JPH0954493A - Developing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a developing device capable of surely prevented the leakage and scattering of developer from the longitudinal end part of a developer carrier with an easy constitution and without increasing the load torque of a device. SOLUTION: At each extension part extending outside the developing area in the longitudinal direction of a developing roller 33 for carrying/transferring toner and a control blade 34 for controlling the toner carried by the developing roller 33 so as to obtain a fixed quantity is contact with the developing roller 3, a brush sealing member 37 is arranged so that it may be held between the abutting parts of the control blade 34 and the developing roller 33. Besides, it is preferable to install the brush sealing member 37 on the extension part abutting on the developing roller 33.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a developing device used in an image forming apparatus such as a copying machine, a facsimile machine, a printer, and the like, and more specifically, to a sealing property at both longitudinal ends of a developer carrier of the developing device. It is about improvement.

[0002]

2. Description of the Related Art Conventionally, as a developing device of this type, a developer regulating member is brought into contact with a developer carrying member to regulate the amount of the developer on the developer carrying member to a predetermined amount, and the developer carrying member on the developer carrying member is regulated. It is known that the developer of (1) is conveyed to a portion facing the image carrier to visualize the latent image formed on the image carrier. In such a developing device, since the developer regulating member is in contact with the entire width in the longitudinal direction of the developer carrying member, the developer regulated at the contact portion between the developer carrying member and the developer regulating member is However, it spreads toward both ends in the longitudinal direction of the developer carrying member. If the developer spreads in this way, the developer may leak or scatter from both ends. When the developer leaks or scatters from the end portion in the longitudinal direction of the developer carrier, the developer may contaminate the inside of the image forming apparatus or the image, or the developer may not rotate on the rotary shaft of the developer carrier. This may cause troubles such as entering the bearing and locking the developer carrier.

Therefore, in the conventional developing device, various methods and devices have been proposed in order to prevent the developer from leaking or scattering from both ends in the longitudinal direction of the developer carrier of the developing device. For example, it is known that the contact pressure of the developer regulating members at both ends in the longitudinal direction is increased. Further, the side seal member is formed in conformity with the wedge-shaped gap shape between the developer regulating member and the developer carrying member, and the side seal member having the gap shape is formed at the longitudinal end portion of the developer regulating member.
A developing device has been proposed in which the developer regulating member and the developer carrying member are arranged so as to be sandwiched therebetween (see, for example, JP-A-62-62).
-192770 gazette). Further, there has been proposed a developing device in which a brush material or a foam material is applied to end faces of the developer carrying member and the developer regulating member in the longitudinal direction to prevent the developer from leaking or scattering (for example, actual development 2-73655). (See the official gazette).

[0004]

However, when the developer regulating member is brought into contact with the developer carrying member at the longitudinal end portion with a high contact pressure, the load torque on the developing device becomes large. There was a problem. Also,
When a wedge-shaped side seal member is used as in the developing device of JP-A-62-192770, the side seal member is aligned with the wedge-shaped gap between the developer carrying member and the developer regulating member. Difficult to make with high precision,
For example, if the side seal member is smaller than the wedge-shaped gap, leakage of the developer occurs. Conversely, if the side seal member is larger than the wedge-shaped gap, the developer regulating member floats and the developer cannot be regulated. There are problems that the developer is blown out and that the density unevenness of the image occurs on the longitudinal end side of the developer carrier. Moreover, the above-mentioned actual Kaihei 2-7365
When a brush material that contacts the end surface of the developer carrying member or the like is used like the developing device of No. 5, the developer carrying member and the developer regulating member have the same length and longitudinal position. And the end surface of the developer regulating member must be aligned.
If the end faces of the two do not match, a step is formed, and even if the brush material or the like is brought into contact, the developer leaks from the gap in the step.

The present invention has been made in view of the above problems, and an object of the present invention is to increase the load torque of the apparatus from a longitudinal direction end portion of the developer carrying member with a simple structure. It is an object of the present invention to provide a developing device capable of reliably preventing the developer from leaking or scattering.

[0006]

In order to achieve the above-mentioned object, a developing device according to a first aspect of the present invention comprises a developer carrying member carrying and carrying a developer, and the developer carrying member contacting with the developer carrying member. A developer regulating member for regulating the amount of the developer carried on the developer carrying body to a constant amount, each of the developer carrying body and the developer regulating member being outside the developing region in the longitudinal direction of the developer carrying body. In a developing device having an extending portion extending to
Wedge-shaped formed by the surface portion of the developer carrying member that moves toward the contact portion between the developer carrying member and the developer regulating member, and the surface portion of the developer regulating member facing the portion. A brush-like seal member for sealing the developer that moves to the outside of the developing area in the longitudinal direction of the developer carrier through the gap, the brush of the brush-like seal member is provided with the developer regulating member and the developer regulating member in the extending portion. It is characterized in that it is arranged in the gap in the extending portion so as to be sandwiched between the contact surfaces of the developer carrying member.

In the developing device of the first aspect, the developer carried on the developer carrying member is regulated to a predetermined amount at the contact portion with the developer regulating member. Then, the developer on the developer carrying member is conveyed to a portion of the image forming apparatus facing the image carrying member to visualize the latent image formed on the image carrying member. Here, due to the regulation of the developer regulating member, the developer whose pressure is increased moves toward the contact portion between the developer bearing member and the developer regulating member, and the developer bearing surface portion, An attempt is made to spread outward from the developing area in the longitudinal direction of the developer carrier through a wedge-shaped gap formed by the surface of the developer regulating member facing the portion. The developer outflow path is sandwiched by the respective contact surfaces of the developer regulating member and the developer carrier at the extending portion extending outside the developing region in the longitudinal direction of the developer carrier. The brush of the disposed brush-like seal member closes.

Particularly, the developing device according to claim 2 is the developing device according to claim 1, wherein the brush-like seal member is separated from the edge of the developing region by a predetermined distance in the longitudinal direction. It is characterized in that it is arranged so as to be sandwiched between the contact surfaces.

In the developing device of the present invention, the brush is sandwiched between the abutting surfaces at a position where the brush-like seal member is separated from the edge of the developing area by a predetermined distance in the longitudinal direction. By arranging
Compared with the case where the brush is sandwiched at a position closer to the edge of the developing area, the thickness of the brush sandwiched between the contact surfaces of the developer regulating member and the developer carrier is within the developing area. The contact state of the developer regulating member with the developer carrying member is not affected.

Particularly, in the developing device of claim 3, in the developing device of claim 1, the brush-like sealing member is arranged such that the bristle tips are inclined toward the downstream side in the rotation direction of the developer carrying member. It is characterized by.

In the developing device of the third aspect, since the bristle tips of the brush-like seal member are inclined toward the downstream side in the rotational direction of the developer carrying member, the brush of the seal member is the developer. A force that hinders the rotation of the carrier is not exerted on the developer carrier.

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment in which the present invention is applied to a developing device adopted in an electrophotographic copying machine (hereinafter referred to as a copying machine) which is an image forming apparatus will be described below. FIG.
1 is a schematic configuration diagram of a copying machine according to the present embodiment. In this copying machine, the image of the original 11 placed on the original placing table 10 includes an irradiation lamp 12a, a mirror 12b, and a lens 12.
The data is read by the image reading device 13 via c and the data is sent to the image processing device 14. The surface of the photoconductor 1 as an image carrier, which is rotationally driven in the direction of arrow A in the figure, is uniformly charged by the charger 2. Then, based on the data from the image processing device 14, a latent image corresponding to the image of the original 11 is formed on the surface of the photoconductor 1 by the exposure device 15 including a semiconductor laser, a polygon mirror, a reflection mirror, and the like. The latent image on the photosensitive member 1 is a developing roller 33 as a developer bearing member of the developing device 3 at a portion facing the developing device 3.
Is developed with a non-magnetic toner (hereinafter referred to as toner) as a developer to form a toner image. The toner image is transferred by the transfer / conveyance device 5 onto, for example, a transfer paper (not shown) conveyed by the registration roller 4 at a timing. The transfer paper on which the toner image is transferred is conveyed by the transfer / conveyance device 5, and when passing through the fixing device 6, the toner image is fixed and discharged to the outside of the machine. Here, the untransferred toner remaining on the photoconductor 1 after the transfer of the toner image is scraped off from the photoconductor 1 by the cleaning brush roller 71 of the cleaning device 7 and collected by the cleaning device 7. Then, the surface of the photoconductor 1 after cleaning is destaticized by the destaticizing lamp 8.

Next, the developing device 3 according to this embodiment will be described. FIG. 2 is a schematic configuration diagram of the inside of the developing device 3. The toner container 3a of the developing device 3 has an arrow D in the drawing.
Agitating / conveying members 31a and 31b that are rotationally driven in the direction to agitate and convey the toner are provided. Further, an opening 3b is formed in the developing device 3 at a position facing the photoconductor 1, and the opening 3b is made of a conductive material to which a predetermined bias voltage is applied and has an arrow in the drawing. A developing roller 33 is provided as a developer carrier that is driven to rotate in the B direction (counterclockwise direction). The developing roller 33 is rotationally driven in the direction of arrow C (counterclockwise direction) in the drawing and is in pressure contact with a supply roller 32 as a developer supply member made of an elastic foam material. Further, in the rotation direction of the developing roller 33, an elastic material is formed on the surface of the developing roller 33 on the downstream side of the pressure contact portion 3c with the supply roller 32 and on the upstream side of the opening portion 3b, and one end portion is developed. A free end portion of a regulating blade 34 as a developer regulating member fixed to the apparatus casing is in contact with the casing.

In the developing device 3 having the above structure,
The toner in the toner container 3a is agitated and conveyed by the stirring and conveying members 31a, 31.
It is sent to the supply roller 32 by b and the supply roller 3
2 supported on the surface. The toner carried on the supply roller 32 is supplied onto the developing roller 33 by the electrostatic force due to frictional charging caused by the peripheral speed difference between the supplying roller 32 and the developing roller 33 at the contact portion 3c with the developing roller 33. The toner supplied onto the developing roller 33 is regulated by the contact portion 3d with the regulating blade 34 to control the surplus toner to form a uniform toner layer. The layered toner adheres to the surface of the photoconductor 1 due to the potential difference between the developing roller 33 and the latent image on the photoconductor 1 to form a toner image.

FIG. 3 is a top view showing a schematic structure of a rear end portion of the developing device 3 having the above-mentioned structure in the longitudinal direction of the developing roller 33. The photoreceptor 1 has an image forming area at the center in the longitudinal direction, and has non-image forming areas at both ends in the same direction. Then, as shown in FIG. 3, the length of the developing roller 33 in the longitudinal direction is set to be longer than the length of the image forming area of the photoconductor 1 in the same direction, and the developing area at the center is the image forming area of the photoconductor 1. Facing each other. Further, each of the developer roller 33 and the regulation blade 34 has an extending portion that extends outside the developing area in the developing roller longitudinal direction, and the extending portions at both ends of the developing roller 33 are the same as those of the photoconductor 1. It faces the non-image forming area. The length of the restriction blade 34 in the longitudinal direction is set to be slightly shorter than the length of the developing roller 33 in the same direction. Further, the length of the supply roller 32 in the longitudinal direction is set to be the same as the length of the image forming area of the photoconductor 1 in the same direction, and is arranged so as to be in pressure contact with the developing area of the developing roller 33. .

Further, in the present embodiment, FIG.
As shown in the cross-sectional view of FIG. 3 (a cross-sectional view of the XX plane of FIG. 3 viewed from the direction of the arrow), the edge of the developing area is formed on the surface facing the developing roller 33 in the extending portion of the regulating blade 34. A brush-like seal member 37 is attached so that the bristle tips are caught at a position separated by a predetermined distance from. In addition, within a predetermined distance from the edge of the developing area, as shown in FIG.
As shown in the cross-sectional view of FIG. 3B (the cross-sectional view of the Y-Y plane of FIG. 3 viewed from the direction of the arrow), the tips of the brushes of the brush-like seal member 37 come into contact with the developing roller 33. .
The brush-like seal member 37 is made of a material having a low friction coefficient, for example, a Teflon-based fabric. The length of the fluff in the developing area is preferably set so as to fill the wedge-shaped gap, for example, a length of about 2 to 4 mm.

A side seal member 36 is attached to the inner wall of the casing 35 below the extending portion of the regulating blade 34 so as to be in contact with the peripheral surface of the extending portion of the developing roller 33 to prevent toner leakage. are doing.

According to this embodiment, the toner regulated by the abutting portion 3d passes through the abutting portion 3d and the wedge-shaped gap formed by the developing roller 33 and the regulating blade 34, and the length of the developing roller 33 increases. Even if it tries to spread toward both ends in the direction, the brush of the brush-like seal member 37 blocks the outflow path of the toner to the both ends in the longitudinal direction, so that the toner leakage and the toner scattering from the both ends are prevented. You can

5 (a) and 5 (b) show a concrete shape of the brush-like seal member 37 attached to the regulation blade 34. As shown in FIG. In this example, the brush-shaped seal member 37 is formed on the downstream side of the brush-shaped seal member 37 in the rotation direction of the developing roller 33 so as to have a convex portion or a tapered portion. The convex portion or the tapered portion is designed so that the hair tips are caught at a position separated from the edge of the developing area by a predetermined distance. By doing so, the thickness of the brush sandwiched between the contact surfaces of the developing roller 33 and the regulating blade 34 is smaller than that when the brush is sandwiched at a position closer to the edge of the developing area. The condition can be prevented from being affected. The regulation blade 34 of the present embodiment
Has elasticity, the thickness of the brush is absorbed by the elasticity of the regulation blade 34, so that the contact state between the developing roller 33 and the regulation blade 34 is less likely to be affected in the developing area. ing.

Further, since the brush-like seal member 37 is arranged so that the bristle tips face the downstream side in the rotation direction of the developing roller 33, as shown in FIGS. When 33 rotates, no force is applied from the tip of the brush to the root side. Therefore, the brush-like seal member 37
It is possible to prevent the regulation blade 34 to which is adhered from floating due to the rotation of the developing roller 33 and the brush-like seal member 37 itself from being peeled off from the regulation blade 34. Therefore, with a simple configuration in which the brush-like seal member 37 is attached to the regulation blade 34, it is possible to reliably prevent the toner from leaking or scattering, which tends to spread toward both ends in the longitudinal direction of the developing roller 33.

Further, since the bristles of the brush-like seal member 37 are only sandwiched between the developing roller 33 and the regulating blade 34, the regulating blade 34 is applied with a high contact pressure at both longitudinal ends of the developing roller 33. The load torque of the developing device 3 can be reduced as compared with the case of abutting. In particular, if a brush-like seal member 37 having a low friction coefficient with respect to the surface of the developing roller 33 and made of a material such as Teflon is used, the effect of reducing the load torque can be increased.

In the above embodiment, the brush-like seal member 37 is attached to the surface of the extension of the regulating blade 34 facing the developing roller 33. However, instead of this, the brush-like seal member 37 is used. The side seal member 36 may be attached to the end of the developing roller 33 on the downstream side in the rotation direction.

[0023]

According to the developing device of the present invention, the brush sandwiched between the contact surfaces of the developer carrying member and the developer regulating member extending outside the developing region in the longitudinal direction of the developer carrying member. -Shaped seal member is formed by the surface portion of the developer carrying member that moves toward the contact portion between the developer carrier and the developer regulating member, and the surface portion of the developer regulating member that faces the portion. Since the outflow path of the developer that attempts to spread toward the longitudinal end portions of the developer carrier through the wedge-shaped gap is blocked, the developer leaks from the longitudinal end portion of the developer carrier. There is an effect that scattering can be surely prevented.

Furthermore, since the brush of the brush-like sealing member is only sandwiched between the contact surfaces of the developer carrying member and the developer regulating member, the developer regulating member is provided at both longitudinal ends of the developer carrying member. It is possible to reduce the load torque of the developing device, as compared with the case of contacting with a high contact pressure.

In particular, according to the developing device of the second aspect, since the contact state of the developer regulating member with the developer carrying member in the developing area is made uniform, the developer regulating member is the developing device. It is possible to prevent contact failure with the developer carrier and to reliably prevent the developer from leaking or scattering from the longitudinal end of the developer carrier.

In particular, according to the developing device of the third aspect, since the brush of the brush-like seal member does not exert a force on the developer carrying member which hinders the rotation of the developer carrying member,
Unlike the case where the wedge-shaped side seal member is used, it is possible to prevent the developer restraining member from floating due to the rotation of the developer bearing member so that the developer cannot be regulated. It is possible to reduce the rotational torque load of.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram of a copying machine that employs a developing device according to the present embodiment.

FIG. 2 is a schematic configuration diagram of a developing device according to the present embodiment.

FIG. 3 is a top view of an end portion of the developing device.

FIG. 4A is an XX cross-sectional view showing a schematic configuration of a regulation blade and a brush-like seal member at an end portion of a developing roller of the developing device. (B) is the YY sectional view.

5A and 5B are explanatory views showing a specific shape of the brush of the brush-like seal member according to the present embodiment.

[Explanation of symbols]

 3 Developing Device 32 Supply Roller 33 Developing Roller 34 Control Blade 35 Casing 36 Side Seal Member 37 Brush-Shaped Seal Member

Claims (3)

[Claims] 1. A developer carrying member carrying and carrying a developer, and a developer regulating member which comes into contact with the developer carrying member and regulates the developer carried on the developer carrying member to a constant amount. In the developing device, wherein each of the developer carrying member and the developer regulating member has an extending portion that extends outside a developing region in the developer carrying member longitudinal direction, The developer through a wedge-shaped gap formed by the surface portion of the developer carrying member that moves toward the contact portion with the developer regulating member and the surface portion of the developer regulating member that faces the portion. A brush-shaped seal member for sealing the developer that moves to the outside of the developing region in the longitudinal direction of the carrier is provided at each of the developer regulating member and the developer carrier at the extending portion where the brush of the brush-shaped seal member is provided. So that you can touch it The developing device is arranged in the gap in the extending portion. 2. The developing device according to claim 1, wherein the brush is sandwiched between the abutting surfaces of the brush-shaped seal member at a position separated from the edge of the developing area by a predetermined distance in the longitudinal direction. A developing device, characterized in that 3. The developing device according to claim 1, wherein the brush-like seal member is arranged so that the bristle tips are inclined toward the downstream side in the rotation direction of the developer carrying member.