JP2000242078A - Developing device for image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a developing device making a leak of the developer as a result of a fitting error of a controlling member of the developing device preventable, with a simplified structure without requiring excellent assembling accuracy. SOLUTION: When a developing sleeve 14 is rotated in the direction of the arrow (a), a pad 20 is scraped by rubbing thereof, and fine particles M peeled off are transported up to the controlling member 15 being stuck onto the developing sleeve 14 leaving as it stands. Since the controlling member 15 is held in contact with a periphery on the developing sleeve 14 with a specific pressure, fine particles M being scraped off are not permitted to pass through the beneath of the controlling member, and heaped in the fine space formed on the both end part of the developing sleeve 14 both end part, heaped in a fine space formed by the controlling member 15, and the developing sleeve 14 and the sealing member 16, therefore the leak of the developer from the both end part of the developing sleeve can be prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a developing device for an image forming apparatus.

[0002]

2. Description of the Related Art In image forming apparatuses such as copying machines and printers, dry developing type developing apparatuses for developing an image latent image formed on a photoreceptor with a powder developer are widely used. In a developing device of the dry developing system, a regulating member for adjusting the layer thickness of the developer on the developing sleeve to an appropriate value is arranged.

FIG. 10 is a sectional view showing the structure of a conventional developing device, and FIG. 11 is an enlarged sectional view showing a main part thereof. 10 and 11, reference numeral 101 denotes a developing device main body, 102 denotes a photosensitive drum, 103 denotes a developing sleeve, and 1 denotes a developing sleeve.
04 is a magnet roller, 105 is a developer stirring drum,
Reference numeral 106 denotes a regulating member that adjusts the layer thickness of the developer on the developing sleeve to an appropriate value, and extends along the entire length of the developing sleeve along the axial direction of the developing sleeve 103. The magnet roller 104 is for forming a magnetic brush on the developing sleeve 103 in a developing device using a developer including a toner and a magnetic carrier.

[0004] As shown in FIG.
The developing sleeve 103 is arranged substantially perpendicularly with a slight interval t therebetween. The developer inside the developing device main body is stirred by the developer stirring drum 105 and adheres on the developing sleeve. The layer thickness of the developer adhered on the developing sleeve is regulated to a predetermined value by the regulating member 106, and the amount of the developer is kept at an appropriate amount.

In this configuration, since the excess developer that cannot pass under the regulating member 106 flows toward the lower side of the powder pressure, the developer flows along the regulating member 106 at both ends in the axial direction of the developing sleeve 103. The developer flows from both ends of the regulating member 106 into the apparatus.

FIG. 12 is a plan view showing the structure of the developing sleeve 103 and the end of the regulating member 106. In order to prevent the developer from leaking from both ends of the regulating member 106, both ends of the regulating member 106 are prevented. 2 shows a configuration in which the seal member 107 is disposed, and the seal member 107 is disposed so as to abut on both ends of the regulating member 106.

FIG. 13 is a cross-sectional view showing another example of the structure of the conventional developing device. The developing device is formed on the outside of the drive roller 121 with a conductive flexible material having an outer diameter larger than that of the drive roller. A cylindrical developing sleeve 122 is fitted, and the developing sleeve 122 can be rotated by a frictional force between the outer surface of the drive roller 121 and the inner surface of the developing sleeve 122. In this developing device, a one-component developer containing no magnetic carrier is used.

In this configuration, since the outer diameter of the developing sleeve 122 is larger than the outer diameter of the driving roller, the regulating member 126
"Slack" occurs in a direction substantially opposite to the position where the contact is made, and the "slack" portion contacts the photoreceptor 128 arranged at this position and forms an electrostatic latent image formed on the photoreceptor. Is developed.

In FIG. 13, reference numeral 126 denotes a regulating member. At a position R on the opposite side of the developing region D by approximately 180 °, the free end of the regulating member 126 is in contact with the outer surface of the developing sleeve 122. Free end of the developing sleeve 1
22 are arranged in a direction facing the rotation direction.

The developer adhering to the surface of the developing sleeve 122 moves in the direction of the arrow b due to the movement of the developing sleeve. At a position R, the thickness of the developer is regulated by the regulating member 126, and at the same time, the developer is regulated. A thin layer is formed on the developing sleeve 122 by being charged to a predetermined polarity by friction with the member 126.

Development sleeve 122 and drive roller 121
From the developing bias power supply 130 to the developing bias voltage Vb.
Is applied, when the developer in the "slack" portion comes into contact with the photoconductor 128, the developer is transferred to the photoconductor, and the electrostatic latent image formed on the photoconductor is developed.

[0012] Also in this configuration, since the developer that cannot pass through the tip of the regulating member 126 flows toward the lower powder pressure,
The developer easily leaks from both ends of the regulating member 126.

FIG. 14 is a drawing showing the configuration of the end portions of the developing sleeve 122 and the regulating member 126. FIG. 14 is a plan view of the vicinity of the position R in FIG. As a countermeasure for preventing the developer from leaking from both ends of the regulating member 126, a state is shown in which a seal member 129 is arranged from the back side (the side opposite to the developing sleeve) of the regulating member 126. .

[0014]

SUMMARY OF THE INVENTION FIG. 10 and FIG.
In the conventional developing device described with reference to FIGS. 1 and 12, if there is an error in the mounting position between the regulating member 105 and the sealing member 106, a gap d is formed between the regulating member and the sealing member as shown in FIG. In some cases, there is a disadvantage that the developer leaks from the gap in the direction of the arrow.

Further, in the conventional developing device described with reference to FIGS. 13 and 14, there is a gap corresponding to the thickness of the regulating member between both ends of the regulating member 126 and the sealing member 129. There is a disadvantage that the developer leaks in the direction of the arrow.

The present invention solves the above-mentioned inconvenience of the regulating member in the developing device, and provides a developing device which does not require a high degree of assembly precision and can prevent leakage of the developer with a simple structure. It is intended for.

[0017]

SUMMARY OF THE INVENTION The present invention solves the above-mentioned problems, and the invention according to claim 1 is an image forming apparatus which supplies a developer to an image forming member to form an image. A developer supply member for supplying the developer to the forming member, a regulating member for adjusting the layer thickness of the developer on the developer supply member to a predetermined value, and a surface facing the regulating member and the developer supply member. A seal member disposed at both ends adjacent to each other, and a pad that rubs against both ends adjacent to the developer supply surface of the developer supply member, wherein the pad rubs against the developer supply member Fine particles are deposited in the gap between the regulating member and the seal member to close the gap to prevent leakage of the developer.

According to a second aspect of the present invention, in a developing device of an image forming apparatus for supplying a developer to an image forming member to form an image, a developer supply member for supplying a developer to the image forming member; A regulating member that adjusts the layer thickness of the developer on the supply member to a predetermined value; and a sealing member disposed at both ends adjacent to a facing surface of the regulating member and the developer supply member.
A pad that rubs against both ends adjacent to the image forming surface of the image forming member, wherein the pad rubs against the image forming member to become fine particles, and the fine particles form a gap between the regulating member and the seal member. And the gap is closed to prevent leakage of the developer.

The regulating member may further include a scraping member for scraping the fine particles on the developer supply member.

The pad is selected from a material having a lower hardness than the developer supply member and a brittle material. For example, the pad can be formed of a material mainly composed of a fluororesin or a material mainly composed of wax.

[0021]

Embodiments of the present invention will be described below.

[First Embodiment] FIG. 1 is a sectional view showing the structure of a developing device according to a first embodiment of the present invention, and corresponds to an improvement of the conventional developing device described above with reference to FIG. I do.

In FIG. 1, reference numeral 11 denotes a developing device main body;
Denotes a photosensitive drum as an image forming member, 13 denotes a driving roller, 14 denotes a developing sleeve as a developer supply member, and 15 denotes a regulating member. The developing sleeve 14 includes the driving roller 13
It is a cylindrical body made of a conductive flexible material having a larger outer diameter than that of the conductive roller, and is fitted outside the drive roller 13. The developing sleeve 14 is rotated by a frictional force between the outer surface of the driving roller 13 and the inner surface of the developing sleeve 14. As the developer, a non-magnetic one-component developer is used.

In this embodiment, the developing sleeve is made of a flexible material having conductivity, for example, a conductive synthetic resin film, but is not limited to this.
Other materials, such as conductive rubber, can also be used.

The regulating member 15 is substantially 180 degrees from the developing area D.
At a position R on the opposite side, the free end of the regulating member 15 is in contact with the outer surface of the developing sleeve 14 with a predetermined pressure, and the free end of the regulating member 15 is disposed in a direction facing the rotating direction of the developing sleeve 14. Have been.

Both ends of the regulating member 15 are sealed by a sealing member 16 disposed on the back side (the side opposite to the drive roller 13) so that the developer does not leak. The seal structure by the seal member is the same as the conventional structure shown in FIG.

The developer on the developing sleeve 14 moves as the developing sleeve 14 rotates in the direction of the arrow a, and the layer thickness is regulated by the regulating member 15 at the position R. An agent layer is formed.

On the downstream side in the rotation direction of the developing sleeve 14, there are arranged pads 20 that come into contact with the outer surface of the developing sleeve 14 near both ends thereof. The mounting structure, material, function, and the like of the pad 20 will be described later in detail.

A developing bias voltage Vb is applied to the developing sleeve 14 and the driving roller 13 from a developing bias power supply 17. On the other hand, since the outer diameter of the developing sleeve 14 is larger than the outer diameter of the driving roller 13, a regulating member is provided. A “slack” occurs in a direction substantially opposite to the position where 15 is in contact, and the “slack” portion becomes the development region D. When the developer in the “slack” portion comes into contact with the photoconductor 12, the developer on the developing sleeve 14 is transferred to the photoconductor by the developing bias applied to the developing sleeve 14 and the driving roller 13.
The electrostatic latent image formed on the photoconductor is developed.

FIGS. 2 and 3 are views showing the details of the configuration near the mounting portions of the developing sleeve 14, the regulating member 15, and the pad 20, FIG. 2 is a sectional view thereof, and FIG. 3 is a front view thereof. .

As is apparent from FIG. 2, the pad 20 is fixed to a supporting member 18 provided on the developing device 11 via a leaf spring 19, and the pad 20 is
4 is pressed against the plate 4 at an appropriate pressure by the urging force of the leaf spring 19. As shown in FIG. 3, the position where the pad 20 is pressed against the developing sleeve 14 is near both ends of the developing sleeve 14, and the position in the axial direction (the axial direction of the developing sleeve) is the same as the position of both ends of the regulating member 15. Seal member 16 for sealing
It is in the position which overlaps.

The material of the pad 20 is a fluorine-based synthetic resin,
For example, a material mainly composed of Teflon (trade name), wax (W
AX) as a main component, or other material, which is cut off by sliding when pressed against the rotating developing sleeve 14 and is separated into fine particles. Form.

Next, the operation will be described with reference to FIG. 2 showing a contact portion between the developing sleeve and the regulating member and FIG. 4 which is an enlarged sectional view thereof. When the developing sleeve 14 rotates in the direction of the arrow a, the pad 20 is scraped off by the rubbing, and the fine particles M that have fallen off are conveyed to the regulating member 15 while adhering to the developing sleeve 14.

Since the regulating member 15 is in contact with the outer surface of the developing sleeve 14 at a predetermined pressure, the particles M peeled off from the pad 20 and the particles M transported by the developing sleeve 14 pass below the regulating member 15. The regulating member 15 and the developing sleeve 14 are provided at both ends of the developing sleeve 14.
It accumulates in a minute space SP formed by the seal member 16 and the seal member 16. Space SP by repeating the image forming operation
When the space SP becomes full, the developer does not leak from both ends of the developing sleeve 14, and the leak of the developer can be surely suppressed.

Hereinafter, an experimental example will be described.

Pressing force for pressing the regulating member against the developing sleeve: 5 g / mm Pad size: 8 mm × 4 mm × 3 mm (axial length × circumferential length × thickness) Pressing force for pressing the pad against the developing sleeve : 50 g Pad material: (1) Material containing Teflon (trade name) as a main component (2) Material containing wax (WAX) as a main component As a result of an experiment conducted under the above conditions, (1) Teflon ( (Trade name) as main component, (2)
In any case of the wax (WAX) -based material, after about 100 image forming operations are performed, the leakage of the developer completely disappears, and the amount of the developer that has leaked so far also decreases. It was found that it was slight and had no practical problem.

[Second Embodiment] FIG. 5 is a cross-sectional view showing a structure around a photosensitive drum, a developing sleeve, and a regulating member of a developing device according to a second embodiment of the present invention. Second
Since this embodiment includes the same components as those of the first embodiment, the same reference numerals are given to the same components as those of the first embodiment, and the detailed description will be omitted.

That is, the developing device of the second embodiment includes a photosensitive drum 12 serving as an image forming member, a developing sleeve 14 serving as a developer supply member, a driving roller 13, and a regulating member 15, and The sealing member 1 in which both ends of the regulating member 15 are disposed on the back side (the side opposite to the drive roller 13)
The components sealed by 6 to prevent leakage of the developer are the same as those of the developing device of the first embodiment,
The second embodiment is different from the second embodiment in that the pad 20 is configured to be pressed against the photosensitive drum 12 as an image forming member.

The pad 20 is fixed to a support member provided in the developing device 11 (not shown) via a coil spring 25, and the pad 20 is pressed against the photosensitive drum 12 at an appropriate pressure by the urging force of the coil spring 25. ing. The position where the pad 20 is pressed against the photosensitive drum 12 is
Is located near both ends separated from the image forming surface, and its axial position is at a position overlapping with a sealing member 16 that seals both ends of the regulating member 15.

As with the first embodiment, the material of the pad 20 is a synthetic resin, for example, a material mainly composed of Teflon (trade name), a material mainly composed of wax (WAX),
A block of other material is used, which is made of a material that, when pressed against the rotating photoreceptor drum 12, is scraped off by the rubbing of the photoreceptor drum 12, breaks down into fine particles, and forms a block.

Next, the operation will be described. When the photosensitive drum 12 rotates in the direction of arrow a, the pad 20 is scraped by the rubbing, and the fine particles M that have fallen off are removed from the photosensitive drum 1.
At the contact position between the developing sleeve 14 and the developing sleeve 14.
And the sheet is transported to the regulating member 15.

Hereinafter, since the behavior of the particles M is the same as that of the first embodiment described with reference to FIG. 4, it will be described below with reference to FIG. Since the regulating member 15 is in contact with the outer surface of the developing sleeve 14 at a predetermined pressure, the particles M peeled off from the pad 20 cannot pass below the regulating member 15 and both ends of the developing sleeve 14 Is accumulated in the minute space SP formed by the regulating member 15, the developing sleeve 14, and the seal member 16. By repeating the image forming operation, the particles M accumulated in the space SP gradually increase, and when the space SP becomes full, the leakage of the developer from both ends of the developing sleeve 14 is prevented.

[Third Embodiment] FIG. 6 is a cross-sectional view showing a structure around a photosensitive drum, a developing sleeve, and a regulating member of a developing device according to a third embodiment of the present invention.
This corresponds to the improvement of the conventional developing device described with reference to FIGS.

In FIG. 6, reference numeral 32 denotes a photosensitive drum as an image forming member, 33 denotes a developing sleeve as a developer supply member, 34 denotes a magnet roller, and 36 denotes a regulating member.
The regulating member 36 is disposed substantially perpendicularly to the developing sleeve 33 with a small interval t, and regulates the layer thickness of the developer attached on the developing sleeve 33 so as to maintain the developer in an appropriate amount. It is configured. In this embodiment, a two-component developer composed of a magnetic carrier and a toner is used as the developer.

On the downstream side of the regulating member 36 of the developing sleeve 33, pads 40 abutting near both ends of the outer surface of the developing sleeve 14 are arranged so as to be pressed by a coil spring 41 with an appropriate pressing force. .

The positions where the pads 40 are pressed against the developing sleeve 33 are near both ends of the developing sleeve 33. The material of the pad 20 is the same as that described in the first and second embodiments, such as a synthetic resin, for example, a material mainly containing Teflon (trade name), a material mainly containing wax (WAX), and other materials. The material is formed into a block by using a material having such a property that when it is pressed against the rotating photosensitive drum 12, the material is scraped off by the rubbing and peels off as fine particles.

FIG. 7 shows the developing sleeve 33 and the regulating member 3.
6 is a plan view showing a configuration of an end portion, and FIG. 8 is a cross-sectional view showing an enlarged configuration of the end portion. As a measure for preventing the developer from leaking from both ends of the regulating member 36, seal members 37 are arranged at both ends of the regulating member 36, and the regulating member 36 and the seal member 37 are arranged so as to partially overlap. ing.

The sealing member 37 is provided with a scraping member 38 at a portion overlapping the regulating member 36, and the scraping member 38 is configured to be in pressure contact with the developing sleeve 33 at a predetermined pressure. Suitable materials for the scraping member include stainless steel and synthetic resin.

Next, the operation will be described. When the image forming operation is started and the developing sleeve 33 rotates in the direction of the arrow a, the pad 40 is scraped off by the rubbing, and the fine particles M that have fallen off are conveyed to the regulating member 36 while adhering to the developing sleeve 33.

The particles M on the developing sleeve 33 conveyed to the regulating member 36 are scraped off by the scraping member 38 provided on the regulating member 36, and the regulating member 36 and the developing sleeve 3 are removed.
3 and gradually increases as the image forming operation is repeated, thereby closing the gap between the regulating member 36 and the developing sleeve 33 and preventing leakage of the developer from the gap.

In the first to third embodiments described above, the regulating member is made of a synthetic resin material. However, the material of the regulating member is not limited to this, but may be a material such as elastic rubber. Can also be used.

Further, it goes without saying that this developing device can be applied not only to a developing device of an ordinary electrophotographic image forming apparatus but also to an imaging cartridge including the developing device.

In addition to the developing device of the electrophotographic image forming apparatus, the present invention can be applied to, for example, a developing device of a direct recording type image forming apparatus. An image forming apparatus of the direct recording type employs a developing sleeve 4 as shown in FIG.
3. An image forming method in which the developer on the substrate 3 is caused to fly on the transfer drum 45 or on a recording sheet held on the transfer drum 45 by an electric field generated between the electrodes 42 provided on the substrate 41 to form an image. Device.

Even in the direct recording type image forming apparatus, it is necessary to form a thin layer of the developing agent on the developing sleeve 43. Therefore, a regulating member 46 is provided to form a thin layer of developer on the developing sleeve 43.
In order to prevent the developer from leaking from both ends of the
Alternatively, by adopting a configuration in which the pad 47 that rubs against the developing sleeve 43 is employed in exactly the same manner as the configuration described in the third embodiment, leakage of the developer from both ends of the developing sleeve 43 can be prevented. Can be.

[0055]

As described above, the present invention is directed to developing from a gap between a developer supply member for supplying a developer to an image forming member and a regulating member for regulating a layer thickness of the developer on the developer supply member. The leakage of the developer is to prevent the leakage of the developer by depositing fine particles peeled off from the pad rubbing the developer supply member or the image forming member in the gap between the developer supply member and the regulating member. Does not require high assembly accuracy,
Leakage of the developer can be prevented with a simple configuration.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view illustrating a configuration of a developing device according to a first embodiment.

FIG. 2 is a cross-sectional view showing details of a configuration around a developing sleeve, a regulating member, and a pad of the developing device shown in FIG.

FIG. 3 is a front view showing details of a configuration around a developing sleeve, a regulating member, and a pad of the developing device shown in FIG. 1;

4 is an enlarged cross-sectional view showing a contact portion between a developing sleeve and a regulating member of the developing device shown in FIG.

FIG. 5 is a cross-sectional view illustrating a configuration around a photosensitive drum, a developing sleeve, and a regulating member of a developing device according to a second embodiment.

FIG. 6 is a cross-sectional view illustrating a configuration around a photosensitive drum, a developing sleeve, and a regulating member of a developing device according to a third embodiment.

FIG. 7 is a plan view showing a configuration of a developing sleeve and an end of a regulating member of the developing device shown in FIG. 6;

FIG. 8 is an enlarged cross-sectional view illustrating a configuration of an end portion of a developing sleeve and a regulating member of the developing device illustrated in FIG. 6;

FIG. 9 is a cross-sectional view illustrating a configuration near a developing device of an image forming apparatus of a direct recording type.

FIG. 10 is a cross-sectional view illustrating a configuration of a conventional developing device.

11 is a cross-sectional view showing a mounting structure of a regulating member of the conventional developing device shown in FIG.

FIG. 12 is a plan view showing a configuration of an end of a developing sleeve and a regulating member of the conventional developing device shown in FIG.

FIG. 13 is a sectional view showing another example of the configuration of the conventional developing device.

FIG. 14 is a plan view showing the configuration of a developing sleeve and an end of a regulating member of the conventional developing device shown in FIG. 11;

FIG. 15 is a plan view for explaining the inconvenience based on the error in the mounting position between the regulating member and the seal member of the conventional developing device described with reference to FIGS.

[Explanation of symbols]

 11 Developing device main body 12, 32, photoreceptor drum (image forming member) 45 transfer drum (image forming member) 13 drive roller 14, 33 developing sleeve (developer supply member) 34 magnet roller 15, 36, 46 regulating member 16, 37 sealing member 38 scraping member 19 leaf spring 20, 40, 47 pad 25, 41 coil spring

Claims (6)

[Claims] An image forming apparatus that supplies a developer to the image forming member to form an image by supplying the developer to the image forming member; A regulating member that adjusts the layer thickness of the developer to a predetermined value; sealing members disposed at both ends adjacent to the opposing surfaces of the regulating member and the developer supply member; and a developer supply surface of the developer supply member. A pad that rubs on both ends adjacent to each other, wherein the pad rubs against the developer supply member and becomes fine particles, and the fine particles accumulate in a gap between the regulating member and the seal member to close the gap; A developing device for the image forming apparatus, wherein leakage of the developer is prevented. 2. A developing device of an image forming apparatus for supplying a developer to an image forming member to form an image, wherein the developer supplying member supplies the developer to the image forming member; A regulating member that adjusts the layer thickness of the developer to a predetermined value; sealing members disposed at both ends adjacent to the opposing surfaces of the regulating member and the developer supply member; and an adjoining image forming surface of the image forming member. A pad that rubs on both ends of the image forming member, the pad rubs against the image forming member to become fine particles, and the fine particles accumulate in a gap between the regulating member and the seal member to close the gap. A developing device for an image forming apparatus, wherein leakage of a developer is prevented. 3. The developing device according to claim 1, wherein the regulating member further includes a scraping member that scrapes the fine particles on the developer supply member. 4. The developing device for an image forming apparatus according to claim 1, wherein said pad is made of a brittle material having a lower hardness than a developer supply member. 5. The developing device for an image forming apparatus according to claim 4, wherein said pad is made of a material containing fluorine resin as a main component. 6. The developing device according to claim 4, wherein said pad is made of a material containing wax as a main component.