JPH1083121A - Image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a developing device capable of preventing the plastic deformation of a developer carrier caused by the abutting of an abutting member because it is left for a long period. SOLUTION: This device has a pressing spring 33 movably supporting the abutting member of a thin film regulating roller 6 or the like in a direction where it is brought into contact with or is separated from a developing roller 4 and also urging it on the side of the developing roller 4, and a stopper member 35 capable of displacing the thin film regulating roller 6 from a position where the movement of the roller 6 is stopped at the position where the stop of the movement of the roller 6 is released in a state where it is separated from the developing roller 4 by resisting the urging force of the pressing spring 33 is provided. Also, a tapered member 40 displacing the stopper member 35 from a stop position to a stop release position by the attaching operation of a developing device to an image forming device main body is provided at the image forming device main body.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an electrophotographic copying machine,
The present invention relates to a developing device in 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, as described above, since the abutting member is made of a material harder than the developing roller, such as metal or silicon, a recess may be formed on the surface of the developing roller. Was. The dent is formed by plastically deforming the developing roller, and often occurs particularly when the developing roller is in contact with the image forming apparatus for a long period of time from being manufactured to being mounted on the image forming apparatus main body. Then, when a dent is formed on the developing roller, there is a problem that the portion becomes a black streak and appears in an image. The present invention solves the conventional problem described above, It is an object of the present invention to provide a developing device that can prevent plastic deformation of a developer carrier caused by contact of members.

[0004]

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. A developing device in an image forming apparatus having an abutting member made of a material harder than the developer carrying member and abutting on the developer carrying member, wherein the abutting member is moved toward and away from the developer carrying member. A state in which there is provided an urging means for movably supporting the urging member toward the developer carrying member, and the contact member is separated from the developer carrying member against the urging force of the urging means. And a displacing member for displacing the contact member from the position where the movement is prevented to the position where the movement of the contact member is released. The blocking member is moved from the blocking position to the main body of the image forming apparatus by an operation of mounting the developing device to the main body. Displacement member that displaces to the blocking release position It is characterized by providing.

[0005]

According to the above construction, the developing device before being mounted on the image forming apparatus main body is held in a state where the contact member that comes into contact with the developer carrier is released by the holding means so that the contact pressure is released. The formation of a depression in the carrier can be reliably prevented. The holding operation can be eliminated by attaching the developing device main body to the image forming apparatus main body.

[0006]

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 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 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 are metal rollers 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 if 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 are formed. Is described earlier.

The present invention takes the following measures to solve such a problem. In FIG. 2, the developing device 2
On both sides, holding means constituted as a coil spring 11 for urging a pressing force in a direction to separate the toner collecting roller 7 from the developing roller 4 is provided so as to be able to contact the shaft 7a of the toner collecting roller 7. . In this case, one end of the coil spring 11 is locked by the locking portion 12 and the other end is
The shaft 7a extends to a position where it can be pressed.

Below the coil spring 11, there is provided an operating pin 14 fitted to the guide cylinder 13 so as to be vertically movable. A cam plate 15 that can swing between a position where the operation pin is lowered as shown in FIG. 2 and a position where the operation pin 14 is pushed up as shown in FIG. 3 is provided below the operation pin.
This cam plate 15 is provided on the copying machine main body side, and a shaft 16 to which the cam plate 15 is fixed is swung by a motor (not shown). The operating pin 14 and the cam plate 15 constitute a unit for canceling the pressing action by the coil spring 11 of this embodiment from the toner collecting roller 7.

In the developing device 2 thus configured, the cam plate 15 is provided on the copying machine main body side before being mounted on the copying machine main body. Therefore, the operating pin 14 may be pushed up as shown in FIG. Instead, it is lowered by its own weight of the operating pin 14 and is held at the position shown in FIG. 2 by a stopper (not shown). Accordingly, the coil spring 11 presses the toner collecting roller 7 in a direction away from the developing roller 4 via the shaft 7a, and is held in a state where the contact pressure of the toner collecting roller 7 is released (hereinafter, referred to as a released state). .
In this case, the mounting position of the developing roller 4 and the toner collecting roller 7 is fixed, but if the toner collecting roller 7 is pressed by the coil spring 11, the toner collecting roller 7 tends to separate from the developing roller 4 by a minute gap. The contact pressure is released.

Thus, before the developing device 2 is mounted on the copying machine main body, the contact pressure of the toner collecting roller 7 with the developing roller 4 is maintained in the released state, and the toner collecting roller 7 is separated on the developing roller 4. Is prevented from being formed.

Next, a description will be given of holding release means for returning the developing device 2 from the released state to the normal contact state after the developing device 2 is mounted on the copying machine main body. The cam plate 15 is connected to the control unit 2 shown in FIG.
Controlled by 0. The control unit 20 includes a power supply 2 of the copying machine.
1 and a signal of a sensor 22 for detecting whether or not the developing device 2 is mounted on the main body of the copying machine.
As a result, a drive signal is output to the motor 23 that operates the shaft 16.

The cam plate 15 is normally held at a position where the operating pin 14 is lowered as shown in FIG. 2. When the developing device 2 is mounted on the copying machine main body and the power supply 21 is turned on, the cam plate 15 is turned on. As shown in the flow of FIG. 5, when the sensor 22 is turned on and the power supply 21 is turned on, the operation from the release state to the contact state is performed. That is, as shown in FIG. 6, the shaft 16 rotates and the cam plate 15 raises the coil spring 11 via the operating pin 14.

As a result, the coil spring 11 separates from the shaft 7a of the toner collecting roller 7 and comes into contact with the developing roller 4 with pressure, so that a copying operation is performed. Also,
The developing device 2 is pulled out of the copying machine main body and the sensor 22
When the power supply is turned off or the power supply 21 is turned off, the operation of the release state is performed. That is, as shown in FIG.
6 rotates counterclockwise, the cam plate 15 moves down the operating pin 14 and separates from the coil spring 11, and the coil spring 11 presses against the shaft 7 a of the toner collecting roller 7. The cam plate 1
The swing of 5 is not limited to the motor, and a solenoid or the like may be used as a drive source.

According to the above configuration, the toner collecting roller 7 is of course used before the developing device 2 is mounted on the copying machine main body.
Since the release state is maintained even when the power is turned off, the plastic deformation of the developing roller 4 due to the pressure contact for a long time can be reliably prevented.

FIG. 8 is an explanatory view showing another embodiment of the present invention. Reference numeral 31 denotes a shaft of the thinning regulating roller 6, and the shaft 31 is formed by a pressing spring 33 through a bearing member 32. The pressure regulating roller 6 is pressed in the direction in which it contacts the developing roller 4. 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 projection 32a,
The developing device 2 before being mounted on the copying machine main body has its projection 3
2a is in contact with a stopper member 35 as a blocking member, and is held in a state where the contact pressure of the thinning regulating roller 6 with the developing roller 4 is released.

The stopper member 35 is movably fitted to a guide cylinder 37 fixed to the casing side plate 3, and is integrally provided with a pin 36 projecting outward from the stopper member 35. 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. 8 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. 9, and the developing device 2 is mounted on the copying machine main body in the direction of arrow A as a displacement member. When it is done, it is attached to the position where the pin 36 hits.

Before the developing device 2 thus constructed is mounted on a copying machine main body, as shown in FIG.
The second protrusion 32a is in pressure contact with the stopper member 35, so that the thinning regulating roller 6 is held in the 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. When the stopper member 35 separates from the protrusion 32a, 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 developing device 2 having the above-described structure, the thinning regulating roller 6 does not come into contact with 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. 11 shows still another embodiment of the present invention. In this embodiment, the stopper member 3 is configured similarly to FIG.
5, a concave member 41 is formed, while a side plate 39 of the copying machine main body is provided with a convex member 42 that can be fitted into the concave portion 41.
Although the moving force in the direction of arrow B is urged by the spring 43 on the convex member 42, the developing device 2 is normally held in the copying machine main body by a stopper (not shown).

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. 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-described embodiment, the developing device 2 before being attached to the copying machine main body holds the thinning regulating roller 6 in the released state, so that the plastic deformation of the developing roller 4 can be prevented. In this embodiment, the contact member is the toner collecting roller 7.
Although the thinning regulating roller 6 has been described, the present invention can also be applied to a thinning regulating blade or the like in which the contact member contacts the developing roller 4.

[0027]

According to the above construction, the present invention can hold 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 copying machine main body, and can prevent the contact of the contact member. The plastic deformation of the developer carrier caused by the contact can be reliably prevented.

[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 view showing a release state in a position embodiment of the present invention.

FIG. 3 is an explanatory diagram showing the contact state.

FIG. 4 is a block diagram of the control unit.

FIG. 5 is a control flow thereof.

FIG. 6 is another operation flow of each of them.

FIG. 7 is another operation flow of each of them.

FIG. 8 is an explanatory side view showing another embodiment of the present invention.

FIG. 9 is an explanatory plan view thereof.

FIG. 10 is an explanatory side view of the contact state.

FIG. 11 is an explanatory side view showing still another embodiment of the present invention.

FIG. 12 is an explanatory plan view thereof.

FIG. 13 is an explanatory side view of the contact state.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 photoreceptor drum 2 developing device 4 developing roller 6 thinning regulating roller 7 toner collecting roller 11 coil spring 14 operating pin 15 cam plate 35 stopper member 40 taper member 42 convex member

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[Procedure amendment]

[Submission date] July 4, 1997

[Procedure amendment 1]

[Document name to be amended] Statement

[Correction target item name] Full text

[Correction method] Change

[Correction contents]

[Document Name] Statement

[Title of the Invention] Image forming apparatus

[Claims]

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. An image forming apparatus including a developing device having a contact member made of a material harder than the developer carrying member and abutting on the developer carrying member, wherein the contact member is brought into contact with and separated from the developer carrying member. While supporting so that it can move in the direction,
An elastic urging means for urging an elastic force in a direction in which the contact member comes into contact with the developer carrying member; and at least a contact pressure from the developer carrying member against the urging force of the elastic urging means. And a blocking member that is locked with a part of the contact member at a position where the contact member is released, and that prevents movement of the contact member in a direction of contacting the developer carrier. It is characterized by being mounted so as to be displaceable between a locking position for locking the part and a locking release position for releasing the locking.

The present invention is effective when a displacing member for displacing the blocking member from the locked position to the unlocked position when the developing device main body is set in the image forming device main body is effective.

[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 projection 32a. Before the developing device 2 is mounted on the copying machine main body, the projection 32a 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.

The stopper member 35 is movably fitted to a guide cylinder 37 fixed to the casing side plate 3, and is integrally provided with a pin 36 projecting outward from the stopper member 35. 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.

Before the developing device 2 thus constructed is mounted on the copying machine main body, as shown in FIG.
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. Although the moving force in the direction of arrow B is urged by the spring 43 on the convex member 42, the developing device 2 is normally held in the copying machine main body by a stopper (not shown).

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-described embodiment, the developing device 2 before being mounted on the copying machine main body holds the thinning regulating roller 6 in the released state, so that the plastic deformation of the developing roller 4 can be prevented. In the above-described embodiment, the contact member is the toner collecting roller 7.
Although the thinning regulating roller 6 has been described, the present invention can also 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 hold the contact member pressure 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 copying machine main body. The plastic deformation of the developer carrier caused by the contact can be reliably prevented.

[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.

[Description of Signs] 1 Photoconductor drum 2 Developing device 4 Developing roller 6 Thinning regulating roller 7 Toner collecting roller 32a Projection 35 Stopper member 40 Taper member 42 Convex member

[Procedure amendment 2]

[Document name to be amended] Drawing

[Correction target item name] All figures

[Correction method] Change

[Correction contents]

FIG.

FIG. 2

FIG. 3

FIG. 4

FIG. 5

FIG. 6

FIG. 7

Claims (1)

[Claims] A developer supply member configured to supply a developer to the latent image carrier, at least a surface of which is constituted by a flexible elastic roller member; A developing device having an abutting member made of a harder material, wherein the abutting member is movably supported in a direction of coming into contact with or separating from the developer carrier, and is attached to the developer carrier side. A biasing means for urging the contact member against the urging force of the urging means to prevent movement of the contact member from a position where the contact member is prevented from moving in a state where the contact member is separated from the developer carrier. A blocking member that can be displaced to a release position, and a displacement member that displaces the blocking member from the blocking position to the blocking release position by an operation of mounting the developing device to the main body of the image forming apparatus. Developing device.