position shown in FIG. 7A by the rotation mechanism of the second developer accommodating section 22. The above h 'can be set by appropriately selecting a place where the stirring efficiency is good through experiments, such as a range of h / 2 ≦ h'<3h / 4.

In the developing device 3, the recycled toner collected by the collecting coil 9 is sent from the toner supply port 26 to the inside of the second paddle 25 in the second developer accommodating section 22 together with the supply toner. The recycled toner that has entered the inside of the second paddle 25 is mixed with the carrier, and is conveyed in the second paddle 25 as a developer in the direction of the arrow A by the second conveying screw 28, and while being stirred, the discharge port on the other end side From the inside of the second paddle 25. The developer that has come out of the second paddle 25 is transported in the direction of arrow B by a spiral around the outer periphery of the second paddle 25.

In this way, the recycled toner and the new toner are stirred with the carrier in the second developer accommodating section 22, and mixed with the developer 4A contributing to the development. The toner supply timing control based on the output value of the magnetic sensor 17 is also applied to the toner supply control of the recycled toner. In that case, the supply of the recycled toner is stopped by stopping the rotation of the collection coil 9.

The control unit of the image forming apparatus according to this embodiment includes an arithmetic processing unit (CPU) including a microcomputer (not shown), a storage device including RAM and ROM, a clock, a timer, and an input / output device (I / O). And an interface), an A / D conversion circuit, various control circuits, and the like. An operation unit (not shown) (including a display screen, various setting keys, ten keys, a start key, and the like) is connected to the control unit. Then, outputs from various sensors such as the toner density sensor 17 are input via an A / D conversion circuit or the like, and key input information from an operation unit is output.
Each part of the electrophotographic apparatus is controlled in accordance with detection information from various sensors, and the above-described image forming operation is controlled.

In this image forming apparatus, a contact-type charging device is used. As shown in FIG. 8, the photosensitive member 1 as an image carrier, which is a member to be charged, is driven to rotate at a predetermined speed (process speed) in the direction of an arrow. This photoconductor 1
The charging roller 2 which is a charging member brought into contact with the
And a conductive rubber layer 2b concentrically formed in a roller shape on the outer periphery of the metal core 2a. Both ends of the cored bar 2a are rotatably held by bearing members (not shown) or the like. The conductive rubber layer 2b of the charging roller 2
Is pressed against the photoreceptor 1 by a predetermined pressing force by a pressing means (not shown), and rotates following the rotation of the photoreceptor 1. Here, 1000 mm is placed on the core 2a having a diameter of 9 mm.
A medium resistance rubber layer of about 00 Ω · cm
The charging roller 2 on which a conductive rubber layer 2b having a thickness of 2 mm is formed is used. The core metal 2a of the charging roller 2 is electrically connected to a power supply 2c, and a predetermined bias is applied to the charging roller 2 by the power supply 2c. As a result, the surface of the photoconductor 1 is uniformly charged to a predetermined polarity and potential.

As the charging member, the charging roller 2
In addition, any form such as a magnetic brush and a fur brush may be used, and the form can be selected according to the specification and form of the image forming apparatus. Here, when using a magnetic brush, as a charging member, for example, various ferrite particles such as Zn-Cu ferrite are used, and a non-magnetic conductive sleeve for supporting the ferrite particles, a magnet roll included therein, and the like are used. Be composed. In the case of using a fur brush, for example, as a material of the fur brush, for example, carbon, copper sulfide, a metal, and a material subjected to a conductive treatment with a metal oxide are used, and this is used as a metal or another conductive treated core. A charging member is formed by winding or pasting on gold.

FIG. 9 shows an example in which the fur brush is used as a charging member. In FIG. 9, a brush roller 2 ′ made of a fur brush is applied to a photoreceptor 1 by a brush unit 2 ′ b.
Contact with a predetermined nip width with a predetermined pressing force against the elasticity of the contact. The brush roller 2 'as a contact charging member in the present example is composed of a metal core bar 2'a having a diameter of 6 mm also serving as an electrode, and a conductive rayon fiber REC-B manufactured by Unitika Ltd. as a brush on a pile. The obtained tape is wound in a spiral shape and has an outer diameter of 14 mm and a length of 250 mm.
mm roll brush. Brush part 2'b
Are 300 denier / 50 filaments and 155 brushes per square millimeter. The roll brush was inserted into a pipe having an inner diameter of 12 mm while being rotated in one direction, the brush and the pipe were set so as to be concentric, and the brush was left in a high-temperature and high-humidity atmosphere to bend with a habit. The resistance value of the brush roller 2 ′ is 10
It is 1 × 10 5 Ω at 0V. The resistance was calculated from the current flowing when a brush roller 2 ′ was brought into contact with a metal drum having a diameter of φ30 mm with a nip width of 3 mm and a voltage of 100 V was applied.

The resistance value of the charging member formed of the fur brush as described above is such that when a low withstand voltage defect such as a pinhole is formed on the photosensitive member 1 to be charged, excessive leakage occurs in this portion. In order to prevent an image defect in which a current flows into the charging nip portion and the charging nip becomes defective, a resistance of 104Ω or more is required.
Ω or less.

The brush may be made of REC-C or REC-M other than REC-B manufactured by Unitika.
1, REC-M10, and SA-7 manufactured by Toray Industries, Inc.
Sandaron manufactured by Nippon Silk Co., Ltd., Bertron manufactured by Kanebo Co., Ltd., Clacarbo manufactured by Kuraray Co., Ltd., a material in which carbon is dispersed in rayon, Robal manufactured by Mitsubishi Rayon Co., Ltd., and the like can be considered. One brush is 3 to 10 denier and 10
A density of １００100 filaments / bundle, 80-600 filaments / mm is preferred. The hair foot is preferably 1 to 10 mm.

The fur brush roller is rotationally driven at a predetermined peripheral speed (surface speed) in a direction (counter) opposite to the rotation direction of the photoconductor, and contacts the photoconductor surface with a speed difference. When a predetermined charging voltage is applied from a power source to the fur brush roller, the surface of the rotating photoconductor is uniformly contact-charged to a predetermined polarity and potential. In this embodiment, the contact charging of the photoreceptor by the fur brush roller is performed by direct injection charging, and the surface of the rotating photoreceptor is charged to a potential substantially equal to the charging voltage applied to the fur brush roller.

The charging member used in the present invention may take any form, such as a charging roller and a fur brush, in addition to the fur brush roller, and can be selected according to the specifications and forms of the electrophotographic apparatus. is there. When a charging roller is used, it is common to use a medium-resistance rubber layer of about 100,000 Ω · cm on a cored bar. When using a magnetic brush, the magnetic brush uses various ferrite particles such as Zn-Cu ferrite as a charging member, and is constituted by a non-magnetic conductive sleeve for supporting the charging member and a magnet roll included therein.

Further, in the charging device, a brush roller constituted by a magnetic brush as a charging member is brought into contact with a predetermined nip width with a predetermined pressing force against the elasticity of the brush portion.

As the magnetic brush as the contact charging member in this example, Zn-Cu ferrite particles having an average particle diameter of 25 μm and Zn-Cu ferrite particles having an average particle diameter of 10 μm were mixed at a weight ratio of 1: 0.05. Then, magnetic particles obtained by coating ferrite particles having an average particle size of 25 μm and having a peak at each average particle size position with a medium resistance resin layer were used. The contact charging member is constituted by the coated magnetic particles prepared above, and a non-magnetic conductive sleeve for supporting the coated magnetic particles, and a magnet roll included in the sleeve. 1mm
To form a charging nip having a width of about 5 mm between the photosensitive member and the photosensitive member. The gap between the magnetic particle holding sleeve and the photoconductor was about 500 μm. Furthermore, the magnet roll has a sleeve surface with respect to the peripheral speed of the photoreceptor surface.
It is rotated so that it rubs in the opposite direction at twice the speed,
The photoreceptor and the magnetic brush were uniformly contacted.

The shape of the charging member used in the present invention may be a magnetic roller, a charging roller, a fur brush, or the like.
It may take any form, and can be selected according to the specification and form of the electrophotographic apparatus. When a charging roller is used, it is common to use a medium-resistance rubber layer of about 100,000 Ω · cm on a cored bar. In the case of using a fur brush, for example, fur, which is conductively treated with carbon, copper sulfide, metal, and metal oxide, is used as the material of the fur brush, and is wrapped around a metal or other conductive metal core. It is used as a charging member by sticking or sticking. FIG. 10 is a graph showing a comparison between the applied voltage and the charging voltage of the contact charging mechanism and the discharge charging mechanism by the charging device.

The method for measuring the weight average diameter of the toner of the developer can be performed according to the following procedure. First, a surfactant (preferably an alkylbenzene sulfonate) is added as a dispersant in 100 to 150 ml of an aqueous electrolytic solution.
Add 1-5 ml. Here, the electrolytic solution is a solution prepared by using about 1% NaCl aqueous solution using primary sodium chloride.
For example, ISOTON-II (manufactured by Coulter) can be used.

Here, 2 to 20 mg of a measurement sample is further added. The electrolyte in which the sample was suspended was mixed with an ultrasonic
A minute dispersion process is performed, and the volume and number distribution of the toner particles or toner are measured by the measuring device using a 100 μm aperture as the aperture, and the volume distribution and the number distribution are calculated. From the obtained distributions, the weight average particle diameter of the toner (D4), can be determined and the number average particle diameter.

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 binder resin to the total toner is 7%.
5% to 93%, colorant 3% to 10%, release agent 3% to
8%, and other components are 1% to 7%. 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. Copolymer, styrene-vinyl naphthalene copolymer, styrene-acrylate copolymer, styrene-methacrylate copolymer, styrene-α-chloromethyl methacrylate copolymer, styrene-acrylonitrile copolymer, styrene-vinyl Examples include a methyl ether copolymer, a styrene-vinyl ethyl ether copolymer, 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, rhodum 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, iron oxides such as magnetite, γ-iron oxide, ferrite iron and excess ferrite;
Iron, cobalt, a magnetic metal such as nickel, and iron oxide or magnetic metal, cobalt, tin, titanium, copper, lead, zinc, magnesium, manganese, aluminum, composite metal oxide of metals such as silicon alloy or the mixture No.

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 0.6 μm. It is better to be within the range of 0.4 μm.
These magnetic particles have a BET specific surface area measured by a nitrogen adsorption method of preferably 1 to 20 m 2 / g, and particularly preferably 2.
The Mohs hardness is preferably in the range of 5 to 12 m2 / g, and more preferably 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.

Further, a small amount of an additive can be used in the above-mentioned toner within a range that does not substantially adversely affect the toner. Examples of the additive include Teflon (registered trademark) powder,
Lubricant powders such as zinc stearate powder and polyvinylidene fluoride powder; abrasives such as cerium oxide powder, silicon carbide powder and strontium titanate powder; fluidity imparting agents such as titanium oxide powder and aluminum oxide powder; For example, a conductivity imparting agent such as a carbon black powder, a zinc oxide powder, and a tin oxide powder; and organic fine particles or inorganic fine particles of opposite polarity can be used.

Further, a releasing agent may be added to the toner in order to improve the fixability 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 control agent for controlling the toner to be negatively charged, for example, organometallic complexes and chelate compounds are effective, and monoazo metal complexes, acetylacetone metal complexes, aromatic hydroxycarboxylic acid metal complexes, aromatic Dicarboxylic acid-based metal complexes. Others include aromatic hydroxycarboxylic acids, aromatic mono- and polycarboxylic acids and their metal salts, their anhydrides, their esters,
There are phenol derivatives such as bisphenol.

Examples of the charge controlling 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-
Quaternary ammonium salts such as naphthosulfonate and tetrabutylammonium tetrafluoroborate, and onium salts such as phosphonium salts which are analogs thereof, lake pigments thereof, triphenylmethane dyes and lake pigments thereof Examples include phosphotungstic acid, phosphomolybdic acid, phosphotungsten molybdic acid,
The tannic acid, lauric acid, gallic acid, ferricyanide, ferrocyanide), and the number average particle diameter 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
The content is preferably 0.1 to 20 parts by mass, more preferably 0.2 to 10 parts by mass with respect to 0 parts by mass.

If necessary, the above-mentioned toner may be used, if necessary, with additives for toner generally used, for example, a fluidizing agent such as colloidal silica, metal oxides such as titanium oxide and aluminum oxide, and silicon carbide. And a lubricant such as a fatty acid metal salt. The inorganic fine powder is preferably used in an amount of 0.1 to 2% by weight based on the toner. 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 for mixing the additives with the toner, a conventionally known method may be used, and the additives can be mixed with 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 by a jet mill and classified. 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 are mixed so that the particles occupy 30 to 90% of the surface area. Is preferred.

In the present invention, the core particles of the carrier constituting the developer may be those conventionally known, for example, ferromagnetic metals such as iron, cobalt and nickel; alloys and compounds such as magnetite, hematite and ferrite; A composite of a ferromagnetic fine particle and a resin is exemplified. The surface of the carrier is preferably coated with a resin for the purpose of further 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 of resin, polyurethane, etc.); polytetrafluoroethylene, polyvinyl fluoride, polyvinylidene fluoride, polychlorotrifluoro Fluorine resins such as styrene, polyamides, polyesters, polyurethanes, polycarbonates; - urea amino resins such as formaldehyde resins, epoxy resins and the like. 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,
As in the prior art, the coating layer forming liquid may be applied to the surface of the carrier core particles by means such as spraying and dipping. The thickness of the coating layer is preferably from 0.1 to 20 μm.

Hereinafter, a description will be given of an example of producing a toner in which the pulverized toner is made spherical. First, an apparatus for manufacturing the above-described spherical toner will be described. 11 and 12 show an outline of a spherical toner manufacturing apparatus. This spherical toner manufacturing apparatus has a rotating body 104 having a plurality of rotating blades 101 on an outer periphery, a lateral intake hole 102 on a side surface of a central portion, and an airflow outflow hole 103 on a peripheral portion for radially discharging an airflow.
And an air intake tube 105 connected to the intake horizontal hole 102 of the rotating body 104 for an airflow accompanied by the powder particles p, and the rotating body 1
And a housing 106 for preventing the powder particles p having been subjected to the shaping treatment from scattering outside the system, and a discharge pipe 108 provided in the housing 106 for an airflow accompanying the powder particles p having been subjected to the spheroidizing treatment. , A power source M for the rotating body 104. Further, each of the plurality of rotating blades 101 is a flat and long rigid body, and a root portion of each rotating blade 101 is fixed to a peripheral portion of the rotating body 104 via each airflow outflow hole 103, Each tip portion extends radially with a gap for forming a spheroidized path 107 of the powder particles accompanying the airflow flowing out of the respective airflow outflow holes 103, and the spheroidized path is a spheroidizing process of the powder particles p. A rotating device A having a longitudinal length sufficient for
Is configured to be sucked by the suction means B.

The spheroidizing path 107 for the powder particles in the rotating device A of the apparatus for producing spherical toner is formed so as to progress from the root to the tip end, so that the powder particles accompanying the air flow are At the time of rotation of 104, spherical path 1
07, the increase in the collision energy due to the rotational angular acceleration that increases as the traveling speed increases is offset by the decrease in the flow velocity that is inversely proportional to the increase in the cross-sectional area of the path. In addition, local heat generation can be avoided.

Therefore, in the rotating device A of the apparatus for producing spherical toner, the powder particles accompanying the airflow are subjected to spheroidizing processing while traveling along the spheroidizing path 107 of the powder particles. Thus, the housing 106 of the rotating device A is not used for spheroidizing the ejected resin powder particles by colliding the resin particles, but serves to seal the rotating device A system at the time of operation of the suction means B described later. And plays a major role in preventing the spheroidized powder particles from scattering out of the system. Further, the housing 106 can be provided with a water jacket for cooling on the outside thereof. Further, air cooling fins may be provided.

The air flow outflow holes 103 for radially flowing out the air flow in the rotating device A can be provided by piercing the pipe material of the pipe-shaped rotating shaft of the rotating body 4 or, for example, through a bearing. Alternatively, it may be provided by piercing a corresponding portion of the casing pipe for the rotating shaft which is extrapolated to the rotating shaft.

The rotating body 10 of the rotating device A
The rotating blade 1 in 4 is flat and the rotating body 10
Even if 4 is swirled by its power source M, only a small amount of the airflow accompanying the powder particles p is sucked into this device. Therefore, since only a small amount is discharged outside the apparatus system, the discharge pipe 108
By providing a suction means B, for example, a blower, an airflow accompanying the powder particles p to this system is sucked and discharged.

(Production Method 1) In a method for producing a spherical toner using such a spherical toner production apparatus, the flat and rectangular rotating blades 101 in the rotating device A are used.
The powder p obtained by pulverization (volume average particle diameter of 5 to 20 μm) is placed on a rotating body 104 provided with a plurality of
Guided by the swirling suction air volume of 4. Due to the turning force, the granular material p passes through the airflow outflow hole 103 in the periphery of the rotating body from the horizontal intake hole 102 in the center of the rotating body, and is radially (radial).
And repeatedly passes through the rotating blades 101 while repeatedly colliding. Then, the powder p is collected by the cyclone by the suction means B (for example, a blower) through the discharge pipe 108.

FIGS. 13 and 14 show another example of the apparatus for producing spherical toner. This spherical toner manufacturing apparatus supplies a plurality of rotary blades 111 on the outer periphery and an airflow accompanying the raw material powder particles p formed between the tips of the rotary blades 111 to the spherical path 117 of the powder particles. Air supply hole 113
And air guide holes 112a for guiding an air flow accompanying the spherically-treated powder particles p, which are radially arranged between the roots of the respective rotary blades 111, to the central exhaust lateral hole 112,
A rotating body 114 having
An exhaust pipe 115 for discharging an airflow accompanied by the spheroidized powder particles p, and a housing 116 for sucking and introducing the airflow surrounding the rotating body 114 and accompanying the raw material particles p into the system
And an air supply pipe 118 provided in the housing 116 for an air flow accompanied by the raw material powder particles p, and a power source M for the rotating body 114. Further, each of the plurality of rotating blades 111 is a rectangular flat or twisted rigid body, and the root portion of each rotating blade 111 transfers the powder particles p to the rotating body 114 through the respective air guide holes 112a. The rotary blades 111 are spirally fixed to the peripheral portion of the rotary body 114 with respect to the rotary shaft, and each rotary blade 111 rotates with a spiral structure that sucks an air current accompanying the powder particles p when the rotary body 114 turns. It is provided on the body 114. Further, each tip portion extends radially with a gap for forming a spheroidized path 117 of the powder particles accompanying the airflow flowing from each air supply port 113113, and the spheroidized path is formed by a spherical shape of the powder particles p. A rotating device C having a longitudinal length sufficient for the gasification treatment, and the exhaust pipe 115 of the rotating device C is provided with exhaust means D
It is configured to be sucked.

The spheroidizing path 117 for the powder particles in the rotating device C is widened in a spiral structure as it goes from the root to the tip direction. Therefore, when the rotating body 114 rotates, the powder particles accompanying the air flow are formed. However, the increase in the collision energy due to the rotational angular acceleration that increases as the vehicle travels along the spherical path 117 is offset by the decrease in the flow velocity that is inversely proportional to the increase in the path cross-sectional area. As a result, it is possible to avoid an extreme change in the flow rate in the spheroidizing path 117 and to avoid local heat generation.

Therefore, in the rotating device C of the spherical toner manufacturing apparatus, the powder particles accompanying the airflow are subjected to the spheroidizing process while traveling along the spheroidizing path 117 of the powder particles. The housing 116 in the rotating device C is not used for colliding the resin powder particles being blown into a spherical shape, but serves to seal the rotating device C system when the exhaust means D described below is operated, and to provide a spherical shape. It plays a role in preventing the powder particles after the chemical treatment from scattering outside the system.

In the rotating device C, an air guide hole 112a for guiding the airflow accompanying the spheroidized powder particles to the central exhaust horizontal hole 112 is formed in a pipe material of the rotary shaft of the rotary body 114. Alternatively, it may be provided by, for example, piercing a corresponding portion of a rotating shaft casing pipe externally inserted through a bearing.

Then, the rotating body 114 in the rotating device C
If the airflow accompanying the powder particles p is not effectively sucked and discharged into the spherical toner producing apparatus even if the airflow is rotated by the power source M, the exhaust means D provided in the exhaust pipe 115, for example, a blower By actuating, it is possible to effectively perform the suction and discharge of the airflow accompanying the powder particles p to the system.

(Production Method 2) In the production of a spherical toner using the above-mentioned spherical toner production apparatus, the powder particles pulverized and obtained by pulverizing a rotating body 114 provided with a plurality of rotating blades 111 spirally with respect to a rotating shaft. (Volume average particle size 5-20μ
m) is guided by the amount of swirling suction air of the rotating body 114, and the granular material p repeatedly passes through the rotating blades 111 from the outer periphery of the blade to the center of the shaft by the suction force. Then, the powder p is subjected to cyclone collection by an exhaust means D, for example, a blower through an exhaust pipe 115.

FIG. 15 shows an outline of an example of the multifunction device.
In this multifunction device, a plurality of unit rotation devices A shown in FIGS. 11 and 12 are used. Further, a plurality of unit rotation devices C shown in FIGS. 13 and 14 are used. Further, FIG.
The unit rotating device A shown in FIGS. 1 and 12 and the unit rotating device C shown in FIGS. 13 and 14 are used in combination. In this case, only one intake means B and / or one exhaust means D can be provided. The multifunction device is provided at its end with suction means B or exhaust means D, for example, a spherical toner collecting means via a blower, for example, a cyclone. Then, for example, the unit rotating device A can be arranged after the crusher j, the unit rotating device A can be arranged after that, and the unit rotating device A can be arranged after that. Further, the unit rotating device C can be arranged after the crusher j, the unit rotating device C can be arranged after that, and the unit rotating device C can be arranged after that. Further, the unit rotation device A can be arranged after the crusher j, the unit rotation device C can be arranged after that, and the unit rotation device A can be arranged after that. Conversely, the unit rotating device C can be arranged after the crusher j, the unit rotating device A can be arranged after that, and the unit rotating device C can be arranged after that.
Further, two unit rotation devices A are arranged after the crusher j,
Thereafter, the unit rotating device C can be arranged, or two unit rotating devices C can be arranged after the crusher j, and then the unit rotating device A can be arranged. Further, the number of these unit rotating devices can be four or more. Further, the number of the unit rotating devices may be only two.

(Production Method 3) In an example of a method for producing a spherical toner using the above-described composite device, a rotating device 109 having rotating blades 101 in a conduit 110 after a crusher j shown in FIG. A plurality of devices A or C are installed and pass through the rotating body 114. Then, the toner particles p
Through the suction means B, for example, a blower.

(Production Method 4) In another method for producing a spherical toner by the above-described composite device, a plurality of unit rotation devices C having rotating blades 111 are installed in an air supply pipe 118 after a pulverizer shown in FIG. Then, it passes through the rotating body 114. Then, the toner particles p are cyclone-collected by the blower through the exhaust pipe 115.

(Manufacturing Method 5) In the manufacturing method using the above-described spherical toner manufacturing apparatus, processing is performed at an atmospheric temperature in the pipe from the feeder outlet m to the center of the rotating body shown in FIG. When passing through the rotating part during spheroidization, it generates heat,
The higher the heat generation temperature is, the more easily the toner becomes spherical. However, the higher the ambient temperature in the apparatus is, the more easily the surface composition of the toner is changed and the more the melt is generated. Therefore, when the supply air temperature is 40
C or lower is desirable.

(Manufacturing Method 6) In the manufacturing method using the spherical toner manufacturing apparatus, the atmosphere temperature in the pipe from the feeder outlet n to the center of the rotating body shown in FIG. The reason is the same as the reason explained in the above-mentioned manufacturing method 5.

(Manufacturing method 7) In the manufacturing method using the spherical toner manufacturing apparatus, the rotary blade 1 shown in FIGS.
At a peripheral speed of 400 m / sec or less. The higher the peripheral speed of the rotating blade, the higher the speed, the more the impact force between the particles and the impactor is promoted, and the more spherical the surface.The higher the speed, the higher the heat generation at the time of impact, the more the surface composition of the toner changes, and the lower the charging ability. There is a concern that image quality will deteriorate.

(Manufacturing Method 8) In the manufacturing method using the spherical toner manufacturing apparatus, the rotary blade 1 shown in FIGS.
The processing is performed at a peripheral speed of 400 m / sec or less. The reason is the same as the reason described in the above-mentioned manufacturing method 7.

(Manufacturing Method 9) In the manufacturing method using the spherical toner manufacturing apparatus, the blower B shown in FIGS.
Is processed at 3 m3 / min (kg) or less. By this operation, the residence time of the particles colliding with the rotating blade 101 is lengthened, and spheroidization is promoted.

(Production Method 10) In the production method using the above spherical toner production apparatus, the blower D shown in FIGS.
Is processed at 3 m3 / min (kg) or less. Reason,
The reason is the same as that described in the manufacturing method 9 above.

(Manufacturing Method 11) In the manufacturing method using the above-mentioned spherical toner manufacturing apparatus, the toner is treated so that the degree of aggregation of the toner before the sphering treatment is 70% or less. For spheroidization, individual particles need to be spheroidized. However, as the degree of toner aggregation increases, the particles are less likely to be loosened. The cohesiveness of the powder is
It is generally expressed by Carr's fluidity index and can be measured with a powder tester manufactured by Hosokawa Micron Corporation. If the degree of agglomeration in the fluidity index is 70% or less, the fluidity index tends to be spherical.

(Manufacturing Method 12) In the manufacturing method using the above-mentioned spherical toner manufacturing apparatus, processing is performed so that the degree of aggregation of the toner before the sphering processing is 70% or less. The reason is that the above manufacturing method 11
The reason is the same as described in the above.

(Manufacturing Method 13) In the manufacturing method using the spherical toner manufacturing apparatus, the toner and the additive are mixed before the sphering process. The fluidization index of the powder has an effect on the spheroidization of the toner. However, if the toner and the additive are mixed before the sphering treatment in order to improve the fluidization index, the toner tends to be spheroidized.

(Manufacturing Method 14) In the manufacturing method using the spherical toner manufacturing apparatus, the toner and the additive are mixed before the sphering process. The reason is the same as the reason described in the above-described manufacturing method 13.

Hereinafter, examples of the developer used in the developing device of the present embodiment will be described. However, the present invention is not limited to these examples. 100 parts by weight of styrene-acrylic copolymer, 10 parts by weight of carbon black, 5 parts by weight of polypropylene, 2 parts by weight of zinc salicylate, and a mixture having the above composition is melt-kneaded, cooled and pulverized to obtain a toner having an average particle diameter of 7.5 μm. Was. This was processed and classified and mixed by the manufacturing apparatus shown in FIGS. 11 and 12 and the manufacturing apparatus shown in FIGS. 13 and 14 under the conditions shown in Table 1 below. For the measurement of the shape, a relationship represented by sphericity = (surface area of sphere having the same volume as actual particles) / (surface area of actual particles) was adopted.

[Table 1]

(Production Example 1 as 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) A mixture of pentamer, quaternary ammonium salt, and 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.

The 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. 100 parts by weight of a silicone resin solution, 100 parts by weight of toluene, 15 parts by weight of γ-aminopropyltrimethoxysilane, 20 parts by weight of carbon black, and the above mixture were dispersed with a homomixer for 20 minutes to prepare a coating layer forming liquid 1.

This coating layer forming solution was coated on a surface of 1,000 parts by weight of the core particles 1 using a fluidized bed type coating apparatus to obtain a silicone resin-coated carrier. The magnetic carrier was mixed at a ratio of 5 parts by weight of the toner to 95 parts by weight to prepare a two-component developer.

Next, the polymerized toner will be described. (Toner Synthesis Example 1) A sealable reaction vessel equipped with a stirring blade, a cooling condenser, and a nitrogen gas inlet tube was installed in a thermostat, and the following composition was charged in the reaction vessel. 90 parts by weight of methanol and 2 parts by weight of a methyl vinyl ether / maleic anhydride copolymer.

After the methyl vinyl ether / maleic anhydride copolymer was completely dissolved by stirring, the one having the following composition was charged in a container. 30 parts by weight of styrene, 15 parts by weight of methyl acrylate, 1 part by weight of tert-dodecyl mercaptan, 1 part by weight of tert-butylacrylamide sulfonic acid.

When the air in the container was replaced with nitrogen gas, the temperature in the water tank was raised to 65 ° C., and the following was added. Azobisisobutyronitrile 0.4 part by weight / methanol 1 part by weight. Thereafter, the reaction was continued for 24 hours and then cooled to room temperature. Next, after charging the following dyes, the temperature was raised to 50 ° C., and the reaction was carried out for 5 hours. 1 part by weight of oil black 860, 0.2 parts by weight of oil orange 201.

The average particle size of the dyed particles in the dyeing solution is 6 μm.
(Standard deviation σ: 10%). Excess components in the dyeing solution were removed by centrifugation three times to obtain a dispersion A. In this dispersion A, 2 parts by weight of a core-shell type acrylic emulsion was added as a surface treatment agent to 100 parts by weight of the solid content, and the mixture was stirred at room temperature for 1 hour. Then, the mixture was sprayed onto a spray dryer GS31 (manufactured by Yamato Kagaku). Then, dry particles A were obtained. The dried particles A are subjected to an air pressure of 6 kg / cm 2 and a flow rate of 8
5m3 / h compressed air, air-flow type pulverizer: PJ
M-100NP was charged at a rate of 400 g / h. Next, the fine particles floating in the airflow were removed by a suction device. The composition change of the surface treatment agent of the obtained polymerized toner particles was measured by measuring the amount of fluorine atoms of the surface treatment agent by X-ray fluorescence. When the amount of fluorine atoms before the compressed air treatment is No and the amount of fluorine atoms after the compressed air treatment is N1, N1 / N
The value of 0 was 0.59. Next, 0.5 parts by weight of hydrophobic silica R976 (manufactured by Nippon Aerosil Co., Ltd.) was added to 100 parts by weight of the obtained polymerized toner particles, and mixed with a high-speed mixer to obtain a toner. The fluidity of the toner was evaluated by the angle of repose. The angle of repose refers to the angle formed by the generatrix of the cone and the horizontal plane when the powder fluid is gently dropped from a funnel or the like onto a flat surface and accumulates in a conical shape.
The angle of repose of the obtained toner was 26 degrees as measured with a powder tester manufactured by Hosokawa Micron Corporation, and the fluidity was also good.

(Toner Synthesis Example 2) Dry particles B were obtained in the same manner as in Synthesis Example 1 except that 2 parts by weight of the following fluorinated quaternary ammonium salt was added instead of the surface treating agent of Synthesis Example 1 described above. . The dried particles B were prepared in the same manner as in Synthesis Example 1,
The mixture was treated in a pulverizer, followed by high-speed mixing with hydrophobic silica. When the composition change of the surface treatment agent of the polymerized toner particles was measured in the same manner as in Toner Synthesis Example 1, the value of N1 / N0 was 0.84.

(Toner Synthesis Example 3) Dry particles C were obtained in the same manner as in Synthesis Example 1 except that zinc salicylate 2 parts by weight was added instead of the surface treating agent of Synthesis Example 1 described above. The dried particles C were treated in a gas stream pulverizer in the same manner as in Synthesis Example 1, and then mixed with hydrophobic silica at a high speed. When the composition change of the surface treatment agent of the polymerized toner particles was measured in the same manner as in Toner Synthesis Example 1, the value of N1 / N0 was 0.72.

(Toner Synthesis Example 4) A toner was prepared in the same manner as in Synthesis Example 1 except that the surface treatment agent was fixed by stirring at 50 ° C. for 1 hour while stirring at room temperature for 1 hour. When the composition change of the surface treatment agent of the polymerized toner particles was measured in the same manner as in Toner Synthesis Example 1, the value of N1 / N0 was 0.90.

(Toner Synthesis Example 5) A toner was prepared in the same manner as in Synthesis Example 1 except that the polymerized toner was not treated with an air-flow pulverizer.

(Toner Synthesis Example 6) A toner was prepared in the same manner as in Synthesis Example 3 except that the polymerized toner was not treated with an air-flow type pulverizer.

As a carrier to be used, a ferrite carrier (hereinafter referred to as carrier α) having an average particle size of about 50 μm and σs of 65 emu / g and coated with silicon (containing 10 wt% of aminosilane) was used.

On the other hand, in the developing device 3 shown in FIG.
At the time of development, an oscillating bias voltage in which an AC voltage is superimposed on a DC voltage is applied to the developing sleeve 5 as a developing bias by a power supply (not shown). The background portion potential and the image portion potential 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 in the developing unit. In this alternating electric field, the toner and carrier of the developer vibrate violently, and the toner is
In addition, it flies over the photoconductor drum 1 by shaking off the electrostatic restraining force on the carrier, and adheres to the latent image on the photoconductor drum.

Difference between maximum value and minimum value of vibration bias voltage
(Peak-to-peak voltage) is preferably 0.5 to 5 KV, and the frequency is preferably 1 to 10 KHz. As the waveform of the oscillation bias voltage, a rectangular wave, a sine wave, a triangular wave, or the like can be used. As described above, the DC voltage component of the vibration bias is a value between the background portion potential and the image portion potential. However, a value closer to the background portion potential than the image portion potential is more likely to cover the background portion potential region. It is preferable from the viewpoint of preventing toner from adhering.

When the waveform of the oscillation bias voltage is a rectangular wave,
It is desirable that the duty ratio be 50% or less. Here, the duty ratio is a ratio of a time during which the toner goes to the photoconductor in 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 potential of the toner on the latent image surface is increased. It adheres faithfully to the distribution and can improve roughness and resolution. Since the toner can be carriers of opposite polarity charge to reduce the difference between the time average value of the peak value and the bias to leaps to the photoconductor, the movement of the carrier subsided, the background portion of the latent image the possibility of the carrier to adhere can be greatly reduced.

The fixing device used in the image forming apparatus is, for example, a so-called surf fixing device for rotating and fixing a fixing film as shown in FIG. The fixing film 201 of the fixing device is an endless belt-like heat-resistant film, and is held by a driving roller 202 as a supporting rotating body of the film, a driven roller 203, and a heater supporting member provided between the two rollers. And the heating element 204 which is fixed and supported.

[0131] The driven roller 203
The fixing film 201 is also rotated in the clockwise direction by the rotation of the drive roller 201 in the clockwise direction in the drawing. The rotational drive speed is adjusted to a speed at which the speed of the transfer material and the speed of the fixing film become equal in the fixing nip region L where the pressure roller 205 and the fixing film 201 are in contact. Here, the pressure roller 205 is a roller having a rubber elastic layer having good releasability such as silicon rubber, and rotates counterclockwise while applying a total pressure of 4 to 10 kg to the fixing nip region L. The contact pressure is applied.

The fixing film 201 preferably has excellent heat resistance, releasability, and durability. A thin film having a total thickness of 100 μm or less, preferably 40 μm or less is used.
For example, a single-layer film of a heat-resistant resin such as polyimide, polyetherimide, PES (polyether sulfide), or PFA (tetrafluoroethylene verfluoroalkylvinyl ether copolymer resin) or a composite layer film, for example, at least an image of a 20 μm film. PTF on contact side
E (fluorotetraethylene resin), a fluororesin such as PFA, and the like, a release coating layer obtained by adding a conductive material to a thickness of 10 μm, or an elastic layer of fluororubber, silicon rubber, or the like.

In FIG. 17, the heating element 20 of the present embodiment is shown.
Reference numeral 4 denotes a flat substrate 206 and a fixing heater 207. The flat substrate 206 is made of a material having a high thermal conductivity and a high electrical resistivity such as alumina, and a fixing heater 207 formed of a resistance heating element is provided in a longitudinal direction on a surface in contact with the fixing film. Fixing heater 2
Reference numeral 07 denotes, for example, an electric resistance material such as Ag / Pd or Ta2N coated in a line or a band by screen printing or the like. Further, electrodes (not shown) are formed at both ends of the fixing heater 207, and when a current flows between the electrodes, the resistance heating element generates heat. Further, the fixing heater 20 of the substrate
A fixing temperature sensor 208 constituted by a thermistor is provided on a surface opposite to the surface provided in 7. The substrate temperature information detected by the fixing temperature sensor 208 is sent to a control unit (not shown), and the control unit controls the amount of electric power supplied to the fixing heater, and controls the heating element to a predetermined temperature.

[0134]

According to the first to eighth aspects of the present invention, the replenishing toner comes into contact with the developer in which the toner is consumed and the carrier surface is exposed, so that the rising of the charging of the toner is stabilized and the toner is scattered. There is an excellent effect that is prevented.

In particular, according to the second aspect of the present invention, since the developer contained in the low-toner-concentration developer containing section is agitated, an excellent effect that charging is sufficiently performed at the time of the next toner replenishment is achieved. is there.

Further, according to the third aspect of the present invention, it is possible to surely separate a low toner density developer having a low toner density from a developer contributing to development, thereby reducing toner scattering during image formation. Become. In other words, the low toner concentration developer and the developer contributing to development can be reliably separated, the toner can be efficiently stirred in the low toner concentration developer storage section, and the toner cloud generated at the time of stirring can be stored in the low toner concentration developer storage. Since the toner can be confined in the portion, there is an excellent effect that toner scattering does not occur.

According to the fourth aspect of the present invention, when the replenishing toner is replenished, the toner density of the low toner density developer in the low toner density developer accommodating section is changed to a preset toner density. Will be maintained. In other words, when the toner concentration exceeds the predetermined value, stopping the toner replenishment has an excellent effect that the carrier surface area where charging of the replenished toner at the next time is sufficiently performed can be maintained.

According to the invention of claim 5, there is an excellent effect that a small and low-cost toner density detecting means can be obtained.

According to the sixth aspect of the present invention, the developer in the low-toner-concentration developer accommodating section is discharged at appropriate times, and the replenishment toner does not spill out of the low-toner-concentration developer accommodating section. There is an excellent effect.

Further, according to the invention of claim 7, there is an excellent effect that the stirring efficiency does not decrease because the amount of the developer is not excessively increased.

Further, according to the invention of claim 8, the next toner replenishment is performed after the toner pool not in contact with the carrier is eliminated, so that the replenished toner does not slip and the mixing efficiency is improved. There is an excellent effect that the toner surface and the carrier surface are easily brought into contact with each other.

According to the ninth to fourteenth aspects of the present invention, the toner supplied from the developing device is less likely to scatter the toner, and the surface of the image carrier is less likely to be contaminated by the adhered scattered toner. There is an excellent effect that image quality deterioration of a formed toner image is reduced.

In particular, according to the tenth aspect of the present invention, deteriorated recovered toner used for image formation, such as an additive detached or buried from the toner surface, is stored in the low toner concentration developer storage section. The toner can be reused by mixing with the replenishment toner together with the low toner concentration developer. In addition, there is no need for a hopper for previously stirring the unused replenishing toner and the collected toner, and there is an excellent effect that the size of the apparatus main body can be reduced.

According to the eleventh to fourteenth aspects of the present invention, there is an excellent effect that the fixing efficiency is good and the rise time until the fixing state becomes possible can be shortened.

According to the twelfth aspect of the present invention, 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 thirteenth aspect of the present invention, the toner is prevented from adhering to the electrostatic latent image in the form of nodules, and a high-definition image free from roughness can be obtained. effective.

According to the fourteenth aspect of the present invention, the surface of the image carrier is charged by contact charging, so that there is an excellent effect that generation of ozone due to the charging is reduced.

[Brief description of the drawings]

FIG. 1 is a configuration of a low-toner-concentration developer accommodating section, a toner-concentration detecting unit, a low-toner-concentration developer conveying mechanism, and a stirring mechanism in a low-toner-concentration developer accommodating section of a developing device in an image forming apparatus according to an embodiment of the present invention. FIG.

FIG. 2 is a schematic perspective view showing a configuration of a second developer accommodating portion inside the developing device shown in FIG. 2 and movement of the developer.

3A is a cross-sectional view illustrating a state in a mixing and stirring mode of a second developer accommodating portion inside the developing device illustrated in FIG. 2; (B)
FIG. 4 is a cross-sectional view illustrating a state of the second developer storage unit in a developer discharge mode.

FIG. 4 is a transition diagram showing a transition of an output of a toner density sensor of the developing device.

FIG. 5 is a flowchart illustrating a toner supply control operation of the developing device.

FIG. 6 is a graph comparing the amount of toner scattering between the developing device according to the embodiment and a comparative example.

FIG. 7 is a schematic view showing an example in which the second developer accommodating section is not constituted by an independent container.

FIG. 8 is a schematic diagram showing a charging device in the image forming apparatus.

FIG. 9 is a schematic diagram illustrating another charging device in the image forming apparatus.

FIG. 10 is a graph showing a comparison between the applied voltage and the charging voltage of a contact charging mechanism and a discharge charging mechanism by the charging device.

FIG. 11 is a view for explaining an example of an apparatus for producing a spherical toner.

FIG. 12 is a schematic diagram illustrating a schematic configuration of a manufacturing apparatus of the spherical toner.

FIG. 13 is a view for explaining another example of the apparatus for manufacturing a spherical toner.

FIG. 14 is a schematic diagram illustrating another schematic configuration of the spherical toner manufacturing apparatus.

FIG. 15 is a view for explaining one example of a composite production apparatus for spherical toner according to the present embodiment.

FIG. 16 is a view for explaining an example of a conventional toner manufacturing apparatus.

FIG. 17 is a schematic diagram illustrating a fixing device used in the image forming apparatus according to the embodiment of the invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Photoconductor 2 Charging roller 3 Developing device 4A Developer 4B Low toner concentration developer 6 Transfer belt 6a Bias roller 8 Collection spring 9 Collection coil 10 Cleaning unit 17 Magnetic sensor 18 Registration roller 19 Toner bottle 20 Static removal lamp 21 First developer Container 22 Second developer container 23a Inner case 23b Outer case 25 Second paddle 26 Toner supply port 27, 29 Opening 28 Second transport screw 30 Developer separating wall 201 Fixing film S Transfer paper

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) G03G 21/10 G03G 15/08 507D 507L 21/00 326 F term (Reference) 2H027 DA38 DA41 DD03 DD07 DE04 DE07 DE09 EA06 EC06 EC09 EC15 EC20 ED03 ED10 ED24 ED25 ED27 EE04 2H034 AA06 CA01 CA04 CB01 2H077 AA03 AA05 AA12 AA34 AA35 AA37 AB03 AB07 AB14 AC03 AC16 AD06 AD36 DA10 DA52 DB02 EA01

Claims (14)

[Claims] 1. A developer accommodating portion for accommodating a two-component developer in which a toner and a carrier are mixed, and a developer accommodating portion for forming a toner image on an image carrier from the developer accommodating portion. A developer circulating / conveying means for circulating / conveying the developer in the developer accommodating section so as to return the low-concentration developer in which the toner has been consumed in the developing section to the developer accommodating section; A toner density detecting means for detecting the toner density of the toner, and a toner replenishing means for replenishing toner for replenishment in the developer based on the detection result of the toner density detecting means. A developer is provided with a low-toner-concentration developer accommodating section that temporarily accommodates the developer before returning to the developer accommodating section,
A developing device characterized in that the low toner concentration developer accommodating section is configured to replenish toner for replenishment by the toner replenishing means. 2. The developing device according to claim 1, further comprising a developer stirring means for stirring the developer contained in said low toner concentration developer containing section. 3. The developing device according to claim 1, wherein the developer container forming the developer storage portion and the developer container forming the low toner concentration developer storage portion are separated from each other. A developing device formed of a container. 4. A developing device according to claim 1, wherein said toner concentration detecting means detects a toner concentration of a developer in said low toner concentration developer accommodating section, and the detection result of said toner concentration detecting means is provided. A toner replenishing amount control unit for controlling a replenishing amount of the replenishing toner replenished by the toner replenishing unit such that a mixing ratio of the toner and the carrier of the developer is maintained at a preset ratio. A developing device. 5. A developing device according to claim 1, wherein said toner concentration detecting means detects the toner of the developer by a magnetic sensor which detects a magnetic permeability of the developer in the low toner concentration developer accommodating portion. A developing device for detecting a density. 6. A developing device according to claim 1, 2, 3, 4, or 5, wherein said developer in said low-toner-concentration developer container is discharged to said developer container. The discharging of the developer in the low-toner-concentration developer accommodating section to the developer accommodating section by the discharging means is performed such that the toner concentration is detected when the toner concentration detected by the toner concentration detecting means is equal to or higher than a preset toner concentration. A developer discharge control unit for controlling the operation of the discharge unit. 7. The developing device according to claim 1, wherein the developer in the low-toner-concentration developer container is discharged to the developer container. A developer amount detecting means for detecting the amount of the developer in the concentration developer accommodating section, and the amount of the developer in the low toner concentration developer accommodating section detected by the developer amount detecting means has reached a preset developer amount. A developer discharge control means for controlling an operation of the developer discharge means so as to start discharge of the developer in the low toner concentration developer storage part to the developer storage part by the developer discharge means. A developing device. 8. The developing device according to claim 1, wherein the toner concentration detecting means detects the toner concentration of the developer in the low toner concentration developer accommodating section a plurality of times. When the detection result of the toner density detecting means converges on a preset toner density range, the toner replenishing means controls the toner replenishing means so as to start replenishing the toner to the low toner concentration developer accommodating part. A developing device having a toner replenishment control unit for performing the operation. 9. A developing device for developing an electrostatic latent image formed on an image carrier with a two-component developer in which a toner and a carrier are mixed to form a toner image on the image carrier. The image forming apparatus according to claim 1, wherein the developing device is a developing device.
An image forming apparatus using the developing device of 7 or 8. 10. An image forming apparatus according to claim 9, wherein said developing device transfers said toner image formed on said image carrier to a transfer material, and said toner image is transferred onto said transfer material. A cleaning unit that removes and collects residual toner remaining on the image carrier later, and a collected toner conveying unit that conveys the collected toner collected by the cleaning unit to the low toner concentration developer accommodating portion of the developing device. An image forming apparatus comprising: 11. An image forming apparatus according to claim 10, further comprising: a heating element having a heating element, a film in contact with said heating element, and a pressing member in pressure contact with said heating element via said film. And a fixing device that heats and fixes the toner image on the transfer material by passing the transfer material onto which the toner image has been transferred by the transfer means between the film and the pressing member. Characteristic image forming apparatus. 12. The image forming apparatus according to claim 9, 10 or 11, wherein the toner of the developer has a weight average diameter of 4 to 15 μm.
An image forming apparatus characterized by using the above toner. 13. An image forming apparatus according to claim 9, 10, 11 or 12, wherein an alternating electric field is formed in said developing section when said developing device develops an electrostatic latent image on said image carrier. An image forming apparatus comprising a forming unit. 14. An image forming apparatus according to claim 9, 10, 11, 12, or 13, wherein a charging member is brought into contact with said image carrier, and a voltage is applied to said charging member so that the surface of said image carrier is formed. An image forming apparatus, comprising: a charging device that charges the toner.