JP2006058371A - Developing device, imaging unit having the developing device, and image forming apparatus having the unit - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a developing device designed to reduce image defects and toner soil inside the device by preventing toner from circulation on the surface of developer, and reducing toner scatter from a toner supply port, and to provide an imaging unit having the developing device and an image forming apparatus having the imaging unit. <P>SOLUTION: The developing device includes: developer 1, a stirring member 2, a developer carrier 12, a developer regulating member 14, and a housing 3 in which they are housed or to which they are attached. In the developing device, an opening 3b for connecting the leading end 5a of a toner supply device having a toner supply mechanism 6 is disposed in the external wall of the housing case 3 so as to be lower than the rotation center height of the stirring member 2. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a developing device that requires powder supply in an image forming apparatus that uses an electrophotographic process such as a copying machine, a facsimile machine, and a printer, an image forming apparatus including the same, and an image forming apparatus including the developing device. .

In a developing device used in an electrophotographic image forming apparatus, an agitating member is disposed in a developing container and rotated to agitate and convey the developer, and supply the developer to a developing roller disposed opposite to the photosensitive member. Like to do. Further, a new developer is supplied into the container from a toner replenishing section provided in the developing container.
In the prior art, it is known that when a stirring member is covered with a developer near the toner replenishing portion, the supplied toner floats on the surface of the developer and circulates without stirring (for example, patents). Reference 1).
Further, in the conventional toner replenishing device, there is a case where the toner is oversupplied by erroneously detecting that the density sensor that detects the developer concentration by the change of magnetic flux detects that the toner amount is small.
Furthermore, if toner that is not sufficiently electrically connected to the carrier is supplied to the developing unit (opposite the photoconductor), toner scattering may occur, causing abnormal images and toner contamination in the image forming apparatus. is there.
Japanese Patent Laid-Open No. 10-142916

Further, in the conventional technique, toner contamination inside and outside the image forming apparatus also occurs due to toner scattering from the toner supply port.
Accordingly, an object of the present invention is to develop in which the toner does not circulate on the surface of the developer in consideration of the above-described situation, and toner scattering from the toner supply port is reduced, thereby reducing image abnormality and internal toner contamination. An apparatus, an image forming apparatus including the same, and an image forming apparatus including the same.

In order to solve the above-described problems, the invention described in claim 1 includes a housing case that houses a developer, and a stirring member that is rotatably supported in the housing case and stirs and conveys the developer. The developing device is characterized in that an opening for connecting the tip of the toner supply device is provided below the rotation center height of the stirring member on the outer wall of the housing case.
The invention of claim 2 is characterized in that in claim 1, a backflow prevention valve for opening and closing the opening is provided.
According to a third aspect of the present invention, in the second aspect, an elastic body that urges the backflow prevention valve in a closing direction is disposed between the backflow prevention valve and a part of the housing case.
According to a fourth aspect of the present invention, there is provided the developing device according to the second aspect, wherein a permanent magnet is disposed in the vicinity of the opening.
According to a fifth aspect of the present invention, the developing device according to the fourth aspect is characterized in that the backflow prevention valve is a magnetic material.
According to a sixth aspect of the invention, the developing device according to the third aspect is characterized in that the elastic body is a magnetic body.
According to a seventh aspect of the present invention, an air outlet is provided between the tip of the toner supply device and the backflow prevention valve, an air inlet is provided on the upper surface of the stirring chamber, and a blower mechanism is provided between the air outlet and the air inlet. A developing device according to any one of claims 1 to 6, wherein the developing device is provided.
According to an eighth aspect of the present invention, there is provided an image forming unit including the developing device according to any one of the first to seventh aspects.
According to a ninth aspect of the invention, there is provided an image forming apparatus including the developing device according to any one of the first to seventh aspects.
According to a tenth aspect of the present invention, there is provided an image forming apparatus including the image forming unit according to the eighth aspect.

According to the present invention, since the opening of the toner supply device is hidden by the developer, the toner is supplied into the developer, and the toner is prevented from circulating on the developer, thereby causing an abnormal image due to toner scattering or the like. To prevent.
According to the present invention, when the bulk of the developer is higher than the rotation center of the stirring member, by preventing the supplied toner from flowing over the developer, an image abnormality due to toner scattering from the developing device, Toner contamination inside and outside the image forming apparatus can be reduced.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 is a schematic sectional view showing the configuration of an embodiment of a developing device according to the present invention. In FIG. 1, a developer 1 is accommodated in a housing case 3 forming a developing device housing, and a stirring member 2 is rotatably supported.
On the outer wall of the housing case 3 below the rotation center of the stirring member 2, an opening 3b for connecting the tip 5 of the coiled toner supply device is provided. An operation is performed in which toner is supplied from the tip 5 of the toner supply device into the developer 1. In the figure, reference numeral 4 indicates the rotation direction of the stirring member, and reference numeral 7 indicates the rotation direction of the toner supply mechanism.
In FIG. 1, another stirring member 2 ′ is rotatably arranged adjacent to the stirring member 2, and a developer carrier (developing roller) 12 is disposed obliquely above the stirring member 2 ′. A developer regulating portion 14 is disposed immediately above the developer carrier 12, and a latent image carrier (photosensitive drum) 13 is disposed obliquely above the developer carrier 12.
The depth of the housing case 3 was about twice the outer diameter of the agitating member 2 and was an inverted dome shape. Developer 1 was added up to about 2/3 of the stirring member 2 on average. As the stirring member 2, a spiral screw was used.
On the outer wall of the housing case 3, an opening 3 b for connecting the tip 5 of the toner supply device is provided so that the center comes to a position 45 degrees obliquely below the rotation center of the stirring member 2. A part of the opening was prevented from protruding above the rotation center of the stirring member 2.
Usually, the bulk of the developer 1 at the toner supply site varies depending on the rotational speed and conveying ability of the stirring member 2 and the installation angle of the image forming apparatus. In this embodiment, with the stirring member 2 rotated, the installation angle of the image forming apparatus is tilted so that the developer height is such that the stirring member 2 is hidden.
The tip 5 of the toner supply device is a cylindrical tube, and a helical coil-shaped toner supply mechanism 6 is provided inside the tube. By rotating the toner supply mechanism 6, the toner is pushed into the developer 1 and supplied.

FIG. 2 is a schematic cross-sectional view showing a first embodiment of a portion A surrounded by a schematic square in FIG. In FIG. 2, a retractable backflow prevention valve 8 is provided in the opening 3 b of the housing case 3. The backflow prevention valve 8 swings around a fulcrum 9 provided in the casing to open and close the opening 3b.
When the toner supply device tip 5 is connected to the developing device, the toner supply device tip 5 hits the backflow prevention valve 8 and moves toward the stirring member 2. When the toner supply device tip 5 is separated from the developing device, the toner supply device tip 5 is separated from the backflow prevention valve 8, and the backflow prevention valve 8 is closed by the pressure of the developer 1.
In the present invention, when the toner is supplied, the opening of the toner supply device enters the developer, so that the toner is supplied into the developer and the toner is prevented from circulating on the surface of the developer. Prevents abnormal images caused by scattering.
The retractable backflow prevention valve 8 covering the opening hole is formed with a hole through which a shaft passes through a convex portion provided on the upper side behind the opening 3b of the housing case 3, and this hole provided in the housing 3 and the backflow prevention valve 8 are provided. The back-flow prevention valve 8 was pivotally supported by the fulcrum 9 so as to be freely opened and closed.
The developing device is configured to be able to advance and retract in the direction of the arrow with respect to the photosensitive drum 13 by a driving mechanism (not shown), and during development (during driving), the developing device is displaced toward the photosensitive member side to bring the developing roller 12 close to the photosensitive drum. During non-development, it moves away from the photoreceptor and moves away. The moving direction of the developing device is parallel to the attaching / detaching direction of the tip 5 of the toner supply device.
When the developing device is in the driving position, the front end 5 of the toner supply device hits the backflow prevention valve 8, and the backflow prevention valve 8 floats and opens to the agitating member 2 so that the toner enters the casing. When the developing device is removed, the tip 5 of the toner supply device is separated from the backflow prevention valve 8, and the backflow prevention valve 8 is closed by the pressure of the developer 1 to block the developer 1 from leaking into the housing case 3.
Alternatively, the backflow prevention valve may be opened and closed by fixing the developing device and configuring the front end 5 of the toner supply device so that it can be inserted into and removed from the opening 3a (movable forward and backward).

FIG. 3 is a schematic sectional view showing a modification of the first embodiment of FIG. In FIG. 3, a recess is provided in the backflow prevention valve 8 and the housing case 3, and an elastic body 10 is inserted into the recess and sandwiched. That is, the protrusion 3A is provided on the inner wall of the case 3, and the backflow prevention valve 8 is urged in the closing direction by the other end of the elastic body 10 having one end supported by the protrusion 3A.
With this configuration, when the tip 5 of the toner supply device is separated from the backflow prevention valve 8, the elastic body 10 returns to its original state, and the opposite side of the backflow prevention valve to the fulcrum also contacts the inner wall of the housing case 3. Performs the action of closing.
When the tip 5 of the toner supply device is connected to the developing device, the backflow prevention valve 8 is pushed by the toner supply device, the backflow prevention valve 8 is tilted, and the connection portion is opened. When the front end 5 of the toner supply device is separated from the developing device, the backflow prevention valve 8 closes the opening by the developer pressure due to the developer's own weight and prevents the developer from flowing out.
As the elastic body 10, for example, a metal spring of φ3 mm is used. A hole equivalent to the spring wire diameter is made at a suitable position of the check valve 8. The housing case 3 is also provided with a convex portion, and a hole equivalent to the spring wire diameter is formed in the surface corresponding to the backflow prevention valve 8 and the spring is set in both the holes. When the front end 5 of the toner supply device is separated from the backflow prevention valve 8, the backflow prevention valve 8 is closed by a repulsive force that returns the elastic body 10.

FIG. 4 is a schematic cross-sectional view showing a second embodiment of a portion A surrounded by a schematic square in FIG. A rib 3a stands outside the opening 3b of the housing case 3 and the inner diameter of the circular annular permanent magnet 11 is disposed on the outer periphery of the opening 3b.
When the developing device is separated from the front end 5 of the toner supply device, an operation of closing the opening 3b of the housing case 3 with the developer regulated by the magnetic force from the permanent magnet 11 is performed. At the same time, since the backflow prevention valve 8 made of a magnetic material is attracted by the permanent magnet 11 outside the opening, the suppressing force of the backflow prevention valve 8 is improved.
When the tip 5 of the toner supply device is connected to the developing device, the developer regulated by the permanent magnet 11 is pushed by the toner supply device, and the connection portion opens. When the toner supply device is separated from the developing device, the developer restricted by the permanent magnet 11 closes the opening.
Further, the developer flowing back to the toner supply device is attracted to the permanent magnet 11 side and collected. Since the elastic body 10 which is a magnetic body is attracted by the permanent magnet 11 outside the opening 3b, the suppressing force of the backflow prevention valve 8 is improved.
A rib 3a of about 7 mm is provided at the edge of the opening 3b of the housing case 3, and a circular annular permanent magnet 11 having an inner diameter entering the rib 3a at the opening edge of the housing case 3 is prepared, and this is fitted to the outer periphery of the opening. Then fix with adhesive. When the opening 3b is about φ15 mm, a magnet of about 800 gauss was used.
In this case, when the tip 5 of the toner supply device is separated from the developing device, the opening 3 b of the housing case 3 is closed by the developer regulated by the permanent magnet 11.

FIG. 5 is a schematic cross-sectional view showing a third embodiment of an A portion surrounded by a schematic square in FIG. An air inlet 16 is disposed on the upper surface of the stirring chamber of the housing case 3, an air outlet 15 is disposed between the backflow prevention valve 8 and the tip 5 of the toner supply device, and a blower mechanism 17 is disposed between the air inlet 16 and the air outlet 15. Is arranged.
The air blowing mechanism 17 performs an operation of blowing the air on the stirring chamber side to the vicinity of the backflow prevention valve 8. Since the toner is blown off by the air, the blown-off toner can be supplied to the stirring chamber.
Since the toner is blown off by the air, it can be supplied to the stirring chamber. Since the toner to be collected around the opening is blown off and diffused, it is possible to prevent unstirred toner from being supplied to the developing unit, thereby preventing image abnormality due to toner scattering.
A φ10 mm air inlet 16 is provided on the upper surface of the stirring chamber of the housing case 3, and a φ3 mm air outlet 15 is disposed between the backflow prevention valve 8 and the toner supply device tip 5. A tube body 20 is provided between the air inlet 16 and the air outlet 15, and a blade-type fan air blowing mechanism 17 is installed between the air inlet 16 and the air outlet 15 inside the tube, and the air blowing mechanism 17 is rotated. The toner in the vicinity of the backflow prevention valve 8 is moved by the air sent by the fan.
By preventing unstirred toner from being supplied to the developing unit, image abnormality due to toner scattering and toner contamination of the image forming apparatus can be prevented.

1 is a schematic cross-sectional view illustrating a configuration of an embodiment of a developing device according to the present invention. It is a schematic sectional drawing which shows 1st Embodiment of the A section of FIG. It is a schematic sectional drawing which shows the modification of 1st Embodiment of FIG. It is a schematic sectional drawing which shows 2nd Embodiment of the A section of FIG. It is a schematic sectional drawing which shows 3rd Embodiment of the A section of FIG.

Explanation of symbols

1 Developer 2 Stirring Member 3 Housing Case (Housing)
3b Opening 5a Toner supply device tip (toner supply device)
6 Toner supply mechanism 8 Backflow prevention valve 10 Elastic body 11 Permanent magnet 12 Developer carrier (developing roller)
13 Latent image carrier (photosensitive drum)
14 Developer restricting member 15 Air outlet 16 Air inlet 17 Air blowing mechanism

Claims (10)

  In a developing device comprising a housing case that contains a developer and a stirring member that is rotatably supported in the housing case and stirs and conveys the developer, an opening connecting the tip of the toner supply device is provided in the housing case. A developing device, wherein the developing device is provided below the rotational center height of the stirring member on the outer wall.   The developing device according to claim 1, further comprising a backflow prevention valve that opens and closes the opening.   The developing device according to claim 2, wherein an elastic body that urges the backflow prevention valve in a closing direction is disposed between the backflow prevention valve and a part of the housing case.   The developing device according to claim 2, wherein a permanent magnet is disposed in the vicinity of the opening.   The developing device according to claim 4, wherein the backflow prevention valve is a magnetic material.   The developing device according to claim 3, wherein the elastic body is a magnetic body.   The air outlet is provided between the tip of the toner supply device and the backflow prevention valve, the air inlet is provided on the upper surface of the stirring chamber, and the air blowing mechanism is provided between the air outlet and the air inlet. The developing device according to claim 6.   An image forming unit comprising the developing device according to claim 1.   An image forming apparatus comprising the developing device according to claim 1.   An image forming apparatus comprising the image forming unit according to claim 8.

Images