JP2003195635A - Developing device, image forming apparatus and processing cartridge - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reduce toner which remains unconveyed in a developing device with a sheet-shaped member installed in a slanted surface. <P>SOLUTION: The angle of a position where the sheets-shaped member is fixed is made greater than the slanted surface and also greater than an angle of repose of the toner. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a developing device used in a copying machine, a printer or the like adopting an electrophotographic system, an image forming apparatus including the developing device, and a process cartridge detachable from the image forming apparatus. is there.

[0002]

2. Description of the Related Art A general example of a developing device adopting an electrophotographic system is shown in FIG.

In many cases, a developing device is provided with a developer carrying member 31 for carrying the developer from the developer container 2 containing the developer to a developing area for developing. In addition to the role of loosening the developer in the developer container, this member also has the role of circulating the developer in the developer container and from the development area to the developer container, which is a very important role. Can be said to have fulfilled. Also,
In order to increase the amount of developer that can be stored in the developer container, an inclined surface 17 is often provided behind the movable region of the developer transport member, as described in JP-A-5-35095.

The operation of the developing device shown in FIG. 8 will be briefly described. The developer 11 which has been conveyed to the developing area through the opening as the developer conveying member 31 rotates in the direction of rotation 24 of the developer conveying member is carried on the developer carrier 3 and is conveyed by the blade 10. The latent image formed on the image carrier (not shown in the drawing) is developed under the influence of triboelectric charging and layer thickness regulation. After that, the image is transferred to a transfer material such as paper, and an image is obtained through a fixing process on the transfer material.

In the example shown here, the angle of the normal slope 17 with respect to the horizontal plane is set to be equal to or greater than the repose angle of the developer,
The configuration is such that the developer is dropped from the inclined surface 17 to the region where the developer transport member 31 passes. Therefore, the developer can be sent to the movable region of the developer carrying member 31 without adding a new carrying member. Further, it is not necessary to enlarge the developer transport member 31.

The angle of repose of the developer is the angle of the ridge (θ in the figure) formed at the bottom when the developer is sieved off from the top as shown in FIG. Below this angle,
The developer does not slip off under its own weight.

[0007]

On the other hand, in order to increase the amount of developer that can be accommodated in the case of FIG.
As described in Japanese Patent No. 237576, a sheet-shaped member 18 is provided on the slope 17, and one end of the sheet-shaped member 18 is periodically engaged with the developer conveying member 31 to vibrate the sheet-shaped member 18, and the vibration is used. There is also an example in which the developer can be sent to the movable region of the developer transport member 31 even if the slope angle is less than the repose angle of the developer. An example is shown in FIG.
It was shown to. Since the constraint on the slope angle (α in the figure) can be significantly relaxed compared to the example shown above, the degree of freedom in designing the container arrangement is increased, and the volume can be expanded below the slope.

In this example, not only the developer on the slope can be easily dropped, but also vibration is constantly applied, so that the developer on the slope can be prevented from being easily packed, which is an excellent structure. I can say.

On the other hand, in order to exert the effect of vibration over the entire slope, it is necessary to fix the upper end of the side not contacting the developer carrying member 31 to the container. At the same time, if the developer enters between the sheet-shaped member and the slope, the desired vibration may not be obtained at the time of engagement with the developer transport member. Not preferable.

Considering the engagement of the developer carrying member for each rotation cycle, it is necessary to make the sheet-like member difficult to peel from the container. That is, it is necessary that the sheet-shaped member is firmly fixed to the container. For this reason, when the fixing width is set to about several mm in the lateral direction, the developer conveying member 31 is attached to the sheet-shaped member fixed to the container.
Since the vibration due to the contact with is not transmitted, the developer may remain on the fixed part.

Therefore, it is an object of the first and second aspects of the present invention to increase the amount of developer that can be accommodated and further reduce the amount of developer that remains unused without impairing the effect of the sheet-shaped member. It is an object of the present invention to provide a developing device capable of

The objects of the third and fourth inventions according to the present invention are:
An object of the present invention is to provide an image forming apparatus and a process cartridge that include a developing device that reliably conveys a developer.

[0013]

In order to achieve the above object, a first invention according to the present invention is a developing device comprising a sheet-like member on a slope having an angle smaller than the repose angle of the developer. The angle of the container wall fixed position with respect to the horizontal plane is larger than the angle of the slope and the repose angle of the developer. Even if vibration is not applied at the fixed position of the sheet-shaped member, the sheet-shaped member easily falls, so that it is possible to prevent the developer from remaining. In addition, by arranging the fixing position on a plane other than the same plane as the slope, the vibration direction of the sheet-shaped member and the direction of loosening the sheet-shaped member can be deviated, which leads to stabilization of the sheet-shaped member.

According to the second aspect of the present invention, the angle of the slope of the developer container is less than the angle of repose of the developer, so that the angle of the slope of the container can be loosened, so that the volume of the developer container can be expanded. The amount of developer that can be accommodated can be increased.

A third invention according to the present invention is the first or second invention.
An image forming apparatus using the developing device of the invention. The image forming apparatus can reliably carry the developer in the container.

A fourth invention according to the present invention is the first or second invention.
The process cartridge is characterized by being detachable from the main body using the developing device of the invention. It is possible to provide a process cartridge that can reliably carry the developer while making the most of the advantages of handling and maintenance.

Further, in more detail, the present invention can solve the above problems by the following constitution.

(1) At least a developer carrying member, a developer carrying member that contains the developer and has a rotation axis parallel to the developer carrying member, and that carries and agitates the developer, and is close to the passage area. In a developing device including a developer container having a sloped surface at the rear of the container, a sheet-shaped member made of a flexible material and periodically engaged with a developer conveying member is provided on the sloped surface, and the fixing position of the sheet-shaped member is provided. In the developing device, the angle of the container wall surface with respect to the horizontal plane is larger than the angle of the slope and the angle of repose of the developer.

(2) The developing device as described in (1) above, wherein the angle of the inclined surface of the developer container with respect to the horizontal plane is equal to or less than the repose angle of the developer.

(3) An image forming apparatus including the developing device described in (1) above, wherein the developing device develops the latent image bearing member to form an image.

(4) The developing device according to (1) above is included,
A process cartridge which is removable from the main body of the image forming apparatus.

[0022]

BEST MODE FOR CARRYING OUT THE INVENTION (First Embodiment) First, a first embodiment will be described. FIG. 2 shows a cross-sectional view of the image forming apparatus of this embodiment. This image forming apparatus includes a developing device 1, a photosensitive drum 5 which is a latent image carrier, a charging roller 6 which is a charging means arranged around the photosensitive drum, a cleaning means 12 which cleans the surface of the photosensitive drum, and
The transfer unit 13, the fixing unit 14, and the exposure device 15 are included. In this case, the transfer material transport path is as shown by arrow 23.

The developing device 1 has a developer container 2 for containing a developer 11. The developer container 2 has an opening so that a part of the developing sleeve 3 carrying the developer is exposed outside the container. Development sleeve 3
Is rotated in the direction of 21 by a drive mechanism (not shown). Further, the magnet roller 4 is provided inside the developing sleeve.
Is provided, but it is not rotated by driving, is held at a fixed position, and the direction of the magnetic pole is always kept in the same direction. Development bias 7 for the developer carrier
The DC bias 8 and the AC bias 9 are superposed and applied. In the developing device, an elastic blade 10 for regulating the layer thickness of the developer and giving an electric charge necessary for development is attached to the opening. Developer 11
Is a one-component magnetic developer, and reverse development is performed.

The photosensitive drum 5 is arranged in a non-contact manner at a position facing the developing sleeve at a constant interval, and rotates in the direction of 22 when driven. A charging roller 6 and a cleaning blade 12 are arranged around the latent image carrier in contact with the photosensitive drum. The charging roller charges the photosensitive drum. The cleaning blade 12 uses urethane rubber supported by a metal plate, and cleans the untransferred developer remaining on the surface of the photosensitive drum. A roller method is used as the transfer means.

Next, the operation of the image forming apparatus will be described with reference to FIG. First, the charging operation of the charging roller 6 uniformly charges the surface of the photosensitive drum 5. Then, the exposure device 15 such as a laser performs exposure 25 based on the image signal to form a latent image on the latent image carrier. Further, the developer 11 in the developer container 2 is taken into the developing sleeve 3 through the opening by the developer conveying member 31 and is conveyed. Then, while being regulated by the blade 10 for the layer thickness, they are simultaneously charged and sent to the developing area. Then, the developing bias 7 applied to the developing sleeve 3 causes the developer 11 fed into the developing area to fly onto the photosensitive drum 5. Here, the developer that does not retain a sufficient electric charge necessary for development remains on the developing sleeve, or even if the developer flies onto the photosensitive drum, the magnetic force of the magnet roller and the pull-back component of the AC bias cause the developer on the developing sleeve. Be pulled back to. on the other hand,
The developer having a sufficient charge makes the electrostatic latent image visible and completes the developing operation.

After that, when the visible image portion reaches the area facing the transfer roller, the operation of the transfer means 13 by the roller is performed on the transfer material conveyed as shown in FIG. 2 in synchronization with the image on the photosensitive drum. Then, the image is obtained by passing through the fixing means 14 and the image. on the other hand,
The developer remaining on the photosensitive drum without being transferred is collected in the cleaner container 16 by the cleaning blade 12.

The process conditions of this image forming apparatus are shown below. The developer carrying member is a φ16 non-magnetic aluminum sleeve, and the surface is coated with a resin layer containing conductive particles. The distance at the facing portion between the latent image carrier and the developer carrier is 200 μm. The charging potential Vd of the latent image carrier is -7.
00V, the photosensitive potential Vl by exposure is -100V, the DC component Vdc of the developing bias is -450V, and the waveform of the AC component is Vp-p (peak-to-pe) here.
ak voltage) = 1.2 kV rectangular wave. The frequency of the AC component was 1.4 kHz. The magnet roller inside the developer carrier has an S pole in the direction facing the latent image carrier, and plays a role of returning excess developer from the latent image carrier or developer flying to the white background. Further, as the elastic blade, silicone rubber, phosphor bronze plate or the like can be used, but in the present embodiment, the elastic blade using urethane rubber supported by a sheet metal as a material is used. The process speed (image forming speed) was 70 mm / sec.

The developer has an average particle size of 7.5 μm.
A magnetic toner containing m and a magnetic substance containing a negatively charged styrene acrylic resin as a main component was used. The magnetic substance is in the range of 30 to 200 parts, and particularly preferably 50 to 150 parts, relative to 100 parts of the resin. In this embodiment, 1
It was used by using 00 parts. The angle of repose of the developer used in this example was 40 °.

Regarding the structure of the developer container 2 of the present embodiment,
Details are shown in FIG. A developer carrying member 31 is disposed in the developer container 2, and the developer is carried from the developer container 2 through the opening 17 to the developer carrying member by rotating in the rotation direction 24 of the developer carrying member. Plays a role in sending in.

In this embodiment, the developer carrying member 31 is used.
Φ processed into a crank shape as shown in Fig. 3
2 SUS304 rod 32 with sheet metal 3
3 was attached, and a conveying blade 34 made of PET having a thickness of 150 μm was attached to the sheet metal. The rotation diameter was φ26 and the rotation speed was 9 rpm.

The portion connected to the opening of the developer container has an arc shape corresponding to the rotation region of the developer transport member 31. In addition, a slope 17 is provided behind the developer container and connected to the rotation region of the developer transport member 31. Slope 17
The angle between the horizontal plane and the horizontal plane (indicated by α in the figure) is 30 °, which is 10 ° smaller than the angle of repose of the developer used. The slope 17 is 2m from the tangent to the arc.
It is arranged with a step on the upper side of m.

Further, in this embodiment, the sheet-like member 18 is provided on the upper portion of the slope 17. Regarding the sheet-like member 18, considering that the sheet-shaped member 18 is deformed and vibrated by contact with the developer transporting member 31, and that the rotation operation of the developer transporting member 31 is not hindered, etc. It is desirable that the rigidity is low. Here, the sheet-shaped member 18
50 μm thick PET is used for the fixing, and the fixing member 20 is used for fixing.
The upper end was fixed using (eg adhesive). The fixed width was 5 mm, and the slope angle (shown by β in the figure) of the fixed position 19 with respect to the horizontal plane was 70 °. The sheet-like member 18 is bent just below the fixed position 19 to follow the slope. Further, the tip end of the sheet-shaped member 18 projects by 5 mm with respect to the rotation region of the developer transport member 31, and is periodically engaged with the tip end of the developer transport member 31 and deformed by the step. It will vibrate. The developer carrying member 31 is not in contact with the container except for being in contact with the sheet-like member 18.

The effects of this embodiment will be described using a comparative example having a very similar structure. The structure is shown in FIG. The configuration is the same as that of this embodiment except that a fixing position 19 is provided at a width of 5 mm on the uppermost part of the slope and the same sheet-like member 18 as that of this embodiment is bonded. According to a study by the inventors of the present invention, in the case of the comparative example, the developer may remain as shown in FIG. 4, and when examined, it is found that the developer starts to remain near the fixing position of the sheet-shaped member. I understood. In contrast,
In this example, there was almost no remaining as shown in FIG. 4, and a stable effect was exhibited. Regarding the remaining positions of the comparative example, there is a tendency that the sheet-shaped members start to remain from the fixed position, and the amount thereof was unstable.

Therefore, in this embodiment, since the sloped portion 17 is a free end, vibration is applied so that the stationary portion 19 that cannot vibrate easily falls freely, so that the developer is spread over the entire sheet-like member 18. It can be seen that the developer can be more reliably fed to the movable region of the developer transport member 31 in the present embodiment as compared with the comparative example because the configuration in which the developer does not remain is possible. In addition to the adhesive described in the present embodiment, various methods having a fixed width such as double-sided tape and screwing can be adopted, and the same effect is exhibited.

Further, since the vibration direction of the sheet-shaped member 18 due to the engagement with the developer conveying member 31 is deviated from the vibration direction for loosening the fixing, the sheet-shaped member 1 is vibrated.
The fixing of No. 8 is not easily damaged, and it can be said that this point is also excellent.

In the state where the sheet-like member 18 is not provided, the remaining amount is considerably larger than that of the comparative example as shown in FIG. 5, and in the case where the slope angle is smaller than the repose angle of the developer. It can be seen that the effect of the sheet-shaped member 31 is very large.

In the present embodiment, the fixed position is provided directly above the slope, but in an actual developer container, a flat surface with a certain width cannot be ensured, so there may be a case where the fixed position cannot be provided directly above. Therefore, as shown in FIG. 6, the bent portion may be extended upward and fixed at its upper end.

The numerical values and materials shown in this embodiment are not particularly limited to the structure described in this embodiment as long as the effects are not impaired.

(Second Embodiment) Next, a second embodiment will be described. In the first embodiment, the angle was largely different between the fixed position and the slope, so it was necessary to bend the sheet-shaped member. On the other hand, a major feature of this embodiment is that a curved surface is formed from the slope portion to the fixed position so that the angle is continuously changed so that the sheet-shaped member follows the slope without bending. The embodiment is shown in FIG.

In this embodiment, the same thickness 50 as in the first embodiment is used.
As a result of an examination using μm PET, it was confirmed that the effect was equivalent to that of the first embodiment and that the effect was maintained. Also in this embodiment, the fixing of the sheet-shaped member is deviated from the displacement direction of the sheet-shaped member, and the fixing is less likely to be unstable.

If the degree of change in the angle is increased, the slope may not be copied, so it is preferable to use a sheet that is as thin as possible. Furthermore, the slope angle is 90 °
If it becomes larger than that, the sheet-like member floats on the wall surface of the container and does not follow the container. Therefore, when the present embodiment is adopted, the angle of the fixed position with respect to the horizontal plane is 90 degrees.
It is preferable that the angle is not more than °.

Considering the labor of bending and adjustment to a desired angle, this one can be constructed more simply, so
It can be said that it is superior to the examples.

[0043]

As described above, the first aspect of the present invention
According to the invention, since it is possible to make the developer less likely to remain even at the fixed position of the sheet-shaped member, it is possible to provide a developing device that can stably convey the developer without impairing the effect of the sheet-shaped member. . Further, since the displacement direction of the sheet-shaped member and the direction of peeling the fixing can be shifted,
It also leads to stabilization of the sheet-shaped member.

According to the second aspect of the present invention, since the angle of the slope can be reduced, the volume of the developer container can be increased and the amount of developer that can be contained can be increased. .

According to the third aspect of the present invention, it is possible to provide an image forming apparatus that makes it difficult for the developer to remain in the container.

According to the fourth aspect of the present invention, it is possible to make the process cartridge excellent in handleability for the user while preventing the developer from remaining in the container.

[Brief description of drawings]

FIG. 1 is a cross-sectional view around a developing device according to a first embodiment.

FIG. 2 is a sectional view of the image forming apparatus according to the first embodiment.

FIG. 3 is a configuration of a developer carrying member according to the first embodiment.

FIG. 4 shows how the developer remains in a comparative example.

FIG. 5: A state in which the developer remains without the sheet-shaped member

FIG. 6 is a sectional view of a developing device according to a modified example of the first embodiment.

FIG. 7 is a sectional view of the developing device according to the second embodiment.

FIG. 8 is a sectional view of a conventional developing device.

FIG. 9: Method for measuring repose angle of developer

FIG. 10 is a sectional view of another conventional developing device.

[Explanation of symbols]

1 Development device 2 developer container 3 developer carrier 4 magnet roller 5 Latent image carrier (photosensitive drum) 6 charging roller 7 Development bias 8 Development bias DC component 9 Development bias AC component 10 Developer regulating member (elastic blade) 11 Developer 12 cleaning blade 13 Transfer means 14 Fixing means 15 Exposure equipment 16 cleaner container 17 slope 18 Sheet-shaped member 19 Sheet-like member fixing position 20 fixing member 21 Direction of rotation of developer carrier 22 Direction of rotation of latent image carrier 23 Transfer material transport direction 24 Direction of rotation of developer transport member 25 Exposure from exposure equipment 31 developer transport member 32 crank shaped rod 33 Conveyor blade attachment seat surface 34 Transportation

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Claims (4)

[Claims] 1. A developer carrier, at least a developer carrier, which holds the developer, has a rotation axis parallel to the developer carrier, and carries and agitates the developer, and a container near the passage area. In a developing device including a developer container having a slanted surface at a rear portion, a slanted surface is provided with a sheet-shaped member made of a flexible material and periodically engaged with a developer conveying member, and at a fixed position of the sheet-shaped member. The developing device is characterized in that the angle of the container wall surface with respect to the horizontal plane is larger than the angle of the slope and the angle of repose of the developer. 2. The developing device according to claim 1, wherein an angle of the inclined surface of the developer container with respect to a horizontal plane is equal to or less than a repose angle of the developer. 3. An image forming apparatus comprising the developing device according to claim 1, wherein the developing device develops the latent image bearing member to form an image. 4. A process cartridge comprising the developing device according to claim 1 and being detachable from an image forming apparatus main body.