JPH07333988A - Developing device of electrophotographic device - Google Patents

Abstract

PURPOSE:To surely prevent the developer leakage from the both end of developing roller without increasing a rotational load of the developing roller in a developing device of electrophotographic device performing the developing while preventing the developer leakage outside in the roller shaft direction with a sealing member by holding the sealing member in press-contact with the periphery of the both end of the developing roller. CONSTITUTION:The both end part 23b of a developing case 23 is respectively formed into a recessed hemi-cylidrical shape corresponding to the both end periphery of a developing roller 30, a sealing members 40 are stuck on the recessed part 23c, and the sealing members 40 are respectively brought into press-contact with the both end peripheries of the developing roller 30. The sealing member 40 is provided with the slot 41 extended in the rotary direction A of the developing roller 30 on the center part nearer the upstream side in the rotary direction A, and composed that the contact area with respect to the developing roller 30 is made larger on the downstream side than the upstream. Moreover, the sealing member 40 is composed so that the sealing property is made larger on the downstream side than the upstream side.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention can be applied to an electrophotographic apparatus that records on paper by an electrophotographic method, such as a printer, a copying machine, and a facsimile, using a laser. Specifically, in the electrophotographic apparatus, the developer replenishing member replenishes the developer to the developing roller, and the developing roller is rotated to attach the developer to the photoconductor, thereby forming a latent image on the photoconductor. The present invention relates to a developing device for visualizing an image.

[0002]

2. Description of the Related Art Conventionally, in a developing device of this type, as shown in an exploded view in FIG. 9, for example, both side portions 1a of a developing case 1 correspond to the shape of both end peripheral surfaces 2a of a developing roller 2. To form a concave shape, and the sealing members 3 are attached to the concave portions 1b, respectively, and the sealing members 3 are pressed against the peripheral surfaces 2a of both ends of the developing roller 2 to the outside in the roller axial direction indicated by the arrow C in the figure. There is a structure that prevents developer leakage.

During development, the developing roller 2 is rotated while the seal member 3 prevents the developer from leaking to the outside C in the roller axial direction. Then, the developing roller 2 is replenished with the developer from the inside of the developing case 1, the adhered developer is thinned by the thinning blade 4, and the thinned developer is exposed by the developing roller 2. It adhered to the body (not shown) and made the latent image on the photoreceptor visible.

[0004]

By the way, in such a conventional developing device, in order to enhance the sealing property of the seal member 3, the seal member 3 shown by reference numeral a in FIG. 10 is used.
It is better to increase the width in the roller axis direction and the length b indicated by the symbol b. However, if the sealing property is increased, the rotational load of the developing roller 2 increases correspondingly, which requires a large driving force, and there is a problem that the driving motor becomes large and the cost increases.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to improve the sealing property without increasing the rotational load of the developing roller, and reliably prevent the developer from leaking from both ends of the developing roller.

[0006]

Therefore, the present invention provides
For example, as shown in the illustrated embodiment below, the developing roller 3
While the seal member 40 is pressed against the peripheral surfaces of both ends of 0 to prevent the developer from leaking to the outer side C in the roller axial direction by the seal member 40, the developing roller 30 is rotated to attach the developer t to the photoconductor 13. In the developing device 16 of the electrophotographic apparatus that visualizes the latent image on the photoconductor 13, the sealing property of the seal member 40 is improved on the downstream side of the upstream side in the rotation direction A of the developing roller 30. It is characterized by

According to a second aspect of the present invention, for example, as shown in the following illustrated embodiment, the developing device 1 according to the first aspect.
6, the contact area of the seal member 40 with respect to the developing roller 30 is increased on the downstream side from the upstream side, and the sealing performance of the seal member 40 is improved.

According to a third aspect of the present invention, for example, as shown in the following embodiment shown in the drawings, the developing device 1 according to the first aspect.
6, the seal member 40 and a member at the upstream position thereof, for example, the mylar attachment convex portion 23a of the developing case 23.
It is characterized in that a viscous member such as grease is applied to a gap d between the and.

According to a fourth aspect of the present invention, for example, as shown in the following embodiment shown in the drawings, the developing device 1 according to the first aspect.
6, a developer replenishing member 31 that replenishes the developer t toward the developing roller 30, a thinning member 32 that thins the developer t adhering to the developing roller 30, and a thinning member thereof. At the upstream position of 32, the front end 45a is connected to the developing roller 3
And a seal blade 45 for preventing the developer t, which has been pressed against 0 and removed by the thinning member 32, from entering the seal member 40.

According to a fifth aspect of the present invention, for example, as shown in the following illustrated embodiment, the developing device 1 according to the fourth aspect.
6, the viscous member such as grease is applied to the tip 45a of the seal blade 45.

[0011]

In the present invention, the developing roller 3 is driven during driving.
Even if the developer t may enter between the developing roller 30 and the seal member 40 at the upstream position in the rotation direction A of 0, the developer t moves to the downstream position as the developing roller 30 rotates. And leaks the developer to the outer side C in the roller axial direction at the downstream position where the sealing property is improved.

According to the third aspect, the seal member 4
The viscous member prevents the developer t from leaking to the outer side C in the roller axial direction through the gap d between 0 and the member at the upstream position.

According to the fourth aspect, the thinning member 3
The seal blade 45 prevents the developer t removed in 2 from entering the seal member 40.

According to the fifth aspect of the invention, the developer t is supplied from around the tip end 45a of the seal blade 45 to the developing roller 3.
The viscous member prevents entry between 0 and the seal member 40.

[0015]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 3 is a schematic configuration diagram of a laser printer including a developing device according to an embodiment of the present invention.

In the figure, reference numeral 10 is a printer main body, and reference numeral 11
Is a paper feed cassette included in the printer body 10. Then, the paper P sent out from the paper feed cassette 11 in the arrow A direction is conveyed to the drum-shaped photoconductor 13 by the registration roller pair 12 at a timing. The photoconductor 13 is rotationally driven in the clockwise direction indicated by the arrow, at which time the surface is uniformly charged by the charging device 14, and the optical writing device 15
To form an electrostatic latent image on the photoconductor 13. This latent image is visualized by the developer when passing through the position of the developing device 16 according to the present invention, and this visible image is
The transfer device 17 transfers the transferred image to the paper P conveyed to the photoconductor 13, and the fixing device 18 fixes the transferred visible image on the paper P. Then, the paper P that has left the fixing device 18 is discharged onto the paper discharge unit 19 in the arrow B direction, for example. On the other hand, the residual developer is removed from the photoreceptor 13 after the transfer of the visible image by the cleaning device 20.

By the way, the above-mentioned developing device 16 is constructed as shown in FIG. 4, for example. Reference numeral 23 in the figure denotes a developing case. The developing case 23 includes a developing chamber 24 on the left side and a developer storage chamber 25 on the right side in the drawing.

The developing chamber 24 is provided with a developing window 26 on the side of the photoconductor 13, and a developing agent replenishing port 27 communicating with the developing agent storage chamber 25 is provided on the side opposite to the developing window 26. Then, in the developing chamber 24, the photoconductor 1 is inserted through the developing window 26.
3, a developing roller 30 is provided so as to face the developing roller 30, and a roller-shaped developer replenishing member 31 that comes into contact with the developing roller 30 is provided on the right side of the drawing.

As shown in FIG. 5, the developing roller 30 has a pitch of 0.3 mm and a depth of 0.
An iris knurling process is performed at 1 mm, a groove width of 0.2 mm, and an angle of 45 degrees to form a mesh-shaped dielectric layer 30a as shown in an enlarged view in FIG. On the other hand, the developer supply member 31
As shown in FIG. 4, a carbon kneaded foamed polyurethane sponge 31b is provided around a central axis 31a.

Further, in the developing chamber 24, as shown in FIG. 4, a blade-shaped thinning member 32 which is long in the roller axis direction of the developing roller 30 is provided on the upper side thereof. The base end side of the thinning member 32 is supported by the developing case 23, and the front end side is in contact with the peripheral surface of the developing roller 30.

Further, in the developing chamber 24, the developing roller 3
A long seal mylar 33 along the roller axis below 0
Equipped with. Then, the base end side of the seal mylar 33 is attached to the mylar attachment convex portion 23a of the developing case 23, and the tip end side is brought into contact with the peripheral surface of the developing roller 30.

On the other hand, in the developer storage chamber 25, the developer t
, And two agitators 35 that convey the developer t to the developing chamber 24 while stirring the developer t are rotatably provided.

During development, the driving force of a drive motor (not shown) is transmitted to rotationally drive these agitators 35, and the developing roller 30 and the developer replenishing member 31 are rotationally driven in the directions of arrows A and B in the figure. To do. Then,
The developer t in the developer storage chamber 25 is transferred to the two agitators 35.
It is conveyed to the developing chamber 24 through the developer replenishing port 27 while being stirred. Then, the developer replenishing member 31 triboelectrically charges the developer t and adheres it to the developing roller 30, and the adhered developer is thinned to a predetermined thickness by the thinning member 32. The converted developer is electrostatically attached to the photoconductor 13 by the developing roller 30, and the latent image on the photoconductor 13 is visualized.

By the way, the developing device 16 described above is shown in FIG.
As shown in FIG. 2, both sides of the developing case 23 (one side omitted) 2
3b is formed in a semi-cylindrical concave shape corresponding to the peripheral surfaces of both ends of the developing roller 30, and the sealing member 40 is attached on the concave portion 23c. Then, the seal members 40 are pressed against the peripheral surfaces of both ends of the developing roller 30 to prevent the developer from leaking to the outside in the axial direction of the roller indicated by the arrow C in the figure.

The sealing member 40 is formed, for example, by providing a bristle brush on a sponge and has a thickness of about 2 mm.
Further, the amount of the developing roller 30 biting into the seal member 40 is set to 0.5 mm. The seal member 40 has a long hole 41 that is long in the rotation direction A of the developing roller 30 and is formed in the central portion in the upstream of the rotation direction A, and has a larger contact area with the developing roller 30 on the downstream side than the upstream side. . As a result, the sealing performance of the seal member 40 is improved on the downstream side from the upstream side. Then, as shown in FIG. 4, the lower end is abutted against the Mylar attachment convex portion 23a of the developing case 23, and the upper end is arranged so as to extend right below the thinning member 32. Note that, for example, grease, which is a viscous member, is applied to a gap between the lower end portion of the seal member 40 and the Mylar attachment convex portion 23a, which is indicated by an arrow d in FIG.

Therefore, in the developing device 16 described above, when the developing device 16 is driven, the developer t is temporarily provided between the developing roller 30 and the seal member 40 at the upstream position in the rotation direction A of the developing roller 30.
Even if there is a problem, the developer t moves to the downstream position as the developing roller 30 rotates, and at the downstream position where the sealing property is improved, the developer leakage to the roller axial outside C is prevented. To do. Further, at that time, by leaking a part of the developer t that has entered into the elongated hole 41 and retaining it therein, leakage of the developer can be prevented more effectively. Furthermore, since the gap between the lower end of the seal member 40 and the Mylar mounting convex portion 23a is closed by the above-mentioned grease, the developer t is prevented from leaking to the outer side C in the roller axial direction through the gap.

By the way, in the present invention, as shown in FIG. 7, for example, the sealing blades 45 may be attached to the lower surfaces of both ends of the thinning member 32 in the length direction. The seal blade 45 is formed of a bristle brush having a thickness of 0.5 mm and a width of 9.5 mm, for example. The tip 45a of the seal blade 45
The lower surface side of the developing roller 30 is pressed against the upper end portion of the seal member 40, and the lower edge portion of the tip 45a is connected to the developing roller 30.
Be pressed against. Further, the tip 45a of the seal blade 45 is formed by applying, for example, grease, which is a viscous member, to the portion indicated by the chain line in FIG.

However, in the other illustrated embodiment, at the time of development, the developer removed by the thinning member 32 is stopped at the tip 45a of the seal blade 45, and the developer is transferred to the developing roller 3.
0 and the seal member 40 are prevented from entering. Further, since grease is applied to the tip 45a of the seal blade 45, the developer is not applied to the tip 45a.
It is more reliably prevented from entering between the developing roller 30 and the seal member 40 through the gap between the developing roller 30 and the developing roller 30.

By the way, in the illustrated embodiment described above,
By increasing the contact area of the sealing member 40 with the developing roller 30 on the downstream side of the upstream of the developing roller 30 in the rotation direction A, the sealing property of the sealing member 40 is improved on the downstream side of the upstream. However, according to the present invention, for example, by increasing the pressing force of the seal member against the developing roller on the downstream side from the upstream side, the sealing performance can be similarly improved on the downstream side from the upstream side. In that case, in order to increase the pushing force on the downstream side from the upstream side,
For example, it is possible to change the material of the seal member to increase the elastic force on the downstream side from the upstream side.

[0030]

Therefore, according to the present invention, the contact area of the seal member with respect to, for example, the developing roller is increased on the downstream side from the upstream side in the rotation direction of the developing roller, and the sealing performance of the seal member is improved on the downstream side from the upstream side. However, since the sealing property is only partially increased, it is possible to reliably prevent the developer from leaking from both ends of the developing roller without significantly increasing the rotational load of the developing roller.

According to the third aspect of the invention, the viscous member is applied to the gap between the seal member and the member at the upstream position, and the developer leaks through the gap to the outside in the roller axial direction. To prevent the development roll
It is possible to more reliably prevent the developer from leaking from both ends of the roller.

According to the fourth aspect of the present invention, the seal blade prevents the developer removed by the thinning member during development from entering the seal member.
It is possible to more reliably prevent the developer from leaking from both ends of the developing roller.

According to the fifth aspect of the present invention, a viscous member is applied to the tip of the seal blade to prevent the developer from entering the seal member from around the tip of the seal blade. It is possible to more reliably prevent the developer from leaking from both ends of the roller.

[Brief description of drawings]

FIG. 1 is a partial perspective view showing one side portion provided with a seal member of a developing device according to an embodiment of the present invention.

FIG. 2 is a partial perspective view showing a grease application position of the seal member.

FIG. 3 is an overall schematic configuration diagram of a laser printer including the developing device.

FIG. 4 is a schematic sectional view of the developing device.

FIG. 5 is a schematic perspective view of a developing roller included in the developing device.

FIG. 6 is a partially enlarged view of the peripheral surface of the developing roller.

FIG. 7 is a schematic sectional view showing a developing chamber side of a developing device according to another embodiment of the present invention.

FIG. 8 is an enlarged cross-sectional view showing a grease application position of a seal blade provided in the developing device.

FIG. 9 is a schematic exploded perspective view of a conventional developing device.

FIG. 10 is a perspective view of a seal member included in the developing device.

[Explanation of symbols]

 13 Photoreceptor 16 Developing Device 23a Mylar Mounting Convex Part (Member at Upstream Position) 30 Developing Roller 31 Developer Replenishing Member 32 Thinning Member 40 Sealing Member 45 Seal Blade 45a Tip of Sealing Blade A Rolling Direction of Developing Roller C Roller Axial outside d Gap t Developer

Claims (5)

[Claims] 1. A developing roller is rotated to attach a developing agent to a photosensitive member while pressing a sealing member against the peripheral surfaces of both ends of the developing roller to prevent the developing agent from leaking outward in the axial direction of the roller. In the developing device of the electrophotographic apparatus that visualizes the latent image on the photoconductor, the electrophotographic apparatus is improved in sealing performance by the sealing member on the downstream side from the upstream side in the rotation direction of the developing roller. Developing device. 2. The developing device for an electrophotographic apparatus according to claim 1, wherein a contact area of the seal member with respect to the developing roller is increased on a downstream side from an upstream side to enhance sealing performance by the seal member. 3. A viscous member is applied to a gap between the seal member and a member located upstream thereof.
The developing device of the electrophotographic apparatus according to 1. 4. A developer replenishing member for replenishing the developer to the developing roller, a thinning member for thinning the developer adhering to the developing roller, and an upstream position of the thinning member. The developing device for an electrophotographic apparatus according to claim 1, further comprising: a seal blade that presses a front end of the developing roller against the developing roller to prevent the developer removed by the thinning member from entering the sealing member. 5. The developing device for an electrophotographic apparatus according to claim 4, wherein a viscous member is applied to the tip of the seal blade.