JPH0614220B2 - Image forming device - Google Patents

Description

The present invention relates to an image forming apparatus having two or more developing devices. In particular, the present invention relates to an image forming apparatus that performs development using different developers. The present invention can be applied to an electrophotographic image recording device, a copying machine, a printer, a printing machine, a facsimile and the like.

(Background Art) In recent years, recording devices have been downsized, and devices that achieve this have been provided.

However, due to the downsizing of the device, a small amount of developer can be accommodated in the device, and in the case where high-speed recording is required, the developer is used in a large amount, which is more likely to cause a problem.

On the other hand, when a large developer container (hereinafter, referred to as a hopper) is applied to a recording device, the volume space occupied by the container is extremely large, resulting in a large size of the device. On the other hand, a recent recording device has been proposed in which a plurality of developing devices are accommodated in different colors so that the recording device can be colorized, but the size of the device is only further increased.

(Object of the Invention) An object of the present invention is to provide an image forming apparatus capable of achieving contradictory downsizing, securing a developer storage amount, and housing the first and second developing devices.

Another object of the present invention is to make the use of the developing and forming device reliable and safe with respect to another developing device that uses a small amount of developer relative to a developing device that develops using a main developer. To do.

(Summary of the Invention) The present invention achieves the above object. A first invention is a first developing device and a second developing device that is detachable from an image forming apparatus provided above the first developing device. Control means for maintaining one of the first and second developing devices in a non-developing state when the other is in a developing action state, and a developer storage container of the first developing device provided on the side of the second developing device, A first position where the developer storage container is located in the attachment / detachment direction of the second developing device with respect to the image forming device to prevent attachment / detachment; and a second position which is separated from the attachment / detachment direction to permit attachment / detachment of the second developing device. The image forming apparatus is movable to two positions.

Further details of the invention will be understood by the following description.

(Examples) First, important items will be summarized in the following examples.

1. The downsizing of the apparatus can be achieved by the developer accommodating container of the first developing device provided on the side of the first developing device that is detachable from the development forming device provided above the first developing device.
Point 2. Further, the size can be further reduced by rotatably holding the developer container with respect to the image forming apparatus. The developer storage container moves to a first position where the second developing device is detachably attached to the image forming apparatus and prevents attachment and detachment, and a second position where the second developing device is separated from the attachment and detachment direction to permit attachment and detachment of the second developing device. Since the first developing device is movable and is used more frequently than the second developing device because the first developing device is close to the second developing device,
There are some points such as the stable and reliable use of the developing device, and the safe use of the image forming device.

The following description is for an electrophotographic copying machine, but the present invention is not limited to this. The present invention is characterized by what is described in the claims,
Other applications and configuration additions are included as preferred embodiments.

Next, the present invention will be described with reference to FIGS. 1 to 4 showing an embodiment thereof. In this embodiment, the image forming apparatus according to the present invention is embodied in an electrophotographic copying machine.

In FIG. 4, a latent image carrier, that is, the electrophotographic photosensitive drum 2 in this embodiment, is rotatably attached to the center of the image forming apparatus main body 1, and is rotated in the arrow X direction. A plurality of, in this embodiment, two developing devices 3 and 4 are arranged along the photosensitive drum 2. Each of the developing devices 3 and 4 has a developing operation position close to the photosensitive drum 2 and a photosensitive drum 2 in a known manner.
Is movable to and from a developing inoperative position separated from. The developing devices 3 and 4 may have various configurations, but a developer transport means for transporting the developer to the surface of the photosensitive drum 2, in this embodiment, a developing roll 3a having a magnet inside,
4a and is controlled so as to approach the photosensitive drum 2 only when the developing operation is required.

Further, according to the present embodiment, the hopper 5 for replenishing toner is provided in the vicinity of the developing device 3, the toner (black) mainly used is accommodated in the developing device 3, and the toner receiving port 3b for receiving the toner is received. The projection 3c for opening and closing the shutter 20 described later
And are respectively provided (see FIGS. 1 and 2).

On the other hand, the developing device 4 is a developing device that is rarely used,
Therefore, the toner itself stores a predetermined amount of toner, and the above-mentioned toner replenishing hopper is not provided in the vicinity thereof.

Here, the hopper 5 is located inside the apparatus main body 1 and in front of the developing device 4, and is provided close to the developing device 4 to the extent that it does not affect the moving operation of the developing device 4. Has been.

Further, the developing device 4 is detachably attached by pulling it out from the main assembly 1 of the apparatus when it is separated from the photosensitive drum 2.

Further, a charging device 6 is provided on the upper side of the photosensitive drum 2, and the charging surface of the photosensitive drum 2 is uniformly charged by the charging device 6. Photosensitive drum 2 charged in this way
Is a slit image exposure of the original image from the direction shown by the arrow 7 by an optical system or a laser scanner not shown,
An electrostatic image is formed.

This electrostatic image is visualized by the developing device 3 or 4 adjacent to the photosensitive drum 2. The visible image is transferred from the paper feed cassette 8 to the transfer paper P, which is supplied at the same timing as the developed image by the paper feed roller 9, the transfer paper double feed prevention roller pair 15, and the registration roller 10.
It is transcribed by the action of 1.

After that, the transfer paper P is separated from the photosensitive drum 2 by the separation charger 17, passes through the conveyance path 12 and the fixing device 13, and is discharged outside the device by the paper discharge roller 14.

On the other hand, the residual toner on the photosensitive drum 2 is removed by the cleaner 16, and the next image forming process is started.

Referring to FIG. 1 and FIG. 2, the hopper 5 for replenishing toner has a rectangular box shape as a whole, has a toner discharge port 5a on the lower surface thereof, and is planted on the upper surface and the lower surface. It is rotatably attached to the image forming apparatus main body 1 by the rotating shaft 5b. A transfer screw 18 is provided inside the hopper 5. The carrying screw 18 carries the toner driven by a motor 19 mounted outside the hopper 5 to the discharge port 5a.

Further, on the lower surface of the hopper 5, a plate-shaped shutter 20 which is located in a slight gap between the developing device 3 and the hopper 5 and has a substantially triangular shape is arranged, and is rotatable by the rotary shaft 21 to the hopper 5. Mounted on. A spring 22 is connected to a projection 20a formed at one end of the shutter, and the shutter 20 is biased in the direction of arrow A in FIG.

The shutter 20 includes the discharge port 5a of the hopper 5 and the developing device 3
To communicate with the receiving port 3b formed on the upper surface of the hopper 5
Although there is a hole 20b for allowing the toner to pass from the inside to the developing device 3, it is located at a position where the spring 22 always closes the discharge port 5a of the hopper 5 (the position shown by the dotted line in FIG. 4).

On the other hand, an operating member 3c for the shutter 20 is provided on the upper surface of the developing device 3, and the developing device 3 moves from the non-developing position to the developing operating position as shown in FIG. Sometimes engages with the side surface 20c of the shutter 20,
The shutter 20 is rotated counterclockwise in FIG. 3 against the force of the spring 22. By such rotation of the shutter 20, the discharge port 5a of the hopper 5, the receiving port 3b of the developing device 3, and the hole 20b of the shutter 20 are aligned and communicate with each other (state shown by a solid line in FIG. 3). In this state, when the amount of toner in the developing device 3 decreases, a known toner remaining amount detection sensor (not shown) operates to issue a toner replenishment signal and operate the motor 19 via the control circuit. Let The transport screw 18 is driven by the operation of the motor 19 so that the toner in the hopper 5 is discharged from the discharge port 5a to the hole 20b and the receiving port 3.
The developing device 3 is replenished with the toner of the same amount as the consumed amount by free fall after passing b.

Next, when the developing device 3 is moved to the developing inoperative position separated from the photosensitive drum 2, the engagement between the operating member 3c of the developing device 4 and the shutter 20 is released, and the shutter 20 is biased by the spring 22. 3 rotates in the direction of arrow A in FIG. 3, and the projection 20a of the shutter 20 engages with the stopper 20d to stop. This state is shown by the dotted line in FIG. 3, and the discharge port 5a of the hopper 5 is closed by the shutter 20. In this case, the discharge port 5 of the hopper 5
Although the positions of a and the receiving port 3b of the developing device 3 are displaced by the amount of movement of the developing device 3, since both the discharge port 5a and the receiving port 3b are shielded by the shutter 20, the leakage or the receiving port from the discharge port 5a. Mixing of scattered toner into 3b is prevented.

Further, when toner is supplied to the hopper 5 itself from the outside, the hopper 5 can be removed from the image forming apparatus main body, but the hopper 5 is rotated around the shaft 5b in the direction of arrow B in FIG. The toner may be replenished from above the hopper 5. In any case, the shutter 20 rotates in the direction of the arrow A by the urging force of the spring 22 and shields the discharge port 5a as described above, so that the toner does not leak from the hopper 5.

When removing the developing device 4 from the apparatus main body 1, the developing device 4 is rotated in the direction of arrow C with the hopper 5 being rotated in the same manner as when the hopper 5 is replenished with toner from the outside. Do it by pulling it toward you. On the contrary, when the developing device 4 is attached to the main assembly 1, the hopper 5 is also used.
When the apparatus main body 1 is subsequently operated, the developing device 4 is mounted at a predetermined position by returning the hopper 5 to the predetermined position. Here, the hopper 5 has a mechanism in which a not-shown apparatus main body front cover 50 returns to a predetermined position by a known method.

As described above, a hopper for replenishing toner to the first developing device, which is mainly used, is provided on the side of the second developing device that is less frequently used and is detachable, and the hopper is rotatably fixed. By doing so, it is possible to maximize the toner capacity in the hopper, and it is possible to reduce the size and cost of the image forming apparatus.

Further, when the second developing device is attached and detached, the hopper is positioned in the attaching and detaching direction, so that the hopper does not return to the predetermined position when the second developing device is not attached to the predetermined position. The mechanism is easy, and the second developing device can be reliably mounted by the operation of returning the hopper to a predetermined position.

Here, the operation of returning the hopper to a predetermined position can be performed by engaging with the opening / closing operation of the front cover or the like of the apparatus main body by a known method.

(Effects of the Invention) Since the present invention has the structure described in the claims, in the first invention, the attachment / detachment is controlled with respect to the detachable second developing device, and the miniaturization of the entire device can be achieved. An image forming apparatus capable of accommodating a large amount of the developer of the first developing device is provided, and in the second invention, the same effect as in the first invention can be more reliably obtained even if the developing device is a movable type.

[Brief description of drawings]

FIG. 1 is a top view of the essential parts of an embodiment of the present invention, FIG. 2 is a side view of FIG. 1, FIG. 3 is an explanatory view of the operation of a toner supply unit, and FIG. 4 is an implementation of FIGS. FIG. 5 is an overall view of an example, and FIG. 5 is an explanatory view of the action of the essential parts of the embodiment of the present invention. 1 is the image forming apparatus main body, 3 and 4 are developing devices, and 5 is a hopper.

Claims (1)

[Claims] 1. A first developing device, a second developing device provided above the first developing device and detachable from the image forming device, and one of the first and second developing devices is in a developing action state. At this time, it has a control means for maintaining the other non-developing state, and a developer accommodating container of the first developing device provided on the side of the second developing device, the developer accommodating container of the second developing device. Image formation characterized by being movable to a first position located in the attachment / detachment direction with respect to the image forming apparatus to prevent attachment / detachment and a second position spaced from the attachment / detachment direction to permit attachment / detachment of the second developing device apparatus.