JP2000310905A - Developing cartridge - Google Patents

Abstract

PROBLEM TO BE SOLVED: To considerably regulate the backflow of a developer housed in a developing section by the impact or vibration that the developer receives during transportation by providing a backflow preventive section with a rib-like projection suspended from a partition wall for separating the developing section of a toner drop port and a toner storage section. SOLUTION: The developing section 51 side of the toner drop port 59 is integrally formed with the rib-like projection 1 suspending toward a perpendicular direction as a backflow preventive member for preventing the backflow of the developer from the developing section 51 to the toner storage section 54 at a port wall on a developing roller 52 side of the toner drop port 59 walls. The length of this projection 1 is set at about a length at which the toner drop port 59 is concealed when viewed from the developing roller 52 side and the length at which the flowing state of the developer circulating in the developing section 52 is not disturbed. The toner drop port 59 is covered from above by such rib-like projection 1, by which the intrusion of the developer from the developing section 51 side to the toner drop port 59 is drastically lessened.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a developing cartridge provided in an image forming apparatus using an electrophotographic process.

[0002]

2. Description of the Related Art Conventionally, in an image forming apparatus using an electrophotographic process, a developing unit for supplying a toner to a photoreceptor and a toner storage unit for storing the toner to be supplied to the developing unit are integrated. Cartridges are known.

FIG. 8 is a schematic structural view of an image forming apparatus using the developing cartridge. In FIG. 8, a developing unit 51 of a developing cartridge 50 is opposed to the photoconductor at a predetermined distance, and a developing roller 52 that supplies toner to an electrostatic latent image formed on the photoconductor and performs development. And a mixing / stirring roller 53 for mixing and stirring the developer. Further, the toner storage unit 54 is disposed above the developing unit 51, and has a frame-shaped agitator 55 for stirring the stored toner and a toner storing unit 5.
1 is provided with a supply roller 56 as a carrier to be supplied to the first roller.

The developing section 51 and the toner storage section 54 are connected via a connecting section 57, and are separated and partitioned by a partition 58 at the connecting section.
Is formed with a toner drop port 59.

[0005] Other electrophotographic processes in the image forming apparatus are well-known and are not necessarily required for understanding the present invention, and therefore, description thereof will be omitted.

[0006]

By the way, the developer filled in the developing section of the developing cartridge 50 is as follows.
Unexpected shocks and vibrations during transportation of the developing cartridge,
Alternatively, toner may be stored from the developing unit due to loading methods such as horizontal, inclined, and inverted products, which should be prohibited for the handling of this type of product, and the reversing operation of the packing box during movement. Backflow of the developer may occur to the part side.

[0007] When such a backflow of the developer occurs, the amount of the developer in the developing section becomes small at the start of use immediately after installation of the apparatus, and phenomena such as white spots occur.

In order to prevent the backflow of the developer, for example, as described in JP-A-5-80653 (see FIG. 9) and JP-A-6-95506 (see FIG. 10), When the cartridge 100 is shipped or stored, the toner drop port 59 is covered with a seal member 60 from the toner storage unit 54 side to prevent the developer from flowing back. At the start of use, the seal member 60 is It has been proposed to wind up with a rotation shaft of an agitator, or to provide a retreat space 61 in the seal member 60 in the toner storage section 54 and retract from the toner drop port 59 by contraction of the elastic member 62.

However, in the above method, the seal member 60 remains wound around the shaft of the stirring roller (agitator) 55, and the rotational load of the stirring roller 55 increases.
Alternatively, the provision of the evacuation space 61 complicates the configuration inside the toner storage unit 54, and increases the size of the apparatus. Therefore, the appearance of a backflow prevention mechanism having a simple configuration without removing a member such as a sheet member is desired.

[0010]

Means for Solving the Problems The inventors of the present invention have conducted intensive studies on a backflow prevention mechanism which does not involve removal of parts such as a sheet member. As a result, a toner drop opening for dropping toner from a toner storage section to a developing section, that is, If there is a toner supply port above the developing section, if the shape of the toner drop port itself is devised, a simple structure of the backflow prevention member will not prevent the toner from dropping during use, and the flow state of the developer will be reduced. It has been found that the backflow of the developer can be prevented without disturbing.

The form of the backflow preventing member may be either a fixed state or a movable state with respect to the toner falling port. As the backflow prevention portion in the fixed state, a rib-shaped protrusion hanging from a partition separating the developing portion and the toner storage portion on the developing portion side of the toner dropping port can be exemplified. By providing the rib-shaped projections, even if the developer contained in the developing unit is likely to flow toward the toner dropping port due to shock or vibration received during transportation, the backflow of the developer can be largely controlled.

It is desirable that the rib-like projections be set as long as possible so long as they do not disturb the flow state of the developer during use. As long as it does not hinder, it can protrude in either the vertical direction or the inclined direction. The rib-shaped projection may be formed integrally or separately from the partition wall, and may be attached to the partition wall. Further, the rib-shaped projection may be disposed on either side or one side of the opening wall of the toner drop opening. It may be.

In the configuration in which the rib-shaped protrusions are arranged, the toner dropping port is open with a diameter larger than the particle diameter of the developer. Since the toner replenishing roller is in contact with the toner and inherently prevents the backflow of the developer, the rib-shaped projections and the like have technical significance as auxiliary means of the backflow prevention mechanism.

As another fixed backflow preventing member, a porous member having a small-diameter hole for allowing the passage of toner particles and preventing the passage of the developer is attached or covered so as to cover the toner drop opening. A configuration in which the mouth is closed and integrally molded with the partition wall can be exemplified. Examples of the porous member attached separately include a mesh-like member knitted by a metal net or the like and a porous plate-like member such as a punching metal. In the case of a porous member integrally formed on the partition wall, any of a form that covers only the developing section side of the toner drop port and a form that closes the toner drop port itself can be adopted.

In the case of using such a porous member, the following functions can be exhibited in addition to the function of preventing backflow. That is, in recent years, after a toner image formed on the surface of a photoconductor is transferred to recording paper, the toner remaining on the surface of the photoconductor is collected by a cleaning unit, and the collected toner is supplied again to a toner storage unit. Although an apparatus for reusing the toner is known, the reusable toner sometimes contains foreign matters such as dust and paper powder and impurities, and when these foreign substances are supplied to the developing unit together with the toner, the developing failure occurs. Cause. However, if the porous member is used, it is possible to prevent foreign matter from entering the developing unit from the toner storing unit.

Next, as a movable backflow preventing member,
One end side is fixed to one end side of the mouth wall of the toner falling port,
An example is a flexible elastic plate whose other end is pressed against the toner drop opening. The elastic plate-like body is displaceable only to the developing unit side by the pressure generated when the toner stored in the toner storage unit is supplied to the developing unit. Is released, so that the backflow of the developer can be prevented without hindering the toner replenishing operation or the toner falling from the toner storage unit side. Further, since the elastic plate-like body is arranged along the partition wall surface, the flow state of the developer circulating in the developing unit is not disturbed.

Incidentally, the developing cartridge is not only one in which the developing part and the toner storage part are integrated, but also one in which the toner collecting part is integrated when the toner collecting part is provided, as described above. You may.

[0018]

Embodiments of the present invention will be described below with reference to the drawings. In the embodiment described below, a configuration in which a backflow prevention unit is newly provided in the conventional developing cartridge shown in FIG. 8 is employed, and only the parts related to the present invention will be described. The description of the parts is omitted. Therefore, for other parts not related to the present invention, refer to the above description of the developing cartridge shown in FIG.

[First Embodiment] FIG. 1 is a sectional view of a developing cartridge according to a first embodiment. The developing cartridge according to the present embodiment includes a developing unit 51 for supplying toner to an electrostatic latent image on a photoconductor and a toner storage unit 54 for storing toner to be supplied to the developing unit 51. The developing unit 51 and the toner storage unit 54 are separated from each other by a partition 58, and a toner drop port 59 is formed in the inclined partition 58.

A backflow preventing member for preventing the developer from flowing back from the developing section 51 to the toner storage section 54 is provided on the developing section side of the toner drop port 59 as an opening wall on the developing roller 52 side of the drop port wall. In addition, a rib-shaped projection 1 hanging vertically downward is integrally formed.

The length of the projection 1 is such that the toner drop port 59 is hidden when viewed from the developing roller side.
The length is set so as not to disturb the flow state of the developer circulating inside.

On the other hand, the toner storage 5 of the toner drop port 59
A sponge-like toner replenishing roller 56 is slidably contacted on the fourth side to prevent the developer on the developing unit 51 side from flowing directly to the toner storage unit 54 side.

By covering the toner dropping port 59 from above with the rib-like projections 1, the amount of developer entering the toner dropping port 59 from the developing unit side is greatly reduced. In addition, it is possible to prevent the toner from flowing backward due to vibration or the like during transport of the developing cartridge.

The protrusion 1 is provided on the partition 5 of the developing section 51.
8 may be formed integrally or may be added as a separate part. Further, in FIG. 1, the protrusion 1 is arranged only on the opening wall of the developing roller 52 side of the opening wall of the toner falling port 59 so that the backflow of the developer can be efficiently prevented. As shown in a), a configuration may be employed in which the toner drops 59 hang down on the mouth walls on both sides.

Although the projection 1 shown in FIG. 1 has a configuration in which the projection 1 is vertically suspended from the toner drop port 59 formed on the inclined wall, the present invention is not limited to this. For example, as shown in FIG. If the horizontal partition 58 has a toner drop port 59 formed thereon, the rib-shaped projection 1 may be configured to hang down in a direction to close the toner drop port 59.

[Second Embodiment] FIG. 3 is a sectional view of a developing cartridge according to a second embodiment. In the present embodiment, the flexible elastic plate 2 is provided at the toner dropping port 59 as a backflow prevention unit.

The elastic plate 2 is an elastic sheet material made of synthetic resin, one end 2a of which is fixed to the upper side of the mouth wall of the toner drop port 59, and the other end 2b is formed of the toner drop port 5
9 so as to cover the lower wall surface. Accordingly, the elastic plate 2 can be displaced only toward the developing unit by the pressure generated when the toner stored in the toner storage unit 54 is supplied to the developing unit 51.

In the above configuration, when the toner is supplied from the toner storage unit 54 to the developing unit 51, the elastic plate 2
The toner is not deflected by the toner pressure due to the conveyance of the toner and does not hinder the toner supply. On the other hand, regarding the reverse flow of the developer from the developing unit 51 to the toner storage unit 54, the toner drop port 59
, The backflow of the developer can be prevented.

[Third Embodiment] FIG. 4 is a sectional view of a developing cartridge according to a third embodiment. The first
In the embodiments and the second embodiment, the present invention can be applied to both a case where the developer is a one-component developer composed of only a toner and a case where the developer is a two-component developer composed of a toner and a carrier. However, as long as the developer is a two-component developer, the present embodiment and the fourth embodiment described later can also prevent the developer from flowing backward.

In this embodiment, the backflow preventing member is
The mesh member 3 is attached to the developing section 51 side of the toner drop port 59 so as to cover the toner drop port 59, and allows a large number of small holes 3a (allowing passage of toner particles and blocking developer). (Mesh).

Normally, when a two-component developer is used, only the toner is supplied to the toner storage section 54, and the toner has a fine particle diameter of about 5 to 8 μm. Then, the toner supplied from the toner storage unit 54 to the developing unit becomes a developer having a particle size of about 50 to 80 μm by being mixed with the carrier. Therefore, by appropriately setting the mesh roughness (the hole diameter of the hole 3a) of the mesh member (for example, setting the mesh roughness to 10 to 40 μm), the mesh member 3 allows the passage of the toner, The structure is such that the passage of the developer is prevented.
1 can be supplied only.

As a modification of the above, instead of the mesh member 3 shown in FIG. 5A, a perforated plate member 4 shown in FIG. Can be adopted. In this case, if the diameter of the small-diameter hole 4a provided in the perforated plate member 4 is set to a size that allows the passage of the toner but prevents the passage of the developer similarly to the mesh member 3, the toner storage portion Only the supply from the developing unit 51 to the developing unit 51 can be performed, and the backflow of the developer from the developing unit 51 to the toner storage unit 54 can be prevented.

[Fourth Embodiment] FIG. 6 is a sectional view of a developing cartridge according to a fourth embodiment. In the present embodiment, instead of providing the mesh member 3 and the perforated plate member 4 as separate members as in the third embodiment, the passage of the toner to the partition 58 that separates the toner storage portion 54 and the developing portion 51 is performed. Is allowed, but the porous portion 5 formed with a large number of small-diameter holes 5a large enough to block the passage of the developer is directly integrally molded. Similar effects can be obtained.

In this case, although the toner drop port 59 does not exist, it can be regarded as substantially formed integrally with the partition wall 58 so that the porous portion 5 closes the toner drop port 59.

As described above, in any of the first to fourth embodiments, an unexpected impact or vibration received by the developing cartridge during transportation or a horizontal product of a product which should be prohibited. With a simple configuration, it is possible to prevent the developer from flowing backward from the developing unit side to the toner storage unit side due to a loading method such as an inclined product, a reverse product, or a reversing operation of a moving packing box. Further, the toner supply operation from the toner storage unit 54 side and the toner fall are not interrupted.
Since the developer backflow prevention unit is disposed at the toner drop port located above the developing unit 51, the flow state of the developer circulating in the developing unit is not disturbed.

Therefore, by adopting such a configuration, various restrictions associated with packing, loading, moving, etc. of the developing cartridge are relaxed, which leads to improvement in production efficiency, work efficiency, and the like.

Further, in particular, the third embodiment and the fourth embodiment
If the configuration in which the mesh member 3, the perforated plate member 4, and the perforated portion 5 are provided at the toner drop opening of the partition wall 58 is adopted in the image forming apparatus of the type described in Also, there is an advantage that foreign matter can be prevented from entering the developing unit 51 from the toner storage unit 54. In this case, the toner collecting section may be integrated with the toner storing section as a component of the developing cartridge, or may be provided separately.

[0038]

As is apparent from the above description, according to the present invention, a backflow preventing member having a simple structure is provided on the developing section side of the toner dropping port of the partition between the toner storing section and the developing section of the developing cartridge. It is caused by unexpected shock or vibration received by the developing cartridge during transportation, or by a loading method such as a horizontal product, a tilt product, or a reversal product of a product that should be prohibited, or a reversal operation of a moving packing box. Backflow of the developer from the developing section to the toner storage section can be prevented.

[Brief description of the drawings]

FIG. 1 is a sectional view of a developing cartridge according to a first embodiment of the present invention.

FIGS. 2A and 2B are cross-sectional views showing different forms of projections, respectively.

FIG. 3 is a cross-sectional view of a developing cartridge according to a second embodiment.

FIG. 4 is a cross-sectional view of a developing cartridge according to a third embodiment.

FIG. 5 (a) is a view showing a mesh member covering a falling port.
(B) is a plan view showing a perforated plate portion replacing the mesh member.

FIG. 6 is a sectional view of a developing cartridge according to a fourth embodiment.

FIG. 7 is a view taken in the direction of arrow B in FIG. 6;

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

FIG. 9 is a cross-sectional view of a developing cartridge provided with a drop port sealing member according to a first conventional example.

FIG. 10 is a cross-sectional view of a developing cartridge provided with a drop-seal member according to a second conventional example.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Rib-shaped protrusion 2 Elastic plate-shaped body 3 Mesh member 4 Perforated plate member 5 Porous part 51 Developing part 54 Toner storage part 56 Supply roller 58 Partition wall 59 Toner drop port

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Yasuyuki Ishiguro 22-22, Nagaikecho, Abeno-ku, Osaka-shi, Japan Inside Sharp Corporation (72) Inventor Hiroshi Tanizawa 22-22, Nagaikecho, Abeno-ku, Osaka-shi, Osaka Incorporated (72) Inventor Tsutomu Nagata 22-22 Nagaikecho, Abeno-ku, Osaka City, Osaka Sharp Corporation (72) Inventor Yoshinori Otsuka 22-22 Nagaikecho, Abeno-ku, Osaka City, Osaka Sharp Corporation F Terms (reference) 2H077 AA12 AA15 AA18 AA27 BA08 BA09 CA11 FA22 GA04

Claims (7)

[Claims] A developing unit for supplying toner to an electrostatic latent image on a photoreceptor; and a toner storage unit for storing toner supplied to the developing unit, wherein the developing unit and the toner A developing cartridge in which a toner drop port for dropping toner from the toner storing section side to the developing section side is formed in a partition separating the storing section from the toner storing section side. In order to prevent the developer from flowing back from the developing unit to the toner storage unit due to the product, the inclined product, and the reversing operation, the toner is provided in a fixed state on the developing unit side of the toner dropping port, and the toner in use is used. A backflow preventing member disposed so as not to hinder the falling of the developer and not to disturb the flow state of the developer. 2. The developing cartridge according to claim 1, wherein said backflow prevention member is a rib-shaped projection hanging down from said partition at a developing portion side of said toner drop opening. 3. The mesh-like member having a small-diameter hole, wherein the backflow preventing member is attached so as to cover the toner drop opening from a developing unit side, and allows the passage of toner particles and prevents the passage of the developer. The developing cartridge according to claim 1, wherein 4. The backflow prevention member is attached so as to cover the toner drop opening from a developing unit side, and is formed of a perforated plate having a small-diameter hole for allowing passage of toner particles and preventing passage of developer. The developing cartridge according to claim 1. 5. A porous portion, wherein said backflow prevention member has a small-diameter hole for allowing passage of toner particles and preventing passage of developer, and is integrally formed with said partition so as to close said toner drop opening. 2. The developing cartridge according to claim 1, comprising: 6. A developing unit for supplying toner to an electrostatic latent image on a photoreceptor, and a toner storage unit for storing toner to be supplied to the developing unit are integrated with each other. A developing cartridge in which a toner drop port for dropping toner from the toner storing section side to the developing section side is formed in a partition separating the storing section from the toner storing section side. To prevent the developer from flowing back from the developing unit to the toner storage unit due to the product, the tilt product, and the reversing operation, the toner is provided movably on the developing unit side of the toner drop port, and the toner is used during use. A backflow preventing member arranged so as not to hinder the falling of the developer and not to disturb the flow state of the developer. 7. The backflow prevention member is formed of a flexible elastic plate member having one end fixed to one end of the mouth wall of the toner drop opening and the other end pressed against the toner drop opening.
7. The developing cartridge according to claim 6, wherein the elastic plate-shaped member is displaceable only toward the developing unit by a pressure generated when the toner stored in the toner storage unit is supplied to the developing unit.