JP2000147904A - Developing apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent toner, carrier, and developer from entering the rotary member of a developing device and scattering out of the developing device and to prevent the toner and so on entering the rotary member of the developing device from melting from frictional heat and fixing firmly and locking the rotary member. SOLUTION: A developing device is provided in its bearing housing 103 with a toner discharge port 104 for discharging toner entering a bearing member 100 from a sealing member and is further provided with a brush-like sweeping member 105. By the easy discharge of toner entering the bearing housing 103, nonconformities such as causing toner to scatter out of the developing device or to fix firmly and lock a rotary member 4 can be prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrophotographic developing apparatus using a dry toner, such as a copying machine or a printer, and more particularly to a means for preventing toner or the like from entering a rotating member holding bearing member. And a developing device.

[0002]

2. Description of the Related Art In an electrophotographic image forming apparatus such as a copying machine, a printer, a facsimile, etc., a developing device is made by attaching a toner containing a pigment or a one-component developer made of magnetic or non-magnetic toner and the toner to the surface. A two-component developer using a magnetic carrier to be conveyed is used. Generally, a developing device using a two-component developer has a cylindrical developing sleeve rotatably supported with a magnet roll composed of a magnet body having a plurality of magnetic poles inside, and toner is adhered to the surface of the developing sleeve. The magnetic carrier is held, transported to a development area, and the electrostatic latent image on the opposite electrostatic latent image carrier is developed with toner to form a visualized image. Each time development is performed, the toner is gradually consumed and the amount of toner in the developing device decreases, so that the toner is appropriately replenished from the toner storage device and mixed with and agitated with the carrier in the developing device to prepare for new development. ing. Generally, the average particle size is
A developer comprising a magnetic carrier of 0 to 100 μm and a non-magnetic toner having an average particle size of about 10 μm is used.
Due to the recent demand for improvement in image quality, the average particle size of the carrier and the toner tends to be gradually reduced.

A rotating member such as a transport paddle and a stirring roller, a bearing member for supporting the end of the rotating shaft, a transport paddle and a stirring roller for uniformly mixing and transporting the developer are housed in the developing device. I have. An appropriate gap (rotation gap) is provided between the shaft diameter of the rotation member and the inside diameter of the bearing so that the stored rotation member rotates smoothly and the backlash of the shaft does not become too large. However, since the rotation is performed in the presence of minute powder such as toner and carrier, the powder such as carrier easily enters the rotation gap. Since the core component of the carrier is iron powder or ferrite and has high hardness, it plays the role of an abrasive in the rotating gap, and the diameter of the rotating member is reduced, or conversely, the inner diameter of the bearing is increased and rattling of rotation is caused. Problems such as an increase in size occur.

On the other hand, if the toner enters the rotation gap, the toner may be scattered outside the developing device through the bearing portion,
In the rotating member, an acrylic resin or the like, which is a main component of the toner, is melted and fixed, and the rotating torque of the rotating member is increased (torque up), and the load of the driving source is overloaded, or in the worst case, Problems such as the rotation of the rotating member being blocked (roller lock) occur. If these problems are neglected and proceed, the rotation of the rotating member may be stopped or the recording apparatus may not be operable. For the above reasons,
A structure that prevents powder from entering the rotation gap is required. As a technique for preventing such a toner or a developer from entering a portion other than a predetermined portion, a rotating shaft end of a rotating member (here, referred to as a transport paddle 4 or a stirring roller 5) provided in a developing device is used. A sealing member 17 such as a V-ring 17a shown in FIG. 8A or a G-seal 17b shown in FIG. 8B is provided between the bearing member 20 that supports the portions 4a and 5a and the rotating members 4 and 5.
Is provided to prevent toner and developer contained in the developing device from entering the internal space ＠ of the bearing member 20.

[0005]

However, in such a developing device, toner and the like gradually enter the internal space even if the seal member 17 is functioning normally. In the case of the above-described conventional V-ring, since the surface of the retainer 102 is not completely smooth and has microscopic irregularities, it is impossible to prevent toner from entering. In the case of the G-seal, the rotating shaft is not completely rotated only on the spot, but is also rotated eccentrically to a considerable degree microscopically, and the contact and separation between the G-seal and the rotating shaft are periodically repeated. Therefore, if the toner or the like has been used for a long time in a state where the toner or the like has entered the space generated at the time of separation, the toner or the like finally reaches the internal space.
As described above, the rotating member is polished by filling the internal space with the carrier, and the internal pressure is increased by filling with the toner, the toner is scattered outside the developing device, and the temperature is increased by the frictional heat. It is difficult to prevent problems such as the toner being dissolved and fixed to lock the rotating member and the like.

Accordingly, the present invention has been made in view of the above-described problems, and has as its object to allow toner, carrier and developer to enter a rotating member of a developing device and scatter outside the developing device. Another object of the present invention is to provide a developing device that prevents the toner and the like that have entered a rotating member of the developing device from melting due to frictional heat, thereby fixing the rotating member and preventing the rotating member from being locked. In addition, bearing by carrier,
An object of the present invention is to provide a developing device that prevents the rotation shaft from being polished and rattling.

[0007]

According to a first aspect of the present invention, there is provided an image forming apparatus, comprising: a bearing member for supporting a rotating shaft end of a rotating member provided in a developing device; In the developing device, a seal member is provided between the rotating member to prevent toner and developer contained in the developing device from entering the bearing portion of the bearing member. This is a developing device provided with a toner discharge port for discharging toner to be formed in a bearing housing. According to a second aspect of the present invention, in the developing device according to the first aspect, a sweeping member that sweeps out toner entering the bearing member from the seal member is provided on a rotating member facing the toner discharge port. is there. According to a third aspect of the present invention, in the developing device according to the first aspect, a sweeping member that sweeps out toner entering the bearing member from the seal member is provided on an inner wall of the bearing housing except for a portion of the toner outlet. Developing device. According to a fourth aspect of the present invention, there is provided the developing device according to the first aspect, further comprising a second seal member between the toner outlet and the bearing. According to a fifth aspect of the present invention, there is provided the developing device according to any one of the first to fourth aspects, further comprising a passage for guiding the toner from the toner discharge port of the bearing member to the outside through the inside of the developing device side plate. is there. According to a sixth aspect of the present invention, there is provided the developing device according to any one of the first to fourth aspects, further comprising a container for storing the toner discharged from the toner discharge port of the bearing member inside the developing device. It is.

An image forming apparatus using the developing device of the present invention includes a copying machine for creating a copy of a document, a printer for creating an image by visualizing records in an information recording medium, and a printer for visualizing transmitted information to create an image. It includes a device such as a facsimile to be created. If the developing device is an electrophotographic type, the latent image forming means may be used in any of a so-called digital type or analog type image forming apparatus. The developer used in the developing device may be any of a two-component developer using a carrier and a toner, a one-component developer containing a magnetic material, and a non-magnetic one-component developer containing no magnetic material. It may be.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS (1) Invention of Claim 1 An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 shows a small-diameter 2 using a two-component developer in which the present invention is implemented.
FIG. 2 is a schematic view illustrating a configuration of a step sleeve type developing device.
In FIG. 1, the developer in the developing device 1 is supplied to the first sleeve 2 by the transport paddle 4. This first sleeve 2
The developer supplied to the photosensitive drum 15 is formed into a thin layer having a constant thickness by the doctor blade 7, and is rotated by the first sleeve 2 and the second sleeve 3 in the forward direction with respect to the photosensitive drum 15. The electrostatic latent image formed on the photosensitive drum 15 is conveyed to the surface of the drum 15 and is visualized (developed). Here, the developer that does not contribute to the development is again transferred to the developing device 1 by the transport paddle 4 and the stirring roller 5.
It is conveyed into and stirred. On the other hand, the surplus developer regulated to be unloaded to the photosensitive drum 15 by the doctor blade 7 is sent to the separator 6 and the transport screw 8 and is laterally stirred. In addition, new toner sent by the agitator 9 is supplied to the developer after the development. The new toner is laterally stirred by the stirring roller 5, mixed with the developer, and supplied to the transport paddle 4 together with the surplus developer returned by the separator 6.

The toner concentration of the developer in the developing device 1 is determined by detecting the amount of toner adhered to the image pattern for detecting the toner concentration formed on the photosensitive drum 15 by the optical sensor 16, and the detection result of the optical sensor 16. Is determined by a controller (not shown) based on Here, when it is determined that the toner concentration in the developing device 1 is lower than the reference value, the toner supply motor (not shown) is driven to
4 is supplied to the toner hopper 12 from the toner transport paddle 13 and the second agitator 1.
The toner is supplied into the developing device 1 by the toner supply roller 11 via the toner supply roller 0. This toner supply operation is stopped when the toner density in the developing device 1 reaches the reference value.

FIG. 2 is a schematic sectional view showing the structure of a bearing portion of the developing device according to one embodiment of the present invention. A rotating member (here, the transport paddle 4,
However, the same applies to the stirring roller 5. ) Is a molded product made of resin, and has a rotating shaft 4a such as a stainless steel bar or a chemical nickel-plated steel bar at both ends in consideration of wear resistance.
Is press-fitted. The transport paddle 4 is inserted into the developing device side plate 19, and both ends are supported by a bearing member 100 held so as not to rotate. The end of the rotating shaft 4a is a bearing 101
The other end of the rotating shaft 4a is driven by being connected to a main motor of an image forming apparatus (not shown) by a gear or a chain. A V-ring 17a is disposed as a seal member 17 at the end of the rotating shaft 4a. The V-ring 17a is made of an elastic rubber material such as nitrile, acrylic, silicon, fluorine and the like. The V-ring 17a rotates together with the transport paddle 4. Here, a G seal 17b can be arranged as a seal member in addition to the V ring 17a. The G seal 17b is made of a rubber material such as urethane rubber or silicone rubber, or a thermoplastic resin material such as polyethylene. In addition, you may seal with a sponge and urethane foam. The bearing member 100 is provided in a bearing housing 103 and includes a bearing 101 and a retainer 102.

The bearing housing 103 is a member for holding the bearing 101 and the retainer 102. The bearing 101 is press-fitted into a bearing housing 103. The bearing housing 103 is made of a resin material such as polystyrene or polycarbonate from the viewpoint of cost. This is because it is cost-effective. When heat dissipation is important, die casting of a metal such as aluminum or zinc can be used. In addition, when the bearing is used in a portion where the load is low, polyacetal or the like may be used as a bearing material and integrated with the bearing 101. The bearing 101 supports the load of the rotating shaft 4a and smoothly transmits the drive. When a ball bearing is used, a sealed type is more preferable than an open type, and a contact rubber sheet type is more preferable in order to prevent toner from entering. Although a ball bearing is used in this embodiment, a sliding bearing may be used in a portion where the load is low. The retainer 102 is on the surface of the bearing housing 103 and firmly contacts the seal member 17 to prevent toner from entering the internal space ＠. A metal material having excellent surface smoothness and high hardness, such as stainless steel or brass, is used.

In addition, as a stirring roller 5 in the developing device 1, a spiral body is screwed into a spiral groove formed on the rotating shaft 5a, and the spiral groove is subjected to soldering or bonding with an elastic adhesive, and is rotated with the spiral body. The shaft 5a is fixed. The stirring roller 5 is rotated by being driven by a drive transmission gear provided outside the developing device 1,
The toner is being agitated. The transport paddle 4 similarly fixes a water wheel type blade to the rotating shaft 4a. However, the stirring roller 5 and the transport paddle 4 of the present invention are not limited to these.

The toner outlet 104 is provided in the bearing housing 103 of the bearing member 100. Toner outlet 1
Numeral 04 designates a rectangular or circular hole in the bearing housing 103 for allowing the discharged toner to fall naturally. As described above, in the developing device 1, in the long-term use, the toner enters the internal space か ら from the seal member 17, but falls down through the toner outlet 104, so that the internal space さ れ is filled with the toner and the internal pressure increases. Dispersion outside the developing device, dissolution of toner due to temperature rise,
Problems such as sticking and locking can be prevented. The toner outlet 104 is desirably provided at the lower portion of the bearing housing 103 in order to promote the discharge of the toner and to prevent toner and developer from entering therethrough.

(2) Claim 2 FIG. 3 is a schematic sectional view showing the structure of a bearing portion of a developing device according to an embodiment of the present invention. Claim 1
Similarly, the toner outlet 104 is provided at the lower part of the bearing housing 103. Further, a sweeping member 105 is provided at a portion around the transport paddle rotating shaft 4a facing the toner discharge port 104. The sweeping member 105 is formed of a bristle brush, a sweeping member base, and an adhesive for bonding the sweeping member 105 to a rotating shaft.
The bristle brush may be any of metal fibers such as stainless steel and copper, fibers such as non-metal or metal oxide such as carbon and glass fiber, resin fibers such as polyester and polypropylene, and animal fibers. Metal and non-metallic fibers are preferred because they have high strength and high strength. It is preferable that the length of the bristle brush is longer than the distance from the rotating shaft 4a to the bearing housing 103. This is because the toner attached to the bristle brush is easily discharged from the toner discharge port 104. As the material of the sweeping member base, it is preferable to use elasticity such as a resin film of polyethylene terephthalate (PET) or polyethylene (PE) rubber because it is easy to wind around the rotating shaft 4a. According to the developing device, as described above, the toner that gradually enters the internal space か ら from the seal member 17 during the long-term use is positively discharged by the discharge member 105. This allows
Since the internal space ＠ is filled with the toner, the toner generated due to the temperature rise due to the frictional heat of the rotating member melts and adheres,
Problems such as locking can be more stably prevented.

(3) Invention of Claim 3 FIG. 4 is a schematic sectional view showing the configuration of a bearing of a developing device according to an embodiment of the invention described in claim 3. Claim 1
The toner outlet 104 is provided in the lower part of the bearing housing 103 similarly to the invention described in (1). Further, a sweeping member 105 is provided at a portion around the inner wall of the bearing housing 103 facing the transport paddle rotation shaft 4a. The configuration of the sweeping member 105 is as described above. As a result, the toner gradually entering the internal space ＠ from the seal member 17 is positively swept out by the sweeping member 105. In particular,
The toner that has entered the internal space 間 の between the rotating members is in a molten state in the internal space で due to frictional heat between the rotating members, and a part of the toner adheres to the rotating shaft 4a. This toner can collide with a bristle brush rotating at high speed, adhere to the tip of the bristle brush that is longer than the rotating shaft 4a, and can be sequentially sent to the toner outlet 104 and discharged.

(4) Invention of Claim 4 FIG. 5 is a schematic sectional view showing the structure of a bearing portion of a developing device according to an embodiment of the present invention. In this developing device, the toner outlet 104 is provided below the bearing member 100 as in the first embodiment. Further, a second seal member 106 is provided between the toner outlet 105 and the bearing member 100 in the bearing member 100. As the second seal member 106, a G seal,
A sealing member such as a V-ring can be used. Since the developer in the developing device 1 is mixed and stirred by the stirring roller 5 and the like, the developer moves violently under a large pressure in the developing device 1. For this reason, the V ring 1
Similarly, the developer is pressed against the nozzle 7a with a large pressure, and the toner and the developer are pushed into a small space between the V ring 17a and the rotating shaft 4a. Then, in long-term use, the internal space ＠
The toner and the developer intrude into the toner. However, in the internal space ＠, even if toner and developer exist,
Is not pressed against the sealing member 106. Therefore, it is possible to completely prevent the toner and the developer from intruding into the next bearing 101, and further, since the toner and the developer fall to the lower part through the toner discharge port 104, the inner space ＠ is not filled with the toner.

(5) Invention of Claim 5 FIG. 6 is a schematic sectional view showing the structure of a bearing portion of a developing device according to an embodiment of the invention described in claim 5. Claim 1
The toner outlet 104 is provided in the lower part of the bearing member 100 similarly to the invention described in (1). Further, a toner discharge passage 107 is provided from the toner discharge port 104 to pass through the inside of the developing device side plate 19 and communicate with the outside of the developing device 1.
Further, a toner storage container 109 for storing toner discharged under the toner discharge passage 107 can be provided. Since the developer in the developing device 1 is mixed and stirred by the stirring roller 5 and the like, the developer moves violently under a large pressure in the developing device 1. For this reason, there is a possibility that the developer flows backward from the toner discharge port 104 and enters the internal space 侵入. Further, the toner to be discharged may not be discharged from the toner discharge port 104 in some cases. Therefore, the toner discharge passage 107
Thereby, it is possible to easily discharge the toner entering the internal space ＠. In addition, contamination in the image forming apparatus can be prevented by the toner container 109 that stores the discharged toner. The toner container 109 does not need to be strong because it does not rotate, and may be easily removable when it is filled with toner.

(6) Invention of Claim 6 FIG. 7 is a schematic sectional view showing the structure of a bearing portion of a developing device according to an embodiment of the present invention. Claim 1
The toner outlet 104 is provided in the lower part of the bearing member 100 similarly to the invention described in (1). Further, a toner container 109 is provided in the developing device 1 below the toner discharge port 104 in order to prevent the developer from entering the developing device 1 and facilitate the discharge of the toner. Further, an enclosing member 110 of an elastic member such as a malt plane may be provided in order to prevent a space from being formed between the toner storage container 109 and the developing device side plate 19.

[0020]

As described above, in the developing device according to the first aspect, the bearing member is provided with the toner discharge port, so that the toner that has entered the internal space from the seal member passes through the toner discharge port and goes to the lower portion. It can be dropped and discharged. In the developing device according to the second aspect, a sweeping member is provided at a portion of the rotating shaft facing the toner outlet, and the toner that has entered the internal space from the seal member is actively swept by the sweeping member. . In the developing device according to claim 3, since the sweeping member is provided on the inner wall of the bearing member facing the rotating shaft, the sweeping member removes the toner that enters the internal space from the sealing member and adheres strongly to the rotating shaft. Can be positively discharged. In the developing device according to the fourth aspect, since the second seal member is provided between the toner discharge port in the bearing member and the bearing, the second seal member is provided between the first seal member and the bearing of the toner that enters the internal space. Intrusion can be completely blocked, and the toner can be dropped and discharged through the toner discharge port. Further, with the above configuration, the internal pressure is increased by filling the internal space with the toner, and the toner is scattered outside the developing device, and the toner is more stably dissolved, fixed, and locked due to a rise in temperature. Can be prevented.

In the developing device according to the fifth aspect, since the toner discharging passage for discharging the toner is provided in the developing device side plate, the toner can be discharged to the outside of the developing device.
In the developing device according to the sixth aspect, since the toner discharge container is provided inside the developing device, the toner entering the internal space can be easily stored by being dropped to the lower part through the toner discharge port. As a result, it is possible to prevent the developer and the toner from flowing back into the internal space through the toner outlet.

[Brief description of the drawings]

FIG. 1 is a schematic view showing the configuration of a small-diameter two-stage sleeve type developing device using a two-component developer in which the present invention is implemented.

FIG. 2 is a schematic sectional view showing a configuration of a bearing portion of the developing device according to the first embodiment of the present invention;

FIG. 3 is a schematic sectional view showing a configuration of a bearing portion of the developing device according to an embodiment of the present invention.

FIG. 4 is a schematic sectional view showing a configuration of a bearing portion of the developing device according to an embodiment of the present invention.

FIG. 5 is a schematic cross-sectional view showing a configuration of a bearing portion of the developing device according to an embodiment of the present invention.

FIG. 6 is a schematic sectional view showing a configuration of a bearing of the developing device according to an embodiment of the invention described in claim 5;

FIG. 7 is a schematic sectional view showing a configuration of a bearing portion of the developing device according to an embodiment of the present invention.

FIG. 8A is a schematic cross-sectional view showing a developing device using a conventional V-ring. (B) shows G of the prior art.
FIG. 3 is a schematic sectional view showing a developing device using a seal.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Developing device 2 1st sleeve 3 2nd sleeve 4 Conveying paddle 4a Conveying paddle rotating shaft 5 Stirring roller 5a Stirring roller rotating shaft 6 Separator 7 Doctor blade 8 Conveying screw 9 1st agitator 10 2nd agitator 11 Toner supply roller 12 Toner hopper DESCRIPTION OF SYMBOLS 13 Toner conveyance paddle 14 Toner bottle 15 Photoconductor drum 16 Optical sensor 17 106 Seal member 17a V ring 17b G seal 19 Developing device side plate 20 Bearing member 21 E-ring 100 Bearing member 101 Bearing 102 Retainer 103 Bearing housing 104 Toner discharge port 105 Cleaning Outgoing member 107 Toner discharge passage 108 109
Toner container 110 Enclosure 部 材 Internal space

Claims (6)

[Claims] 1. A bearing member for toner and developer housed in a developing device, between a bearing member rotatably supporting an end of a rotating shaft of a rotating member provided in the developing device and the rotating member. A developing device provided with a seal member for preventing intrusion into the bearing portion of the developing device, characterized in that the bearing housing is provided with a toner discharge port for discharging toner entering the bearing member from the seal member. 2. The developing device according to claim 1, wherein a sweeping member that sweeps out toner entering the bearing member from the seal member is provided on the rotating member facing the toner discharge port. . 3. The developing device according to claim 1, further comprising a sweeping member that sweeps out toner entering the bearing member from the seal member on an inner wall of the bearing housing except for a toner discharge port. Developing device. 4. The developing device according to claim 1, further comprising a second seal member between the toner outlet and the bearing. 5. The developing device according to claim 1, further comprising a passage for guiding toner from the toner discharge port of the bearing member to the outside through the inside of the developing device side plate. . 6. The developing device according to claim 1, further comprising a container for storing toner discharged from a toner discharge port of a bearing member inside the developing device. apparatus.