JP2965528B2 - Image forming device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an electrophotographic copying machine,
The present invention relates to an image forming apparatus such as a laser printer and a laser fax.

[0002]

2. Description of the Related Art As a developing device of an image forming apparatus, at least a surface for supplying a developer to a latent image carrier is formed of an elastic roller member having flexibility, and a developer carrier is provided on the developer carrier. And a contact member made of a material harder than the developer carrying member is known. In this type of developing device, members that come into contact with the developing roller include a thinning regulating member, a toner collecting member, and the like, and these contact members always contact the developing roller with an appropriate contact pressure.

[0003]

However, since the abutting member is made of a material harder than the developing roller, such as metal or silicon, the contact may form a depression on the surface of the developing roller. Was. The dent is formed by plastically deforming the developing roller, and often occurs when the developing roller is brought into contact with the image forming apparatus for a long period of time from when the roller is manufactured to when it is mounted on the image forming apparatus main body. Then, when such a dent is formed on the developing roller, there is a problem that the portion appears as a black streak on the image and the image quality is remarkably deteriorated.

[0004] The present invention solves the above-mentioned conventional problems,
An object of the present invention is to provide an image forming apparatus capable of preventing a plastic deformation of a developer carrying member caused by contact of a contact member after being left for a long period of time.

[0005]

In order to achieve the above object, the present invention relates to a developer carrier for supplying a developer to a latent image carrier, at least a surface of which is constituted by an elastic roller member having flexibility. abuts on the developer carrying member, have a abutment member material harder than the developer carrying member, before the abutment member
Supported so as to be movable toward and away from the developer carrier.
And an elastic urging means for urging the abutting member in a direction in which the abutting member comes into contact with the developer carrying member, and the urging force against the urging force of the elastic urging means. A blocking member that locks the contact member with a part of the contact member at a position where at least the contact pressure is released from the developer carrier, and prevents movement of the contact member in a direction of contacting the developer carrier; Locking the blocking member with a part of the contact member
Between the locked position and the unlocked position to release the lock.
An image of the developing device main body having a displacement member for displacing
Positioned at the locking position by the mounting operation to the forming apparatus body
The locking of the blocking member is released .

[0006]

[0007]

According to the above arrangement, the developing device before being mounted on the image forming apparatus main body is held in a state where the contact member abutting against the developer carrier is released from the contact pressure by the blocking member. The formation of a depression in the carrier can be reliably prevented. The state in which the contact pressure has been released can be resolved by mounting the developing device main body on the image forming apparatus main body.

[0008]

Embodiments of the present invention will be described below with reference to the accompanying drawings. FIG. 1 is a schematic diagram showing a developing device of a copying machine to which the present invention is applied.

In FIG. 1, reference numeral 1 denotes a photosensitive drum as a latent image carrier, and reference numeral 2 denotes a developing device. In the developing device 2, a developer carrier configured as a developing roller 4 is disposed at an opening of the casing 3, and the developing roller 4 is in contact with the photosensitive drum 1. Further, the developing device 2 includes a toner replenishing roller 5 for replenishing the developing roller 4 with toner, and a thinning regulating roller 6 for regulating the replenished toner to be thin.
And a developing roller 4 after development, a toner collecting roller 7 for collecting color toner, and an agitator 8 for stirring toner, and a blade for scraping toner on the peripheral surface of the thinning regulating roller 6 and the toner collecting roller 7 respectively. 9 and 10 are in contact.

The developing roller 4 is constituted by an elastic roller member having flexibility, that is, an elastic roller. On the other hand, the thinning regulating roller 6 and the toner collecting roller 7
Is a metal roller harder than the elastic body, and the thinning regulating roller 6 and the toner collecting roller 7 are in contact with the developing roller 4 with an appropriate contact pressure.

The developing device 2 has a problem that when the thinning regulating roller 6 and the toner collecting roller 7 are left in contact with the developing roller 4 for a long time, the developing roller 4 is plastically deformed and dents occur. Is described earlier.

The present invention takes the following measures to solve such a problem. In FIG. 2, reference numeral 31 denotes a shaft of the thinning regulating roller 6. The shaft 31 is moved in a direction in which the thinning regulating roller 6 comes into contact with the developing roller 4 by a pressing spring 33 as an elastic urging means via a bearing member 32. Pressed. The pressing spring 33 is provided in a spring guide 34 fixed to the casing side plate 3 of the developing device 2. The bearing member 32 is provided with a protrusion 32a. Before the developing device 2 is mounted on the copying machine main body, the protrusion 32a of the developing device 2 is attached to a stopper member 35 as a blocking member in a state where the pressing spring 33 is compressed. Locked. As a result, the thinning regulating roller 6 is held in a state where at least the contact pressure with the developing roller 4 is released, in the example shown in FIG.

[0013] The stopper member 35 is fitted movably in the guide cylinder 37 fixed to the casing side plates 3, further scan <br/> stopper member 35 is a pin 36 which projects outwardly is provided integrally I have. The pin 36 is fitted in a long hole 37a formed in the guide cylinder 37 and shown by a chain line in FIG. A spring 38 for pressing the stopper member 35 leftward in FIG. 2 is fitted in the guide cylinder 37.

On the other hand, a taper member 40 is fixed to the rear side plate 39 on the copying machine main body side as shown in FIG. 3, and the developing device 2 is mounted on the copying machine main body in the direction of arrow A as a displacement member. Is mounted at a position where the pin 36 hits when it is pressed.

The thus constructed developing unit 2, a copying machine pressing spring 33 as shown in FIG. 2 before mounting the body
The protrusion 32a of the bearing member 32 is formed against the stopper member 3 against the action of bringing the thinning regulating roller 6 into contact with the developing roller 4.
5, the thinning regulating roller 6 is held in a pressure released state.

Here, when the developing device 2 is mounted on the copying machine main body, the developing device 2 is slid in the direction of arrow A, and the pin 36 hits the tapered member 40 soon. When the developing device 2 reaches the final predetermined position, the pin 36 comes into contact with the tapered member 40, so that the stopper member 35 moves rightward in FIG. Then, the stopper member 35 is separated from the projection 32a, and the thinning regulating roller 6 is pressed against the developing roller 4 by the action of the pressing spring 33, as shown in FIG.

In the thus configured developing device 2, the thinning regulating roller 6 does not abut against the developing roller 4 before being mounted on the copying machine main body, so that the plastic deformation of the developing roller 4 can be prevented. If it is mounted on the copier body, it can be automatically brought into contact.

FIG. 5 shows another embodiment of the present invention. In this embodiment, a concave portion 4 is formed in a stopper member 35 constructed in the same manner as in FIG.
1 is formed, while a recess 41 is formed in the side plate 39 of the copying machine main body.
Is provided with a protruding member 42 that can be fitted to the. The moving force in the direction of arrow B is urged by a spring 43 in the convex member 42. However, when the developing device 2 is mounted on the copying machine main body by a stopper (not shown), the convex member 42 fits into the concave portion 41.
Is held in the position

Here, when the developing device 2 is mounted on the copying machine main body, the tip of the convex member 42 is fitted into the concave portion 41 as shown in FIG. At this time, the stopper is separated from the concave member 42 by a sensor that detects that the developing device 2 is mounted, and the convex member 42 moves in the direction of arrow B by the action of the spring 43. Then, when the stopper member 35 separates from the projection 32a of the bearing member 32, the thinning regulating roller 6 comes into contact with the developing roller 4 as shown in FIG.

Thus, similarly to the above embodiment, before the developing device 2 is mounted on the copying machine main body, the developing device 2 pushes the thinning regulating roller 6 into the pressure release state.
Held in state, preventing plastic deformation of the developing roller 4 Then DOO
When the pressure is released, the developing device 2 is attached to the copying machine.
This can be solved by the following operation. In the above embodiment, the contact members are the toner collecting roller 7 and the thinning regulating roller 6, but the present invention can be applied to a thinning regulating blade or the like in which the contact member contacts the developing roller 4.

[0021]

According to the above construction, the present invention can maintain the pressure of the contact member in a released state before mounting the developing device in which the plastic deformation of the developer carrier is most likely to occur to the image forming apparatus main body. contact with reliably prevent plastic deformation of the developer carrying member caused by this pressure releasing condition developing in
The device can be resolved by the mounting operation to the image forming device.
You.

[Brief description of the drawings]

FIG. 1 is a schematic diagram showing a developing device of a copying machine to which the present invention is applied.

FIG. 2 is an explanatory side view showing an embodiment of the present invention.

FIG. 3 is an explanatory plan view thereof.

FIG. 4 is an explanatory side view of the contact state.

FIG. 5 is an explanatory side view showing still another embodiment of the present invention.

FIG. 6 is an explanatory plan view thereof.

FIG. 7 is an explanatory side view of the contact state.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 photoconductor drum 2 developing device 4 developing roller 6 thinning regulating roller 7 toner collecting roller 32 a projection 35 stopper member 40 taper member 42 convex member

──────────────────────────────────────────────────続 き Continuation of front page (58) Field surveyed (Int.Cl. ⁶ , DB name) G03G 15/08-15/095

Claims (1)

(57) [Claims] 1. A developer carrying member which supplies a developer to a latent image carrying member, at least a surface of which is constituted by an elastic roller member having flexibility, and a developer carrying member which abuts on the developer carrying member and is in contact with the developer carrying member. It has a abutment member material harder than before the abutment member
Supported so as to be movable toward and away from the developer carrier.
In the image forming apparatus having a developing device are, the abutting member and an elastic biasing means for biasing the elastic force in a direction in contact with the developer carrying member, the person against the urging force of the elastic biasing means A blocking member that locks a part of the contact member at a position where the contact member releases at least the contact pressure from the developer carrier, and prevents movement of the contact member in a direction of contacting the developer carrier; The blocking member and a part of the contact member
A locking position for locking and a locking release position for releasing the locking
And a displacement member for displacing between the developing device main body and the developing device main body.
The locking position is determined by the mounting operation to the image forming apparatus main body.
Wherein the locking of the blocking member located in the image forming apparatus is released .