JP3461450B2 - Image forming apparatus and image forming method - Google Patents

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 and an image forming method for reusing a developer, which is applied to a printer, a facsimile machine, a copying machine or the like which employs an electrophotographic system or an electrostatic recording system.

[0002]

2. Description of the Related Art In an electrophotographic image forming apparatus, an electrostatic latent image is formed on a photosensitive drum, which is an image carrier, and the electrostatic latent image is developed using toner supplied from a developing device. The toner is transferred onto a transfer material such as paper or an OHP (overhead projector) sheet, and is fixed by heating or pressing to form an image.

In such an image forming process, most of the toner adhering to the electrostatic latent image on the photosensitive drum is transferred to the transfer material and consumed.
20% by weight of toner remains on the photosensitive drum. The amount of toner remaining on the photosensitive drum is easily affected by environmental conditions. For example, in a high temperature and high humidity environment, the transfer efficiency decreases, so that a larger amount of toner remains.

Although the residual toner has been collected and discarded by the cleaning means, a mechanism for reusing the collected toner has been proposed in consideration of effective use of resources. For example, the collected toner is returned to the developing device by a mechanical conveying means such as a screw. By reusing the collected toner, the number of images formed can be increased and the labor for discarding the toner can be saved.

On the other hand, it is known that a small amount of toner is crushed by being subjected to stress due to mechanical agitation with a carrier in the developing device, but when returning the recovered toner to the developing device as described above. Even the toner is crushed. Therefore, the amount of fine powder of toner in the developing device remarkably increases,
The average particle size and particle size distribution may change significantly. Further, since the molecular chain of the resin is broken by the pulverization, the molecular weight distribution of the resin in the toner is changed and the fixing property is deteriorated. Further, the developer contains additives such as an external additive and a fluidizing agent in a predetermined ratio in addition to the toner and the carrier, but the toner is selectively transferred at the time of transfer, so the toner is added by reusing the toner. The ratio of the agent changes. Therefore, the image formation is adversely affected. For example, the density of the reflected image is reduced, or fog occurs.

Further, it has been proposed to use a toner made of a resin which is difficult to be crushed when the collected toner is reused. By using the toner, the crushing efficiency in the crushing step in the toner manufacturing is lowered, The cost increases. It has also been proposed to add an additive in the initial stage. This increases the fluidity of the toner, but since the collected toner is supplied to the developing device earlier than the set time from when the toner is supplied to the developing device until the collected toner is supplied to the developing device, the toner May be scattered from the developing device.

As described above, the reuse of the recovered toner has various problems such as a decrease in the density of the reflected image, the occurrence of background fog and reverse fog, and the occurrence of toner scattering. Further, as one of the causes of these problems, the influence of the paper powder contained in the recovered toner is considered. In order to remove the paper dust, a filter may be provided on the recovery toner conveying path, but this complicates the apparatus configuration and causes a problem that the paper dust accumulates on the filter and the collected toner is clogged. Japanese Unexamined Patent Publication No. 6-59501 proposes a toner configuration and an image forming apparatus in consideration of transportability and durability of collected toner.

[0008]

As described above, it is difficult to easily reuse the recovered toner, and the mechanism of the image forming apparatus, especially the mechanism of the developing device, the image forming method, especially the developing method, and Optimization of toner characteristics is desired.

An object of the present invention is to provide an image forming apparatus and an image forming method capable of stably forming an image of excellent image quality by reusing collected toner.

[0010]

SUMMARY OF THE INVENTION The present invention is directed to an image bearing member carrying a latent image, a developing unit for developing a latent image on the image bearing member by adhering a developer thereto, and a new developing unit provided to the developing unit. In an image forming apparatus including a replaceable container that stores the agent and a collector that collects the developer on the image carrier and supplies the developer to the developing device, the developer stored in each replaceable container The characteristic is that the image forming apparatus is characterized in that at least one of the average particle size, the particle size distribution, and the amount of fine powder is different from each other.

According to the present invention, the latent image on the image carrier is developed with the developer from the developing device. The developer is transferred and fixed on a transfer material, for example, to form an image. The developer contained in the container is supplied with the new developer, and the collector collects the developer collected from the image carrier. The characteristics of the recovered developer differ from the characteristics of the new developer due to stress at the time of recovery, but in the image forming apparatus of the present invention, the characteristics of the developer accommodated in each of the replaceable containers, that is, the average. At least one of the particle size, the particle size distribution, and the amount of fine powder has different developer characteristics.

For example, when the image is formed using the new developer in the first container, the developer is not reused, and the first developer is not reused.
When the new developer in the second container is exhausted and cannot be supplied to the developing device, recycling of the collected developer is started and the collected developer is supplied to the developing device. In the image forming apparatus that is secondly replaced,
The change in the developer characteristics caused by the reuse of the developer is controlled in consideration of at least one of the average particle diameter, the particle diameter distribution, and the amount of fine powder of the new developer in the second container. be able to. Therefore, an image with excellent image quality can be stably formed.

[0013]

[0014]

According to the present invention, the average particle size of the developer contained in the second container is 1.5 μm or more with respect to the average particle size of the developer contained in the first container. It is characterized in that it is large in the range of 2.0 μm or less.

According to the present invention, the differential amount increases in the recovered developer, but the average particle size is selected as described above as a characteristic of the developer of the second container which is exchangeable. In the mixed developer of the collected developer and the new developer from the second container, the average particle size can be controlled to an ideal value. Therefore, an image with excellent image quality can be stably formed.

Further, according to the present invention, 9.552 μm to 14.8 with respect to the total amount of the developer accommodated in the second container.
The proportion of the developer having a particle size in the range of 9 μm is 85%.
The above is characterized.

According to the present invention, the recovered developer causes a broadening of the particle size distribution, but as a characteristic of the developer in the second container which is replaceable, the particle size distribution is as described above. By selecting sharply, the collected developer and the second
In the mixed developer with the new developer from the second container,
The particle size distribution can be controlled to an ideal value. Therefore, an image with excellent image quality can be stably formed.

In the present invention, 2.02 μm to 4.91 μm based on the total amount of the developer contained in the second container.
The ratio of the amount of the developer having the fine particle diameter in the range of m is 1% or less.

According to the present invention, in the collected developer, the differential amount increases as described above, but the second type is replaceable.
As a characteristic of the developer in the second container, by selecting the amount of fine powder as described above, an ideal particle size distribution can be obtained in the mixed developer of the collected developer and the new developer from the second container. Can be controlled to any value. Therefore, an image with excellent image quality can be stably formed.

Further, the present invention is characterized in that the characteristics of the developers accommodated in the second and third containers are different from each other.

According to the present invention, when the second to third containers are replaced by considering the characteristics of the new developer in the replaceable second and third containers. In addition, it becomes possible to stably form an image with excellent image quality.

[0023]

[0024]

[0025]

[0026]

[0027]

The present invention is also a method for forming an image by developing a latent image on an image bearing member by attaching a developer to the latent image on the image bearing member by a developing device, transferring the developer to a transfer material and fixing the image. In the image forming method, the developer is supplied from the replaceable container to the developer, and the developer collected by the collector from the image carrier is supplied to the developing container housed in the first container. When the developer is exhausted, the supply of the collected developer to the developing device is started, and when the collected developer is supplied to the developing device, the first container is replaced with the second container, The characteristics of the developer contained in the first container and the characteristics of the developer contained in the second container are selected so as to be different from each other, and the characteristics are the average particle size and the particle size. At least one of distribution and fine powder amount Which is the image forming method characterized.

According to the present invention, the developer is provided with the new developer in the container and the collected developer.
At this time, when the developer in the first container runs out, supply of the collected developer to the developing device is started. When the collected developer is supplied to the developing device, the container is replaced from the first container to the second container. Here, the developer characteristics of the first container and the developer characteristics of the second container are selected so as to be different from each other, and the characteristics are among the average particle size, the particle size distribution, and the fine powder amount. At least one of the above.
With such an image forming method, it is possible to stably form an image with excellent image quality.

[0030]

1 is a sectional view showing an image forming apparatus 1 according to an embodiment of the present invention. The photoconductor drum 2 of the image forming apparatus 1 adopting the two-component developing method is an image carrier, has a photoconductive photosensitive layer, and is configured to be rotatable in the direction S1. An electrostatic latent image is formed by the exposure device 3 on the photoconductor drum 2 charged to a predetermined potential by the charging device 15 described later. As the exposure device 3, for example, a laser system using a semiconductor laser, a system using an LED (light emitting diode) array, or a system using a liquid crystal shutter is adopted.

A developer is attached to the formed electrostatic latent image by the developing device 4 arranged downstream of the exposing device 3 in the drum rotation direction to develop the electrostatic latent image. The developer contains a binder resin as a main component and a toner having a fluidizing agent or the like on its surface, a colorant, a charge control agent, and the like. New toner is replenished in the accommodating portion 5 of the developing device 4 from a replaceable toner hopper 6. Further, the collected toner collected as described later is replenished. The toner is a developing roller 8 provided in the developing device 4 and arranged to face the photoconductor drum 2, and the direction S2 is opposite to the rotation direction S1 of the photoconductor drum 2.
It is supplied onto the photosensitive drum 2 by the developing roller 8 which is configured to be rotatable.

The toner adhering to the photoconductor drum 2 is transferred onto a paper sheet or an O sheet by a transfer / separator 10 which is arranged downstream of the developing device 4 in the drum rotation direction so as to face the photoconductor drum 2.
It is transferred and fixed on a transfer material such as an HP sheet. The transfer material is transported to a predetermined transfer position by the transport roller 9. Either one of an electrostatic transfer method and a bias transfer method is applied as the transfer method.

A toner collector 7 is arranged downstream of the transfer / separator 10 in the drum rotation direction to collect the toner remaining on the photosensitive drum 2 after transfer and fixing.
The toner collector 7 includes a cleaning blade 12 that contacts the photosensitive drum 2, and the blade 12 cleans and collects residual toner. The collected toner is transferred to the storage unit 5 of the developing unit 4 by the collected toner conveying device 13 realized by a screw conveyor or the like included in the toner collecting unit 7.
Given to.

A static eliminator 14 for eliminating charges remaining on the surface of the photoconductor drum 2 is arranged on the downstream side of the toner collecting device 7 in the drum rotation direction, and a surface of the photoconductor drum 2 is further located on the downstream side. A charging device 15 for charging the battery to a predetermined potential is arranged.

In addition to the two-component developing method, there are magnetic, non-magnetic, one-component, contact and non-contact developing methods, and the present invention can be applied to any method.

As the binder resin for the toner used, a homopolymer of styrene such as polystyrene and its substitution products,
Examples thereof include styrene-based copolymers such as styrene-acrylic copolymers, acrylic resins, methacrylic resins, polyester resins and epoxy resins, but are not limited to these resins and resins generally used as toner resins. Are all available.

As the colorant, in addition to carbon black, for example, nigrosine dye, aniline blue, chalco oil blue, chrome yellow, ultramarine yellow, methylene blue, DuPont oil red, quinoline yellow, methylene blue chloride, phthalocyanine blue, malachite. Green, oxalate, lamp black, rose bergal and mixtures thereof can be used.

Further, examples of the positive charge control agent include nigrosine compounds and organic quaternary ammonium salts, but the positive charge control agent is not limited to these, and those generally used as the positive charge control agent for toner are All are available.

Further, an anti-sticking agent can be mixed. As the anti-adhesive agent, for example, polyethylene wax, polypropylene wax and paraffin wax can be used, and these are extremely effective for improving the releasability of the toner from the fixing roller.

Further, examples of the charge control agent include fine powders of silica and titanium oxide, but the charge control agent is not limited thereto, and any of those generally used as a charge control agent for toner can be used. For example, the fine silica powder is used in an amount of 0.01 to 1.6 parts by weight, preferably 0.1 to 1.0 parts by weight, based on 100 parts by weight of the toner.

In the case of non-magnetic toner, examples of the carrier to be used include magnetic powders such as iron powder, ferrite powder and nickel powder. The carrier is preferably coated with a resin or a silicone compound and a fluororesin. Such carriers also have a charge control function.

As the silicone compound, for example, a mixture of silicone resin, silicone compound, fluorine resin and acrylic resin can be used. As the fluororesin, polyvinyl fluoride, polyvinylidene fluoride, or a copolymer of vinylidene fluoride and an acrylic monomer can be used.

Since the image forming apparatus 1 of the present embodiment adopts the two-component developing system, the two-component developer of toner and carrier is used, and the photosensitive member which is a cylindrical sleeve containing the multi-pole magnet from the developing roller 8. Developed on the drum 2 with a mag brush. An electric charge is imparted to the toner mainly by contact with the carrier.

Table 1 shows toner particle size distribution data. FIG. 2 is the graph. In addition, Table 1 shows a volume average particle diameter D50 (μm), a particle diameter ratio (%) in the range of particle diameters of 2.02 μm to 4.91 μm, a fine powder amount ratio (%), and a particle diameter including the volume average particle diameter. The ratio (%) of distribution 3ch is shown. Particle size distribution 3ch means a particle size of 9.552 μm to 14.89 μm
The range is m. The measuring method of the particle size distribution is described in JP-A-6-5.
Similar to No. 9501.

[0045]

[Table 1]

It can be seen from Table 1 and FIG. 2 that the recovered toner has an average particle diameter D50 smaller than that of the toner contained in the first toner popper 6 by 1.6 μm, and the ratio of the amount of fine powder increases by about 3 times. I understand. Table 2 shows the evaluation results of the image quality when the image formation is performed using the recovered toner.

[0047]

[Table 2]

It can be seen from Table 2 that the use of the recovered toner causes a lot of background fog and toner scattering, which inevitably affects image quality and toner loss. Therefore, the following studies were conducted in order to solve these problems.

(Example 1) As the toner, an adjusted two-component toner was used. In the image forming apparatus 1, the collected toner is returned to the accommodating portion 5 of the developing device 4 by the collected toner conveying device 13 which is a pipe provided with a conveying screw inside, and is gently stirred with the new toner accommodated in the toner hopper 6. A modified copying machine SF2050 manufactured by Sharp Co., which was modified so as to be discharged from the developing roller 8, was used. While replenishing the toner successively, 250,000 sheets of image were continuously formed at an image forming speed of 20 sheets of A4 size sheet per minute.

Further, the toner composition before the external addition step is 90 parts by weight of polystyrene as a binder resin, 5 parts by weight of carbon black as a coloring agent, 2 parts by weight of a charge control agent, and 3 parts of polyethylene wax as an anti-adhesive agent. It has parts by weight.
Toner is mixed by stirring each material with a mixer, kneading the resulting mixture with a screw extruder under heating, coarsely pulverizing the obtained kneaded product, and finely pulverizing the obtained coarsely pulverized product with a jet pulverizer. Then, the obtained finely pulverized product was classified to prepare it. The external additive treatment is performed by stirring and mixing an external additive of 0.01 to 1.6 parts by weight of silica fine powder and 0.2 parts by weight of magnetite with a mixer with 100 parts by weight of the toner before the treatment. It was

Table 3 shows the evaluation results of the image quality at the time of 25,000 sheets when the toner having the same characteristics as the toner contained in the first toner popper 6 is replenished to form an image.

[0052]

[Table 3]

In this case, the image quality gradually deteriorates after 10,000 sheets, and the result as shown in Table 3 is obtained at the time of 25,000 sheets. Further, in Table 4, when the toner in the first toner popper 6 is exhausted and the toner reuse is started, the collected toner is supplied to the storage unit 5, and the collected toner starts to be supplied to the storage unit 5, the toner popper 6 The following shows the evaluation results of the image quality at the time of 25,000 sheets when the images are formed by exchanging the sheets. At this time, the characteristics of the toner before and after replacement,
That is, the average particle size and particle size distribution of the toner are selected to be different.

[0054]

[Table 4]

From Tables 1 and 4, the high reflected image density was maintained even after the image formation of 25,000 sheets, fog and toner scattering did not occur, and it was stable and high as at the start of image formation. It can be seen that the image quality is maintained. After forming 25,000 sheets of image, the amount of toner consumed was examined using an A4 size sheet on which characters were formed with an image area ratio of 7%. The average toner consumption was 0.028 g / sheet. The transfer rate was 80% to 92%. The transfer rate was 94% to 95% when the toner was not reused.

It should be noted that the toner consumption amount can be detected by, for example, a dot counter, and the replacement time of the toner hopper 6 can be determined based on the detection result. In the case of digital image formation, since the image is composed of dots by the laser, the toner consumption amount per dot can be measured in advance and the toner consumption amount can be detected from the number of dots (printing rate). Further, the toner hopper 6 may be provided with a remaining amount detecting means to detect the toner consumption amount. For example, when the toner remaining amount decreases, the transmission window is not shielded, and this is detected by a detection unit such as a sensor.

(Example 2) The toner, the toner manufacturing method, the image forming apparatus 1 and the image forming conditions were the same as in Example 1. In order to replace the toner hoppers 6 having different toner characteristics at appropriate timing, the toner amount of the first toner hopper 6 was determined as follows.

Amount of toner in the first toner hopper = number of images formed × amount of toner consumed by development per image formation Number of images formed = volume of recycled portion / amount of recovered toner per image formed Here, of the recycled portion The volume is the amount of collected toner existing in the toner collecting device 7 and the collected toner conveying device 13 at the time when the collected toner is supplied to the containing portion 5. In the first toner hopper 6 having the amount of toner thus determined, the collected toner is reused and the developing device 4
When returning to the accommodation section 5 of No. 3, the new toner is completely consumed. Therefore, if the toner hopper 6 is replaced at this timing,
The characteristics are almost constant even if the toner is reused, and a stable high-quality image can be obtained.

In particular, if the toner hopper 6 is a replaceable cartridge type, replacement by the user becomes easy. Further, the toner amount of the second and subsequent toner hoppers 6 does not have to be the same as that of the first toner, and may be appropriately set according to the size of the image forming apparatus 1 or the developing device 4, the maintenance cycle, and the like. For example, by increasing the amount of toner in the second and subsequent toner hoppers 6 to be larger than the amount of toner in the first toner hopper 6, it is possible to reduce the replacement frequency of the toner hopper 6 and prolong the maintenance cycle. Further, the first toner hopper 6 may be included in the image forming apparatus 1 or the developing device 4 at the time of shipment. This makes it easy to distinguish between the first toner hopper 6 and the second and subsequent toner hoppers 6.

(Embodiment 3) The toner, the method for producing the toner, the image forming apparatus 1 and the image forming conditions were the same as in Embodiment 1. The characteristics of the toners contained in the replaceable toner hoppers 6, especially the average particle diameter, were selected to be different from each other. The average particle size was adjusted by selecting the processing conditions when the coarsely pulverized product of the kneaded product was finely pulverized by a jet pulverizer. By changing the average particle diameter, it is possible to control the change in the characteristics due to the reuse of the toner, and it is possible to obtain a stable and high quality image.

From Table 1, it can be seen that the volume average particle diameter D50 of the toner in the first toner hopper 6 is 10.9 μm, whereas the volume average particle diameter D50 of the recovered toner is 9.3 μm. Therefore, by selecting the volume average particle diameter of the second toner hopper larger than that of the first toner hopper, it is possible to control the change due to the reuse of the toner.

Table 5 shows the evaluation results of the image quality at the time of 25,000 sheets when the volume average particle diameter D50 of the toner of each toner popper 6 is changed and mixed with the recovered toner in a one-to-one manner to form an image. Shown as (1) to (4).

[0063]

[Table 5]

From Table 5, the volume average particle diameter D50 is 12.8.
It can be seen that when set to μm, the reflection image density, background fog, and toner scattering amount are all good. Therefore, the average particle size of the toner in the second toner hopper 6 is set to 1.
It can be seen that it is preferable to increase in the range of 5 μm or more and 2 μm or less.

(Example 4) The toner, the toner manufacturing method, the image forming apparatus 1 and the image forming conditions were the same as in Example 1. The characteristics of the toner in each replaceable toner hopper 6, especially the particle size distribution, were selected to be different from each other. The particle size distribution was adjusted by selecting the processing conditions when the coarsely pulverized product of the kneaded product was finely pulverized by the jet pulverizer, similarly to the average particle size. By changing the particle size distribution, it is possible to control the change in the characteristics due to the reuse of the toner, and it is possible to obtain a stable and high-quality image.

From Table 1, the ratio of the particle size distribution 3ch including the volume average particle diameter D50 of the toner in the first toner hopper 6 is 80.6%, whereas the volume average particle diameter D50 of the recovered toner is included. It can be seen that the ratio of the particle size distribution 3ch is 72.7%. Therefore, by selecting the ratio of the particle size distribution 3ch of the second toner hopper larger than that of the first toner hopper, it is possible to control the characteristic change due to the reuse of the toner.

Table 6 shows the evaluation results of the image quality at the time of 25,000 sheets when changing the ratio of the toner particle size distribution 3ch of each toner popper 6 and mixing the collected toner 1: 1. Shown as (5) to (9).

[0068]

[Table 6]

From Table 6, the ratio of particle size distribution 3ch is 85%.
It can be seen that when the above settings are made, the reflection image density, background fog, and toner scattering amount are all good. Therefore, the toner particle size distribution of the second toner hopper 6 is 3ch.
It is understood that the ratio of is preferably 85% or more.

(Embodiment 5) The toner, the method for producing the toner, the image forming apparatus 1 and the image forming conditions were the same as in Embodiment 1. The characteristics of the toner of each replaceable toner hopper 6, especially the amount of fine powder, were selected so as to be different from each other. By changing the amount of fine powder, it is possible to control the characteristic change due to the reuse of the toner, and it is possible to obtain a stable and high-quality image.

It can be seen from Table 1 that the fine powder amount ratio of the toner in the first toner hopper 6 is 2.7%, whereas the fine powder amount ratio of the recovered toner is 8.7%. Therefore, by selecting the amount of fine powder of the second toner hopper smaller than that of the first toner hopper, it is possible to control the characteristic change due to toner reuse.

Table 7 shows the evaluation results of the image quality at the time of 25,000 sheets when changing the fine powder amount ratio of the toner of each toner popper 6 and mixing it with the recovered toner in a ratio of 1: 1. )-(14).

[0073]

[Table 7]

From Table 7, it can be seen that when the fine powder amount ratio is set to 1.0% or less, the reflection image density, the background fog and the toner scattering amount are all good. Therefore, it is understood that it is preferable to set the fine powder amount ratio of the toner in the second toner hopper 6 to 1.0% or less.

Although the third to fifth embodiments are characterized in that the toner characteristics of the respective toner hoppers 6 are set to be different, the toner hopper 6 may be replaced at the time determined in the first and second embodiments. I do not care. As a result, a more stable and high-quality image can be obtained.

(Example 6) The toner, the method for producing the toner, the image forming apparatus 1 and the image forming conditions were the same as in Example 1. The toner characteristics of each replaceable toner hopper 6 were selected to be different from each other. Here, the toner characteristics of the second and third toner hoppers 6 are changed. The property of the toner to be changed is at least one of the average particle size, the particle size distribution, and the fine powder amount described above. Specific values are shown in Table 1. As a result, it is possible to control the characteristic change due to the reuse of the toner and obtain a stable and high-quality image.

Although the toner characteristics of the second and third toner hoppers 6 are changed in the sixth embodiment, the toner characteristics of the first, second, third, ... However, in reality, the change in toner characteristics is 1
Since it is remarkable in the 3rd to 3rd lines and does not change significantly after that, it is effective to change the toner characteristics in the 1st to 3rd lines in order to obtain a stable and high-quality image.

[0078]

As described above, according to the present invention, the average particle diameter, the average particle diameter, and the developer characteristics of each of the containers that can be exchanged are
Since at least one of the particle size distribution and the amount of fine powder is made different from each other, the change in the characteristic caused by the reuse of the developer is controlled in consideration of the developer characteristic of the second container, for example. Therefore, it is possible to stably form an image with excellent image quality.

[0079]

Further, according to the present invention, by optimizing the average particle size of the developer, the average particle size in the mixed developer of the collected developer and the developer from the second container can be controlled. Therefore, it becomes possible to stably form an image of excellent image quality.

According to the present invention, the particle size distribution in the mixed developer of the collected developer and the developer from the second container is controlled by optimizing the particle size distribution of the developer. Therefore, it becomes possible to stably form an image of excellent image quality.

According to the present invention, the particle size distribution in the mixed developer of the recovered developer and the developer from the second container is controlled by optimizing the amount of fine powder of the developer, It is possible to stably form an image with excellent image quality.

Further, according to the present invention, by taking the developer characteristics of the second and third containers into consideration, an image having excellent image quality can be stably obtained even when the third container is replaced. Can be formed.

[0084]

[0085]

[0086]

Further, according to the present invention, when the new developer in the first container is used up, the supply of the collected developer to the developing device is started, and when the collected developer is supplied to the developing device. The first container is replaced with the second container, and the developer characteristic of the first container and the developer characteristic of the second container are selected to be different from each other. The characteristic is at least one of average particle size, particle size distribution, and fine powder amount. Therefore, it becomes possible to stably form an image with excellent image quality.

[Brief description of drawings]

FIG. 1 is a sectional view showing an image forming apparatus 1 according to an embodiment of the present invention.

FIG. 2 is a graph showing a toner particle size distribution.

[Explanation of symbols]

1 Image forming device 2 photoconductor drum 3 exposure unit 4 developing device 5 accommodation 6 Toner hopper 7 Toner collector 8 developing roller 10 Transfer / separator 12 cleaning blade 13 Collected toner transport device

─────────────────────────────────────────────────── --- Continuation of the front page (56) References JP-A-8-69177 (JP, A) JP-A-8-69178 (JP, A) JP-A-8-76404 (JP, A) JP-A-5- 289462 (JP, A) JP-A-2-157765 (JP, A) JP-A-9-120207 (JP, A) JP-A-10-10947 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) G03G 15/08 113 G03G 15/08 507 G03G 21/00 510 G03G 21/10

Claims (6)

(57) [Claims] 1. An image carrier for carrying a latent image, a developing device for adhering a developer to the latent image on the image carrier for development, and a replaceable container for accommodating a new developer supplied to the developing device. In an image forming apparatus including a container and a collector that collects the developer on the image carrier and supplies the developer to the developing device, the characteristics of the developer housed in each replaceable container are the average particle size and the particle size. An image forming apparatus, wherein at least one of a diameter distribution and an amount of fine powder is different from each other. 2. The average particle size of the developer contained in the second container is 1.5 μm or more and 2.0 μm with respect to the average particle size of the developer contained in the first container. The image forming apparatus according to claim 1, wherein the image forming apparatus is large in the following range. 3. The ratio of the amount of the developer having a particle size in the range of 9.552 μm to 14.89 μm to the total amount of the developer contained in the second container is 85% or more. The image forming apparatus according to claim 1. 4. The ratio of the amount of the developer having a fine particle size in the range of 2.02 μm to 4.91 μm to the total amount of the developer contained in the second container is 1% or less. The image forming apparatus according to claim 1, wherein the image forming apparatus is an image forming apparatus. 5. The image forming apparatus according to claim 1, wherein the characteristics of the developers contained in the second and third containers are different from each other. 6. A method for forming an image by applying a developer to a latent image on an image bearing member by a developing device to develop the latent image, transferring the developer to a transfer material and fixing the image. In the image forming method, in which a new developer is supplied from the replaceable container and the developer collected by the collecting device on the image carrier is supplied, the developer contained in the first container disappears. Then, the supply of the collected developer to the developing device is started, and when the collected developer is supplied to the developing device, the first container is replaced with the second container, and the first container is replaced with the first container. The characteristics of the developer contained in the second container and the characteristics of the developer contained in the second container are selected to be different from each other, and the characteristics are the average particle size, the particle size distribution and the fine powder. Characterized by being at least one of a quantity Image forming method.